US3854505A

US3854505A - Shuttleless loom grippers

Info

Publication number: US3854505A
Application number: US00355008A
Authority: US
Inventors: J Duplessy
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-04-27
Filing date: 1973-04-27
Publication date: 1974-12-17
Anticipated expiration: 1991-12-17
Also published as: FR2181615B1; CH569112A5; ES414121A1; JPS4947663A; IT984217B; GB1399956A; FR2181615A1; DE2321105A1

Abstract

Loom on which the insertion of the weft thread into the shed is performed by two rapiers which, starting from two opposite sides, meet in the middle of the shed where the one, called the ''''feed gripper,'''' transfers to the other, called the ''''take-off gripper'''' B, the weft thread which it has pulled from a fixed supply located on the side of the loom, characterized in that the gripper (A, B) of at least one of the rapiers is a gripper with pivoting arms (9, 55) arranged substantially in the manner of a cloth gripper, the front arms (23, 25) of which, forming a pressure tip which a spring (20, 68) tends to close, are directed toward the front of the rapier, while the rear arms (18, 81), the reciprocal drawing together of which causes the opening of the pressure tip, cooperate with a notch (43, 58) of a mobile drive element (37, 52) capable of interlocking, preferably by means of a spring (47, 56), on the front arms, which have been brought together, to keep the tip of the gripper open.

Description

nited States Patent 1 1 1 3,854,505 Duplessy 1 Dee-17, 1974 SHUTTLELESS LOOM GRIPPERS [76] Inventor: Jean Duplessy, Le Sommet, bis, ABSTRACT rue Simon, Loom on which the insertion of the weft thread into y France the shed is performed by two rapiers which. starting [22] Filed: APE 27 1973 from two opposite sides, meet in the middle of the shed where the one, called the feed gripper, transl l PP N05 355,008 fers to the other, called the take-off gripper" B, the

weft thread which it has pulled from a fixed supply [30] Foreign Application Priority Data cated on the side of the loom, characterized in that the gripper (A, B) of at least one of the rapiers is a Apr. 27, 1972 France 72.15999 g pp with p g arms arranged Substam tially in the manner of a cloth gripper, the front arms (23, 25) of which, forming a pressure tip which a [58] Fie'ld 139/122 N spring (20, 68) tends to close, are directed toward the front of the rapier, while the rear arms (18, 81), the [56] References Cited reciprocal drawing together of which causes the opening of the pressure tip, cooperate with a notch (43, UNITED STATES PATENTS 58) of a mobile drive element (37, 52) capable of in- 3,390,707 7/1968 Scherillo 139/122 terlocking, preferably by means of a Spring (47, 56). 3,602,266 8/1971 Duplessy 139/122 on the from arms, which have been brought together Primary E.\'aminerHenry S. .laudon Attorney, Agent, or FirmDowell & Dowel] B as 52 E 71 to keep the tip of the gripper open.

8 Claims, 15 Drawing Figures PATENTEUZEEIYIQM 3.854505 SHEET 10? 5 dig-1 86 K M a SHUTTLELESS LOOM GRIPPERS DESCRIPTION OF THE INVENTION The present invention concerns filling carriers for shuttleless looms with two rapiers, that is, those in which the weft thread is caught by its end at the beginning of a reserve supply held by grippers called the feed gripper placed at the tip of the first rapier to be conveyed up to the shed and to be taken in relay by another gripper called the take-off gripper located at the point of the second rapier which draws it through the shed up to the other edge of the fabric.

The grippers, object of the present invention, penetrate each other when they come together at the shed section and have interacting means capable of interlocking at the beginning of the return run of the grippers to bring about their alignment, to open the feed gripper on the weft thread and close the take-off gripper onto said thread by taking advantage of the opposing pull of the grippers sensibly aligned, one in the prolongation of the other, the force necessary for moving the grippers and to assure the transfer of the weft thread from the one to the other being precisely determined by the pull that the rapiers exert on each other during their return movement. The feed gripper is designated by A and the take-off gripper by B.

The attached drawings, provided as examples, will permit one to better understand the invention, the characteristics it presents, and the advantages which can be obtained from it:

FIG. 1 is a disassembled and perspective view of a gripper A constructed according to the invention.

FIG. 2 is a similar view of a corresponding gripper B, likewise constructed according to the invention.

FIG. 3 is a perspective and disassembled view of a part of gripper A shown in FIG. 1.

FIGS. 4 and 5 are plan views of gripper A in closed and open position respectively, the upper face of the protective body being superposed in horizontal section and removed to permit one to see more clearly the arms of the grippers.

FIGS. 6 and 7 are plan views of gripper B in open and closed position respectively.

FIG. 8 is a perspective view of a closing element of gripper A.

FIG. 9 is a plan view of gripper B in closed position with the jaws of its opening mechanism in the phase preceding their intervention.

FIGS. 10 to 12 show, in views as in FIG. 9, the same gripper B and its opening nechanism in three successive phases of its intervention.

FIGS. 13 to show, in three successive phases, the copenetration and subsequent separation in the course of which the transfer of weft thread from gripper A to gripper B takes place according to the invention.

In a known loom, the opening of gripper A and closing of gripper B at their conjunction is produced by the thrust of the rapiers in their forward motion, whereas on the loom of the invention the same movement of the grippers is controlled by a pull that'the rapiers exert on each other during their return movement.

THE FEED GRIPPER A This gripper contains a protective shield 1 (FIG. 1) to prevent hooking of the warp thread during penetration into the shed. This element has the form of a tube with a rectangular cross section, the vertical lateral sides of which terminate at the front in points 2 and the horizontal sides each likewise have in front a V-shaped groove 3 in which the thread engages. Each vertical lateral side has a window 4 on the front side and a window 5 toward the base on the rear half to permit the opening and closing of the arms of the grippers as will be described below.

The grippers themselves are composed of two similar symmetrical flat arms 9 which can oscillate on a common pin 10 which will be held by screw 11 over hole 6 of the lower horizontal side of the protective shield. The two arms of the grippers on a lug 12 in their center have a borehole 13 through which passes pin 10. The center of said borehole 13 is located exactly in the prolongation of the face of gripping surface 14 which provides the gripping action.

The rear portion of arms 9 of the grippers each form a pallet 15, the exterior side 16 of which is rounded in the form of a cam surface which, when the grippers are placed flat in the bottom of the protective shield, project over the latter and through slot 5 sufficiently to permit one, when the grippers are closed, to open same by exerting, with the fingers, pressure on cam surface 16 of each arm 9 in order to bring them together.

The interior sides 17 of pallets 15 have, on their back part, an upwardly directed spur 18 which acts to keep the grippers open by means of a spring catch described below. They also have an offset 19 formed in pallet 15 which with the back part of side 17 provide lodging for the arms of a closing spring 20 attached to the lower horizontal face of the protective shield by means of a screw 22 and nut 22a through hole 7.

The two front arms 23 of the grippers on their exterior side have a flat vertical tab 24, the upper part of which is folded toward the inside in a horizontal fold 25. This fold is perforated in the forward part by a hole 26 (FIG. 3) located above and perpendicular to a hole 27 made toward the front and on the exterior side in each tip of the grippers. Said two holes 26 and 27 are provided for receiving a vertical pin 28 around which moves a flap 29 moved into position in a plane perpendicular to the vertical clamp 24 by a flexible helical torsion spring 30.

The flap 29 is a small plate which has above and below two right-

angled lugs

33,34 perforated by

holes

35 and 36. In the upper part of the flap there is a folded spur 32. The lower extremity of the spring 30 is inserted into a hole 31 near the base of tab 24 and is fixed in it. The upper end of the spring is slipped under the folded spur 32 of flap 29 and fixed in it. The pin 28 passes longitudinally through spring 30. The two ends of spring 30 are suitably oriented so that, in rest position, flap 29 is positioned in a plane perpendicular to tab 24. This flap can then oscillate about pin 28 in one or the other direction against the action of spring 30 which tends to bring it back into a plane perpendicular to tab 24.

The spring catch 37 (FIG. 1) is U-shaped, the two

vertical portions

38 and 39 of which are pierced by

holes

40 and 41 on the same horizontal axis. The base 42 of said U is flat and has a notch 43 at its front.

Said base 42 on its lower face extending away from notch 43 has a projection 44 having conveniently the shape of a rounded section. The catch 37 is placed inside and toward the back of the protective shield 1; it pivots on pin 47 which passes through

holes

40 and 41 made in the vertical portions of the catch and through holes 45 arranged in the vertical wails of shield 1. Thus, the catch is positioned in such a way that projection 44 lodges in a slot 8 made at the base of shield 1, and extends below same, and in such a way that the base 42 of the catch is slightly above the base of the shield so that the catch can oscillate on its pin 47 without being constrained. A spiral torsion spring 48 surrounds pin 47 and urges the catch toward a position in which the bend of projection 44 attempts to strike against the front end of slot 8. For this, end 49 of spring 48 is introduced into hole 51 made on one vertical wall of the protective shield and is fixed therein, whereas the other end 50 of spring 48 clasps base 42 of the catch and is fixed therein.

Catch 37 being thus positioned, the notch 43 made in its base surrounds the two spurs 18 placed behind the arms of the grippers and keeps the latter in an open position .(FIG. 4).

When a lug G, (FIG. 8) described below, at the beginning of the cycle acts upon projection 44, the catch 37 pivots on its pin 47, its base 42 moves back, notch 43 moves away from the spurs 18 which, released, move away from each other by the action of spring and the gripper closes (FIG. 5).

THE TAKE-OFF GRIPPER B It is comprised (FIG. 2) mainly of a support tube 52 which is shaped like a tube with a very flat rectangular cross-section; it is elongated at its rear by two arms 57 which make it possible to attach it to the rapier of the loom by means of holes 108. The fore part of the tube is open and has a notch 58 on its upper face. In base 59, which closes the tube at its back part, at the front of arms 57 an opening 60 is made, which is smaller than the internal cross-section of the tube.

The rapier head 53 is a flat piece, the main body of which can be introduced and slid into support tube 52. In the forward part of the rapier head the two points 54 are provided which form a V-shaped opening 61 between them where the thread is introduced, and each of the two said points has a hook on the outside of the V. This rapier head 53 is extended at the back by a narrow tongue 63 which can enter and slide in the opening 60 arranged in the base 59 of the tube 52. Said tongue is pierced at the end by a hole 64 for receiving a pin 65. Two

holes

66 and 67 are likewise made in the rapier head body on the longitudinal axis thereof at suitable locations.

The arms 55 of gripper B are two hoop irons resembling the arms of chisels and are symmetrical, but each is located entirely on its respective side of a common pm.

Toward the middle of each arm a lobe 72 is pierced by a hole 73 which allows the two arms to receive a common pin 71. The extension of the inside edge 74, by which the arms 55 come into contact with each other when the gripper is closed, passes through the axis of the common pin 71. The rear part of the arms of the gripper forms a pallet 79, the exterior side of which in outline forms a rounded boss 80 large enough so that it passes laterally beyond the rapier head even when the gripper is open.

At their rear extremeites these arms 55 end in spurs 81 capable, when the gripper is open, of fitting together in notch 58 of support tube 52 which then keeps the gripper open.

The two arms are mounted on the rapier head 53 by common pin 71 fixed in hole 66. When the gripper is open, these two arms do not extend beyond the breadth of the rapier head (except for their bosses 80) so that the hooks of the rapier head project over the breadth of the rapier head and the two arms of the gripper. The closing spring 68 is attached tothe rapier head by screw 69 inserted into hole 67. This spring is kept above the arms 55 of the gripper B without impeding their action by an expanding ring 84 which is as thick as the two arms of the gripper when superposed. The ends of closing spring 68 are slid under tongues 78 arranged between two slits on the interior sides of the arms of the gripper so as to urge the latter toward its closed position. The rapier head thus equipped is introduced into the support tube 52 where the rear end of its main body can slide into contact with base 59 of the tube against which it will rest.

The small tongue 63 of the rapier head crosses opening arranged in the base 59 of the tube 52 and extends between the two arms 57. A spiral compression spring 56 is slid over said tongue 63 and is covered by sleeve 82. A washer 83 is slipped onto the end of tongue 63 to compress spring 56 and is kept in this position by a pin inserted into hole 64. It is to be understood that by the action of the return spring 56 when the gripper is open (FIG. 6) the two spurs 81, which are consequently drawn together, are engaged in notch 58 of the support and that the gripper thus remains in an open position against the action of the closing spring 68.

On the other hand, if it is drawn over the rapier head 53 against the action of return spring 56, it will slide into the support tube 52. Under the action of the closing spring 68, the rear parts of the arms of the gripper, released from the impediment of notch 58, open up and the gripper closes (FIG. 7). The sleeve 82, which covers the return spring 56, is of a suitable length so that the advance of the rapier head into the support tube 52 is sufficient to release spurs 81 from notch 58 but not needlessly greater.

DRIVE STOP (G) CLOSING THE FEED GRIPPER A It is located on the side of the loom where the rapier of gripper A is, apart from the shed, at a place convenient so that its action on projection 44 of catch 37 closes gripper A on the end of the weft thread at the exact location that said thread is presented to the gripper by the usual selection devices.

The stop G has theform of a half-segment 85 (FIG. 8), the arc of the circle of which is turned upward, the horizontal cord downward, and the rise is vertical. Said half-segment 85 is located at the end of a thin elastic plate 86 attached at its other end to a fixed point 87. It is to be understood that when gripper A advances, the stop G will press back projection 44 and with it catch 37, which will make the gripper close, whereas, when the gripper returns at the end of the cycle, projection 44 of the catch coming against the end of the slot 8 will flex spring 86 and the stop will not affect catch 37.

REOPENING MECHANISM OF TAKE-OFF GRIPPER B In order that the weft thread, after having been drawn across the shed, is then to be released by gripper B, a mechanism for reopening the gripper is provided, which can be located at a convenient point beyond the material on the path of said gripper so as to reset itin the opening position and to feed the end of the weft thread to it exactly at the outlet point of the shed.

This mechanism is comprised mainly of two horizontal segments of circle 89 (FIG. 9 to 12) from 45 to 60 forming two kinds of jaws pivoting on two vertical pins 90. These two segments 89 are located in regard to each other at a distance such that when they describe a movement of partial symmetric rotation they leave between them a space sufficiently small so that the bosses 80 of gripper B come into contact with segments 89 and make the gripper open. The linear velocity of the arcs of segments 89 in their rotation should be slightly higher than the displacement velocity of the rapier in order to fascilitate the engaging of spurs 81 in notch 58 of the support tube, the engaging of which is aided by the action of spring 56. Synchronization of the movement of the two segments 89 can be assured by two cogged segments, respectively integral with segments 89, geared one against the other and moved by any known means, for example, by the action of a lever, the end of which should rest on a cam suitably located on a rotating shaft of the loom.

OPERATION It is acknowledged that the gripper A starts on the right where the thread supply is located and that gripper B starts on the left.

The grippers begin to advance. Gripper A begins in open position on the right (FIG. 4), it encounters the thread presented by an eyelet at the moment the stop G comes into contact with projection 44 of catch 37 which moves back, the gripper closes on the thread (FIG. 5) and pulls it across the shed. Simultaneously, gripper B starts in open position on the left.

The jaws 89 are turned aside from the fabric and allow it free passage to gripper B and the rapier. Gripper B, now open, penetrates the shed. Having arrived at the center of the fabric, the two grippers come together at a variable depth, gripper A always holds the thread, gripper B is always open.

The rapiers begin to start the grippers back and before their separation, gripper B, upon closing, opens gripper A and the thread is transferred.

Details of the mechanism for making this transfer will be given below. The grippers withdraw from the shed; gripper A is open and empty, gripper B is closed and carries the weft thread along to the second half of the widith of fabric. When gripper A proceeds to the right of the shed, it meets stop G, projection 44 of the catch deflexes the spring plate 86, so that the stop is ineffective, and the gripper arrives at its initial open position.

Simultaneously, gripper B, closed, moves to the left of the shed under the effect of the cam placed on the rotation shaft of the loom having carried along the weft thread. Segments 89 of the opening mechanism pivot One will recall from the very first that gripper A arrives in a closed state with the weft thread clamped between its tips, while gripper B arrives on its side in an open state. The thread should be introduced between the tips of gripper B and the latter should close while gripper A simultaneously remains open.

FIG. 13 shows the two grippers at the moment they penetrate each other. It can be seen that the rapier head 53 and gripper B are narrow enough to easily penetrate the protective shield l of gripper A even if they do not appear exactly in the center line of said shield in order to open toward the right the flaps 29 against their return springs 30 which offer but negligible resistance.

The mutual penetration can be continued simply (FIG. 14) until the bases of the V-shaped openings of the two grippers are superposed, which represents substantial travel tolerance. When the grippers begin to move back, they do not undergo any action until the hooks 62 of the rapier head of gripper B encounter the flaps 29 which strike and slide against the lateral sides of the rapier head. At this moment (FIG. 15) hooks 62 cause the flaps 29 to move back to the left to allow passage. Upon moving back, said flaps, while being supported on their pins 28, spread apart the tips of gripper A which opens, the spurs l8 engaging notch 43 of the catch; gripper A remains open, the thread is released. But simultaneously, hooks 62 encounter, from flaps 29, a slight resistance by traction, sufficient never-the-less to slide the rapier head 53 into its support 52 against the action of return spring 56. Spurs 81 of the arms of gripper B are disengaged from notch 58 of the support; gripper B closes again by the action of spring 68 and grips the weft thread at the same time that it is released by gripper A.

Thus, the invention makes it possible to establish a system of grippers for shuttleless looms with two needles or rapiers, the tension of which is by positive action, therefore capable of gripping and pulling threads of completely different sizes and types without preliminary adjustment, and the good operation of which does not require dimensional precision either in coming together or in mutual penetration.

I claim:

1. In a loom on which the insertion of weft threads into successive sheds is accomplished by two gripper rapiers, a feed gripper A and a take-off gripper B which, starting from opposite sides, meet in the middle of a shed where the feed gripper A transmits to the take-off gripper B, a weft thread which it has drawn from a fixed supply located on one side of theloom, and characterized in that the grippers penetrate each other when they meet in the middle of the shed; each gripper being provided with a cooperating means (29 62) which while said grippers are in the prolongation of each other act to mutually interlock at the beginning of the return run of said grippers so as to ensure the alignment thereof; to open gripper A to release the weft thread, and to close gripper B on to the same weft thread, said actions being brought about by the opposite pull of said grippers.

2. A loom as in claim 1, wherein gripper A includes a pair of pivoted arms (9) having front portions (23), pins (28) each mounted on one of the portions (23) pivotally mount flaps 29 perpendicular to the clearance plane of the arms springs (30) carried by pins (29) act to maintain said flaps in position to provide a pivotal gate (23) on the lateral faces of the gripper A said gate being in the path of take-off of gripper B and capable of allowing free forward passage and free outward passage to at least the part before the tip of the gripper B, said tip comprising means (54, 62) capable of moving apart said flaps (29) on'their forward run and of engaging said flaps on the return run so as to act against pins (28) and thereby force open the tip of gripper A against the pressure of closing spring (20); the resistance of said encounter exerting a force on gripper B which brings about the closing of its gripper member.

3. A loom as in claim 1, characterized in that the gripper A is provided, adjacent to the inward ends of arm (9), with a pin (47) mounted perpendicular to the axis of pin (10), catch (37), which has notch (43) formed therein, is pivotally mounted on pin (47) and urged into an operative position by spring (48), said catch (37) extends outward of the contour of the gripper, a stop (G) is positioned along the path of the gripper in position to engage said catch at the beginning of the forward run of said gripper which engagement causes notch (43) to release spurs (l8) and allows the gripper to close on the weft thread.

4. In a loom on which the insertion of weft threads into successive sheds is performed by two rapiers, a feed rapier having a gripper A and a take-off rapier having a gripper B, which starting from opposite loom sides meet in the middle of a shed where the feed gripper A transfers to the take-off gripper B, a weft thread which it has pulled from a fixed supply located on one side of the loom; and characterized in that the gripper (A, B) of at least one of the rapiers comprises pivoting arms (9,55), said arms comprising front portions (23,25) located adjacent for forward portion of said rapiers, spring (20,68) mounted about the pivotal axis of said arms act to urge said front portions together, rear portions (18,81) of said arms (9,55) cooperate with notch (43,48) formed integral with a mobile drive element (37,52) carried by said gripper A,B, said element (37,52) functioning to release the gripper arms to said gripping position or to keep the front portions of said arms separated.

S. A loom as in claim 2, characterized in that the means (62) of gripper B comprises at least a pair of harpoon-like hooks which extend beyond the opposite lateral sides of said gripper when open.

6. A loom as in claim 5, characterized in that gripper B carries a plate 53 which has one end formed as parallel extensions the ends of which comprise hooks (62), plate (53) is provided with a pin ,(71) which pivotally mounts a gripping element and a closing spring (68), spring (68) acts against tongues (78) of said gripping element to urge arms (55) into mutual contact; said extensions are shaped in the form of a V having an angle which coincides approximately with that of arms (55) when in the open position.

7. A loom as in claim 6, characterized in that gripper B includes a support tube (52) in which plate (53) is slidably mounted, said tube (52) is formed with a notch (58) which acts to receive and retain opposite ends (81) of gripper arms (55) so as to retain same in the open position, spring (56), integral with tube (52), is engaged with plate (53) so as to urge same inwardly of said tube to a position in which ends (81) of arms 55) are received in notch (58) and retained in an open position, plate (53) is urged toward the outside of tube (52) during initial outward movement of grippers A,B which movement releases ends (81).

8. A loom as in claim 7, characterized in that the arms 55 have formed at their opposite ends control bosses (80) which protrude from opposite sides of the gripper B, a pair of jaws 89 are mounted adjacent to the extreme withdrawn position of said grippers and in the path of bosses (80) so that when said grippers move to said withdrawn position said jaws act on said bosses to urge against spring 68 and move end portions (81) into position to be engaged by notch (58).

Claims

1. In a loom on which the insertion of weft threads into successive sheds is accomplished by two gripper rapiers, a feed gripper A and a take-off gripper B which, starting from opposite sides, meet in the middle of a shed where the feed gripper A transmits to the take-off gripper B, a weft thread which it has drawn from a fixed supply located on one side of the loom, and characterized in that the grippers penetrate each other when they meet in the middle of the shed; each gripper being provided with a cooperating means (29, 62) which while said grippers are in the prolongation of each other act to mutually interlock at the beginning of the return run of said grippers so as to ensure the alignment thereof; to open gripper A to release the weft thread, and to close gripper B on to the same weft thread, said actions being brought about by the opposite pull of said grippers.

2. A loom as in claim 1, wherein gripper A includes a pair of pivoted arms (9) having front portions (23), pins (28) each mounted on one of the portions (23) pivotally mount flaps 29 perpendicular to the clearance plane of the arms springs (30) carried by pins (29) act to maintain said flaps in position to provide a pivotal gate (23) on the lateral faces of the gripper A said gate being in the path of take-off of gripper B and capable of allowing free forward passage and free outward passage to at least the part before the tip of the gripper B, said tip comprising means (54, 62) capable of moving apart said flaps (29) on their forward run and of engaging said flaps on the return run so as to act against pins (28) and thereby force open the tip of gripper A against the pressure of closing spring (20); the resistance of said encounter exerting a force on gripper B which brings about the closing of its gripper member.

3. A loom as in claim 1, characterized in that the gripper A is provided, adjacent to the inward ends of arm (9), with a pin (47) mounted perpendicular to the axis of pin (10), catch (37), which has notch (43) formed therein, is pivotally mounted on pin (47) and urged into an operative position by spring (48), said catch (37) extends outward of the contour of the gripper, a stop (G) is positioned along the path of the gripper in position to engage said catch at the beginning of the forward run of said gripper which engagement causes notch (43) to release spurs (18) and allows the gripper to close on the weft thread.

4. In a loom on which the insertion of weft threads into successive sheds is performed by two rapiers, a feed rapier having a gripper A and a take-off rapier having a gripper B, which starting from opposite loom sides meet in the middle of a shed where the feed gripper A transfers to the take-off gripper B, a weft thread which it has pulled from a fixed supply located on one side of the loom; and characterized in that the gripper (A, B) of at least one of the rapiers comprises pivoting arms (9, 55), said arms comprising front portions (23,25) located adjacent for forward portion of said rapiers, spring (20,68) mounted about the pivotal axis of said arms act to urge said front portions together, rear portions (18,81) of said arms (9,55) cooperate with notch (43,48) formed integral with a mobile drive element (37,52) carried by said gripper A,B, said element (37,52) functioning to release the gripper arms to said gripping position or to keep the front portions of said arms separated.

5. A loom as in claim 2, characterized in that the means (62) of gripper B comprises at least a pair of harpoon-like hooks which extend beyond the opposite lateral sides of said gripper when open.

6. A loom as in claim 5, characterized in that gripper B carries a plate 53 which has one end formed As parallel extensions the ends of which comprise hooks (62), plate (53) is provided with a pin (71) which pivotally mounts a gripping element and a closing spring (68), spring (68) acts against tongues (78) of said gripping element to urge arms (55) into mutual contact; said extensions are shaped in the form of a V having an angle which coincides approximately with that of arms (55) when in the open position.

7. A loom as in claim 6, characterized in that gripper B includes a support tube (52) in which plate (53) is slidably mounted, said tube (52) is formed with a notch (58) which acts to receive and retain opposite ends (81) of gripper arms (55) so as to retain same in the open position, spring (56), integral with tube (52), is engaged with plate (53) so as to urge same inwardly of said tube to a position in which ends (81) of arms (55) are received in notch (58) and retained in an open position, plate (53) is urged toward the outside of tube (52) during initial outward movement of grippers A,B which movement releases ends (81).