GB2114691A - Brake linings - Google Patents

Abstract

There is disclosed a brake lining holder for a rail vehicle brake system which comprises a main holder 1, a backing plate 3 for mounting a brake lining (5) (Figure 2) and which is adapted for detachable mounting on the holder 1, first and second spaced- apart mounting pins (19) provided on the holder 1, first and second open- ended mounting sockets 25, 23 provided on the backing plate 3 to engage with the first and second mounting pins (19) respectively in order to mount the backing plate 3 on the holder 1, and a retaining spring arrangement for maintaining the backing plate 3 in its mounted position on the holder 1. The first open-ended mounting socket 25 is engageable with at least half of the outer circumference of the first mounting pin (19) and the second open-ended mounting socket 23 is engageable with a smaller proportion of the circumference of the second mounting pin (19). The retaining spring arrangement is engageable with a portion 37 of the backing plate 3 at a position such that the spring 29 applies a restoring action to the backing plate 1 having a longer lever arm with respect to the first mounting socket 25 than the lever arm with respect to the second mounting socket 23. <IMAGE>

Description

SPECIFICATION A brake lining holder This invention relates to a brake lining holder comprising a main holder member, a backing plate member for mounting a brake lining and which is adapted for detachable mounting on the holder member, first and second spaced-apart mounting pins provided on one of said members, first and second open-ended mounting sockets provided on the other of said members to.engage with the first and second mounting pins respectively in order to mount the backing plate member on the holder member, and a retaining spring arrangement for maintaining the backing plate in its mounted position on the holder member.

There are known brake lining holders which have on both their longitudinal ends bearing pins used to receive bearing eyes of a backing plate; the bearing eyes are either closed with arrangements of this type so that exchange of the backing plate carrying the brake lining is made possible by pulling out the bearing pins, or the bearing eyes of the backing plate are constructed as substantially quarter shell depressions, which, when the backing plate is applied, surround the associated bearing pin of the brake lining holder only at a specific area of its circumference. In addition, there is provided a retaining- or tensioning spring arranged rotatably on the brake lining holder, which acts on an extension or flange distant from the backing plate, in order to fix and maintain the backing plate in its applied position on the bearing pin of the brake lining holder.The flange or holding lug used to install the retaining spring is arranged to be absolutely symmetrical to the two bearing eyes, so that the cohesive forces are respectively the same, independent of the direction of rofation of the brake disc to be braked.

The necessary holding force, which is applied by a bow-shaped retaining spring, increases greatly, however, with the increase in the lining surface and with increasing surface pressure of the lining, i.e. the lining has the tendency to "travei up" the brake disc.

Proceeding from this, this present invention has been developed primarily, though not exclusively, with a view to so develop a brake lining holder of the type mentioned above, that during use of components of the brake that are substantially the same, greater holding forces can be applied independently of the direction of rotation of the brake disc to be braked.

According to the invention there is provided a brake lining holder comprising a main holder member, a backing plate member for holding a brake lining and which is adapted for detachable mounting on the holder member, first and second spaced-apart mounting pins provided on one of said members, first and second open-ended mounting sockets provided on the other of said members to engage with the first and second mounting pins respectively in order to mount the backing plate member on the holder member, and a retaining spring arrangement for maintaining the backing plate member in its mounted position on the holder member;; in which the first open-ended mounting socket is engageable with at least half of the outer circumference of the first mounting pin and the second open-ended mounting socket is engageable with a smaller proportion of the outer circumference of the second mounting pin; and the retaining spring arrangement is engageable with a portion of the backing plate member at a position such that the spring arrangement applies a restoring action to the backing plate having a longer lever arm with respect to the first mounting pin and first mounting socket than the lever arm with respect to the second mounting pin and second mounting socket when the backing plate member is mounted on the holder member.

Therefore, when a brake lining holder according to the invention is used with a brake disc, regardless of the direction of rotation of the brake disc, there are applied holding,forces to the backing plate which act so as to prevent the tendency for the brake lining to travel with the rotating brake disc. For one direction of rotation of the brake disc, increased holding forces acheived by virtue of the longer lever arm which is provided for restoring action of the spring arrangement with respect to the first mounting pin and first mounting socket, than the lever arm with respect to the second mounting pin and second mounting socket.With respect to the opposite direction of rotation, this is resisted by virtue pf the manner by which the first mounting socket engages with the first mounting pin i.e. an engagement through at least half of the outer circumference of the first mounting pin.

Thus, for the one direction of rotation of the brake disc, there will be a tendency for the backing plate to pivot about the pivot axis provided between the first mounting pin and the first mounting socket, but this will be resisted strongly by the long lever arm for the retaining spring arrangement. Opposite rotation of the brake disc will tend to cause the backing plate to pivot about the pivot axis provided by the second mounting pin and the second mounting socket, but this will be resisted by virtue of the engagement between the first mounting pin and the first mounting socket, which, as mentioned above, extends throughout at least half of the outer circumference of the first mounting pin.

Therefore, the fact that the retaining spring arrangement has a smaller lever arm with respect to this latter condition does not matter, in view of the strong resistance to pivoting which is provided by the engagement between the first mounting pin and the first mounting socket.

The first mounting socket provides, effectively, an extension which enables the first mounting pin to be embraced by the socket, so that reaction forces are supported in a substantially radially inwards manner with respect to the middle point of the brake disc.

One embodiment of brake lining holder according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view of a brake lining holder, on which a backing plate carrying a brake lining is shown in dot-dash lines in different positions between a disengaged position and a mounted position on the holder; Figure 2 is a detailed rear view of the brake lining and the baking plate; Figure 3 is a partial sectional view of half of the brake lining holder; and Figure 4 is a sectional view taken on the line IV--IV in Figure 1.

In Figure 1 of the drawing there is shown a brake lining holder 1. This is used for the holding of a backing plate 3 with a brake lining 5, which is described below. The backing plate 3 with the brake lining 5 secured to it is shown in dot-dash line in Figure 1 in different positions relative to the brake lining holder 1. The brake lining holder, which together with the brake lining forms the actual brake shoe, is in known way equipped with ribs 7, with bearing eyes 9 and with a pin 11 extending through the bearing eyes. On the pin 11 there is pivoted in known manner a bracing element (not shown). According to Figure 1 there is further fitted on the brake lining holder 1 a guide rod 1 3 which is used for holding the brake shoe relative to the brake disc 1 5.The guiding of the brake lining of the following described construction is, however not limited to the embodiment of pin 11 or guide rod 1 3 shown by way of example i.e. the holding of the lining can also be used with other guide-and actuation systems of the brake lining holdels.

On the side of the brake lining holder turned towards the brake disc 1 5 (Figure 3) with which the brake holder is to be used there is provided, on both the longitudinal ends of the same, a mounting pin 19 with a pin head 21. The two pins are used to support first and second open-ended mounting sockets in the form of bearing eyes 25 and 24 provided on the backing plate when the brake lining is set on the brake lining holder. The two bearing eyes of the backing plate 3 are of different shape or contouring, whereby the bearing eye 23 shown on the left of Figure 1 is constructed as a so-called half shell.

The bearing eye 23 is accordingly more open than the bearing eye 25 and encloses the associated pin 19 on a smaller part of the circumference than the bearing eye 25.

On the brake lining holder (Figure 1 and 3) there is further provided a bearing eye 27 which extends for example on the passage to one of the ribs 7 and is used for the rotatable mounting of a retaining spring 29. The retaining spring 29 has, for this purpose, a curved end piece 31 which extends through the bearing eye 27 shown on the left hand side and is secured against falling out with the aid of a spiit pin or similar securing means.

The end opposite the bearing eye 27 is curved round according to the representation if Figure 1 more or less in the direction of the brake lining holder and can partially enclose a further bearing eye 33. The bearing eye is also used at the same time for the rotatabie mounting of a clamping device in the form of a holding jack 35 which, when the retaining spring 29 is in the closed state, can be rotated from the position shown in dotted lines in Figure 1 into the position shown in solid lines, and in this way the retaining spring can be locked into its engaged position. On the holding jack any securing elements at all can be provided which prevent automatic release of the holding system.

The retaining spring 29 is used to overlap a holding lug 37 of the backing plate 3 in the way that can be seen in Figures 1 and 4, when the backing plate carrying the brake lining assumes its assembly position on the brake lining holder 1, i.e. when the bearing eyes 23 and 25 respectively surround the associated pins 1 9. The holding lug 37 juts out at an angle from the backing plate 3 in the direction towards the brake lining holder 1, as is shown in Figure 4, whereby the position of the holding lug 37, based on the centre position of the pin 11, is unsymmetrical. Figures 1 and 2 show that the holding lug 37 is displaced approximately in the direction of the bearing eye 23, and so the retaining spring 29 also lies on the holding lug 37 with corresponding displacement.

The method of operation of the abovedescribed brake lining holding is as follows.

If the brake shoe is to be assembled i.e. if the brake lining fixed on the backing plate is to be connected to the brake lining holder 1, then first of all, with appropriate angular adjustment (see Figure 1) the bearing eye 25 is laid on the pin 19 at right hand side. The corresponding longitudinal movements of the backing plate are shown on the right hand side of Figure 1. After placing the bearing eye 25, the backing plate is pivoted in an anti-clockwise direction (Figure 1) for the purpose of assembly, until the quarter shell-shaped bearing eye 23 surrounds its pin 19. During this insertion of the backing plate, the retaining spring 29 is held in the open position that is shown in dot-dash line in Figure 1. After insertion of the backing plate the retaining spring 29 is held in the open position that is shown in dot-dash line in Figure 1. After insertion of the backing plate the retaining spring 29 can be pivoted into the position shown in Figure 1 in solid lines, and can be secured with the aid of the holding jack 35 or similar securing element. The retaining spring lies in a position-blocking manner on the upper side of the angularly jutting-out holding lug 37, and thereby pivoting movement of the backing plate and the lining in the clockwise direction is now blocked. This is the assembly position of the brake on the brake lining holder.

The advantageous method of operation of the brake lining holder is also independent of the direction of rotation of the brake disc 1 5. If the brake disc, indicated in dot-dash line in Figure 1 is rotated in the clockwise direction (according to Figure 1), then the brake forces acting on the brake lining try to rotate the backing plate in the clockwise direction about the bearing eye 25 or the pin 1 9 receiving the bearing eye. Since the holding lug 37 is arranged to be off centre, i.e.

offset in the direction of the bearing eye 23, then the holding force or restoring action exerted by the retaining spring 29 works over a correspondingly longer lever than if the holding lug were arranged in the middle. Accordingly, larger forces can be supported by the retaining spring 29, which means that the backing plates with greater brake lining surfaces can be assembled on the brake lining holder without greater dimensioning being necessary for the retaining spring or the holding jack.

If the brake disc is rotated in counter-clockwise direction, then the braking forces having an effect on the brake lining are received directly in the region of the (more closed) bearing eye 25, i.e. by the extension 39 of the same, since this extension is made to be longer than the corresponding extension of the bearing eye 23. In other words, the extension 39 of the bearing eye 25 encloses the pin 1 9 over a greater circumference so that the brake forces operating go directly into the pin 19.

Accordingly, there is disclosed herein a brake lining holder which comprises a main holder member 1, a backing plate member 3 for mounting a brake lining 5 and which is adapted for detachable mounting on the holder member 1, first and second spaced-apart mounting pins 19 provided on one of the members 1, 3, first and second open-ended mounting sockets 25, 23 provided on the other of the members 1, 3, to engage with the first and second mounting pins respectively in order to mount the backing plate member 3 on the holder member 1, and a retaining spring arrangement 29 for maintaining the backing plate member 3 in its mounted position on the holder member 1.While it is preferred that the first and second mounting pins 19 be provided on the main holder member 1, and the first and second mounting sockets 25, 23 be provided on the backing plate member 3, it is within the scope of this invention for the pins and the sockets to be reversed i.e. the mounting pins provided on the backing plate member 3 and the mounting sockets provided on the holder member 1.

The first open-ended mounting socket 25 is engageable with at least half of the outer circumference of the corresponding first mounting pin 1 9 and the second open-ended mounting socket 23 is engageable with a smaller proportion of the outer circumference of the second mounting pin 19. The retaining spring arrangement 29 is engageable with a portion 37 of the backing plate member 3 at a position such that the spring arrangement applies a restoring action to the backing plate member 1 having a longer lever arm with respect to the first mounting pin 19 and the first mounting socket 25 than the lever arm with respect to the second mounting pin 1 9 and the second mounting socket 23.

Claims (7)

1. A brake lining holder comprising a main holder member, a backing plate member for holding a brake lining and which is adapted for detachable mounting on the holder member, first and second spaced-apart mounting pins provided on one of said members, first and second open-ended mounting sockets provided on the other of said members to engage with the first and second mounting pins respectively in order to mount the backing plate member on the holder member, and a retaining spring arrangement for maintaining the backing plate member in its mounted position on the holder member; in which the first open-ended mounting socket is engageable with at least half of the outer circumference of the first mounting pin and the second open-ended mounting socket is engageable with a smaller proportion of the outer circumference of the second mounting pin;; and the retaining spring arrangement is engageable with a portion of the backing plate member at a position such that the spring arrangement applies a restoring action to the backing plate having a longer lever arm with respect to the first mounting pin and first mounting socket than the lever arm with respect to the second mounting pin and second mounting socket when the backing plate member is mounted on the holder member.

2. A brake lining holder according to claim 1, in which the first open-ended mounting socket takes the form of a substantially half-shell shape, and the second open-ended mounting socket takes the form of a substantially quarter-shell shape, the arrangement being such that the backing plate member is mounted in position by engaging the first socket on the first mounting pin and then pivoting the backing plate member about the first 'mounting pin until the second mounting socket comes into engagement with the second mounting pin.

3. A brake lining holder according. to claim 1 or 2, in which said portion of the backing plate member comprises a holding lug which projects from the general plane of the backing plate member and towards the holder member, and the retaining spring arrangement comprises a retaining spring which is pivotally mounted on the holder member for movement between a release position and a position of engagement with the holding lug in order to maintain the backing plate member in its mounted position on the holder member.

4. A brake lining holder according to claim 3, including a releasable clamping device engageable with the retaining spring in order to hold the latter in its engaged position.

5. A brake lining holder according to any one of the preceding claims, in which the first and second mounting pins are provided on the holder member, and the first and second open-ended mounting sockets are provided on the backing plate member.

6. A brake lining holder according to claim 1 and substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

7. A rail vehicle brake system including a brake lining holder according to any one of the preceding claims.