FIELD OF THE INVENTION The present invention relates to systems and methods for separating quantities of product, and more specifically, to systems and methods for separating web product into clips having a desired count.

BACKGROUND OF THE INVENTION Numerous machines and processes exist for controlling the output of web product which is to be separated into bundles or"clips"of a desired product count. Although often used to refer to porous or semi-porous paper product in sheet form (e. g., napkin stock, paper toweling, tissue paper, toilet paper, and the like), the term"web"as used herein and in the appended claims is not limited to such product, and further encompasses any material that is found in sheet form and that can be folded. Examples of such alternative material include without limitation fabric, textiles, foils, synthetic sheeting, and the like. In certain industries such as the paper industry, the demand for a high volume of product has spurred the design and development of machinery which can produce stacks of web product at a much faster rate than was ever possible with earlier systems. Two examples of such systems are disclosed in United States Patent Number 4,770,402 issued to Couturier and United States Patent Number 5,730,695 issued to Hauschild et al., the teachings of which are incorporated herein by reference insofar as they relate to separation fingers and their associated mechanisms. Both patents address design difficulties regarding machines which stack product into clips having a desired number of folded items per clip. Many systems (including those of Couturier and Hauschild) employ a pair of folding rolls located above a stacking platform and a number of fingers which are manipulated to stack a stream of web product being folded upon the platform. After a number of web items (such as interfolded napkins or tissues) are stacked upon the platform, a set of fingers is inserted into the stream and is positioned above the stack upon the platform to define a clip having a known item quantity. A new clip is then formed above the fingers as the completed clip is lowered and moved to downstream operations.

In the prior art systems employing the above-described elements and system arrangement, a design problem arises in connection with the function and operation of the separation fingers which separate a completed clip from a clip being stacked.

With reference to FIG. 1 illustrating a prior art separator system, it can be seen that conventional separator finger mechanisms typically rotate the separation finger 50 about a single axis 51 through a range of positions into and out of a product stream 52 passing from between two folding rolls 6,7. It should be noted that only one separation finger 50 is shown in FIG. 1 for purposes of clarity. Most conventional systems employ a number of separation fingers 50 aligned side-by-side in a series which extends into the plane of the page of FIG. 1.

Also, although only one series of separation fingers 50 is shown on the left side of FIG. 1 (often, only one series is necessary to separate a completed clip from a new clip), an additional series of fingers can be located on the opposite side of FIG. 1 as a mirror image of the separation fingers 50. As disclosed in the Couturier patent mentioned above, multiple sets of separation fingers can be advantageously used for moving and parting the clips.

The path of motion taken by the separation fingers 50 is illustrated by the dotted line A shown on FIG. 1. Each separation finger 50 usually has a flat upper surface in order to permit a stack of product to be formed on top of the separation finger 50. The preferred flat upper surface and pivoting feature of the separation finger 50 results in the L shape found in many conventional separation fingers 50.

For proper control of the product stream leaving the folding rolls 6,7, it is necessary to have the separation finger surfaces (upon which the product is stacked) close to the nip 8 between the folding rolls 6,7. This orientation ensures proper folding and stacking of the product after it leaves the folding rolls 6,7. However, this design preference conflicts with the ability of the separation finger 1 to pivot about its axis 51. By placing the separation finger 50 close to the nip 8, the pivoting separation finger 50 interferes with the folding rolls 6. Prior art systems attempt to avoid this interference in various ways. For example, in the Couturier patent above, circumferential grooves are located in the folding rolls. The base of the circumferential grooves is indicated by way of example as dotted line B on FIG. 1. By locating each separation finger within a roll groove, the separation fingers have adequate clearance in their pivoting motion so that they do not interfere with the folding rolls (see the relationship between dotted lines A and B FIG. 1). A design drawback to this solution is that the grooves effectively weaken the folding rolls. Especially where long folding rolls are called for in a system and/or where the folding rolls need to be operated at relatively high speeds, numerous grooves in the folding rolls increase the chance for roll sagging, imbalance, and even failure. Another design solution to the separation finger and folding roll interference problem is disclosed in the Hauschild patent mentioned above. In the Hauschild patent, two sets of separating and carrying forks are used-one set on either side of the product stack being built. This design permits the forks to be made shorter and therefore less able to interfere with the folding rolls during fork movement. However, the Hauschild design requires two sets of separation fingers rather than one, and calls for a relatively complicated mechanism to properly position and insert the forks into the web stream (note how the forks must be positioned at a particular angle and position prior to being rotated into the web stream). Also, the short forks used in Hauschild are unable to fully support the stack being built thereon, as is evident from the gap between the forks when they are placed in their stack building position.

The design examples discussed above serve to illustrate the conflicting requirements of separation finger apparatuses. Long separation fingers provide adequate support for stacked product and can result in a simpler system design, but create problems with finger and roll interference and undesirable roll features such as weak rolls or rolls unable to operate safely at high speeds. Short separation fingers can help to avoid finger and roll interference, but typically require a more complicated and expensive design, can result in inferior stack support, and can create the need for more separation fingers.

Existing separation finger designs are also difficult to manufacture because they are relatively complex and require a large number of parts. Inevitably, because existing designs are difficult to manufacture, they are also difficult to repair and service. Simplicity in both design and construction is therefore desirable.

There are still further disadvantages of existing separation finger designs, all of which stem from the relative complexity of existing designs. Existing separation finger designs are limited in their effective operating speeds either by the capacity of their fingers to hold web product (stronger finger designs are often heavier with greater inertia) or by the necessity to put grooves in the rolls (which limits the maximum roll speed). Also, because existing designs require a relatively large number of parts, there is also significant energy loss due to friction, which results in a higher operating cost.

In light of the above design requirements and limitations, a need exists for a separator finger apparatus and method which provides adequate support for stacked product, utilizes a minimum number of separation fingers, has a simple design in which roll strength and speed capabilities are not compromised, locates separation fingers close to the folding rolls in their stack-building positions, ensures minimal interference between the separation fingers and the folding rolls during system operation, is easy to manufacture, repair, and service, requires minimal time to assemble and set up, is less expensive, operates with less friction, and requires less energy to operate than existing designs. Each preferred embodiment of the present invention achieves one or more of these results.

SUMMARY The present invention is a separation finger apparatus and method for inserting and removing a separation finger into a product stream or path in order to separate one group or "clip"of product from another. The present invention employs a number of features addressing the problems shared by conventional separation finger apparatuses.

The separation finger is coupled to elements which, when manipulated, pass the separation finger though an arcuately-shaped path. More preferably, the arcuately-shaped path is non-circular. Most preferably, the separation finger passes through the path by being simultaneously rotated and translated. While there exist a number of mechanisms and systems for accomplishing this task, the separation finger in a first preferred embodiment is coupled to a translation member, which itself is preferably mounted for rotation about an axis. The separation finger is also preferably rotatably mounted to a pivot arm which is itself mounted for rotation about an axis on one end of the pivot arm. By turning either the translation member about its axis or the pivot arm about its axis, the separation finger is caused to translate or slide along a length of the translation member, thereby causing the separation finger to translate as well as rotate about the translation member axis. The resulting motion of the separation finger is a rotation of the separation finger as it translates and orbits about the axis of the pivot arm.

By translating and rotating in the above-described manner, the separation finger can travel having less interference with adjacent folding rolls. This permits the separation fingers to be utilized without requiring deep grooves in the folding rolls (resulting in stronger rolls able to operate as faster speeds).

The translation member can take a number of different forms, and preferably is a pair of translation shafts upon which the separation finger translates or slides via a translation block attached to the separation finger. In a second preferred embodiment, the translation member is a finger guide having an elongated aperture in which the separation finger translates or slides. Preferably, the pivot arm and the translation member are both rotatably attached to respective pivot shafts which are preferably in fixed relationship to one another.

The unique motion of the separation finger provided by the present invention also results in the fact that longer separation fingers can be located more closely to the folding rolls. This permits the use of only one separation finger for bridging the stack-building surface upon which groups or clips of product are built. Such a design is simpler than the use in prior art systems of a pair of separation fingers (one on either side of the stack-building surface) to bridge the stack-building surface.

A third preferred embodiment of the present invention employs a separation finger directly or indirectly coupled to a cam follower. The cam follower is preferably coupled at one end to a cam member within, upon, or along which the cam follower rides or is otherwise guided. Preferably, movement of the cam follower is guided by the cam member having a surface along which the cam follower moves. More preferably, the cam member has a curved surface along which an extension from the cam follower rides. Most preferably, the curved surface in an interior surface of an aperture in the cam member. The cam follower and the separation finger are coupled to a first pivot member. In some embodiments, the first pivot member rotates about a first axis. In other embodiments, the cam follower is rotatable about the first axis while the first pivot member does not.

Preferably, the first pivot member of the third preferred embodiment can orbit about a second axis located a distance from the first axis and substantially parallel thereto. This relationship is preferably enabled by a pivot arm coupled to the first pivot member and to a second pivot member defining the second axis. The pivot arm is preferably rotatable about the first axis, and can be rotatable with respect to the first pivot member or coupled for rotation with the first pivot member. Similarly, the pivot arm is preferably rotatable about the second axis, and can be rotatable with respect to the second pivot member or coupled for rotation with the second pivot member. The first pivot member therefore allows the cam follower to rotate with respect to a second axis and to move (orbit) through an arc shaped path with respect to the second axis. The pivot member and pivot arm, acting together, enable the separation finger to move in a curved or bow-like path toward and away from web product passing through a passing stream of web product.

The separation finger preferably is longer than it is wide and has a relatively constant cross section. To reduce potential damage to the web product as it passes from the rolls, the separation finger can have a rounded, tapered, or blunted tip. The finger is preferably removably coupled to the cam follower to ease replacement of worn or damaged fingers.

With continued reference to the third preferred embodiment, the separation finger is preferably coupled to the cam follower at an end of the separation finger opposite the tip of the separation finger.

During operation the separation finger is extended toward the web material through an arc-shaped path. The finger will be positioned to receive and stack web product thereupon as the web product leaves the rolls. The separation finger apparatus of the present invention can then be moved to accommodate additional web product stacked upon the separation finger if desired. In any case, the separation finger preferably passes through an arc as the separation finger is retracted. Additionally, this motion allows the finger to retract from the stream of web material exiting the rolls without interfering with the motion of the roll. The extension and retraction motion of the separation finger can be repeated as often as desired for further clips of web product. In order to enable the separation finger to more closely approach the nip between the rolls, the separation finger can in some embodiments have a bend of any angle (e. g., preferably approximately ninety degrees).

With reference again to the third preferred embodiment, the cam follower can be a relatively long and narrow member cooperating with the cam member at one end and coupled to the first pivot member at another end. Of course, in different embodiments the relative locations of these connections can be substantially different. Notably, the connections between the cam follower and the first pivot member and the cam member need not necessarily be at opposite ends of the cam follower. However, the motion of the cam follower is constrained to some degree at least at two points: where it is coupled to the first pivot member and where it is guided by the cam member. The effect of constraining the cam follower in this manner is that the cam follower can direct the separation finger along the curved path as described above.

The cam member can have two parallel surfaces along which the cam follower or an extension of the cam follower travels. The surfaces can be straight to generate an arc-shaped motion of the separation finger, but more preferably are arc-shaped for the same purpose.

Preferably, the cam member is a piece of solid material with an aperture (most preferably arc- shaped) defined therein and defining the surfaces just mentioned. The cam follower or an extension of the cam follower travels along this aperture. The purpose of the cam member is to limit and direct the motion of the cam follower through a desired path.

While the cam member preferably guides the cam follower in a desired path, orientation of the cam follower is preferably controlled by the motion of the first pivot member. The first pivot member can be coupled to the cam follower at any point on the cam follower. The first pivot member is preferably a cylindrically shaped rod or shaft which allows the pivot arm and the cam follower to rotate with respect to one another. However, the first pivot member can have any other shape desired, preferably at least permitting rotation of the first pivot member relative to the cam follower or the first pivot member relative to the pivot arm. Specifically, in order to facilitate rotation of the cam follower and the pivot arm with respect to one another, the first pivot member is rotatably coupled to either the pivot arm or the cam follower and is preferably non-pivotably coupled to the remaining member. The first pivot member is therefore orbited in an arc about the second axis by movement of the pivot arm. This motion preferably causes the cam follower and the separation finger to move in an arc. By rotating while being moved in this arc, the separation finger moves through a complex motion of simultaneous rotation and translation.

The second pivot member, like the first, is preferably a cylindrical rod or shaft, but can be any other shape desired. The second pivot member is preferably rotatable about its own axis (also referred to as the second axis). Because the second pivot member is coupled by way of the pivot arm to the rest of the apparatus, rotation of the second pivot member preferably causes the entire assembly to move. In some preferred embodiments of the present invention, operation of the separation finger assembly is therefore accomplished by rotation of the second pivot member about its axis.

The present invention can be inexpensively manufactured because, as described above, there are relatively few components and the preferred embodiments employ relatively simple parts. This design further simplifies maintenance and repair of the apparatus. Also, minimal skill is required to repair and/or maintain the assembly, thereby reducing operating costs. Finally, set-up of the present invention can be significantly less complicated than set up of many contemporary separation finger assembly systems.

Because the present design allows the separation finger to more closely approach the nip of the folding rollers, numerous advantageous over contemporary separation finger designs are achieved. First, because longer fingers can be used at higher speeds, a minimum number of separation fingers are required (as compared to systems having separation fingers on both sides of the web product exiting the rolls). A reduction in the number of separation fingers results in a corresponding reduction in the cost of the entire assembly. Second, because the separation finger is moved toward and away from the stream of web material in a curved path via a combination of separation finger rotation and translation (rather than only pure rotation), interference between the separation finger and the rolls can be reduced. This can alleviate the need to cut grooves in the rolls or can allow the use of shallower grooves, thereby increasing the maximum operating speed of the rolls. Third, the web product is less likely to spool out of control or become entangled within the assembly because the separation finger is able to closely approach the nip between the rolls. This minimizes the time and distance that the web product is not in contact with either the rollers or the separation finger, providing for greater control of the product.

The present invention also addresses the problem of relative inefficiency, which is common in contemporary separation finger apparatuses. Because the present invention utilizes relatively few parts, there is minimal loss of energy due to friction between parts.

Further, many embodiments of the present invention utilize friction-reducing elements, thereby further reducing the friction and the resultant waist in energy. The aforementioned reduction in friction also reduces the wear experienced by the apparatus, resulting in an increased apparatus life, a reduction in repair and maintenance costs, and a reduction in down time caused by part failure.

Further objects and advantages of the present invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description of the, invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is further described with reference to the accompanying drawings, which show preferred embodiments of the present invention. However, it should be noted that the invention as disclosed in the accompanying drawings is illustrated by way of example only. The various elements and combinations of elements described below and illustrated in the drawings can be arranged and organized differently to result in embodiments which are still within the spirit and scope of the present invention. In the drawings, wherein like reference numerals indicate like parts: FIG. 1 is a cross-sectional view of a separator finger apparatus according to the prior art; FIG. 2 is a perspective view of the separator finger apparatus according to a first preferred embodiment of the present invention; FIG. 3 is a perspective view of the separator finger apparatus according to a second preferred embodiment of the present invention; FIG. 4 is a cross-sectional view of the separator finger apparatus according to the first preferred embodiment of the present invention, shown installed in a stacker of an interfolding machine; FIG. 5 is a perspective view of the separator finger apparatus according to the third preferred embodiment of the present invention; FIG. 6 is an exploded perspective view of the separator finger apparatus shown in FIG. 5; FIG. 7 is a cross-sectional view of the separator finger apparatus according to the third preferred embodiment of the present invention, shown in a retracted position; and FIG. 8 is a cross-sectional view of the separator finger apparatus according to the third preferred embodiment of the present invention, shown in an extended position.

DETAILED DESCRIPTION A first preferred embodiment of the present invention is illustrated in FIG. 2. The first preferred embodiment of the present invention has a separation finger apparatus (indicated generally at 10) capable of movement which is neither purely linear nor purely rotational. Specifically, the separation finger apparatus 10 preferably has a separation finger 12 translatably attached to a pair of translation shafts 14 which are themselves mounted for rotation about a first axis 16 preferably located at one end of the translation shafts 14. The separation finger 12 is also pivotably attached to a first end 18 of a pivot arm 20, which has a second end 22 mounted for rotation about a second or orbit axis 24. The pivot arm 20 and the separation finger 12 rotate about a third axis 25. The separation finger apparatus 10 can therefore rotate about two pivot points located at the first and second axes 16 and 24, thereby causing the separation finger 12 to simultaneously translate along the translation shafts 14 as it rotates about the third axis 25 at the first end 18 of the pivot arm 20. This relationship and movement of elements in the first preferred embodiment of the present invention permits the separation finger 12 to move in a non-circular and a nonlinear path. In particular, the separation finger 12 moves in an arcuate path as it travels toward and away from a stream of web product. The separation finger 12 rotates about the third axis 25 as it orbits about the second axis 24.

Looking now to the separation finger apparatus 10 in more detail, it should be noted that the separation finger 12 is preferably a thin elongated member which is of sufficient length to underlie substantially the entire width of a stack of product. This avoids the expense and complexity of two separation fingers 12 extending and meeting each other from opposite sides of the stack. The separation finger 12 is preferably attached in a conventional manner (such as by threaded fasteners, not shown) to a translation block 26. For ease of part replacement and maintenance, it is desirable to releasably attach the separation finger 12 to the translation block 26 with fasteners which themselves can be released and/or removed.

However, it is possible to make the separation finger 12 and the translation block 26 from one piece of material, or to permanently join the two elements together (such as by welding or gluing).

The translation block 26 preferably has a pair of holes 28 therethrough for receiving each of the translation shafts 14 with a clearance fit. This permits the translation block 26 to translate or slide up and down in translational engagement with the translation shafts 14 while maintaining and securing the separation finger 12 against rotation with respect to the translation block 26. The translation shafts 14 are preferably elongated rails or rods which can have virtually any cross-sectional shape.

It should be noted that the terms"translate"and"slide"and their various forms are used herein interchangeably. Both terms encompass any relationship between the translation block 26 and the translation shafts 14 (or other comparable elements as discussed herein) which permits one of the two elements to move in a manner which is not exclusively rotational or pivotal with respect to the other. Such movement includes without limitation movement of one of the elements through, along, beside, toward, or away from the other element. For example, in the first preferred embodiment of the present invention, the translation shafts 14 slide within and through the holes 28 in the translation block 26 when the separation finger 12 is extended or retracted. However, the terms"translate"and"slide" encompass alternative relationships such as where the translation shafts 14 are fitted with bearings of any type which themselves slide across the translation shafts 14, where the movement of the translation block 26 with respect to the translation shaft 14 is neither purely rotational nor purely non-rotational, where little to no physical contact occurs between the translation block 26 and the translation shafts 14 (such as in fluid bearings, with a magnetic or electromagnetic field causing the translation shafts 14 to"float"within the translation block 26), where one or more rollers or casters between the translation shafts 14 and the translation block 26 define rolling motion between the elements, and the like. All such manners of permitting relative and non-exclusively rotational movement between the translation shafts 14 and the translation block 26 fall within the spirit and scope of the present invention.

The translation block 26 and the separation finger 12 each preferably have pivot holes 30,32, respectively, which are aligned with one another. The pivot holes 30,32 are also preferably aligned with a pivot hole 34 in the first end 18 of the pivot arm 20. All three pivot holes 30,32,34 receive a pivot pin 36 which is retained therein in a conventional fashion (e. g., held by internally-threaded fasteners on each end of the pivot pin 36, secured via cotter pins on each end, etc.). The separation finger 12 and translation block 26 are therefore pivotably mounted via the pivot pin 36 to the pivot arm 20.

It will be appreciated by one having ordinary skill in the art that there exist a number of different ways in which the separation finger 12 and translation block 26 can be pivotably attached to the pivot arm 20. The particular arrangement disclosed herein is only one example of the many different elements and combinations of elements possible which achieve the same result of pivotably attaching the separation finger 12 and translation block 26 to the pivot arm 20. It is noted that the separation finger 12 can instead be sandwiched between the translation block 26 and the pivot arm 20, as opposed to the translation block 26 being sandwiched between the separation finger 12 and the pivot arm 20 illustrated in FIGS.

2 and 4. Also, the separation finger 12 (and translation block 26) need not necessarily be pivotably mounted to the pivot arm20 near or between the translation shafts 14 as shown in the figures. Instead, the pivot arm 20 can be pivotably mounted at another location along the separation finger, if desired. In short, the separation finger 12, pivot arm 20, and translation block 26, or equivalent elements can be coupled together (e. g., not necessarily physically touching each other), in a number of manners well-known to those skilled in the art to perform the functions described above. The same holds true for other preferred embodiments of the present invention, such as the second preferred embodiment described below.

The translation shafts 14 are preferably arranged in parallel relationship with one another and are attached in a conventional manner to a pivot head 38. Preferably, the pivot head 38 has a hole 40 therethrough sufficiently sized to receive a first pivot shaft 42. The translation shafts 14 can be attached to the pivot head 38 in any number of different ways well known to those skilled in the art. For example, the ends of the translation shafts 14 can be threaded and be received within threaded holes in the pivot head 38. The translation shafts 14 can instead be integral with the pivot head 38 (e. g., made from the same element), or can be permanently attached thereto via welding, gluing, etc. However, for service and maintenance purposes, it is preferable that the translation shafts 14 be releasably attached to the pivot head 38.

The pivot head 38 is preferably secured to the first pivot shaft 42 for rotation therewith. The pivot head 38 can be secured in a number of different conventional manners, such as via setscrews or bushings (not shown). However, the pivot head 38 is preferably a conventional clamp mount which is releasably tightened on the first pivot shaft 42. It will be appreciated by one having ordinary skill in the art that the pivot head 38 can take a number of shapes and forms, each capable of performing the function of securing the translation shafts 14 for rotation with the first pivot shaft 42. Such other arrangements fall within the spirit and scope of the present invention.

As mentioned above, the first end 18 of the pivot arm 20 is preferably pivotably attached to the separation finger 12 and the translation block 26. The second end 22 of the pivot arm 20 preferably has a hole therethrough of sufficient size and shape for receiving a second pivot shaft 44 (see FIG. 4). Preferably, the second end 22 of the pivot arm 20 is secured to the second pivot shaft 44 for rotation therewith. Like the pivot head 38, the pivot arm 20 can be secured to the second pivot shaft 44 in a number of different manners well-known to those skilled in the art (such as via setscrews, bushings, etc.). However, the second end 22 of the pivot arm 20 preferably is in the form of a conventional clamp mount releasably attached to the second pivot shaft 44. While the pivot arm 20 illustrated in the figures is preferably an elongated member, it will be appreciated by one having ordinary skill in the art that a number of different elements can be pivotably attached at both ends to achieve the same function as the pivot arm 20 disclosed herein.

The various elements of the separation finger apparatus 10 described above and illustrated in the drawings can be made from any number of materials, including metals (such as steel, aluminum, or iron), plastics, and composites, or combinations of the same. Other element materials include wood, fiberglass, glass, ceramics, and other refractory materials.

In the preferred embodiments of the present invention described herein, however, the separation finger 12, pivot arm 20, and pivot head 38 are all made of a relatively light-weight high-strength metal such as aluminum, while the translation block 26 is made from plastic (preferably, an engineered plastic such as ultra-high molecular weight plastic) for wear and translation or sliding purposes. To meet demanding strength requirements, the translation shafts 14 and the first and second pivot shafts 42,44 are preferably made from steel.

When installed within a system as shown in FIG. 4, the separation finger apparatus 10 is placed beneath the folding rolls 6,7 such that the separation finger 12 assumes a place beneath the nip 8 between the folding rolls 6,7 when the separation finger apparatus 10 is placed in its extended position shown in solid lines in FIG. 4. It should be noted that the separation finger apparatus 10 can be mounted in various operative locations within a system, dependent upon the desired function the separation finger apparatus 10 is to perform during system operation. For example, the separation finger apparatus 10 can be mounted for movement with the surface upon which stacked product is built, or can be mounted to a frame of the machine in which it is installed. Both examples are seen in the Couturier patent mentioned above (referring to the first and second count fingers 28 and 48 of Couturier, respectively). In the first example, the first and second pivot shafts 42,44 are preferably mounted for rotation in a conventional manner upon part of the mechanism or system which moves as product items are stacked upon the stack-building surface. Thus, the first and second pivot shafts 42,44 move with the surface upon which product is stacked. In the second example, the first and second pivot shafts 42,44 are preferably mounted for rotation in a conventional manner upon the frame of the machine in which the separation finger apparatus 10 is installed. In either case, the first and second pivot shafts 42,44 can be mounted via bearings (not shown) located on both ends of the pivot shafts 42,44, thereby keeping the pivot shafts 42,44 in fixed parallel relationship with one another. Other manners of rotatably securing the pivot shafts 42,44 are well-known to those skilled in the art, and are not therefore discussed further herein.

As can be seen from FIG. 4, with both pivot shafts 42,44 being secured in place with respect to one another (either on the machine frame, on a carriage, or on another element or assembly within the machine), rotation of one pivot shaft 42,44 causes the other pivot shaft to rotate and the separation finger 12 to move via the translation block 26 and translation shaft 14 connection. It should be noted that although not the preferred manner of operation, it is possible to mount the pivot shafts 42,44 for movement with respect to one another while still manipulating the elements of the separation finger apparatus 10 as described herein to achieve the same results. For example, movement of the lower pivot shaft 44 in an upward or downward motion toward or away from the upper pivot shaft 42 (respectively) will act to assist in the retraction and insertion (respectively) of the separation finger 12 by causing the translation block 26 to translate or slide along the translation shafts 14.

Although rotation of either pivot shaft 42,44 will cause the desired movement of the separation finger 12 through a continuous range of positions between its extended and retracted positions shown in FIG. 4, test results show that less torque is required to move the separation finger 12 by turning the second pivot shaft 44. As such, the second pivot shaft 44 is preferably connected in a conventional manner to a driving device (not shown) which works to pivot the second pivot shaft 44 about its axis 24. Various types of driving devices exist which are well-known to those skilled in the art and which can be used to pivot the second pivot shaft 44. Examples of such driving devices include actuators (air, fluid, etc.), solenoids (fluid, electric, electro-magnetic, etc.) and motors. However, for applications where the separation finger 12 must be moved into and out of place rapidly, an air actuator is preferred. Such an actuator is described in the Couturier patent mentioned above, the teachings of which are incorporated herein by reference insofar as they relate to shaft actuators and related mechanisms. One having skill in the art will recognize that a number of systems, assemblies, and devices (and their associated equipment) can be used to turn the second pivot shaft 44. Each of these other systems, assemblies, and devices falls within the present invention.

In operation, each separation finger apparatus 10 (remembering that there typically exists a series of separation fingers 12 extending into the plane of the page of FIG. 4) is in its retracted position shown in solid lines on FIG. 4. At a desired time, which can correspond to the completion of a stack S built upon a stack building surface A, the driving device connected to the second pivot shaft 44 is activated. This activation can be performed for example by a system controller, by a signal sent from one or more sensors monitoring the stack building process, or even manually. Such activation"triggers"are well-known in the art and depend largely upon the particular system design and use. Upon being activated, the driving device turns the second pivot shaft 44 about its axis 24, thereby exerting a rotational force upon the pivot arm 20 attached to the second pivot shaft 44. As the pivot arm 20 is rotated, it exerts a force upon the translation block 26, which reacts by translating or sliding along the translation shafts 14. The motion of the translation block 26 causes the translation shafts 14 to pivot about the first axis 16 as the translation block 26 travels along the length of the translation shafts 14. The translating or sliding motion of the translation block 26 and the rotational motion of the side shafts 14 about the first axis 16 generates an arcuately-shaped movement of the separation finger 12 attached to the translation block 26. This movement can be seen in the arrow labeled B on FIG. 4, which shows the progressive movement of the tip of the separation finger 12 as the separation finger 12 travels between the retracted and extended positions.

It can be seen from the motion of the separation finger 12 in FIG. 4 that the separation finger 12 can extend fully across the stack-building surface A upon which stacks of product are built. This provides the advantage of eliminating the need for two separation fingers 12 (one on either side of the stack-building surface S) to extend across the stack-building surface A. Thus, system design is simplified and system costs are lowered.

Also, by virtue of the arcuate motion of the separation finger 12, the amount of interference with the folding rolls 6,7 is lowered significantly. In particular, and for purposes of illustration in FIG. 4, the groove depth necessary for the separation finger design illustrated in FIG. 1 is shown on FIG. 4 as the dotted circle labeled C, while the groove depth necessary for the separation finger design of the present invention is shown on FIG. 4 as the dotted circle labeled D. Clearly, by avoiding a circular path of the separation finger 12 as is found in the prior art, the arcuate motion of the separation finger 12 in the present invention permits the separation fingers 12 to be brought close to the folding rolls 6,7 while creating less separation finger-to-roll interference and therefore, requiring less groove depth within the folding rolls 6,7. As a result, the rolls 6,7 are stronger, and (because roll runout from higher speeds is lowered due to stronger rolls 6,7) can be run at higher speeds or be made longer if desired.

In addition to the above-noted advantages realized by the present invention, the separation finger 12 is better adapted to be inserted within a stream of web product emitting from between the folding rolls 6,7. It can be seen from FIG. 4 that the separation finger 12 falls as it is moved from its retracted position to its extended position. As opposed to a number of prior art finger insertion mechanisms which quickly and directly insert fingers horizontally into the stream of web material, the separation finger 12 in the present invention falls with the stream of web material as it is inserted. This motion is gentler on the web material, and permits very light and delicate web material to be processed and stacked in the system. Especially where web material is used which is easily punctured or ripped (e. g., foils, tissues, etc.), the inserting and falling motion of the present invention provides significant advantages over the prior art.

A second preferred embodiment of the present invention is illustrated in FIG. 3. The separation finger 112 of the second preferred embodiment is substantially the same as the separation finger 12 of the first preferred embodiment, with the exception of the differences described below.

Where high-speed system operation is a necessity, one significant problem which arises involves the related factors of system weight and inertia. In particular, higher web stream speeds require faster separation finger speeds. Among other design challenges which arise from the need for faster separation finger speeds, the weight of the separation finger apparatus 110 presents difficulties in accelerating and decelerating the separation finger 112 during separation finger insertion and retraction operations. In short, the heavier the separation finger apparatus 110 is, the higher the torque necessary to accelerate the separation finger to the necessary speed and the greater the impact which is created once the separation finger reaches the end of its stroke. Both results are undesirable and are addressed by the design of the second preferred embodiment.

In order to reduce the weight of the separation finger apparatus 110, the translation shafts 14 and the clamp mount design of the pivot head 38 of the first preferred embodiment is replaced by an elongated finger guide 114. The finger guide 114 has an elongated hole 115 passing therethrough which runs a substantial length along the finger guide 114. At one end of the finger guide 114 is located a second hole 140 through which the first pivot shaft 142 passes. Although the finger guide 114 is prevented from movement along the first pivot shaft 142 by rings 139 flanking the finger guide 114 and secured to the first pivot shaft 142 in a conventional manner, the finger guide 114 is free to rotate about the first pivot shaft 142.

The translation shafts 14 of the first preferred embodiment and the finger guides 114 of the second preferred embodiment function in much the same way. Both are translational or slide members which are configured (preferably elongated) to permit the separation finger 12,112 to translate or slide therealong, whether via a translation block 26 or otherwise. Both are mounted for rotation about an axis 16,116, which can be the central axis of a pivot shaft 42,142. It will be appreciated that a number of other elements can perform these functions, the two described and shown herein serving to illustrate two preferred examples of such a member.

Additional weight is also removed from the separation finger apparatus 110 by the removal of the translation block 26 of the first preferred embodiment. The separation finger 112 has a fitting 113 which is engaged within the elongated hole 115 in the finger guide 114.

The fitting 113 has a flat upper surface and a flat lower surface which respectively face the interior upper and lower surfaces of the finger guide hole 115 and therefore prevent the separation finger 112 from rotating with respect to the finger guide 114. The fitting, 113 also has a flange 117 which maintains the fitting 113 and the separation finger 112 within the finger guide 114. It will be appreciated by one having ordinary skill in the art that different elements can be used to secure the finger guide 114 against axial movement along the first pivot shaft, to guide the fitting 113 and the separation finger 112 within the finger guide 114 without permitting rotation of the separation finger 112 therein, and to keep the separation finger 112 within the finger guide 114. For example, the separation finger 112 can have a raised rib (not shown) which fits within the elongated hole 115 in the finger guide 114, or can have a pair of pins (not shown) spaced apart and fitted within the elongated hole 115. The rib can have a bend or the pins can have heads to keep the separation finger 112 within the finger guide 114. Such alternate designs all share the common function of guiding the separation finger 112 within the finger guide 114 while preventing the separation finger 112 from rotating therein or from becoming disconnected from the finger guide 114. These alternate designs fall within the present invention.

It should be noted that the pivot pin 136 connection between the pivot arm 120 and the separation finger 112 is substantially the same as that described above with reference to the first preferred embodiment of the present invention, with the only exception being the fact that the separation finger 112 is located between the finger guide 114 and the pivot arm 120.

To further reduce the weight of the separation finger apparatus 110, holes 111 can be made in the separation finger 112 at locations where an excess of material is determined to exist. Also, since the primary loading force supported by the separation finger 112 is typically in the vertical direction, the separation finger 112 can be made relatively thin, with the necessary strengthening material for the separation finger 112 being located in the plane of the separation finger 112.

The various elements making up the separation finger apparatus 110 of the second preferred embodiment are preferably made from the same materials as those discussed in the first preferred embodiment described above and illustrated in the drawings. However, due to the replacement of the translation shafts 14 with the finger guide 114, it is possible to use different material for the finger guide 114 (rather than a heavy material such as steel). The finger guide 114 is preferably made from an engineered plastic or an ultra-high molecular weight (UHMW) material.

Though physically different from the first preferred embodiment in the ways described above, the second preferred embodiment of the present invention operates in substantially the same way to achieve the same advantages and results as described in connection with the first preferred embodiment. The separation finger apparatus 110 acts to preferably simultaneously translate and rotate the separation finger as it is inserted into or removed from a stream of web product. The separation finger apparatus 110 permits finger insertion fully across a stack-building station close to the folding rolls, (eliminating the need for a pair of fingers to perform this function), does so with much lower finger-to-roll interference than the systems and devices of the prior art to thereby avoid sacrificing roll strength and speed capabilities, and provides a simpler and more cost-effective design than in prior art systems and devices.

In yet another alternative embodiment of the present invention (not shown), the preferred embodiment illustrated in FIGS. 1 and 2 and described above is modified to further reduce the weight and resulting inertia of the apparatus. In this alternative embodiment, one of the two translation shafts 14 is removed, and the apparatus is left only with one translation shaft 14 along which the translation block 26 moves. Although the preferred embodiment of FIGS. 1 and 2 is preferred from the standpoint of system stability, substantially the same system with only one translation shaft 14 can be used, particularly where the other elements of the apparatus (such as the pivot arm 20 and pivot head 38) are adequately mounted to prevent significant movement of the apparatus along or parallel to the axes of the apparatus.

To help prevent such movement or"twist"of the translation shaft 14 with respect to the translation block 26, the cross-sectional shape of the translation shaft 14 and the matching shape of the hole 28 in the translation block 26 are preferably selected to resist turning of the translation shaft 14 in the hole 28. This shape can be square, hexagonal, triangular, rectangular, star or X-shaped, and the like.

A third preferred embodiment of the present invention is illustrated in FIGS. 5 and 6.

The third preferred embodiment of the present invention is a separation finger apparatus (indicated generally at 210) also capable of movement which is neither purely linear nor purely rotational. Specifically, the separation finger apparatus 210 preferably has a separation finger 212 directly or indirectly coupled to a cam follower 214 which is itself mounted for rotation about a first axis 216. In some preferred embodiments, the separation finger 212 is integral with or mounted to the cam follower 214 at a first end 221 of the cam follower 214 in any manner such as those described above with regard to the first and second preferred embodiments. More preferably however, the separation finger 212 is connected instead to a first pivot member 236. The first pivot member 236 is preferably a tube upon which the cam follower 214 is also mounted, and will be described in more detail below.

The separation finger 212 can be connected to the first pivot member 236 in any number of conventional manners, including without limitation by welding or brazing, by press or interference fitting, by one or more conventional fasteners such as bolts, screws, pins, and the like, by adhesive or cohesive, or by a threaded connection. However, in those preferred embodiments where the separation finger 212 is connected directly to the first pivot member 236, the separation finger 212 is preferably clamped thereupon by a conventional splint clamp tightenable by one or more threaded fasteners (not shown). Specifically, the separation finger 212 can have a split base through which the threaded fasteners can be passed to tighten the base upon the first pivot member 236. The separation finger 212 can be fastened to its base in any conventional manner (such as by conventional fasteners 255 as shown in the figures), or can be integral therewith as desired.

A pivot arm 220 and the first end 221 of the cam follower 214 are preferably attached to the first pivot member 236. The pivot arm 220 has a second end 222 preferably mounted for rotation about a second axis 224. Preferably, a second pivot member 211 is rotatable about the second axis 224, Also preferably, the pivot arm 220 is rotatably coupled to the first pivot member 236.

A driving device 246 (e. g., an actuator, a solenoid, etc.) is preferably rotatably coupled to the second pivot member 211 by way of a moment arm 245. As the driving device 246 rotates the moment arm 245 the pivot arm 220 is rotated about the second axis 224. Rotation of the pivot arm 220 causes the cam follower 214 and subsequently the separation finger 212 to move relative to the second axis 224.

Preferably, the cam follower 214 has a second end 238 which is guided by at least one surface of a cam member 226. The surface (s) of the cam member 226 can be one or more exterior surfaces, surfaces defining the interior of an aperture, and the like. Accordingly, the cam follower 214 can travel upon or within the cam member 226. As shown in FIGS. 5-8, the cam follower 214 most preferably moves along an aperture 240 in the cam member 226.

The shape of the aperture 240 defines how and to what degree the cam follower 214 will rotate about the first axis 216 as it orbits about the second axis 224. In this regard, the aperture 240 (or other surface guiding the cam follower 214) can be straight, bent, curved, angled, and the like. More preferably however, the aperture 240 is a curved aperture. The cam member 226 guides the motion of the cam follower 214 and subsequently the separation finger 212 so that the separation finger 212 moves along a non-circular and a non-linear path.

The separation finger apparatus 210 can therefore rotate about a first pivot point located at or near the first axis 216 as it orbits about a second pivot point located at or near the second axis 224, thereby causing the separation finger 212 to move along a curved path as the cam follower 214 is directed along a similarly curved aperture 240 of the cam member 226.

In order to better facilitate movement of the cam follower 214 with respect to the cam member 226, the cam follower 214 preferably has an extension 247, which can be connected to or be integral with the cam follower 214. More preferably, the extension 247 is located on the second end 238 of the cam follower 214. In one embodiment, the extension 247 is rotatably coupled to a friction reducing member 248 (described in greater detail below). The friction reducing member 248 rides along the curved aperture 240 of the cam member 226.

This relationship and movement of elements in the third preferred embodiment of the present invention permits the separation finger 212 to move in a non-circular and a non-linear path. In particular, the separation finger 212 moves in a curved path as it travels toward and away from a stream of web product exiting from the folding rolls 206,207. The separation finger 212 rotates about the first axis 216 as the second end 238 of the cam follower 214 travels along the preferably curved aperture 240 of the cam member 226, which causes the separation finger 212 to move toward and away from the stream of web material exiting the folding rolls 206,207.

Looking now to the separation finger apparatus 210 of the illustrated third preferred embodiment in more detail, it should be noted that the separation finger 212 is preferably a thin elongated member which is of sufficient length to underlie substantially the entire width of a stack of product. This avoids the expense and complexity of two separation fingers 212 extending and meeting each other from opposite sides of the stack. However, in some embodiments of the present design two separation fingers 212 extending and meeting each other from opposite sides of the stack can be utilized.

The separation finger 212 preferably has a splint clamp base for attachment to the first pivot member 236 as described in more detail above. Where the separation finger 212 is attached to the first pivot member for rotation therewith (such as when a splint clamp base is employed as just described), the first pivot member is rotatably connected to the pivot arm 220. In other embodiments, the separation finger 212 is attached to the cam follower 214 at the first end 221 of the cam follower 214. In these other embodiments, the first pivot member 236 can be connected to the pivot arm 220 with or without the ability to rotate with respect to the pivot arm 220. For ease of part replacement and maintenance, it is desirable to releasably attach the separation finger 212 to the first pivot member 236 or cam follower 214 with releasable fasteners. However, it is possible to make the separation finger 212 integral with the first pivot member 236 or with the cam follower 214. Alternatively, these elements can be permanently joined in any conventional manner (such as by welding, brazing, riveting, or gluing).

In those embodiments where the separation finger 212 is directly attached to the cam follower 214, the separation finger 212 need not necessarily be mounted to the cam follower 214 near the pivot member 236 as shown in the figures. Instead, the separation finger 212 can be mounted at another location along the cam follower 214, if desired.

The separation finger 212 can be any shape extending from the first pivot member 236 and/or cam follower 214, and is preferably relatively thin and lightweight. Most preferably, the separation finger 212 is elongated as shown in the figures.

To further reduce the weight of the separation finger apparatus 210, apertures (not shown) can be made in the separation finger 212 and the pivot arm 220 at desired locations.

Also, since the primary loading forces upon the separation finger 212 and the pivot arm 220 are typically in the vertical direction, the separation finger 212 and the pivot arm 220 can be made relatively thin, with the necessary strengthening material for the separation finger 212 and the pivot arm 220 being located in the plane of each element.

In the preferred embodiment illustrated in FIGS. 5-8 the cam member 226 has a curved aperture 240. The second end 238 of the cam follower 214 travels along the curved aperture 240 of the cam member 226, the curved aperture 240 guiding the motion of the cam follower 214 so that the second end 238 of the cam follower 214 moves along a curved path.

As noted above, other relationships between the cam member 226 and cam follower 214 are possible and fall within the spirit and scope of the present invention (e. g., employing or not employing a cam member aperture 240, having different surface shapes, etc.).

The aperture 240 can be a groove in a surface of the cam member 226 or can pass through the cam member 226, and is preferably shaped to receive the extension 247 therein for movement therealong. Alternatively, the second end 238 of the cam follower 214 can be shaped to be received within an aperture in the cam member 226, to ride upon a surface of the cam member 226 (such as, for example, a cam member surface facing substantially toward the cam follower 214 and against which the second end 238 of the cam follower 214 rides as it orbits about the second axis 224), and the like. In the extension and aperture connection of the illustrated preferred embodiment, the sides of the aperture 240 are relatively smooth and can be polished or finished in order to reduce friction between the aperture 240 and the second end 238 of the cam follower 214 or between the aperture 240 and the extension 247.

The aperture 240 can be any shape, but is preferably longer than it is wide.

In the illustrated preferred embodiment, the extension 247 of the cam follower 214 has a round cross section. However, in other embodiments the extension 247 can have a cross section which is any other shape (e. g., curved, elliptical, toroidal, square, etc.). The extension 247 preferably extends into the aperture 240 located in the cam member 226. The extension 247 thereby guides the rotational motion of the cam follower 214 in a path relative to the aperture 240 in the cam member 226. Preferably, the extension 247 is integral with the cam follower 214. However, in different embodiments the extension 247 can be coupled in a conventional fashion to the cam follower 214 (e. g., held by one or more conventional fasteners, press-fit, screwed into a mating threaded aperture in the cam follower 214, secured via cotter pins, clamped, welded, held via a bushing, and the like).

The relationship between the cam follower 214 and the cam member 226 described above can be reversed, if desired. Specifically, rather than have an aperture 240 in the cam member 226 within which the cam follower 214 (or an extension 247 thereof) is received, the cam follower 214 can have the aperture within which the cam member 226 (or an extension thereof) is received. For example, the cam follower 214 can travel along a rib, post, pin, or other protrusion (not shown) on the cam member 226.

One having ordinary skill in the art will appreciate that many other types of connections between the cam member 226 and the cam follower 214 can be employed that permit one or more surfaces of the cam follower 214 (or extension thereof) to be guided upon or by one or more surfaces of the cam member 226 (or extension thereof) as the cam follower 214 orbits about the second axis 224. By way of example only, the cam follower 214 can have a post, dimple, rib, or other protrusion received within and movable along a recess defined by one or more walls or other protrusions extending from the cam member 226.

Preferably, the protrusion can be straight, but is more preferably curved. As another example, the cam member 226 or an extension thereof can ride along a wall, ridge, lip, or other protrusion or extension of the cam member 226. The wall, ridge, lip, or other protrusion or extension can be straight, curved, or have any other shape desired, but in each case provides a face along which the cam follower 214 or extension thereof is guided while orbiting. In yet another example, the cam member 226 and cam follower 214 are connected by a track or rail permitting movement of the cam follower 214 with respect to the cam member 226. The track or rail can be straight, curved, or take any other shape desired for producing the desired rotation of the cam follower 214 during its orbiting movement. Still other connections between the cam follower 214 and cam member 226 are possible and fall within the spirit and scope of the present invention.

In embodiments in which the second end 238 of the cam follower 214 has an extension 247, the extension 247 preferably has smooth lateral surfaces. With reference again to the preferred embodiment illustrated in FIGS. 5-8, the extension 247 is preferably smaller in diameter than the width of the curved aperture 240 of the cam member 226 and is movable along the curved aperture 240. As the extension 247 moves along the length of the curved aperture 240, the second end 238 of the cam follower 214 is caused to traverse a similarly curved path, which in turn causes the separation finger 212 to travel along a curved path.

In the third preferred embodiment and in any of the above-described alternative embodiments thereto, a friction-reducing element 248 (such as a roller bearing, a needle bearing, a ball bearing, a polished insert, a low-friction sleeve or strip, a pin, a bushing and the like) can be employed between the cam follower 214 and cam member 226 to enable smoother relative movement of these elements. The friction-reducing element 248 can have any shape (e. g., ovular, elliptical, circular, square, etc.), dependent at least in part upon the type of bearing used and the manner in which it is connected to the cam follower 214 or cam member 226. In the illustrated preferred embodiment of FIGS. 5-8, the friction-reducing element 248 can be an annular bearing fitted upon the cam follower 214 or extension 247 and having an outside diameter slightly less than the inside diameter of the curved aperture 240 to reduce interference between the friction-reducing element 248 and the curved aperture 240.

Alternatively, the friction reducing element 248 can be one or more low-friction strips on the walls of the curved aperture 240, a sleeve of low-friction material on the cam follower 214 or extension 247 thereof, and the like. The friction reducing element 248 can be removably coupled to the second end 238 of the cam follower 214 and/or the cam member 226 in order to better facilitate replacement of the friction reducing element 248.

Because a number of friction-reducing element types result in rolling contact between the cam follower 214 and the cam member 226, the term"cam"used herein and in the appended claims in its various forms for describing the relationship between the cam follower 214 and the cam member 226 is understood to encompass such a physical relationship between these elements (as well as a sliding relationship and a combined rotating and sliding relationship). In this regard, these elements are considered to be in"camming"relationship with respect to one another even though the cam follower 214 has no direct contact with the cam member 226, but is guided thereby and separated therefrom by a friction-reducing element 248.

In embodiments in which it is present, the curved aperture 240 in the cam member 226 guides the movement of the cam follower 214. The curved aperture 240 preferably guides the cam follower 214 so that it does not move any more closely to the folding rolls 206,207 or any further from the folding rolls 206,207 than intended. Depending upon the orientation of the separation finger apparatus 210 and its various elements, it may only be necessary to limit movement of the cam follower 214 in one direction via the cam member 226, while movement of the cam follower 214 in another or opposite direction is limited by gravitational force, force from one or more biasing springs connected to the cam follower 214 or separation finger 212, and the like. As described above, the cam follower 214 in such embodiments need not necessarily be guided by multiple surfaces such as those of the illustrated curved aperture 240, and can be guided by as few as one surface.

It should be noted that the terms"translate"and"slide"and their various forms are used herein interchangeably. Both terms encompass any relationship between the cam follower 214 and the cam member 226 (or other comparable elements as discussed herein) which permits one of the two elements to move in a manner which is not exclusively rotational or pivotal with respect to the other. Such movement can include a rotational component, can be a path that is not straight (e. g., an arc-shaped path), and includes without limitation movement of one of the elements through, along, beside, toward, or away from the other element. For example, the cam follower 214 translates in the arc-shaped aperture 240 in the cam member 226, and preferably simultaneously rotates therein.

Additionally, the terms"translate"and"slide"encompass alternative relationships such as where the extension 247 is fitted with a friction reducing element 248 which itself slides along the arcuately-shaped aperture 240, where the movement of the cam follower 214 with respect to the cam member 226 is neither purely rotational nor purely non-rotational, where little to no physical contact occurs between the cam follower 214 and the cam member 226 (such as in fluid bearings, with a magnetic or electromagnetic field causing the friction-reducing element 248 to"float" within the curved aperture 240), where one or more rollers or casters between the cam follower 214 and the cam member 226 define rolling motion between the elements, and the like. All such manners of permitting relative and non-exclusively rotational movement between the cam follower 214 and the cam member 226 fall within the spirit and scope of the present invention.

In some embodiments, the cam follower 214 can be fixed (e. g., welded, pinned, screwed, clamped, pressed, and the like) to the first pivot member 236 so that when the first pivot member 236 rotates about the first axis 216 the cam follower 214 is caused to similarly rotate about the first axis 216. In this embodiment, the first pivot member 236 is rotatably coupled by a clearance fit, a bushing, a bearing, or in any other conventional manner to the pivot arm 220. Therefore, as the pivot arm 220 rotates about the second axis 224, the first pivot member 236 is caused to orbit about the second axis 224.

In other preferred embodiments, the first pivot member 236 is fixed to the pivot arm 220 (e. g., welded, pinned, screwed, clamped, pressed, and the like). In such embodiments, the first pivot member 236 is rotatably coupled to the cam follower 214 by a clearance fit, a bushing, a bearing, or any other conventional manner, while the separation finger 212 is connected to the cam follower 214 for movement therewith. Therefore, when the pivot arm 220 rotates about the second axis 224, the first pivot member 236 is caused to orbit about the second axis 224. While the first pivot member 236 orbits about the second axis 224, the cam follower 214 and the separation finger 212 attached thereto is caused to move toward and away from the folding rolls 206,207 while rotating with respect to the first pivot member 236.

In still other preferred embodiments, the first pivot member 236 is coupled to both the pivot arm 220 and the cam follower 214 for rotation with respect to both elements. In these embodiments, the separation finger 212 is attached to the cam follower for movement therewith. The cam follower 214 and the pivot arm 220 are both free to rotate about the first axis 216 regardless of whether or not the first pivot member 236 rotates about the first axis 216. However, when the pivot arm 220 rotates about the second axis 224, the first pivot member 236 is caused to orbit about the second axis 224. Consequently, the cam follower 214 is caused to move toward and away from the folding rolls 206,207 while rotating with respect to the first pivot member 236.

In each of the embodiments just described, the cam follower 214 (and separation finger 212) is rotatable about the first axis 216, whether accompanied by rotation of the first pivot member 236 or not. The pivot arm 220 can be rotatable with respect to the first axis 216 (in which case the cam follower 214 is mounted to the first pivot member 236 for rotation therewith and the separation finger 212 is mounted to the cam follower 214 and/or to the first pivot member 236 for rotation therewith) or can be attached to the first pivot member 236 without the ability to rotate with respect thereto (in which case the cam follower 214 is mounted for rotation with respect to the first pivot member 236 and the separation finger 212 is mounted to the cam follower 214).

The first and second pivot members 236,211 preferably have cylindrical cross sections but can have any other cross section desired capable of permitting the relative motion of the cam follower 214, first and second pivot members 236,211, and pivot arm 220 just described. In different embodiments, the first and second pivot members 236,211 can be made from tubes, shafts, or any other preferably elongated elements having any cross sectional shape.

In addition, the first and second pivot members 236, 211 are preferably made of material particularly resistant to buckling, capable of withstanding relatively high rotation speeds, frequent braking, and potentially large internal forces. In one highly preferred embodiment, the first and second pivot members 236,211 are made of composite tubing. In other preferred embodiments, the first and second pivot members 236, 211 are made of other materials, including without limitation steel, aluminum, iron and other metals, plastic, fiberglass, composites, refractory materials, and the like.

In one embodiment, the first pivot member 236 can be coupled to only one pivot arm 220 and one cam follower 214. However, in other preferred embodiments, the first pivot member 236 is coupled to multiple pivot arms 220 and/or multiple cam followers 214 in order to reduce material costs while enabling numerous separation fingers 212 to be coupled to a single apparatus. Most preferably, the separation finger apparatus 210 has a sufficient number of pivot arms 220 to support the first pivot member 236.

The first pivot member 236 is preferably coupled to a frame (not shown) in any conventional manner and can be coupled at one or both ends and/or at intermediate locations as needed. To permit the first pivot member 236 to orbit about the second axis 224 in such embodiments, the frame preferably has elongated apertures therein or has one or more tracks, guides, rails, or other supporting elements along which the first pivot member 236 can move so that the separation fingers 212 can still travel toward and away from the stream of web material exiting the rolls 206,207. Such structures can be used regardless of the number of pivot arms 220 and/or cam followers 214 used.

It should be noted that the present invention can be practiced with any number of cam followers 214, cam members 226, pivot arms 220, and separation fingers 212. Also, the first and second pivot members 236, 211 can be defined by multiple co-linear elements preferably acting in concert.

The first pivot member 236 is preferably secured for rotation with respect to the pivot arm 220 but not with respect to the cam follower 214 as described above. However, in those embodiments in which the first pivot member 236 is connected to the pivot arm 220 and is secured against rotation with respect thereto (also described above), such a connection can be made in a number of different conventional manners, such as via setscrews, pins, or bushings (not shown). Non-rotatable connection of the first pivot member 236 to the cam follower 214 can be made in the same manner. In one preferred embodiment, such non-rotatable connections to the first pivot member 236 are made by conventional splint clamps.

Preferably, the splint clamps are releasably tightenable to allow for maintenance, repair and adjustments.

The first pivot member 236 and the second pivot member 211 are preferably arranged in parallel relationship with one another. Like the first pivot member 236, the second pivot member 211 is preferably round in cross section but in other embodiments can be square, round, elliptical, hexagonal, or can have any other cross-sectional shape.

The second pivot member 211 is preferably secured to the pivot arm 220 for rotation therewith. The second pivot member 211 can be secured in a number of different conventional manners, such as via setscrews, pins, or bushings (not shown). However, pivot arm 220 is preferably connected to the second pivot member 211 via a conventional splint clamp on an end of the pivot arm 220. Preferably, the splint clamp is releasably tightenable to allow for maintenance, repair and adjustments.

Preferably, the single pivot member 211 is coupled to multiple pivot arms 220.

However, in some embodiments, the second pivot member 211 is coupled to one pivot arm 220. This can be done, for example, to reduce material costs or to simplify construction of the apparatus. The second pivot member 211 is preferably coupled to the pivot arm 220 so that when the second pivot member 211 is rotated, the pivot arm 220 is caused to similarly rotate about the second axis 224. The second pivot member 211 can be coupled to the pivot arm 220 by welding, clamping, screwing, pinning, compression fitting, brazing, and the like.

Instead of fixing the second pivot member 211 to the pivot arm 220, it may instead be desirable to make the second pivot member 211 and the pivot arm 220 from a single piece of material, removing the necessity for fixing these two elements together. Similarly, it may be desirable to make the cam follower 214 and the first pivot member 236 from the same piece of material, in which case the separation finger 212 can be connected to the first pivot member 236 or to the cam follower 214 for rotation therewith. Alternately, it may be desirable to make the pivot arm 220 and the first pivot member 236 from a single piece of material, in which case the separation finger 212 is attached to the cam follower 214 for rotation therewith. Finally, it may be desirable to make the pivot arm 220, the first pivot member 236, and the second pivot member 211 from a single piece of material, in which case the separation finger 212 is again attached to the cam follower 214 for rotation therewith.

As yet another alternative relationship between the second pivot member 211 and the pivot arm 220, the pivot arm 220 is pivotable with respect to the second pivot member 211.

In this embodiment, the pivot arm 220 is preferably directly or indirectly connected to a driving device 246 for actuation thereby. Alternately, the separation finger apparatus 210 in this case can be actuated by coupling a driving device 246 to the cam follower 214. In still another embodiment, the driving device 246 can be coupled to the first pivot member 236 for actuation thereof.

In the third preferred embodiment, a moment arm 245 is preferably coupled to the second pivot member 211. The moment arm 245 can be coupled to the second pivot member 211 by any of a variety of conventional methods, including without limitation welding, brazing, screwing, pinning, adhesives, compression fits, via bushings, set screws, or by one or more conventional fasteners such as bolts, internally-threaded fasteners, cotter pins, and the like. When the moment arm 245 is rotated about the second axis 224, the second pivot member 211 is caused to rotate about the second axis 224. In order to minimize apparatus cost and to ease assembly in some embodiments, the moment arm 245 can be integral with the second pivot member 211. However, for service and maintenance purposes, it is preferable that the moment arm 245 be releasably attached to the second pivot member 211.

A driving device 246 is preferably coupled to the moment arm 245 for actuation thereof. The driving device 246 can be coupled to the moment arm 245 in any conventional manner, such as by one or more fasteners, by a connecting rod, link, bar, or other element, and the like. The driving device 246 can actuate the moment arm 245 to rotate the second pivot member 211. Various types of driving devices well known to those skilled in the art can be used for actuating the assembly 210. Examples of such driving devices include without limitation conventional actuators (air, fluid, etc.), solenoids (fluid, electric, electro-magnetic, etc.) and motors. However, a pneumatic actuator is preferred. Such a driving device 246 is described in the Couturier patent mentioned above, the teachings of which are incorporated herein by reference insofar as they relate to shaft driving devices and related mechanisms.

One having ordinary skill in the art will recognize that a number of other systems, assemblies, and devices (and their associated equipment) can be used to turn the second pivot member 211. Each of these other systems, assemblies, and devices falls within the spirit and scope of the present invention. For example, a gear can be attached to the second pivot member 211 in any conventional manner and can mesh with another gear or a rack movable to generate rotation of the second pivot member 211. Therefore, the second pivot member 211 can be rotated utilizing a rack and pinion mechanism. As another example, the second pivot member 211 can be connected to a servo motor in any conventional manner for rotation thereby.

In alternative embodiments of the present invention, the driving device 246 can be connected to the cam follower 214 for direct actuation thereof. The driving device 246 in such cases is preferably connected to the cam follower 214 at or near the center of the cam follower 214 (although the driving device 246 can be connected to the cam follower 214 anywhere along the length thereof as desired). Where the driving device 246 is connected to the cam follower 214 for direct actuation thereof, movement of the driving device 246 causes the cam follower 214 to move through its arc-shaped path described above while the cam follower 214 is rotated by its relationship with the cam member 226.

As mentioned above, the cam follower 214 is preferably an elongated element attached to the first pivot member 236. In highly preferred embodiments, the cam follower 214 is preferably relatively wide at its first end 221 (allowing for a stronger connection with the first pivot member 236) and narrows toward its second end 238. In other embodiments of the present invention, the cam follower 214 is relatively narrow at the first end 221. A relatively narrow first end 221 minimizes potential interference with the folding rolls 206, 207 when the separation finger 212 and the first end 221 of the cam follower 214 are moved close to the folding rolls 206,207. Furthermore, because the first end 221 of the cam follower 214 can approach the folding rolls 206,207 more closely, a relatively shorter separation finger 212 can be used. Still other cam follower 214 shapes are possible and fall within the scope of the present invention.

In some highly preferred embodiments, the second end 238 of the cam follower 214 is shaped (e. g., rounded, blunted, sloped, and the like) to enable camming motion between of the second end 238 of the cam follower 214 and the cam member 226. Such a shaped second end 238 is particularly advantageous in embodiments in which the cam follower 214 directly contacts the cam member 226 as it moves (such as where an extension 247 of the cam follower 214 does not exist). The shaped second end 238 is preferably capable of traveling along the cam member 226 with minimal friction and consequently minimizes the power required to operate the separation finger apparatus 210.

Where a cam follower extension 247 is not employed (where camming action occurs between the cam follower 214 and the cam member 226 without an extension 247 as described above), the second end 238 of the cam follower 214 can still be provided with a friction-reducing element to enable smooth camming motion. Such a friction-reducing element can be any of those described above with reference to the cam follower extension 247, such as a conventional bearing, low-friction material strips, and the like. The friction- reducing element can be coupled to the cam follower 214 in any conventional manner including without limitation by being welded, received within an aperture within the cam follower 214, press fit onto the cam follower 214, and the like. Depending upon where the cam follower 214 cams against the cam member 226, the friction-reducing element can be located anywhere on the cam follower 214.

The first pivot member 236 is preferably coupled to the cam follower 214 at or near the first end 221 of the cam follower 214. In such embodiments, the cam follower 214 and the cam member 226 interact to at least partially control the angular orientation of the separation finger 212 in its movement toward and away from a stacking building area 255. In other embodiments, the first pivot member 236 is coupled to the cam follower 214 at a mid portion of the cam follower 214 or even near the extension 247 of the cam follower 214. The separation finger apparatus 210 of these alternative embodiments still operate under the same general principals described above. One having ordinary skill in the art will appreciate that the cam follower 214 can take any desired shape and can be connected to the first pivot member 236 at virtually any location on the cam follower 214.

In order to reduce the mass of the cam follower in some highly preferred embodiments, the cam follower 214 can have apertures therein. The apertures can be any shape and size desired, and can be located in various positions on the cam follower 214. The apertures serve to reduce the weight of the cam follower 214 while not significantly reducing the load bearing capacity or significantly compromising cam follower strength.

As described above, the cam follower 214 is coupled to the first pivot member 236 either for rotation therewith or for rotation with respect thereto (in different preferred embodiments) and can be coupled to the first pivot member 236 in any desired location on the cam follower 214 (but preferably on the first end 221 thereof). For example, in the illustrated preferred embodiment, the first end 221 of the cam follower 214 preferably has a hole therethrough of sufficient size and shape for receiving the first pivot member 236. In this embodiment, the first end 221 of the cam follower 214 is secured to the first pivot member 236 for rotation with respect thereto while the separation finger 212 is attached to the first pivot member 236 for rotation therewith adjacent to the cam follower 214 as shown in FIG. 5 (or is attached directly to the cam follower 214 in other embodiments). As mentioned above, the cam follower 214 can be secured to the first pivot member 236 in a number of different manners well known to those skilled in the art (such as via setscrews, pins, bushings, and the like). However, the first end 221 of the cam follower 214 preferably has a conventional splint clamp releasably attached to the first pivot member 236. In other preferred embodiments of the present invention, the first pivot member 236 is coupled in any conventional manner (e. g., welded, brazed, fastened via conventional fasteners, clamped, and the like) to any portion of the cam follower 214.

The various elements of the separation finger apparatus 210 described above and illustrated in the drawings, including the cam follower 214, the cam member 226, the separation finger 212, the pivot arm 220, the extension 247, and the moment arm 245 are preferably made of one or more strong and resilient materials. Such materials include without limitation steel, aluminum, iron and other metals, plastic, fiberglass, composites, refractory materials, and combinations thereof. Most preferably however, these elements are made from aluminum. It should also be noted that the cam follower 214 can be made from a tube, a shaft, a hollow member, a plate, rolled stock, or any other element otherwise having any cross sectional shape.

When installed within a system as shown in FIGS. 7 and 8, the separation finger apparatus 210 is preferably placed at a lower elevation than the folding rolls 206,207 such that the separation finger 212 assumes a place beneath the nip 208 between the folding rolls 206,207 when the separation finger apparatus 210 is placed in its extended position shown in FIG. 8.

It should be noted that the separation finger apparatus 210 can be mounted in various operative locations within a system, depending upon the desired function the separation finger apparatus 210 is to perform during system operation. For example, the separation finger apparatus 210 can be mounted for movement with the surface upon which stacked product is built, or can be mounted directly to a frame of the machine. In the first example, the first and second pivot members 236, 211 are preferably mounted in a conventional manner upon part of the mechanism or system which moves as product items are stacked upon the stack-building surface. Thus, the first and second pivot members 236,211 move with the surface upon which product is stacked. In the second example, the first and second pivot members 236, 211 are preferably mounted in a conventional manner upon the frame of the machine in which the separation finger apparatus 210 is installed. In either case, the first and second pivot members 236, 211 can be mounted via bearings (not shown) located in desired locations on the pivot members 236,211 (such as on both ends of the pivot members 236,211), thereby keeping the pivot members 236, 211 in a preferably parallel relationship with respect to one another. Other manners of securing the pivot members 236,211 are well known to those skilled in the art and are not therefore discussed further herein.

As can be seen from FIGS. 7 and 8, with both pivot members 236,211 on the machine frame, on a carriage, or on another element or assembly within the machine, rotation of one pivot member 236, 211 preferably causes the other pivot member 236, 211 to rotate and the separation finger 212 to move via the cam follower 214 and cam member 226 connection.

Although rotation of either pivot member 236,211 about the second axis preferably causes the desired movement of the separation finger 212 through a range of positions between its extended and retracted positions shown in FIGS. 7 and 8, less torque is typically required to move the separation finger 212 by rotating the second pivot member 211. As such, the second pivot member 211 is preferably connected in a conventional manner to the driving device 246 which operates to pivot the second pivot member 211 about its axis 224.

In operation, each separation finger 212 and associated elements (remembering that there typically exists a series of separation fingers 212 extending into the plane of the page of FIGS. 7 and 8) have a retracted position such as that shown in FIG. 7. At a desired time, which can correspond to the completion of a stack built upon a stack building surface in the stack building area 255, the driving device 246 connected to the second pivot member 211 is preferably actuated. This actuation can be performed for example by a conventional system controller, by a signal sent from one or more conventional sensors monitoring the stack building process, or even manually. Such actuation"triggers"are well known in the art and depend largely upon the particular system design and use. Upon being actuated, the driving device 246 preferably turns the second pivot member 211 about its axis 224, thereby exerting a rotational force upon the pivot arm 220 attached to the second pivot member 211. As the pivot arm 220 is rotated, the cam follower 214 is moved, and translates, slides, rolls, or is otherwise guided along the cam member 226. The motion of the cam follower 214 along the cam member 226 preferably generates an arc-shaped and non-circular movement of the separation finger 212. This movement can be seen in the dotted line labeled B on FIG. 8, which shows the progressive movement of the tip of the separation finger 212 as the separation finger 212 travels between the retracted and extended positions.

It can be seen from the motion of the separation finger 212 in FIG. 8 and in comparison of FIGS. 7 and 8 that the separation finger 212 can extend fully across a stack-building surface upon which stacks of product are built in the stack building area 255.

Although arrangements with separation fingers 212 flanking the stack building area 255 can be employed, this embodiment provides the advantage of eliminating the need for two sets of separation fingers 212 to extend across a stack-building surface. Thus, system design is simplified and system costs are reduced.

Also, by virtue of the arcuate motion of the separation finger 212, the amount of interference with the folding rolls 206,207 is lowered significantly. In particular, a comparison of FIGS 1 and 8 shows the difference in the amount of separation finger-to-roll interference between the two designs. For purposes of illustration, the groove depth necessary for the separation finger design illustrated in FIG. 1 is shown on FIG. 8 as the dotted circle labeled C, while the groove depth necessary for the separation finger design of the present invention is shown on FIG. 8 as the dotted circle labeled D. Clearly, by avoiding a circular path of the separation finger 212 as is found in the prior art, the motion resultant from simultaneous rotation and translation of the separation finger 212 in the present invention permits the separation fingers 212 to be brought closer to the folding rolls 206,207 while creating less separation finger-to-roll interference and therefore, requiring less groove depth within the folding rolls 206,207. As a result, the rolls 206,207 are stronger, and (because roll runout from higher speeds is lowered due to the stronger folding rolls 206,207) can be run at higher speeds or can be made longer if desired.

In addition to the above-noted advantages realized by the present invention, the separation finger 212 is better adapted to be inserted within a stream of web product emitting from between the folding rolls 206,207. It can be seen from FIGS. 7 and 8 that the separation finger 212 preferably falls as it is moved from its retracted position to its extended position. As opposed to a number of prior art finger insertion mechanisms which quickly and directly insert fingers horizontally into the stream of web material, the separation finger 212 in the present invention falls with the stream of web material as it is inserted. This motion is gentler on the web material, and permits very light and delicate web material to be processed and stacked in the system. Especially where web material is used which is easily punctured or ripped (e. g., foils, tissues, etc.), the inserting and falling motion of the present invention provides significant advantages over the prior art.

The embodiments described above and illustrated in the drawings are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention as set forth in the appended claims.

For example, in the preferred embodiments of the present invention as described above, the second pivot shaft 44,144 or member 211 is preferably driven to drive the separation finger apparatus 10,110,210. However, it is possible to instead drive the separation finger apparatus 10,110,210 by driving the first pivot shaft 42,142 or member 236. In the first and second preferred embodiments described above, the translation block 26 or the separation finger 112 translates or slides down the translation shafts 14 or finger guide 114, respectively, thereby causing the translation shaft 14 or finger guide 114 and pivot arm 20,120 to rotate and move the separation finger 12,112 through its path. In the third preferred embodiment described above, the cam follower 214 is guided by the cam member 226, thereby causing the cam follower 214 and pivot arm 220 to rotate and move the separation finger 212 through its path. The first pivot shaft 44,144 or member 236, the second pivot shaft 42,142 or member 211, or even both can be driven if desired.

Also, it should be noted that for purposes of driving the separation finger apparatus 10,110,210, it is not necessary to clamp or fix the separation finger apparatus 10,110,210 for rotation with both pivot shafts 42,142 and 44,144 or members 236,211. In fact, the separation finger apparatus 10,110,210 in preferred embodiments need only be fixed for rotation with the pivot shaft 42,142,44,144,211 which drives the apparatus. The other pivot shaft acts to hold the remainder of the separation finger apparatus 10,110,210 in proper position as it passes through its range of motion. Therefore, the separation finger apparatus 10,110,210 need only pivot about the other pivot shaft rather than being clamped for rotation therewith. If other methods of driving the separation finger apparatus 10,110, 210 of the present invention are employed (which do not rely upon turning either pivot shaft 42,142, or member 211 but instead upon directly pushing or pulling other part (s) of the apparatus such as the pivot arm 20,120,220 or the separation finger 12,112,212), the separation finger apparatus 10,110,210 need not be fixed to rotate with either pivot shaft 42, 142,211. Instead, the separation finger apparatus 10,110,210 need only pivot about the pivot shafts 42,142,211.

Finally, it will be appreciated by one having ordinary skill in the art that a number of systems, devices, and mechanisms exist for absorbing system shock and for controlling the slowdown and stopping of the separation finger apparatus 10,110,210. Such systems, devices, and mechanisms can be employed with the present invention to control its shock and motion, and are particularly important as the speeds at which the present invention operate increase. Shock absorption and controlled slowdown systems are well-known the art, and can be valuable for extending the life of the separation finger apparatus 10,110,210 and the systems in which the present invention is installed.