APPARATUS FOR CUTTING FILM TUBING

FIELD OF THE INVENTION:

The present invention relates to the field of cutting mechanisms, and more particularly to cutting mechanisms adapted for cutting thin wall tubing in a tubular labeling machine.

BACKGROUND OF THE INVENTION:

Thin wall plastic tubing is often used for over-wrapping product containers, for example bottles containing personal hygiene, pharmaceutical or food products. In one form, the plastic tubing is applied as a label over a major portion of the container to identify the product and/or enhance the appearance of the container. In another form, the plastic tubing provides a tamper-evident band that covers the container cap and neck, serving to indicate whether the container has been opened prior to purchase. Identifying labels and tamper-evident bands are referred to collectively herein as tubular labels. In many cases the plastic tubing is processed so as to be shrinkable by the application of heat after a cut length of tubing has been placed over the container causing the tubing to conform snugly to the contours of the container.

The subject plastic tubular labels are applied to product containers in manufacturing environments, therefore process reliability, tubing length consistency, and neatness of the cut edge are important factors. Most known machines for the application of thin wall plastic tubing to containers employ a scissor-type double blade cutter or a guillotine-type single blade cutter. Another cutter type operates a number of rotatably mounted blades that are positioned around a central hole through which a tubular film is passed. The blades are caused to rotate after the film has been advanced a predetermined length.

One such cutter is described in U.S. Patent No. 5,531 ,858 entitled "Shrinkable Label Inserting Machine" in which the blades are mounted on a number of rotatable wheels that are in contact with a single driven band, e.g. a belt or chain, that drives all of the wheels.

A second such cutter is described in U.S. Patent No. 5,791 ,220 entitled "Cutting Device Of Packing Apparatus" in which the blades are mounted on a number of rotatable wheels that are in contact with one of a series of bands that drive each wheel in tandem.

A third such cutter is described in U.S. Patent No. 5,970,685 entitled "Cutting Mechanism For A Thermal Shrinking Film Labeling Machine" in which the blades are mounted on a number of electronic or hydraulic rotary tool holders that are adapted for rotating back and forth.

The present invention provides a unique film tubing cutter that employs a driving mechanism not disclosed in any known prior art and is described below.

The present invention cutter may also be used for cutting lengths of thin wall tubing that is formed substantially continuously by the process of extrusion. The resulting extruded tubing product is cut to defined lengths for packaging and shipping. The present invention is useful to cut lengths of tubing emerging from the extruding operation or subsequently in substitution for the current single blade cutting that is commonly used.

SUMMARY OF THE INVENTION:

The apparatus for cutting film tubing described herein utilizes a number of pinions that are rotatably mounted and equally spaced around a bore in a platform. A blade is assembled to each pinion and the pinions mesh with a central ring gear that is rotatably mounted on the platform coaxially with the bore of the platform. A film tube is passed through the ring gear and the platform bore. One of the pinions is driven by a motor through a single-revolution clutch. A series of bottles, or other products on which a tubular label is to be mounted, is transported on a conveyor to a location below the platform bore. As a bottle approaches a point in line with the center of the bore, a length of film tubing is advanced and the clutch is actuated to cause the pinions to swing the blades in synchronized arcs to sever a length of tubing that is then placed on the bottle. A

product conveyor is used if the cut tubing is to be placed over a bottle or other product, but not if the cutter is used for cutting lengths of tubing from an extruder.

BRIEF DESCRIPTION OF THE DRAWINGS:

The present invention is best understood in conjunction with the accompanying drawing figures in which like elements are identified by similar reference numerals and wherein:

Figure 1 is a schematic elevation view of a machine for applying tubular labels to containers transported on a conveyor including the cutting apparatus of a first embodiment of the present invention.

Figure 2 is a schematic plan view of the cutting apparatus of the present invention taken in the direction of line 2 - 2 of Figure 1 with the conveyor eliminated for clarity.

Figure 3 is a perspective view of a pinion with a disc and a blade assembled thereto according to a first embodiment of the invention.

Figure 4 is an exploded schematic elevation view of the cutting apparatus according to the first embodiment.

Figure 5 is an exploded schematic elevation view of the cutting apparatus according to a second embodiment of the invention.

Figure 6 is an assembled schematic elevation view of the cutting apparatus according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:

Referring to Figure 1, the machine 10 for applying tubular labels or tamper-evident bands to containers 62 advances a tubular film 22 in the direction indicated by arrow A from a film supply 20 by the intermittent action of driven wheels 30 in the direction indicated by arrow B. Driven wheels 30 are rotated by an actuator (not shown), for example a stepper motor. Driven wheels 30 and idlers 24 and 28 are mounted to a support (not shown) to define a path for advancing

tubular film 22 from supply 20 through a bore 38 in a platform 32. A spreader 26, as is known in the trade, is inserted into tubular film 22 between idler 24 and idlers 28 to open a cross fold tubular film 22 from the flattened condition on supply 20 to an opened condition. The apparatus 12 of the invention for cutting film tubing 22 is mounted to platform 32, and a conveyor 64 passes below platform 32 in the direction indicated by arrow C for carrying a series of spaced apart products or containers, for example bottles 62, to be labeled. Film tubing 22 is to be cut into selected length sleeves by blades 36a and 36d that are mounted respectively on pinions 34a and 34d. In practice, and as shown in Figure 2, more than two blades and pinions are used. Pinions 34a and 34d engage a ring gear 40 that is mounted on platform 32 in concentric relation to bore 38. A set of discs 42a and 42d are assembled to pinions 34a and 34d to prevent ring gear 40 from axial movement. Film tubing 22 is first held still and then discharged by a pair of drivers 44 as each bottle 62 is positioned to receive the sleeve label. As stated above, the cutter of the present invention is applicable to cut lengths of tubing from an extruding operation, in which case the conveyor is not needed. The present invention can also be employed with film tubing 22 being advanced horizontally to enwrap a horizontally oriented product with cutting mechanism 12 oriented vertically.

Referring now to Figure 2, platform 32 is formed with a bore 38 therethrough of sufficient diameter D to allow tubular film 22 to pass. A ring gear 40, formed with its central hole equal to or greater in diameter than bore 38 in platform 32, is mounted on platform 32 in a manner to enable free rotation thereof. A series of pinions 34a - 34f are mounted rotatably to platform 32 in angularly dispersed positions around ring gear 40 to mesh therewith. Each pinion 34a - 34f is assembled to a shaft, the shafts being perpendicular to the surface of platform 32. A selected number of planar members, for example discs 42a - 42f, are assembled coaxially to the upper surface of each respective pinion 34a - 34f. Discs 42a - 42f are preferably equal to or greater than pinions 34a - 34f in diameter to overlap at least the area occupied by the teeth of ring gear 40. Whereas the preferred embodiment is depicted in Figure 2 as having 6 discs, a lesser number of discs, e.g. 3 or 4 discs, would perform the essential function of maintaining ring gear 40 in position axially. The ring formed of pinions 34a - 34f

effectively radially captures ring gear 40 while discs 42a - 42f axially capture ring gear 40, allowing free rotation thereof while preventing significant movement in both thθ radial or axial directions. Depending on the materials of which pinions 34a - 34f and ring gear 40 are made and on the service requirements of the cutting apparatus, a bearing washer or gasket (not shown) may be assembled between each pinion and the respective disc. According to the preferred embodiment, no mounting bearings or retention clips are employed to support or restrain ring gear 40. Ring gear 40 is rotated by the action of pinions 34a - 34f. A series of blades 36a - 36f are affixed to the top surfaces of each of discs 42a - 42f. Blades 36a - 36f are preferably formed with elongate sharp cutting edges and angled tips, as is shown. The sharp elongate edges of blades 36a - 36f face the center of ring gear 40 when pinions 34a - 34f are in the rest position. Blades 36a - 36f are each mounted to respective discs 42a - 42f with their respective elongate cutting edges similarly oriented in respect to a radius of ring gear 40 in order that blades 36a - 36f are able to rotate in the same angular direction as indicated by arrow F, i.e. counterclockwise. The synchronized rotation and positioning of pinions 34a - 34f, discs 42a - 42f and blades 36a - 36f results in the tips of blades 36a - 36f following complementary, overlapping arcs as indicated by arrows E to intersect and cut tubular film 22 without interference from other blades. The preferred embodiment depicted herein has 6 pinions and 6 blades, but different numbers of pinions and blades are possible, with the pinion diameter and the blade length configured accordingly. In particular, the invention contemplates a lesser number of pinions and blades with a tubular film of smaller diameter, and vice versa. The pinions 34a - 34f and discs 42a - 42f are mounted an equal angular distance from each other. In order to maintain a precise orientation between the blades and the respective pinions to which they are mounted, discs 42a - 42f are preferably formed with a blade seat, or channel (not shown). Blades 36a - 36f are fastened into respective blade seats or anchored by fasteners for secure positioning. The invention disclosed further encompasses a configuration in which the illustrated assembly is inverted with blades 36a - 36f disposed beneath discs 42a - 42f and cutter mechanism 12 resides beneath platform 32.

Each pinion 34a - 34f is held in a stationary rest position between tubing cutting operations, as illustrated in Figure 2, with each respective blade 36a

- 36f residing substantially perpendicular to a radius of bore 38. The majority of pinions, specifically pinions 34b - 34f, are mounted to be freely rotatable with respect to platform 32 in a manner well known to those skilled in the art. A selected pinion, specifically pinion 34a, is mounted to a shaft that passes through platform 32 to terminate at a pulley 56 (Figure 1), preferably a timing pulley. Pulley 56 is drivingly connected by a belt 58, preferably a timing belt, to pulley 54, preferably a timing pulley. Pulley 54 is mounted to the shaft of a clutch 52 that is coupled to a motor 50. Motor 50 is of any known type of motor able to drive the mechanism described herein. Motor 50 operates continuously. Clutch 52 is of the type known as a single-revolution clutch/brake, available for example from Danaher Corporation of Washington, DC. The size and power ratings of motor 50 and clutch 52 are to be determined according to the requirements of the system being designed.

Referring again to Figure 1 , conveyor 64 operates continuously to convey a series of bottle 62 into position below the center of bore 38 in plate 32. As each bottle 62 approaches the desired position, a selected length of tubular film 22 is advanced by driven wheels 30 and is positioned above the projected location of container 62. Clutch 52 is activated by motor 50 to rotate through one revolution, causing pinion 34a to rotate one revolution, in turn causing pinions 34b

- 34f (Figure 2) to rotate one revolution through the counter rotation of ring gear 40 in the direction indicated by arrow G. Blades 36a - 36f are caused to rotate in unison through arcs E (shown in dashed lines) to cut through tubular film 22, separating the advanced length of tubing from tubular film 22 as a cut sleeve. A pair of film drivers 44 (Figure 1 ) reside downstream of blades 36a - 36f to hold each cut length of tubing film 22 suspended until a bottle 62 is properly positioned. Sensors (not shown) to detect the continuity of tubular film 22 and the position of bottle 62 are provided in the manner known in the trade. The sensors send responsive signals to a microprocessor (not shown) for control of the activation timing .of driven wheels 30, drivers 44 and clutch 52. The cut sleeve 22a is first held stationary and then discharged by drivers 44 when bottle 62 reaches the

selected position. The cut lengths of tubular film 22 are illustrated as sleeves 22a on bottles 62 that have been conveyed past the label mounting position. After clutch 52 causes blades 36a - 36f to cut tubular film 22, drivers 44 are activated to discharge the cut sleeve 22a onto bottle 62 and, simultaneously, driven wheels 30 are activated to advance a subsequent length of tubular film 22. Subsequent to assembling the cut sleeves 22a on bottles 62, bottles 62 are placed into an environment to cause the sleeves to shrink radially and snugly enwrap the bottles, for example a heat tunnel.

Referring now to Figure 3, a perspective view of a typical pinion 34f is shown with disc 42f and blade 36f mounted thereto. As briefly described above, the diameter d of disc 42f is equal to or greater than the diameter d' of pinion 36f. This diameter d provides that the gaps between the teeth of pinion 34f are covered by disc 42f. When assembled as shown in Figure 2, the teeth of ring gear 40 engage the teeth of pinion 34f and are covered by the extending portion of disc 42f. In this matter, disc 42f and additional discs mounted to several pinions axially capture ring gear 40 in close proximity to platform 32.

Referring now to Figure 4, the embodiment illustrated and described in relation to Figures 1 , 2 and 3 is shown in partially exploded schematic side elevation view. As described above in relations to Figure 3, a planar member, e.g. disc 42e is mounted by any appropriate means to pinion 34e, and blade 36e is mounted by appropriate means to disc 42e. A shaft 46e extends axially outward from the bore of pinion 34e for mounting into socket 48e in platform 32 to enable pinion 34e to rotate freely. A similar set of components 34b, 36b, 42b, 48b is shown in mirror image. Ring gear 40 is positioned to reside rotatably on platform 32 in coaxial alignment to bore 38. As described briefly above, when the cutting apparatus of the invention is fully assembled, with shaft 46e positioned in socket 48e, the teeth of pinions 34e, 34b engage the teeth of ring gear 40, and discs 42e, 42b prevent ring gear 40 from more than slight axial movement. As will be understood, the spacing of disc 42e from platform 32 controls the degree of axial movement possible by ring gear 40. While the cutting assembly is illustrated with blades 36e, 36b above platform 32, the invention contemplates mounting the

apparatus in reverse vertical positions so that blades 36e, 36b are below platform 32, depending on the needs of the operation for which it is used.

Referring now to Figure 5, a partial exploded schematic elevation view of a second preferred embodiment of the invention is shown. Blade 36e is assembled directly to the upper surface of pinion 34e with no intervening planar member. Ring gear 40 is assembled coaxially to an annular planar member, e.g. washer plate 66, being formed with a central bore therethrough of similar diameter to the bore through ring gear 40. Ring gear 40 is assembled to washer plate 66 by any appropriate means. Upon assembly, with the teeth of pinions 34e, 34b engaged with the teeth of ring gear 40, and shafts 46e, 46b held in sockets 48e, ,48b, portions of pinions 34e, 34b overlap the perimeter of washer disc 66 and prevent ring gear 40 from more than slight upward axial movement.

Referring now to Figure 6, a third preferred embodiment is shown in assembled side elevation view. An annular planar member, e.g. washer plate 70, formed with a central bore of similar diameter to the bore of ring gear 40, is mounted to platform 32 by fasteners F or other means passing through a series of supports 74. Supports 74 are of sufficient length to allow ring gear 40 to rotate freely and not move more than a slight amount in the axial direction. Supports 74 are positioned in locations on platform 32 to avoid interfering with pinions 34e, 34b and additional pinions as may be employed. Washer plate 70 is preferably round and of sufficient diameter to overlie an area where the teeth of ring gear 40 engage the teeth of pinions 34e, 34b to prevent more than minimal axial movement of ring gear 40. A series of blades 36e, 36b are mounted to respective pinions 34e, 34b through columns 76e, 76b so that blades 36e, 36b are able to rotate without interfering with washer plate 70.

While the description above discloses preferred embodiments of the present invention, it is contemplated that numerous variations and modifications of the invention are possible and are considered to be within the scope of the claims that follow.

What is claimed is: