Patent Publication Number: US-3878587-A

Title: Yarn clamp for a textile machine

Description:
United States Patent Marti 1451 Apr. 22, 1975 [54] YARN CLAMP FOR A TEXTILE MACHINE l.844.433 2/1932 glalzkowitz 274/; IA 2.l6l.46l 6/l939 0 crty -4! L [751 memo&#34; Mar&#34;, swlzerlund 2.386.137 10/1945 Olsson ct al. 24/132 FE [73 Assignee; Suher Brothers Ltd wintenhur 2.506.839 5/l950 Mead E l/I32 HA Switzerland 2.620.533 l2/l952 Prltchctt ..4/l32 WF 2.720.225 l0/l955 Moon 24/132 AA [22] Filed: Jan. 19, 1973 [21] App! NOJ 325,166 Primary Iivaminer-Paul R. Gilliam Attorney. Agent. or Firm-Kenyon &amp; Kenyon Reilly C arr &amp; C hapin [30] Foreign Application Priority Data Jan. 19. I972 Switzerland ()0753/72 57 ABSTRACT [52] US. Cl. 24/132 Q or P clamping l clamp is 1511 1m. (:1. Fl6g 11/00 a Pmlem [58] Field of Search 24/132, 178, 248 CR; P a Yam 3 as a f ceme&#39; Yam 39/263 X mm the clampmg zpne of the jZlWS. The gu1de nose can be integrally formed with the jaw or can be sepa- [56] References cued rately made and secured to the jaw. The side of the nose facing a yam forms a right angle or an obtuse 769 231 :TATES PATENTS 24/248 CR angle with the clamping surface.  
  oss 1.413.690 4/1922 Slocum 24/132 HA 8 Clams, 9 Drawing Figures YARN CLAMP FOR A TEXTILE MACHINE This invention relates to a yarn clamp for a textile machine. More particularly. this invention relates to a yarn clamp for a weaving machine in which the weft yarn bobbins remain outside the shed.  
  Heretofore. various types of yarn clamps have been known for use in textile machines. such as weaving machines. to hold a yarn in place for a determinate time interval during operation of the machine. Generally. the yarn clamps have been constructed with two clamping jaws which engage the yarn by their clamping surfaces with at least one of the clamping jaws being movable towards the clamping surface of the other clamping jaw. In yarn clamps of this type. the two clamping jaws form a clamping gap between their clamping surfaces with the gap being open towards the two sides. i.e.. transversely of the path ofthe yarn. In this way. the jaws are able to engage the yarn which is presented preferably in a tensioned state in the weaving machines. The yarn clamps are usually made with jaws which are as narrow as possible in order to keep the moving masses small and for structural reasons. For example. the jaws are kept narrow to conform with the dimensions of the parts mounting the yarn clamps depending on the type of machine. for example. the gripper shuttle in a weaving machine.  
  Depending upon the nature of the yarn material to be treated. a yarn may be compressed to such an extent in the clamp that parts of the end of the yarn laterally swell out of the gap. Further. if the yarn is not inserted exactly centrally between the yarn jaws. such as by a regulator. or if the yarn clamp is required to simultaneously engage two yarns (weft yarns). for example in the case of a weaving machine for the production of hopsack fabric. parts of the yarn end may project laterally. This is a disadvantage particularly in the use of filament yarns. since each thread thereof consists of a plurality of fibrils. some of which do not pass into the clamping gap in the previously known yarn clamps.  
  During movement of a filament yarn in a longitudinal direction. the loose fibrils may be displaced thereon so that slub-like thickened parts form. Faulty yarns of this kind may result in visible fabric faults. for example. in weaving machines of the above kind in which the weft yarns are. for example. introduced into the shed by gripper shuttles. In addition. the transfer of the yarn from one yarn clamp to another may be adversely affected or even rendered impossible. especially where the yarn is transferred to a gripper shuttle by a yarn regulator. if the yarn ends are only partially engaged. The cooperating parts are therefore required to satisfy very high requirements relative to accuracy and reliability since there is only an interval of about [/50 to H100 second available for opening and closing the yarn clamps taking part in the transfer.  
  Accordingly, it is an object of the invention to ensure reliable guidance of a yarn end which is to be engaged by a yarn clamp.  
  It is another object of the invention to prevent lateral emergence of a yarn from a clamping gap formed by a yarn clamp.  
  It is another object of the invention to increase the operational reliability of yarn clamps.  
  Briefly. the invention provides a yarn clamp. particularly a yarn clamp for textile machinery. with two clamping jaws. each of which has a clamping surface for engaging a yarn within a clamping Zone. with at least one lateral guide nose on at least one of the jaws for guiding a yarn into the clamping surface of the jaw on which the guide nose is disposed. In addition. at least one of the clamping jaws is movable towards the clamping surface of the other jaw.  
  In one embodiment. the guide nose is integrally formed in a one-piece manner with a clamping jaw. Alternatively. in order to provide a very simple construction which can be applied to existing yarn clamps for a relatively small cost. the guide nose can be formed as a fitted member which can be secured to a clamping jaw. for example. by soldering.  
  In order to ensure accurate centering of a yarn to the center of the clamping jaws and. hence. reliable engagement thereof. a clamping jaw can be provided with two guide noses disposed on either side of a line corresponding to the path of the yarn. In this embodiment. the facing sides of the guide noses. as considered in the direction of the path of the yarn. each form a right angle or an obtuse angle with the associated clamping surface.  
  These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:  
  FIG. 1 schematically illustrates a part of a weaving machine operative in connection with a picking operation which utilizes a yarn clamp according to the inven tion:  
  FIG. 2 illustrates a top view of a yarn clamp according to the invention for use in a yarn regulator:  
  FIG. 3 illustrates a partial elevational view of the yarn clamp of FIG. 2 taken in the direction of arrow III in FIG. 2. to an enlarged scale;  
  FIG. 4 illustrates a fragn&#39;lentary view of a modified yarn clamp according to the invention:  
  FIG. 5 illustrates a partial elevational view of the yarn clamp of FIG. 4 taken in the direction of arrow V in FIG. 4;  
  FIG. 6 illustrates a fragmentary view of a further modified yarn clamp according to the invention:  
  FIG. 7 illustrates a partial elevational view of the yarn clamp of FIG. 6 taken in the direction of arrow VII in FIG. 6 to an enlarged scale;  
  FIG. 8 illustrates a view of a yarn clamp for a yarn regulator according to another embodiment of the invention; and  
  FIG. 9 illustrates a partial elevational view of the yarn clamp of FIG. 8 taken in the direction of arrow IX in FIG. 8 to an enlarged scale.  
  Referring to FIG. 1, a gripper shuttle weaving machine has weft bobbins 11 (only one is shown) disposed outside a shed 10 as is known. A weft yarn 12 coming from the bobbin 11 is guided through a yarn brake 14 provided with a brake shoe 15, an eye 16 of a yarn tensioner 17 which is pivotable about a pivot 18, and through a fixed eye 19 to a yarn regulator (yarn retainer) 21, in which the yarn 12 is clamped. The end of the weft yarn 12 projects from the yarn regulator 21. The yarn regulator 21 is shown in the position in which the projecting weft yarn end is transferred to a shuttle (gripper shuttle) 22. The shuttle 22 is guided in a picking mechanism (not shown) and is projected through the shed 10 for each pick by a lever 24 disposed on a pivot 23 as is well-known.  
  After a picking operation. the shuttle 22 passes a cutter 25, which is movable out of the picking line. and two selvedge yarn clamps 26 which are disposed on either side of the shed l and which are also movable out of the picking line. and passes to a catching mechanism 27. The shuttle 22 is braked by a shuttle brake 28 in the catching mechanism 27 and is finally returned to an end position 22a from position 22 by means of a pusher 20. During the picking operation. the yarn regulator 21 is guided out of the position illustrated towards the cutter 25 as is known.  
  During the picking of the shuttle 22. the brake shoe is released. At the same time. the yarn tensioner l7 performs a pivoting movement adapted to the speed of the shuttle 22 until the eye 16 passes out ofthe position illustrated into a position between the yarn brake 14 and the eye 19. Towards the end of the pick. the weft yarn 12 is braked by operation of the yarn brake 14; and the yarn tensioner 17 is swung back so that the weft yarn 12 is deflected between the yarn brake l4 and the eye 19. After the pick has been completed. when the shuttle 22 is pushed back. an appropriate movement is initiated to pull back the weft yarn 12 so that the yarn 12 is kept taut.  
  The weft yarn 12 is held by the two selvedge yarn clamps 26 and by the yarn regulator 21 which is guided towards the cutter 25, and then cut by the cutter which is moved into the picking line. while the shuttle 22 is freed from the end of the yarn. returned to the picking mechanism via a transport device (not shown) and prepared for the next pick. The yarn regulator 21 is then returned into the position shown in FIG. 1 together with the cut weft yarn end. the yarn end being kept ready in this position for the next pick. When the yarn regulator 21 is returned. the weft yarn 12 is also pulled back or kept taut by the yarn tensioner 17. The yarn tensioner l7 terminates a pivoting movement by moving into the position shown in FIG. 1.  
  Referring to FIG. 2, the yarn regulator 21 contains a yarn clamp I having two two-armed levers 2, 3 which cooperate tongs-fashion and which are each mounted on a pivot 5 on a support 4. As shown. the levers 2, 3 each extend longitudinally on an opposite side of the yarn path in substantially parallel relation to the yarn path. The two cooperating ends of the levers 2, 3 are constructed as flat clamping jaws 6, 7 which engage the yarn 12 between respective clamping surfaces 8, 9 the yarn end 12a projecting from a clamping zone. The jaws 6, 7 are pivotally mounted via the levers 2, 3 for movement towards and away from each other and the clamping surfaces 8. 9 are disposed in facing relation to each other on either side of the straight line corresponding to the path of the yarn through the clamp prior to and during clamping of the yarn.  
  Referring to FIG. 3, the bottom clamping jaw 6, as viewed. is provided with two guide noses 31, 32 which project beyond the clamping surface 8 and which are positioned at the outer sides of the bottom clamping jaw 6 in facing relation to the yarn end 12a. The facing flanks of the noses 31, 32 each define an obtuse angle with the clamping surface 8 and form a channel-like guide with the clamping surface 8 for the yarn 12. In order to protect the yarn 12, the clamping surface 8 is bevelled in the zone between the guide noses 31, 32.  
  Referring again to FIG. 2, the yarn clamp l is shown in a normally closed position in which the two free arms of the levers 2, 3 are loaded by two limbs 33 of an outwardly expanding spring. so that the clamp jaws 6, 7 are pressed against one another and against the yarn 12. The yarn clamp l is opened by a fork (not shown) which is controlled by the machine drive and which is guided by two limbs 34 in known manner from the side against the outside of the free arms of the levers 2, 3 and presses the levers 2, 3 together against the action of the limbs 33. The yarn clamp 1 opens correspondingly and the yarn 12 is released. for example for picking. In order to re-engage a yarn end. the fork is moved back so that the arms of the levers 2, 3 again pass into the illustrated position by the action of the spring limbs 33. The yarn 12 is thus engaged and centered in the center of the clamping surfaces 8, 9 by the two guide noses 31, 32. As shown. the clamping surfaces 8, 9 are in parallel relation during clamping of the yarn 12. When the jaws 6, 7 are open. the clamping surfaces 8, 9 are in facing relation.  
  Referring to FIGS. 4 and 5, a yarn clamp 35 can alternatively be provided with two clamping jaws 36, 37 which are each provided with a lateral guide nose 40, 4I projecting beyond an associated clamping surface 38, 39 in a direction towards the opposed jaw. One guide nose 40 is disposed on the outside of one clamping jaw 36, and the other guide nose 41 is disposed on the inside of the other clampingjaw 37. Also, each nose 40, 41 is constructed with a flank which is at a rightangle to the respective clamping jaw 38, 39 and which allow a greater clearance in the guidance of the yarn 12 which is to be engaged. As shown in FIG. 4, the two clamping surfaces 38. 39 are each interrupted by a recess 42 extending transversely of the direction of insertion of the yarn 12, so that the clamping effect of the yarn clamp is improved. Also. as shown in FIG. 5, the clamping surfaces 38, 39 are bevelled in the region of the guide noses 40, 41.  
  Referring to FIGS. 6 and 7, a yarn clamp 45 can also have clamping jaws 46, 47 in which the bottom clamping jaw 46 is provided with two guide noses 48. 49 on the inside. Further. the facing flanks of these noses 48, 49 can be substantially V-shaped to allow very accurate centering of the yarn 12.  
  Referring to FIG. 8, the yarn regulator 21&#39; has a yarn clamp 51 formed from a resilient clip secured to a support 52 with rivets 53. This clamp 51 has two limbs 54, 55 which are prestressed. so that their ends, which are constructed as clamping jaws 56, 57 are pressed against one another and against the yarn 12 inserted between their clamping surfaces 58, 59. A fitting in the form of a plate 61 is disposed at the outside of the bottom clamping jaw 56, and is secured thereto as by soldering. This plate 61 has lateral guide noses 62, 63 formed thereon as shown in FIG. 9 which project beyond the clamping surface 58. The facing flanks of the two guide noses 62, 63 each form an obtuse angle with the clamping surface 58.  
  The yarn clamp 51 is shown in the closed position. In order to open the yarn clamp 51, two outwardly expanding openers 64 (FIG. 8) controlled from the machine drive (not shown) are guided from the side towards the inside of the clamping limbs 54, 55 so that the clamping jaws 56, 57 are moved apart and the yarn 12 is released.  
  The gripper shuttle 22 is also provided with a yarn clamp which is constructed similarly to the yarn clamp 51. Of course. yarn clamps of this kind may also have clamping jaws or guide noses of any of the forms described above.  
  A yarn clamp as described above may also be used on other parts of textile machinery. for example on a weft picker needle.  
  Various other embodiments of the invention are also possible. For example. with appropriately constructed clamping jaws only a single guide nose may be required on one of the clamping jaws. Furthermore. for example. a pin fitted into or onto a clamping jaw may act as a guide nose. and the guide nose may also engage. for example. in a corresponding recess ll. the other clamping jaw. Finally. for example. just one of the clamping jaws may be of movable construction and cooperate with a fixed clamping surface.  
  The invention thus provides a yarn clamp of simple construction which can reliably center and clamp a yarn in place.  
  Further. as the guide nose or noses are sized to project in overlapping relation with an opposite clamping jaw. a yarn can be more positively retained within the gap defined by the clamping jaws.  
 What is claimed is:  
 l. A yarn clamp for textile machinery comprising two clamping jaws. each jaw having a flat clamping surface for engaging a yarn within a clamping zone. at least one of said clamping jaws being movable towards said clamping surface of the other of said clamping jaws and at least one of said clamping jaws having at least one lateral guide nose outside said clamping zone for guiding the yarn into said clamping zone. said nose projecting beyond said clamping surface on said latter one clamping jaws to overlap said other jaw. said flat clamping surface being disposed in facing relation to each other on either side of a straight line corresponding to the path of the yarn through said clamp prior to clamping of the yarn and in parallel relation during clamping of the yarn therebetween.  
  2. A yarn clamp according to claim 1 wherein said guide nose is a titted member secured to said one clamping jaw.  
  3. A yarn clamp according to claim 2 wherein said one clamping jaw has two of said guide noses disposed on either side ofa line corresponding to the path of the yarn. said nose having facing sides relative to the direction of the path of the yarn. each nose forming at least a right angle with a respective clamping surface.  
  4. A yarn clamp according to claim 1 wherein said one clamping jaw has two of said guide noses disposed on either side of a line corresponding to the path of the yarn. said noses having facing sides relative to the direction of the path of the yarn tongue each nose forming at least a right angle with a respective clamping surface.  
  5. A yarn clamp according to claim 1 wherein said nose is integral with a respective clamping jaw.  
  6. A yarn clamp according to claim 1 wherein said clamping jaws are resiliently biased together.  
  7. A yarn clamp as set forth in claim 1 wherein said jaws are each pivotally mounted for movement towards and away from each other.  
  8. A yarn clamp as set forth in claim 7 wherein said jaws are each mounted on a respective lever. each said lever extending longitudinally on an opposite side of the yarn path in substantially parallel relation to the yarn path.