Brake for a rail vehicle

This invention relates to a brake for a rail vehicle, particularly but not exclusively a hand brake which can be operated by a handwheel.

Conventionally hand brakes use a system of levers to apply a friction pad to the brakes of a rail vehicle, such as a goods wagon. One example of such a known mechanism is disclosed in US published patent application US2005034933.

Regulations, at least in the UK, dictate that hand brakes should be applied using a handwheel and that each wagon should have its own hand brake. Known levers connected to such handwheels wear during use, which results in an increase number of turns to apply the hand brake. Applying hand brakes to many wagons is time consuming and increasing the number of turns to apply the hand brake increases this time considerably

Additionally, mechanical linkages need constant maintenance and often become damaged or corroded in use, necessitating frequent repair. Such maintenance and repair is awkward when, as is usually the case, the linkages are inboard of the wheels.

Embodiments of the present invention address the problems mentioned above. According to a first aspect the present invention consists in a rail vehicle brake apparatus including at least one cable and an actuator, the or each cable having an inner section and an outer sheath moveable relative to the inner section, the or each cable being connected, at an actuator end, to said actuator, and connectable at a brake end, to a rail vehicle wheel brake mechanism, an

element of the actuator being rotatable about an axis to cause relative substantially linear movement between the inner section and the sheath of the or each cable, in the direction of the axis, for operating the brake mechanism.

In this way there can be movement of the brake mechanism without intervening lever movements between the actuator and the brake mechanism.

Consequently there are no non-linear losses in movement. The inner section of the cable and/or the outer sheath may be rigid in the direction of movement, and may be resilient laterally to the direction of movement.

In an embodiment said at least one cable comprises first and second separate cables each connectable at said brake ends to separate brake mechanisms and wherein, at the actuator ends, they approach the actuator from opposing directions.

Preferably the actuator comprises a screw and a complementary nut and said element is the screw or nut, relative rotation of which causing substantially linear movement in said axis, one of the screw or nut being operably connected to an inner section of the first cable and to a sheath of the second of the cables, at said actuator ends.

When the apparatus is arranged as mentioned immediately above, said linear movement results in a pulling of the inner section of the first cable relative to its sheath and in a pushing of the sheath of the second cable relative to its inner section. In each cable of the pair, at the actuator end of each cable, the distance between the end of the inner section and its respective sheath is caused to increase and this results in a pulling of the inner section relative to the sheath at the brake ends. This pulling can be used to apply the brakes.

In a particularly preferred embodiment, the screw is rotatable within a fixed support and the nut is slidably held in the support on the screw. More particularly, the nut is operably connected to the inner section of the first cable and to the sheath of the second cable. Furthermore the sheath of the first cable and the inner section of the second cable are held by the fixed support. The inner section of the first cable and to the sheath of the second cable may be held on either side of the screw by a yoke which may be pivotally mounted to the nut about a pivot axis which may be approximately normal the axis of rotation of the screw. In a particularly preferred embodiment the screw is in rotational communication with at least one hand wheel. Preferably said at least one hand wheel includes to wheels one of which includes means between the wheel and screw for reversing the sense of rotation. Thus when a pair of wheels are used, one on each side of a wagon, the rotation direction, for example clockwise, for applying the brakes is the same on each side of the wagon.

Preferably the brake apparatus includes an indicator to show the state of the brakes, for example, on or off.

Although the invention has been outlined above it is to be understood that it includes any novel features or any novel combination of features herein, whether or not such features are described herein in that combination.

The invention may be performed in various ways and a specific embodiment will now be described, by way of example, with reference to the accompanying drawings, wherein:

Figure 1 shows a simplified schematic representation of a hand brake for

a railway wagon; and

Figures 2a and 2b show views of a hand brake and bogie assembly.

Figure 1 shows a simplified schematic representation of a hand brake mechanism. A railway bogie 10 is supported, in part, by an axle 20. The axle has a hand brake lever mechanism 30 on each wheel 22 of the axle 20. In this simplified drawing each lever mechanism includes a brake pad 32, a bell crank

34 and a cable support 36. The lever mechanism is operated by two cables 40 and 50 which are in turn operated by a hand brake actuator 60. The actuator is driven by one of two handwheels 70, 75 on either side of the bogie 10, such that turning of either handwheel in the direction of the arrows A causes the application of the brakes at the wheels 22, and turning of the handwheels in the opposite direction releases the brakes.

Actuator 60 has a screw 62 which is rotatably held in a support 64. The screw is, in this instance, in direct rotary communication with handwheel 70 and is geared to handwheel 75 so that the rotation from the handwheel 75 is reversed, to give the same sense of rotation on each side of the wagon. Rotation of the screw causes a nut 66 to move linearly, in the direction of arrow B when the handwheels are turned in the direction of arrow A, and in the reverse direction when the handwheel rotation is reversed. A yoke 68 is pivotably connected to the nut 66 at a pivot point 67 and the linear movement of the nut

66 causes movement of elements of the cables 40 and 50.

On one side of the screw 62 an inner part 54 of cable 50 is connect to the yoke 68, and an outer sheath 52 of the cable is fixed at support 64. Movement of the nut 66 plus yoke 68 causes the inner part 54 to be pulled in relation to the

sheath and such action causes the corresponding brake mechanism to force the brake pad against the wheel 22.

On the other side of the screw 62 the sheath 42 of cable 40 is fixed to the yoke 68 whilst the end of the inner part 44 of the cable is attached to the support 64 as shown. Movement of the yoke 68 in the direction of arrow B causes the distance between the sheath-bearing yoke 68 and the end of the inner part 44 of cable 40 to increase. This movement of the sheath 42 relative to the fixed inner part 44 causes a corresponding shortening of the distance between the end of the inner part 44 and the sheath at the other end of the cable, which shortening applies the brake to the wheel 22.

Figures 2a and 2b show the hand brake of Figure 1 in more detail when assembled with a railway bogie. Like reference numerals in Figure 1 and 2a/2b refer to like parts. In figures 2a and 2b, on/off indicators 80 are illustrated which are activated by further cables 82 mounted to hand brake mechanisms 30. It is evident from Figures 2a and 2b that there are no intervening lever mechanisms between the actuator 60 and the brake mechanisms 30. Thus, only linear movements take place between the actuator 60 and the brake mechanisms 30. This linear movement is achieved by pushing and pulling of the cables 40 & 50. The cables are rigid in the direction of movement i.e. when pushed or pulled but also laterally resilient so that they can be routed in a non-linear path as shown.

One embodiment only has been described and illustrated but modifications, alternatives, variants etc will be apparent to the skilled addressee.