GB2160488A - A sliding door assembly for a rail vehicle - Google Patents

Abstract

The assembly comprises a door leaf 1 which is automatically closed by power drive means, in particular spring drive means 4, the door being openable manually against said drive means. The assembly includes for the purposes of force transmission between the drive means and the door leaf 1, a spiral cam 3 which is loaded by a pressure roller 6. The movement of the door is controlled by a damping cylinder unit 17 which is pneumatically controlled. <IMAGE>

Description

SPECIFICATION A sliding door assembly for a vehicle This invention relates to a sliding door assembly for a vehicle, particularly a rail vehicle, which door is automatically closed by power drive means, in particular by spring drive means, and is operable manually against said drive means.

Doors of this kind are used increasingly in rail vehicles in particular to avoid train delays due to the doors being left open by careless passengers.

The simplest closure drive means are springs or slide members, a disadvantage thereof being that, as a result of a long spring travel, an increasing amount of effort is required for completely opening the door. This can only be eliminated by means of expensive servo force-actuated drive means.

The present invention is therefore based on the problem, without the above-mentioned expensive constructions, of achieving as unifrom a force as possible over the opening or closing travel of the door, using simple means. According to the present invention there is provided a sliding door assembly for a vehicle such as a rail vehicle, including a door leaf which is automatically closed by power drive means and openable manually against said drive means, which assembly includes for the purposes of force transmission of the drive means to the door, a spiral cam which is loaded by a pressure roller. This arrangement make it possible to make do with a short spring travel and thus also to achieve only slight variations in the spring force and the resistance to movement of the door.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example to the accompanying drawings, in which: Figure 1 is an overal diagrammatic view of a sliding door assembly of the present invention, and Figure 2 is a longitudinal sectional view of a damping cylinder unit forming part of the assembly of Figure 1, to an enlarge scale.

As shown in the drawings a sliding door assembly of the invention, for a vehicle, is particularly suitable for a rail vehicle and includes a door leaf 1 of a sliding door fixed on carriers 13 to a guide means or ball race rail 14. The door leaf is openable in the direction indicated by the arrow 10 and closed in the direction indicated by the arrow 9 in Figure 1. To produce such movements, the door leaf 1 is coupled to a circulating endless flexible traction element 12 in the form of a belt or cable which passes over guide rollers 2 and 11. Arranged on a spindle 5 of the guide roler 2 and fixedly coupled thereto is a sprial cam disc 3 which at its periphery has a spiral cam means 7. A pressure roller 6 bears against the spiral cam means 7, being urged against the cam means 7 of the spiral cam disc 3 by a spring 4.By virtue of that arrangement, a torque is applied to the spiral cam disc 3 and thus to the guide roller 2. By way of the flexible element 12, the applied torque produces a drive means for the door leaf in the direction of closing as indicated by the arrow 9. The door is therefore held in the closed condition by the force of the spring 4 and must be opened manually by the traveller in the direction indicated by the arrow 10.

When that occurs, the spiral cam 3 is rotated and the spring 4 is stressed. As the radial travel of the pressure roller 6 is relatively slight when such movement occur, the force required in that respect dos not alter substantially from the beginning to the end of the closing movement.

The movement of the door on closing or opening thereof is controlled by a damping cylinder unit 17 whose piston rod 16 is connected to the door leaf 1 by means of a connecting member 15. As shown in Figure 2, the cylinder 17 has a stepped piston 20 whose front portion 19 engages into a reduced end portion 21 of the cylinder 17 with seal 22, and runs gently into that position in the final phase of the closing movement. The braking effect is produced by a regulating unit 23 which regulates the flow of air into and out of the cylinder 17, by virtue of the unit 23 including a throttle 29 which is adjustable by means of a screw and a check valve 30 which is connected in parallel with respect to the throttle 29 and which permits the air to pass through unimpededly when entering but blocks it off en issuing.By virtue of this arrangement, in the closing movement, as indicated by the arrow 27, the air is conducted by way of the throttle valve 30 and brakes the movement of the door while in the opening movement as indicated by the arrow 28, the intake of air occurs unimpededly, by way of the check valve 29. The position of the check valve 32 at the other end of the cylinder 17 is reversed. In this case also, the reduced piston portion 18 engages into a cylinder 24 with seal 25. However, in this case, the regulating unit 26 with the regulatable throttle valve 31 and the check valve 32 is connected in such a way that, upon opening movement, the air is discharged unimpededly, whereas in the closing movement, the air flow is throttled. The mode of operation is therefore as follows: In the opening movement of the door, the piston which is fixed on the cylinder rod passes into a cylinder.The air which is displaced thereby is pushed by way of a vent means disposed in the end portion of the cylinder, or is allowed to pass by way of the piston 20.

When now the self-closing effect due to the spring mechanism comes into operation, the piston again tries to slide out of its cylinder. However, that is controlled by a throttle means at the end portion of the cylinder. Depending on the way in which said throttle means is set, the piston passes out of its cylinder portion at a slower or faster speed. That produces the time delay before the closing operation.

Just before the final closed position a piston again passes into a cylinder portion and seeks to displace therefrom the air which is in the short cylinder portion. That is controlled by a throttle screw, thereby producing a delay effect prior to the closing movement being completed.

Both damping or delay element are disposed in an overal cylinder. That has the advantage that, in the event of subsequent automation of the door system, that cylinder can also be used as a drive cylinder. The invention is not restricted to the embodiment illustrated as the traction element used may also be a toothed belt or a simple belt which is wound on the roller 2, if there is no need for a delay in the closing movement. It is also possible for the guide roller 2 to be in the form of a gear wheel which co- operates with a toothed belt or a toothed rack connected to the door leaf 1. Instead of a coil spring 4, it is also possible to use a pneumatic spring in the form of a compressed air cylinder. If the periphery of the spiral cam means 7 is too short, it can be increased in length by the spiral cam disc 3 having a groove 8 into which the drive rolled can pass. It is also possible to provide pneumatic or hydraulic damping by a labyrinth means, similarly to shock absorbers, as a means for delaying the closing movement. That closing system affords an additional advantage when using double sliding doors. In this case, the directionchanging or guide system for one sliding door can be elongated, whereby in that case both doors can be closed with one closing system. That avoids the need for the conventional construction with two closing doors (one for each door leaf, as well as the additional direction-changing means). In the event of the system being automated, it is only necessary for the conduits required to be mounted to the cylinders which are already present, and possibly to provide the reversing means with spiral cable (control means is incorporated).

Claims (10)

1. A sliding door assembly for a vehicle such as a rail vehicle, including a door leaf, which is automatically closed by power drive means and openable manually against said drive means, which assembly includes for the purposes of force transmission, of the drive means to the door, a spiral cam which is loaded by a pressure roller.

2. An assembly according to claim 1, wherein the power drive means includes spring drive means.

3. An assembly according to claim lor claim 2, wherein the spiral cam, for transmitting its rotary movement, is coupled to the door leaf by way of a flexible element.

4. An assembly according to claim 3, wherein the flexible element is a circulating endless belt or cable drive.

5. An assembly according to any one of the preceding claims, wherein the spiral cam has a groove for increasing the angle of rotary movement.

6. An assembly according to claim 1, wherein the transmission of force from the spiral cam is effected by a toothed wheel or a toothed rack.

7. An assembly according to any one of the preceding claims, including a pneumatic cylinder with air throttle means for regulating the opening and closing movement respectively.

8. An assembly according to claim 7, wherein the cylinder has a stepped piston whose limit position regions have a different speed characteristic by adjustable regulating units connected thereto, for air control.

9. A sliding door assembly for a vehicle, substantially as hereinbefore described with reference to the accompanying drawings.

10. A vehicle having a sliding door assembly according to claim 1.