US3400960A

US3400960A - Apparatus for knotting threads with the so-called weaver's knot

Info

Publication number: US3400960A
Application number: US589305A
Authority: US
Inventors: Daniele Messa
Original assignee: MES DAN ANNODATORI TESSILI DI PIETRO MESSA
Current assignee: MES DAN ANNODATORI TESSILI DI PIETRO MESSA
Priority date: 1965-10-28
Filing date: 1966-10-25
Publication date: 1968-09-10
Anticipated expiration: 1985-09-10
Also published as: DE1535891B1

Description

Sept. 10,1968 M. DANIELE 3,400,950

APPARATUS FOR KNOTTING THREADS WITH THE SO-CALLED WEAVERS KNOT Filed Oct. 25, 1966 8 Sheets-Sheet 1 M. DANIELE Sept. 10, 1968 APPARATUS FOR KNOTTING THREADS WITH THE SO-CALLED WEAVERS KNOT Filed Oct. 25, 1966 8 Sheets-Sheet P,

M. DANIELE Sept. 10, 1968 APPARATUS FOR KNOTTING THREADS WITH THE SO-CALLED WEAVER'S KNO'T 8 Sheets-Sheet 3 Filed Oct. 25, 1966 Sept. 10, 1968 M. DANIELE 3,400,950

APPARATUS FOR KNOTTING THREADS WITH THE SO-CALLED WEAVERS KNOT Filed on. 25. 1966 v s Sheets-Sheet 4 M. DANIELE Sept. 10, 1968 APPARATUS FOR KNOTTING THREADS WliTH THE SO-CALLED WEAVERS KNOT 8 Sheets-Sheet 5 Filed Oct. 25, 1966 P 10, 1968 M. DANIELE 3,400,960

APPARATUS FOR KNOTTING THREADS WITH THE SOCALLED WEAVERS KNOT Filed Oct. 25, 1966 8 Sheets-Sheet 6 M. DANIELE Sept. 10, 1968 APPARATUS FOR KNOTTING THREADS WITH THE SO'CALLED WEAVERS KNO'I 8 Sheets-Sheet 7 Filed Oct. 25, 1966 p 1968 M. DANIELE 3,400,960

APPARATUS FOR KNOTTING THREADS WITH THE SO-CALLED WEAVERS KNOT Filed Oct. 25, 1966 8 Sheets-Sheet 8 United States Patent Office 3,400,960 Patented Sept. 10, 1968 3,400,960 APPARATUS FOR KNOTTING THREADS WITH THE SO-CALLED WEAVERS KNOT Messa Daniele, Salo, Italy, assignor to Mes Dan Annodatori Tessili di Pietro Messa, Salo, Brescia, Italy, an

Italian firm Filed Oct. 25, 1966, Ser. No. 589,305 Claims priority, application Italy, Oct. 28, 1965, 6 8

22 Claims. (Cl. 289-3) ABSTRACT OF THE DISCLOSURE Apparatus for knotting threads with the socalled weavers knot are known. Said apparatus can be either manually or mechanically controlled and have a wide acceptance among Spinning mills and, in general, among all the industries employing threads at large.

All the known devices essentially consist of a rotary hook equipped with scissors and a pincer for cutting and holding a thread end, a device for overlapping the threads to be knotted at the sides of the device and a device for withdrawing and cutting the end of the second thread.

To knot two threads, these are passed transversally through two grooves in the two sidewalls of the device, whereafter a trigger is pulled with a finger if a manually actuated knotter is in the question, otherwise by meansof a control member if an automatic knotter is used, so as to actuate the several members and, upon having allowed the trigger to be returned to its home position, the knotted threads are withdrawn from the device.

Conventional devices of the kind referred to now are unsatisfactory under many respects and are affected by several shortcomings, limitations and drawbacks, mainly when threads formed by man-made or synthetic fibres, or mixtures thereof with natural fibres, are to be knotted. Said conventional device do not ensure a high degree of reliability in the formation of the knots, knot-tying necessitates a certain time and thus a quick-acting operation in a friction of a second is not possible so that no evenness of the knots can be achieved. Another defect lies in that the conventional devices cannot generally be adapted to a wide range of count of yarn for the threads to be knotted, said apparatus being generally individually prepared for threads of a certain narrow count range.

An object of the present invention is thus, mainly, to do away with the drawbacks and limitations of the conventional knotters so as to provide an apparatus which is of easy construction, simple upkeep and long-lasting, adapted to be used in dustand humidity-polluted spaces and capable of tying knots in very short times with full reliability in operation under the unfavourable conditions enumerated above and with a high accuracy in the size of knots whenever regular size threads are used, and capable of ensuring a perfect tying of the knots so as to permit tying a number of different kinds of threads and yarns over a wide range of counts. By so doing, the present invention aims to providing a knotter suitable for the up-to-date production techniques both in the field of the usual knot-formation by hand in that of automatic knot-formation.

These and other objects are achieved with the subject inventive device which is essentially characterized in that it is equipped with cammed means for controlling the thread-overlapping and thread-deflecting devices, the cam outlines being such as to restore to their home positions said thread-overlapping devices and said thread-deflecting devices at the end of the forward stroke of the actuating means; in that it has a pivotal extractor guided in such a way as to go away of the rotary hook during the thread-withdrawal movement and in that it is equipped with adjusting means for the attune-ment of the movements of the several component mechanisms and for the adaption to several kinds and counts of the threads to be knotted.

In order that the several features of the inventive knotter may be more fully understood along with the advantages attendant thereto, an exemplary and non-limiting embodiment thereof will be described in the following, the disclosure being aided by the accompanying drawings, wherein:

FIGURES 1 and 2 are perspective top views of a device according to the invention, having a sidewall cut away, said views showing the device in idle position and in the position at the end of the forward stroke of the actuating trigger with the fully extended extractor, respectively.

FIGURE 3 is a plan view of said device.

FIGURE 4 is a diagrammatical cross-sectional view taken along line IV-IV of FIG. 3 and in which the members directly supported by the sidewall of the device have been omitted.

FIGURES 5 and 6 are cross-sectional views taken along lines V-V and VI-VI of FIG. 4, respectively.

FIGURES 7 and 8 are cross-sectional views taken along lines VII-VII and VIIIVIII of FIG. 5., respectively.

FIGURE 7a is illustrative of a modification of a component part shown in FIG. 7.

FIGURES 9 and 10 are views from inside and in plan of a modification of the component parts supported by the sidewall shown in FIG. 8.

FIGURES l1 and 12 are two views, shifted degrees apart from one another, of an embodiment of the rotary hook.

FIGURES l3 and 14, likewise, are two views, shifted 90 degrees apart from one another, of another embodiment of the rotary hook.

FIGURES l5 and 16 are illustrative, in side elevational and cross-sectional view taken along the line XVIXVI of FIG. 15, respectively, of a constructional detail, and

FIGURES l7 and 18 show the tying of two threads with the weavers knot, in the form of .a loose and a tight knot, respectively.

The subject device comprises two shaped flanks, l and 2, respectively, connected by two spreading

stirrups

3 and 4, respectively.

The sidewall 1 has, centrally and in its upper portion, an opening which is partially masked by a tag 5 affixed to the sidewall itself so as to form two

grooves

6 and 7 adapted to receive the two ends to be knotted, the groove 6 having in its lower portion a small perpendicularly running slit 6a. Also the sidewall 2 has two

grooves

8 and 9, respectively, separated by a finger 10 formed by the sidewall 2 itself (see FIG. 8). Laterally of said grooves, the sidewalls have a suitably sloping outline which converges to facilitate the insertion of the ends to be knotted into the respective grooves.

The side wall 2 solidly carries a bracket 11 to which a crank (not shown) can be affixed if the device is to be 3 manually actuated, said bracket being adapted to the use as a mounting bracket if the device is to be mounted on a machine.

On a pivot 12, transversely affixed to the two

sidewalls

1 and 2 is pivotally mounted by a bushing 16, a body 13 to which a lever 14, acting as a trigger, is fastened said body carrying control cams to be described later.

A coil spring 15 wraps the bushing 16 and rests with one end onto the rotatable body 13 and, with the other end, on the bracket 11 so as to maintain the body 13 in its home position as shown FIG. 4.

The body 13 rotatably supports also a cylindrical dowel 13 which is adapted to rotate about its own axis by means of a roller bearing 17 capable of cooperating with a helical member 19 idly and rotatably journalled between the two

stirrups

3 and 4. As seen more detailedly in FIGURES 3 and 4, the member 19 has two

helical ridges

19a and 1%, respectively, with which the dowel 18 alternately cooperates when the body 13 is rotated in clockwise and anticlockwise direction respectively, as viewed in FIG. 4. The ridge 19a has a variable pitch, that is, the radius of the helix is increased in the right-hand portion of member 19 (as viewed FIG. 4), whereas the ridge 1% has a virtually constant pitch. The diameter of the dowel 18 is the same as the diameter of the milling cutter with which member 19 has been shaped.

Member 19 solidly carries a gear 20 meshing with a second gear 21 rotatably supported by a pivot 22 and being an integral part of a rotary hook, generally indicated at 23.

Said hook, which is detailedly shown in FIGS. 11 and 12. comprises scissors having a fixed blade 24 and a movable blade 25 and a pincer formed by a fixed member 26 and by the same movable blade 25 which is adapted to rotate about a pivot 27 and has two

tail portions

28 and 29 in its rear part. During the rotation of the hook 23 about the axis of the pivot 22, the two

tails

28 and 29 of the movable blade 25, cooperate with the inner profile of an annular cam 30 afiixed by two

studs

31 and 32 to the stirrup 3 so as to wrap the rotary hook 23. Closing and opening of the scissors and pincer is thus controlled.

Instead of a three-membered hook 23 as shown FIGS. 11 and 12, it is possible to mount on the device a pluralmembered hook, such as a five-membered hook as shown FIGS. 13 and 14. Said hook, generally indicated at 23a comprises, similarly to the one described just now, scissors formed by a fixed blade 24a and a movable blade 25a along with a pincer which, in the case in point, comprises two fixed

members

26a and 26b, the movable blade 25a and another movable member 25b fastened to the movable blade by means of a pin 250.

The movable blade 25a and the movable blade 25b can be rotated about a pivot 27a, to be inserted between the fixed blade 24a and the first fixed member 26a, and be tween the latter and the second fixed member 2611, respectively, as clearly shown FIG. 14. The movable blade 25:: exhibits, also in this case, two

tail portions

28a and 29a capable of cooperating with the innermost profile of the cam 30 for closing and opening the scissor and the pincer. This second type of rotary hook is particularly suited to very slippery threads inasmuch as it ensures an improved and more reliable grip and hold of the thread end cut by the scissors mounted on said hook.

The sidewall 1 of the device has on its inner face (see FIG. 7), a couple of overlapping

members

33 and 34 which have the task of overlapping, on a side of the device, the two threads to be knotted, holding them during the formation of the knot and setting them free after knotting with the weavers knot. Member 33 has a main slot 35 and a secondary slot 36 and, likewise, member 34 has a main slot 37 and a secondary slot 38. The two

members

33 and 34 are interlinked by a pin 39 and can be moved with respect to one another on two parallel planes, member 33 being pivotally attached to the sidewall v a pin 40. To the free end of member .34 a lever 41 is pivoted at 42 to the sidewall 1 and has at the end of its second, shorter limb, a small pin 43 which enters a cammed slot 44 formed in a plate 45 afiixed to the rotary body 13. The outline of the slot 44 is very much the same as an L as clearly shown in FIG. 7, wherein the overlapping

members

33 and 34 are shown in their at rest position. Starting from this position and rotating the body 13 with the plate 45 clockwise about the axis of the pin 12 by acting on the trigger lever 14 (see also FIG. 4), the pin 43 must adhere to the outline of the slot 44 causing the lever 41 to be rotated about its pivot 42. Until the pivot 43 is in the first section of the slot 44, the results are a rotation of the member 33 anticlockwise about the pivot 40 and a clockwise rotation of member 34 about the pivot 39, with a simultaneous translation of the latter member towards the rights as viewed FIG. 7. As the pivot 43 reaches the second section of the slot 44, a reversal of the movement is experienced, that is, the lever 41 is rotated anticlockwise about the pivot 40, member 34 is displaced towards the left and rotated anticlockwise, and member 34 is rotated clockwise about the pivot 40. Thus, at the end of the rotation of body 13 clockwise about the axis of the pivot 12 (a rotation whose amplitude is of about degrees), the overlapping

members

33 and 34 are restored to their home position as shown FIG. 7, but the pivot 43 is now at the opposite end of the slot 44.

During the return stroke of the body 13 and of the plate 45, the above described movements of the overlapping members are reversed.

To the sidewall 1 is affixed, moreover, a leaf spring 46, cooperating with member 34 so as to hold the thread while the knot is being tightened.

FIGURE 7a is illustrative of a modification of the overlapping meber 34 shown FIG. 7. Said modified member indicated at 34a, has its secondary slot 38a shifted towards the slot 37 as compared with the slot 38 of member 34 shown FIG. 7. In FIG. 7a, the slot 38 is shown in phantom and the shifting of the slot 38a is indicated as x. The result is that, if a single thread only is inserted in the

slots

7 and 8 of the device, said thread is surely grasped by the rotary hook 23 and cut by the scissors 24- 25 thereof, as contrasted with that which occurs in the conventional devices. This fact is of a particular significance when the device is applied to automatic spoolers.

Member akin to the overlapping

member

33 and 34 are catered for also on the inner face of the sidewall 2 (see FIG. 8). More particularly, there are two deflecting

members

47 and 48 fulcrumed to the sidewall 2 by

pivots

49 and 50, respectively, having, each, a

slot

51 and 52, respectively. These last named members fulfil the function of deflecting the two threads to be knotted from the side of the sidewall 2 of the device, said threads being passed through the slots 8 and 9', respectively, of said sidewall. Member 47 has a humped portion 53 and the upper portion of member 48 is elevated with respect to the lower portion so that, in the mutual rotation of the two

members

47 and 48 about their

respective pivots

49 and 50, the upper end of member 48 may overlie member 47 in correspondence with the humped portion 53 thereof. Each

member

47 and 48 has, then, :an arm- 54 (and 55, respectively), the former having a slot 56 which enga es a pin 57 sold with the arm 55 of member 48.

The movements of the two

members

47 and 48 are thus mutually attuned so that, as either is rotated through a certain angle, clockwise, about its own pivot, the other one is rotated counterclockwise about its own pivot, and vice versa, it being enough to actuate either member for bringing about said rotations. As a matter of fact, the arm 54 of member 47 carries a pivot 58 which engages a cammed slot 59 formed in a plate 60 afiixed to the rotary body 13 on the face away of the plate 45. The outline of said slot 59 has a substantially circular central portion, the arc of circle being centered about the centre of rotation of the plate 60 (axis of the pivot 12), and

sloping terminal portions, which are approximately radially oriented with respect to said center. The position shown FIG. 8 is the home position. By rotating the body 13 with the plate 60 counterclockwise, starting from said home position, the pivot 58 is firstly rotated clockwise about the pivot 49 and therewith member 47 is also rotated, whereas the other member, 48, by virtue of the connection slot 56pivot 57 is simultaneously caused to be rotated counterclockwise about the pivot 50. As the pivot 58 reaches the central portion of the slot 59,

members

47 and 48 virtually remain in the rotated position whereafter, with the further rotation of the plate 60 with the pivot 58 in the second terminal portion of the slot 59,

members

47 and 48 are reported very much to their home position. All these closing and re-opening movements of the deflecting

members

47 and 48 take place during the advance stroke of about 90 degrees of the body 13 with the plate 60. During the return stroke, these movements are reversed.

A modification of the control mechanism for the deflecting members is shown in FIGS. 9 and 10, showing the sidewall 2 with the

members

47 and 48 respectively fulcrumed at 49 and 50 and connected to one another by means of the pin 57 and the slot 56, respectively provided for on the arm 55 of member 48 and on arm 54 of member 47. i

In this case, the arm 55 of member 48 carries a pivot 58a, engaging a cammed slot 59a, provided for in a plate 60a, this latter being afiixed to the rotatable body 13. To the latter plate a second shaped plate 61 is affixed, whose shaped edge 62 is adapted to come into contact with a pivot 63 afiixed to the member 47. The mutual positioning of the

plates

60a and 61 is an adjustable one: as a matter of fact, the screw 64 looking the two plates, is

passed through a slot 65 formed in the plate 61, this latter being enabled to etfecta limited rotation with respect to the plate 60a, about the pivot 12.

Starting from the home position as shown FIG. 9 and by rotating the body 13 counterclockwise with the

plates

60a and 61 about the pivot 12, the slot 59a of the plate 60a effects an initial rotation, clockwise, of the pivot 58a and member 47 about the pivot 49 along with a simultaneous anticlockwise rotation of member 48 about the pivot 50.

As the pivot 58a reaches the central circular portion of the slot 59a, the deflecting members-47 and 48 are in the closure position, whereat they remain until the shaped edge 62 ofthe plate 61 abuts the pivot 63 ofmember 47, thus causing the two members to be openedagain. By adjusting the position of the plate 61 relative to the plate 60a it is possible to adjust the opening of the defiecting members at the end of the forward stroke of the rotatable body 13 as well as the instant of time at which the opening movement of said deflecting members is taken up again. During the return stroke of the body 13, the above enumerated movements are reversed.

Still another significant member of the device is the extractor, generally indicated at 66 (see FIGS. 1 to 4 and 6 to 7), whose task is to grasp either thread after the formation of the knot and removing said thread so as to tighten and close the knot. Said extractor substantially comprises a twice-curled member 67 having at either end, a hooklike projection 68, and solid, at the other end, to a bushing 69 parallel to the central portion of member 67. Bushing 69 is freely rotatably mounted about a transversal pivot 70 afiixed to both

sidewalls

1 and 2. To the part of the member 67 near the bushing 69 is linked, by means of a pin 71, a rod 72 (see FIG. 7) which is linked, in turn, at its other end and by means of a pin 73, to the end of a lever 74 pivoted at 75 to the sidewall 1 of the device. Said lever 74 has, roughly midway, a pin 76 engaging a shaped slot 77 provided for in the plate 45 affixed to the rotatable body 13. r

The slot 77 has a first portion (on the right, as viewed FIG. 7) having a substantially circular outline whose center is the axis of rotation of the plate 45, a second portion having an outline with a radius which is gradually increased with respect to said axis and a third portion having a substantially circular outline centered at the axis of rotation of the plate 45 and with a radius greater than that of said first circular portion. Thus, by rotating the body 13 with the plate 45 clockwise about the axis of pivot 12 (as viewed FIG. 7) starting from the illustrated home position, the result is that, firstly, the control lever 74 of the extractor 66 remains at standstill, to be then entrained to rotation anticlockwise about its own pivot 75 thus causing, through the rod 72, a rotation of the extractor 66 clockwise about the axis of the pivot 70, to remain at standstill again as the pivot 76 is in the third section of the shaped slot 77. It should also be noticed (see FIG. 4) that during progress of said rotary movement, the hook 68 of the extractor 66 goes through an arc of circle centered at the axis of the pivot and approaches first the rotary hook 23, then positively going far therefrom to come out completely of the space confined by the

sidewalls

1 and 2 of the device (see the position taken by the extractor at the end of the removal stroke as shown FIG. 2).

In order that an adjustment of said removal movement is possible along with a variation of the operability of the extractor with respect to the rotation of the rotary hook 23 suitably to attune both movements and to obtain the most favourable removal conditions also as a function of the different counts of yarn, the pivot of the control lever 74 of the extractor 66 is adjustable. This detail is clearly shown in FIGS. 15 and 16. As viewed in these figures, the pivot 75 is simultaneously afiixed to a circular disk 78 inserted in a corresponding hole 79 formed in the face of the sidewall 1. Said disk 78 is integral with a member 80 applied to the outer face of the sidewall 1 and having a circular slot 81 whose center is the same as that of the circular disk 78. A screw 82 screwed onto the sidewall 1, passes through said slot 81 and holds said member 80 with its head. It is obvious that, by loosening the screw 82 and rotating the member 80 within the range allowed by the slot 81, the pivot 75 can be shifted and the intervention of the extractor 66 relative to the rotation of the hook 23 can correspondingly be advanced or delayed.

A similar adjustability, obtained with means identical .to those described in connection with FIGS. 15 and 16,

is provided for the

pivots

42 and 49 appertaining to the control lever 41 for the overlapping

members

33 and 34 and for the deflecting member 47, respectively. Said adjustments are not shown in the drawings in detail and are intended both for adjusting the attunement of the overlapping and deflecting devices of the threads by varying the instant of time at which said devices enter into action, and for backlash takeup purposes.

The extractor 66 carries a second pair of scissors, indicated generally at 83 (see FIGS. 2, 4 and 6) which is intended to cut the second thread. More precisely, on the central portion of member 67 of the extractor is affixed, by a screw 84, a slider 85 solid with a supporting member 86, the screw 84 being passed through a slot 87 of member 67 and being screwed into the slider 8-5 so as to displace and adjust same along the central portion of member 67 parallely of the axis of rotation of the extractor 66.

The supporting member 86 carries a pin 88 to which two

blades

89 and 90 are fulcrumed: blade '89 is movable and blade 90 is afiixed to the supporting member 86 but adjustable with respect thereto. In fact, said blade 90 has an extension 91 (see FIG. 4) with a slot 92, through which a set screw 93 is passed.

It is thus possible limitedly to rotate the blade 90 about the pivot 88. The movable blade 89 has an extension 94 with slot 95 wherein a pivot 96 is engaged, solid with a curved lever 97 pivoted at 98 to a portion 99 of the stirrup 4. This connection is such that, when the extractor 66 is in its home position (as viewed in FIG. 4), the scissors 83 are open While, during the removal movement, the scissors 83 close to cut the end of the second thread. The movement in which the scissors 83 effects this cut during removal can be varied by suitably adjusting the position of the fixed blade 90 on the supporting member 86 to ensure that the thread is cut when the knot is well tightened and cannot shrink any more. By so doing a constant evenness of the knots is achieved.

The adjustment of the position of the scissors 83 of the extractor 66 by displacing the slider 85 on member 67 permits to approach said scissors, to a greater or lesser extent, to the axis of the rotary hook 23. Said adjustment, combined with the easy removability of said rotary hook, is intended for adapting the device, in an extremely simple way, to a wide range of kinds of threads and counts of yarn, and for suitably varying the length of the ends of thread cut by the two scissors thus ensuring a very satisfactory tightening of the formed kont.

The adjustment of the

pivot

42 and 49 of the threadoverlapping and deflecting devices affords a control of the most suitable position of the threads with respect to the rotary hook, along with a full reliability of the device.

The extractor 66 moving along an arc of circle which goes far from the rotary hook, gives rise to a perfect tightness of the knot and makes it possible to adjust and vary the instant of time at which said extractor enter action with respect to the rotation of the hook, that which affords the attunement of the several movement under any conditions.

By adjusting the opening of the deflecting devices at the end of the stroke the drag applied on removal can be adjusted, all this without exceedingly pulling the knot both in the case of thin and sensitive threads which requires a short removal arc, and in the case of thick and slippery threads requiring a longer removal stroke.

In summation, with the inventive device, on account of the several adjustments and the particular design features, a continuous control is effected of the formation and tightening of the knot, the result being a great reliability in operation enabling the knot-formation speed to be increased.

It should be noticed, in this particular connection, that at the end of the forward stroke of the trigger, the knotted threads are free on both sides of the device and can be withdrawn, inasmuch as they are no longer held by the overlapping and deflecting devices. As a matter of fact, these devices return to their home positions as the body 13 and the trigger 14 reach the ends of their forward strokes, so that it is no longer necessary, for the knotted threads to be removed, to wait the return of the body 13 and trigger 14 to their home positions. This result, which has been obtained according to the invention on account of the particular configuration of the control cams for the overlapping and deflecting devices, not only aflords the paramount advantage of considerable time savings over the conventional devices, but is also such as to involve a more reliable operability, inasmuch as the knotted thread cannot be entangled with the rotary hook or the extractor during their return movements, nor can it inadvertently cut: this drawback was very often experienced with the conventional devices in which the overlapping and deflecting devices stood closed at the end of the triggers forward stroke. The inventive device is thus enabled to tighten the knot in a very short length of time, a fraction of a second, thus affording a full reliability and lending itself more particularly also to its being used in the field of automatic knot-formation, besides that of the manual knot-formation techniques.

It is to be noticed also that a contribution towards said result is also afforded by the particular configuration of the driving mechanism, especially the helical member 19. In fact, the varying outline of said member, 19a fulfils the requirement of achieving, with a minimum force when the forward stroke of the trigger 14 is started, an increased angular speed of the rotary hook, along with an increased force at the end of said stroke, during the cutting step.

The driving pin of the member 19, for its being supported by a rolling bearing, converts the sliding friction into rolling friction, the force necessary to actuate the device being consequently diminished.

All the mechanisms and component parts of the inventive device have been designed so as to require a minimum upkeep, virtually no lubrication, so as to ensure a long life even under unfavourable working conditions in dustladen and moist environments.

Merely by way of example, FIGURES 17 and 18 are illustrative of a so-called weavers knot, to be formed with the inventive device. Such a knot is conventionally known and, as outlined at the outset, devices for its f rmation are already known. It is thus deemed redundant to set out in detail the operation and the several knotforming steps.

FIGURE 17 shows the loosened knot, whereas FIG- URE 18 is illustrative of the finished tightened knot.

What is claimed is:

1. A device for knotting threads with the so-called weavers knot comprising, between two sidewalls each of which has two slots for introducing the threads to be knotted, a rotary hook with scissors and a pincer for cutting and holding a thread end, mechanisms for overlapping and deflecting the threads to be knotted in correspondence with the sides of the device, a removal device for cutting the end of the second threads, and means for actuating the several members and mechanisms, characterized in comprising cammed means for controlling the overlapping and deflecting mechanisms, said means having such an outline as to restore to their home positions said overlapping and deflecting devices on completion of the forward stroke of said actuating means, an extractor fulcrumed and guided so as to be driven away of the rotary hook during the removal movement and adjustment means for the attunement of the movements of the several mechanisms and members to adapt them to different kinds and counts of yarn of the threads to be knotted.

2. A knot-forming device according to claim 1, characterized in that said actuating means comprise a body which is rotatably mounted about a pivot carried transversally of the two side-walls and having laterally plates in which shaped slots have been formed to engage pins connected to the driving mechanisms for driving the overlapping and deflecting devices and the extractor, said body being biased by a spring which maintains it in its homeposition, means being provided to rotate said body through a predetermined angular stroke against the bias of said spring.

3. A knot-forming device according to claim 2, characterized in that said rotatable body has on one side a plate with a substantially L shaped slot engaging a pivot carried by a lever fulcrumed at a point midway of the relative side of the device and linked at its other end to an overlapping device equipped with slots for grasping either of the threads to be knotted, said member being linked at its opposite end to 'a second overlapping device fulcrumed midway of said sidewall of the device and having also slots for seizing the second thread to be knotted, in the home position of the rotatable body the two overlapping devices being arranged with their slots facing each other laterally of the two slots in the respective sidewall and, at the end of the forward stroke of said rotatable body, they return substantially to said home position.

4. A knot-forming device according to claim 3, characterized in that the pivotal point of said lever is adjustable.

5. A knot-forming device according to claim 3, characterized in that a second shaped slot is formed in said plate for controlling said extractor.

6. A' knot-forming device according to claim 1, characterized in that said extractor is rotatable about a pivot transversally atfixed to the two sidewalls away of the rotary hook with respect to the middle plane containing the axis of rotation of said rotatable body, to the extractor a rod being linked which, in turn, is linked to a lever fulcrumed at either end to 'a sidewall of the device and carrying in an intermediate point a pivot engaging said second shaped slot of the plate afiixed to said rotatable body.

7. A knot-forming device according to claim 5, characterized in that said second slot has an outline such that the first section thereof has a radius which is substantially constant with respect to the center of rotation of said rotatable body, the second section of said slot has a gradually increasing radius and the third section has a constant radius again, longer than the radius of said first section.

8. A knot-forming device according to claim 6, characterized in that the position of the pivotal point of the extractor control lever is adjustable.

9. A knot-forming device according to claim 2, characterized in that said rotatable body has, on its other side, a second plate with a shaped slot whose outline has a central section with a radius constant with respect to the center of rotation of the body, two terminal sections being substantially radial and going far from said center, to the sidewall of the device confronting said second plate two deflecting members being pivoted, each having a slot for grasping the threads to be knotted, said two members being hingedly connected to one another so as to be compelled to rotate in opposite directions about their pivotal points, at least one of said members carrying a pivot to engage the shaped slot of said second plate, the two deflecting members being arranged, in the home position of said rotatable body, with their slots in trout of each other and laterally of the two slots of the respective sidewall, said members substantially returning to their home position on completion of the forward stroke of said rotatable body.

10. A knot-forming device according to claim 9, characterized in that the pivotal point of either deflecting member is adjustable.

11. A knot-forming device according to claim 9, characterized in that, to the second plate carrying the shaped slot for controlling the movement of the deflecting members a third plate is superimposed having a shaped outline intended to be contacts by a pivot solid with either deflecting member at the end of the forward stroke of said rotatable body.

12. A knot-forming device according to claim 11, characterized in that said third plate is adjustable relative to said second plate.

13. A knot-forming device according to claim 4, characterized in that each of said pivots is affixed to an eccentrical point of a circular disk inserted into a hole of the sidewall of the device and capable of being locked in several angular positions.

14. A knot-forming device according to claim 1, characterized in that said rotatable body carries a pin cooperating with a helically shaped member freely rotatably supported about an axis perpendicular to the axis of rotation of said rotatable body between the two sidewalls oi the device, said member having a variable-radius helical outline, and precisely at small radius outline in the portion where said pin cooperates therewith 'at the beginning of the forward stroke of said rotatable body, and an increasing-radius outline in the final portion wherein said pin cooperates with said helical member towards the end of the forward stroke of said rotatable body, means being provided for transferring a rotary drive from said member to said rotary hook.

15. A knot-forming device according to claim 14, characterized in that said member has a. second, constantradius, helical outline with which said pin cooperates during the return stroke of said rotatable body.

16. A knot-forming device according to claim 14, characterized in that said pin is circular and is supported within said rotatable body by means of a rolling bearing.

17. A knot-forming device according to claim 1, characterized in that the extractor comprises a twice bent member with a central portion parallel to the axis of rotation of said extractor, said central portion carrying scissors which can be adjusted in the longitudinal direction of said central portion.

18. A knot-forming device according to claim 17, characterized in that said scissors are mounted on a supporting member which is displaceable by means of a slider on the central portion of said extractor, said central portion being fitted with a slot through which a slider-locking screw is cause to pass.

19. A knot-forming device according to claim 18, characterized in that said supporting member carries a fixed blade and a movable blade, the latter being rotatable about a pivot solid with said supporting member and having a slot engaging a pivot solid with a lever fulcrumed at a fixed point of the device.

20. A knot-forming device according to claim 19, char acterized in that said fixed blade is adjustably mounted on said supporting member and can be locked thereto.

21. A knot-forming device according to claim 1, characterized in that said rotary hook is surrounded by 'an annular cam face with which two tail portions mounted on the rear of the movable blade of the hooks scissors cooperate during the rotation of said hook.

22. A knot-forming device according to claim 21, characterized in that said movable blade is connected to a second movable member, said hook also comprising, in addition to said fixed blade, also two fixed spaced apart members which form, together with said movable members, a multiple pincer.

References Cited UNITED STATES PATENTS 2,287,311 6/ 1942 Hulfstickler 289-3 2,821,421 1/1958 Smith 289-3 3,217,211 1/1962 Trost 289-3 LOUIS K. RIMRODT, Primary Examiner.