Control unit for the pneumatic actuation of an active creel

Abstract

A control unit for pneumatic actuation of a cylinder, in particular an active creel of a textile-processing machine or a cabling machine, having a compressed air inlet for connecting a compressed air supply, a working air outlet for operating the cylinder, which acts at least on one side, a valve unit arranged between the compressed air inlet and the working air outlet, and an operating element for opening the valve unit to trigger a lifting movement of the cylinder. In order to provide a control unit for pneumatic actuation of an active creel, the actuation of the creel being particularly simple by the control unit, so that an operator can use the creel more easily, quickly and safely, and in addition the creel is protected from damage by incorrect operation, the control unit for achieving a self-retaining valve function, in which the lifting movement of the cylinder is fully executed with a single and/or brief actuation of the operating element, and for the control unit is connected to an end position sensor of the cylinder such that, when the end position sensor is activated, the valve unit is closed and/or the cylinder connected to the working air outlet is automatically depressurized when or after an end position is reached.

Claims

1. A control unit for pneumatic actuation of an active creel of a textile-processing machine, the control unit comprising: a compressed air inlet for connecting a compressed air supply, a working air outlet for operating the cylinder acting at least on one side, a valve unit arranged between the compressed air inlet and the working air outlet, and an operating element for opening the valve unit to trigger a lifting movement of a cylinder, characterised in that the control unit for achieving a self-retaining valve function, in which the lifting movement of the cylinder is fully executed with a single and/or brief actuation of the operating element, and in that the control unit is connected to an end position sensor of the cylinder in such a way that, when the end position sensor is activated, the valve unit is closed and/or the cylinder connected to the working air outlet is automatically depressurized when or after an end position is reached, and in that the control unit has a sensor air inlet.

2. The control unit according to claim 1, characterised in that the control unit has the sensor air inlet for connecting the end position sensor, with the valve unit being closed in an event of a pressure increase, an exceeding of a threshold pressure value, a sensor pressure not being present at the sensor air inlet, the cylinder connected to the working air outlet is automatically depressurized when or after an end position is reached, or a combination thereof.

3. The control unit according to claim 2, characterised in that the sensor air inlet is arranged such that a pressure applied to the sensor air inlet counteracts the force of a magnet, the sensor air inlet being connected to a closed valve chamber arranged between the housing of the control unit and the magnet.

4. The control unit according to claim 1, characterised in that the valve unit has a slider displaced from a closed position into an open position of the valve unit by actuation of the operating element inside the control unit, the slider having a duct which, in the open position, connects the compressed air inlet to the working air outlet.

5. The control unit according to claim 4, characterised in that a magnet is arranged on the slider or opposite the slider on a housing of the control unit such that the slider is held in the open position of the valve unit by the force of the magnet in the open position.

6. The control unit according to claim 1, characterised by a second operating element which is only activated if the first operating element has been actuated and/or by which the position and/or the function of the first operating element is immediately reversed.

7. A creel for a textile-processing machine with a control unit for pneumatic actuation of a cylinder, the control unit with: a compressed air inlet for connecting a compressed air supply, a working air outlet for operating the cylinder acting at least on one side, a valve unit arranged between the compressed air inlet and the working air outlet, and an operating element for opening the valve unit to trigger a lifting movement of the cylinder, characterised in that the control unit for achieving a self-retaining valve function, in which the lifting movement of the cylinder is fully executed with a single and/or brief actuation of the operating element, and in that the control unit is connected to an end position sensor of the cylinder in such a way that, when the end position sensor is activated, the valve unit is closed and/or the cylinder connected to the working air outlet is automatically depressurized when or after an end position is reached, and the cylinder for carrying out a lifting movement, wherein the control unit and/or the cylinder are formed in such a way that the cylinder is automatically depressurized when or after an end position of the lifting movement is reached, and in that the control unit has a sensor air inlet.

8. The creel according to claim 7, characterised in that at one end in the region of a piston rod outlet opening, the cylinder has a sensor range with a sensor air outlet as the end position sensor, which is connected to the sensor air inlet of the control unit for closing the valve unit, the sensor range being formed in such a way that shortly before the end position of a displaceable piston is reached in the cylinder there is an increase in the sensor range.

9. The creel according claim 8, characterised in that at least one throttle opening penetrating the piston is provided in the piston in order to increase the pressure build-up in the sensor range when the end position is reached by the working air.

10. The creel according to claim 7, characterised in that the cylinder has a cross-sectionally reduced area in the sensor range, and a sensor piston with a diameter corresponding to the diameter of the cross-sectionally reduced area is arranged on the piston on the side facing the cross-sectionally reduced area, which enters the cross-sectionally reduced area in the cylinder shortly before the end position of the piston is reached, so that the pressure in the sensor range and thus at a sensor air outlet increases.

11. A method for active pneumatic movement of a cylinder, the method comprising: actuating an operating element of a control unit, in which case a valve unit of the control unit arranged between a compressed air inlet and a working air outlet is opened at least as long as a movement of the cylinder is fully executed out by a cylinder connected to the working air outlet and acting at least on one side, and monitoring of the movement of the cylinder by the control unit, the valve unit being closed at a sensor air inlet of the control unit when the pressure rises and/or a threshold pressure value is exceeded and/or the cylinder connected to the working air outlet is automatically depressurized when or after an end position is reached, wherein the movement of the cylinder is a lifting movement of the creel.

12. The method according to claim 11, characterised in that the operating element is automatically brought back into an initial position on or after the closing of the valve unit due to the increasing pressure at the sensor air inlet and is thus released for a next actuation.

13. The method according to claim 11, characterised in that, when the valve unit is closed and a slider of the valve unit is displaced, the sensor air inlet and/or the working air outlet of the valve unit are released for venting.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An embodiment example of a control unit, further parts of a creel as well as a method for the active pneumatic lifting of a creel are explained in more detail below with reference to the drawings. In the drawings:

(2) FIG. 1a illustrates a perspective view of a control unit,

(3) FIG. 1b illustrates a perspective sectional view of the control unit shown in FIG. 1a,

(4) FIG. 2 illustrates a perspective cross-sectional view of a cylinder, and

(5) FIG. 3 illustrates a diagram illustrating the basic principle of a method for active pneumatic lifting of a creel by a control unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) In a version shown in FIGS. 1a and 1b of a control unit 1 formed as an integral unit for the pneumatic control of an active creel of a textile-processing cabling machine, two operating elements 6, 13 are arranged on one side on the outside of a housing 11 and three connections are arranged on another side. The first connection is a compressed air inlet 2 to which a compressed air hose for supplying compressed air with 6 bar pressure to control unit 1 and subsequently to a pneumatic cylinder 4 of the creel can be arranged. A working air outlet 3 is arranged directly next to it as a second connection, which is intended to direct compressed air as working medium to at least one pneumatic cylinder 4. In addition to these two connections, the third connection on the housing 11 is a sensor air inlet 7 on the control unit 1, to which a compressed air line coming from a pneumatic sensor or a sensor range 15 of the pneumatic cylinder 4 can be connected.

(7) Inside the housing 11 of the control unit 1, a valve unit 5 is arranged which is essentially formed by a slider 8, which is also cylindrical and can be displaced within a cylindrical section of the housing 11. The slider 8 can be moved by the operating elements 6, 13 and can be moved between a closed and an open position of the valve unit 5. FIG. 1 shows control unit 1 with valve unit 5 in the open position.

(8) The slider 8 has a duct 9 on its surface which, in the open position of the valve unit 5, connects the compressed air inlet 2 with the working air outlet 3. If slider 8 is moved to the closed position of valve unit 5, the duct 9 is only in the area of compressed air inlet 2, but no longer in the area of working air outlet 3, so that compressed air can no longer flow from compressed air inlet 2 through valve unit 5 into working air outlet 3 and from there to a pneumatic cylinder 4.

(9) The first operating element 6 is directly connected to the slider 8 of the valve unit 5, so that pressing in the operating element 6 moves the slider 8 to the open position of the valve unit 5. Accordingly, the first operating element 6 triggers a lifting movement of the creel due to activation of the pneumatic cylinder 4. The operating element 6 is arranged so that it can be moved along a central longitudinal axis of the slider 8.

(10) By a fixed rocker 22, the first operating element 6 is connected to the second operating element 13 arranged above it in such a way that both operating elements 6, 13 are basically in different operating statuses. If the first operating element 6 is pressed, the second operating element 13 simultaneously returns from the pressed position to a position in which it can be actuated, while a renewed actuation of the first operating element 6, which has already been pressed in, is then no longer possible. The second operating element 13 is therefore used to reverse the function of the first operating element 6 and to immediately cancel a process triggered by the first operating element 6.

(11) In order to ensure a reliable, self-retaining valve function, a permanent magnet 10 is arranged at one end of the slider 8 opposite the first operating element 6, and in the open position of the valve unit 5, the permanent magnet 10 is brought close enough to an iron plate 26 arranged on the housing 11 of the control unit 1, so that magnetic attraction occurs and a special magnetic retaining function therefore occurs in the open position of the valve unit 5. Therefore it is necessary to overcome the holding force of the magnet 10 to close the valve unit 5. The iron plate 26 is preferably fixed directly to the housing 11 of control unit 1 or forms part of the housing 11.

(12) In order to move the slider 8 into the closed position of the valve unit 5 against the holding force of the magnet 10, a valve chamber 12 is arranged between the housing 11 in the area of the iron plate 26 and the surface of the slider 8 having the magnets 10, which is connected to the sensor air inlet 7. When the pressure at the sensor air inlet 7 rises and thus in the valve chamber 12, the pressure acting on the slider 8 exceeds the magnetic holding force after a certain time, minus the spring force of the spring 23, and the valve unit 5 switches abruptly from the open to the closed position.

(13) In order to support a complete and safe switch-over from the open position to the closed position, a spiral spring 23 is arranged on the first operating element 6, which pretensions the operating element 6 against the holding force of the magnet 10 towards the closed position. For this purpose the spiral spring 23 is arranged around the first operating element 6.

(14) The pneumatic cylinder 4 shown in FIG. 2 has a displaceable piston 17 with a piston rod 24 emerging from one side of the pneumatic cylinder 4 out of a piston rod outlet opening 14. The pneumatic cylinder 4 is designed to act on one side only, i.e. only on the side of the piston 17 opposite the piston rod 24 can the compressed air leaving the working air outlet 3 of control unit 1 be introduced into a working air inlet 27. This compressed air then moves the piston 17 within the pneumatic cylinder 4 in such a way that the piston rod 24 emerges from the piston rod outlet opening 14 and can thus effect a lifting movement of a creel.

(15) In order to be able to vent the opposite side inside the pneumatic cylinder 4 during this movement, two ventilation holes 25 are arranged in the area of the end having the piston rod outlet opening 14. If the piston 17 is pushed in again, for example due to the weight of a creel arranged at least indirectly on the piston rod 24, air enters the pneumatic cylinder 4 through the ventilation holes 25, so that the piston 17 moved downwards with damping. The piston 17 is vented by the cross-sectional resistance of the working air inlet 27 and/or the working air outlet 3 of control unit 1 as well as by a ventilation hole 28.

(16) Furthermore, the pneumatic cylinder 4 has a sensor range 15 at the end having the piston rod outlet opening 14, which sensor range is formed by a cross-sectionally reduced area 18. The ventilation holes 25 are arranged in front of the cross-sectionally reduced area 18, while at the end of the cross-sectionally reduced area 18, directly next to the piston rod outlet opening 14, a sensor air outlet 16 is arranged, which is directly connected to the sensor air inlet 7 of the control unit 1.

(17) A sensor piston 20 is arranged directly on the piston 17 on the side of the piston 17 facing away from the working air and/or the working air inlet 27, in which case the sensor piston 20 has a smaller diameter than the piston 17 and is arranged coaxially to the piston 17. The diameter of the sensor piston 20 corresponds to the diameter of the cross-sectionally reduced area 18. Towards the end of the stroke, the sensor piston 20 dips into the cross-sectionally reduced area 18 and builds up a pressure in the sensor range 15 as a result of the further lifting movement. This pressure is then transmitted through the sensor air outlet 16 to the sensor air inlet 7 of the control unit 1 and reaches the valve chamber 12 there.

(18) Now the pressure builds up continuously in the valve chamber 12 and as soon as the area-proportional pressure force exceeds the magnetic holding force of the permanent magnet 10, the slider 8 in the valve unit 5 moves abruptly to the right in FIG. 1, i.e. into the closed position, in which case the working air outlet 3 is shut off from the compressed air inlet. At the same time, the working air outlet 3 and the sensor air inlet 7 are released for venting. Thus the pneumatic cylinder 4 is pressureless on both sides.

(19) In addition, the movement of the slider 8 disengages the first operating element 6 and moves the second operating element 13 in the opposite direction to the first operating element 6 via the rocker 22. As a result, the creel is now in the upper position, the pneumatic cylinder 4 is completely pressureless and the control unit 1 is again in the initial position. The creel is secured against falling down by the usual measures, for example by a spring or a movement of the centre of gravity beyond the swivel axis.

(20) In order to increase the pressure build-up in the sensor range 15 of the pneumatic cylinder 4 and, if necessary, to be able to shorten the cross-sectionally reduced area 18, a throttle opening 21 can be arranged to penetrate the piston 17 and the sensor piston 20. When the end position is reached, the working pressure can then penetrate through this throttle opening 21 through the piston 17 and act on the sensor range 15.

(21) Finally, FIG. 3 schematically shows a basic principle for the implementation of a method for the operation of a creel, in which the pressureless switching is achieved by a position switching valve in the sensor range 15 outside the pneumatic cylinder 4. The position switching valve is switched by a mechanical contact when the end position is reached. FIG. 3 shows the basic principle in general, how it can be operated by different devices and also by the control unit 1 according to the present invention.

(22) In the initial status shown in section a) of FIG. 3, a creel is in the lower loading position and is subsequently to be lifted by the pneumatic cylinder 4. The first operating element 6 is ready for operation. The position sensing valve in sensor range 15 is inactive and control unit 1 has completely vented the pneumatic cylinder 4.

(23) If an operator now presses the first operating element 6, which corresponds to the state shown in section b) of FIG. 3, a valve unit 5 of control unit 1 is moved into an open position and compressed air flows into pneumatic cylinder 4, which thereby extends and lifts the creel to bring it into an operating position. At the same time as the first operating element 6 is pressed, the pressure circuit is also pressurized by the position switching valve in sensor range 15. Even if the operator releases the first operating element 6, it remains in the pressed position. Control unit 1 is switched back by the position sensing valve in the sensor range 15 interrupting or depressurizing the pressure circuit and releasing operating element 6, and the position sensing valve in sensor range 15 being switched ready for operation.

(24) When the end position of the creel is reached, the active position switching valve is triggered, and at the same time the first operating element 6 is pressed out again into the starting position, as shown in section c) of FIG. 3. At the same time as the valve unit 5 is closed, the pneumatic cylinder 4 is depressurized by venting the working pressure outlet 3 and the sensor air inlet 7 of control unit 1.

(25) Finally, the creel can be lowered manually by the operator as shown in section d) of FIG. 3, in which case this is damped by the pneumatic cylinder 4.

LIST OF REFERENCE SIGNS

(26) 1 Control unit 2 Compressed air inlet 3 Working air outlet 4 Cylinder 5 Valve unit 6 Operating element 7 Sensor air inlet 8 Slider 9 Channel of the slider 10 Magnet 11 Housing of the control unit 12 Valve chamber 13 Second operating element 14 Piston rod outlet opening 15 Sensor range 16 Sensor air outlet 17 Piston 18 Cross-sectionally reduced area 19 Side of the piston 20 Sensor piston 21 Throttle opening 22 Rocker 23 Spring 24 Piston rod 25 Ventilation hole 26 Iron plate 27 Working air inlet 28 Ventilation hole