Patent Description:
Brake calipers of the aforementioned type are generally known in the art and typically employed in trucks or buses. The friction lining of such a brake caliper is configured to bear against a brake disc during braking, which in turn causes the friction lining to wear over time. To monitor the friction lining thickness, in particular to determine whether the thickness of the friction lining is below a predefined wear limit, it is known in the art to arrange a wear indication device proximate to the friction lining.

As the wear, i.e. consumption, of the friction lining caused by the rotation of the brake disc during the brake progresses, at some point a distal portion of the wear indication device will commence to be worn off, i.e. consumed, as well.

Due to that, the distal portion of the wear indication device facing towards the friction lining and/or the brake disc is formed by a material that does not damage the brake disc but withstands high temperatures that occur during braking.

A signal wire is typically integrated in the distal portion of the wear indication device that is subject to wear. Once the wire is being ruptured by the rotation of the brake disc during braking, a voltage change is registered as a function of the rupture, indicating that the wear limit is reached. Only a residual amount of friction lining remains such that the vehicle can safely be taken to a maintenance station for brake pad replacement.

<CIT> shows a wear indication device of the aforementioned type that allows an appropriate wear indication and mounting of the wear indication device to the brake pad carrier. Said wear indication device comprises a fixation means for fixating the signal wire. The fixation of the signal wire to the clip or brake pad basically relies on friction between the signal cable and the clip. Due to the friction-based fixation, it has been found that under certain conditions, the signal wire, in particular the looped portion of the signal wire, may loosen from the fixation means. When this occurs, the signal wire may rupture prematurely, i.e. earlier than intended, by the rotation of the brake disk during braking. In such case, a false or inaccurate indication is generated even before the actual wear limit is reached. This is highly unwanted. Furthermore, it has been observed that with known fixation means, signal wires have been erroneously assembled, for example too tight or too loose. When this happens, the overall accuracy of the wear limit indication is reduced. <CIT> shows a brake caliper of the state of the art comprising:.

It was therefore an object of the present invention to provide a brake caliper that overcomes the above-mentioned issues as far as possible. In particular, it was an object of the invention to provide a brake caliper having a wear indication device that allows a reliable and accurate monitoring and indication of the consumption of the friction lining. Further, it was an object of the invention to.

simplify the mounting of the wear indication device to the brake pad carrier. The invention concerns a brake caliper according to claim <NUM>. The brake caliper comprises a brake pad having a friction lining and a brake pad carrier configured to carry the friction lining proximate to a brake disc of the vehicle brake, wherein the friction lining has a contact surface facing away from the brake pad carrier which is configured to bear against the brake disc of the vehicle brake during braking, and a wear indication device having a fixation means and a signal wire comprising a looped portion, wherein the fixation means has a front part engaging the carrier plane, a back part engaging the rear plane and a bridge connecting the front part and the back part, wherein the looped portion of the signal wire is at least partially arranged externally on the front part of the wear indication device and projects therefrom towards the contact surface. The invention achieves the initially mentioned objects by suggesting a hook that is attached to the back part of the fixation means, wherein said hook is configured for engaging with said looped portion.

The invention advantageously recognized that by providing a hook attached to the back part of the fixation means the signal wire can be conveniently and securely mounted while the looped portion is properly tightened. In this way, the position of the looped portion and the signal wire as such is exactly determined and the looped portion is reliably kept in a defined position. Hence, the likelihood of false i.e. too early wear limit indications is reduced. Furthermore, the overall assembly process of the wear indication device is more repeatable and more mistake-proof.

According to a preferred embodiment, the hook comprises a first portion extending from said back part, wherein said first portion is aligned substantially in parallel to said bridge. Preferably, the hook comprises a second portion extending form the first portion, wherein said second portion is aligned substantially in parallel to the back part and extends towards said bridge. In this way, the looped portion of the signal wire is safely kept in a predefined position while the geometry of said hook supports a convenient assembly of the signal wire with the fixation means. With the help of the second portion, the looped portion is kept in place safely, even in the event of substantial vibrations that may occur during vehicle operation.

According to another preferred embodiment, the fixation means comprises a cut-out located adjacent to said hook, in particular, wherein a geometry of said cut-out corresponds to a geometry of said hook. With the help of said cut-out, the overall weight of the fixation means is reduced, while, in addition, the available mounting space for the looped portion is increased in the proximity of the hook.

According to another preferred embodiment, said hook is formed integrally with said fixation means. In other words, hook and fixation means are preferably manufactured as one-piece and in particular from the same material. In this way, the number of parts and the manufacturing complexity is reduced.

According to yet another preferred embodiment, said looped portion comprises a loop protective sleeve arranged at said looped portion, wherein said loop protective sleeve is configured for protecting the signal wire at a portion at which the signal wire contacts said hook. With the help of said loop protective sleeve, it is ensured that even when some minor relative movement between hook and the looped portion occurs, the contact portion of the signal wire is protected from excessive wear. Preferably, said signal wire comprises a main protective sleeve, wherein said main protective sleeve is configured to abut or to be pressed against said hook to secure the position of the looped portion and wherein said main protective sleeve overlaps with said loop protective sleeve.

According to another preferred embodiment, the fixation means comprises a bar extending from the front part parallel to the carrier plane and wherein the bar is configured to engage the signal wire proximate to the carrier plane. Thus, the signal wire is repeatable secured at a position where it is proximate to the carrier plane and the contact surface such that the signal wire will face towards and come into contact with the brake disc, where it will be ruptured when the predefined wear limit is reached. Preferably, the bar extends at a distance and parallel to the carrier plane. The bar is preferably straight, but may also be partially or completely curved.

According to a preferred embodiment, the brake pad carrier has a recess, in particular a through-hole, wherein said recess extends from the carrier plane to the rear plane, and wherein the signal wire is led there through. Thus, a secure and reliable guidance of the signal wire through the brake pad carrier is achieved. Preferably, the looped portion of the signal wire is at least partially looped around the bar, extends through the recess and is looped around the hook. In this way, the signal wire is safely and repeatable secured to the fixation means.

According to another preferred embodiment, the fixation means has a recess configured to guide the signal wire, wherein the recess at least partially overlaps the recess of the brake pad carrier, and a back end portion of the signal wire is led through both recesses. Thus, the signal wire and, in particular, its back end, can be guided from the rear plane to a connector which can be used to connect wear indication device to a control unit of a vehicle.

It is further preferred that the fixation means has a positioning means configured to engage a circumferential surface of the through-hole, thereby arranging the fixation means at a predefined position with respect to the through hole. Thus, the fixation means is secured parallel to the carrier plane by the positioning means and additionally orthogonal to the carrier plane by the clamping force acting on the carrier plane and the rear plane, respectively. Such a positioning means securely arranges the fixation means with respect to the through-hole and at the same time provides a repeatable positioning of the signal wire which ensures a safe detection of the wear limit.

Preferably, the bridge is configured to rest against an upper surface of the brake pad carrier. Thereby, the fixation means can be coupled to the brake pad carrier by pushing the fixation means from the upper surface of the brake pad carrier along the carrier plane and rear plane into its final position. Thus, the final position of the fixation means with respect to the carrier plane is advantageously secured by the bridge which rests against an upper surface of the brake pad carrier.

For a more complete understanding of the invention, the invention will now be described in detail with reference to the accompanying drawings. The detailed description will illustrate and describe what is considered as a preferred embodiment of the invention. It should of course be understood that various modifications and changes in form or detail could readily be made without departing from the scope of the claims. It is therefore intended that the invention may not be limited to the exact form and detail shown and described herein, nor to anything less than the whole of the invention disclosed herein and as claimed hereinafter. Further, the features described in the description, the drawings and the claims disclosing the invention may be essential for the invention considered alone or in combination. In particular, any reference signs in the claims shall not be construed as limiting the scope of the invention. The wording "comprising" does not exclude other elements or steps. The wording "a" or "an" does not exclude a plurality.

These and other aspects, features and/or technical effects will be apparent from and elucidated with reference to the illustrations described hereinafter, which show in:.

<FIG> shows a disc brake <NUM> that comprises a brake caliper <NUM>, forming an accommodation space for, among others, brake pads <NUM>. Each brake pad <NUM> comprises a brake pad carrier <NUM>, each having and a friction lining <NUM> that comes into contact with the disc of the brake (not shown) during braking in order to apply a braking force.

The brake pad carrier <NUM> extends completely over the inner surface of the brake caliper <NUM> and projects beyond the upper periphery of the brake caliper <NUM>. Each of the brake pad carriers <NUM> has a carrier plane <NUM>, which is configured to carry one of the friction linings <NUM>. The friction lining <NUM> has a contact surface <NUM> facing away from the brake pad carrier <NUM>, which is configured to bear against the brake disc of the vehicle brake <NUM> during braking. The brake pad carrier <NUM> further has a rear plane <NUM> opposite to the carrier plane <NUM>.

Further, the brake pad carrier <NUM> has a wear indication device <NUM> which is configured to assess the degree of wear of the friction lining <NUM>. The wear indication device <NUM> is coupled to the brake pad carrier <NUM> and at least partly received in a recess (not shown) of the friction lining <NUM>. Each of the frictions linings <NUM> has a cut-out <NUM> surrounding the recess (not shown) such that the recess is arranged within the region of the cut-out <NUM>. Thus, the wear indication device <NUM> is surrounded by the frictions lining <NUM> wherein the cut-out <NUM> allows an easy access to the wear indication device <NUM> without requiring demounting of the brake pads <NUM>.

The two brake pad carriers <NUM> each carrying one of the friction linings <NUM> are held in position by a spring hanger <NUM>. The spring hanger <NUM> is preferably connected to the brake caliper <NUM> by a spring hanger seat <NUM> on one side and by a spring hanger fixation means <NUM> on the other side. After releasing the spring hanger fixation means <NUM> and guiding the spring hanger <NUM> out of its seat <NUM>, the spring hanger <NUM> may be removed. When the spring hanger <NUM> is removed, the brake pads <NUM> may be removed likewise and be exchanged. The wear indication device <NUM> has a fixation means <NUM> and a signal wire <NUM> comprising a connector <NUM> at its distal end.

<FIG> details the wear indication device <NUM>. In <FIG>, said wear indication device <NUM> is shown in an assembled state. <FIG> and <FIG> illustrate the different assembly steps. Subsequently, different parts of the wear indication device <NUM> will be explained with reference to <FIG>.

The wear indication device <NUM> comprises a fixation means <NUM> and a signal wire <NUM>. The signal wire <NUM> comprises a looped portion <NUM>. The fixation means <NUM> has a front part <NUM> engaging the carrier plane <NUM>. The fixation means <NUM> furthermore comprises a back part <NUM> engaging the rear plane <NUM>. The fixation means <NUM> furthermore comprises a bridge <NUM> which connects the front part <NUM> to the back part <NUM>. The looped portion <NUM> of the signal wire <NUM> is at least partially arranged externally on the front part <NUM> of the wear indication device <NUM>. The looped portion <NUM> projects therefrom towards the contact surface <NUM>.

The fixation means <NUM> comprises a hook <NUM>. The hook <NUM> is attached to the back part <NUM> of the fixation means <NUM>. The hook <NUM> is configured for engaging with said looped portion <NUM>. The hook <NUM> comprises a first portion <NUM>. The first portion extends from the back part <NUM> and is aligned substantially in parallel to said bridge <NUM>. The hook <NUM> further comprises a second portion <NUM> that extend from the first portion <NUM>. The second portion <NUM> is aligned substantially in parallel to the back part <NUM> and extends towards said bridge <NUM>.

The fixation means <NUM> comprises a cut-out <NUM>. The cut-out <NUM> is located adjacent to the hook <NUM>. A geometry of the cut-out <NUM> corresponds to a geometry of the hook <NUM>.

The hook <NUM> is formed integrally with the fixation means <NUM>. The signal wire <NUM> comprises a main protective sleeve <NUM>. The main protective sleeve <NUM> is arranged adjacent to the looped portion <NUM>. The main protective sleeve <NUM> is configured to be pressed or abutted against the hook <NUM> to secure the position of looped portion <NUM>. The Looped portion <NUM> comprises a loop protective sleeve <NUM> for protecting the signal wire <NUM> at a contact portion <NUM> at which the signal wire <NUM> contacts the hook <NUM>.

The fixation means <NUM> comprises a bar <NUM>. The bar <NUM> extends from the front part <NUM> and in parallel to the carrier plane <NUM>. The bar <NUM> is configured to engage the signal wire <NUM> proximate to the carrier plane <NUM>. The brake pad carrier <NUM> has a recess <NUM>, which is configured as a through-hole <NUM>. The recess <NUM> extends from the carrier plane <NUM> to the rear plane <NUM>. The signal wire <NUM>, in particular the looped portion <NUM>, is led through the recess <NUM>. The looped portion <NUM> of the signal wire <NUM> is at least partially looped around the bar <NUM>. The looped portion <NUM> extend through the recess <NUM> and is looped around the hook <NUM> in the assembled state, which is shown in <FIG>.

The fixation means <NUM> has a recess <NUM>. The recess <NUM> is configured to guide the signal wire <NUM>, wherein the recess <NUM> at least partially overlaps the recess <NUM> of the brake pad carrier <NUM>. A back end portion <NUM> of the signal wire <NUM> is led through both recesses <NUM>, <NUM>. The fixation means <NUM> further has a positioning means <NUM> configured to engage a circumferential surface of the through-hole <NUM>. Thereby, the fixation means <NUM> is arranged at a predefined position with respect to the through-hole <NUM>. The bridge <NUM> is configured to rest against an upper surface <NUM> of the brake pad carrier <NUM>.

In <FIG>, the wear indication device <NUM> is shown in an assembled state at which the fixation means <NUM> engages the brake pad carrier <NUM> and wherein the looped portion <NUM> of the signal wire <NUM> is looped around the bar <NUM>, extends through the recess <NUM> and is also looped around the hook <NUM> in order to secure the position of the signal wire <NUM> with respect to the brake pad carrier <NUM>.

<FIG> shows an initial assembly step at which the looped portion <NUM> is guided through the recess <NUM> of the brake pad carrier <NUM> such that the looped portion <NUM> extends through the recess <NUM>. Thereafter, fixation means <NUM> is lowered towards the brake pad carrier <NUM> such that the bar <NUM> engages the looped portion <NUM>. As shown in <FIG>, the back end <NUM> of the looped portion <NUM> is furthermore guided through the recess <NUM> of the wear indication device <NUM>. As a final step, indicated with the arrow in <FIG>, the back end <NUM> of the looped portion <NUM> is put over the hook <NUM> in order to safely secure the signal wire <NUM> as shown in <FIG>.

<FIG> and <FIG> show an embodiment of the fixation means <NUM> in perspective views. With regard to a more detailed description, reference is made to the corresponding description of <FIG>.

Claim 1:
Brake caliper (<NUM>) for a vehicle brake (<NUM>), in particular for a disc brake of a commercial vehicle, the brake caliper (<NUM>) comprising:
- a brake pad (<NUM>) having a friction lining (<NUM>) and a brake pad carrier (<NUM>) configured to carry the friction lining (<NUM>) proximate to a brake disc of the vehicle brake (<NUM>),
wherein the friction lining (<NUM>) has a contact surface (<NUM>) facing away from the brake pad carrier (<NUM>) which is configured to bear against the brake disc of the vehicle brake (<NUM>) during braking,
wherein the brake pad carrier (<NUM>) has a carrier plane (<NUM>) facing towards the friction lining (<NUM>) and a rear plane (<NUM>) opposite to the carrier plane (<NUM>), and
- a wear indication device (<NUM>) having a fixation means (<NUM>) and a signal wire (<NUM>) comprising a looped portion (<NUM>),
wherein the fixation means (<NUM>) has a front part (<NUM>) engaging the carrier plane (<NUM>), a back part (<NUM>) engaging the rear plane (<NUM>) and a bridge (<NUM>) connecting the front part (<NUM>) and the back part (<NUM>),
characterised in that the looped portion (<NUM>) of the signal wire (<NUM>) is at least partly arranged externally on the front part (<NUM>) of the wear indication device (<NUM>) and projects therefrom towards the contact surface (<NUM>),
wherein a hook (<NUM>) is attached to the back part (<NUM>) of the fixation means (<NUM>), said hook (<NUM>) being configured for engaging with said looped portion (<NUM>).