US2300051A

US2300051A - Method of and mechanism for tying knots

Info

Publication number: US2300051A
Application number: US277755A
Authority: US
Inventors: Harry G Lind
Original assignee: Barber Colman Co
Current assignee: Barber Colman Co
Priority date: 1939-06-07
Filing date: 1939-06-07
Publication date: 1942-10-27
Anticipated expiration: 1959-10-27

Description

Oct; 27, 1942. H. cs. LlND METHOD OF AND MECHANISMS FOR TYING KNOTS Filed June 7, 1939 4 Sheets-Sheet l INVENTOR Harry Lind Oct. 27, 1942. H. s. LIND METHOD OF AND MECHANISMS FOR TYING KNOTS Filed June '7, 1959 4,Sheets-Sheet 2 |NVENTOR 7 Ha rry G. L (Ln 0? BY m m J r ATTORNEYS Oct. 27, 1942. H. e. LlND 2,300,051

METHOD OF AND MECHANISMS FOR TYING KNOTS I Filed June '7, 1939 4 Sheets-Sheet 5 INVENTOR Harry G L ind ATTORNEY 5 Oct. 27, 1942. H. G. LIND METHOD OF AND MECHANISMS FOR TYING KNOTS Filed June '7, 1939 4 Sheets-Sheet 4 m 0 aw G. Lind ATTORNEYS INVENTOR TE toNE E M FWQK @Nkk Elk Patented Oct. 27, 1942 Harry G. Lind, Rockford, 111., assignmto Barber- Colman Company, Rockford, 111., a corporation of Illinois Ap flication June 7, 1939, Serial No. 277,755

20 Claims.

The invention relates to an improved method of and apparatus for tying knots, and more particularly, for uniting threads or strands of such material as woolen yarn.

in some aspects the present invention may be considered as an improvement upon the knot-tying method and apparatus disclosed in Burt A. Peterson Patent No. 1,657,407 issued January 24, 1928 in which a pairof threads are united by a so-called weavers knot.

A weavers knot has been found to be well adapted to the permanent uniting of the ends of cotton threads or yarn. In the case ofwool, however, a weavers knot is likely to become untied, and it is therefore the general object of the present invention to provide a method of and mechanism for tying knots which, while not limited to use with woolen yarns, is capable of firmly and permanently uniting yarns of such material.

More specifically, it is an object of the invention to provide a method of and mechanism for tying together a pair of threads by means of a novel form of knot, which is somewhat related in form to a weavers knot, but which embodies variations in the configuration and relative positions of the threads such that the threads are firmly interlocked and held together even though made of such materials as wool.

Further objects and advantages of the invention will become apparent as the following description proceeds, taken in connection with the accompanying drawings in which:

Figure 1 shows a completed knot of novel form made in accordance with the improved method of knot tying herein disclosed.

Fig. 1 shows the loop formation of the threads before the knot of Fig. l is drawn tight and completed.

Fig. 1 shows the configuration of the threads intermediate the steps of Figs. 1 and 1, respectively. i

Fig. 2 is a side elevation of a knotter mechanism embodying the invention. Parts moving to the right in this view are hereinafter referred to as moving outward1y."

'Figs. 3 and 4 are, respectively, enlarged detail end and plan views (partly in section along the lines 33 and 4l, respectively, in Figs. 2 and 3) of the mechanismjor actuating the knotter post.

Fig. 5 is an enlarged detail bottom plan view of one of the thread clamps of the knotter mechanism.

Figs. 5, 5 and .5 are stop motion views similar to Fig. 5 showing successive steps in the operatio of the parts illustrated. I

Fig. 6 is a fragmentary detail view of part of the mechanism of Fig. 5.

Fig. 7 is an enlarged detail perspective view of the slack take-up mechanism included in the knotter.

Figs. 8 to 12, inclusive, are fragmentary perspective views of the knotter mechanism showin successive steps'in the knot tying operation.

Fig. 13 is a time chart illustrating the sequence of operations of the various mechanisms by the controlling cam.

Referring more particularly to the drawings, Fig. 1 shows a completed knot uniting a pair of threads at and b. For purposes of exemplifica-' tion only, it will be assumed that thread a is a reserve thread leading from a bobbin in a windin machine and that thread b is an exhausted thread on a cheese or yarn mass which is being wound in the machine. To make more readily discernible the convolutions of the two threads a and b, these threads have been shown in the drawings as white and black, respectively. The knot of Fig. 1 is of novel form and has been found capable of firmly and permanently uniting woolen threads. It is referred to herein as a doubly interlocked knot.

To better understand the configuration of the threads a and b in the doubly interlocked knot of Fig. 1, reference should be made to Fig. 1 In this figure the threads are shown before they are finally drawn tight to complete the knot. In Fig. 1, the threads 11 and b are looped in what, for purposes of explanation and analysis, may conveniently be termed a modification of a loose weavers knot. A weavers knot as such is, of course, a well recognized standard knot, and as to it, reference may be made, for example, to Fig. 29 of said Peterson patent referred to above.

Upon a comparison of a weavers knot with that of Fig. 1 herein it will be seen that the two are alike in that, first, there are oppositely extending loops or and D1 in the end portions of the respective threads 0 and b, second, the standing part oz, of one thread 0, extends through the loop in in the other thread b, and third, the standing part b2 and end b: of the other thread b extend side by side through the loop at in the first thread a. The knot of Fig. l diifersfrom a standard weavers knot, however, in that the end a: of the first thread a is'not clamped between the standing part of the thread a and the oposed portions of the standing part be and end be of the other thread b, but is, on the other hand, twisted about the standing part as of the thread a and thrust outwardly from the remainder of the stands. By virtue of this difierence in configuration of the strands it is possible finally to draw the knot tight in a manner which will hereinafter appear, so as to form the strong and durable doubly interlocked knot of Fig. 1.

In accordance with one aspect of the present invention the threads to be united are preliminarily looped in a somewhat loose form with the strands arranged as shown in Fig. 1 in what is termed herein a modified form of Weaver's knot. Then, to complete the novel knot of Fig. 1, the twisted portion of one of the threads (shown in Fig. 1 at in) is pulled through the loop of the other thread (shown as bi) as an incident to drawing the knot tight (Fig. 1 In this wayv the loop bl, in the thread b, encircles and firmly clamps the twisted portion 04, of the thread .a, against the standing part a: of the thread a. In general, the strands are so interwoven or interlocked that an extremely strong and firm knot is formed even though the strands or threads be made of wool.

In carrying out the present invention the preliminary looping of the therads in the form of a modified Weaver's knot such, for example, as that shown in Fig. 1, is preferably accomplished by means of a novel method of knot tying herein disclosed. Generally stated, this method comprises (see' Figs. 8 to 12), seizing a bight in one of the threads (such as the thread a) to form a main loop. The loop is then made into what may be termed a "doubly twisted loop by twisting the thread at the base of the loop about itself through substantially a turn and a. half at the base of the loop (see Fig. 8). Then a bight of the same thread, adjacent the main loop is drawn through the loop to form a temporary second loop. Thereupon a second thread (such as the thread b) is inserted through the second loop thus formed, and the second loop subsequently withdrawn from the main loop, together with the inserted thread, thereby forming a third loop encircling one of the standing parts of the thread having the main loop in it. In the course of this withdrawal operation the second or temporary loop is dissolved. By manipulatin the threads in this manner the formation of the initial main loop forms, for example, the final loop cu in the thread a and leaves this thread twisted at the base of the loop as shown at or. similarly, the third loop, so-called above, 'is represented in Fig. 1 by the loop b in the second thread b. Having thus preliminarily arranged the threads as shown in Fig. 1, they may then be pulled tight into the form of Fig. 1 and then Fig. 1, as previously described The novel knotter mechanism herein disclosed, for carrying out the knotting method outlined above, is basically similar to that disclosed in said Peterson patent. Accordingly, reference may be had to such patent for a general description of the apparatus and for details of parts which are substantially identical. The more detailed portions of the description herein are directed primarily to the difierences in construction which make possible the use of the knotter herein disclosed for tying the novel form of doubly interlocked knot of Fig. 1, as distinguished from an ordinary weavers knot such as is tied by the knotter of said Peterson patent.

Referring now to Fig. 2, the present embodiment of the knotter mechanism is adapted to receive a pair of threads (not shown in Fig. 2) at its outer end for tying them together. For example, one of the threads may be a reserve thread, that is, one from a reserve bobbin, and the other an exhausted thread end from a cheese or yarn mass in a winding machine. For an example of a winding machine of the type referred to, Howard D, Colman Patent No. 1,267,977 may be considered. 0f the two threads noted, the reserve thread is operated upon first in the present mechanism and, consequently, the manipulations of this thread will be first described.

The reserve thread is seized at two vertically spaced points, to form a bight between them, by the suction nozzle 9 and a lower clamp ll (Fig. '2), the loose end of this reserve thread being picked up by the nozzle. After the threa has been looped it is seized and sheared oil by an upper clamp I 0, the waste end of the thread being drawn ofi in the suction tube. The upper clamp may be substantially identical with the corresponding clamp in the knotter of said Peterson patent. The actuating mechanism for the lower clamp H is, however, of somewhat different form than that of the Peterson knotter in view of the diflerent timing required in the present knotter. Furthermore a slack drawing hook l2, located just above the lower clamp II, is in the present device arranged to aid in actuating such lower clamp and is combined with other parts in a novel form of tensioning mechanism to exert a tension on the reserve thread, which varies in value at different periods in the knotting operation to match the requirements of the operations used in tying the novel knot herein contemplated. Consequently the lower clamp ll, slack drawing hook I2 and associated thread tensioning parts are described hereinafter in some detail in view of the novel structures involved. In the case of the upper clamp l0 and other such parts which are substantially duplicated from those shown in said Peterson patent, reference may be made to the latter for details of construction.

Generally stated, the upper clamp 10 is a shearing and gripping clamp. It not only grips the end of the thread, but also shears it off neatly adjacent the knot. The lower clamp H is, however, simply a gripping, rather than a combined shearing and gripping, clamp. These clamps are actuated in timed relation to each other and to the other parts of the knotter (see time chart Fig. 13). Moreparticularly, at least one and preferably both clamps remain open until the initial looping of the thread has been accomplished (see Fig. 8) in the knotting operation so that suflflcient slack will be available for this purpose. During this time the thread is tensioned sufficiently, to stay in place, by the slack drawing hook l2. This hook not only serves to tension the thread but also draws a little additional slack which is'released for knotting purposes after the clamps Ill and H are closed.

Of primary importance in carrying out the knotting operation is the maintenance of the threads in proper position and under requisite tension. The clamps serve to position the threads for this purpose and the slack hook I2, with its cooperating parts hereinafter described, adjusts the tension in the reserve thread automatically to suit the requirements of successive steps in the knotting operation.

To insure proper timing of the various actuating elements of the knotter mechanism they are all driven from a single rotatable cylindrical cam l3 (Figs. 3 and 4). This cam has suitably contoured individual cam tracks in both its end and side surfaces. The relative timing of the actuation of the different parts may be determined by reference to the time chart, Fig. 13.

The lower clamp II for the reserve thread (Fig. embodies a fixed jaw or finger I34 and a cooperating movable Jaw or clamping finger IS. The Jaw I4 is shown herein as an integral extension on a stationary plate It (see Fig. 2 in addition to Fig. 5). Similarly, the movable jaw l5 constitutes an integral extension on a plate II, which is pivoted on a stud l8 riveted. to the stationary plate l6 and is yieldably urged against the bottom face of the latter by a. compression spring I! encircling the stud l8.

As to the actuation of the lower clamp II for the reserve thread, initial movement of the swingable clamp jaw l5 from open position (Fig. 5) to an intermediate position in which it is"just ready to close (Fig. 5-) is accomplished in response to a retractive motio of the slack drawing hook i2. In this retrac ive or inward motion of the hook I2, slack is p lled in the bight of the reserve thread lying between the clamps I0 and H so that suilicieni; thread will be available for forming the doubly twisted loop in the knotting operation.

The slack hook I2 is fashioned onthe end of an arm 20, pivoted intermediate its ends at 2| and having a cam follower roller (not shown) on its inner end which is received in a cam track groove on the actuating cam l3. As the slack hook I2 is retracted it pulls a bight of the reserve thread a across a projection 23 (Fig. 7) on a plate 24 located at the upper surface of the slack hook. Furthermore, during this retraction of the slack hook I2 a cam plate 25 bolted to the hook arm 20 strikes a pin 26. This pin 23 is carriedby a curved link 21, pivoted at its upper end, and passes through a cam slot 28 in the movable clamp jaw plate l1. Accordingly, as the hook arm 20 continues its descent to the position of Fig. 5, the pin 28 rides along a cam surface 29 on the cam plate 25 and oscillates the clamp plate I! from its full open position (Fig. 5) to its intermediate but still open position (Fig. 5*). In this way the movable clamp jaw II is shifted to an intermediate point or position where it is Just ready to close during the time that the slack is being drawn for the knot by the slack hook l2.' It will be noted that the pin 24 has a flattened side 26' (Fig. 6) opposed to the cam plate edge 23.

Final closure of the lower clamp II is accomplished in response to a lateral shifting of a vertical knotter post 30 (see Fig. 2 as well as Fig. 5) which takes part in the knotting operation. This knotter post is both laterally and axially movable, being substantially identical in form and function with the corresponding part in said Peterson patent noted above. that the post 30 is carried on and shifted laterally by a pivoted arm 3| which is oscillated by the main driving cam l3. To achieve this final closure of the clamp I I in response to the movement of the knotted post 30, a stud 3| on the arm 3| which also carries the post 30 is utilized as a pivot for the link 21. Consequently, when the knotter post 30 is shifted laterally (upward as viewed in Fig. 5) by the corresponding movement of its supporting arm 3|, the stud 3| pulls up on the link 21 and drags the pin 23 about the nose of the cam plate 25 (Fig. 6). The shift of the post 30 to close the clamp carries the post from the position of Fig. 5 to that of Fig. 5'. By thus shifting the pin 26 to the right (as viewed in Fig. 5) the clamp jaw plate I! is oscillated to It may be noted here its fully closed position (Fig. 5'). By virtue of this timing the reserve threada can be freely drawn through the lower clamp l l during the initial looping of the thread in the knotting operation, and in this interval the slack hook I2 is retracted to tension the thread and to draw slack in the bight of the thread. Aftegr this slack is drawn the lower clamp I i is closed to hold the lower end of the bight firmly. Y

For the first step of the looping of reserve thread a in the actual knotting operation, a knotter hook 32 (Figs 2 and 8) is retracted axially inward (to the left as viewed in Fig. 8) and is simultaneously rotated in a counte clockwise direction, through substantially a full um and a half. In the course of this retractive ovement the hook 32 engages the bight of t e reserve thread a and the rotation of the hook twists the thread so as to form the main loop or for the final knot with the twisted portion atiat the base of this loop, which is utilized in obtaining the subsequent configuration of the threads as shown in Fig. 1' described above. The end as of the reserve thread is gripped by the upper shear clamp I!) while the standing part or of this thread passes over a vertically shiftable finger 33 and through the lower clamp H. The upper clamp i0 is timed to close at the end of this retractive and rotative movement of the hook 32 while the lower clamp i I closes just slightly later (see time chart, Fig. 13). Consequently, ample slack is available for the looping and twisting of the thread by the hook 32 during the hook movement just described.

Before proceeding to the next step in the knotting operation, attention may be given to the actuating mechanism for the knotter hook 32 (Figs. 2, 3 and 4) In this particular arrangement, the hook 32 is carried on the outer end of a rotatable and axially shiftable shaft 34, which is suitably journaled in the frame of the mechanism. Axial shifting of the shaft 34 is effected bymeans of an oscillatable lever 35 (Fig. 4) pivoted intermediate its ends at 36 and having a cam follower roller 31 on its inner end which rides in a cooperating cam groove in one end face of the actuating cam l3. A segment of teeth 38 on the opposite end of the lever 35 mesh with teeth 39 on the shaft 34, which may be conveniently spirally formed. Thus, as the lever 35 is oscillated by the rotation of the actuating cam I3, the knotter hook shaft 34 will be shifted axially in proper timed relation to the actuation of the other parts of the mechanism. Similarly, rotative movement of the hook shaft 34 is accomplished by means of a lever 40 (Fig. 3) pivoted intermediate its ends at 4| and having a cam follower roller 42 on one end thereof which is received in a complemental cam track groove in the side face of the actuating cam 13. For the sake of compactness it is desirable to accomplish the necessary rotation of the hook shaft 34 through its full turn and 'a half with a minimum of throw for the lever 40 and consequently a motion multiplication connection is provided between the lever 40 and the shaft 34. This connection includes a segmental series of teeth 43 on the free end of the lever 40 which mesh with a pinion 44. Fast on this pinion. 44 is a segment of teeth 45 of larger radius than the pinion and which in turn mesh with an elongated pinion 4i fixed on the shaft 34. In this way rotation of the knotter hook 32 on the end of the shaft 34 is also effected in timed relation of the actuation of the other knotter mechanism elements.

In the second principal step of the knotting operation the knotter book 32 is utilized to form a temporary loop in one of the strands forming the main loop or in the reserve thread a. and to draw this temporary or second loop through the main loop. To pull the loop a, over to the side of the shank of the hook 82 opposite the point of the hook, the knotter post or pin 30 is shifted laterally toward the reserve thread a from the position of Fig. 8 to that of Fig. 9.' The initial portion of this lateral shift of the knotter post It serves to finally close the lower clamp I I, as was previously described. During the lateral shift of the knotter post Ill just described, the slack hook I2 is moved outwardly slightly to provide sufiicient slack in the thread as it is pushed transversely by the knotter post (see time chart Fig. 13)

After the knotter post 20 has been shifted a sufiicient distance to clear the knotter hook 22, the latter is projected outwardly to the position of Fig. 9 so that the main loop in rides up on the shank of the hook. Furthermore, during the advancing movement of the hook 32 the finger 33 is elevated from its position shown in Fig. 8 to the dot-dash line position shown in Fig. 9 and then quickly dropped again to the full line position shown in Fig. 9. In this way the standing part a: of the thread a is dropped over the end of the hook 22. Thereafter the hook 32 is rotated in a clockwise direction through substantially 180, or a half turn, so that its nose can pass through the main loop in (Fig. 10). Finally, the knotter hook 32 is withdrawn to the position of Fig. 11, thereby drawing a second or temporary loop as through the main loop m. It should also be noted that in the course of this retractive movement of the hook 32 that it is re-rotated through substantially 180 in a counterclockwise direction so that the strands making up the loop as will not be crossed.

At this point in the knotting operation (Fig. 11) the reserve thread a is looped in what is in efiect a loose bowknot except that the strands of the main loop in of the knot are twisted through a full turn and a half rather than merely through a half turn as in a conventional bowknot. The temporary loop as constitutes, of course, the bow of the bowknot. I

Insertion of the second or exhausted thread b into the temporary second loop as in the reserve thread it, constitutes the third main step of the knotting operation. For this purpose an ex-' hausted thread hook 41 is projected laterally through the temporary loop as to the dot-dash line position shown in Fig. 11 in which it engages a bight in the exhausted thread b which is presented to the knotter at the proper time by a dow'n-take arm (not shown) like that of said Peterson patent. Thereupon the hook I! is retracted and draws with it a bight of the exhausted thread 6 through the loop as. This bight of the exhausted thread b is gripped between the hook 41 and a cooperating shearing clamp plate or jaw ll so that the exhausted thread is sheared off at this point and held with the thread extending through the temporary loop an in the reserve thread (Fig. 11)

In the fourth main step of the knotting operation, the temporary loop in the reserve thread is pulled back through the main loop or so as to dissolve this temporary loop and at the same time draw the reserve thread b through the main loop (:1 and leave the exhausted thread loop extending about the standing part a: of the re-' serve thread. To this end, the knotter hook 32 is thrust outwardly again past the post 30 so as to free the temporary loop as from it, and coincidentally tension is applied to the standing part a: of the reserve thread by the slack take-up hook i2. This amounts, of course, to applying tension to the running strand of the bow for the temporary bowknot described above. In this way. the standing part a: of the reserve thread is drawn back through the main loop 01 bringing with it the exhausted thread I: so that the threads occupy substantially the configuration shown in Fig. 12. Upon reference to this latter figure, it will be seen that the threads have now been looped in a modified form of loose weavers knot substantially like that of Fig. 1. The ends a; and ha of the reserve and exhausted threads are clamped as is the standing part b: of the exhausted thread. The standing part a: of the reserve thread a is also clamped and in addition tension is being applied to it by the slack knot l2 which has a further retractive movement at this point (see time chart Fig. 13)

Inthe fifth and final step of the knotting operation, the loops forming the knot are drawn tight and as an incident to such tightening of the knot the twisted portion at of the reserve thread is drawn through the loop in in the exhausted thread so that in the completed knot the threads will have the configuration of the novel doubly interlocked knot shown in Fig. 1. For this purpose the tension onthe standing part a: of the reserve thread is continued while the knotter post 30 is shifted axially downward to slip it free from the knot. It should be noted that this step of drawing a twisted portion of one thread within a loop in-the other is wholly novel and finds no counterpart in the conventlonal weavers knot.

Opening of the clamps I0 and Ii releases the reserve thread a at the completion of the knotting operation described above. The upper clamp I0 is actuated directly from the cam i3, just as in the case of the corresponding clamp in said Peterson patent heretofore noted, and is opened at the end of the described knotting operation by an actuating arm which is shifted by the cam I 3. The lower clamp Ii, however, is opened, in the present case. by a further and extreme lateral shift of the knotter post 30 to the position of Fig. 5. In the course of such lateral movement of the post 30 the link 21 is pulled upwardly (as viewed in Fig. 5") and the pin 26 rides along the outer end face of the cam plate 25. As a result, the pin 26 oscillates the clamp plate IT in a clockwise direction (as viewed in Fig. 5') so that the clamp finger I 5, on the plate I 1, is swung to its full open position (Fig. 5). when the knotter post SI comes to rest in its extreme laterally shifted position the pin 2 is seated in t e upper end of the slot 28, with the clamp plate I! and link 21 in the positions of Fig. 5. The arrangement of the parts issuch that the clamp II will remain open during the time that t e arm 20, which carries the cam plate 25 and slack hook l2, returns to its initial position (Fig. 5). As the arm 20 rises, the curved outer end face of the cam plate 25 rides past the pin 26 without changing the latters position. Similarly, upon the subsequent descent or return lateral movement of the knotter post 30, the pin 26 rides down the groove 28 and without shifting the angular position of the clamp plate I! about its pivot pin IS. The friction of the compression spring is, which encircles the pin i8, is sufiicient to overcome the friction of the pin 26 in the slot 2l,'during the descent of the pin 28 just noted, so that the position. As a result the parts all finally return to their initial positions shown in Fig. 5. In this same connection it will be noted that at a much earlier point in the cycle (see the time chart,.

Fig. 13) the clamp II also remains closed even though the knoter post 34 is returned from its intermediate position (shown in Fig. to its initial position (shown in Fig. 5). The clamp plate i1 remains immobile during this intermediate return motion or the knotter post 30 since the pin 25 rides down the slot 28 and again the spring It prevents angular movement or the clamp plate ll which would otherwise be caused by the friction of the pin 25 on the edges of the slot 25.

A diflerence in the tension placed on the reserve thread a, by the slack drawing hook I2, is desirable in difierent portions of the knotting operation. In particular, during the initial drawback of the knotter hook 32 the thread is in a position to 'withstand a substantial tension exerted by this knotter hook and the tensioning hook l2. Near the end of the knotting operation, however, when the hook I2 is retracted still further, to complete the drawing tight or the knot, the thread is not positioned to withstand tensioning so well. Accordingly, means has been provided in which two springs, or similar yieldable biasing members, are arranged so that slack is drawn against the resistance oi! both of these springs during the first .period mentioned and against the resistance or only one spring during the second period.

In the particular thread tensioning construction illustrated (Fig. '7), the plate 24 is pivoted on a pin 49 carried by a bracket 50. As the slack hook |2 descends it draws the reserve thread a across the projection 23 on the plate 24 so that the latter tends to swing in a counterclockwise direction (as viewed in Fig. 7). Swinging oi the plate 24 in this direction is yieldably resisted by a pair of contractile springs 5| and 52. The spring 5| is anchored at its outer end to a projection 53 on a fixed plate 54, which carries the bracket '55. Similarly, the inner end of the spring 5| is anchored to an arm 55 integral with the plate 24. It should be noted at this point that the arm 55 is notched as indicated at 55 so that the point of attachment for the spring 5| may be varied at will with a consequent change in the length of the moment arm about the pivot pin 49 through which the spring acts and, hence, a corresponding change in the biasing, torque exerted by the spring on the plate 24.

The second biasing spring42 has an indirect connection with the swingable plate 24 so that it is operatively connected thereto during only a portion of the period occupied by the complete knot tying operation. In particular, the outer end of the spring 52 is anchored to the fixed plate 54 by a pin 51. The inner end of the spring 52 is, however, anchored to an intermediate plate 58 pivoted by a pin 59 on the fixed plate 54. An abutment 50 on the pivoted plate 58 underlies the plate 24 so that during its downward motion the plate 24 strikes the abutment 55 and swings the pivoted plate 55 in a direction to tension the spring 52. A second abutment 5| is provided on the plate 55, however, and is located in the path of a part l2 oi the descending slack drawing hook l2 (Fig. 7). Consequently, when the latter approaches its lower extremity of movement it strikes the abutment 5| and swings the abutment 50 out of contact with the plate 24,

thereby interrupting the operative connection between the spring 52 and plate 24. Upon reference to the time chart (Fig. 13) it will be seen that this extreme motion of the slack drawing hook l2 takes place at a time close to the end of the knotting operation and during which the slack drawing hook is pulling the thread a to draw the loops or the knot tight and complete the same. By virtue of the arrangement described it will be seen that only the single spring 5| acts on the plate 24 during this final tensioning operation so that the tensioning force exerted on the reserve thread a is substantially diminished as compared to that in the initial knot tying operation during which both of the springs 5| and 52 act simultaneously to tension the reserve thread. The amount of tension provided for drawing the knot tight may be adjusted with nicety by changing the setting or the spring 5| so as to conform with the tensile characteristics of the particular type 01' thread or yarn being knotted.

In summary of the knotting operation, it will be seen that in general the threads are arranged as shown in Fig. 1* and then drawn tight to the final knotted arrangement of Fig. 1. In this final operation the twisted portion (14 of the thread a. is pulled within and squeezed by the main loop in in the thread b. In this way a doubly interlocked knot of extreme strength is formed. Preferably the threads are preliminarily arranged (in the configuration of Fig. 1*) for this important final step described above, by first forming a doubly twisted main loop a: in one thread a (Fig. 8), completing a temporary bowknot by drawing a bow or loop as through the main loop (Fig. 11)

inserting a second thread I) through the bow as (Fig. 11), and then tensioning the running strand a: of the bow so as to dissolve the bow and withdraw the thread b through the main loop or (Fig. 12). The continuation of tension in the strand a2, and withdrawal of the knotter post 30, achieves the final transformation step in which the threads shift position from that of Fig. 12 to that of Fig. 1, through the intermediate stages shown in Figs. 1' and 1. In the completed knot (Fig. 1), the portion at of the thread a is encircled and squeezed by the loop in to accomplish an extra interlock between the threads in addition to the interlocking loops and strands of an ordinary weavers knot. By virtue of this added interlock, a doubly interlocked knot is achieved which eiiectually unites even such springy material as wool strands.

Although a particular embodiment of the invention has been shown and described in some detail, there is no intention to thereby limit the invention to such embodiment and application, but on the other hand, the appended claims are intended to cover all other modifications within the spirit and scope of theinvention.

I claim as my invention:

1. The method of knotting together a pair of threads, which comprises, looping the threads together in the form or a loose weavers knot of conventional configuration for such a knot except that the end or one thread, which normally in a standard weavers knot projects between a portion of the same thread and the strands of a loop formed in the other thread, is instead twisted about said portion of the same thread and projects free of said other thread; and then drawing the knot tight and as an incident to such tightening drawing said twisted portion of said one thread through the loop in said other thread so that it is encircled and gripped by such loop.

resembles a loose single bowknot in one of the threads but in which knot the strands at the base of the main loop, through which the bow projects, are twisted about each other through substantially a full turn and a halt; inserting a second thread through the bow; tensioning the running strand of the bow to withdraw the bow through said main loop along with the second thread, which is inserted through it; and continuing the tensioning of such running strand until the final knot is drawn tight with the twisted strands at the base oi the main loop encircled by a loop in the second thread.

3. The method of knotting together a pair oi threads which includes the preliminary looping together of the threads in a modified form 01' weavers knot by first forming what generally resembles a loose single bowknot in one of the threads but in which knot the strands at the base or the main loop. h ough which the bow projects, are twisted about each other through substantially a full turn and a half: then insertlng a second thread through the bow; and tensioning the running strand of the bow to dissolve the bow and draw the second thread through said main loop with the second thread itself looped about one of the strands of such main loop.

4. A method of knotting together two threads in which, the threads arepreliminarily arranged with oppositely projecting loops formed in the respective ends 01' the threads and with the standing part of one thread extending through the loop in the other thread while the end of said one thread is twisted about said standing part and projects freely of. said last named loop. and with both the standing part and one end of said other thread projecting through the loop in said one thread, and then drawing the knot tight after such preliminary configuration of the threads and in such latter operation pulling said twisted portion of said one thread through the loop in said other thread.

5. The method of knotting together a pair of threads which comprises, forming a main loop in one thread with the strands constituting the loop twisted through substantially a turn and a half at the base of the loop, then forming a second loop in a standing part of the thread adjacent the main loop and drawing it through the main loop from the side of the latter opposite said standing part in which said second loop is formed, inserting a second thread through the second loop thus formed, withdrawing the second loop together with the inserted second thread.

whereby to dissolve said second loop and to form a third loop in said second thread encircling one of the standing parts of the first thread, and applying a tensioning force to said last named standing part of said first thread to draw said twisted base portion of said main loop through said third loop as an incident to the final tightening of the knot. I

6. The method of knotting together a pair of threads, which comprises, forming a main loop in one thread with the strands constituting the loop twisted through substantially a turn and a half at the base of the loop, then forming a second loop in a standing part of the thread adjacent the main loop and drawing it through the main loop from the side of the latter opposite said standing part in which said second loop is formed, inserting a second thread through the means for intertwining a pair second loop thus formed, and withdrawing the second loop together with the inserted second thread, whereby to dissolve said second loop and to form a third loop in said second thread encircling one of the standingparts oi the first thread.

7. A knotter comprising, in combination, means for forming a loose single bowknot in a first thread but with the strands of the main loop twisted through substantially a full turn and a half, means for inserting a second thread through the bow or the knot formed by said first named means, and means for tensioning the running strand of the bow to withdraw the bow through the main loop of the bowknot along with the second thread inserted through it and finally to pull the twisted base portion of the main loop within the resulting loop in the second thread as an incident to drawing tight the completed knot.

8. A knotter comprising; in combination, means for forming a loose single bowknot in a first thread but with the strands of the main loop twisted through substantially a full turn and a half, means'tor inserting a second thread through the bow of the knot formed by the first named means, and -means for tensioning the running strand of the bow to dissolve the bow and draw the second thread through the main loop with the second thread itself looped about one of the strands 01 such main loop.

9. A knotter comprising, in combination, means including a rotatable hook engageable with a bight in a first thread for'forming a loop in such thread with the strands at the base of the loop twisted through'substantially a first turn and a half, means for positioning one of the twisted strands for engagement by the hook to form a second loop in said one thread extending through the first loop, means for inserting a second thread through the second loop, and means for tensioning one of the strands of the first thread to draw the twisted base portion of the first loop within a loop formed in the second thread as an incident to the withdrawal of the second thread and the second loop through the first loop.

10. A knotter comprising, in combination, means for looping a thread with the strands of the loop twisted about themselves and for drawing one of the strands through the loop in the manner of a bow in a bowknot, means for inserting a second thread through the bow, and means for tensioning the running strand of the bow to dissolve the latter and to pull the second thread into a loop interlocked with a strand of the main loop and finally to draw the twisted portion of the first thread within the loop in the second thread as an incident to completion of the tightening of the knot.

11. A knotter comprising, in combination, means for intertwining a pair of threads in the form 01' a knot, means for tensioning at least one of said threads during a plurality of periods in the knotting operation of said first named means, and means operable in timed relation to the first named means for varying the tensioning i'orce produced by the second named means.

12. A knotter comprising, in combination, of threads in the form or a knot, means including a pair oi. relatively movable tensioning members adapted to receive at least one oi the threads therebetween to tension the same by relative movement between said members,

means including apair of yieldable resilient members for resisting movement of one of said tensioning members, and means responsive to a predetermined relative movement between said tensioning members for rendering at least one of said resilient members ineflective thereafter to resist movement of said one tensioning member.

13. A knotter comprising, in combination, means for intertwining a pair of threads in the form of a knot, a pivoted plate arranged to have at least one of the threads led over an edge thereof, a hook at one side of said plate disposed to move past the adjacent plate face to tension such thread by pulling it across said plate edge, said plate being movable about its pivot in the direction of hook movement, means including a plurality of springs for yieldably biasing said plate to swing about its pivot in a direction to tension the thread, and means responsive to a predetermined movement of said hook in one direction for rendering at least one of said springs ineifective to bias said plate during further movement of said hook in said one direction.

14. A knotter comprising, in combination, means for intertwining a pair of threads in the form of a knot, a pivoted plate arranged to have at least one of the threads led over an edge thereof, a hook at one side of said plate disposed to move past the adjacent plate face to tension such thread by pulling it across said plate edge, said plate being movable about its pivot in the direction of hook movement, means including a pair of springs for yieldably biasing said plate to swing about its pivot in a direction to tension the thread, means responsive to a predetermined movement of said hook in one direction for rendering one of said springs ineffective to bias said plate during further movement of said hook in said one direction, and means for adjusting the torque applied to said plate by the other spring.

15. A knotter comprising, in combination, means for intertwining a pair of threads in the form of a knot, a pivoted plate arranged to have at least one of the threads led over an edge thereof, a hook at one side of said plate disposed to move past the adjacent plate face to tension such thread by pulling it across said plate edge, said plate being movable about its pivot in the direction of hook movement, a spring for yieldably biasing said plate to swing about its pivot in a direction to tension the thread, a second member pivoted for movement about an axis coincident with that of said plate, said plate and second member being fashioned with portions engageable upon movement of said plate in a direction to relieve the tension in the thread, a second spring for biasing said second member for movement in a direction to cause engagement of it with said plate and toswing the latter to tension the thread, and means including interengaging portions of said hook and second member for causing the hook to move said second member out of engagement with said plate after a predetermined movement of said hook in a thread tensioning direction.

16. In a knotter mechanism embodying a laterally shiftable knotter post and a movable slack drawing member, the combination of a thread clamp comprising a pair of relatively movable clamping jaws, and means responsive to movement of the slack drawing member for shifting said jaws relatively to each other from a full open position to an intermediate although still open position, said last named means being responsive to a lateral shift of the knotter post for closing said jaws from such intermediate position.

17. In a knotter mechanism embodying a laterally shiftable knotter post and a movable slack drawing member, the combination of a thread clamp comprising a pair of relatively movable clamping jaws, and means responsive to the movement of the slack drawing member for shifting said jaws relatively to each other from a full open position to an intermediate although still open position, said last named means being responsive to an initial lateral shift of the knotter post in one direction for closing said jaws i'rom such intermediate position and responsive to a further shift of the knotter post in the same direction for reopening said jaws.

18. In a knotter mechanism the combination with a movable knotting device engageable with a thread to be tied, of a thread clamp comprising a pair of relatively movable clamping jaws, and means responsive to a movement of said device in one direction for closing said jaws and responsive to a further predetermined movement of said device in the same direction for reopening said jaws. 1 a

19. In a knotter mechanism the combination with a movable knotting device engageable with a thread to be tied, of a thread clamp comprising a pair of relatively movable jaws, means responsive to a movement of said device in one direction for closing said jaws and responsive to a further predetermined movement of said device in the same direction for reopening said jaws, and means for retaining said jaws'in, their reopened position during a return of said device to its initial position.

20. In a knotter mechanism the combination of, a laterally shiftable lever having a knotter post mounted thereon, a movable slack drawing device, an actuator arm for saiddevice, a fixed thread clamping jaw and a cooperating pivoted jaw having a slot therein, a pin in said slot, means on said actuator arm for camming said pin in a direction to pivot said movable jaw toward closed position in response to movement of said actuator arm, and means including a link pivoted at one, end on said lever and carryingsaid pin on the other end for pivoting said movable jaw still tur ther and into fully closed position in response to a lateral shift of said lever carrying said knotterpost.

HARRY G. LIND.