Apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine

Abstract: Apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine comprises a detaching roller (3), a distributor valve (11) actuated by an electrical control, hydraulic means (9) actuated by pressurised fluid through the distributor valve (11) and kinematically connected to the detaching roller (3) to drive its rotation in both senses, a sensor (32) which generates a signal correlated to the progress of the combing machine operating cycle, a sensor (20) which generates a signal correlated to the angular position of the detaching roller (3) and an electronic control and drive unit (31) connected to the sensors (20, 32). To advantage, the operation of the distributor valve (11) is controlled by the electronic control and command unit (31) in dependence on the signals generated by the sensors so as to effect reciprocating rotation of the detaching roller (3) through different angles in accordance with the desired law of movement.

Description: The present invention relates to apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine, of the type comprising at least one detaching roller with a fixed axis and hydraulic drive means actuated by pressurised fluid through at least one distributor valve and kinematically connected to the at least one detaching roller to rotate it in both senses about the said axis. It is known that, in the spinning of cotton, linen and long fibres in general, the combing operation is carried out by a combing machine having a circular comb which rotates continuously, a straight comb, a movable gripper unit which substantially reciprocates, and detaching rollers. In each combing cycle of the machine, the detaching rollers must first rotate backwards through a predetermined angle to enable a predetermined length of the fibres which have already been combed to be superposed on those still to be combed and must then rotate forwards through a greater angle to advance the fibres to be combed. It is equally well known that, in the combing operation, it is of fundamental importance not only that the detaching rollers should be rotated through a given angle in one sense and through a different angle in the opposite sense but also that the rotations should take place with suitable laws of motion. More particularly, in order to avoid the combs carrying away the long fibres during the combing operation, it is necessary for the forward rotation of the detaching rollers to occur with a high initial acceleration and with a subsequent phase at constant velocity while it is best that the reverse rotation of these rollers should be rapid. In combing machines in current use, the rotary drive for the detaching rollers is derived from the main transmission of the combing machine. However, the provision of derived rotary drive for the detaching rollers has the disadvantage of requiring the provision of very expensive and complicated mechanical transmissions. Moreover because of the high operating rate of the combing machine, the constituent parts of the transmissions are subject to high accelerations and thus to high dynamic stresses. A further problem of these transmissions lies in the difficulty of driving the detaching rollers so that their movements accord with the desired law of motion and of varying the drive appropriately in a simple manner so as to optimise the law governing the movements of the detaching rollers according to the type of fibre to be combed. US Patent 3277790 discloses combing machines in which the reciprocating rotary drive for the detaching rollers is provided by an hydraulic motor supplied with pressurised fluid through a mechanically-controlled distributor valve. In order to drive the slide of the distributor valve, however, these machines require a very complicated cam system which has the disadvantages of being difficult to design, difficult to calibrate and not very satisfactory from the point of view of long-term reliability and precision in use following the inevitable wear of the parts. Other combing machines have been proposed in which the reciprocating rotary drive for the detaching rollers is provided by one or more electric motors coupled to the detaching rollers by reduction systems. This solution is not very satisfactory, however, since the electric motors intended for this use must operate intermittently and thus under conditions far from their optimum operating conditions so that, to obtain the power needed to drive the detaching rollers without causing excessive heating of the electric motors, it is necessary to use over-dimensioned electric motors. The inertia of the rotors of these motors also impedes the movement of the detaching rollers in accordance with the desired law of motion. The present invention is based on the technical problem of devising apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine which has structural and functional characteristics such as to overcome the problems mentioned with reference to prior-art combing machines. This problem is solved by an apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine of the type specified, which is characterised in that the at least one distributor valve is electrically operated and in that it includes a first sensor which generates a signal correlated with the progress of the combing machine operating cycle, a second sensor which generates a signal correlated with the angular position of the at least one detaching roller and an electronic control and command unit connected to the first and second sensors for controlling the operation of the distributor valve in dependence on the signals generated by the first and second sensors. Further characteristics and advantages of the apparatus according to the present invention will become apparent from the description of several embodiments given below, purely by way of non-limitative example, with reference to the appended drawings, in which: Figure 1 is a schematic view of apparatus according to the present invention, Figures 2, 3 and 4 are views of a detail of the apparatus of Figure 1, Figure 5 shows a different embodiment of a detail of the apparatus of Figure 1, and Figures 6 and 7 show different embodiments of the apparatus according to the present invention. With reference to Figures 1 to 4, apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine is generally indicated 1. The combing machine includes a continuously-rotating circular comb, a straight comb and a movable gripper unit which substantially reciprocates, which, being of known type, are not shown in the drawings and are not described in detail below in order not to burden the present description. The combing machine includes two parallel detaching rollers 3 with axes A-A, located adjacent each other at a predetermined spacing D, each of which has an associated pressure roller 4 located parallel to and above it, in pressing contact therewith. The combing machine can thus be seen to include two pairs 2 of parallel rollers each of which is constituted by a detaching roller 3 and a respective pressure roller 4 the peripheral surfaces of which are in pressing contact so that they are coupled together for rotation. The detaching rollers 3 and the pressure rollers 4 are rotatably supported at their ends by a frame 5 of the combing machine (Figure 2). The detaching rollers 3 of each pair 2 are kinematically connected together by a toothed transmission so that they are coupled together for rotation in the same sense. In the embodiment shown, the transmission is achieved by the keying of a gear 6 to each end of the detaching rollers 3 and the connection of the gears 6 of one detaching roller 3 to the corresponding gears 6 of the other detaching roller 3 by respective identical idle gears 7 and 8 supported for rotation by the frame 5 of the combing machine. The apparatus 1 includes an hydraulic motor 9 of known type, the rotary drive shaft 10 of which is connected for rotation to the hub of the idle gear 7. The hydraulic motor 9 is driven through an hydraulic distributor 11 by pressurised fluid from an hydraulic circuit 12 including a fluid reservoir 13, a motor pump unit 14 mounted on a duct P which puts the reservoir 13 in fluid communication with an inlet I of the hydraulic distributor 11 and a duct T connecting an outlet O of the hydraulic distributor 11 to the reservoir 13. The hydraulic circuit 12 further includes elements such as filters, pressure switches, surge chambers, non-return valves etc. which, being of known type, are not shown in the drawings and are not described in detail below in order not to burden the present description but which however are included as far as necessary for the proper operation of the equipment. The hydraulic distributor 11 is of the proportional type with an electromagnetically controlled distributor slide 15 biased into a central closed position (Figure 3) by a centring spring. Besides the inlet I and the outlet O the hydraulic distributor 11 also have two connections A and B in fluid communication with the hydraulic motor 9. The movement of the distributor slide 15 enables the inlet I and the outlet O of the hydraulic distributor 11 to be put into fluid communication with the connections A and B respectively or vice versa. The operation of the hydraulic distributor 11 is controlled by an electronic control unit 31 including an electronic amplifier 16 and an electronic data-processing unit 19. The electronic amplifier 16 is connected through an electrical conductor L1 to electromagnets 17 which drive the movements of the distributor slide 15. In addition, the electronic amplifier 16 is connected through a conductor S1 to a position detector 18, for example of the LVDT (linear variable differential transformer) type, associated with the distributor slide 15 and which can supply the electronic amplifier 16 with a signal related to the position of the distributor slide 15. The electronic data-processing unit 19 is interfaced with the electronic amplifier 16 and is connected through an electrical conductor S2 to a sensor 20, for example an encoder, associated with the idle gear 8. The sensor 20 supplies the electronic data-processing unit 9 with a signal related to the angular position of the idle gear 8 and hence of the detaching rollers 3. The electronic data-processing unit 19 is connected by an electrical conductor S3 to a sensor 32 which is associated with the circular comb and supplies the electronic data-processing unit 19 with an electrical signal related to the angular position of the circular comb. Since the operating cycle of the combing machine is repeated on each complete rotation of the circular comb, this electrical signal is thus correlated with the progress of the machine operating cycle. In a preferred embodiment, the electronic data-processing unit 19 includes a microprocessor 21 (CPU) which is interfaced with a video-keyboard unit 22, with RAM and EPROM memories 23, with an analog/digital signal converter 24 and with a data input/output card 25 respectively. The analog/digital signal converter 24, through a conductor L2, supplies the electronic amplifier 16 with a signal to be amplified for controlling the movement of the distributor slide 15. The data input/output card 25 is connected through the conductors S2 and S3 to the sensor 20 associated with the idle gear 8 and with the sensor 32 associated with a circular comb respectively, while it supplies the electronic amplifier 16 with an enabling signal through a conductor S4. The hydraulic distributor 11 may be replaced by an electrically-controlled, hydraulically-driven servovalve 26 for example of known two-stage type with nozzles 27 and a flapper plate 28 (Figure 5). The first stage of the servovalve 26 comprises a torque motor 29 which is connected to the electronic amplifier 16 through the conductor L1 and drives the movement of the flapper plate 28 between the nozzles 27. The second stage comprises a distributor slide 30 which enables an inlet I and an outlet O to be connected to respective connections A and B connected to the hydraulic motor 9 and vice versa. The fluid of the hydraulic circuit 12 acts on opposite end faces of the distributor slide 30 with an equal pressure only when the flapper plate 28 is equidistant from the nozzles 27. Consequently, when the torque motor 29 moves the flapper plate 28 towards one of the nozzles 27, the pressure difference which is set up between the ends of the distributor slide 30 causes the slide itself to move. The servovalve 2 has an advantage over the hydraulic distributor 11 in that it moves the distributor slide 30 by means of the power supplied by the hydraulic circuit 12 on which the regulation is effected since the torque motor 29, through the conductor L1, takes only the power needed to position the flapper plate 28 between the nozzles 27. In operation of the apparatus 1, the fibres to be combed pass through the gripper unit, are combed by the circular comb and by the straight comb and pass between the detaching roller 3 and pressure roller 4 of each pair 2, from which the fibres are drawn. At each rotation of the circular comb, the detaching rollers 3, as already stated in the introduction to the present description, rotate in the sense opposing the advance of the fibres and then rotate in the opposite sense through a greater angle. The reciprocating rotation of the detaching rollers 3 through different angles is effected by the connection of the connections A and B of the hydraulic distributor 11 alternately in fluid communication with the ducts P and T of the hydraulic circuit 12 by suitable movement of the distributor slide 15 so as to rotate the hydraulic motor 9 since a predetermined rotation of the drive shaft 10 of the hydraulic motor 9 corresponds to a rotation of the detaching rollers 3 through an angle which depends on the transmission ratio between the idle gears 7 and 8 and the gears 6. The movement of the distributor slide 15 is controlled by the electronic data-processing unit 19 which supplies the electronic amplifier 16 with an electrical control signal which depends on the signals received from the sensor 20 associated with the idle gear 8 and the sensor 32 associated with the circular comb. The control signal, after being processed appropriately by the electronic amplifier 16 in dependence on the signal supplied by the position detector 18 to the electronic amplifier 16, is fed to the electromagnets 17 of the hydraulic distributor 11 or, in the case of the servovalve 26, to the torque motor 29, so as to drive the required movement of the distributor slide 15. It should be stressed that the apparatus according to the present invention enables the movements of the distributor slide to be governed accurately and appropriately by the electronic control and command unit 31, which enables the flow of pressurised fluid to the hydraulic motor 9 to be regulated precisely so as to rotate the detaching rollers 3 through different angles in opposite senses as required for the correct operation of the combing machine. To advantage, it is possible to vary the law of motion which governs the rotation of the detaching rollers by varying the parameters set in the memory of the electronic data-processing unit 19 so as to satisfy various requirements. With reference to Figures 6 and 7, respective devices according to the present invention for providing reciprocating rotary drive to the detaching rollers of a combing machine are generally indicated 601 and 701, these parts which are structurally and functionally equivalent to corresponding parts of the apparatus 1 being indicated by the same reference numerals and not being described below so as not to burden the present description to no purpose. In the apparatus 601, the hydraulic drive means are constituted by two double acting hydraulic actuators 602 each having a piston head 603 defining two variable-volume chambers 604 and 605 within the actuator cylinder and a rod 606 fixed to the piston head 603. The rod 606 of each piston 603 is kinematically connected to a detaching roller 3 by a known rack and pinion transmission and a unidirectional clutch device which enables the reciprocating rectilinear movement of the piston 603 to be converted into discontinuous rotary drive for the detaching roller 3. In the embodiment shown, this transmission comprises, for each of the two hydraulic actuators 602, a rack 607 fixed for translational movement with the piston 603 and a pinion 608 meshed with the teeth of the rack 607 and keyed to a detaching roller 3 through a unidirectional clutch device 609, also known as a free wheel, which can transmit drive torque to the detaching roller 3 in only one rotational sense. In order to enable the detaching rollers to effect reciprocating movements through different angles, one of the two unidirectional clutch devices 609 transmits torque and rotational drive to the detaching roller 3 in the opposite sense from those transmitted by the other unidirectional clutch device 609, as will become clearer in the description below. For each hydraulic actuator 602, the apparatus 601 includes an hydraulic distributor 610 similar to the distributor 11 described above, having its inlet I and its outlet O respectively in fluid communication with the ducts P and T of the hydraulic circuit 12 and the connections A and B respectively in fluid communication with the variable-volume chambers 604 and 605 of the hydraulic actuator 602. Preferably the racks 607 are arranged, relative to the pistons 603 to which they are connected so that they supply pressurised fluid to one of the two variable-volume chambers 604 while simultaneously connecting the other to exhaust, or vice versa, so as to move the piston 603 of each hydraulic actuator 602 to rotate the pinions 608 in the same sense. The apparatus 601 further includes a manually-operable hydraulic distributor 611 having an inlet I connected to the pressurised fluid duct P, an outlet O connected to the duct T of the hydraulic circuit 12 and two connections A and B connected respectively in fluid communication with the connections A and B of the two hydraulic distributors 610. The hydraulic distributor 611 enables the pistons 603 of the two hydraulic actuators 602 to be put in phase with each other. In exactly the same manner as that described for the hydraulic distributor 11, in use of the apparatus 601, the two hydraulic distributors 610 are controlled by the electronic amplifier 16 independently of each other in dependence on the electrical signal transmitted to the latter by the electronic data processing unit 19. When pressurised fluid is supplied from the duct P into the variable-volume chambers 604 of the two hydraulic actuators 602 and the variable-volume chambers 605 are connected simultaneously to exhaust, the two pinions 608 rotate in the same sense and, as indicated above, only one of the two unidirectional clutch devices is able to transmit rotational drive to the respective detaching roller 3. When, on the other hand, pressurised fluid from the duct P is supplied to the variable-volume chambers 605 of the two hydraulic actuators 602 and at the same time the variable-volume chambers 604 are connected to exhaust, the two pinions 608 rotate in the opposite sense and rotational drive is transmitted to the detaching roller by the other unidirectional clutch device 609. From the above it will be clear that the length of travel of the piston 603 of one of the two hydraulic actuators 602 determines the amplitude of the rotation of the detaching rollers 3 in one sense while the amplitude of the rotation of the detaching rollers 3 in the other sense is determined by the travel of the piston 603 of the other of the two hydraulic actuators 602. Thus by varying the parameters set in the memory of the electronic data processing unit 19, it is possible to vary the law of motion which governs the rotation of the detaching rollers 3. In the apparatus 701, the hydraulic drive means are constituted by a double-acting hydraulic actuator 702 which includes a piston 703 defining two variable-volume chambers 704 in the hydraulic actuator 702 and a rod 705 connected to the piston 703. The rod 705 is fixed for translational movement with a rack 706 meshed with a pinion 707 kinematically connected to the hub of the idle gear 7 through a braked clutch unit 708 of known type. The braked clutch unit 708 comprises a friction disc fixed to an input shaft 709 to which the pinion 707 is keyed, a braked clutch disc fixed to an output shaft 710 to which the idle gear 7 is keyed, actuators, for example of electro-pneumatic type, for moving the clutch disc into engagement with the friction disc and friction means for braking the clutch disc when it is disengaged from the friction disc. An electronic control system 711 is connected to the braked clutch unit 708 by a conductor L3 and is connected to the electronic control and command unit 31 and, more precisely, to the electronic data processing unit 19, by an electrical conductor L4. Depending on the signal received from the electronic data processing unit 19, the electronic control system 711 causes the braked clutch disc to engage with the friction disc so as to connect the output shaft 710 rigidly for rotation with the input shaft 709. The apparatus 701 includes an hydraulic distributor 712 which is the same as the distributor 11 described previously having an input I and an outlet O respectively in fluid communication with the ducts P and T of the hydraulic circuit 12 and the connections A and B respectively in fluid communication with the variable-volume chambers 704 of the hydraulic actuator 702. In a manner entirely similar to that described for the hydraulic distributor 11, in use of the apparatus 701, the hydraulic distributor 712 is controlled by the electronic amplifier 16 in dependence on the electrical signal transmitted to the latter by the electronic data processing unit 19. The reciprocating rotation of the detaching rollers is achieved by the alternate supply of pressurised fluid from the hydraulic circuit 12 into one of the two variable volume chambers 704 of the hydraulic actuator 702 and the simultaneous connection of the other variable-volume chamber 704 to exhaust. By controlling the engagement and disengagement of the braked clutch disc and the friction disc through the electronic control system 711, it is thus possible to rotate the detaching rollers 3 in the two senses through different angles. The law of motion which governs the rotation of the detaching rollers 3 can be varied by varying the parameters set in the memory of the electronic data processing unit 19. As may be appreciated from the above, the apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine of the present invention enables the requirements referred to in the introduction to the present description to be satisfied while overcoming the problems of prior-art combing machines at the same time. A further advantage of the apparatus according to the present invention lies in the fact that it enables the law of motion which governs the rotation of the detaching rollers to be varied in a simple manner so as to optimise the operation of the machine to suit the type of fibres being combed. Another advantage of the apparatus according to the present invention lies in the fact that it is structurally and functionally simple so as to improve the reliability of the combing machine compared with that of prior-art machines. Obviously an expert in the art may make numerous modifications and variations to the apparatus for supplying reciprocating rotary drive to the detaching rollers of a combing machine as described above in order to satisfy various specific requirements, all of which however fall within the scope of protection of the invention as defined by the following claims. Thus, for example, the combing machine may include a larger number of detaching rollers and the sensor associated with the circular comb may be replaced by a sensor associated with part of the combing machine which moves cyclically during each working cycle of the machine.

Claims: Apparatus for providing reciprocating rotary drive to the detaching rollers of a combing machine, of the type comprising at least one detaching roller (3) having a fixed axis (A-A) and hydraulic drive means (9; 602; 702) actuated by pressurised fluid through at least one distributor valve (11; 26; 610; 712) and kinematically connected to the at least one detaching roller (3) to rotate it in both senses about the axis (A-A), characterised: in that the at least one distributor valve (11; 26; 610; 712) is electrically operated, and in that it includes a first sensor (32) which generates a signal correlated with the progress of the combing machine operating cycle, a second sensor (20) which generates a signal correlated with the angular position of the at least one detaching roller (3) and an electronic control and command unit (31) connected to the first sensor (32) and to the second sensor (20) for controlling the operation of the distributor valve (11; 26; 610; 712) in dependence on the signals generated by the first sensor (32) and the second sensor (20). Apparatus according to Claim 1, characterised in that it includes a plurality of detaching rollers (3) kinematically connected together. Apparatus according to Claim 1, characterised in that the hydraulic drive means comprise an hydraulic motor (9). Apparatus according to Claim 1, characterised in that the hydraulic drive means comprise, for each of the two senses of rotation of the detaching roller (3), a double-acting hydraulic actuator (602) having a rod (606) connected to the at least one detaching roller (3) by a rack (607) and pinion (608) transmission and a unidirectional clutch device (609). Apparatus according to Claim 4, characterised in that one of the unidirectional clutch devices (609) transfers rotational drive to the detaching roller (3) in the opposite sense from that transmitted by the other unidirectional clutch device (609). Apparatus according to Claim 4, characterised in that each hydraulic actuator (602) is supplied with pressurised fluid through a respective distributor valve (610). Apparatus according to Claim 1, characterised in that the drive means comprise a double-acting hydraulic actuator (702) having a rod (705) connected to the at least one detaching roller (3) by a rack (706) and pinion (707) transmission and a braked clutch unit (708). Apparatus according to Claim 7, characterised in that the engagement and disengagement of the braked clutch unit (708) is activated by an electronic control system (711) in dependence on the signals generated by the first sensor (32) and the second sensor (20). Apparatus according to Claim 8, characterised in that the electronic control system (711) is interfaced with the electronic control and command unit (31). Apparatus according to Claim 1, characterised in that the electronic control and command unit (31) comprises an electronic amplifier (16) and a data processing unit (19) interfaced with each other. Apparatus according to Claim 1, characterised in that the distributor valve (11; 26; 610; 712) has an associated position detector (18) which supplies the electronic control and command unit (31) with a signal correlated with the operating position of the distributor valve (11; 26; 610; 712). Apparatus according to Claim 1, characterised in that the at least one distributor valve (11; 26; 610; 712) is of proportional type. Apparatus according to Claim 1, characterised in that the at least one distributor valve (11; 26; 610; 712) is an hydraulic distributor (11; 610; 712) with a distributor slide (15). Apparatus according to Claim 13, characterised in that the hydraulic distributor (11; 610; 712) is electromagnetically controlled. Apparatus according to Claim 1, characterised in that the at least one distributor valve is a servovalve (26). Apparatus according to Claim 15, characterised in that the servovalve (26) is electrically controlled and hydraulically operated.

Inventors: VERZEGNASSI ANGELO, VERZEGNASSI, ANGELO, Verzegnassi, Angelo, c/o Vouk Macchine Tessili SpA
Applicants: VOUK S P A OFFICINE MECCANOTES, VOUK S.P.A. OFFICINE MECCANOTESSILI
Application year: 1995
Main classification: D01G19
IPC codes: D01G19