Coupling for rotationally connecting actuating shafts of weave machines and weaving looms

Abstract

 Coupling for rotationally connecting actuating shafts (1001; 2001) of weave machines (1000) and weaving looms (2000), comprising at least one first clutch element (21) integral with the said shaft (1001) of the weave machine (1000) and a second clutch element (10) integral with the shaft (2001) of the weaving loom (2000), said second clutch element (10) comprising a disk (11) movable coaxially, owing to the thrusting action of associated means (13), for engagement with said first clutch element (21), there also being provided fixed means (15;15a) for recalling said disk (11) in the axial direction in order to cause disengagement thereof from the first clutch element (21) integral with the shaft of the weave machine (1000), said disk (11) having first means (11b) and second means (lid) for engagement with corresponding means (21b) of the first clutch element (21) and with means (15d) of said second clutch element (15), respectively.

Description

[0001] The present invention relates to a coupling for rotationally connecting actuating shafts of weave machines and weaving looms. It is known in the technical sector relating to the manufacture of weaving looms that said looms must be provided with members for conveying the yarn(s) forming the weft and members for moving the yarns forming the warp.

[0002] Said members for conveying the weft yarns may be of different types, including those of the so-called gripper type.

[0003] The members 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 actuated in synchronism with the members for conveying the weft yarns, in order to form the intended weave design.

[0004] It is also known that there exists the possibility, during the course of weaving, that breakages of the weft yarn may occur and, in such cases, in order to prevent there being a defect in the finished cloth, it is required to stop the weaving process and, keeping the weft-yarn conveying members still, reverse the direction of operation of the weave machine, thereby undoing the fabric formed at the moment of stoppage of the loom, in order to restore the continuity of interrupted weft yarn.

[0005] In the case of gripper looms, it is necessary to separate the dobby from the loom and perform the reverse movement thereof by means of an auxiliary, low-speed, drive member into the desired position.

[0006] In order to start the weaving process again, it is therefore necessary to restore the connection between loom and dobby, arranging again the said machines in the same relative angular position in which they were in at the moment of separation, so as to ensure the same synchronism between the corresponding movements occurring at the moment of interruption.

[0007] For this purpose, EP 0,877,111 in the name of the same proprietor discloses, for example, a coupling for connecting actuating 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 part integral with the shaft of the weaving loom, said clutch part comprising a disk movable coaxially, owing to the thrusting action of associated means, for engagement with said clutch element integral with the shaft of the weave machine, said disk being integral with a resilient ring coaxially constrained to the shaft of the weaving loom, there also being provided means for recalling said disk in the axial direction in order to cause disengagement thereof from the clutch element integral with the shaft of the weave machine.

[0008] With the use of the latest types of actuating motor it has nevertheless been possible to arrange the main actuating motor so as to be directly connected to the dobby shaft which may therefore be directly actuated by the said motor both during normal operation and during slow running/reverse operation for location of the shed.

[0009] Although with this configuration it is possible to eliminate substantially the slow-running auxiliary motor and the brake/clutch assembly previously located between drive shaft and loom, nevertheless the loom assembly remains without an element which ensures with certainty stoppage thereof during disengagement for location of the shed.

[0010] This means that the loom, and therefore the grippers, may stop in any position which is not predetermined and not in synchronism with the drive shaft, which may give rise to serious problems should the position of the grippers still be within the warp.

[0011] The technical problem which is posed, therefore, is that of providing a coupling for weaving looms which, upon stoppage of the motor, ensures safe and reliable corresponding stoppage of the driven shaft of the loom in predetermined angular positions and that of ensuring that this position is maintained with certainty during the whole of the shed-locating step until correct synchronism with the drive shaft has been restored.

[0012] Within the context of this problem a further requirement is that the coupling should consist of a small number of parts which can be easily assembled so that it has a low weight, low cost and reduced maintenance requirements.

[0013] These technical problems are solved according to the present invention by a coupling for rotationally connecting actuating shafts of weave machines and weaving looms, comprising at least one first clutch element integral with the said shaft of the weave machine and a second clutch element integral with the shaft of the weaving loom, said second clutch element comprising a disk movable coaxially, owing to the thrusting action of associated means, for engagement with said first clutch element integral with the shaft of the weave machine, there also being provided fixed means for recalling said disk in the axial direction in order to cause disengagement thereof from the first clutch element, said disk having first means and second means for engagement with corresponding means of the first clutch element and with means of said second clutch element, respectively.

[0014] 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 engaged with the shaft of the weave machine of the loom for normal operation;
• Figure 2 shows the coupling of Fig. 1 in the condition at the start of disengagement from the drive shaft of the weave machine for slow operation; and
• Figure 3 shows the coupling of Fig. 1 in the condition totally disengaged from the weave shaft.

[0015] As illustrated (Fig. 1), the coupling according to the invention is fitted to weaving looms schematically shown with a gripper loom part 2000 and a weave machine part 1000 (for the sake of simplicity referred to below as "dobby") which are respectively connected to a driven shaft 2001 and to a drive shaft 1001 of a single actuating motor M, which must be suitably rotationally connected together (Fig. 1) or disengaged (Fig. 3) depending on the operational requirements described below.

[0016] The connection between the two shafts 1001 and 2001 is performed by means of a coupling 20 according to the invention which is arranged between them and which comprises a toothed wheel 21 integral with the shaft 1001 of the weave machine 1000 and an electromagnet actuating assembly integral with the shaft 2001 of the weaving loom 2000.

[0017] The toothed wheel 21 has a first set of front teeth 21b able to mesh with corresponding set of front teeth 11b of a disk 11 of the clutch part 10 integral with the shaft 2001.

[0018] In greater detail, said disk 11 is integrally joined to a resilient ring 12 in turn constrained to the shaft 2001 by means of screws 12a or the like; in this way said ring, which is resilient in the axial direction, but rigid in the radial and circumferential direction, is able to transmit to the disk 11 the torque produced by the rotation of the shaft 2001 and at the same time allow the displacement of the disk itself in the axial direction, owing to the thrusting action of springs 13 housed in associated seats 14a of a spring carrier 14 keyed onto the shaft 2001.

[0019] Said clutch assembly 10 also comprises an actuating element for recalling the disk 11 in the axial direction, said element in the example of Fig. 1 consisting of a fixed annular electromagnet 15 which is integral with a fixed support part 15a and the magnetic field of which acts by attracting the clutch disk 11 towards the shaft 2001.

[0020] As can be seen, the attraction exerted by the electromagnet opposes the thrusting action of the springs 13 arranged between the shaft 2001 and the disk 11; in this way, when the electromagnet 15 is excited, it keeps, in the disengaged condition, the front teeth 21b and 11b of the wheel 21 and the disk 11, respectively, allowing the independent rotation of the shafts 1001 and 2001.

[0021] The ring 11 is also provided with a second set of front teeth 11a located opposite the first set and able to engage with a corresponding set of front teeth 15d of the electromagnetic actuating assembly 15. The ring 11 is also equipped with lugs 11c which are arranged in asymmetrical positions and are able to combine with corresponding holes 21c in the wheel 21 into which they are inserted, when the respective sets of front teeth 11b and 21b are engaged, thus ensuring a precise relative angular coupling position of the shaft 1001 and the shaft 2001.

[0022] Advantageously the positions of said lugs 11c and the corresponding holes 21c are asymmetrical so as to allow the relative engagement between wheel 21 and ring 11 with insertion of the lugs 11c in the holes 21c, in a specific angular position, while in any other position the lugs rest against the surface of the disk 11 so as to keep the latter constantly perpendicular to the axis of the shafts 1001 and 2001.

[0023] Advantageously said angular synchronism may also be obtained by means of a suitable configuration of the two sets of front teeth 11b and 21b for the driving part and 11d, 15d for the driven part.

[0024] As can be seen from that described above, the electromagnetic clutch 10 allows, in the non-excited condition, the rotational connection of the shaft 1001 of the motor M and the dobby 1000 to the shaft 2001 of the loom, while, when excited, it must disengage the rotation of one shaft from the other; in this way the synchronised connection between the loom and the dobby is maintained also when there is no power.

[0025] The operating principle of the coupling according to the invention is as follows:

• during normal operating conditions for weaving (Fig. 1), the electromagnet 15 is in the non-excited state and the springs 13 axially push the disk 11, freeing the front teeth 11d and 15d and causing the meshing of the associated front teeth 11b with the corresponding front teeth 21b of the wheel 21; consequently, the shafts 1001 and 2001 are connected together. rotationally, thus ensuring synchronous operation of the loom and the dobby;
• in the event of breakage of the weft yarn, the motor M is stopped and the shaft 2001 of the loom is disengaged by means of excitation of the electromagnet 15 which, overcoming the action of the springs 13, recalls the disk 11 which starts to separate from the wheel 21;
• during this stage (Fig. 2), the ring 11 remains simultaneously constrained both to the rim 21, by means of the respective sets of teeth 11b, 21b which are not yet completely disengaged, and to the fixed operating assembly 15 by means of meshing - already started - of the front teeth 11d with the fixed teeth 15d.
  In this way the driven shaft 2001 is never left entirely uncontrolled and continues to remain correctly synchronised with the drive shaft 1001, thus allowing the machine to be stopped with the grippers in the correct position outside of the warp;
• once the disengagement stage has been completed (Fig. 3), the actuating shaft 1001 of the dobby 2000 is freed from engagement with the shaft 2001 and, by actuating the motor M with a reduced number of revolutions, it is possible to start slow running/reverse operation in order to locate the lost shed;
• to resume normal weaving, the shafts 1001 and 2001 must be brought back into the angular position existing at the operating stroke prior to stoppage; for this purpose, the electromagnet 15 is de-energised so that (Fig. 3) the springs 13 push the disk 11, which is still fixed rotationally, against the wheel 21, causing the studs 11c to rub lightly against the associated front surface of the wheel itself until they are located opposite the corresponding holes 21c and penetrate inside them, causing closure of the clutch and ensuring the rigid connection again, in the correct relative angular position, of the shafts 1001 and 2001; at the same time as the closing movement of the clutch, the motor M is brought back into the normal rotating condition, thus leaving the loom 1000 and the dobby 2000 connected ready to start weaving again.

[0026] Alternatively the synchronism may be achieved by means of an angular control system of the electronic type consisting for example of an encoder coaxial with the shaft 1001.

[0027] It is therefore obvious how, with the clutch for weaving looms according to the invention, it is possible to achieve all the operational features of conventional clutches, but with a simplified configuration which allows a reduction in the volume, weight and overall cost of the clutch, while ensuring that the relative synchronism between the drive shaft and the driven shaft is maintained during disengagement of the coupling and that the driven shaft 2001 is kept safely stopped for the whole of the time during which it is disengaged from the drive shaft.

[0028] According to the invention, some variations in the design of the component parts of the coupling are also envisaged; more particularly, it is envisaged that the front teeth 11d and 15d of the disk 11 and of the fixed part 15a of the electromagnet may be replaced by several simple elements such as, for example, pins and holes (not shown) which may also be machined with greater tolerances compared to the teeth, thus making it possible to increase the speed of engagement and achieve a substantial reduction in machining costs.

Claims

1. Coupling for rotationally connecting actuating shafts (1001;2001) of weave machines (1000) and weaving looms (2000), comprising at least one first clutch element (21) integral with the said shaft (1001) of the weave machine (1000) and a second clutch element (10) integral with the shaft (2001) of the weaving loom (2000), said second clutch element (10) comprising a disk (11) movable coaxially, owing to the thrusting action of associated means (13), for engagement with said first clutch element (21) integral with the shaft (1001) of the weave machine, there also being provided fixed means (15;15a) for recalling said disk (11) in the axial direction in order to cause disengagement thereof from the first clutch element (21) integral with the shaft of the weave machine (1000), characterized in that said disk (11) has first means (11b) and second means (lid) for engagement with corresponding means (21b) of the first clutch element (21) and with means (15d) of said second clutch element (15), respectively.

2. Coupling according to Claim 1, characterized in that said first clutch element integral with the shaft of the weave machine consists of a toothed wheel (21).

3. Coupling according to Claim 2, characterized in that said first engaging means of the first clutch element (21) consist of a set of front teeth (21b) on the said toothed wheel (21).

4. Coupling according to Claim 3, characterized in that said first engaging means of the disk (11) consist of a set of front teeth (11b) able to mesh with the corresponding set of front teeth (21b) of the toothed wheel (21).

5. Coupling according to Claim 1, characterized in that said second engaging means of the disk (11) consist of a set of front teeth (11d).

6. Coupling according to Claim 5, characterized in that said corresponding engaging means of the fixed assembly for recalling the disk (11) consist of a set of fixed front teeth (15d).

7. Coupling according to Claim 1, characterized in that said second engaging means of the disk (11) consist of a plurality of pins extending outwards parallel to the axial direction.

8. Coupling according to Claim 7, characterized in that said engaging means of the fixed assembly for recalling the disk (11) consist of a plurality of holes.

9. Coupling according to Claim 1, characterized in that said disk (11) is integral with a resilient ring (12) coaxially constrained to the shaft (2001) of the weaving loom (2000);

10. Coupling according to Claim 9, characterized in that said ring (12) is resilient in the axial direction and rigid in the radial and circumferential direction,

11. Coupling according to Claim 1, characterized in that said means for thrusting the disk (11) are resilient means (13).

12. Coupling according to Claim 11, characterized in that said resilient means are springs (13) housed in corresponding seats (14a) of a spring carrier (14) integral with the shaft (2001) of the machine (2000).

13. Coupling according to Claim 1, characterized in that said means for recalling the disk (11) consist of a coaxial annular electromagnet (15) fixed to the weaving loom (2000).

14. Coupling according to Claim 1, characterized in that the extension, in the axial direction, of the first means (11b) and second means (11d) for engagement of the disk (11) with the associated means of the first and second clutch element is such as to keep the disk in engagement with both of them until the disk itself is completely disengaged from one or other of the two clutch elements.

Drawing