Device for driving the spindles in a ring spinning machine or the like

Abstract: In a ring spinning machine the spindles are rotated sectionally by providing several pairs of endless drive belts (7a, 7b), the belts of each pair rotating an equal number of spindles on the two faces of the spinning machine (1). Each pair of belts (7a, 7b) is driven by its own drive member arranged symmetrically to the paths of the belts of the respective pair. The drive member consists of a drive pulley (8) driven either directly by a motor (9) or via a transmission connected to a central motor. Deviation pulleys (12) are associated with each drive pulley to cause the belts (7a, 7b) to pass about opposite sides of the pulley (8) through large winding angles involving the entire periphery of the pulley (8) or more, and thus improve the traction effect of the pulley (8).

Description: This invention relates to a device for driving the spindles in a ring spinning machine or the like. In ring spinning machines it is known to rotate the individual spindles, arranged on the two faces of the spinning machine, by a single drive belt which extends endlessly in tangential contact with the rotation pulleys of all the spindles, the belt being driven by a motor. To ensure sufficient tangential contact, suitable tensioning rollers are provided between pairs of adjacent spindles. This arrangement however suffers from starting difficulties when the number of spindles to be driven is very large. It has already been proposed to drive the belt by several drive units distributed along the machine on the inside of the belt perimeter. The belt is deviated towards the drive unit at each of these latter by two deviation pulleys. To prevent belt portions moving in two different planes the two deviation pulleys are positioned in the same plane and spaced apart in the longitudinal direction of the spinning machine, but this means that those spindles in positions corresponding with the deviated portion cannot be driven by the belt. It therefore becomes essential to provide a second belt at each drive unit to drive the spindle or spindles not engaged by the main belt, this second belt being driven by the relative pair of deviation pulleys. This however complicates the spinning machine structure at each drive unit. In addition, it must be ensured that on starting, all the drive units accelerate at the same rate to prevent the main belt slipping or undergoing tension irregularities, with consequent increased wear and reduced life of this belt. This known arrangement also has the drawback that the winding angle of the main belt about the drive pulleys of the drive units is limited and cannot exceed a certain value because of the arrangement of the deviation pulleys. The result is that for equal spindle numbers and characteristics, a greater number of drive units is generally required to prevent slippage. DE-B-1 141 571 discloses a spinning machine with a number of spindles driven by a pair of belts driven by a common drive pulley. Said belts have an arc of contact with the respective common drive pulley lower than 180°, so that they show a path V-shaped around the drive pulleys. EP-A-0 326 003 discloses a spinning machine with a plurality of drive pulleys that drive a single belt that shows a path U-shaped by deviating pulleys in front of the macghine. US-A-1 442 037 discloses an endless drive arrangement for rotating two sets of spindles utilizing several double-grooved drive pulleys. In fact, this reference depicts a spinning machine that has two fronts of spindles driven by two flights of a common belt. Such two flights are driven by several drive pulleys with double grooves 6/7 in different horizontal planes. The object of the present invention is to overcome these drawbacks and limitations by providing a drive device of the stated type by which the drive conditions of the various spindles are improved in the sense of preventing slippage as far as possible, within the context of low constructional effort and cost. This object is attained by a device for driving the spindles in a ring spinning machine or the like in which the spindles are rotated by tangential contact between respective spindle pulleys and an endless drive belt according to claim 1. Advantageously the two belts of each pair pass about the same drive pulley on circumferentially opposite sides thereof and in different planes, so that the entire periphery of the drive pulley is used for traction, which would not be possible with a single belt wound as in the known art. The result is that with the present device the drive conditions are better, enabling either the number of drive units to be reduced or the number of driven spindles to be increased for the same number of drive units, and in addition the slippage margins are greater so decreasing drive belt wear. The drive members can consist of relative drive pulleys, each associated with its own motor or receiving motion from a transmission connected to a single motor. A device according to the invention does not require the provision of auxiliary belts for driving spindles excluded from the main drive, and in addition does not involve constructional complications in that the single belt arrangement requires only the provision of relative deviation members, which can be common for adjacent belts. As the individual drive units are associated with independent pairs of belts, any acceleration differences during the starting of one unit compared with another have no effect on the belts. Further details and advantages of the invention will be more apparent from the description of some preferred embodiments thereof described hereinafter and illustrated by way of example on the accompanying drawings, in which: Figure 1 is a schematic plan view of a first embodiment of a drive device according to the invention; Figure 2 is a schematic side elevation of the same device; Figure 3 is an enlarged view of the device of Figure 1 at the drive units; Figure 4 is a schematic side elevation of a second embodiment of a device according to the invention. The figures show very schematically a ring spinning machine 1 provided with a plurality of spindles 2 arranged on two faces of the spinning machine (only some of the spindles are shown, for simplicity), each spindle being provided lowerly in known manner with a drive pulley 3 to be tangentially engaged by a drive belt. The tailstock of the spinning machine 1 carrying the control members for the drafting units 4a is indicated by 4, whereas the spinning machine headstock, which mainly carries the suction members, is indicated by 5. Tensioning rollers 6 are arranged between pairs of pulleys 3, all in known manner. For driving the spindles 2 the invention provides for sectional drive, the number of sections being two in this particular case. The spindles 2 of the sections are driven by respective pairs of drive belts 7a, 7b such that the belts of each pair rotate the same number of spindles 2 on the two faces of the spinning machine 1. It is not necessary for each pair of belts 7a, 7b to drive the same total number of spindles 2. This can also be deduced from Figure 1, in which the belt pair 7a, 7b on the left drives a smaller number of spindles 2 than the pair on the right. For constructional economy reasons it may however be appropriate to divide the drives such that each belt pair 7a, 7b drives the same number of spindles 2. Each belt pair 7a, 7b is driven by its own drive member 8 consisting of a main drive pulley positioned substantially symmetrical to the trajectory of the associated belt pair 7a, 7b. The pulley 8 can be operated directly by its own electric motor 9. Each belt pair 7a, 7b travels about deviation pulleys 10, 11 of vertical axis, these pulleys being common for adjacent belts 7a, 7b and operating the drafting units 4a by known means (Figure 2). As can be seen in Figures 2 and 4, this arrangement means that the adjacent belts 7a, 7b move in alternately different horizontal planes, but each belt remains entirely in its own plane, so that regular operation of the respective spindles 2 is ensured. Within the drive units there are provided a further two deviation pulleys 12 in diametrically opposite positions about the relative drive pulley 8, and in different planes. The pulleys 12 are positioned such as to cause the belts 7a, 7b to undergo substantially S-shaped paths by passing about opposite sides of the pulley 8 through relatively wide winding arcs which in total occupy the entire periphery of the pulley 8. The arrangement as described and illustrated enables the entire periphery of the pulleys 8 to be used (although in different planes) as traction surfaces. By thus splitting the belts and arranging them symmetrically about the drive members 8 it is therefore possible to obtain a total winding angle which is at least equal to 360°, which would not be possible if only one belt were present, passing about the pulley 8 in known manner. It will be apparent that for equal numbers of driven spindles, the improved total winding angle obtainable by a device according to the invention provides a greater margin of protection against slippage, or alternatively allows the number of drive points along the spinning machine 1 to be reduced, and thus results in lesser drive synchronization problems. It will be noted that by suitably positioning the deviation pulley 12, for example on a diameter parallel to the longitudinal direction of the spinning machine 1, the winding angle of each belt 7a, 7b exceeds 180°, so that the total winding angle of the two belts 7a, 7b exceeds 360°. The greater expense of arranging a plurality of belts is therefore compensated by a greater regularity of spindle drive. Any operational irregularities can be remedied directly within that part of the spinning machine in which they occur, as they do not affect the rest of the spinning machine. Instead of providing individual motors 9 for each drive member 8, it is possible to provide a single central motor 13 for example in the headstock 5 of the spinning machine 1, to drive the various pulleys 8 via a transmission 14 with branches 15, as shown in Figure 4. With the present device the spindle drive can also be separated from the drafting unit drive, to the advantage of operational regularity of both drives, by adding to the mechanical part of the drafting units 4a a driver synchronized with the spindle 2, such as a motor 4b controlled by an inverter 4c in accordance with the frequency. The number of separate spindle drive units can be different from that illustrated by way of example, and the path taken by the belts 7a, 7b at the drive members 8 could also be varied, possibly by providing further deviation pulleys to further improve the winding angle of the belts about the pulleys 8.

Claims: A device for driving spindles in a ring spinning machine comprising spindles (2) which are rotated by tangential contact between respective spindle drive pulleys (3) and endless drive belts (7), each of said drive belts (7a and 7b) including opposite generally parallel belt runs and a bight run connected therebetween, said drive belts (7a,7b) being disposed in different planes, the drive belts of each pair rotating an equal number of said spindles on two faces of the spinning machine, each of said pair of drive belts (7a and 7b) being driven by an associated drive pulley (8) arranged substantially symmetrically to the paths of the drive belts (7) of the respective pair, at least a first pair of deviation pulleys (10) is provided at each of said drive pulleys along the faces of the spinning machine and is associated with a respective one of said drive pulleys (8) at diametrically opposing positions and in different planes so as to cause the bight run of each pair of belts to undergo a substantially S-shaped path by passing about opposite sides of the respective drive pulley (8) through winding angles which in total involve the entire periphery of said respective drive member, characterised by further comprising a second pair of deviation pulleys (12) being disposed adjacent said drive pulley and in generally opposite diametrical relationship thereto, said first pair of deviation pulleys being located one each at a juncture of said first and second belt runs and the bight runs thereof; said first belt bight run being at least partially entrained about said drive pulley (8) and both said first pair of deviation pulleys (10) and only one of said second pair of deviation pulleys (12); said second belt bight run being at least partially entrained about said drive pulley (8), and both said first pair of deviation pulleys (10) and only one of said second pair of deviation pulleys (12). A device as claimed in Claim 1, characterised in that said drive pulleys (8) are each operated by an own motor (9). A device as claimed in Claim 1, characterised in that said drive pulleys (8) are operated by a single central motor (13) via a transmission (14). A device as claimed in Claim 1, characterised in that the belts (7a and 7b) of adjacent pairs slide about common deviation pulleys (10 and 11). A device as claimed in Claim 1, characterised in that adjacent belts move in two different horizontal planes. A device as claimed in Claim 1, characterised in that deviation pulleys (12) are provided at said drive members to cause said belts (7) to undergo paths such that they pass about said drive pulleys (8) through angles exceeding 180° in different planes respectively.

Inventors: COSSANDI SANTINO, PEZZOLI LUIGI, COSSANDI, SANTINO, PEZZOLI, LUIGI
Applicants: MARZOLI & C SPA, FRATELLI MARZOLI & C. S.P.A.
Application year: 1991
Main classification: D01H1
IPC codes: D01H1