Patent Publication Number: US-3875974-A

Title: Device for controlling gripper shuttles in looms

Description:
Rambousek Apr. 8, 1975 DEVICE FOR CONTROLLING GRIPPER SI-IUTTLES IN LOOMS [75] Inventor: Zdenek Rambousek, Liberec,  
 Czechoslovakia [73] Assignee: Elitex, Zavody textilniho strojirenstvi generalni reditestvi, Liberec, Czechoslovakia [22] Filed: Apr. 10, 1974 [21] Appl. N0.: 460,421  
 [30] Foreign Application Priority Data Apr. 18. 1973 Czechoslovakia 2775-73 [52] U.S. Cl. 139/125; 139/155; 139/185;  
  139/342 [51] Int. Cl.. D03d 47/24; D03d 49/54; D03d 51/40 [58] Field of Search 139/122 R, 125, 126, 155, 139/183, 185, 186, 341, 342, 343  
 [56] References Cited UNlTED STATES PATENTS 3,332,452 7/1967 Mzyk et al. 139/341 3,487,860 l/l970 Suaty et al. 139/125 3,563,281 2/1971 Pfarrwaller 139/342 Primary Examiner-Henry S. Jaudon [57] ABSTRACT The present invention relates to a device for controlling gripper shuttles looms, particularly those provided with rotary shuttle boxes at both sides thereof. By said device, the gripper shuttle can be efficiently braked upon its arrival at the shuttle box and can be prevented from undesirable recoil into the shed. The device brakes the arriving gripper shuttle along a relatively longer path, but returns the shuttle immediately afterwards in a controllable manner at least partially into the shed, and gradually adjusts the shuttle in the immediate proximity of the selvedge, by cooperation of a weft thread tensioning device on the other side of the loom, so that the weft thread and unthreaded from the gripper shuttle does not excessively project over the fabric selvedge. In accordance with the invention, a braking box is arranged parallel to the guideway of the gripper shuttle in each shuttle box, said braking box being movable in both the radial and longitudinal directions relative to the said guideway of the gripper shuttle, and comprising a braking jaw mounted in an elastic medium and a swingable pawl with a free end located beside the end of said braking box, and a picker with an elastic member mounted beside said braking box and further in the direction of arrival of the gripper shuttle. Said picker is movable in both the radial and longitudinal directions relative to the guideway of the gripper shuttle in the shuttle box, and a stop motion feeler mounted within the range of action of the said free end of the swingable pawl.  
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 DEVICE FOR CONTROLLING GRIPPER SHUTTLES IN LOOMS This application is related to the coassigned application of Bilek. Ser. No. 461,412, filed Apr. l6. 1974 which is based upon Czechoslovakian Patent Application No. PV 2774-73. filed Apr. 18. I973.  
  The present invention relates to a device for controlling gripper shuttles in looms. particularly those pro vided with rotary shuttle boxes at both sides thereof. By  
 .said device, the gripper shuttle can be efficiently braked upon its arrival at the shuttle box and can be prevented from undesirable recoil into the shed. Further, said device can check the correctness of the position of the gripper shuttle and transfer it temporarily, before its adjustment to a position suitable for inserting a new weft thread. partially back into the shed. where said gripper shuttle remains until the moment at which the warp threads begin to interlace the inserted weft thread.  
  In looms with gripper shuttles. using a cut weft thread. particularly with one gripper shuttle turning at its reversing points through 180, a certain loss of weft thread occurs due to the excessively long weft thread ends projecting over the selvedge.  
  Heretofore. it was necessary for unthreading the end of the inserted weft thread from the gripper shuttle to make the gripper shuttle completely leave the shed.  
 The inserted weft thread was tensioned from the other side of the loom, this being inaccurate and the projecting weft thread ends being quite long. The said projecting ends were inserted either into the next shed or cut off.  
  In order to obtain projecting weft thread ends as short as possible. it has been attempted to brake the arriving gripper shuttle along the shortest possible path. However. on a short braking path. the braking of the gripper shuttle is too hard and causes an excessive wear of both the braking jaws and the damper inside the shuttle box.  
  It is more advantageous to have a device which brakes the arriving gripper shuttle along relatively longer path, but which returns the shuttle immediately afterwards in a controllable manner at least partially into the&#39;shed, and which gradually adjusts the shuttle in the immediate proximity of the selvedge, by cooperation of a weft thread tensioning device on the other side of the loom, so that the weft thread end unthreaded from the gripper shuttle does not excessively project over the fabric selvedge. This problem is solved by the device according to the present invention.  
  In accordance with the invention a braking box is arranged parallel to the guideway of the gripper shuttle in each shuttle box, said braking box being movable in both the radial and longitudinal directions relative to the said guideway of the gripper shuttle, and comprising a braking jaw mounted in an elastic medium and a swingable pawl with a free end located beside the end of said braking box. and a picker with an elastic member mounted beside said braking box and further in the direction of arrival of the gripper shuttle. Said picker is movable in both the radial and longitudinal directions relative to the guideway of the gripper shuttle in the shuttle box, and a stop motion feeler mounted within the range of action of the said free end of the swingable pawl. I  
  Further advantages and features of the present invention are described in the following specification which obviously does not include all possible embodiments of the present invention, and in the accompanying drawings. in which:  
  FIG. 1 is a diagrammatic view in elevation of the driving mechanism and the slay of the loom, illustrative embodiment of the device according to the present invention being shown mounted on the loom;  
  FIG. 2 is a view on an enlarged scale partially in elevation and partially in section of the device at the right side of the loom, the view showing the arrangement of the braking box and the picker at the ends of two arm levers mounted swingably on a transversal carrier and controlled by cams on the control drum;  
  FIG. 3 is a view in longitudinal section through the braking box and the picker in their basic position when observed from above before the arrival of the gripper shuttle, the stop motion feeler and its electric circuit being shown diagrammatically;  
  FIG. 4 is a view similar to FIG. 3, but showing a partial penetration of the gripper shuttle into the shuttle box and its braking by the braking jaw in the braking box;  
  FIG. 5 is a view similar to FIG. 3, but showing the gripper shuttle completely stopped after its arrival and braking by the braking jaw by the impact of its front side against the buffer of the picker;  
  FIG. 6 is a view similar to FIG. 3, but with the gripper shuttle being shown after being pressed by the picker into the shed and with the whole gripper box; the correct position of the braking box pawl being controlled by the stop motion feeler;  
  FIG. 7 is a view of the device as shown inf FIG. 3, upon the returning of the gripper shuttle by the action of the pawl in the braking box simultaneously with movement of said braking box and picker into a position suitable for feeding a new weft thread into the gripping mechanism of the gripper shuttle;  
  FIG. 8 is a view similar to FIG. 3 of the device at the moment at which the gripper shuttle did not arrive at the shuttle box at an appropriate speed. the swingable pawl thus having not engaged the edge of the gripper shuttle, the stop motion feeler being swung out upon the moving back of said gripper shuttle, as shown in dot-and-dash lines (or as in FIG. 6), and thereby interrupting the electric circuit of the loom;  
  FIG. 9 is a view in cross-section through the braking box, the gripper shuttle and the shuttle box, the section being taken along line A--A in FIG. 3; and  
  FIG. 10 is a view in longitudinal section through the picker and the braking box, the section being taken along line 8-8 in FIG. 3.  
  The following specification of the device for controlling the gripper shuttle is directed to the device shown on the right side of a loom with rotary shuttle boxes at both sides thereof shown in FIG. 1; the devices employed on both sides of the loom are identical.  
  On the frame 1 ofthe loom (FIG. I) there is mounted the transverse main shaft 2 on which there is rotatably mounted a tube 3. A slay 5 is fastened on slay arms 4 and carries a reed 6 and a guiding comb 7. Reed 6 and guiding comb 7 define a path for the transfer of a gripper shuttle 14 from one side of the loom to the other. The gripper shuttle 14 has a front part 19, a rear surface 20 and an edge (FIG. 4). In a bracket 8 affixed to the frame of the loom there are mounted mechanisms for controlling gripper shuttle 14, i.e., a braking box 9, a picker 10, a control mechanism 11, a rotary shuttle box 12, and a pneumatic ejecting mechanism 13.  
  The loom is driven by a motor 15, which drives via transmission 16 an electromagnetic clutch-brake mechanism 17 mounted on shaft 2 and frame 1. When current flows through terminals 18, which are connected to the control and detecting circuits. the mechanism 17 operates as a clutch. When the current flow is interrupted in either the control or detecting circuit. the mechanism 17 operates as a brake which stops the loom.  
  The braking box 9 (FIG. 2) and picker 10 are movable along the shuttle box 12, and are further movable in a direction perpendicular to the shuttle box 12 so as to be able to move away or deviate from the gripper shuttle 14 at the time of its ejection.  
  For that purpose, the braking box 9 and the picker 10 are fastened at the ends of respective two arm levers 21 and 22 swingable in the plane of the paper of FIG. 2 about pins 24, 25 on a transverse carrier 23 which is mounted by means of pins 31 in bearings in bracket 8. The lower ends (FIG. 2) of two arm levers 21, 22 are provided with pins 26, 27 and cam following rollers which are guided by box cams 29, 30 in the control drum 28 which controls thereby the motions of the braking box 9 of shuttle box 12 and the picker 10.  
  The deviation of the braking box 9 with the picker 10 upon ejection of the gripper shuttle 14 from the shuttle box 12 is controlled by a radial or face cam 32 which controls via a cam follower roller 34 on a lever 33 the transverse carrier 23 for the two arm levers 21, 22. The positive contact of radial cam 32 and roller at all times is achieved by means of a coil tension spring 35.  
  The braking box 9 (FIG. 3) is formed by a hollow body or housing 44 which carries on a pin 45 a swingable pawl 46, the braking box further comprising springs 47 at the left and a spring 48 at the right, which press the wedge-shaped braking jaw 49 upwardly until its outwardly flanged side edges 50 engage the inwardly flanged side edges 51 (FIG. 9) of hollow body 44. A further spring 52 holds the swingable pawl 46 in such manner, that between edge 70 of gripper shuttle l4 and the finger 53 of the swingable pawl 44 there is formed a clearance T The swingable pawl 46 is provided with a surface 69 (FIG. 4). The swinging motion of this pawl 46 is limited by stop 66 inside hollow body 44, which is provided with a projection 67. The shape of finger 58 of the swingable pawl 46 is shown in FIG. 10.  
  Picker 10 is formed by a picker body 56 which carries a buffer 54 on a pin 55, the buffer being supported by a rubber block 57 (FIG. 10). Opposite to the holder of picker 10 there is mounted a trigger rod 36 which passes through guideway 37 in bracket 8. Spring 38 holds rod 36 inside the pit of the lower arm ofa first class lever 39 (FIG. 2) of which the other arm releases the lock 40 of the pneumatic mechanism 13 for ejecting gripper shuttle 14.  
  In FIG. 3 the control mechanism 11 is, for the purpose of clarity shown turned through 90 relative to FIG. 2 into the plane of the drawing. Said mechanism which is fastened to bracket 8, comprises a pivot pin 61 and a feeler in the form of a first-class lever, of which the upper arm is positioned against the front 58 of swingable pawl 46 and the lower arm engages switch 62. The said lower arm of feeler 60 cooperates with a Shuttle box 12 is rotatable about an axis which is perpendicular to the plane of the paper in FIG. 2, the shuttle box being rotated upon feeding a new weft thread into gripper shuttle 14. Because gripper shuttle 14 is onesided, it must be turned for each insertion with its front part in the direction towards the shed. The shuttle box 12 has a dove tail shaped groove (FIG. 9) into which the bottom 42 and side guideways 43 of the gripper shuttle 14 fit. The gap between the reed 6 and the shuttle box 12 is covered by a plate 41, the active surface of which is situated in the same plane as the bottom 42 of shuttle 12, and the active surface of the reed 6. The plate 41 does not prevent rotation of gripper shuttle 14 with shuttle box 12.  
  The electric circuit 71 and switch 62 of electromagnetic clutch-brake 17 is completed by power source 72 and terminals 73, to which there are connected the circuit of warp and weft stop motions (not shown) and the stop (also not shown) press button. The two switches 62 (of both the left and right control mechanism 11) are connected in series with other circuit elements.  
  The not shown stop press button has a parallel arch controlled by a cam (not shown), and thus the loom can be stopped only when slay 5 is in its rear dead center position.  
  In FIG. 4 the weft thread to be inserted is denoted by reference character 74; in FIG. 7, the warp of the selvedge of the fabric being formed is denoted by reference character 75.  
  It is to be understood that the preceding specification and the drawings and mechanisms mainly describe those mechanisms which form part of the present invention, however, the also described mechanical assemblies in which the said mechanisms are located for obtaining a complete understanding of the operation, but which themselves are not the subject matter of the present invention.  
 The device of the invention operates as follows.  
  The gripper shuttle 14, upon arrival at the right side of the loom (FIG. 3) passes under the finger 53 of the swingable pawl 46, which is located a distance Y from the edge of gripper shuttle 14 and enters a wedgelike narrowing gap formed between the plate 41, the bottom 42 of shuttle box 12, and the friction surface 68 of braking jaw 49. The wedge-like braking jaw 49 is made of elastic, light material, and thus upon the enter-- ing of gripper shuttle 14 into said gap of the braking jaw 49 does not recoil; as a consequence, the friction surface 68 thus firmly contacts the whole surface of edge 70 of gripper shuttle 14.  
  The gripper shuttle 14 is intensively braked by the friction between the bottom 42 of shuttle box 12 and the bottom surface of the shuttle and by the friction between the friction surface 68 of braking jaw 49 and the surface of the edge 70 of the shuttle, i.e. on its two parallely arranged surfaces. The side guideways 43 only guides the gripper shuttle 14 for the purpose of keeping it from deviating from its direction.  
  The penetrating gripper shuttle 14 moves the wedge shaped braking jaw 49 inthe direction opposite to the action of springs 47 and 48. The spring 48 begins to act at its other end upon arm 59 of swingable pawl 46, overcomes the force of spring 52, and turns the swingable pawl 46 through a distance Y until the finger 53 of said pawl bears against edge 70 of gripper shuttle 14 (FIG. 4). The gripper shuttle l4 continues its motion to the right (FIG. 3) and the wedge shaped braking jaw 49 is thus moved further by its action against the resistance of spring 48, the bias of which further increases. When the edge 70 of gripper shuttle 14, which is actually formed by edge 70 and surface 20, passes below finger 53 of swingable pawl 46 and over its edge formed by finger 53 and surface 69 of said pawl 46, the bias of spring 48, causes by the lifting of the wedge shaped braking jaw 49, finishes the turning of swingable pawl 46 as far as stop 66 through a distance Y (FIG. 5). The stop 66 is necessary in order that the finger S3 of swingable pawl 46 shall not be located in the path of the rear part of gripper shuttle 14, in which the weft thread 74 to be inserted is gripped. The progessively more intense braking of the gripper shuttle 14 is carried on until its complete stoppage. which can take place even before front 19 of gripper shuttle 14 comes into contact with buffer 54 of picker 10. If the front 19 of gripper shuttle 14 should engage the buffer 54, the damping of such impact is transferred by turning the buffer 54 about pivot 55 to the rubber block 57 which acts as a damping spring.  
 The first purpose of turning the swingable pawl 46 is so that in case of incorrect operation of the wedge shaped braking jaw 49 upon its becoming worn. because of excessive lubrication. or due to a broken spring 47, said gripper shuttle 14 cannot recoil from picker back into the shed. The self-acting operation of pawl 46, which is forced by gripper shuttle 14 via a wedge shaped braking jaw 49 and spring 48, is necessary because the direct lifting of swingable pawl 46 which is controlled by gripper shuttle 14, has still a further advantage. particularly upon controlling the arrival of gripper shuttle 14 into shuttle box 12, which is now described.  
  At the time at which the presence of gripper shuttle 14 in the shuttle box 12 is presumed. it is necessary to return its end (shown at the left in FIG. 4), in which the weft thread 74 to be inserted is gripped. partially into the shed upon the simultaneous retensioning of weft thread 74 by a tensioning device (not shown at the other side of the loom. By a small moving away of braking box 9 and picker 10 from shuttle box 12, the gripper shuttle 14 is unbrakcd, but only to such an extent It should be noted that the arrival of gripper shuttle 14 is controlled by turning the finger 53 of the swingable pawl 46 from its basic position between the arrival of gripper shuttle 14 at first for a distance Y (FIGS. 3, 4) and then for another distance Y (FIG. 5). The total distance of turning Y Y is greater than the distance X (FIG. 3) of the overlap of the front 58 of swingable pawl 46 and the feeler 60 of control mechanism 11, for a distance X (FIG. 5). The relation is as follows: I Y X X Then, upon displacement of braking box 9 in the direction of arrow C and upon the correct positioning of gripper shuttle 14, the front of swingable pawl 46 passes beside the arm of feeler 60 at a distance X and the operation of the loom is carried on. The second purpose of the swingable pawl 46 is thus that by its position it controls the presence of gripper shuttle l4 and limits, moreover, the movement of the gripper shuttle upon its being returned into the shed by picker 10.  
  At a given moment. it is necessary to draw the end of gripper shuttle 14, after releasing the inserted weft thread 74 therefrom, out of the shed and to displace it to the right (FIG. 6), as shown by arrow E through a distance equal to the length of arrow E. This is performed by the common movement of brake box 9 and picker l0. Gripper shuttle 14 is drawn by engagement of surface 69 of pawl 46 with surface 20 of the shuttle. The end position (FIG. &#39;7) is a position in which during beat-up of slay 5 there is inserted a new weft-thread into gripper shuttle 14 for the next insertion of gripper shuttle 14 into the shed in the opposite direction.  
  After inserting a new weft thread into gripper shuttle l4 and its turning for together with gripper box 12 while the braking box 9 and picker 10 are simul taneoulsy moved away from each other, the gripper shuttle 14 is ejected into the shed. The impulse to the ejection is given by movement of picker 10 in its operative stroke in the direction of arrow F (FIG. 7). and is transmitted to the lock 40 of the pneumatic ejecting device 13 by rod 36 and rocker lever 39 (FIG. 2). No further mechanism is necessary for causing said inpulse of the picker.  
  During operation, the following failures might take place:  
  I. A complete short pick of gripper shuttle 14, outside shuttle box 12.  
  2. An insufficient penetration of gripper shuttle 14 into gripper shuttle box 12.  
 switch 62, the braking box 9 and picker 10 are removed from the active range of feeler 60 and it would still be possible to start the loom before removing the failure, whereupon the loom would be destroyed. The blocked control mechanism 11 reminds the attendant that the failure must first be removed, and them, by pressing hand lever 63, the control mechanism 11 is to be released. Only afterwards can the loom be started.  
  A failure as mentioned under 3) might take place, e.g., by an increased resistance of the weft 74 to be inserted. That means that the gripper shuttle 14 has a delay upon running through the shed, and at the moment of displacement of braking box 9 in the direction of arrow C is only in the position as shown in FIG. 4. Because of this, the control mechanism stops the loom but the gripper shuttle 14 still reaches its correct position. The attendant of the loom need only then release the control mechanism 11 and start the loom.  
  It follows from the above description of the control mechanism 11, that said mechanism is at rest during normal operation of the loom and further, that it does not require a special drive, because the mechanism controlling the braking box 9, or picker l0, respectively, is used.  
  The deviation in a radial direction away from the shuttle box 12 of the two arm levers 21 and 22 which at their free ends carry the braking box 9 and picker 10, is performed by turning their transverse carrier 23. The position of the transverse carrier 23 is controlled by the radial cam 32, on the circumference of which there is at least one radial recess (not shown). As soon as roller 34 of lever 33 of the transverse carrier 23 is in said recess, the said two arm levers 21 and 22 are deviated. ln order to be able to perform this deviation of two arm levers 21 and 22 further radial recesses are also formed in the cam paths 29 and 30 about a plane passing through said one recess and the common axis of rotation of radial cam 32 and control drum 28, said further radial recesses having depths which are sufficient to permit such deviation of the levers 21 and 22. It should be noted that the spring loaded lever 63 may if desired be operated manually.  
  Although the invention is illustrated and described with reference to one preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment, but is capable of numerous modifications within the scope of the appended claims.  
 What is claimed is:  
  1. A device for controlling a gripper shuttle in looms having rotary shuttle boxes on both sides thereof, each shuttle box having a guideway for the gripper shuttle. said device comprising a braking box disposed parallel with the guideway, the braking box being movable in both radial and longitudinal directions relative to said guideway, said braking box comprising a braking jaw mounted in an elastic medium and a swingable pawl with a free end, the braking box being located beside the edge of said shuttle box. and a picker with an elastic member aligned with the braking box along the direction of pick of the gripper shuttle, means mounting said picker for movement in both radial and the longitudinal direction relative to the guideway for the gripper shuttle in the shuttle box, and a feeler of a stop motion mounted within the range of said free end of the swingable pawl.  
  2. A device as claimed in claim 1, wherein the braking box comprises a plurality of springs, of which at least two springs bear against the bottom of the braking box and supporting the brakingjaw, two further aligned springs mounted above each other one of said further springs bearing against the bottom of the braking box and the other of said further springs supporting the braking jaw, and a swingable pawl having a controlled end disposed between the confronting ends of said two further springs.  
  3. A device as claimed in claim 1, wherein the braking jaw in the braking box is wedge-shaped and is arranged with its extended end in the direction of picking of the gripper shuttle into shuttle box.  
  4. A device as claimed in claim 1, wherein on the surface of the elastic member of the picker there is arranged a swingable buffer.  
  5. A device as claimed in claim 1, wherein the braking box are independently fastened at the free ends of two respective two-arm levers, of which each is arranged swingably in one plane on a transverse carrier which is swingably arranged in another plane, the opposite ends of said two two-arm levers being in engagement with respective cam paths of a control drum.  
  6. A device as claimed in claim 5, comprising a radial cam for operating the lever of the transverse carrier for said two two-arm levers, said radial cam being coupled with the control drum for the two two-arm levers.  
  7. A device as claimed in claim 6, wherein the radial cam for the lever of the transverse carrier for the two two-arm levers is provided at its active surface with at least one radial recess, and in the plane passing through said recess and the axis of rotation to both the radial cam and the control drum there are radial recesses in the cam paths of said control drum, said recesses being directly proportional in the length of their radial to those of the active surface of the recess of the radial cam.  
  8. A device as claimed in claim 1, wherein a spring loaded lever is attached to a feeler of the stop motion with attached opening contacts of an electric control circuit, said lever spring loaded lever being provided at the end thereof which cooperates with said feeler, with at least two gradual steps for the detecting position or the swung out opening position of the feeler.  
  9. A device as claimed in claim 8, wherein the spring loaded lever of the feeler of the stop motion is adapted for manual control.  
  10. A device as claimed in claim 1, wherein the braking jaw is elastic.