CAM DEVICE FOR PRODUCING MULTIPLE SEQUENTIAL AND OVERLAPPED KNOTS, OF A DIFFERENT SIZE AND AT VARIABLE SPEED DESCRIPTION This invention refers to a cam and rocker arm device equipped with two perpendicular axles carrying a needle and crochet at their respective extremities, capable of producing multiple sequential knots, of a simple or overlapped type, of different size and at variable speed.

Such a device is generally employed for joining very thin paper layers (of a few tenths or hundredths of a millimeter) over a well defined stretch, and finds a particularly useful application in the manufacturing of filter bags for infusion products, where the top end of the filter bag, which is generally formed by thin paper layers folded over themselves must be firmly sealed so at to prevent the infusion material from escaping while dipped into boiling water, while at the same time said sealing devices also act as an anchor for the free end of a bag handling thread.

Some patents disclosures have existed for many decades, which suggest to fastening the layers of the filter paper forming the sealing lobe of a filter bag by a sealed or through knotting, so as to offer an alternative for the traditional and undesirable sealing systems of the filter bags employed for decades, such as metallic clips and thermoplastic stamps which are held to be a potential source of pollution of the infusion and susceptible of altering its organoleptic properties. In particular, the U. S. patent no.

2.307.998 of 1943 illustrates a type of sealed knotting always contouring the top end of the bag, while also describing a method of applying the proposed knot. While attributing the sealing of a filter bag by knots or some sewing points comparable to knots to a known technique, for the purposes of producing these knots the mentioned documents always refer to some known sewing devices, which have however always failed to find a practical industrial application in sealing a filter bag, for the simple reason that the productivity of the filter bag manufacturing machines is very high (about 200-300 bags per minute) and that the knotting operation of every single filter bag (for

every stop in the machine cycle) occurs within a few milliseconds, a fact which fails to guarantee a continuous execution of the knotting points.

Other methods and devices describing other special knotting points also exist, but all of them exhibit the characteristic of producing individual knots joining the paper layer in a single point, with the double drawback of failing to produce the knot if the thread is lost at that point, and of being unable of laying down an extended line of knots because of the impossibility of producing sequential knots, meaning one closely after another.

In addition to the mentioned drawbacks, the joining of multiple layers of filter paper in general and the sealing of filter bags in particular poses a number of other demands of an entirely different nature: the length of the linear stretch affected by the joining or sealing of the bag should, during its stop, require not one but two, three, four or more simple sequential knotting points, without affecting the productivity of the filter bags (Fig. 1); in addition to the length of the joining stretch, there is also the problem of the thickness to be sealed off, depending on the variable number of the layers of filter paper to be fastened or on the thickness of every single folded layer, which may make it necessary, for better assurance, to apply two, three, four etc. overlapped sequential knots, without affecting the productivity of the filter bags (Fig. 2); the layer of filter bag to be sealed may not be uniform due to the presence of intemal creases in the folds, such as in the case of double-lobe bags: it may in this case be necessary to apply a series of sequential knots, of a simple or overlapped type and of a different size so as to enable for instance the central knot, which is capable of fastening the stretch in a crease, to be larger with respect to the two knots immediately preceding and following it (Figure 3).

The purpose of this invention is to resolve all the mentioned problems with the required knotting flexibility, by using a mechanical cam and rocker arm device capable of deriving its motion directly from the manufacturing machine it is mounted on and of producing at each machine cycle, depending on the various layers of filter paper to be fastened and on the various lengths of the linear stretches to be sealed, a row of

multiple sequential knots, of a simple or overlapped type. of a different size and at variable speed, while foliowing the speed of the manufacturing machine to avoid affecting its productivity.

The mentioned purpose is achieved in accordance with the contents of this invention.

The characteristics of this invention are highlighted below, with reference to the attached figures, where: Figure 1 illustrates a row of three simple sequential knots of equal linear size (x=y=z).

Figure 2 illustrates a series of three double sequential and therefore overlapped knots of equal linear size (x=yz).

Figure 3 illustrates a series of three simple sequential knots of different linear size (a central knot larger than the two lateral knots) (x=y=z).

Figure 4 is a prospective view of the device, evidencing all its extemat operating organs.

Figure 5 is a ground view of the same device.

Figure 6 is a front view.

Figure 7 is a side view Figure 8 is a ground view with particular reference to the multiple swinging motions of the device.

Figure 9 is a particular front view showing the device s shearing characteristics.

Figure 10 is a front view with particular reference to the multiple swinging motions of the crochet's axle (3).

Figure 11 is a ground view with particular reference to the multiple swinging motions of the needle bar (4).

With reference to Figure 4, the number 1 indicates a mechanical box extending in a projecting fashion from a vertical operating plane and in its overall form constituting the device as an object of this invention. This device is essentially formed by three axles set in a mutually perpendicular position while at rest: a first axle (4) essentially coinciding with the needle bar which is perpendicular to a second axle (3) essentially

coinciding with the crochet carrying bar, which is in turn perpendicular to a third axle (2) constituting the inner shaft of the device acting as a fulcrum for all the mutually phased cams which provide the relative rotating and sliding motions to all the external organs defining the device (1).

With reference to the Figures 4 and 5, the number (26) (Fig. 5) indicates a general organ containing in its interior a needle bar (4) which carries a sewing needle (28) at its extremity (27). This needle bar (4) has the characteristic of being hinged at three main points (P1, P2 and P3), one of which is fixed (P1) and the other two are mobile (P2 and P3).

As a result of its intermittent angular displacement, the lever (24) actuated by a first cam mounted on the shaft (2) generates on the needle bar (4), through its fulcrum (P2) and while cooperating with the connecting rod (30), an intermittent vertical motion in an upward and upward direction, so that the extremity of the needle (28) is capable of cooperating, for the production of every knot, with the relative crochet (29). The lever (22) actuated by the second cam opposite P4 operates in cooperation with the connecting rod (20) hinged at the point P3 of the organ (26) and generates, as a result of rotating around the fulcrum (P4), a horizontal shift of the mentioned connecting rod (20), based on which the organ (26) rotating around its fixed fulcrum (P1) induces a swinging motion on the needle (28), which may, depending on the construction requirements, be of a sequential or multiple type or set at an a W ß differential angular distance (Fig. 8), while the layers of material (31) to be sealed or knotted remain fastened inside the containment hopper (21). Apart from the organs and movements described above, the device (1) is equipped with suitable means for the feeding and unwinding of an appropriate knotting thread (14) endowed with the necessary tension, which cooperates with the mentioned organs of the device (1) to produce the multiple sequential knots of different size. More specifically, the thread (14), which is fed by known devices not shown in the enclosed figures is first stretched by the thread tightener (32), so as to allow it to cross the two thread braking devices (15) and (16)

without breaking. The thread (14) subsequently crosses the fixed thread tighteners (17) and (18), as well as the mobile guiding slit (39) firmly attached to the bar (4) during its vertical motion, and is fed into the tube (19) essentially parallel to the bar (4), to be inserted first into the additional guiding slit (27) and finally into the eye of the needie (28). The thread braking devices (15) and (16) are capable of releasing and stretching some linear stretches of thread of different size for each multiple knotting cycle. The mentioned devices (15) and (16) are in fact actuated by two cams which are mutually phased with the second cam actuating the lever (22), which in turn generates the different and multiple shifts of the needle (28). It can be intuitively grasped at this point that as the needle must produce multiple sequential knots of a different size for each knotting cycle, the thread braking devices (159 and (16) must be capable of releasing the linear stretches of thread of a different size required by the needle from their stretched condition.

The Figures 4,6 and 7 provide a prospective, frontal and side view of another typical feature of the device (1): the entire crochet axle structure constituted by a series of fixed and mobile organs whose conjugate motion defines the innovative aspect of this invention. The crochet axle (3) in particular derives its rotating motion from a pair of conical gears (5) and (6) driven by the cam shaft (2). The mentioned axle (3) features a series of organs endowed with a conjugate motion between themselves, which allow them to perform some swinging sequential shifts of a different angular size, with a motion perfectly phased with the sequential angular shifts of a different size of the needle (28).

The axle (3) in particular is firmly attached to a bushing (8) connected by the fulcrum (34) to the mobile connecting rod (7), which takes its motion from the lever (23) through the fulcrum (25) (refer to Figures 4 and 5). This motion allows the axle (3) to glide inside an eyelet (33) provided in a fixed plane (9). More specifically, the lever (23) takes its motion for the angular shift from the fulcrum P4 and therefore transmits, operating in phase with the lever (22), a horizontal and intermittent linear motion to the connecting

rod (7), through the fulcrum (25),. The mentioned connecting rod (7) shifts the bushing (8), on which the axle (3) tums, by as many linear stretches as required to sequentially shift the crochet (29) in the eyelet (33) and to produce, in phase cooperation with the needle (28), a series of multiple sequential knots of different size. It should also be observed that the multiple angular shifting of the axle (3) is made possible by an oscillating bearing (40) (refer to Fig. 6) which generates, in cooperation with the rotating axle of the bar (3), an oscillating fulcrum P5 on whose center of gravity the crochet axle (3) swings during its angular shifts. The bars (3) and (4), which carry at their respective extremities a known rotating crochet and a known sewing needle, allow them to produce, when actuated by the conjugate motion of the levers (22), (23), (24) and a series of cams capable of impressing angular shifts of different size upon them, a series of sequential knots (Figures 6,8,10,11) on a material firmly set into the hopper (21), with the advantage of making it possible to change the number of knots produced in an overlapping fashion and the linear size of each knot (X differing from Y), simply by substituting the respecting control levers. It should be mentioned that the examples offered in the Figures 6,8,10,11 are, both in the number and the size of the knots produced, of a purely indicative nature and not binding for the purposes of the subsequent claims.

A further essential feature of the device (1) is constituted by the cutting device (10) shown in Figure 9, where said device acts in combination with the other organs described above.

The mentioned device (10) is actuated by the conjugate motion of the lever (12) and of the connecting rod (11), which take their motion from a further cam set on the shaft (2) that operates in phase synchronization with the preceding cams actuating the levers (22), (23) and (24) and their respective knotting organs. The mentioned thread shearing device (10), which faces the last knotting point among the sequential knots produced, takes care of cutting off the last stretch of thread (14) after the mentioned last stretch (37) of thread has been inserted into the opening (38) of the last loop (36)

of the knots produced. This makes it possible to firmiy retain the mentioned last stretch (Figure 3) in the last loop, which remains closed and locked for the subsequent traction, thus concluding the row of sequential knots.

The invention thus conceived and described above may be subject to numerus modifications, ail of which are however falling within the scope of the innovative concept.