US3810493A

US3810493A - Tension regulating apparatus for loom

Info

Publication number: US3810493A
Application number: US00192973A
Authority: US
Inventors: Y Mizuno
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1970-10-30
Filing date: 1971-10-27
Publication date: 1974-05-14
Anticipated expiration: 1991-05-14
Also published as: CS177070B2

Abstract

An improved apparatus for regulating a tension in warp yarns fed from a yarn beam of a loom is disclosed, which is adapted to regulate a torque on the yarn beam in accordance with the variation in the overall diameter of the roll of the yarns on the beam throughout the operation of the loom thereby to maintain the tension in the warps being unwound from the beam. The apparatus uses a weight which is in engagement with a threaded bar in a manner to vary the torque on the yarn beam. The threaded bar is mounted on a support structure which tends to turn relative to the yarn beam as the beam rotates. Such rotational deviation of the support beam is remedied by a position adjusting mechanism which is driven in synchronism with the loom so that the support means is returned to its initial position to transmit a proper torque to the rotating yarn beam.

Description

tinited States Patent [191 Mizuno TENSION REGULATING APPARATUS FOR [73] Assignee: Nissan Motor Company, Limited,

Yokohama City, Japan [22] Filed: Oct. 27, 1971 [21] Appl. No.: 192,973

[30] Foreign Application Priority Data Oct. 30, 1970 Japan 45-108588[U] Nov. 4, 1970 Japan 1 45-96577 Dec. 23, 1970 Japan 1 45-116260 Dec. 23, 1970 Japan 45- 116261 52 us. Cl. 139/110 [51] Int. Cl. D03d 49/06 [58]. Field of Search 139/97, 100, 110, 109,

I [56] References Cited UNITED STATES PATENTS 2,819,734 1/1958 Pfarrwaller 139/110 1,698,497 1/1929 Gunning 139/110 2,699,051 1/1955 Noe 139/110 X 767,937 8/1904 Gossett et a1... 139/110 495,766 4/1893 Wilby 139/110 2,707,380 5/1955 Ebert 66/86 A 2,654,236 10/1953 Clentimack 139/110 X FOREIGN PATENTS OR APPLICATIONS 1,099,725 1/1968 Great Britain 139/110 Primary Examiner-James Kee Chi [57] ABSTRACT An improved apparatus for regulating a tension in warp yarns fed from a yarn beam of a loom is disclosed, which is adapted to regulate a torque on the yarn beam in accordance with the variation in the overall diameter of the roll of the yarns on the beam throughout the operation of the loom thereby to mainsynchronism with the loom so that the support means is returned to its initial position to transmit a proper torque to the rotating yarn beam.

24 Claims, 17 Drawing Figures PATENTEBHAY 4 97 3.810.493

sum 01 or 11 INVENTOR vum 0 M12 NO BY ATTOR E PATENTED MAY 14 I974 sum 02 or 11 INVENTOR Yuma MIzuNo m ATO E PATENTEB m 14 m4 sum 03 w n INVENTOR M T T A PATENTEMY 14 4914 saw on or 11 INVENTOR VUKI ZU VO BY )A ATTOR EY PATENTEMY 14 m4 3.810.493

' sum usnr11 INVENTOR VUKIO MIZuA/D ATTOR Y PATENTEDHAY 14 i974 3.810.493

sum us (If n INVENTOR -Yllkl0 MI ATTORN PATENTEUIIAU4IBT4 3310.493

sum 070f11 Fig. 9

INVENTOR WK! 0 MIzu/v 0 ATTORNE PATENTEUIIAY 14 m4 sum 08 or 11 INVENTOR W KI M/Z /v 0 BY M 5 4 ATTORNE minnow 14 :97:

saw as w w INVENTOR Yu M l 0 MI Z HIV 0 BY 2N 2 ATTOR EY PATENTEDIAY 14 m4 saw mm H INVENTOR Y k/0 MlZU/VO BY ATTORN Y INVENTOR YHKIO MILLl/VO BY ATTOR EY TENSION REGULATING APPARATUS FOR LOOM This invention relates generally to looms and particularly to a tension regulating apparatus for use in the looms. Such apparatus is adapted to regulate a tension in warp yarns to be passed from a yarn beam to healds through a back-rest roller.

A tension regulating apparatus is known which uses a weight in association with the yarn beam for the purpose of regulating a torque to be applied to the rotating yarn beam from which the warp yarns are passed to the backrest roller. As the warp yarns are unwound from the yarn beam, the outside diameter of the roll of the yarns carried on the yarn beam decreases gradually so that it is required to have the torque on the yarn beam varied or reduced as the operation of the loo'm proceeds. A typical priorart tension regulating apparatus is constructed in a manner to detect the variation in the outside diameter of the roll of the yarns on the beam so as to move the weight in conformity to the variation in the outside diameter of the roll of the yarn. The apparatus of this character uses an ingeniously constructed driving mechanism which is costly and intricate and which usually involves a difficulty in properly regulating the torque on the yarn beam and accordingly the tension in the yarn throughout the varying operational conditions of the loom. Apparently, this is because of the fact that the torque exerted by the weight is indirectly transmitted to the yarn beam.

An object of this invention is, therefore, to provide an improved tension regulating apparatus which is economical to manufacture and which is capable of properly regulating the torque on the yarn beam in strict accordance with the variation in the diameter of the roll of the yarns on the beam and with any other operational variables of the loom.

The tension regulating apparatus achieving this object generally includes a support structure which is movably positioned relative to the yarn beam, a threaded bar supported on this support structure and extending substantially at a right angle to the-rotary shaft of the yarn beam, the threaded bar being rotatable about its axis; biasing means engaging with the threaded bar for biasing the bar so as to exert a torque on the yarn beam, the biasing means being movable on the yarn beam, the biasing means being movable on the threaded bar to continuously reduce the torque on the yarn beam as the threaded bar is rotated about its axis during operation, gearing means associated with the yarn beam and the threaded bar so that the threaded bar is rotated at a speed substantially proportional to the speed of rotation of the yarn beam, clutch means which is disposed between the gearing means and the threaded bar in a manner that the threaded bar is usually disconnected from the gearing means, and clutch control means which is associated with the back-rest roller for detecting a tension in the warp yarns through sensing the position of the back-rest roller relative to the yarn beam, the control means being connected to clutch means for causing the clutch means to be coupled when the tension in the warp yarns reaches a predetermined magnitude.

The support structure and the threaded bar supported thereon tend to turn about an axis of the gearing means rotating with the yarn beam. This will make its rather difficult to properly maintain the torque on the yarn beam and accordingly to maintain constant the tension in the warp yarns being fed from the beam.

It is, therefore, another object of this invention to provide a tension regulating apparatus having, in addition to the above described basic construction, a position adjusting mechanism which includes a worm wheel rotatable with the yarn beam and the aforesaid gearing means, a worm meshing with the worm wheel and rotatably supported on the support structureand driving means for driving the worm substantially in synchronism with the loom when the worm wheel is driven by the yarn beam at a speed higher than the speed of rotation of the worm during operation.

In the drawings:

FIG. 1 is a perspective view showing an overall construction of a preferred embodiment of the tension regulating apparatus according to this invention;

FIG. 2 is a vertical sectional view showing, on an enlarged scale and partly in side elevation, a detailed construction of the apparatus illustrated in FIG.- 1;

FIG. 3 is a top end view of a clutch and gear arrangement forming part of the apparatus shown in FIGS. 1 and 2;

FIG. 4 is a perspective view showing another preferred embodiment of the apparatus according to this invention, the shown apparatus having features additional to the apparatus of FIGS. 1 to 3;

FIG. 5 is a vertical sectional view showing, partly in side elevation, a detailed construction of the apparatus shown in FIG. 4;

FIG. 6 is a sectional view showing an example of a' power transfer unit of a position adjusting mechanism forming part of the apparatus shown in FIGS. 4 and 5;

FIG. 7 is a sectional view showing, partly in side elevation, another form of the position adjusting mechanism;

FIG. 8 is a top end view of a power transfer unit forming part of the position adjusting mechanism of FIG. 7;

struction principle of a driving unit of the mechanism shown in FIG. 12;

FIG. 14 is a view similar to FIG. 13 but now illus- I trates a preferred construction principle of another form of the drivingunit;

FIG. 15 is a perspective view showing still another preferred embodiment of the tension regulating apparatus in accordance with the invention;

FIG. 16 is a side elevational view showing, partly in section, the apparatus illustrated in FIG. 15; and

FIG. 17 is a'side elevational view showing essential parts of still another preferred embodiment of the tension regulating apparatus according to this invention.

Referring to the drawings, first to FIGS. 1 to 3, the

apparatus of this invention constitutes part of a loom which includes a yarn beam 20 and a back-rest roller 21 positioned in parallel to the yarn beam. The yarn beam 20 has a pair of flanges one of which is indicated at a and carries thereon warp yarns 22, as seen in FIG. 1. The yarn beam 20 is rotated about a shaft 23 so that the warp yarns 22 are unwound therefrom. The warp yarn 22 are passed to healds (not shown) of the loom through the back-rest roller 21, as customary. The tension regulating apparatus according to this invention is generallyv intended to regulate the tension in the warp yarns 22 thus fed from the yarn beam 20.

The tension regulating apparatus of this nature includes a spur gear 24 mounted on the shaft 23 so as to be rotatable with the yarn beam 20. This spur gear 24 meshes with a pinion 25 which is mounted on a shaft 26 extending substantially in parallel to the shaft 23 of the yarn beam. The shaft 26 is rotatably supported by a support structure 27 through an aperture (not numbered) formed therein and carries at its leading end a helical gear 28 which is positioned outside of an upright wall (not numbered) of the support structure. A threaded bar 29 having an extension 29a (FIG. 2) is supported at this extension on a block 30 and at the opposite end by a block 31. The block 30 is fast on or forms part of the support structure 27. Designated by reference numeral 32 is a stop member securing the toothed rack 29 to the bracket 31. The threaded bar 29 is positioned substantially at a right angle to the shaft 26 and is usually associated with a guide rod 33 extending below and substantially in parallel to the toothed rack. This guide rod 33 is secured at both ends to the

blocks

30 and 31 by means of bolts 34 and 35, respectively. A guide piece 36 engages with the threaded bar a 29 through an internally threaded bore 36a formed therein and is slidably supported on the guide rod 33 through a finished bore 36b which is also formed in the guide piece. An adjustable weight 37 depends from this guide piece 36 through a rod 38. This weight 37 may be replaced, if preferred, with suitable resilient means such as a spring which is seated on or connected to any structure member of the loom.

The threaded bar 29 has mounted on its extension 29a a helical rack 39 which is rotatable around this extension and which meshes with the helical gear 28 on the shaft 26. A torque exerted by the weight 37 is thus transmitted to the yarn beam 20 through the threaded bar 29, helical rack 39, helical gear 28, pinion 25 and gear 24 in this sequence. As clearly seen in FIG. 3, the helical rack 39 has formed at its outer end a clutch half 39a through which it is engageable with an opposed clutch half 40 which is axially slidably mounted on the extension 29a of the threaded bar. The clutch half 40 may be splined to the extension 29a or otherwise axially movably supported on the extension 290 through a key 41 as illustrated in FIG. 2. This clutch half 40 is thus rotatable with the threaded bar 29 through the cooperating clutch flange 39a. A disc 42 having an operating knob 42a is secured to an end portion of the extension 29a by a bolt 43 so that the threaded bar 29 can be manually rotated about its axis.

The tension regulating apparatus further includes a mechanism which is adapted for detecting the tension in the warp yarns 22 passing on the back-rest roller 21. This tension detecting mechanism includes a tension detecting bifurcated lever 44 having a pair of angularly spaced

arms

44a and 44b. The lever 44 is pivotally supported on any part of the frame structure of the loom through a fulcrum pin 45. One arm 44a of this bifurcated lever 44 is pivotally connected to a shaft 21a on which the back-rest roller 21 is rotatably mounted and the other arm 44b is connected to a tension spring 46 which is secured to the frame structure of the loom in a manner to bias the lever 44 to rotate in a direction to raise the back-rest roller 21, viz., clockwise of the drawing. A connecting rod 47 is pivotally connected to an end portion of the bifurcated lever 44 opposite to the

arms

44a and 44b and depends therefrom the toward the support structure 27 which is previously mentioned. This connecting rod 47 is associated with a clutch actuating lever 48 having a pair of

arms

48a and 48b. One arm 48a of this clutch actuating lever 48 is directed generally at a right angle to the control rod 47 and has formed therein an aperture (not numbered) through which the connecting rod slidably extends. The other arm 48b of the clutch actuating lever projects downwardly and is pivotally connected to the axially movable clutch half 40 through a pin 49, as seen in FIG. 3. The clutch actuating lever 48 is pivotally connected to the frame structure of the loom through a shaft 50. The connecting rod 47, furthermore, has mounted or integrally formed thereon a pair of flanges 51 and 51' which are spaced from both faces of the arm 48a of the clutch actuating lever. A pair of compression springs 52 and 52' are seated on between the flange 51 and the upper face of the arm 48a and the other between the flange 51' and the lower face of the arm 48a, as seen in FIG. 2.

Before the operation starts, the adjustable weight 37 which has been moved toward the block 30 during the preceding operation should be moved to the block 31 by manually turning the disc 42 at the knob 42a so that a maximum torque is applied to the yarn beam 20 from the weight 37. When the operation is commenced, the gear 24 rotates with the yarn beam 20 in the direction of arrow A and drives the pinion 25 and helical gear 28 to turn. The helical rack 39, which is rotatable around the extension 29a of the toothed rack, is thus driven by the helical gear 28. As the operation proceeds, the diameter of the roll of the yarns on the beam 20 decreases and concurrently the tension in the yarns unwound from the beam increases progressively so that it becomes necessary to reduce the torque on the yarn beam, as previously noted.

As the tension in the warp yarns 22 increases, the

back-rest roller 21 is urged downwardly so that the ten sion detecting bifurcated lever 44 is turned counterclockwise about the fulcrum pin 45 against the action of the spring 46, causing the control rod 47 to be raised from its initial position. The clutch actuating lever 48 with arm 48a pressed on both sides by the compression springs 52 and 52' is accordingly forced to turn counter-clockwise about the shaft 50. This causes the arm 48b of the clutch actuating lever 48 to axially move the clutch half 40 toward the rotating helical rack 39 until it engages with the cooperating clutch half 39a. The helical rack 39 is now coupled with the clutch half 40 with the result that the threaded bar 29 starts to totate with the clutch half 40. The guide piece 36 consequently slides on the threaded bar 29 away from the block 31 whereby the weight 37 is moved toward the opposite block 30 and the torque on the beam 20 and accordingly the tension in the warp yarns 22 are reduced. The tension detecting bifurcated lever '44 now rotates clockwise by the aid of the tension spring 46 to permit the control rod 47 to lower so that the clutch actuating lever 48 is rotated clockwise to cause the clutch half 40 to be disengaged from the rotating helical rack 39. The threaded bar 29 thus ceases to rotate and accordingly the weight 37 stops to move. The tension regulating apparatus repeats these actions during operation of the loom so as to maintain constant the tension in the warp yarns being fed from the beam.

When, now, the beam and spur gear 24 are rotated in the direction of arrow A as indicated in FIG. 1, the threaded bar 29 and the support structure 27 in its entirety tend to turn about the shaft 26 in the direction of arrow B, namely, in the opposite direction to the direction of rotation of the beam 20. This will invite a difficulty in properly maintaining the torque exerted on the yarn beam and it is, therefore, desired that the apparatus shown in FIGS. 1 to 3 be equipped with a position adjusting mechanism which is adapted to compensate for a rotational or angular deviation of the. support structure 27 and the threaded bar 29, a preferred form such mechanism being shown in FIGS. 4 to 6.

Referring concurrently to FIGS. 4 and 6, the position adjusting mechanism includes a worm wheel 53 which is rotatable withthe shaft 26 supporting the gears and 28 at its opposite ends. This worm wheel 53 meshes with a worm 54 secured to an elongated rotary shaft 55 through a key 56. This rotary shaft 55 extends substantially in parallel to the threaded bar 29 and the associated guide rod 33 and is rotatably supported on a pair of bearings 57 and 57' which are mounted on the support structure 27. A disc 58 having an operating knob 58a is secured to one end portion of the shaft 55 through a bolt 59 and a first or driven bevel gear 60 is secured to the other end portion of the shaft through a bolt 61, as seen in FIG. 5. This bevel gear 60 is in mesh with a second or intermediate bevel gear 62 which is rotatable on a shaft 63 secured to the support structure 27.

The intermediate bevel gear 62 operatively interconnects the worm gear arrangement to a power transfer unit which forms part of the position adjusting mechanism, a detailed construction of such power transfer unit being illustrated in FIG. 5. The power transfer unit, as shown, is generally made up of driving means 64 which is adapted to be driven in synchronism with the loom and driven means 65 which is adapted to be driven by the driving means 64 as to drive the worm gear arrangement through the intermediate bevel gear 62.

The driving means 64 is shown to include a stationary flange or bracket 66 which is fast on the frame structure of the loom and which has a bored boss 66a and a stationary shaft 66b received therein. A rotary driving disc member 67 having a boss 67a is rotatably and axially slidably mounted on the shaft 66b through a bush 68. A sleeve 69 having a collar portion 69a is fast on the outer peripheral wall of the boss 67a of the rotary driving disc member 67 through a key 70. A bearing 71 is mounted on the sleeve 69 and is axially held in position by means of the collar portion 69a of the sleeve.

A sprocket wheel 72 is secured to an outer peripheral wall of the collar portion 69a of the sleeve. Thus, the rotary driving disc member 67, sleeve 69 and sprocket wheel 72 are all rotatable together about the shaft 66b. The sprocket wheel 72 is associated with a driving sprocket wheel 72 through a chain 73, as seen in FIG. 4. The driving sprocket wheel 72 is driven from the loom per se. Between the rotary driving disc member 67 and the collar portion 69a of the sleeve is seated a 6 compression spring 74 urges the rotary driving disc member 67 away from the bracket 66.

The driven means 65, on the other hand, is shown to include a rotary driven disc member 75 which is supported on a rotary shaft 76 through a bolt 77. This shaft 76 is positioned in an approximately upright position and substantially at a right angle to the shaft 66b of the bracket 66 of the driving means 64, as shown. The rotary driven disc member 75 of the driven means 65 is in frictional contact at its circumferential edge with an outer face of the rotary driving disc member 67 preferably through a frictional member 78. The shaft 76 is rotatably supported intermediately by a bearing 79 and at its lower end portion by a bearing 80. The bearing 79 is supported on or forms part of a supporting arm 81 which extends from the stationary bracket 66 of the driving means 64, while the bearing 80 is supported on or integral with the support structure 27. A third or driving bevel gear 82 is mounted at the lower end of the shaft 76 and meshes with the second or intermediate bevel gear'62 supported on the shaft 63 extending substantially at a right angle to the shaft 76.

When,'now, the driving sprocket 72' is driven with the loom in operation, then the sprocket 72 of the driving means 64 is driven through the-chain 73, thereby rotating the driving rotary disc member 67 through the sleeve 69 and key 70. The rotary driving disc member 67, in turn, drives the rotary driven disc member 75 of the driven means 65 through the frictional member 78. It is, in this instance, apparent that the speed of rotation of the rotary driven disc member 75 depends upon the radial distance between the center of the disc member 67 and the contact point between the two rotary disc members, namely, upon the position of the rotary driven disc member 75 relative to the center of the rotary driving disc member 67. The rotary driven disc member 75 now drives the third or driving bevel gear 82 through the shaft 76 and this bevel gear, in turn, drives the first or driven bevel gear through the second or intermediate bevel gear 62. The rotational force is in this manner transmitted to the worm 54 through the shaft 55 extending from the bevel gear 60 so as to finally drive the worm wheel 53, whereby the rotational or angular deviation of the support structure .27 in the direction of arrow B can be remedied or compensated for by the rotation of the worm wheel 53.

If, now, the yarn beam 20 is rotated at an increased speed and accordignly the worm wheel 53 is driven at a higher speed than the worm 54, then it will happen that the support structure 27 is turned in the direction of the arrow B as indicated in FIG. 4. This causes the shaft 76 of the driven means to be raised from its initial position with the result that the rotary driven disc member is brought into contact with the driving rotary disc member 67 at a point remoter from the center of the disc member 67. The rotary driven disc member 75 and consequently the worm 54 are thus driven at the higher speed so that the support structure 27 is urged in the direction opposite to the direction of arrow B. The shaft 76 of the driven means 65 is in this manner lowered to its initial position so that the worm 54 is now It is to be noted that the frictional contact between the rotary driving and driven

disc members

67 and 75, respectively, is not impaired by the upward and downward movements of the'shaft 76 because the shaft 76 is axially slidably supported by the bearing 79 on the supporting arm 81 and because the rotary driving disc member 67 is constantly urged toward the driven rotary disc member 75 by the action of the compression spring 74.

A modified example of the position adjusting mechanism applicable to the apparatus illustrated in FIGS. 1 to 3 is shown in FIGS. 7 to 11. As seen in FIG. 7, the modified position adjusting mechanism uses a worm gear arrangement which is essentially similar to the counterpart of the mechanism shown in FIG. 5, including the worm wheel 53, worm 54, shaft 55, key 56, bearings 57 and 57' and disc 58. This worm gear arrangement is connected to a driving unit throughdriven, intermediate and driving

bevel gear

60, 62 and 82, respectively. The modified position adjusting mechanism has a driving unit which is generally made up of driving means 83 driven in synchronism with the loom and driven means 84 driven by this driving means, as indicated in FIGS. 8 and 9.

The driving means 83 includes a stationary bracket 85 which is secured to the frame structure of the loom by means of bolts 86. The bracket 85 has a boss 85a in which a shaft 85b is securely received through a bolt 87. A sleeve 88 is rotatably supported on the outer peripheral wall of the boss 85a of this bracket and a pair of supporting

arms

89 and 89 having a bearing 90 formed at their leading ends extend from the sleeve 88 as best seen in FIG. 8. A rotary driving member 91 having a bevel gear 91a and a sprocket wheel 91b on both ends is rotatably mounted on the shaft 85b of the bracket 85. This sprocket wheel 91b is driven by a cooperating sprocket wheel (not shown) through a chain 92 (FIG. 7) in a manner similar to the chain and sprocket arrangement of the mechanism previously described. The rotary driving member 91 engages with a rotary driven member 93 having a bevel gear 93a which meshes with the bevel gear 91a of the rotary driving member 91. This rotary driven member 93 is rotatably received in the bearing 90 on the ends of the supporting arms 89 and 89' and is held in position by a collar 94 and a bolt 95. The rotary driven member 93 has formed at its bottom a helical cam portion 96 having a generally vertical edge 96a. The driven means 84, on the other hand, includes a generally cylindrical member 97 which is secured by a bolt 98 to a shaft 99 rotatably and axially slidably extending through an axial bore 93b in the rotary driven member 93 substantially at a right angle to the shaft 85b of the bracket 85. The cylindrical member 97 has formed thereon an abutment 97a which is engageable with the helical cam portion 96 when the shaft 99 is raised through the axial bore 93b in the rotary member 93. The shaft 99 supports at its lower end the bevel gear 82, similarly to the shaft 76 of the mechanism shown in FIG. 5.

When, now, the sprocket wheel 91b of the rotary driving member 91 is driven by the cooperating driving sprocket wheel (not shown) through the chain 92 in synchronism with the loom, then the bevel gear 91a drives the rotary driven member 93 through the bevel gear 93a thereof so that the helical cam portion 96 of the driven member 93 is rotated in the direction of arrow C in FIG. 10. If, in this condition, the support structure 27 is turned about the shaft 26 in the direction of arrow A as indicated in FIG. 1 or 4, the shaft 99 connected to the support structure through the bevel gears 82, 62 and and the worm gear arrangement is raised from its initial position until the abutment 97a of the cylindrical member 97 is brought into engagement with the helical cam portion 96 of the driving means 83. The cylindrical member 97 is consequently driven for rotation with the shaft 99 so that the worm wheel 53 is driven through the bevel gears 82, 62 and 60. The support structure 27 in this manner turned in the direction opposite to the direction of arrow B indicated in FIG. 4. The rotational or angular deviation of the support structure 27 thus being remedied, the shaft 99 is permitted to lower through the axial bore 93b in the rotary driven member 93 so as to cause the cylindrical member 97 to be disengaged from the helical cam portion 96 of rotary driven member 93. The shaft 99 now stops rotation and the support structure 27 tends to turn about the shaft 26 for a second time. The support structure 27 is at all times maintained in a balanced condition through repetition of these actions.

The helical cam portion 96 of the rotary driven member 93 may preferably be formed in a manner that the generally vertical edge 96a thereof be offset at an appreciable angle from the axial direction of the cam member so as to facilitate the abutment 97a of the cylindrical member 97 to engage with and disengage from the this helical cam portion 96.

It is to be noted that, although the shaft 99 tends to sway about the shaft b of the bracket 85 when the support structure 27 turns, such swaying motion of the shaft 99 can be cancelled by the rotation of the sleeve 88 around the boss 85a of the bracket 85.

FIG. 11 illustrates a modification of the cam member of the driving unit of the construction shown in FIGS. 8 and 9. This modified cam member, designated by numeral 100, has a downwardly tapered rod 100a depending from a mount 1001) which is fastened to the shaft 99.

Still another example of the position adjusting mechanism for the apparatus according to this invention is now illustrated in FIG. 12. The mechanism herein shown includes a worm gear arrangement which is entirely similar to that previously described and which is associated with the driven and

intermediate bevel gears

60 and 62 shown in FIGS. 5 and 7. Difierent from the driving unit shown in FIG. 5 or 7, the driving unit of the mechanism shown in FIG. 12 includes

rollers

101 and 102 as driving and driven means, respectively. The driving roller 101 is driven by a chain and sprocket arrangement which includes spaced driving and driven

sprocket wheels

103 and 104, respectively and a chain 105 passed thereon. The driving sprocket wheel 103 is rotatable on a shaft 106 which is secured to the frame structureof the loom and is driven in synchronism with the loom during operation. The driven sprocket wheel 104, on the other hand, is rotatable on a shaft 107 which is also secured to the frame structure of the loom. The driving roller 101 is mounted on the shaft 107 of the driven sprocket wheel 104 so as to be rotatable therewith. The driving roller 102 is rotatably mounted on the shaft 63 of the intermediate bevel gear 62 so as to be rotatable with the intermediate bevel gear. The

rollers

101 and 102 are externally tangent to each other as at 108.

Inoperation, the driving sprocket wheel 103 is driven about its shaft 106 in synchronism with the loom so that the driven sprocket wheel 104 is driven about its shaft 107 through the chain 105. The driving roller 101 is consequently driven and this in turn causes the driven roller 102 to rotate together with the intermediate bevel gear 62 about the shaft 63. The worm wheel 53 is rotated so that the support structure 27 which has been turned in the direction of the arrow A as indicated in FIG. 4 is in this manner permitted to resume its initial position.

In order to avoid production of a twisting torque about the shaft 26 as a result of the driving engagement between the two

rollers

101 and 102 as at the point 108, the driving roller 101 may be positioned in such a manner that, as shown in FIG. 13, the combined force F resulting from a reaction A produced at point 108 and directed to the center of the driven roller 102 and a tangential frictional force B at port 108 passes through the center of the shaft 26.

FIG. 14 illustrates a modification of the driving unit shown in FIG. 12. This modified driving unit is essentially similar to the driving unit of FIG. 12, except in that the driven means is in the form of a cylindrical roller which is designated by numeral 102 and that the driving roller 101' is internally tangent to the driven roller 102' as at point 108. In this instance, the driving roller 101 may preferably be positioned in such a manner that the combined force F resulting from a reaction A produced at point 108' and directed away from the center of the driven roller and a tangential frictional force B at the point 108 passes through the center of the shaft 26.

Still another embodiment of the tensionregulating apparatus in accordance with this invention is illustrated in FIGS. and 16, in which the control means for the clutch on the threaded bar and the driving means for the worm of the position adjusting mechanism are now constructed to be operative in an electrical fashion. The electrically operating clutch control means includes, as shown, switch means 109 which is responsive to a change in the position of the back-rest roller 21 relative to the yarn beam 20. This switch means 109 is made up of a tension detecting lever 110 having opposed arms 110a and 11% and pivotally connected as at 111 to any structural member of the loom. The arm 110a of this lever 110 is releasably engaged with the back-rest roller 21 through a suitable connecting member 112 as illustrated so that the lever 110 as, a whole is subject to a pressure exerted by the back-rest roller 21 with the warp yarns 22 being passed thereon. Suitable spring means such as a tension spring 113 is connected to the other arm 11012 of the lever 110 whereby the lever 110 is biased to turn clockwise of the drawing against the pressure exerted thereon by the back-rest roller 21. The tension spring 113 is seated on any structural member of the loom as at 114. The switch means 109 further comprises a switch element 115 which is adapted to be closed or opened depending upon the angular position of the lever 110 relative thereto. This switch element v115 may be constructed 1 in any desired manner insofar as it is capable of responding to the motion of the lever 110. Examples of such switch element may be a microswitch or a contactless relay. The switch element 115 is connected through anelectric line 116 to a clutch control unit 117 which, as a whole, is fast on the support structure 27.

The clutch control unit 117 has a clutch actuating lever 117a which extends toward the extension 29a of the threaded bar 29 and engages with the axially movable clutch half which, in the embodiment illustrated, is located next to the block 30 on the threaded bar 29. This clutchactuating lever 117a usually stays close to this block 30 so that the clutch half 40 remains disengaged from the cooperating clutch half 39a on the threaded bar 29. The clutch control unit 117 may be constructed as desired and, as such, no detailed description of the same will be herein incorporated. One example of such unit is the one utilizing a rotary solenoid device.

Where, thus, the switch element'115 is of the normally open characteristics, the clutch control unit 117 is actuated when the switch element 115 is closed with the back-rest roller 21 lowered excessively due tothe increased tension inthe warp yarns 22 being passed thereon so that the tension detecting lever 110 is forced to turn counter-clockwise of the drawing against the action of the tension spring 113. The clutch control unit 117 being actuated in this manner, the clutch lever 117a is moved away from the block 30 so as to press upon the-axially movable clutch half 40. The clutch half 40 is consequently caused to engage with the cooperating clutch half 39a. The threaded bar 29 is now rotated with the clutch half 39a which is being rotated in synchronism with' the yarn beam through the spiral gears 39 and 28.

The driving means for the worm 54 meshing with the worm wheel 53 of the position adjusting mechanism includes a belt and pulley arrangement 118 which is driven by a motor 119; The motor 119 is connected through an electric line 120 to a switch element 121 which is constructed to be responsive to change in the angular positions or counter-clockwise rotation about the shaft 26 of the support structure 27 and accordingly the worm wheel 53. When, thus, thesupport structure 27 is brought into engagement with the switch element 121, then this switch element is actuated. The belt and v pulley arrangement 118 includes

pulleys

122 and 123 which are respectively rotatable with

shafts

124 and 125 of the motor 119 and worm 54 and a belting 126 passed on these

pulleys

122 and 123.

When, thus, the switch element 121 is closed (if the switch element is of the normally open characteristics) structure 27 to rotate clockwise about the shaft 26 so as to permit the yarn beam 20 to receive a proper torque and as a result the tension in the warp yarns 22 is properly adjusted.

In lieu of the switch element 121 which acts as an onoff switch and the motor 119 which operates on an a.c. power, a voltage generator adapted to produce a d.c.' voltage in accordance with the amount of angular displacement of the support structure 27 and a d.c. motor which is connected to this voltage generator to be energized by the voltage supplied therefrom.

A still modified form of the tension regulating apparatus of this invention is illustrated in FIG. 17. As shown, a brake disc 127 is mounted on the stationary shaft 23 of the yarn beam 20 and a brake band 128 is wrapped around this brake disc. The brake band 128 is secured at one end to the frame structure of the loom as at 128a and at the other end to an extension 27a formed on the support structure 27 as at l28b. When, during operation, the support structure 27 is urged clockwise with the threaded bar 29 force downwardly by the adjustable weight 37, then the brake band 128 tightly presses upon the brake disc 127 with the result that a considerably great torque is imparted to the rotating yarn beam 20.

As the operation of the loom proceeds and the wieght 37 approaches the block 30, the brake band 128 becomes gradually slackened to cause the torque on the yarn beam to be alleviated and to consequently reduce the tension in the warp yarns 22 from the beam to a proper extent.

It will now be appreciated from the foregoing description that, in spite of its simple and economical construction, the tension regulating apparatus according to this invention is useful in maintaining constant the tension in the warp yarns passed from the yarn beam. The position adjusting mechanism which may form part of such apparatus is initiated into action by the very motion of the yarn beam per se and in relation to the variation in the tension in the yarns being fed. Thus, it is unnecessary to use costly and intricate detecting and control mechanisms for the regulation of the tension in the yarns. The apparatus according to this invention is therefore expected to suit the purpose of fabricating a uniformly woven cloth of excellent quality.

What is claimed is: 1. A tension regulating apparatus in a loom having a yarn beam rotatably mounted for delivering warp yarns to healds via a back-rest roller, comprising a support structure movably positioned relative to said yarn beam, a threaded bar rotatably mounted on said support structure and extending substantially at right angles to the axis of said yarn beam, gearing means associated with and driven by said yarn beam and associated with and driving said threaded bar, biasing means engaging with said threaded bar for biasing same to exert a torque on said yarn beam, said biasing means being movable along the threaded bar to reduce said torque on the yarn beam as the threaded bar is rotated, clutch means disposed between said gearing means and said threaded bar, said clutch means connecting the gearing means and the threaded bar when the clutch means is coupled and disconnecting the gearing means and the threaded bar when the clutch means is uncoupled, and clutch control means associated with said back-rest roller for detecting a tension in said warp yarns by sensing the position of the back-rest roller relative to said yarn beam and operativcly connected to said clutch means, said clutch control means causing the clutch means to be coupled when said tension in the warp yarns reaches a predetermined magnitude.

2. A tension regulating apparatus according to claim I, in which said gearing means comprises a driving gear driven by said yarn beam and a driven gear rotatably mounted on said threaded bar and in mesh with said driving gear whereby the threaded bar is rotated about its axis substantially perpendicular to the axis of said yarn beam when said clutch means is in a coupled condition.

3. A tension regulating apparatus according to claim 1, in which said clutch means comprises a clutch half formed on said gearing means and an opposed clutch halfwhich is axially movably mounted on an extension of said threaded bar and which is usually held by said clutch control means in a position to be uncoupled from said clutch half on said gearing means and moved to be coupled with said clutch half on the gearing means when the clutch control means detects the tension in said warp yarns reaching said predetermined magnitude.

4. A tension regulating apparatus according to claim 1, in which said biasing means comprises a guide piece having formed therein an internally threaded bore through which said guide piece is movable on the threaded bar' and a weight depending from said guide piece.

5. A tension regulating apparatus according to claim 1, in which said clutch control means comprises a ten sion detecting lever pivotally supported on a fulcrum pin, and connected to shaft of said back-rest roller for responding to change in the position of the back-rest roller relative to said yarn beam and to spring means which is operative to bias said control means to a position to hold said clutch means in an uncoupled condition, a generally vertically extending connecting rod which is pivotally connected at its upper end to said tension detecting lever, said tension detecting lever being turned against the action of said spring means in a direction to raise said connecting rod when said backrest roller is moved with said tension in the warp yarns increased, and a clutch actuating lever having a pair of angularly spaced arms one of which is directed substantially at a right anglevto said connecting rod and supported thereon through resilient support means and the other of which is directed toward said clutch means for causing the clutch means to be coupled when said tension detecting lever is turned against said action of said spring means.

6. A tension regulating apparatus according to claim 1, in which said clutch control means comprises switch means responsive to changes in the position of said back-rest roller relative to said yarn beam and a clutch control unit associated with said clutch means and electrically connected to said switch means, said clutch control unit being operable to cause said clutch means to be coupled when said switch means is actuated responsive to the tension said warp yarns increased to said predetermined magnitude. I

7. A tension regulating apparatus according to claim 6, in which said switch means comprises a tension detecting lever pivotally connected to any structural member of said loom and associated at one end with said back-rest roller, spring means biasing said tension detecting lever to pivotally turn against a pressure applied thereto by said back-rest roller, and a switch element positioned relative to the other end of said tension detecting lever and actuated as said lever is moved responsive to a change in the relative position of said back-rest roller.

8. A tension regulating apparatus according to claim 1, further comprising a position adjusting mechanism which includes a worm wheel rotatable with said yarn beam and said gearing means, a worm meshing with said worm wheel and rotatably supported on said support structure and driving means for rotating said worm when said support structure is rotated relative to said yarn beam whereby said worm wheel is driven to urge the support structure to rotate in an opposite direction.

9. A tension regulating apparatus according to claim 8, in which said driving means comprises a first bevel gear rotatable with said worm, a second bevel gear meshing with said first bevel gear, and a drive unit which is in driving engagement with said second bevel gear and which is driven by said loom.

10. A tension regualting apparatus according to claim 9, in which said drive unit comprises a stationary bracket having a fixed shaft, a rotary driving member which is rotatable on said fixed shaft, a sprocket wheel rotatable with said rotary driving member and driven by said loom, spring means biasing said rotary driving member away from said stationary bracket, a rotary driven member which is circumferentially in frictional contact withan outer face of said rotary driving member a rotary shaft supporting said rotary driven member, and a bevel gear mounted on the last named rotary shaft and meshing with said second bevel gear.

11. A tension regulating apparatus according to claim 9, in which said drive unit comprises a stationary bracket having a fixed shaft, a rotary driving member rotatable on said fixed shaft, said rotary driving member including a sprocket wheel which is driven by said loom and a bevel gear rotatable with said sprocket wheel, a rotary driven member rotatably supported around an axially movable shaft which is axially movable in said rotary driven member and whichis directed substantially at a right angle to said fixed shaft, said rotary driven member comprising a bevel gear meshing with said bevel gear on said rotary driving member and rotatable about said axially movable shaft, said bevel gear on said rotary driven member having formed thereon a cam portion, a generally cylindrical member mounted on said axially movable shaft and'having an abutment which is engageable with said cam portion when said axially movable shaft is raised through said rotary driven member, and a bevel gear mounted on said axially movable shaft and meshing with said second bevel gear.

12. A tension regulating apparatus according to claim 11, in which said rotary driven member is supported on a bearing formed at leading end portions of a pair of supporting arms extending from said stationary bracket.

13. A tension regulating apparatus according to claim 11, in which said cam portion has a helical configuration having a substantially longitudinally extending edge.-

. 14. A tension regulating apparatus according to claim 13, in which said longitudinally extending edge is substantially offset from an axial direction.

15. A tension regulating apparatus according to claim 11, in which said cam portion includes a forwardly tapered rod.

16. A tension regulating apparatus according to claim 9, in which said drive unit includes a driving roller which is driven by said loom and a driven roller which is in contact with said driving roller and rotatable with said second bevel gear.

17. A tension regulating apparatus according to claim 16, in which said driving roller is externally tangent to said driven roller. 7

18. A tension regulating apparatus according to claim 16, in which said driving roller is internally tan gent to said driven roller.

19. A tension regulating apparatus according to claim 16, in which said driving roller is located in a manner that a combined forced resulting from a reaction exerted at a contact point between the driving and driven rollers and directed perpendicular to the circumference of said driven roller at said contact point and a tangential frictional force at said contact point passes through an axis about which said support structure is movable relative to said yarn beam.

20. A tension regulating apparatus according to claim 8, in which said driving means comprises switch means responsive to change in the angular position of said support structure relative to said yarn beam and actuated when the support structure is moved exces sively, a motor connected to said switch means and energized when actuated from said'switch means, and a belt and pulley arrangement drivingly interconnecting said motor and said worm.

21. A tension regulating apparatus according to claim 8, in which said driving means comprises a voltage generator producing a dc voltage substantially proportional to change in the angular position of said support structure relative to said yarn beam, a dc. motor connected to said voltage generator for being energized with said dc. voltage, and a belt and pulley arrangement driving by interconnecting said motor and said worm.

22. A tension regulating apparatus according to claim 1, further comprising a brake discwhich is attached to a stationary shaft on which said yarn beam is rotatable and a brake band wrapped around said brake disc, said brake band being connected at one end to any structural member of said loom and at the other to an extension of said support structure for applying a gradually decreasing torque to said yarn beam as said biasing means exerts a decreasing torque on said threaded bar.

23. A tension regulating apparatus according to claim 2, in which said clutch means comprises a clutch half formed on said gearing means'and an opposed clutch half which is axially movably mounted on an extension of said threaded bar and is usually held by said clutch control means in a position to be uncoupled from said clutch half on said gearing means and moved so as to be coupled with said clutch half on the gearing means when the clutch control means detects the tension in said warp yarns reaching said predetermined magnitude. 1

24. A tension regulating apparatus according to claim 23, in which said biasing means comprises a guide piece having formed therein an internally threaded bore through which said guide piece is movable on the threaded bar and a weight depending from said guide piece.

Claims

1. A tension regulating apparatus in a loom having a yarn beam rotatably mounted for delivering warp yarns to healds via a backrest roller, comprising a support structure movably positioned relative to said yarn beam, a threaded bar rotatably mounted on said support structure and extending substantially at right angles to the axis of said yarn beam, gearing means associated with and driven by said yarn beam and associated with and driving said threaded bar, biasing means engaging with said threaded bar for biasing same to exert a torque on said yarn beam, said biasing means being movable along the threaded bar to reduce said torque on the yarn beam as the threaded bar is rotated, clutch means disposed between said gearing means and said threaded bar, said clutch means connecting the gearing means and the threaded bar when the clutch means is coupled and disconnecting the gearing means and the threaded bar when the clutch means is uncoupled, and clutch control means associated with said backrest roller for detecting a tension in said warp yarns by sensing the position of the back-rest roller relative to said yarn beam and operatively connected to said clutch means, said clutch control means causing the clutch means to be coupled when said tension in the warp yarns reaches a predetermined magnitude.

2. A tension regulating apparatus according to claim 1, in which said gearing means comprises a driving gear driven by said yarn beam and a driven gear rotatably mounted on said threaded bar and in mesh with said driving gear whereby the threaded bar is rotated about its axis substantially perpendicular to the axis of said yarn beam when said clutch means is in a coupled condition.

3. A tension regulating apparAtus according to claim 1, in which said clutch means comprises a clutch half formed on said gearing means and an opposed clutch half which is axially movably mounted on an extension of said threaded bar and which is usually held by said clutch control means in a position to be uncoupled from said clutch half on said gearing means and moved to be coupled with said clutch half on the gearing means when the clutch control means detects the tension in said warp yarns reaching said predetermined magnitude.

4. A tension regulating apparatus according to claim 1, in which said biasing means comprises a guide piece having formed therein an internally threaded bore through which said guide piece is movable on the threaded bar and a weight depending from said guide piece.

5. A tension regulating apparatus according to claim 1, in which said clutch control means comprises a tension detecting lever pivotally supported on a fulcrum pin, and connected to shaft of said back-rest roller for responding to change in the position of the back-rest roller relative to said yarn beam and to spring means which is operative to bias said control means to a position to hold said clutch means in an uncoupled condition, a generally vertically extending connecting rod which is pivotally connected at its upper end to said tension detecting lever, said tension detecting lever being turned against the action of said spring means in a direction to raise said connecting rod when said back-rest roller is moved with said tension in the warp yarns increased, and a clutch actuating lever having a pair of angularly spaced arms one of which is directed substantially at a right angle to said connecting rod and supported thereon through resilient support means and the other of which is directed toward said clutch means for causing the clutch means to be coupled when said tension detecting lever is turned against said action of said spring means.

6. A tension regulating apparatus according to claim 1, in which said clutch control means comprises switch means responsive to changes in the position of said back-rest roller relative to said yarn beam and a clutch control unit associated with said clutch means and electrically connected to said switch means, said clutch control unit being operable to cause said clutch means to be coupled when said switch means is actuated responsive to the tension said warp yarns increased to said predetermined magnitude.

10. A tension regualting apparatus according to claim 9, in which said drive unit comprises a stationary bracket having a fixed shaft, a rotary driving member which is rotatable on said fixed shaft, a sprocket wheel rotatabLe with said rotary driving member and driven by said loom, spring means biasing said rotary driving member away from said stationary bracket, a rotary driven member which is circumferentially in frictional contact with an outer face of said rotary driving member a rotary shaft supporting said rotary driven member, and a bevel gear mounted on the last named rotary shaft and meshing with said second bevel gear.

11. A tension regulating apparatus according to claim 9, in which said drive unit comprises a stationary bracket having a fixed shaft, a rotary driving member rotatable on said fixed shaft, said rotary driving member including a sprocket wheel which is driven by said loom and a bevel gear rotatable with said sprocket wheel, a rotary driven member rotatably supported around an axially movable shaft which is axially movable in said rotary driven member and which is directed substantially at a right angle to said fixed shaft, said rotary driven member comprising a bevel gear meshing with said bevel gear on said rotary driving member and rotatable about said axially movable shaft, said bevel gear on said rotary driven member having formed thereon a cam portion, a generally cylindrical member mounted on said axially movable shaft and having an abutment which is engageable with said cam portion when said axially movable shaft is raised through said rotary driven member, and a bevel gear mounted on said axially movable shaft and meshing with said second bevel gear.

13. A tension regulating apparatus according to claim 11, in which said cam portion has a helical configuration having a substantially longitudinally extending edge.

14. A tension regulating apparatus according to claim 13, in which said longitudinally extending edge is substantially offset from an axial direction.

17. A tension regulating apparatus according to claim 16, in which said driving roller is externally tangent to said driven roller.

18. A tension regulating apparatus according to claim 16, in which said driving roller is internally tangent to said driven roller.

20. A tension regulating apparatus according to claim 8, in which said driving means comprises switch means responsive to change in the angular position of said support structure relative to said yarn beam and actuated when the support structure is moved excessively, a motor connected to said switch means and energized when actuated from said switch means, and a belt and pulley arrangement drivingly interconnecting said motor and said worm.

21. A tension regulating apparatus according to claim 8, in which said driving means comprises a voltage generator producing a d.c. voltage substantially proportional to change in the angular position of said support structure relative to said yarn beam, a d.c. motor connected to said voltage generator for being energized with said d.c. voltage, and a belt and pulley arrangement driving by interconnecting said motor and said worm.

22. A tension regulating apparatus according to claim 1, further comprising a brake disc which is attached to a stationary shaft on which said yarn beam is rotatable and a brake band wrapped around said brake disc, said brake band being connected at one end to any structural member of said loom and at the other to an extension of said support structure for applying a gradually decreasing torque to said yarn beam as said biasing means exerts a decreasing torque on said threaded bar.

23. A tension regulating apparatus according to claim 2, in which said clutch means comprises a clutch half formed on said gearing means and an opposed clutch half which is axially movably mounted on an extension of said threaded bar and is usually held by said clutch control means in a position to be uncoupled from said clutch half on said gearing means and moved so as to be coupled with said clutch half on the gearing means when the clutch control means detects the tension in said warp yarns reaching said predetermined magnitude.