US3807459A

US3807459A - Axminster gripper

Info

Publication number: US3807459A
Application number: US00204930A
Authority: US
Inventors: R Tolley
Original assignee: CROSSLEY J AND SONS Ltd
Current assignee: CROSSLEY J AND SONS Ltd
Priority date: 1971-12-06
Filing date: 1971-12-06
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30

Abstract

A gripper type Axminster carpet loom in which the grippers are so shaped in substantially U-form as to lie always on one and the same side of the path of the weft insertion needle, whereby the weft insertion needle and the grippers can utilize the full loom cycle to perform their respective functions without having to wait for each other to clear the warps.

Description

AXMINSTER GRIPPER Inventor: Ronald Ferick Tolley, Dewsbury,

England Assignee: John Erossley & Sons Limited,

Halifax, Yorkshire, England Filed: Dec. 6, 1971 7 Appl. No.: 204,930

References Cited UNITED STATES PATENTS 10/1931 Alvord 139/7 D Apr. 30, 1974 3,521,676 7/1970 Maclsaac et a1 139/7 D FQREIGN PATENTS OR APPLICATIONS 1,433,015 4/1965 France 139/7 D 416,673 9/1934 Great Britain t. 139/7 D Primary Examiner-Henry S. Jaudon Attorney, Agent, or FirmMelvin A. Crosby 57 TRACT A gripper type Axminster carpet loom in which the grippers are so shaped in substantially U-form as to lie always on one and the same side of the path of the weft insertion needle, whereby the Weft insertion needle and the grippers can utilize the full loom cycle to perform their respective functions without having to wait for each other to clear the warps.

2 Claims, 7 Drawing Figures sleevlws PATENTEUAPR 30 I974 sum 2- ur a I AXMINSTER GRIPPER This invention relates to gripper Axminster carpet looms.

The principal object of the present invention is to increase the speed of operation of a spool-gripper Axminster loom.

Accordingly, the present invention consists in a gripper Axminster loom which includes a plurality of parallel spaced grippers each of which has relatively movable parts and each of which is mounted upon a shaft which is both common to all of said grippers and located above chain warps which are movable relative to one another to form warp sheds, eachgripper further being so shaped that said gripper does not at any time intersect the path of travel of a weft-insertion needle during movement of said gripper by said shaft from the position thereof at which the pile yarn is gripped thereby to the position thereof at which a severed pile tuft is laid against the fell of the cloth, and vice versa, whereby each of the weft-insertion needle and the gripper is enabled to utilize three-quarters of the full loom cycle without having to be held back whilst the other is moved clear of said chain warps.

The grippers, although mounted on said shaft which extends across the loom above said chain warps, are such that a part of each of them remains in the warp and in the reed of the loom, and this gives rise to the further advantage that there is not any possibility of the warp ends being split when said grippers present the pile tufts to the fell of the cloth.

BRIEF DESCRIPTION OF THE INVENTION A number of very important advantages, which are not immediately apparent, accrue from the, construction and mode of operation of a loom constructed according to the present invention.

A general remark will not be out of place before particular features'are selected for comment. If the known looms which are operable to produce gripper Axminster carpets (see for example those described in the book entitled Carpets by George Robinson published by Sir Isaac Pitman and Sons Limited) are operated at the very highest speeds compatible with the production of saleable carpet, a great deal of wear and tear is caused in the loom by vibration, by parts contacting end stops with a force which is a-function of the speed of operation and so on. Furthermore, once one has reached the operational speed limits for such looms, it is only possible to obtain a further increase in yardage of cloth produced by those looms by redesigning a certain part or parts of the looms and/or by producing what may be called an intermediate product which can be produced at a greater speed than that at which a complete carpet can be produced, the term intermediate" being intended to refer to a carpet body or top which is not saleable in the form in which it is taken off the loom but which needs to be rendered saleable by the application thereto of a good quality durable backing to the underside thereof.

Consequently, it has been one of the principal aims of this invention to design a gripper Axminster loom whose mode of operation is such that vibration, whilst obviously not eliminated, is minimized and which is capable of inserting a greater number of tuft rows per minute for any given width of loom than a known loom of corresponding width is capable of inserting. By a complete carpet is meant a carpet which has a backing but which has, in common with all woven carpets, to undergo several finishing treatments, namely, brushing, light shearing or cropping, mending or picking, sizing, steaming and so on.

I. In known gripper Axminster looms, the weft insertion needle can only perform its function whilst the grippers are out of the path of travel of that needle and the consequence of this is that the grippers carrying the severed tuft lengths of yarn must. be operated to lay the free ends of those tuft lengths against the fell of the cloth before the needle can be moved across the loom because the path of movement of the grippers during tuft-insertion crosses the path of movement of the weft-insertion needle. In these known looms, therefore, the needle must in practice be moved at high speed in one direction, must be stopped and must then be moved back .again to its starting position at high speed.

By contrast, in the loom according to the present invention, the weft-insertion needle has a time cycle of substantially 270 because the path of movement of the grippers during their yarn-gripping and tuft-insertion movements does not cross that of the weft-insertion needle.

Consequently, the grippers and the needle can be performing their respective functions simultaneously, and this means that the speed at which the needle is moved to and fro across the loom is no longer critical insofar as the grippers are concerned and is much slower than is the case in known looms. The principal factor determining the speed of the weft-insertion needle is the necessity for the needle to be clear of the warp sheds by the time the reed starts to beat-up.

2. It will be obvious that what has been said in 1 applies, mutatis mutandis, to the grippers in known looms because those grippers must also be moved at as high a speed as possible from one position thereof to the or each other position thereof because the weft-insertion needle cannot insert the'double shots of weft at the same time as the grippers move upwardly or downwardly across the path of movement of the needle.

By contrast, in the loom according to the present invention, the weft-insertion needle and the grippers are operable simultaneously to perform their respective functions, the grippers being moved more slowly than is the case in known looms.

3. In known gripper Axminster looms employed as one-shot looms, the grippers carry the severed tuft lengths downwardly and lay the free ends of those tuft lengths against the fell of the cloth. Thereafter, the weft-insertion needle inserts the double shot of weft by travelling across the loom to the selvedge shuttle, coming to rest at that location and then travelling back again. Only when the needle has cleared the warp shed during its return travel can the grippers be actuated again to move upwardly to the proffered yarn ends, to grip those ends, to draw off the required tuft lengths, to wait whilst the required tuft lengths are severed and then to move downwardly to effect tuft-insertion. A typical figure, expressed in degrees as before, for these operations is 169 /2 of which the cycle time to rise from the fell of the cloth to the spool frame or yarn carrier is 51 draw-off time is 20 cutting time is 48 and tuft-insertion time is 50 /2..

By contrast, in the loom according to the present invention, the total cycle time for effecting the corresponding operations is 275, of which 85, is allotted to the lifting of the grippers from the fell of the cloth to the devices which hold the yarn ends, 55 is allotted to draw-off of the required lengths, almost 60 is allotted to the cutting time and 75 is allotted to tuft-insertion. It will be noted that the cycle time of substantially 60 for cutting represents an increase of 8 percent which is important because this enables a more gradual operation of the cutters which cut off the yarn which have to be displaced initially in one direction, and finally in the opposite direction in order to restore them to their rest position. These more gradual or less hurried movements of the cutters further reduce vibration and wear and tear on the loom.

4. Beat-up time with the loom according to the present invention is ample, in spite of the fact that the speed of movement of the weft-insertion needle is much slower than is the case in known looms. In fact the cycle time for the weft insertion needle can be well over 90 and this means that the reed is not moved at such a speed forwardly or backwardly as will give rise to an objectionable degree of vibration.

5. Production speed of the intermediate product consisting, for example, of a cloth 27 inches wide with 7 rows per inch has been 50 tuft rows inserted per minute. This compares with, say, 25 tuft rows inserted per minute of the completed carpet 27 inches wide with 7 rows per inch. Although the greatly increased footage is only of the intermediate" product and not ofa complete carpet, nevertheless it is consdered that it will be possible to obtain, with ease, an overall increase in production of complete carpet per unit time over that obtained from the known gripper Axminster looms because many types of good quality backing are known together with proven methods of application thereof.

6. The use of the two cams, together with the provisions of an adjustable stop member facilitates speedy regulation of the pile height as and when desired.

7. The fact that the grippers of the loom are in permanent engagement with the reed of the loom eliminates the usual critical timing sequence between the breast comb, the reed, and the said grippers. Owing to the fact that parts of the grippers are always in the warp, even when at the yarn-gripping positions thereof, there can be no possibility of the warp ends becoming split by grippers as they move downwardly in an arc to present the severed tufts to the fell of the cloth.

The present invention will now be more particularly described with reference to the accompanying drawings, in which:

FIG. 1 illustrates, partially in said elevation and partially in cross-section, one embodiment of a gripper mechanism of a gripper Axminster carpet loom constructed in accordance with the present invention, said gripper mechanism being in the yarn gripping position thereof and about to be actuated to grip the pile yarn tufts. A

FIG. 2 illustrates, also partially in side elevation and partially in cross-section, the gripper mechanism of FIG. 1 in the tuft-insertion position thereof and about to be actuated to release the respective ends of the inserted tufts.

FIG. 3 illustrates in front elevation a detail view of part of the gripper mechanism.

FIG. 4 illustrates diagrammatically in side elevation the operating means by which the grippers are actuated to perform their functions simultaneously.

FIG. 5 illustrates diagrammatically in front elevation the operating means shown in FIG. 4 and a part of the main drive.

FIG. 6 illustrates various elements which together comprise the gripper mechanism.

FIG. 7 is a circular timing chart in which the shaded portions of the concentric bands relating to the various parts of the loom with which the chart is concerned indicate translational movement of those parts and in which the unshaded portions of said bands indicate when those parts are stationary.

DETAILED DESCRIPTION OF THE INVENTION:

Referring to the drawings, a standard spool-gripper Axminster loom modified in accordance with the present invention includes a main frame (not illustrated) in which two

parallel shafts

10, 11 are mounted, the shaft being the main drive shaft and carrying a spur gear 12 which meshes with a spur gear 13 keyed to the shaft 11.

Secured to or integral with the shaft 11 is a cam 14 connected to the shaft 11, a cam follower 15 being in contact with the periphery of the cam 14 and being carried by a lever 16 which is mounted for small angular movements upwardly and downwardly about the axis of a rod 17 in responseto rotation of the shaft 11 and of the cam 14. Also secured to or integral with the shaft 11 is a cam against whose periphery there bears a cam follower 26 which is carried by a lever 27 which is also mounted for small angular movements upwardly and downwardly about the axis of the rod 17 in response to rotation of the shaft 11 and of the cam 25. The lever 16 carries an adjustable stop member 28 which (as can be seen in FIG. 4) is in register with the free end of the lever 27 and is vertically above said free end. The purpose of the stop member 28 will be described in due course.

That end of the lever 16 which is adjacent the stop member 28 is pivotally connected to one end ofa link 30 whose other end is pivotally connected to a radial arm 31 which is formed with a closed slot 32 for the purpose of adjustment of the point of the pivotal attachment of said other end of the link 30 to said radial arm. Said radial arm 31 is integral with a collar 33 which is keyed to a tubular shaft 35 which is suspended in bearings 36 in the main frame of the loom. A fret 37 is attached to the shaft 35 (for example by screws which are not illustrated) so as to depend from the underside thereof as seen in FIGS. 1 and 2.

Concentrically disposed within the shaft 35 is another shaft 38 which is connected to means operable at predetermined spaced times during the loom operating cycle to cause said shaft 38 to move angularly about its longitudinal axis relative to the shaft 35, firstly in one direction and secondly in the opposite direction, a number of C-type bearings 40 being located in circumferential grooves therefor which are formed in said shaft 38 and which are spaced apart along the axis of the shaft 38 in order to reduce the friction between the relatively angularly movable shafts and to maintain exact centering of the shaft 38 within the shaft 35. Bearings 40 are advantageously disposed axially between adjacent grippers along

shafts

35 and 38.

The shaft 38 has a slot 41 machined therein which extends from one end of the shaft to the other and which (in section radially of the shaft) has a shape identical with that of the profile of an involute gear tooth. Similarly, the shaft has slots 42 cut therein at regular intervals (namely, spaced 9 inches apart from one another), said slots 42 being in register (radially of the shafts 35, 38) with the slot 41 in the shaft 38, the

slots

42, 42 and the relative positioning thereof being for a purpose which will be described hereinafter.

For the sake of simplicity, the construction of only one gripper and the manner in which only one gripper is mounted will now be described. A gripper 45 consists of two pivotally connected

parts

46, 47. The part 46 is provided with a tang 48 at one end thereof and with a jaw member 49 at the other end thereof and the part 47 is bifurcated at the end 50 thereof and is provided with a jaw member 51 at the other end thereof, the jaw members 49, 51 being such as to coact with one another to grip a pile yarn end or pile tuft when the grippers is appropriately actuated. The tang 48 is inserted into the relevant slot 52 in the fret 37 and retaining pieces 55 are secured to the body of the fret in order to prevent accidental detachment of the gripper from the fret.

The fret 37 is also formed with a slot 56 in which a slide 57 is accommodated with the interposition of a bronze seating 61. The slide has a tooth 58 whose profile is complementary to the cross-sectional shape of the slot 41 and also has a block 59 at one end thereof which is machined to provide spaced shaped slots 60. When assembled in its working location, the tooth 58 of each slide 57, projects through the relevant slot 42 into the slot 41 in the shaft 38 and the slotted block 59 engages the bifurcations 50 of the parts 47 of the grippers with which the particular slide is associated, each slide 57 having freedom for sliding movement in the slot 56 and being moved in that slot 56 under the control of the shaft 38 eitherto bring the jaw members 49, 51 together to grip a pile yarn end or pile tuft or to move the jaw members 49, 51 apart to release said end or tuft.

A reed indicated generally by the reference numeral includes, as in one conventional form thereof, a plurality of spaced metal strips 66, said reed being movably by conventional mechanism (not illustrated) from the position thereof which is illustrated in FIG. 1 to the position thereof which is illustrated in FIG. 2 and back again. One of the metal strips 66 is disposed at all times between the same two pairs of chain warps 67, 68; the warps in each pair being controlled by healds which are indicated generally by the reference numeral 69 and which will not be further described because the purpose and manner of operation are wellknown and are not the subject of the present invention.

The pile yarns which are to be woven into a body or top are supplied from spools 70 of which one is illustrated in FIG. 1 at the draw-off position. The spools 70 are carried in a heavy-duty link-type conveyor chain of which the outer link plates have attached thereto substantially T-shaped lugs 76 (for example by welding), said lugs having holes near the ends thereof to receive retaining pins of spool frames 81, the chain 75 being driven by means of a driven shaft 77 to which there are secured sprocket wheels 78 (only one visible in the drawings). The drive is intermittent because each spool must be brought to and must be allowed to dwell at the draw-off position for a period of time sufficient to permit the desired amounts of pile yarn ends or tufts to be drawn off and severed. The yarn 79 is threaded through a holding device 80 which forms a part of the relevant spool frame 81 and by which it is so held that, along the length of each spool, all the yarn ends or tufts are appropriately proffered to the grippers.

Associated with each spool frame 81 at intervals along the length thereof is a number of brackets 85 whose free ends are engaged by V-shaped notches 86 formed in the ends of an equal number of levers 87, pivotally supported at 87a, whilst the grippers 45 are being raised towards the position thereof illustrated in FIG. 1 by the rotation of the shaft 11, the lifting of the lever 16 and the anticlockwise angular movement (as seen in FIG. 4) of the radial arm 31, said angular movement of the radial arm 31 causing identical angular movement of the shaft 35 which carries cams 88 which engage cam followers 89 carried by the levers 87. The engagement of the free ends of said brackets 85 by the V-shaped notches 86 steadies the spool frame and ensures not only that all of said brackets 85 are in alignment with one another but also that all of the yarn ends or tufts are in alignment with one another.

The loom is provided with sliding cutters indicated generally by the reference numeral 90 whose mode of operation is well-known to those in the art and which are operable to cut the yarns 79 when the requisite lengths have been drawn off by the grippers.

Lastly, there are illustrated in the drawings a weftinsertion needle 95, a rake 96 and a breast comb 97. The welft-insertion needle is a conventional part of an weft-insertion Axminster loom and many other kinds of loom, and is moved with reciprocating motion across the loom inserting double shots of weft which are prevented from slipping back (when the needle is withdrawn) by a strong thread which is fed from a known selvedge shuttle (not illustrated) through the loop of the double shot, thereby also forming a firm and straight selvedge. The rake 96 is a conventional part of an Axminster loom which is positioned, when idle, as illustrated in FIG. 1, namely, in front of the fell of the cloth being made. The function of the rake 96, which the rake is made to perform by appropriate known operation mechanism, is to draw the tufts last-inserted into positions in which they will not either interfere with or be interfered with by the yarn ends or tufts which will be brought down by the grippers for insertion into the cloth being woven. Likewise, the breast comb 97 is a conventional part of many looms and is the table on which the work is made and from which it could be, for example, intermittently drawn up by a take-up roller.

The operation of the loom whose principal parts, as affected by the present invention, have been described above is as follows:

It will be assumed that the spool chain 75 has been moved to bring to the draw-off position that spool frame 81 which contains the yarn ends or tufts which are to form the next row of tufts in the carpet being woven. Substantially at the instant when the spool chain movement ceases, the grippers 45 have been opened to release the yarn ends or tufts just inserted and are on the point of being moved upwardly to the yarn-gripping positions thereof by appropriate angular movement of the shaft 35 (namely, in an anti-clockwise direction of angular movement as seen in FIGS. 1 and 2). Again, at the instant when the spool chain movement ceases, the reed 65 is about to be moved away from the fell of the cloth having completed its beatingup operation, the healds 69 are being operated to form the warp sheds for the next weft-insertion and the welfinsertion needle 95 has begun its traversing movement towards a side shuttle (not illustrated) which is also called a selvedge shuttle and whose construction and mode of operation are well-known in the art.

The shaft 35 moves angularly in said anti-clockwise direction thereby (a) lifing the grippers 45 to the positions thereof illustrated in FIG. 1, and (b) causing the coacting cams 88 and cam followers 89 to raise the levers 87 to an extent such tht the V-shaped notches 86 thereof engage the brackets 85 of the spool frame 81. During this movement of the grippers, the leading end of the weft-insertion needle 95 will have moved to a point approximately one third of the way across the warp sheds and the healds 69 will have completed their relative movement to form those warp sheds. Furthermore, the reed 65 will have finished beating-up at substantially the same time as that at which the healds 69 come to rest, said reed having returned to the position thereof illustrated in FIG. 1.

It is also to be noted that, as the opened grippers move upwardly, the tip of the jaw member 49 of the part 46 of each gripper pushes the previously gripped yarn end or tuft portion into an upright position which is thereafter maintained by the rake 96 which has been moved from the FIG. 2 position thereof to the position thereof illustrated in FIG. 1.

The shaft 38 is now moved angularly in an anticlockwise direction (as seen in FIG. 1) relative to the shaft 35 in order to close the jaw members 49, 51 of the several grippers to grip the yarn ends or tufts, said jawclosing being effected by the engagement of the teeth 58 of the slides 57 in the slot 41 and by the engagement of the bifurcations 50 by the blocks 59 and the consequent sliding of said slides towards the right (as seen in FIG. I).

The shaft 35 is now moved angularly in a clockwise direction to cause the grippers to draw off the required tuft lengths of yarn and is then stopped by the stop member 28 making contact with the lever 27.

The cutters 90 are then moved into the position in which the tuft lengths can be severed, are operated to sever the tuft lengths and are thereafter retracted. By the time the required tuft lengths have been drawn off by the grippers, the weft-insertion needle 95 will have completed its traverse of the warp sheds and will have come to rest having brought the weft to the side shuttle which will be operating to bind the weft shots at that edge of the work by a strong thread which will prevent the weft from slipping back when the needle 95 is withdrawn and which will thus form a firm, straight selvedge.

The angular movement of the shaft 35 to draw off the required tuft lengths is not sufficient to cause the notches 86 to be moved away from the brackets 85, the engagement of the brackets 85 by said notches being maintained during tuft cutting.

After a dwell long enough to permit the selvedge shuttle to perform its function, the weft-insertion needle 95 begins its reverse traverse of the warp sheds and, during approximately one-half of the time taken by the needle 95 to become fully withdrawn, the cutters are being moved and operated in the manner already described to sever the drawn-off tuft lengths. After tuft cutting, further angular movement of the shaft 35 permits disengagement by the notches 86 of the brackets and subsequent indexed movement of the spool chain 75.

Upon completion of tuft severence, tuft insertion and spool chain movement are started simultaneously. Thus, the grippers 45 holding the severed tuft lengths are caused to continue their downwards movements in order to lay the free ends of those tufts against the fell of the cloth. At this time the needle will have completed its withdrawal from the warp sheds and consequently the reed 65 is moved from the FIG. 1 position thereof to the FIG. 2 position thereof in order to position the double shot of weft on the tufts approximately at the mid-length points as indicated by the reference numeral in FIG. 2. In addition, just after the reed 65 has started to move to the right as seen in FIG. 1, the healds 69 are moved relative to one another in order to form the warp sheds for the next weft-insertion and thus incidentally to assist in the binding of the inserted double shots of weft in their eventual beaten-up positions in the cloth.

As the reed reaches the extreme point of beat-up, the

jaw members 49, 51 are opened by angular movement of the shaft 38 relative to the shaft 35.

The weaving cycle is complete.

Modifications may be made within the scope of the appended claims.

I claim:

1. A spool-gripper Axminster loom which comprises a frame; a rotatable tubular first shaft in said frame and a solid rotatable second shaft arranged concentrically within said first shaft, yarn grippers spaced along a line parallel to said shafts; a weft-insertion needle moveable along a path which is parallel to said shafts and adjacent said yarn grippers, means including heald means operable to form warp sheds; a spool conveyor chain in said frame; spool frames carried by said spool conveyor chain and protruding therefrom and moveable in succe'ssion into working position within the range of said yarn grippers; spaced engagement fingers on each spool frame; spaced lever means pivotally supported at their one ends in said frame and at their other ends having notch means for engagement by the said engaging fingers of the respective spool frame which is in working position, means for actuating said lever means about the pivotal supports thereof on said frame toward and away from finger engaging position; each gripper having two arm parts and each arm part having two ends, said arm parts being pivotally connected to one another at locations intermediate said ends, corresponding one ends of the two arm parts being formed as complementary jaw members, the other end of one of the two arm parts being fixedly secured to said first shaft and the other end of the other of the two arm parts being operatively connected to said second shaft for opening and closing of said complementary jaw members in response to relative rotation of said first and second shafts; said first and second shafts being angularly moveable in unison about the common axis of rotation of said shafts to displace the grippers bodily between first positions thereof in said frame in which yarn ends presented by a spool frame which has been positioned in working position by said conveyor chain can be gripped thereby and second positions in said frame in which yarns gripped by said grippers are laid against the fell of the cloth, means to cut off each yarn between a yarn spool carried by a spool frame in working position and the respective gripper, each said spool 10 U-shaped and in all positions of the gripper exposing the path of travel of the weft-insertion needle across the loom on one and the same side of the said gripper.

2. A loom according to claim 1 in which each gripper is individually connected to said first shaft.

Claims

1. A spool-gripper Axminster loom which comprises a frame; a rotatable tubular first shaft in said frame and a solid rotatable second shaft arranged concentrically within said first shaft, yarn grippers spaced along a line parallel to said shafts; a weft-insertion needle moveable along a path which is parallel to said shafts and adjacent said yarn grippers, means including heald means operable to form warp sheds; a spool conveyor chain in said frame; spool frames carried by said spool conveyor chain and protruding therefrom and moveable in succession into working position within the range of said yarn grippers; spaced engagement fingers on each spool frame; spaced lever means pivotally supported at their one ends in said frame and at their other ends having notch means for engagement by the said engaging fingers of the respective spool frame which is in working position, means for actuating said lever means about the pivotal supports thereof on said frame toward and away from finger engaging position; each gripper having two arm parts and each arm part having two ends, said arm parts being pivotally connected to one another at locations intermediate said ends, corresponding one ends of the two arm parts being formed as complementary jaw members, the other end of one of the two arm parts being fixedly secured to said first shaft and the other end of the other of the two arm parts being operatively connected to said second shaft for opening and closing of said complementary jaw members in response to relative rotation of sAid first and second shafts; said first and second shafts being angularly moveable in unison about the common axis of rotation of said shafts to displace the grippers bodily between first positions thereof in said frame in which yarn ends presented by a spool frame which has been positioned in working position by said conveyor chain can be gripped thereby and second positions in said frame in which yarns gripped by said grippers are laid against the fell of the cloth, means to cut off each yarn between a yarn spool carried by a spool frame in working position and the respective gripper, each said spool frame being steadied by interengagement of said notch means of said lever means and the said engagement fingers of the respective spool frame in working position before said yarn ends are gripped by said grippers; said second shaft being angularly moveable about the common axis of rotation of said shafts to effect the opening and closing of said complementary jaw members; the said arm parts of each of said gripper being generally Ushaped and in all positions of the gripper exposing the path of travel of the weft-insertion needle across the loom on one and the same side of the said gripper.