EP1175344B1

EP1175344B1 - Cam device for producing multiple sequential and overlapped knots, of a different size and at variable speed

Info

Publication number: EP1175344B1
Application number: EP00917237A
Authority: EP
Inventors: Calogero Daunisi
Original assignee: Teamac Srl
Current assignee: Teamac Srl
Priority date: 1999-05-05
Filing date: 2000-04-25
Publication date: 2004-03-17
Anticipated expiration: 2020-04-25
Also published as: ITMI990976A1; EP1175344A1; DE60009053D1; WO2000068085A1; IT1312393B1; DE60009053T2

Description

This invention refers to a device capable of producing multiple sequential knots, of a simple or overlapped type, of different size and at variable speed, on sheets of material.

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.

One of these devices is disclosed in U. S. patent n° 2.690.723, on which the two-part form of claim 1 is based, concerning a device for zigzag sewing. This machine, however, is not apt to make knotting on fixed filter bags, and even in conjunction with a separate device that holds said bags, couild only make always the same knot with the same size. On the contrary, it is important to be able to make multiple and variable size knots, in function of specific requirements. Moreover the device of US 2.690.723 sews with two threads so, in case of loosing one thread, it isn't able to make the knot and the fact that it use two threads, instead one, decreases the reliability of the system.

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 internal 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 following 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=y=z).

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 external 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 essentially comprises 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 a set of 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 or support 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).

A lever (24) actuated by a first cam mounted on the shaft (2) is linked, by means of a connecting rod (30), having fulcrum in P2, to the needle bar (4) which can slide inside the support (26) so that the extremity of the needle (28) can cooperate with the relative crochet (29) in order to complete the knots. A second lever (22) having fulcrum in P4 and actuated by a second cam mounted on said shaft (2) is linked to the support (26) through a connecting rod (20), which in its turn is hinged at the point P3 of the support (26) and generates, as a result of its rotation around the fulcrum (P4), a horizontal shift of the mentioned connecting rod (20).

As a result of this rotation, the organ (26) rotates around its fixed fulcrum (P1), which axis is perpendicular to the needle bar (4), inducing a swinging motion on the needle (28), the amplitude of which is a function of thew rotation angle of the lever (22). 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 a thread tightener (32) of a known type, so as to allow it to cross two thread braking devices (15) and (16) of a known type 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 needle (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 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 is a characteristic 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) is linked to a series of organs that actuate swinging shifts of the same, with variable amplitude, with a motion perfectly phased with the angular shifts of the needle (28), the swinging plane of said axle (3) being essentially parallel to said axis of fulcrum P1.

As consequence, said axle (3) is essentially parallel to said axis of fulcrum P1 in one of the positions that said axle (3) occupies during its swinging motions.

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) turns, 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 knots.

It should also be observed that the angular shifting of the axle (3) is made possible by an oscillating bearing (40) (refer to Fig. 6) which constitutes an oscillating fulcrum P5, having an axis essentially parallel to said first axle (4), on which the crochet axle (3) swings. 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 pre-set size upon them, a series of sequential knots (Figures 6, 8, 10, 11), on a material, in particular a filter bag, 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 in order to change the angular swinging size of the shaft (3) and to the needle bar (4). 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), in particular a knife, shown in Figure 9, where said device acts in combination with the other organs described above. In particular the knife comprises a lever (10) hinged to the frame of the machine, witch is provided with a cutting blade, at one end, and it is linked to an actuating kinematic motion (11 and 12) at the other end.

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 poini 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 firmly 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 numerous modifications, all of which are however falling within the scope of the innovative concept.

Claims

Device (1) for producing multiple sequential knots, of a simple or overlapped kind and different linear size, suitable for joining multiple layers of filter paper comprising:

a first axle (4), coinciding with a needle bar (4), carrying at an extremity (27) a sewing needle (28), where said needle bar (4) is free to slide in a support (26), that contains it;

a second axle (3), carrying at a first extremity a rotating crochet (29)

a third axle (2), on which a set of cams are assembled, essentially parallel to the said first axle (4) and perpendicular to said second axle (3);

support means for filter paper layers;

characterized in that :

said support (26) of the needle bar is apt to rotate around a first fixed fulcrum P1 to perform a swinging movement, around an axis that (i) is perpendicular to said first axle (4), (ii) is essentially parallel to the swinging plane of said second axle (3), carrying the crochet (29), and (iii) is essentially parallel to said second axle (3) in one of the position that said second axle (3) occupies during its swinging motions;

said second axle (3) has at a second extremity a second fixed flucrum P5, and is subjected to the action of means that drive angular movements of said second axle (3), with respect to the fulcrum P5, in phase with the movements of the needle bar (4),

said set of cam assembled on said third axle (2) are acting on a set of first, second and third lever means (22, 20,24,30;23,7), said first lever means (22,20) being apt to drive a fulcrum P3, located on the support (26), to drive the swinging movement of the support (26) around said fixed fulcrum P1, said second lever means (24,30) being apt to drive a fulcrum P2, located on the needle bar (4), to drive a sliding movement of the needle bar (4) inside the support (26), and said third lever means (23,7) being apt to drive a fulcrum P5 to drive a swinging movement of said second axle (3) around an axis essentially parallel to the first axle (4);

said support means (21) for filter paper layers being apt to clamp said layers during the shaping of the knot by said needle and crochet.
Device according to claim 1, characterized in that said swinging movement of the support (26) around said fulcrum P1, is driven by said first lever (22) through a connecting rod (20), said first lever (22) being driven by one or more cams mounted on said third axle (2).
Device according to claim 2, characterized in that said first lever (22) has his fulcrum in a point P4 the axis of said fulcrum being parallel to the axis of the fulcrum P1 and going through said point P4, said lever (22) being driven by said fulcrum P4, so that said needle bar (4) performs an angular displacement per every knotting cycle
Device according to claims 1 and 2 characterized in that the needle bar (4) is free sliding inside the support (26) in axial direction and said sliding is driven by second lever (24), through a connecting rod (30), said lever (24) being driven by one or more cams mounted on said third axle (2).
Device according to claim 1, characterized in that said second axle (3) is guided in its swinging movement by a slot (33), obtained in a fixed plain (9), through a bushing (8) sliding inside said slot (33).
Device according to claims 1 and 5, characterized in that the fulcrum P5, on which the second axle (3), carrying the crochet (29), swings during its angular displacements, is constituted by an oscillating bearing (40).
Device according to claim 5, characterized in that said bushing (8) is driven by the third lever (23), to slide inside the slot (33), through a connecting rod (7), said third lever (23) taking its motion for the angular shift from the fulcrum P4.
Device according to claim 7 characterized in that the swinging movements of the second axles (3) and the first axle (4) are synchronized, said swinging movement being driven by said first and third levers (22,23), actuated by one or more cams mounted on said second axle (2).
Device according to claim 8 characterized in that the amplitude of the angular movement of said second axles (3) and of said first axle (4) is a function of the shape of the the cams mounted on the third axle (2), for every knotting cycle.
Device according to the claim 9 characterized in that said swinging synchronized movements of the axles (2) and (3) cause sequential linear displacements of the needle (28) and of the crochet (29) (both in a sense and in the other and of different size) enabling said needle and said crochet to carry out said multiple sequential simple or overlapped knots having linear constant or variable size.
Device according to foregoing claims, characterized in that said device comprises thread braking devices (15) and (16), actuated by two cams reciprocally phased with the cam that drive the fulcrum P4, said cam being able to stretch and release, per every knotting cycle, linear sections of thread (14) of different size and at variable speed.
Device according to foregoing claims, characterized in that said device comprises a fixed hopper (21), containing a filter bag and comprising two planes substantially perpendicular to the first axle (4), said planes having an inner clearance such that said fixed hopper clamps with a light pressure the layers of filter paper to knot.
Device according to foregoing claims, characterized in that said device comprises a knife (10), actuated by the conjugate motion of a lever (12) and of a connecting rod (11), able to cut, in correspondence of the last knot of the series of sequential knots, a terminal section (37) of the thread (14), said terminal section (37) being inserted in an opening (38) of the last loop (36) of the knots made and remaining in this way clamped in said last loop (36) that remain closed and locked by following stretching.
A manufacturing machine for producing filter bags, characterized in that it comprises a device according to one of the foregoing claims.