Coupling for rotationally connecting together the drive shafts of weave machines and weaving looms

Abstract: Coupling for connecting together the drive shafts (1001; 2001) of weave machines (2000) and weaving looms (1000), comprising at least one clutch element (21) integral with the said shaft (2001) of the weave machine (2000) and a clutch (10) integral with the shaft (1001) of the weaving loom (1000), wherein said clutch (10) comprises a disc (11; 111; 211) movable coaxially, as a result of the thrusting action of associated means (13), for engagement with said clutch element (21) integral with the shaft (2001) of the weave machine, said disc being integral with a resilient ring (12) coaxially fixed to the shaft (1001) of the weaving loom (1000), there also being provided means (15; 115) for recalling said disc (11; 111; 211) in the axial direction so as to cause disengagement thereof from the clutch element (21) integral with the shaft of the weave machine (2000).

Description: The present invention relates to a coupling for rotationally connecting together the drive shafts of weave machines and weaving looms. It is known in the art relating to the operation of weaving looms that said looms must be provided with components for conveying the weft yarn(s) and components for moving the yarns forming the warp. Said components for conveying the weft yarns may be of different types, including those of the so-called gripper type and those of the air type, depending on whether the yarn is conveyed by mechanical components, i.e. known as grippers, or by directional jets of compressed air. The components for moving the warp yarns are instead called weave machines and may be of the Jacquard or dobby type; these machines, particularly in the case of gripper looms, must be able to be operated in synchronism with the components conveying the weft yarns, so as to form the planned fabric design. It is also known that, during weaving, breakages of the weft yarn may occur and in such cases, in order to avoid having a defect in the finished piece of cloth, it is necessary to interrupt weaving and, while keeping the components conveying the weft yarn at a standstill, cause backward movement of the weave machine, undoing the fabric which has formed from the time the loom has stopped, in order to restore the continuity of the interrupted weft yarn. While, in the case of an air loom, the operation may be considered relatively simple, in the case of gripper looms it is necessary to separate the dobby from the loom and perform the backward movement thereof into the required position using an auxiliary low-speed drive component. In order to start again the weaving process it is therefore necessary to restore the coupled condition between loom and dobby, bringing them back into the relative angular position present at the time of their separation, so as to ensure the same synchronism between the relative movements occurring at the time of the interruption. For this purpose, EP 0,322,928 in the name of the same Applicant discloses, for example, dual-clutch electromagnetic couplings which allow the loom to be coupled with the dobby via the first clutch, or the two of them to be separated so as to connect, via the second clutch, the dobby to an auxiliary drive component by means of which the independent movement of the dobby itself is possible. These dual-clutch couplings, however, have considerable dimensions and weight, particularly on account of the rotor element of the clutch integral with the shaft of the weaving loom, which element must interact with the respective electromagnet in order to produce the magnetic flux field designed to recall, in the axial direction, the clutch element which is coupled with a corresponding element of the dobby clutch. Said rotor, although being axially fixed, requires however larger dimensions in order to avoid air-gap interference between rotor and electromagnet-carrying body fixed to the machine, consequently generating an increase in the costs of production and assembly of the coupling. The technical problem which is posed, therefore, is that of providing a coupling for weaving looms which overcomes these problems and allows moreover any transmission means to be used between an auxiliary motor used for slow running of the weave machine and the gearing which can be coupled to the driven shaft of said machine, in particular transmissions with cylindrical, conical, helical and similar gearings, hydraulic transmissions and the like, depending on requirements. Within the scope of this problem, a further requirement is that the coupling should consist of a small number of parts which can be easily assembled, so as to result in a lower cost, reduced maintenance and a limited cost. These technical problems are solved according to the present invention by a coupling for connecting together the drive shafts of weave machines and weaving looms, comprising at least one clutch element integral with the said shaft of the weave machine and a clutch integral with the shaft of the weaving loom, wherein said clutch comprises a disc movable coaxially, as a result of the thrusting action of associated means, for engagement with said clutch element integral with the shaft of the weave machine, there also being provided means for recalling said disc in the axial direction so as to cause disengagement of the clutch element integral with the shaft of the weave machine. Further details may be obtained from the following description of a non-limiting example of embodiment of the invention provided with reference to the accompanying drawings, in which: Figure 1 shows a cross-section along a longitudinal plane of the coupling according to the invention in the condition where it is engaged with the shaft of the weave machine of the weaving loom for normal operation; Figure 2 shows the coupling of Fig. 1 in the condition where it is disengaged from the shaft of the weave machine for slow running controlled by an auxiliary component; Figure 3 shows the clutch according to Fig. 1 in the condition where it is engaged with the shaft of the weave machine for operation of both shafts with slow running by means of an auxiliary component; Figure 4a shows a first variation of embodiment of the clutch according to the invention; Figure 4b shows a second variation of embodiment of the clutch according to the invention; Figure 4c shows a third variation of embodiment of the clutch according to the invention; Figures 5a,5b,5c show a cross-section along a longitudinal plane of the clutch according to the invention with an actuator of the hydraulic type for operation thereof, respectively in the condition for normal running, slow running of only the shaft of the weave machine, and slow running of both the shafts. Figure 6 shows an example of a variation of embodiment of the means for synchronization of the drive shaft and driven shaft. As illustrated (Figs. 1, 2, 3) the coupling according to the invention is applied to weaving machinery schematically shown with a gripper-type loom section 1000 and a weave machine section 2000 (identified below for the sake of simplicity as a dobby) which have, emerging from them, a respective drive shaft 1001 and driven shaft 2001 which must be rotationally connected together (Figs. 1 and 3) or disengaged (Fig. 2) depending on the operational requirements described below. The connection between the two said shafts 1001 and 2001 is performed by means of a coupling according to the invention, which comprises a toothed wheel 21 integral with the shaft 2001 of the weave machine 2000 and an electromagnetic operating group 10 integral with the shaft 1001 of the weaving loom 1000. The toothed wheel 21 has a set of radial teeth 21a and a set of front teeth 21b which are designed to engage with a corresponding set of front teeth 11b of a disc 11 of the clutch section 10 integral with the shaft 1001. More particularly, said disc is rigidly connected to a resilient ring 12 which in turn is fixed to the shaft 1001 by means of screws 12a or the like; thus, said ring, which is resilient in the axial direction, but rigid in the radial and circumferential direction, is able to transmit to the disc 11 the torque generated by the rotation of the shaft 1001 and at the same time allow displacement of the disc itself in the axial direction as a result of the thrusting action of springs 13 housed in associated seats 14a of a spring holder 14 keyed onto the shaft 1001. Said clutch group 10 comprises moreover an actuating element for recalling, in the axial direction, the disc 11 which, in the example according to Fig. 1, consists of a fixed annular electromagnet 15 which is integral with a fixed support part and the magnetic field of which acts by attracting the clutch disc 11 towards the shaft 1001. As can been seen, the attraction by the electromagnet occurs against the thrusting action of the springs 13 arranged between the shaft 1001 and the disc 11; thus, when the electromagnet 15 is excited, it keeps in the disengaged condition, the front teeth 21b and 11b of the wheel 21 and the disc 11, respectively, allowing separate rotation of the shafts 1001 and 2001. The disc 11 also has, mounted on it, dowels 11c arranged in non-symmetrical positions and designed to engage in corresponding holes 21c of the wheel 21 into which they are inserted, when the respective sets of front teeth 11b and 21b are engaged, thus ensuring a single position of angular coupling between the shaft 1001 and the shaft 2001. Advantageously the positions of the said dowels 11c and the corresponding holes 21c are non-symmetrical so as to allow relative engagement between wheel 21 and disc 11, with insertion of the dowels 11c into the holes 21c, in a single angular position, whereas in any other position the dowels rest on the surface of the disc, so as to keep the latter constantly perpendicular to the axis of the shafts 1001 and 2001. A similar result may be obtained by using sets of front teeth with asymmetrical teeth 3150b,3003b, as illustrated in Fig. 7. As is evident from that described above, the electromagnetic clutch 10 in the de-energized condition allows rotational connection of the shaft 1001 of the loom to the dobby shaft 2001 whereas, when energized, it must disengage the rotation of one from the other one; in this way the synchronized coupling between the loom and the dobby is maintained, even when there is no power. As schematically shown in the Figures, the ring 21 of the dobby shaft 2001 may also be operated by an auxiliary component 3000, for example a motor with a low number of revs, connected to a pinion 3001 with its axis parallel to the axis of the dobby shaft and movable axially in said direction, for engagement with/disengagement from the corresponding radial teeth 21a of the wheel 21. The coupling according to the invention operates in the following manner: in normal operating conditions for weaving (Fig. 1), the electromagnet 15 is de-energized and the auxiliary component 3000 disengaged from the toothed wheel 21 and the springs 13 therefore axially push the disc 11 so as to engage the associated front teeth 11b with the corresponding front teeth 21b of the wheel 21; as a result the shafts 1001 and 2001 are rotationally connected together, thus causing the synchronized operation of the loom and the dobby; in the event of breakage of the weft yarn (Fig. 2), the loom 1000 is stopped and the dobby shaft 2001 is disengaged from the loom shaft 1001, by means of energization of the electromagnet 15 which, overcoming the action of the springs 13, recalls the disc 11 which is separated from the wheel 21, disconnecting the shaft 2001 from the shaft 1001; by operating the actuator component 3000, the pinion 3001 meshes with the toothed wheel 21 and the drive shaft 2001 of the dobby 2000 is made to run slowly; in order to resume normal weaving operation, the shafts 1001 and 2001 must be brought back into the angular configuration corresponding to the stroke prior to stoppage; for this purpose the electromagnet 15 is de-energized so that (Fig. 3) the springs 13 push the disc 11, which is still rotationally immobile, against the wheel 21, causing the dowels 11c to make light contact with the associated front surface of the wheel itself until they are located opposite the corresponding holes 21c and penetrate into them, causing the clutch to close and locking together again the shafts 1001 and 2001 in the correct relative angular position; at the same time as the closing movement of the clutch 2000, the actuator component 3000 is deactivated, thus leaving the loom 1000 and the dobby 2000 coupled together so that weaving may be resumed. It is therefore obvious how the clutch for weaving machines according to the invention enables all the functions of conventional clutches to be achieved, but with a simplified configuration which allows all the dimensions, the weight and the overall costs of the clutch to be reduced. In addition, the elimination of the rotor also makes it possible to overcome the problems associated with the peripheral speeds of the rotor itself, which represented a constraint in the design of conventional clutches. The invention also envisages some variations of embodiment of the component parts of the coupling, as for example illustrated in Figs. 4a,4b,4c which show: A coupling (Fig. 4a) in which the disc 111 of the electromagnetic clutch has radial teeth 111a for engagement with a transmission 111d which receives movement from the main motor of the weaving loom 1000. In this configuration the shaft 1001 is integral with the dobby shaft and the disc 111 is mounted on the shaft 1001 with the intervening arrangement of bushes 1001a and is therefore idle with respect to the shaft itself. A coupling (Fig. 4b) in which the disc 211 has a set of radial teeth 211a designed for axial engagement with a corresponding set of radial teeth 21a of the toothed wheel 21. This configuration allows the thrusting force of the springs 13 and hence the dimensions of the electromagnet 15 to be reduced since the radial connection does not generate any repulsive forces in the axial direction. The configuration according to Fig. 4b also schematically shows an actuator component for slow running of the dobby shaft, which is arranged coaxially with the latter; since the actuator component is of the known type it is not described in detail. A coupling (Fig. 4c) equivalent to that of Fig. 4b, but with an actuator element for slow running of the dobby, which is parallel, and not coaxial, with the dobby shaft itself. Finally, Figures 5a,5b,5c show a coupling according to the invention with a component for causing the translatory movement of the disc 11, consisting of a hydraulic device 115 instead of an electromagnet. As illustrated, the hydraulic device 115 comprises a chamber 115a formed between a fixed cylinder 115b and a movable piston 115c which is kept pressed forwards towards the disc 11 by the action of axial springs 115d. In this way: During normal running conditions (Fig. 5a) the chamber 115a is discharged and the springs 115d push the piston 115c so that the latter does not interfere with the disc 11 which is in turn pushed so as to engage with the toothed wheel 21 by the thrust of the springs 13; in this way inteference between the rotating disc 11 and the immobile piston 115c is avoided. In the event of interruption of the weaving process and recovery of the yarn, fluid is supplied to the chamber 115a, causing the translatory movement of the piston 115c against the action of the springs 115d; this translatory movement causes the engagement of two locating surfaces 11f and 115f of the disc 11 and the piston 115c, respectively, with consequent recalling of the disc 11 which is disengaged from the toothed wheel 21, allowing operation of only the dobby shaft by means of the actuator component 3000/3001. In the case of slow running of both the loom shaft 1001 and the dobby shaft 2001 it is possible, finally, to restore the configuration of Fig. 5a, by activating, however, the actuator component 3000 which in this case causes the slow-running rotation of both the shafts. In a further version the device 115 could also be of the pneumatic type instead of the hydraulic type. It is envisaged moreover that the clutch actuating motor may be of the hydraulic and/or pneumatic type.

Claims: Coupling for rotationally connecting together the drive shafts (1001; 2001) of weave machines (2000) and weaving looms (1000), comprising at least a first clutch element (21) integral with and rigidly connected to said shaft (2001) of the weave machine (2000), said first clutch element consisting of a toothed wheel (21) that has a set of radial teeth (21a) and a set of front teeth (21b) and a second clutch (10) integral with the shaft (1001) of the weaving loom (1000), characterized in that said second clutch (10) comprises a disc (11;111;211) integral with a resilient ring (12) which in turn is coaxially fixed to the shaft (1001) of the weaving loom (1000), said disc (11;111;211) is movable coaxially, as a result of the thrusting action of associated means (13), for engagement with said clutch element (21) integral with the shaft (2001) of the weave machine, the angular synchronization between the disc (11) and the toothed wheel (21) being obtained through corresponding means (11c,21c;3150b,3003b) of both the disc (11;111;211) and the toothed wheel (21), there also being provided means (15;115) for recalling said disc (11;111;211) in the axial direction so as to cause disengagement thereof from the clutch element (21) integral with the shaft of the weave machine (2000). Coupling according to Claim 1, characterized in that said ring (12) is resilient in the axial direction and rigid in the radial and circumferential direction. Coupling according to Claim 1; characterized in that said disc (11) has radial teeth (211a) designed to engage with the radial teeth (21a) of the toothed wheel (21) of the shaft (2001) of the weave machine (2000). Coupling according to Claim 1, characterized in that said disc (11) has front teeth (11b) designed to engage with the corresponding front teeth (21b) of the toothed wheel (21). Coupling according to Claims 1 and 4, characterized in that said disc (111) has, in addition to the front teeth (11b), radial teeth (111a) designed to engage with transmission means (111d) of the motor of the weaving loom. Coupling according to Claim 1, characterized in that said means for thrusting of the disc (11) are resilient means (13). Coupling according to Claim 6, characterized in that said resilient means are springs (13) housed in corresponding seats (14a) of a spring holder (14) integral with the shaft (1001) of the loom (1000). Coupling according to Claim 1, characterized in that said means for recalling the disc (11) consist of an annular electromagnet (15) coaxial with and fixed to the weaving loom (1000). Coupling according to Claim 1, characterized in that said means for recalling the disc (11) consist of a hydraulic cylinder (115b), the piston (115c) of which is kept normally extracted by the thrusting action of resilient means (115d) arranged between cylinder (115b) and piston (115c). Coupling according to Claims 1 and 9, characterized in that said piston has a free end provided with a locating surface (115f) designed to engage with a corresponding locating surface (11f) of the disc (11). Coupling according to Claim 1, characterized in that it is provided with an auxiliary actuator component (3000) for slow-running operation of the shaft (2001) of the weave machine (2000). Coupling according to Claims 1 and 11, characterized in that said auxiliary actuator component (3000) comprises a pinion (3001) with its axis of rotation parallel to the axis of rotation of the shaft (2001) of the weave machine (2000) and designed to engage with the radial teeth (21a) of the toothed wheel (21). Coupling according to Claims 1 and 12, characterized in that said auxiliary actuator component (3000) is mounted coaxially with the shaft (2001) of the dobby machine. Coupling according to Claim 12, characterized in that said auxiliary actuator component (3000) comprises a second clutch of the electromagnetic type. Coupling according to Claim 1, characterized in that said disc (11;111;211) and said clutch element (21) have respective sets of asymmetrical front teeth (3150b,3003b) for angular synchronization of the drive shaft (1001) and the driven shaft (2001). Coupling according to Claim 1, characterized in that said disc (11;111;211) also has, mounted on it, dowels (11c) arranged in non-symmetrical positions and designed to engage in corresponding holes (21c) of the toothed wheel (21).

Inventors: BOFFELLI PIERCARLO, DEPOLI ERMINIO, BOFFELLI, PIERCARLO
Applicants: BARUFFALDI SPA, BARUFFALDI S.P.A.
Application year: 1998
Main classification: D03D51
IPC codes: D03C1, D03D51, F16D11, F16D27, F16D25