US3567354A - Apparatus for controlling the warp tension in a weaving machine - Google Patents

Abstract

THE WEAVING MACHINE HAS A BACK BEAM AROUND WHICH THE WARP IS BENT TO PROVIDE TWO WARP SPAND EXTENDING FROM THE BACK BEAM AT SUBSTANTIALLY A RIGHT ANGLE TO ONE ANOTHER. THE BACK BEAM IS MOUNTED FOR MOVEMENT IN A DIRECTION SUBSTANTIALLY PARALLEL TO ONE OF THE TWO WARP SPAND AND IS URGED IN SUCH DIRECTION BY RESILIENT MEANS TO MAINTAIN THE WARP UNDER PREDETERMINED TENSION. MECHANISM IS PROVIDED TO OPERATE IN RESPONSE TO MOVEMENT OF THE BACK BEAM IN THE OPPOSITE DIRECTION TO FEED THE WARP TOWARD THE BACK BEAM. THE IMPROVEMENT COMPRISES MECHANISM FOR RECIPROCATING THE BACK BEAM IN A PATH SUBSTANTIALLY PARALLEL TO THE OTHER OF THE TWO WARP SPANS, IN SYNCHRONISM WITH THE OPENING AND CLOSING OF THE SHED OF THE WEAVING MACHINE, TO COUNTERACT THE TENDENCY OF THE OPENING AND CLOSING OF THE SHED TO VARY THE TENSION OF THE WARP.

Description

March'Z, 1971 R-AN sEN HAL I 3,567,354

APPARATUS FOR CONTROLLING THE WARP TENSION-IN A WEAVING' MACHINE Filed Sept. 19, 1968 v m 3 Sheets-Sheet 1 March .2, T. FRANSSEN ETAL Q APPARATUS FOR CONTROLLING THE WARP TENSIONIN A WEAVING MACHINE Filed Sept 19. 1968 Sheets-Sheet 2 March 2, 1971 T FRANSSEN ETAL 3 3,567,354

APPARATUS FOR CONTROLLING THE WARP TENSION INVA WEAVING MACHINE Filed Sept. 19, 1968 3 Sheets-Sheet s United States Patent 5 Int. Cl. D03c 49/06 US. Cl. 139-408 2 Claims ABSTRACT OF THE DISCLOSURE The weaving machine has a back beam around which the warp is bent to provide two warp spans extending from the back beam at substantially a right angle to one another. The back beam is mounted for movement in a direction substantially parallel to one of the two warp spans and is urged in such direction by resilient means to maintain the warp under predetermined tension. Mechanism is provided to operate in response to movement of the back beam in the opposite direction to feed the warp toward the back beam. The improvement comprises mechanism for reciprocating the back beam in a path substantially parallel to the other of the two warp spans, in synchronism with the opening and closing of the shed of the Weaving machine, to counteract the tendency of the opening and closing of the shed to vary the tension of the warp.

BACKGROUND OF THE INVENTION The invention relates to a weaving machine provided with a movably supported back beam coopearting with an adjustable driving mechanism for the warp beam by means of a lever system as known per se in modern weaving machines.

In this known weaving machine the back beam is reciprocable over a short distance in order to prevent an increasing of the tension in the warp when the shed is entirely opened by the shaft. In such looms the movement of the back beam is used for controlling a driving mecha nism for the warp beam in order to keep the tension in the warp as constant as possible when the warp is unrolled from the warp beam. In this weaving machine use is made of a friction coupling in the driving mechanism which friction coupling is controlled by the lever system of the back beam which can be displaced against the action of a spring. The provision of a spring device as intermediate element for controlling the driving mechanism of the warp beam operates smoothly, however it is possible that the driving of the warp beam may be inaccurate and too slow when the weaving speed of the weaving machine is increased.

SUMMARY OF THE INVENTION The object of the invention is to improve such a weaving machine so that a very exact regulation of the unrolling of the warp from the warp beam is possible whereas the back beam will make its normal reciprocal movement for compensating the warp tension as a result of the opening and closing of the shed.

According to the invention this is attained in a weaving loom which is characterized in that a contact arm which makes contact with the circumferential surface of the warp beam as known per se cooperates with a continuously variable speed driving mechanism for the warp beam which has been adapted in such a manner that the warp beam is driven with a surplus of speed whereas the coupling which can be controlled by the lever system of the back beam as known per se has been inserted between the 3,567,354 Patented Mar. 2, 1971 ice" driving mechanism and the warp beam and in which the lever system together with the coupling has been adapted as a stop for the back beam in one end position. The coupling thus interrupts the driving of the warp beam and as a result of the absence of the spring mechanism the coupling can be immediately disconnected at the desired moment and as the back beam periodically makes an oscillating movement as a result of its driving synchronously with the opening and closing of the shed the coupling will make successive short strokes in which depending on the average tension in the warp the coupling connects the driving shaft with the driven shaft of the driving mechanism for the warp beam during a small period of its stroke. As a result of the adjustment in the surplus of the driving speed and by the adjustment of the correct stroke of the coupling with its concerning lever system for driving of the warp beam for unwinding the warp, an exact regulation is obtained.

It is to be remarked that the provision of a continuously variable speed driving mechanism for the warp beam is already known. Such a mechanism in the shape of a V-belt gear is controlled immediately by movement of the back beam owing to which the regulation of the unwinding of the warp is not exact and slow.

The practical embodiment of a weaving machine in which the back beam has been movably supported according the invention is characterized in that the back beam has been supported in bearings which can move in the longitudinal direction of rocker arms, which bearings are supported on pushing rods which can make a reciprocable axial movement depending on the movement of the reed, whereas the rocker arms rest against a lever by the tension of the warp which lever forms a part of the lever system of the coupling in the driving mechanism. One special object of the invention is to adapt the driving mechanism for the warp beam in the loom in such a manner that the coupling which cooperates with the lever system is double acting in which a part of the coupling cooperating with the driving shaft has been adapted as a friction coupling and the part cooperating with the driven shaft has been adapted as a claw coupling. The claws of the coupling which cooperates with the lever system in termesh with the claws of the part of the coupling mounted on the driven shaft when the weaving machine is in normal operation, whereas the part of the coupling cooperating with the lever system has been mounted in such a manner that it can freely rotate around the driving shaft and can engage with its friction surface against a friction surface which has been fastened to the driving shaft.

By the provision of such a double acting claw coupling it is possible to reverse the driving of the warp beam, e.g. when the weaving machine is to be set back in order to be able to correct a weaving defect.

An approximate regulation of the driving of the warp is possible because the driving shaft is provided with a continuously variable speed drive in which the adjusting part has been connected to a contact arm which rests on the circumferential surface of the warp beam owing to which when the diameter of the warp beam decreases a higher rate of speed can be given to the driving shaft.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram in which the driving mechanisms for the warp beam, a back beam, a chest beam and a cloth beam have been indicated together with two lever systems which cooperate with the back beam;

FIG. 2 is a side view partly in section of a part of the driving mechanism for the warp beam showing a part of the lever system cooperating with the coupling and FIG. 3 shows a further side view, partly in section of the driving mechanism for the warp beam near the step- 3 less regulator cooperating with the arm resting on the circumference of the warp beam.

Some main parts of the weaving machine are shown in the diagram of FIG. 1 in which the warp beam 1 together with the Warp 2 rigged thereon, the back beam 3, the Weaving shafts A, the reed B, the chest beam C, the sand beam D and the cloth beam B have been indicated.

The warp beam is driven by means of a separate driving mechanism in such a manner that independently of the diameter of the warp beam 1 the tension in the warp 2 remains always the same. The back beam 3 has been movably supported in gaps 4 in rocker arms 6 which are pivoted at 5. The bearings of the back beam in the gaps 4 rest on the ends of pushing rods 8 which at their lower ends are supported on lever 10 pivotably supported at 9. By means of couplings 11, 12, 13 and bell crank levers 14 and 15 the lever 10 has been connected to an arm 17 of the rotatable shaft 16 of the reed. When the reed B rocks around its shaft 16 the arm 17 makes also a rocking movement owing to which the pushing rods 8 are subjected to a reciprocal axial movement in a path substantially parallel to the warp span which extends between the warp beam 1 and the back beam 3 and is substantially at a right angle to the warp span which extends from the back beam 3 to the chest beam C. When the reed B has a retracted position, thus a position in which the shed as a result of the movement of the weaving shafts A is entirely open the pushing rods will take their lowermost position, that is to say a position in which the back beam 3 has its nearest position to the pivot point 5 of the rocker arms 6. By this displacement of the back beam in the gaps 4 the warp threads 2 are somewhat released in such an amount as the increasing of tension in the warp as a result of the opening of the shed, to counteract the tendency of the' opening and closing of the shed to vary the tension of the warp. As the gaps 4 run parallel to the longitudinal direction of the rocker arms 6 the movement of the back beam 3 by the action of the pushing rods 8 will not have any component in the rocking direction of the arms 6 that is to say no inconvenient side effects in the rocking movement of the arms 6 are caused because the bearings of the back beam 3 are mounted in the gaps 4 for sliding movement in a direction substantially radial to the axis 5 about which the supporting rocker arms 6 are pivoted. The position of the rocker arms 6 depends only on the sum of the tensions in the warpthreads 2. As a result of the tension in the warp the rocker arms 6 rest against the free end of a lever 19 which has been pivotally supported at 18. The lever 19 is further connected to a lever 21 by means of a link 20. The lever 21 has been pivotally supported at 22. Further the lever 21 has been connected to a bell crank lever 25 by means of a link 23. The lever 25 has been pivotally supported at 24 and cooperates with a movable part 26 of the coupling which is a part of the driving mechanism for the warp beam.

A spring has been connected to the free end of the lever 21 and the spring action can be adjusted in order to keep the entire lever system between the rocker arms 6 and the coupling 26 under proper tension and to urge the back beam in a direction substantially parallel to the warp span that extends from the back beam 3 to the chest beam C so as to maintain the warp under predetermined tension. When now the tension in the warp 2 increases the back beam 3 will be moved in a direction opposite to that which the back beam is urged by the spring acting through the levers 21 and 19, as the rocker arms 6 will swing around the pivot 5 and the rocker arms 6 will displace the lever 19 owing to which the coupling 26 will be engaged to feed the warp toward the back beam. That is to say the friction surface of the coupling 26 comes into contact against the friction surface 28 of the driving shaft 29 and the rotation of the shaft 29 will be transferred to the driven shaft 42 of the driving mechanism and the beam 1 will be driven as a result of the connection of the coupling 26*. When the warp beam 1 is driven the tension in the warp 4 2 will immediately decrease and the back beam together with the rocker arms 6 will return as a result of the action of the spring of the lever 21. Thus the lever 19 pushes the rocker arms 6 back. If desired the action on the rocker arms 6 can be supportedby an auxiliary spring.

As the amount of driving the warp beam 1 must be less when the beam is fully loaded than when the beam is nearly empty the operation of the coupling 26 would be more frequent when the warp beam 1 is more unrolled. In order to obtain a good unrolling of the warp the period during which the coupling 26 is engaged when the warp beam is partly unrolled would have to be larger than with an entirely loaded beam. This could be disadvantageous because extremes in tensions of the warp could arise. In order to avoid this drawback the driving shaft 29 will have different speeds of rotation depending on the diameter of the warp beam. For this purpose a contact arm 31 known per se has been provided. The operation of such a contact arm in varying the driving speed of the driving shaft 29 will be described later.

The coupling 26 which has been diagrammatically indicated in FIG. 1 has been shown in FIG. 2 together with the friction surface 28, the driving shaft 29, the driven shaft 42 and the lever 25 for actuating the coupling 26. The coupling 26 has a central part that fits slidably around the shaft 29. If desired an especial side bearing can be provided. Further the coupling 26 can freely rotate around the shaft 29. A pressure spring 32 has been situated around the shaft 29 between the coupling 26 and the friction surface 28 which has the shape of a disc. The friction surface 28 has a tight fit around the driving shaft 29 and is prevented from rotation by means of a key 33. A circumferential groove 37 has been formed by means of a circumferential flange 34 and an endplate 35 which has been connected to the coupling part 26 by means of screws. A pin 38 of the lever 25 projects into the circumferential groove 37. The side of the endplate 35 which is remote from the groove 37 has been provided with a crown of teeth 39 which forms the claws of a claw coupling. The teeth 39 cooperate with a similar crown of teeth at an end surface of a claw coupling 41 provided with a circumferential groove 46. The claw coupling 41 is prevented from rotating however, it can move in an axial direction on the driven shaft 42 of the driving mechanism. In order to prevent the coupling 41 for rotating around the shaft 42 a key 43 has been mounted on the shaft 42. By means of pin 44 of a lever 46 which can rock around the shaft 45 and which pin projects into a circumferential groove 40 of the coupling 41 this coupling can be caused to contact the crown of teeth 39 of the coupling 26. The coupling 41 has been adapted as a stop for the coupling 26. The lever 46 has been connected to a pushing rod 47 whose length can be adjusted by means of a turnbuckle 48. The pushing rod 47 has been connected to a control device eg an electromagnet which can be energized in such a manner that the coupling 41 intermeshes with the crown of teeth 39 or will be entirely free from the teeth. When the coupling 41, which is double acting, is free from the teeth 39 of the coupling 26 the teeth 50 of the coupling 41 intermesh with with the teeth 51 of a gear Wheel 52 which can freely rotate around the shaft 42. The gear wheel 52 however, cannot move in an axial direction. Further the driven shaft 42 has been coupled with a gear box 53 which has been adapted as a reduction gear. A pinion (not shown) of the gear box 53 intermeshes with a gear wheel which is connected to the warp beam in a known manner. This gear wheel has been diagrammatically shown with a dash dotted line 54.

When the coupling 41 has been released from the coupling 26 the driving shaft 29 has been disconnected from the driven shaft 42 also when the friction surface 55 of the coupling 26 rests against the friction surface 23. As has been stated above in this condition the teeth 50 of the coupling 41 intermesh with the teeth 51 of the gear wheel 52. This is possible when the electromagnet 49 has been energized. The teeth of the gear wheel 52 intermesh with the teeth of a pinion 56 mounted on the shaft of an electric motor 57.

When the electric motor 57 is energized the gear wheel 52 will be driven and the rotation is transferred to the driven shaft 42 via the coupling 41. The direction of the motor 57 is such that the shaft 42 is driven in a direction opposed to the direction of rotation of the shaft 29. Under these circumstances the direction of rotation of the warp beam is reversed and the warp will be wound up. This facilitates the correction of weaving defects when some wefts are to be removed. Up to now the warp beam has to be reversed by hand and this so called back weaving can be regulated from the operation panel of the weaving machine.

As has been stated above the speed of the driving shaft 29 can be regulated by means of a contact arm 31 which rests against the circumference of the warp beam.

In order to perform such a regulation the shaft 29 has been provided with a gear wheel 58 which intermeshes with a long pinion 59. This pinion 59 has been mounted on a shaft of a contact wheel 60 which rests against the end surface of a friction disc 61. The friction disc 61 is driven by a rotating part of the weaving machine e.g. by the main shaft 62 of the weaving machine and a chain 63 as indicated by a dash dotted line in FIG. 3.

The contact wheel has been mounted in ears 64 and 65 of a bushing 66 which can pivot and move in an axial direction around the driving shaft 29. The ears 64 and 65 have been positioned in such a manner with respect to the bushing 66 that the contact wheel presses against the friction disc 61 as a result of the reaction between the teeth of the pinion 59 and the gear wheel 58. The bushing 66 has been provided with a tooth rack 67 which intermeshes with a tooth sector 68.

The tooth sector 68 has been mounted on a rotatably supported shaft 69 which has been further provided with a tooth sector 70. The tooth sector 70 meshes into a tooth rack of a driving rod 71 which engages by means of a pin 72 in a guiding slot situated in a plate 75 of the contact arm 31. For clearness sake the circumference of the warp beam has been indicated by a dash dotted line 76. The roller 78 of the contact arm 31 makes immediate contact with the packet of warp threads on the warp. When now the warp threads are to be drawn from the warp beam the circumference of the warp beam will be decreased and the contact arm 31 will follow and rotate around its shaft 79. The guiding slot possesses a part 73a which has been concentrically situated around the shaft 79. This part of the slot has been provided in order to be able to lift the contact arm 31 from the entirely loaded beam without moving the contact wheel 60 in a radial direction on the friction disc 61 as a result of moving of the contact arm 31. Lifting the contact arm 31 facilitates placing of a new warp beam. The part 7312 of the guiding slot is approximately straight and is used when the contact arm 31 follows the decreasing diameter of the warp beam as a result of which the contact arm 31 will be displaced. As a result of such displacement the bushing 66 moves in an axial direction with respect to the driving shaft 29 and the contact wheel will be displaced on the friction disc 61. By the large rate of transmission between the pinion 59 on the shaft of the contact wheel 60 and the gear wheel 58 only slight pressure of the contact wheel 60 against the friction disc 61 is sufficient for a good driving of the warp beam. When the contact wheel 60 moves outwardly in a radial direction on the friction disc 61 the driving shaft 29 will obtain a higher rotation speed. The rotation is only transmitted to the driven shaft 42 when the friction surface 55 of the coupling 26 presses against the friction surface 28 and the teeth of the coupling 41 intermesh with the teeth 39 of the coupling 26. As the operation of the coupling 26 as a result of the position of the back beam 3 with its rocker arm 6 is intermittently performed it is desired that the driving shaft 29 have an excess of speed. The coupling 26 cooperates also with a stationary friction surface 28a, owing to which the coupling 26 will be stopped when it is released from the friction surface 28.

A contact wheel 60 and a friction disc 61 have been described as an example of a continuously variable speed driving mechanism. Another driving mechanism e.g. the driving mechanism shown in FIG. 1 can be used also. This driving mechanism which can be considered as a unit has been provided with an operation lever and a pushing rod 71 connected to the contact arm 31. The pushing rod 71 and the operating lever 70 in FIG. 1 can be considered as the same parts as the sliding rod 71 and the sector 70 in FIG. 3, as they are just elements for transferring the movement of the arm 31 to the contact transmission.

We claim:

1. Apparatus for controlling the warp tension in a weaving machine having a back beam around which the warp is bent to provide two Warp spans extending from the back beam at substantially a right angle to one another, the back beam being mounted for movement in a path substantially parallel to one of the two warp spans, comprising resilient means for urging the back beam in such path, in a direction to maintain the warp under tension, and mechanism which operates, in response to movement of the back beam in the opposite direction, to feed the warp toward the back beam, wherein the improvement comprises driving mechanism for reciprocating the back beam in a path substantially parallel to the other of the two warp spans, in synchronism with the opening and closing of the shed of the weaving machine, to counteract the tendency of the opening and closing of the shed to vary the tension of the warp.

2. Apparatus according to claim 1 wherein the back beam is rotatably supported in bearings that are mounted, in a support which is pivotable about a fixed axis, for sliding movement in a direction substantially radial to such axis, and the reciprocating mechanism is connected to reciprocate the bearings in their slidable mounting.

References Cited UNITED STATES PATENTS 1,667,221 4/1928 Sakamoto 139l08 2,609,006 9/1952 Lord 139108 2,812,780 11/1957 Sakamoto 139108 2,819,734- l/1958 Pfarrwaller 1391 10 2,914,092 ll/ 1959 Clentimack 139108 3,125,128 3/1964 Pfarrwaller 1391 15 FOREIGN PATENTS 861,345 2/1961 Great Britain 139-108 JAMES KEE CHI, Primary Examiner

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