US2128896A

US2128896A - Knotter

Info

Publication number: US2128896A
Application number: US63541A
Authority: US
Inventors: Edward J Abbott
Original assignee: Abbott Machine Co Inc
Current assignee: Abbott Machine Co Inc
Priority date: 1936-02-12
Filing date: 1936-02-12
Publication date: 1938-09-06
Anticipated expiration: 1955-09-06

Description

Sepit. (:3, 1938. E. J. ABBOTT 2,328,896

KNOTTER Original Filed Feb. 12, 1956 5 She.etsSheet 1 Sept. 6, 1939 E. J. ABBQTT 2,12,8Mi

KNOTTER Original Filed Feb. 12, 1936 5 Sheets-Sheet 2 E. J. ABBOTT Sept. 6, 1938 KNOTTER Original Filed Feb. 12, 1956 5 Sheets-Sheet 5 Patented Sept. 6,1938

UNITED STATES Edward J. Abbott, Wilton, N. 11., assignor to Abbott Machine Company, Wilton, N. 11.. a corporation of New Hampshire Application February 12, 1938, Serial No. 63.541 Renewed November 29, 1937 31 Claim.

. strands includes a formation in which one strand,

conveniently referred to as the first strand, has an end portion which forms a bight about the second strand and lies back against itself forming a tail which protrudes from the knot in contact with and generally parallel to thefirst strand. 1

One objegt of the invention is to provide mechanism for positioning, cutting oil. and holding the strand which forms this tall in such manner that the knot will be thoroughly tightened and that the length of this tall will be accurately determined and can-be made quite short. More particularly, the invention aims to provide a knot tyer in which the knot is formed by rotation of one tying bill, and in which the strand destined to form the aforesaid generally parallel tail of a weavers knot is caught, out and held by a device,

preferably another tying bill, which moves with portion at the time of stripping the knot, thereby cooperating in the tightening of the stripped knot. A further object is to provide a simple and reliable mechanism for correlating the action of a knot-forming tying bill and such de- I vice for catching, cutting and holding the end which forms the aforesaid generally parallel tail of the knot.

Another object of the invention is to provide an improved form of mechanism, applicable to knotters generally but particularly suited to a .weavers knotter, adapted to position strands in a doubly-crossed formation, form a loop from these doubly-crossed strands, catch and hold the parts of the strands destined to form tails, cast oi? the loop comprised of the doubly-crossed strands over the severed end of one of the tails and draw the knot tight. A further object of invention is to provide an improved form of strandcrossing mechanism adapted to receive two strands, twist these together by rotation through an arc of 360, and upon the completion of such rotation let the strands be free to leave the element which accomplished their twisting together.

Another object of the invention is to provide improved knotter-actuating mechanism, of general applicabiliy but of special utility in connection with the automatic actuation of a knotter in a machine, and also of special utility in conpredetermined position ready for a subsequent cycle of operations.

Other objects of invention and features of advantage and utility will be apparent from this specification and its drawings, wherein the invention is explained by way of example.

In the drawings:

Fig. 1 is a plan view of a knotter, according to this invention with its actuating mechanism and cam-cover omitted;

Fig. 2 is a side elevation of the knotter of Fig. 1;

Fig. 3 is a side elevation of the knotters back plate showing also the parts attached thereto;

Figs. 4 to inclusive are diagrammatic views,

in perspective, showing in steps the action of the crossing mechanism, bills and stripper in forming and tightening a knot;

Fig. 11 is an end elevation of the knotter, showing particularly the actuating mechanism of the knotter, this being shown in its inactive position;

Fig. 12 is a fragmentary view taken from the same point of view as Fig. 11, but showing the knotter-actuating mechanism in the act of driving the knotter; and

Fig. 13 is a vertical sectional view on the line l3l3 of Fig. 11.

Referring to Figs. 1, 2 and 3, the illustrated knotter is provided with a suitable strand guide 20 having a slot 2| in which one strand, which for convenience is referred to as the first strand and indicated in Fig. 4 by the reference character :r, is adapted to lie, and an edge 22, against which the second strand, indicated in Fig. 4 by the reference character 3 is adapted to lie. Mechanism indicated generally at 24, on the back of the knotter, constitutes a further strand guide for both the strands, and a function of these guides is to receive a pair of strands brought thereto either mechanically or manually, and to position these strands for the intended operation thereon of theloop-forming, strand-severing and knot-stripping devices.

The preferred and illustrated form of means for forming the loop which becomes a knot of the two strands is shown as comprising a rotary loop-forming tying bill 25, having fixed blades 21, 28 (see Fig. 10) and a cutting and holding blade 29 pivoted to the bill at 30 and equipped with extensions 3i and 32, serving as cam-followers to open and close the bill. The strand guides just mentioned are so arranged and shaped with reference to the loop-forming bill 26 as to cause the second strand 1/ to be initially received by the shank of this bill, as indicated in Fig. 4.

For the purpose of positioning, grasping and cuttingthe end of the first strand, destined to form the tail which protrudes from the resultant knot generally parallel to and in contact with of. the loop-forming means. vantage in causing the consequent formation of a true weavers knot rather than the so-called this strand, the invention provides a mechanism herein shown in its preferred form as a further rotary bill 35 rotatable about the same axis as the loop-forming bill 28 but oppositely directed. As best indicated in Fig. 8, bill 35 has fixed

blades

31 and 38 and a cutting and holding blade 38 pivoted thereto at 40, and equipped with camfollower extensions 4| and 42 similar to those of the other bill. The relation of the strand guides to bill 35 is such as to guide the first strand a: to the outer side of the bill blades keeping the strand clear of the bill shank, as shown in Fig. 4.

The above-described arrangement of bills is adapted for mounting in a simple U-shaped frame (Figs. 1 and 2), the

respective bill shafts

45 and 41 being rotatable in the opposite

vertical elements

48 and 48 of the frame and driven through sets of gears 58, 5| and 52, 53, from a common drive shaft 54, which is also mounted in the opposite

vertical frame elements

48 and 48. Driving gears 5| and are both twice the diameter of the respective driven

gears

58 and 52, so that one revolution of drive shaft 54 causes two revolutions of bills 25 and 35. Figs. 1, 2, 3 and 4 show the elements of the knotter in their initial or starting position.

Crossing of the strands The strand-crossing mechanism is shown as comprising a circular disk 51 having on its periphery teeth 58 between pairs of which there extend open slots 58, 5| adapted to receive the first strand, :2, and the second strand, 3;, respectively. A back plate secured to the U-shaped frame member 45 is suitably recessed to receive this circular disk 51 and to provide a converging mouth to facilitate entrance of the two strands into the slots 58 and GI. The disk 51 is further held in position by a pair of plates 51, 58 secured to the back plate 55 and suitably recessed to form a bearing for the disk 51 and to receive its teeth 58. A portion of the series of teeth 58 at the bottom of the disk 51 is exposed and meshes with a segmental driving element 58 pivoted at 18 to the back plate. A link 11, pivoted to the segmental element 58 at 12, is pivoted at 13 to a second link 14 which is pivot-ally mounted at 15 to the back plate 55. A cam follower 15 on link 14 engages a cam groove 18 on a cylindrical cam -18 which is fast on the main shaft 54. The

shape of cam groove 18 is such that at the start of a tying operation, the disk 51 is quickly turned through an angle of 360. Fig. 5 shows this turning movement, the disk 51 turning in the direction of the arrow 2, and Fig. 6 shows this 360 rotation of the plate 51 as completed before the bills 25 and 35 have rotated a quarter turn. The strands, as indicated in Fig. 6, are thus arranged so that each strand crosses the other twice, the crossings being close together and on the same side This is of adgranny species of weavers knot.

Forming the loop which becomes the knot and severing and clamping the tail of the second strand by further rotation forms the strands into a loop inclusive of the crossed portions thereof. Th

two strands of the loop are each bent around the other, the loop around the tying bill 28 consisting of lnterengaging bends of both of the strands, as clearly indicated in Fig. 7. Upon reaching the position of Fig. 7 the pivoted cutter blade 28 has been opened inwardly of the bill by the camming action of a cam-shaped plate 80 (Figs. 1 and 2) upon the extension 32 of this blade, and further rotation of the bill to and beyond the position of Fig. 8 causes the second strand 1! to be engaged :etvgen this pivoted blade 28 and the fixed blades By the time the position of Fig. 9 has been reached, the pivoted blade 28 has been closed by the camming action of the cam plate 88 on its extension 31, and the second strand 1/ thereby sheared and clamped. The clamping of the second strand 1 by the blades of the bill 25 results in inclusion or insertion of the tail portion of this strand 1! inside of the knot-forming loop when the latter is stripped off the bill as now to be described.

Stripping the knot A stripper arm in the form of a bell crank 84, pivotally mounted on the back plate 55 at 85, is normally in the full line position of Figs. 2 and 3, wherein its hook-shaped end "lies below the level of the bottom of the yarn slot 5|. A cam follower 81 on the bell crank stripper arm engages a cam groove 88 in the cam 18. The shape of this cam groove 88 is such that the cam follower 81 and stripper arm dwell in their full line position of Figs. 2 and 3 until just before the bills reach the position of Fig. 9, whereupon the stripper arm is raised to the dotted line position of Fig. 3, causing the hook 85 to engage the second strand g, pull it out of the groove 5| of the disk 51, further pull it to strip the knot-forming loop oil bill 25 over the severed and held end of the second strand y, and further pull it to tighten the knot and drag the severed end out from between the blades of the bill.

The knotter herein illustrated is particularly adapted to beemployed in automatic winding machines such as disclosed in the patent application of Edward J. Abbott and Joseph E. Ring,

. Serial No. 726,524, filed May 19, 1934, and in the patent application of Edward J. Abbott for Automatic winder, Serial No. 63,542, filed concurrently with this application. Any suitable abutment for the yarn g may beprovided exteriorly of the knotter to provide a frictional hold on the yarn g to facilitate tensioning the part between the hook 85 and the bill 25. For example, any suitable part of the winding machine or automatic magazine with which the knotter is associated mayhave a bar, rod, or the like I30 which will overlie the strand 1! at a point beyond the plate 51 to facilitate tensioning the strand by the hook 85. Or, if desired, the hook-shaped element 85 may be supplemented by cooperating clamps and actuating mechanism to cause the strand engaged by hook 85 to be clamped as it is pulled,

after the manner of several known forms of knot ters, for example, as indicated in the United States patent to Edward J. Abbott, No. 1,868,682. Or, in using a knotter according to the present invention as a hand-operated knotter, the operative can hold the two strands exteriorly of the knotter as usual, therey facilitating tightening of the knot when hook 85 rises.

Positioning, severing and clamping the tail of the first strand As indicated above, the preferred form of V it to a stop.

2,12e,eoe

means for positioning the first strand and forming and holding its tail is shown as constituted of the rotary bill 35. The pivoted cutting blade 30, initially held closed by the action of its camfollower extension 42 of a cam-shaped plate 00 (Figs. 1 and 2), becomes open at the position of Fig. 7 by the action onits extension 4| of the same cam-shaped plate 90, the pivoted blade 39 opening outwardly away from the remainder of the bill. The first strand :2 extending from the loop-forming bill 26 to guide slot 2I lies in the path of the now open bill 35, as indicated in Fig. 8. Further rotation of the bills causes the camfollower extension 42 of cutting blade 39'to en- The pull of the stripper hook 86 in tightening the knot is resisted in part by each of the tails of the knot held in

bills

26 and 35, until the stripped knot of Fig. 9 straightens out into a true weavers knot and becomes tight, whereupon both tails are pulled from their bills simultaneously. By thus employing clamping means, such as exemplified by the two bills, to hold and apply tension to both tails until the knot is tight, it is assured that the knot will be correctly and securely tightened. The tail-severing and clamping action of the bill 35 moreover enables the first tail to be quite short, since the bill 35, moving with the knot-forming bill 26 and acting -simultane ously therewith, is substantially no farther from the finally stripped knot than is the knot-forming'bill 26, and the tail of the first strand will therefore normally be substantially as short as that of the second strand 3 Return of parts to starting position Following the discharge of the tightened knot by the

bills

26 and 35, these bills complete the remainder of their second full rotation to the starting position of Figs. 1, 2 and 4, and during this idle movement of the bills, the cam 79 acts to restore the stripper arm 84 and its hook 86, and the segmental plate 60 and the strand-crossing plate 57 to their initial positions, ready for another operation.

Actuatz'ng mechanism be in the form shown and described in the pat-' ent application of Edward J. Abbott for Knot tyer, Serial No. 63.5.40 filed concurrently herewith, such actuating mechanism being adapted to rotate the shaft one full revolution and to bring For the use of the present knotter in the auto- .matic winding machine of the patent application of Edward J. Abbott and-JosephE. Ring, Serial N0. 7

'726',524,,wh erein there is provided an electrical circuit designed to initiate actuation of the knottenthere can. be employed the actuating I --mechanisin of Figs. 11,12 and 13 of the present application. Referring to these figures, the .actu'-' ating mechanism is provided with a frame 500,

its armature I05 extending down through a hole knot.

in the top of frame I00. A rack I06 connected to the lower end of the armature I05 terminates in a piston I0'I near the bottom of a cylinder I08.

Actuation of the solenoid I03 when an electric' current is applied to its terminals raises the armature I05, rack I 06 and piston I01. Both the upward movement of the piston and rack when the solenoid is energized and their downward movement when the solenoid is deenergized are cushionedby the cylinder I08, which is closed below the. piston I01 except for a leak passage IIOa controlled by an adjustable valve IIO. Upward movement of the rack I06 rotates a pinion II2 which forms partof a one-tooth ratchet-wheel I I3 loosely mounted on a reduced diameter portion II5 of shaft 54. A wheel II6 keyed to shaft 54 carries a pawl II I adapted to engage the tooth of ratchet-wheel II3, with'the result that an upward stroke of the solenoid armature I05 and rack I 06 acts through the pinion II2, ratchet-wheel II3, pawl Ill and wheel I I6 to rotate the shaft 54. one revolution, Fig. 12 showing the parts so moving in the directions of the arrows U, V, W, thereon. Upon the solenoid becoming deenergized, the armature and rack fall, the pawl III moving backward over the rachet-wheel II3. A pawl I I9, pivoted at I20 to the knotter frame.and a cooperating stop shoulder I22 on the wheel II6. are preferably provided to check a tendency of the wheel I I6 and shaft 54 to be turned-backward, and this pawl 'I I9 and stop shoulder I22 are positioned with reference to each other so as to retain the shaft 54 in its position corresponding to the initial position of the bills and other parts of the knotter. Thus it is assured that the knotter will be ready to receive the strands and tie them without having to turn idly in a reverse direction after each tying operation.

Certain of the structure shown and described in this application is within the scope of generic Y claims of an application of Edward J. Abbot for Knot tyer, Serial No. 63,540, filed concurrently herewith, and none of the features of that application are intended to be claimed herein.

It should be understood that the present disclosure is for the purpose. of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

- I claim:

1. A device for tying a weavers knot in two strands, comprising means for .positioning the strands to be tied, and means for forming a weaver s knot in saidstrands comprising two rotary bills.

2. A knot tyer having therein a rotary tying bill adapted to make a knot-forming loop in a pair of strands arranged in its path, means for tightening the knot including means for pulling the knot-forming loop from the bill, the bill be-' ing adapted to sever one of the strands and hold it while the knot-forming loop is pulled off over the held end, in combination with a rotary strandsevering and holding device cooperating with the tying bill and positioned with relationto the other strand'not severed bythe loop-making tying bill to sever and holds'aid other strand without making another knot-forming loop therein, said severing and holding device being timed to rotate inv proximityto the aforesaid bill during the making of the knot-forming loop and to retain a hold on said other strand. duringthe tightening of the 3. A knot tyer having therein a rotary. tying bill adapted to make a knot-forming loop in a pair of strands arranged in its path, means for tightening the knot including means for pulling the knot-forming loop from the bill, the bill being adapted to sever one of the strands and hold it while the knot-forming loop is pulled ofi over the held end, incombination with a second rotary bill cooperating with the loop-making tying bill and engaging only the other strand not severed by the loop-making tying bill, said second bill being so timed with relation to the first bill as to hold its strand during the tightening until the knot-forming loop has been pulled from the first bill.

4. A knot tyer having therein a rotary tying bill adapted to make a knot-forming loop in a pair of strands arranged in its path, meansfor tightening the knot including means for pulling the knot-forming loop from the bill, the bill being adapted to sever one of the strands and hold it while the knot-forming loop is pulled off over the held end, in combination with a second rotary bill cooperating with the loop-making tying bill and positioned with relation to the other strand not severed by the loop-making tying'bill to sever and hold said other strand without making another knot-forming loop therein, said second bill being so timed with relation to the first bill as to hold its strand during the tightening of the knot.

5. A knot tyer having therein twocooperating rotary devices each adapted to hold and sever a strand, means for disposing the strands to be tied in position for both of said strands to be made into a knot-forming loop by only one of said rotary devices and for the two tail-forming portions of said loop to be caught, held and severed by respective ones of said two rotary devices, means for tightening the knot including means for casting oil the knot-forming loop from its said rotary device over the tail of the strand severed by that device, means for rotating said two rotary devices in unison, and means for causing the two rotary devices to discharge the severed tails of the knot at substantially the same location in their cycle of rotation, the knot-tightening means being timed to tighten the knot while the two tails thereof are held by said respective rotary devices.

6. A knot tyer having therein two cooperating rotary bills each having blades adapted to hold and sever a strand, means for disposing the strands to be tied in position for both of said strands to be made into a knot-forming loop by only one of said bills and for the two tail-forming portions of said loop to be caught, held and severed by respective ones of said two cooperating bills, means for tightening the knot including means for casting oii the knot-forming loop from its bill over the tail of the strand severed thereby, means for rotating the bills in unison and means for operating the blades of the two bills in timed relation such as to discharge the two, tail portions at substantally the same location in the cycle of bill rotation, the knot-tightening means being timed to tighten the knot while the two tails thereof are held by said respective rotary devices.

7. A knot tyer having therein a pair of rotary bills disposed adjacent to each other and each having cooperating fixed and pivoted blades adapted to hold and sever a strand, means for rotating the bills in unison, and means for operating the blades during such rotation, one bill having its pivoted blade arranged to open by .inward movement and the other bill having its pivoted blade arranged to open by outward movement with respect to the bill shank.

8. A knot tyer having therein a rotary tying bill, means for twice crossing a pair of strands in the path of the bill, 'said crossing means including a rotatable member adapted to receive end of the strand caught by said bill.

9. A knot tyer having therein a rotary tying bill including a shear blade, means for twice crossing a pair of strands in the path of the bill, means for rotating the bill to make a knot-form? ing loop of the twice-crossed strands, means for retaining one strand in position for it to be caught, severed andheld by the bill, a second rotary bill including a shear blade for severing the other strand, means for closing the blades of the bills upon their respective strands and means for casting the aforesaid loop off the bill over the severed end of the strand caught by said bill.

10. A knot tyer having therein a pair of rotary bills each having cooperating blades, means for rotating the bills in unison, means for opening and closing the blades, strand-crossing and guiding means for disposing the strands to be tied in a doubly-crossed formation in the path of one bill where it is in a closed state, and for disposing both strands in position to be intercepted thereafter by the respective bills while they are in an open state, and means for casting off the knotforming loop thus formed when both'bills subsequently close.

11. A knot tyer having therein a pair of rotary bills having strand-severing blades, means for rotating the bills in unison, means for opening and closing the blades, a rotary element adapted to receive a pair of strands at one side of the blades, means for rotating the said element sufliciently to cross the two strands twice in the path of one of the bills where the latter is closed, so that further rotation of the said bill loops the crossed strands, guide means on the opposite side of the bills from said rotary element for securing the association for imparting substantially a full revolution to said rotary element to cross the strands twice in the path of said bill.

13. A knot tyer having therein a rotarytying bill, a rotary strand-crossing element at one side of the bill, said strand-crossing element comprising a disk having a pair of strand-receiving slots, and means for imparting substantially a full revolution to said rotary element to cross the strands twice in the path of said bill.

14. A knot tyer having therein a rotary tying bill, a side frame element, a rotary disk associated with the side frame element, said disk having slots to receive a pair of strands, and means operating in timed relation to the tying bill to rotate said disk substantially a full revolution to cross the strands twice in the path of said bill.

15. A knot tyer having therein aloop-forming device and means for positioning two strands for loop-formation by said device, said positioning means including a rotary element having recesses to receive a pair of strands and means adapted to impart to said element substantially a full revolution, to cross the strands twice.

16. A knot tyer having therein a'loop-forming device and means for positioning two strands for loop-formation by said device, said positioning means including a rotary disk having two slots, and a driving element adapted to impart substantially a full revolution to said rotary element, said disk having teeth adjacent to its periphery and said driving element having teeth meshing therewith.

1'7. A knot tyer having therein a loop-forming device and means for positioning two strands for loop-formation by said device, said positioning means including a rotary element having teeth at its periphery, a toothed driving element meshing with said teeth of the said rotary element, said rotary element having a pair of slots extending inwardly from spaces between pairs of said teeth to receive a pairof strands.

18. A knot tyer having therein a drive shaft, a rotary tying bill and a cam driven by the shaft, a rotary element adapted to receive two strands to be tied by the bill, and means whereby rotation of the cam through the initial part of rotation of the bill rotates the said rotary element substantially a full revolution.

19. A knot tyer having therein a drive shaft, a rotary tying bill and a cam driven by the shaft, a rotary element having two. slots to receive a pair of strands to be tied by the bill, teeth adjacent to the periphery of said rotary element, and a toothed driving element meshing with the teeth of said rotary element and driven by said cam.

20. A knot tyer having therein a motor device, a rack reciprocated thereby, a pinion rotated by the rack, a knotter-operating shaft, and a oneway driving connection between the pinion and the knotter-operating shaft, whereby operation of the rack in one direction operates the knotter shaft and the rack is capable of return movement without operating said shaft.

21. A knot tyer having therein a motor device, a rack reciprocated thereby, a pinion rotated by the rack, a knotter-operating shaft, and apawl and ratchet connecting the pinion and the knotter-operating shaft, whereby operation of the rack in one direction operates the knotter shaft and the rack is capable of return movement without operating said shaft.

22. A knot tyer having therein an oscillatory driving element, a knotter-operating shaft, a rotary tying bill operated by said shaft, a one-way driving connection between the oscillatory element and the shaft, permitting the driving element to rotate the shaft and knotter bill upon movement of said element in one direction, and means for checking backward rotation of the knotter-operating shaft.

23. A knot tyer having therein a solenoid, and a solenoid armature, a rack reciprocated by the armature, a knotter-operating shaft, a rotary tying bill operated by said shaft, a one-way driving connection between the armature and the shaft, permitting the armature to rotate the shaft and knotter bill upon mo ement of the armature in one direction, and means for checking backward rotation of-the knotter-operating shaft at the position corresponding to the starting position of the knotter bill.

24. In combination, in a knot tyer, means for forming a weavers knot, means for simultaneously severing the two strands to form knot tails, said severing means including cutting and clamping bills rotatable during the tying of the knot, and knot-tightening means acting to pull the tails from the bills simultaneously.

25. A weavers knot tyer comprising means for forming a loop which includes two strands in the form of interengaging bends of both strands, means for simultaneously severing the two strands to form tail portions, said severing means including cutting and clamping bills rotatable during the tying of the knot, and means for tightening the loop about one only of the tail portions.

26. A weavers knot tyer comprising means for arranging two strands in doubly crossed formation, means for looping the thus-arranged strands, means for simultaneously severing the two strands to form tail portions, said severing means including cutting and clamping bills rotatable during the tying of the knot, and means for tightening the loop about one only of the tail portions.

27. In combination, in a knot tyer, means for forming a weavers knot and means for tightening the knot including means comprising two rotary bills acting to hold the two tail portions of the knot until the knot is tight.

28. In combination, in a knot tyer, means for forming a weavers knot, and means for tightening the knot including clamping and severing devices acting on the two tail portions of the knot to hold them both under tension until the knot is tight, the clamping and severing devices comprising rotary bills.

29. A weavers knot tyer comprising means for forming a loop which includes two strands in the form of interengaging bends of both strands, means for forming tail portions, the tyer including rotary clamps for the respective tail portions, one of said clamps being arranged to retain its tail portion in position to be received within the loop and the other of said clamps being arranged to retain its tail portion in posi tion not to be received within the loop, means for closing said clamps approximately simultaneously during their rotation, and means for applying tension to both clamped tails until the knot is tightened and the tails thereby pulled from the clamps.

30. A weavers knot tyer comprising means for forming a loop which includes two strands in the form of interengaging bends of both strands, means for causing one only of the tail portions to be received within the'loop, the knot tyer including means for tightening the knot, including rotary clamps operative to hold both tail portions of the knot until the knot is'tightened, and means for closing said clamps approximately simultaneously during their rotation.

31. A knot tyer comprising means for forming a loop which includes two strands in the form of interengaging bends of both strands, means for causing a tail portion of a strand to be received within the loop, the knot tyer including means for tightening the knot including sepcrate-rotary clamps operative to hold both tail portions of the knot until the knot is tight, means for rotating the clamps in unison, and means for closing said clamps approximately simultaneously during their rotation.

EDWARD J. ABBUI'I.