GB2177766A - Brake element holder - Google Patents

Abstract

A disc brake pad holder (11) has a dovetail guide for a brake pad (13), the guide being closed at one end by a closure bar having two arms (15, 16) of different length. The longer arm (15) is mounted to be longitudinally displaceable in a guide groove transversely to the dovetail guide and a resiliently biassed pin (20) locks the bar in a closing position by engaging behind a locking surface (18) extending perpendicularly to the direction of movement of the bar. The shorter arm (16) of the bar has an inclined cam surface for engaging and displacing the pin (20) against bias of a spring during movement of the bar towards the closing position. The bar may be removed by engaging knob (24) and displacing the pin against its spring bias. Where the pin is suitably orientated the spring may be omitted. <IMAGE>

Description

SPECIFICATION Brake element holder The present invention relates to a brake element holder, in particular for a disc brake of, for example, a rail vehicle.

In a brake element holder disclosed in DE OS 20 16 674, a brake element locking bar has a limb of resilient material and a pin is resiliently pressed into a bore in the holder for retention of the bar in locking position. Also disclosed is a securing bar which stands under spring pressure and which drops into grooves arranged at the locking bar. Both constructions have, in operation, shown disadvantages in that on the one hand the resilient materiai of the limb can fracture so that the locking bar no longer remains closed and on the other hand the bar can be pressed out of the grooves. The grooves cannot be made sufficiently deep to overcome this danger because the locking bar would otherwise be unduly weakened, which is also disadvantageous.

In the case of a holder disclosed in DE-OS 20 36 107, the locking bar is secured in locking position by a screw firmly screwed in or by a cotter or split pin. However, this has the consequence that the holders, often located in inaccessible places, are difficult to open when worn brake pads are to be replaced and thus the working times for such replacement become too long.

It would thus be desirable for such a bar to be openable relatively easily, but also secure against opening on its own, such security being important for safety. The lock should also be as secure as possible against incorrect use and should be usable for brake element holders at inaccessible places.

According to the present invention there is provided a brake element holder comprising a body provided with a dovetail guide for a dovetail portion of a brake element, a closure bar movable into and out of a closing position in which an arm thereof closes the guide for retention of such dovetail portion, and a displaceable locking pin biassed into a locking position in which it is engageable with a locking surface of the bar to resist movement of the bar out of the closing position, the bar being provided with a cam surface portion cooperable with the pin to displace the pin out of the locking position during movement of the bar into the closing position and the pin being arranged to displace back into the locking position when the bar has reached the closing position.

In a preferred embodiment, the dovetail guide for a brake pad is closed off at one end by a bar consisting of two arms of different length, wherein at least the longer arm is longitudinally displaceable in a guide groove transversely in front of the dovetail guide or the bar can be pivoted about an axis or be displaced perpendicularly to the holder. The bar at its rearward end has a locking surface extending perpendicularly to a given direction of movement of the bar and the arm which is not guided in the guide groove, or the bar itself, has an inclined ramp surface for the pin.

The pin is pressed under the pressure of a spring against the bar and drops in behind the locking surface when the bar is dosed.

Advantageously, the bar is arranged at a lower end of the holder.

Expediently, the pin drops in by only one half as lug behind the locking surface and bears by a support surface against the bar.

In this arrangement it is advantageous that, if the bar is mounted at the lower end of the holder, the pin can no longer detach even when the spring is broken, so that the lock can no longer open on its own. Even in the case of a holder mounted at an inaccessible place, the pin may be able to be detached relatively easily, whereupon the bar can be displaced easily. The pin can drop behind the bar on its own without having to be manipulated on closing of the bar.

Moreover, the holder can have a quite narrow overall shape which makes it possible to be mounted at a rail vehicle wheel where the brake disc lies within the wheel.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a view from below of a brake pad holder showing a closure bar thereof in the closing position, the view being on the section line of Fig. 2; and Figure 2 is a plan view of the holder as shown in Fig. 1.

Referring now to the drawings, there is shown a brake pad holder 11 provided with a dovetail guide 12 for a brake pad 13. Extending transversely to the guide 12 and disposed directly in front of this and at a lower end of the holder is a groove 14, in which one arm 1 5 of a closing bar, consisting of two arms 15 and 16, is displaceably engaged. In the setting illustrated in Fig. 1, the arm 15 of the bar closes off the guide 12 and thereby locks the brake pad 13 firmly in the holder 11. The rearward end 17 of the bar has a locking surface 18 which extends perpendicularly to the bar and perpendicularly to the direction of movement of the bar.

That arm 16 of the bar, which does not lie in the groove 14, is substantially shorter than the arm 15, for example only half or one third of the length of the arm 15. The two arms 15 and 16 together define a U-shape and an inclined ramp surface 19 is arranged on the arm 16.

A locking pin 20 is arranged at the holder 11 to be displaceable and extending parallelly to the holder 11. The pin 20 is pressed by a spring 21 against the bar, wherein the part of the pin 20 which lies against the bar is halved and forms a support surface 22 by which the pin 20 rests laterally against the bar, while the lug 25 of the pin 20 engages behind the surface 18. The lug 23 is oblique at its end.

In the drawings, the bar is illustrated in the closing position, in which the arm 15 closes off the guide 12 so that the brake pad 13 is firmly held in the holder 11. In order to prevent opening of the bar, the lug 23 of the pin 20 lies behind the locking surface 18 of the bar and also bears by its support surface 22 against the bar.

For opening of the lock, the pin 20 is moved by a handle 24 thereof against the force of the spring 21 until the bar is free and can be displaced towards the right in the groove 14. If the bar is pivotable or displaceable perpendicularly to the plane of the holder, then the pin 20 must be raised until the bar can be pivoted or displaced.

For closing of the bar after introduction of the pad 13 into the guide 12, the bar is sim piy displaced towards the left or pivoted in or displaced. In that case, the ramp surface 19 presses the pin 20 at its lug 23 into the open setting and the lug 23 slides over the arm 16 or the bar itself until it drops in behind the locking surface 18 at the bar and thereby arrests the bar in its closing position. The pin 20 then bears by its support surface 22 against the bar. When the lock is mounted at the lower end of a holder 11, the spring 21 of the pin 20 can even be omitted without the lock being able to open on its own. The function remains fully maintained.

Claims (10)

1. A brake element holder comprising a body provided with a dovetail guide for a dovetail portion of a brake element, a closure bar movable into and out of a closing position in which an arm thereof closes the guide for retention of such dovetail portion, and a displaceable locking pin biassed into a locking position in which it is engageable with a locking surface of the bar to resist movement of the bar out of the closing position, the bar being provided with a cam surface portion cooperable with the pin to displace the pin out of the locking position during movement of the bar into the closing position and the pin being arranged to displace back into the locking position when the bar has reached the closing position.

2. A holder as claimed in claim 1, wherein the arm is longitudinally slidable in a groove extending transversely of the guide.

3. A holder as claimed in claim 1, wherein the bar is pivotably movable into and out of the closing position.

4. A holder as claimed in claim 1, wherein the bar is movable into and out of the closing position perpendicularly to the plane of a brake element support face of the body.

5. A holder as claimed in claim 1, wherein the bar comprises a further arm shorter in length than the first-mentioned arm, the cam surface portion being provided on the further arm.

6. A holder as claimed in any one of the preceding claims, wherein the locking surface of the bar extends perpendicularly to a given direction of movement of the bar out of the closing position.

7. A holder as claimed in any one of the preceding claims, wherein the bar is arranged at a part of the holder which, in an intended mounting orientation thereof, is lowermost.

8. A holder as claimed in any one of the preceding claims, wherein the pin is provided at free end portion thereof with a rebate defining flats for engagement with side and end faces of the bar.

9. A holder as claimed in any one of the preceding claims, wherein the holder body is elongate and the pin extends parallel to the longitudinai axis of the body.

10. A brake element holder substantially as hereinbefore described with reference to the accompanying drawings.