DRIVE SYSTEM FOR A PANTOGRAPH, AND METHOD FOR RAISING OR LOWERING

Abstract

A drive system for raising or lowering a sliding piece of a current collector for rail vehicles. The sliding piece is disposed on a positioning device of the current collector, and the sliding piece is configured to be brought into contact with an overhead line using contact pressure. The drive system includes a bellows drive which is actuated by compressed air to actuate the positioning device, and a pneumatic control unit having a control valve for supplying or withdrawing compressed air to/from the bellows drive. The drive system includes a detection line and a lowering valve for venting the bellows drive when pressure drops in the detection line, the lowering valve being a 3/2-way valve disposed in a pneumatic supply line between the control valve and the bellows drive.

Claims

1. A drive system for raising or lowering at least one sliding piece of a current collector for rail vehicles, the sliding piece being disposed on a positioning device of the current collector, said positioning device being adjustable by the drive system, and the sliding piece being configured to be brought into contact with an overhead line using a contact pressure, the drive system comprising a bellows drive which is configured to be actuated by means of compressed air for actuating the positioning device, the drive system comprising a pneumatic control unit having a control valve for supplying or withdrawing compressed air to/from the bellows drive, and the drive system comprising a lowering unit having a pneumatic detection line and a lowering valve for venting the bellows drive when pressure drops in the detection line, characterized in that the lowering valve is a 3/2-way valve, the lowering valve being disposed in a pneumatic supply line between the control valve and the bellows drive.

2. The drive system according to claim 1, wherein the lowering valve is a 3/2-way valve with spring return.

3. The drive system according to claim 1, wherein the lowering valve is configured to be pneumatically actuated via the detection line in such a manner that when there is an operating pressure in the detection line, the lowering valve opens the supply line and when pressure drops in the detection line, the lowering valve closes the supply line towards the control valve and vents the bellows drive.

4. The drive system according to claim 1, wherein the detection line is connected to a second pneumatic supply line of the control unit for forming the operating pressure in the detection line, a throttle valve of the lowering unit being disposed in the second supply line.

5. The drive system according to claim 4, wherein the second supply line is connected between the control valve and a compressed air source or between the control valve and a pressure regulator for forming an operating pressure.

6. The drive system according to claim 1, wherein the lowering unit is connected to the control unit via a pneumatic signaling line, the signaling line being connected to a pressure switch of the control unit and the detection line.

7. The drive system according to claim 1, wherein the control unit has an additional pressure switch which is connected to the supply line between the control valve and the bellows drive.

8. The drive system according to claim 1, wherein the control unit is connectable to a compressed air source and has a pressure regulator for forming an operating pressure.

9. The drive system according to claim 1, wherein the control valve is a 5/2-way valve, the control valve being configured to be actuated electromagnetically.

10. The drive system according to claim 1, wherein the control unit has at least one throttle check valve in the supply line the throttle check valve being connected between the control valve and the bellows drive, compressed air which is supplied to the bellows drive via the supply line by means of the throttle check valve being able to be throttled and compressed air which is withdrawn from the bellows drive being able to be conducted or vice versa.

11. The drive system according to claim 10, wherein the control unit has an additional throttle valve, compressed air which is supplied to the bellows drive via the supply line by means of the additional throttle valve or compressed air which is withdrawn from the bellows drive being able to be throttled.

12. The drive system according to claim 1, wherein the control unit, the lowering unit and the bellows drive are disposed so as to be spatially separated from one another.

13. A current collector having a positioning device, at least one sliding piece disposed on the positioning device and a pneumatic drive system according to claim 1.

14. A method for raising or lowering at least one sliding piece of a current collector for rail vehicles with a drive system, the sliding piece being disposed on a positioning device of the current collector, said positioning device being adjustable by the drive system, and the sliding piece being brought into contact with an overhead line using a contact pressure, a bellows drive of the drive system actuating the positioning device by means of compressed air, compressed air being supplied to or withdrawn from the bellows drive by means of a control valve of a pneumatic control unit of the drive system, and a pneumatic detection line and a lowering valve of a lowering unit of the drive system venting the bellows drive when pressure drops in the detection line, wherein a 3/2-way valve with spring return is used as a lowering valve, the lowering valve being disposed in a pneumatic supply line between the control valve and the bellows drive.

15. The method according to claim 14, wherein when pressure drops in the detection line relative to an operating pressure formed by a pressure regulator of the control unit, the lowering valve is switched in such a manner that the bellows drive is vented directly via the lowering valve and the sliding piece is lowered.

16. The method according to claim 14, wherein when the detection line is sealed tightly, said detection line is filled with compressed air until an operating pressure formed by a pressure regulator of the control unit is reached, the lowering valve being switched in such a manner when the operating pressure is reached in the detector line that the bellows drive is directly driven by compressed air via the supply line and the sliding piece is raised.

Description

[0026] Hereinafter, the disclosure will be described in more detail with reference to the accompanying drawing.

[0027] FIG. 1 shows a circuit diagram of a drive system according to the state of the art;

[0028] FIG. 2 shows a circuit diagram of a drive system.

[0029] FIG. 1 shows a circuit diagram of a drive system according to the state of the art for raising or lowering a sliding piece 11 of a current collector (not shown here) for rail vehicles according to the state of the art. Sliding piece 11 is disposed on a positioning device (also not shown here) of the current collector, said positioning device being adjustable by the drive system. The positioning device can be a so-called pantograph or another lever arm system, for example. Furthermore, drive system 10 comprises a bellows drive 12 for actuating the positioning device. By filling bellows drive 12 with compressed air, sliding piece 11 is brought into contact with an overhead line (not shown here) via the positioning device, sliding piece 11 being lowered again when bellows drive 12 is vented.

[0030] Furthermore, drive system 10 comprises a control unit 13 and a lowering unit 14. Lowering unit 14 is formed by a pneumatic detection line 15 and a lowering valve 16, which is formed by a differential pressure valve 17 or a 2/2-way valve in this case. Control unit 13 is connected to a compressed air source 18 and connected to bellows drive 12 via a supply line 19. Control unit 13 comprises a compressed air purifier 20, a pressure regulator 21 for forming an operating pressure, a manometer 22 for displaying an operating pressure, an overpressure valve 23 for limiting an operating pressure, a throttle check valve 24, another throttle valve 25 and a control valve 26. Control valve 26 is a 5/2-way valve 27 with electromagnetic drive and spring return.

[0031] In the switching position of control valve 26 illustrated in FIG. 1, bellows drive 12 is being vented. The venting is effected via additional throttle valve 25, causing a slow lowering of sliding piece 11. When sliding piece 11 is raised, control valve 26 is in its second switching position, in which the introduction of compressed air to bellows drive 12 via throttle check valve 24 is also decelerated.

[0032] When filling bellows drive 12 via supply line 19, detection line 15 is also pressurized and differential pressure valve 17 switches from the shown switching position for quick venting to the second switching position of differential pressure valve 17, supply line 19 being tightly sealed at differential pressure valve 17 against an environment in said second switching position. When pressure drops in detection line 15, a quick venting of the supply line or bellows drive 12 is effected by differential pressure valve 17 because of the pressure difference between supply line 19 and detection line 15.

[0033] Furthermore, the lowering unit is connected to control unit 13 via a signaling line 28, which is directly connected to detection line 15. Signaling line 28 acts on a pressure switch 29 of control unit 13, by means of which a parallel lowering of other current collectors which are disposed on the rail vehicle can be initiated.

[0034] FIG. 2 shows a drive system 30 for raising or lowering a sliding piece 31 of a current collector (not shown here) of a rail vehicles via a positioning device (also not shown here). Drive system 30 comprises a bellows drive 32 for actuating the positioning device and a control unit 33 and a lowering unit 34 for venting bellows drive 32 and for quickly lowering sliding piece 31. Lowering unit 34 comprises a detection line 35 and a lowering valve 36 for venting bellows drive 32, which is a 3/2-way valve 37 and which is disposed in a supply line 38 of bellows drive 32 in this case.

[0035] Control unit 33 is connected to a compressed air source 39 and has supply line 38. Control unit 33 also comprises a compressed air purifier 40, a pressure regulator 41, a manometer 42, an overpressure valve 43, a throttle check valve 44 and another throttle valve 45. Furthermore, control unit 33 comprises a control valve 46, which, in this case, is a 5/2-way valve which can be actuated electromagnetically and has a spring return. A function of control unit 33 largely corresponds to a function of the control unit described in FIG. 1. Here, in contrast, detection line 35 is connected to a second supply line 48 of control unit 33, via which an operating pressure is formed in detection line 35. Second supply line 48 is thus connected to supply line 38 downstream of pressure regulator 41 and upstream of control valve 46. Additionally, a signaling line 49 having a pressure switch 50 of control unit 33 is connected to detection line 35.

[0036] In addition to lowering valve 36, lowering unit 34 has a throttle valve 51 in second supply line 48. Filling or increasing the pressure in signaling line 49 and detection line 35 is effected in a decelerated manner via second supply line 48 and throttle valve 51. In this case, throttle valve 51 can alternatively be a gate or bottleneck in second supply line 48. When pressure drops in detection line 35, this pressure drop cannot be offset immediately via second supply line 48. Detection line 35 is connected to 3/2-way valve 37 and allows an actuation of 3/2-way valve 37.

[0037] In the illustrated switching position, bellows drive 32 is vented via 3/2-way valve 37. This switching position is reached by a spring return of 3/2-way valve 37, when a pressure has dropped in detection line 35. When an operating pressure is reached in detection line 35, 3/2-way valve 37 is switched to the second switching position, in which supply line 38 is switched so as to be interconnected or uninterrupted. Then, it is possible to raise or lower sliding piece 31 unhindered by means of bellows drive 32.