SE504096C2 - Yarn grippers for yarn feeding systems in looms - Google Patents

Abstract

The invention refers to an improved yarn holding device for yarn feeding systems in looms, which yarn holding device consists of circular free-rotating grip plates which on the opening of the yarn holding device can rotate and change contact surfaces for the yarn fed through the yarn holding device. This type of yarn holding device offers high wear resistance and self-adjustment of the parallelism between the gripping surfaces over the yarn. At least one grip plate (4) is form locked anchored in a semi spherically shaped holder (22) which has a radius R whose centre of curvature coincides with the pull rod's centre axis CC and the grip plate's (4) plane. The holder (22) is ball-joint housed in a bearing washer (21) and by means of an adjustable lock nut (23) the tolerance in the bearing can be reduced at the same time as the holder retains its flexibility in the bearing surfaces. The lock nut's (23) fixing of the holder (22) and the holder's form locking (25) of the grip plate (4) prevents the grip plate (4) following with the opposite grip plate's opening movement. This enables a quieter gripping function with a prolonged service-life for the component parts, where interference to the yarn feeding is reduced to a minimum.

Description

504 096 and 2 20 25 30 35 A variant of yarn grippers with gripping plates made of special steel is shown in fi gm '1 where rotating round special steel plates were used in the yarn gripper's nip, which means that the plates can rotate and change new surfaces for the line wear running across the tiles. The plates index new new surfaces due to of the yarn fed into the nip. These yarn grippers with round special steel plates even provide better abrasion resistance than what can be obtained with yarn grippers with fixed ceramic plates, thanks that new nip surfaces at the opening of the gamgpen pair can be indexed forward to expose the wear from the yarn The yarn gripper in fi gur 1 is an electrochemical mechanical gripper with a response that is adapted for high-speed type looms, mainly shuttle-free looms. The gamma gripper includes an electromagnet whose coil 17 acts on an anchor 7, on which anchor 7 is arranged via a drawbar 6 one of the plates 3 which by the electromagnet can affect the pinching over the yarn 2. The gripping plate 3, hereinafter called active gripping plate, is circular with a center hole which is entered on the drawbar 6 from its anchor end opposite end, and is held in a fixed position axially with the drawbar between a shoulder of the drawbar and a locking nut 5, which locking nut is likewise entered on the drawbar 6 from its anchor end opposite threaded end. The second gripping plate 4 pinching over the yarn, hereafter called passive gripping plate, it is also circular with a center hole 10 which center hole with a clearance is fi- running on the drawbar 6. The passive gripping plate 4 is mounted on an entrained around the drawbar cirlmal is a censor washer 11, the axial abutment surface of which of the passive grip plate 4 is bowl shaped. By the abutment surface of the passive gripping plate against the centering washer 11 on correspondingly is cup-shaped, the passive gripping plate 4 can be made self-correcting with respect on the parallelism with the cooperating nip surface of the active clamping plate 3.

The gamma gripper 1 comprises a mounting pea 13 with mounting holes 13 'for mounting on a bracket. on the loom. In Figure 1, this mounting fl äiis is arranged between a fixedly arranged on the fl end. wear washer 12, against which the centering washer 11 abuts, and the housing 15 of the electromagnet. The housing 15 accommodates in a conventional manner a coil 17 wound around one with the drawbar and the anchor 7 concentric bobbin 16.

The yarn gripper works in such a way that when the spool is energized, the anchor 7 is pulled towards an anchor stop 18 whereby the active gripping plate 3 of the gripper is actuated from the passive gripping plate 4 and opens the nip between the plates. When the voltage is switched off, a return fi spring 8 on one fl ends 7 'pushes on the anchor 7 so that the active gripping plate 3 pinches the yarn 2 against the passive gripping plate 4.

Because the plates 3 and 4 can rotate around the gamma gripper's axis line CC, they come continuously over the yarn pinching the surfaces to be changed, which is shown in Figure 2 where the gripping plate 4 is seen in a view seen in the section Il-H indicated in Figure 1. The yarn 2 passes over the gripping plate in the feed direction, called FEED in fi gurema. Because the gripping plate can rotate, in the direction ROT, around the shoulder line CC so comes the line bearing of the gripping plate against the yarn is continuously changed. The friction of the yarn tends to rotate the gripping plate in the direction ROT and with the lines A, B and C respectively the line types are indicated as 20 25 30 3 504 096 obtained, for example, during the third, second and immediately preceding pinching of the yarn, respectively The wear will hereby be evenly distributed over the plates. The alniva grip plate 3 is in it preferred embodiments locked on the drawbar 6, but then the drawbar 6 together with the gripping plate 3 and the armature 7 constitute a unit which rotates freely in the housing around the cenum shaft CC, so also the active gripping plate to be able to rotate with this unit and continuously change line abutment with garnet 2.

A disadvantage of this type of yarn gripper is that the passive gripping plate is not axially axially the direction of the center axis CC, which means that the passive gripping plate tends to adhere to the the active gripping plate when the active gripping plate moves to open the nip. This results in it the passive gripping plate 4 lifts and disturbs the feeding of the yarn between the plates 3 and 4, which can result in the yarn is exposed to braking forces that can cause yarn breakage. In shuttle-free looms, it can undesired braking torque on the yarn means that the yarn is not pushed all the way into the warp, thereby the weaving becomes incomplete and can be stopped.

Another disadvantage is that the passive gripping plate due to the large radius of the bowl shape in the abutment surfaces between the passive gripping plate 4 and the centering washer 11 have an anxious behavior, as the yarn feed over the nip surface of the passive gripping plate tends to push the passive gripping plate radially in the feed direction of the yarn FEED when opening and closing the nip when the gripping plate is not parallel. With each pinch, the passive gripping plate 4 will return to the radial position as provides parallelism with the active grip plate, which causes noise and disturbances in the gamma feed.

Another disadvantage is that the yarn gripper can only be mounted so that the center axis CC lies vertically, with the active grip plate on top. Other mounting directions would mean that it the passive plate may accompany the active gripping plate and interfere with the yarn matting.

PURPOSE OF THE INVENTION The purpose of the invention is to obtain an improved yarn gripper which has all the advantages as one yarn grippers with circular free-rotating gripping plates have with respect to wear resistance as well self-adjustment of the parallelism between the surfaces gripping the yarn but where it The suitable yarn gripper reduces the disturbances on the yarn feeding through the yarn gripper.

Another object is to obtain a quieter gripping function with the universal type of yarn gripper with an extended service life of the parts included in the gamgriper, where lateral movements in the yarn feeding direction and axial movements across the yarn feeding direction are reduced by at least that of the gripping plates which is self-adjusting for parallelism adjustment relative to the other cooperating gripping plate 504 096 9 20 25 Another purpose is that the yarn gripper should be curved mounted so that the center axis CC can assume which angular position at any time in a vertical plane across the yarn feeding direction, without the passive gripping plate may interfere with yarn feeding, BRIEF DESCRIPTION OF THE INVENTION The gamma gripper according to the invention is characterized by the characterizing part of claim 1.

Through the inventive yarn gripper, circular free-rotating gripper plates can obtain a significantly extended service life for a guaranteed yarn gripping function, where at the same time the disturbances on gamma feeding has been reduced to a minimum. The other distinctive features and advantages of the invention appear from the other patent claims characteristic parts and the following description of exemplary embodiments.

The description of exhaustion examples is made with reference to fi gures stated in the following fi guríörteclming.

LIST OF FIGURES Figure 1 shows a previously known vulture gripper which was initially described in the section Technology Position; Figure 2 shows a view seen in the section II-II in Figure 1 how the game continuously changes line abutment towards the over the yarn pinching circular gripping plates in the type of yarn gripper in question; Figure 3 shows a yarn gripper in accordance with the invention, Figure 4 schematically shows a yarn feeding system for a loom with one in the yarn feeding system arranged gamgripare.

DESCRIPTION OF PERFORMANCE DRIVE Figure 3 shows an embodiment of the inventive yarn gripper where the anchor, the drawbar and the active gripping plate are exposed relative to other parts which are seen in a section through the yarn gripper.

The details that have the equivalent of details in the game gripper shown in fi gur 1 hari fi gur 3 have been added same reference numerals. The gamma gripper housing 15 and the electromagnet 16,17 arranged in the housing are essentially identical to housings and electromagnetic 1 gur 1.

The anchor 7 and the associated tie rod 6 actuate one movable active gripping plate 3 on corresponding to that in Figure 1, i.e. when the electromagnet is activated, the active the gripping plate 3 away in the axial direction CC of the drawbar for releasing the yarn which is fixed between it the passive gripping plate 4 and the active gripping plate 3 when the electric magnet is deactivated. 10 20 30 35 5,504,096 In the inventive gamma gripper, the passive cast plate 4 is arranged in a hemisphere shaped holder 22. The cut surface of the holder 22 is in a non-conventional manner completely blackened in order to increase The convex surface of the hemispherical holder 22 is directed away from the passive grip plate. The hemispherically shaped holder 22 has a concave and a convex surface where it is in it the gripping plate 4 arranged on the half-shaped holder lies as a lid over the concave surface of the holder.

The passive gripping plate 4 is held around its outer periphery to the hemispherical holder 22. outer periphery by means of an anchoring member 25. The anchoring member 25 is shown in the outer liner a form lock in which a groove running along the outer edges of the hemispherically shaped holder is entered over a corresponding phase on the outer periphery of the passive gripping plate.

The hemispherically shaped holder is suitably made of a low friction type polymer material, for example te fl on, which material has a certain limited ibil flexibility that allows the holder 22 and its grooves can be tilted over the fixed outer periphery of the passive gripping plate.

The semi-star-shaped holder 22 is stored with its convex surface in a relatively housed housing bearing tray 21 which bearing tray has a corresponding concave bearing surface against which the holder convex surface abuts.

The bearing surfaces between the holder 22 and and the bearing washer 21 are convex and concave, respectively, with a radius R relative to the center axis CC of the drawbar. The holder 22 can hereby adjust so that parallelism is obtained in the abutment surfaces between the active gripping plate 3 and the one arranged at the housing passive grip plate 4.

The bearing washer 21 can be attached to the mounting end 13 arranged on the housing by gluing, welding or screwed on a threaded extension 24 of the anchor stop 18 which extension is arranged concentrically around the drawbar 6.

The holding member 22 is held against the bearing washer with a locking ring 24 which abuts against a concave surface in the hemispherically shaped holder 22. The locking stitch 24 is preferably screwed onto the threaded extension 24 of the anchor stop and its clamping force against the holder 22 is regulated by the tightening force on the locking ring However, the locking ring 23 is only tightened so much that the clearance between the locking ring and the inner concave of the holder 22 surface is minimized and the mobility of the bearing surfaces between holder 22 and the bearing washer is maintained. After tightening of the locking member, this is fixed in position by means of the internal thread of the locking member 23 by means of locking means can be locked against the external thread on the projection 24 projecting from the housing.

For example, locking fluid of type LOCTH "E or similar can be used. Alternatively, locking can be done with a locking screw that engages against the threaded action.

The bearing surfaces between the holder 22 and the bearing washer 21 have a constant curvature with the radius R and its The center of smoke should preferably be in the center axis CC of the drawbar and in the passive one gripping plate 4 planes. The passive gripping plate 4 then absorbs the forces to which it is subjected by it through the gap fed the game 2. With the gar fl fvriparen in ñgur 1 a restless lateral movement is obtained on the 504 096 ß 10 20 25 30 35 passive gripping plate as the large radius of its abutment surface causes the passing yarn to tend lift the passive gripping plate in the feed direction FEED.

Correspondingly, the concave surface of the holder has a constant smoking radius (R) where the smoking center coincides with the centrifuge shaft (CC) of the drawbar and the gripping plate (4) arranged in the holder plane, and the abutment surface of the locking member (23) abutting the concave surface of the holder has a the concave surface of the hob corresponds to the convex surface.

The half-star-shaped holder 22 is in fi gur 3 turned on the extended part of the anchor stop and is provided with a sufficient clearance between its entry hole and the extended part of the anchor stop to enable the parallelism setting between the plates 3,4.

Figure 4 schematically shows a yarn feeding system for a shuttle-free loom 47 with a yarn feeding system arranged yarn gripper 34. Only one yarn feeding system is shown in the yarn. IN automated looms, there are usually a number of parallel yarn feeding systems, whereby change of yarn with, for example, a different color can be done during the weaving between different successive elements.

Via a gamma magazine 31, also called foumisseur, the yarn 2 is fed via a yarn guide hopper 32 and a yarn guide 33 to the yarn gripper 34. The yarn is led after the yarn gripper 34 on to a second yarn guide 35 and up to a water jet nozzle 36.

The water jet nozzle 36 then inserts the yarn 2 into the warp between the threads of the warp being lifted. hereinafter referred to as the upper warp 39, and the threads in the warp being lowered, hereinafter referred to as the lower warp 40.

The yarn 2 is pushed in between the upper and lower warps 39,40 with the help of a small drop of water which with high pressure is pushed out of the water jet piece and then the yarn 2 takes with it. Pressurized water is supplied to the nozzle of the water jet fuser from a pressure source P via an adjustable valve V. The valve V opens very quickly and only a small drop of water leaves the nozzle 36 and pulls the game 2 with it.

With a knife unit 37, the yarn can be cut off after the yarn has been fed into the warp. The knife unit can be provided with cutting edge or hot melt threads burn off the yarn which often used in weaving with polyester yarn. The knife unit 37 is preferably arranged close to the warp or weave 38 in order to minimize yarn waste.

The feed system is monitored by a controller 41 which can be reprogrammed with a laptop hand terminal 42 for adaptation to different types of yarns m.a.p the current weight of the yarn e.t.c.

For example, heavier or stiffer yarns may require a larger drop of water or higher pressure to be able to pull the yarn through the warp The control unit 41 regulates the function of the various units, via control signal lines 50.5l, 52.53 connected to the yarn magazine 31, the yarn gripper 34, the water jet nozzle control valve V and the knife unit, respectively 37. The synchronization of the units 3 l, 34, V and 37, respectively, to the plant tool 47 takes place depending on inputs on a line 59 from, for example, a sensor 45 detecting the rotation of the loom 20 25 30 35 504 096 feed counters 44 and thus the length of the finished fabric, in combination with other input lines 58 from sensor 46 arranged on the loom 47.

As stated above, the holder 22 is suitably made of a polymeric material while the locking ring 23 and the bearing washer 21 are made of, for example, some aluminum alloy. The choice of material is governed by the requirements for low friction while maintaining mobility in the contact surfaces between the holder and the bearing washer 21 / locking ring23, as well as the requirements to maintain a given game between the holder for longer operating periods and the cooperating bearing surfaces of the bearing washer. In another variant, the holder 22 can instead be manufactured in aluminum because the locking ring 23 and the bearing washer 21 are made of polymeric material.

Within the framework of the patent claims, the invention can be modified in a number of ways. The free-rotating ones circular gripping plates 3,4 may, for example, be coated with ceramic material, alternatively that grip plate dryers in their entirety are made of ceramic material. The essential thing is that the grip plates retains its free-rotating properties to enable continuous change of yarn wear linieanligsnina på s fi pytßrrl fl- The locking sleeve 23 in the preferred embodiment can also be replaced with another construction such as ensures that the holder does not follow when the active gripping plate is actuated for opening. Holder 22 i 3 gur 3 can, for example, in its lower part be provided with a concentrically arranged with the drawbar sleeve directed from the convex surface of the holder which sleeve has a radially outwardly directed collar which grips into a radial groove arranged internally in the lead-through of the bearing washer 21 for the drawbar 6.

The yarn gripper can also be modified in such a way that both gripping plates are stored in separate hemispherical holders. if improved and increased reliability in the parallelism setting is desired. If, for example, a holder should jam, the other holder can provide the required parallelism adjustment. This causes however, a disadvantage with respect to the yarn gripper's response. Most often they are sought after in the yarn grabber the moving parts that are affected to open the nip must have as low a weight as possible, which means that the yarn gripper shown in Figure 3 is preferred. In Figure 3, only the anchor 7, the drawbar 6 is affected and the tip plate 3 arranged on the drawbar, which gives a low weight to the movable parts and rapid response when the electromagnet is activated or deactivated for opening and closing, respectively. With the embodiment shown in Figure 3, a response of the order of 3 milliseconds is obtained, which is a prerequisite for obtaining a high speed of weaving and faster yarn wetting. In a further variant, both gripping plates can also be movable, and are affected by the same or by each drawbar with associated electromagnet. In other applications, the servo member may also be of the arm type other than an electromagnet, for example hydraulic or pneumatic cylinders.

Claims (10)

504 096 5 '10 20 25 30 PATENT REQUIREMENTS Yarn gripper for intermittent holding of, for example, wire yarns and corresponding yarn feeding systems for looms, wherein the yarn gripper comprises two circular gripping plates (3,4) where each gripping plate lies in a plane parallel to the yarn feeding direction (FEED) and on either side of the feed between the gripping plates. the yarn (2), wherein at least one gripping plate (3) is operable away from or towards the other gripping plate (4) for opening and releasing the yarn fed between the gripping plates (3,4) and closing and holding the intermediate gripping plates (3), respectively. , 4) fed yarns, via a drawbar (6) which can be actuated by servo means (8,19), which drawbar is arranged perpendicular to the yarn feeding direction (FEED) and the plane of the gripping plates and is connected to or through the center of the gripping plates, and where respective gripping plates (3,4) are rotatable nmt the center axis (CC) of the drawbar! that at least one of the gripping plates (4) is arranged in a semi-star-shaped holder (22) with a concave and a convex surface where the gripping plate (4) arranged in the semicircular holder lies as a lid over the concave surface of the holder and where the holder outer edges by means of anchoring means (25) hold the gripping plate (4) nmt its outer periphery, -that the convex surface of the holder is mounted in a bearing washer (21) which is formed with a concave shape corresponding to the convex surface of the holder which enables rotation and at least a limited inclination of the holder relative to the center axis (CC) of the drawbar, and that the holder (22) is formed with the locking means (23) cooperating with the gripping plate, which locking means prevent the holder from following the opening movement of the second gripping plate (3) away from the gripping plate arranged in the hemispherical holder. Yarn gripper according to claim 1, characterized in that the hemispherical holder (22) is axially relative to the yarn gripper housing (15) in the axial direction of the drawbar by means of a locking member (23) abutting the concave surface of the hemispherical holder, which locking means is held to the housing by a projection (24) cooperating with the locking means and projecting from the housing, which projection is arranged coaxially with the center axis (CC) of the drawbar. Gamma gripper according to claim 1 or 2, characterized in that the convex surface of the holder (22) has a constant radius of curvature where the center of curvature coincides with the center axis (CC) of the drawbar and the plane of the gripping plate (4) arranged in the holder. 10 20 25 30 35 2 504 096 A gamma gripper according to claim 2 or 3, characterized in that the concave surface of the holder has a constant radius of inclination (R) where the center of smoke coincides with the center axis (CC) of the drawbar and the plane of the gripping plate axis (4) arranged in the holder, and surface abutment The abutment surface of the locking member (23) has a convex surface corresponding to the concave surface of the holder. Yarn gripper according to claim 2, 3 or 4, characterized in that the locking means (23) has an internal thread which is screwed onto a corresponding external thread on the projection (24) projecting from the housing, whereby the locking means can be adjustably screwed on for elimination of play between locking means (23) and holder (22) and between holder (22) and bearing washer (21) but while maintaining the mobility of the abutment surfaces between the holder and the locking means and bearing washer Yarn gripper according to claim 1, characterized in that the anchoring means (25) is a front locking where a groove running along the outer edges on the concave side of the hemispherical holder is entered over a corresponding radially directed phase on the outer periphery of the gripping plate arranged in the holder. (4). Yarn gripper according to Claim 5, characterized in that the internal thread of the locking member (23) can be locked by means of locking means against the external thread on the projection (24) projecting from the housing (15). Yarn gripper according to one of the preceding claims, characterized in that the holder (22) is made of a polymer material of the low-friction type and where the bearing washer (21) and the locking member (23) are made of metal, for example an aluminum alloy. A yarn gripper according to any one of the preceding claims, characterized in that the hemispherical holder (22) is ball-likely mounted to the housing of the yarn gripper (15) and holds a first of the gripping plates (4) in a centered position relative to the center axis (CC) of the drawbar, where the second gripping plate (3) is fixedly connected to the drawbar (6). Yarn gripper according to claim 9, characterized in that the drawbar (6) is fixedly connected to an anchor (7) which anchor is actuated via a spring (8) towards a first end position, and where the anchor (7) is actuated by an electromagnet ( 16,17) can be actuated against a second position and against the action of the på on the anchor, which end positions entail holding and releasing the yarn which passes between the gripping plates (3,4).