This invention relates generally to devices and assemblies for reducing the drag of a friction pad on a rotor, and in particular, to improved friction pad spreading devices, assemblies including the same and methods of mounting the pad spreading devices, all of which lends themselves to a more universally usable and advantageous construction, implementation and installation.
Friction pad spreading devices are known to reduce drag of a friction pad on the rotor of a disc brake assembly. For example, the reduction of drag on the rotor (i.e. the reduction of unwanted friction between the rotor and the friction pad after a braking operation is completed) can provide for increased gas mileage and longer life of the friction pads, two very desirable objectives, especially when brake repairs and/or gas prices are high. Ideally, when the brake pedal is released, the friction pads should spread apart from one another to prevent unwanted and/or undesirable frictional engagement with the rotor. To accomplish this, it is known to provide the disc brake assembly with one or more springs for moving the brake shoes apart from one another when the brake pedal is released.
One example of such a retractor clip is described in U.S. Pat. No. 5,549,181. It is noted that this patent appears to describe yet additional patents that may describe disc brake assemblies that include retraction spring structures.
However, it is believed that deficiencies still exist in the state of the art. For example, the aforementioned '181 patent describes the need for a particular structure that requires carefully aligned apertures and fasteners, which makes for a less than interchangeable and universally adaptable and useable arrangement. That is, the '181 patent, as just one example, requires a specifically designed retractor clip for the particular brake assembly configuration illustrated.
In view thereof, it has been discovered that still further developments in the art are desirable. For example, it would be quite advantageous to provide a pad spreader that can be more universally used with various constructions of disc or other types of brake assemblies. Such a pad spreading device would significantly reduce the cost of wear on the friction pads, increase gas mileage and provide manufacturers and after market third parties with an improved way to achieve the foregoing for their customers.
It has thus been discovered that improved pad spreading devices and assemblies formed thereby are achievable and provided by the present invention, and it is further believed that the present invention overcomes the perceived deficiencies in the prior art as well as provides the objectives and advantages set forth above and below.
Therefore, it is an object and advantage of the present invention to provide an improved friction pad spreading device that overcomes the perceived deficiencies in the prior art.
It is a further object and advantage of the present invention to provide an improved methodology of installing a friction pad spreading device into a braking assembly.
It is a further object and advantage of the present invention to provide an improved friction pad spreading device that operates effectively over the life of the friction pad, thereby providing sufficient compression and restoring forces regardless of the wear upon the friction pad.
It is another object and advantage of the present invention to provide an improved friction pad spreading device that can provide for increased gas mileage and prolonged life of the braking pad, just to name but a few advantageous results.
Further objects and advantages of this invention will become more apparent from a consideration of the drawings and ensuing description.
The invention accordingly comprises the features of construction, combination of elements, arrangement of parts and sequence of steps that will be exemplified in the disclosure hereinafter set forth, and the scope of the invention will be indicated in the claims.
To overcome the perceived deficiencies in the prior art and to achieve the objects and advantages above and below, the present invention in a first preferred embodiment, is generally speaking, directed to a friction pad drag reduction assembly for reducing drag between a rotor and at least a first friction pad of a first braking subassembly that itself also comprises a first backing plate, wherein the first backing plate comprises a first end and a second end, wherein the assembly comprises a second braking subassembly comprising a second friction pad in facing alignment with the rotor, and a second backing plate to which the second friction pad is coupled, the second backing plate having a first end and a second end; a caliper bracket that slidably supports, on a first side thereof, the first end of the first backing plate and the first end of the second backing plate, and, on a second side thereof, the second end of the first backing plate and the second end of the second backing plate; a first pad spreader, comprising a loop section and at least a first end and a second end, wherein the first end engages the first end of the first backing plate and the second end engages the first end of the second backing plate; a second pad spreader, comprising a loop section and at least a first end and a second end, wherein the first end engages the second end of the first backing plate and the second end engages the second end of the second backing plate; wherein the first and second spreaders are secured to the assembly by (i) only the first and second ends of each pad spreader or (ii) the first and second ends of each pad spreader along with the respective loop sections of both the first pad spreader and the second pad spreader being snap fit onto the caliper bracket; wherein upon an application of a braking force, the assembly urges the first friction pad of the first braking subassembly and the second friction pad of the second braking subassembly towards the rotor; and upon a removal of the braking force, the first and second pad spreaders urge the first friction pad of the first braking subassembly and the second friction pad of the second braking subassembly away from the rotor.
In a specific embodiment, the caliper bracket includes a first guide rail and a second guide rail, wherein the first end of the first backing plate is slidable along the first guide rail and the second end of the first backing plate is slidable along the second guide rail, and the first end of the second backing plate is slidable along the first guide rail and the second end of the second backing plate is slidable along the second guide rail, the first end of the first pad spreader is in pressing engagement against the first end of the first backing plate and the second end of the first pad spreader is in pressing engagement against the first end of the second backing plate; the first end of the second pad spreader is in pressing engagement against the second end of the first backing plate and the second end of the second pad spreader is in pressing engagement against the second end of the second backing plate; and the loop sections of both the first and second pad spreaders are snap fit onto the caliper bracket.
In another specific embodiment, the caliper bracket includes a first guide rail and a second guide rail, wherein the first end of the first backing plate is slidable along the first guide rail and the second end of the first backing plate is slidable along the second guide rail, and the first end of the second backing plate is slidable along the first guide rail and the second end of the second backing plate is slidable along the second guide rail, the first end of the first pad spreader is in pressing engagement against the first end of the first backing plate and the second end of the first pad spreader is in pressing engagement against the first end of the second backing plate; the first end of the second pad spreader is in pressing engagement against the second end of the first backing plate and the second end of the second pad spreader is in pressing engagement against the second end of the second backing plate; and the loop sections of both the first and second pad spreaders are not snap fit to the caliper bracket.
In yet another specific embodiment, the caliper bracket includes a first slot and a second slot, wherein the first end of the first backing plate is slidable within the first slot and the second end of the first backing plate is slidable within the second slot, and the first end of the second backing plate is slidable within the first slot and the second end of the second backing plate is slidable within the second slot, the first end of the first pad spreader is in pressing engagement against the first end of the first backing plate and the second end of the first pad spreader is in pressing engagement against the first end of the second backing plate; the first end of the second pad spreader is in pressing engagement against the second end of the first backing plate and the second end of the second pad spreader is in pressing engagement against the second end of the second backing plate; and the loop sections of both the first and second pad spreaders are snap fit onto the caliper bracket.
In yet another specific embodiment, the caliper bracket includes a first slot and a second slot, wherein the first end of the first backing plate is slidable within the first slot and the second end of the first backing plate is slidable within the second slot, and the first end of the second backing plate is slidable within the first slot and the second end of the second backing plate is slidable within the second slot, the first end of the first pad spreader is in pressing engagement against the first end of the first backing plate and the second end of the first pad spreader is in pressing engagement against the first end of the second backing plate; the first end of the second pad spreader is in pressing engagement against the second end of the first backing plate and the second end of the second pad spreader is in pressing engagement against the second end of the second backing plate; and the loop sections of both the first and second pad spreaders are not snap fit to the caliper bracket.
And yet in another specific embodiment, the caliper bracket includes a first slot and a second slot, wherein the first end of the first backing plate is slidable within the first slot and the second end of the first backing plate is slidable within the second slot, and the first end of the second backing plate is slidable within the first slot and the second end of the second backing plate is slidable within the second slot, the first end of the first pad spreader wraps around the first end of the first backing plate and the second end of the first pad spreader wraps around the first end of the second backing plate; the first end of the second pad spreader wraps around the second end of the first backing plate and the second end of the second pad spreader wraps around the second end of the second backing plate; and the loop sections of both the first and second pad spreaders are not snap fit to the caliper bracket.
In other preferred embodiments, the invention is directed to pad spreaders for use in such friction pad drag reduction assemblies.
In yet other preferred embodiments, the present invention is directed to methods of assembling such friction pad drag reduction assemblies.
The above set forth and other features of the invention are made more apparent in the ensuing Description of the Preferred Embodiments when read in conjunction with the attached Drawings, wherein:
Like numbers to identify like parts and features will be used among the various figures, but not all features will be specifically identified in each illustration.
Reference is first made generally to
For convenience, the various disc-brake assemblies will be generally indicated at 10, notwithstanding the various differences between them, all of which would be fully recognized by one skilled in the art. However, to appreciate the present invention, certain references to these figures will first be made. Generically, reference to “assembly 10” is intended to indicate that the present invention is equally applicable to all the disc brake assemblies disclosed herein.
By way of general background, it is well known to those skilled in the art that disc brake assemblies generally, and the embodiments disclosed herein, are used to stop a rotatable disc (i.e. rotor) 15, which rotates with the axle of a wheel to be braked. Assemblies 10 can be seen to include opposing braking subassemblies 17, 18, each of which preferably comprise a steel backing plate 20, a friction pad 25 mounted on the side of backing plate 20 facing rotor 15, and a shim 30 on the opposite side of backing plate 20. As will be discussed in greater detail below, the two backing plates 20 may be slidably mounted on guide rails (e.g. such as guide rails 46, 48, as illustrated in
Although the present invention is disclosed and illustrated in connection with the disc brake assemblies illustrated, it will be appreciated by those skilled in the art that the present invention is applicable with other brake assemblies, and such is contemplated by the disclosure and claims set forth herein.
In accordance with a preferred embodiment, assemblies 10 include a caliper bracket, generally indicated at 45, which is secured to a fixed, non-rotatable component of the vehicle (not shown).
As illustrated in the embodiments of
As illustrated, each caliper bracket 45 slidably supports, on a first side thereof, the first end 17A of the first backing plate 17 and the first end 18A of the second backing plate 18, and, on a second side thereof, the second end 17B of the first backing plate 17 and the second end 18B of the second backing plate 18. In this way, the first end of the first backing plate is slidable along the first guide rail and the second end of the first backing plate is slidable along the second guide rail, and the first end of the second backing plate is slidable along the first guide rail and the second end of the second backing plate is slidable along the second guide rail. In an alternative embodiment, with the caliper bracket 45 including the aforementioned first slot and second slot, the first end of the first backing plate is slidable within the first slot and the second end of the first backing plate is slidable within the second slot, and the first end of the second backing plate is slidable within the first slot and the second end of the second backing plate is slidable within the second slot. In all such embodiments, the guide rails or slots provide for sliding movement of the subassemblies 17, 18.
To effect braking action of the wheel, caliper 40 and piston(s) 35 are provided for urging the braking subassemblies 17, 18, and friction pads 25 in particular, towards each other so as to frictionally engage the opposing sides of rotor 15. The particulars of a caliper and related assembly for the present invention is well known to those skilled in the art, and need not be elaborated on herein for purposes of brevity. To be sure however, the caliper and related assembly illustrated and disclosed in, for example, U.S. Pat. No. 5,549,181 can be used with the present invention and so the disclosure thereof is incorporated by reference herein in its entirety. That is, and as also would be understood by those skilled in the art, when it is desired to actuate the disc brake assembly 10 to stop the rotation of rotor 15 and the vehicle wheel associated therewith, the driver of the vehicle depresses the brake pedal (not shown), and as known in the art, the depression of the brake pedal causes pressurized hydraulic fluid to urge piston(s) 35 into engagement with braking subassembly 17. As a result and in the embodiments provided, friction pad 25 associated with braking subassembly 17 is moved into frictional engagement with the associated surface of rotor 15. At the same time, the caliper 40 slides in the opposite direction as would be understood in the art to urge friction pad 25 associated with braking subassembly 18 into frictional engagement with the associated outer surface of rotor 15. As a result, the rotor 15 is frictionally engaged by the friction pads 25 to inhibit relative rotational movement thereof.
Now, in accordance with preferred embodiments of the present invention, pad spreaders, generally indicated at 70A in
Preferably, the pad spreaders 70 used on each side of the caliper assembly are identical, and are preferably formed of stainless steel, music wire, harddrawn wire or galvanized harddrawn wire, although other materials can be used.
As illustrated in the various figures, the preferred pad spreaders 70 are formed of a central loop section, generally indicated at 75, and a pair of extending arms, each respectively indicated generally as 80, 85, which extend outwardly from loop section 75. As illustrated, in the preferred embodiments, arms 80, 85 are identical to each another. Some of the embodiments, such as pad spreaders 70A, 70C, 70D, 70F, 70G, may be seen to have respective “hands” generally indicated at 90, 95. Alternatively, such as in
As illustrated in the embodiments of
Importantly, it should be noted that the profile and shape of arms 80, 85 for example, are generally provided to match and/or follow the outer curvature of the caliper bracket 45, and loop 75 is generally shaped to be able to clip onto the caliper bracket as illustrated in
When installed as shown in the figures, each pad spreader 70 engages both the inner brake subassembly 17 and the outer brake assembly 18 to urge them apart from one another. For example, in the preferred embodiments, the ends of the arms of each spreader 70 (or “hands” as the case may be) preferably engage the ends 17A, 18A (e.g. the corners thereof) or 17B, 18B of the backing plates 20, as illustrated in the various figures. As illustrated, the first arm of the first pad spreader is in pressing engagement against the first end of the first backing plate and the second arm of the first pad spreader is in pressing engagement against the first end of the second backing plate, while the backing plates sits on the guide rails. Alternatively, in
The other pad spreader 70, which is preferably identical, engages the opposite ends of the inner and outer brake subassemblies in a mirror image-like manner.
The pad spreader as illustrated in
In addition, in certain of the preferred embodiments, such as for example and not limitation with respect to pad spreaders 70A, 70B, each has a configuration and are used in connection with an assembly 10 such that they are further secured to the respective assembly 10 by the loop sections 75 being snap fit onto the caliper bracket 45.
Preferably, the arms 80, 85 of each pad spreader 70 are slightly compressed between the inner and outer braking subassemblies 17, 18 when the disc brake assembly is not actuated, as illustrated. In this way, compression of the pad spreader 70 is maintained.
In operation, as braking subassemblies 17, 18 move inwardly toward each other, arms 80, 90 of the respective pad spreaders 70 compress. Because of the inherent resiliency of the material used to form the pad spreader 70 and the shape of loop section 75 and the arms themselves, each pad spreader 70 remains operative to exert a magnitude of force against each of the braking subassemblies 17, 18 urging them apart from one another. Each pad spreader 70 is designed to “spring back” and apply a restoring force sufficient to spread the braking subassemblies 17, 18 apart from one another when the disc brake assembly 10 is subsequently released.
Test results show that each pad spreader 70 exerts a sufficient amount of spring (i.e. biasing) force against the braking assemblies 17, 18 in order to reduce the active portion of the drag and reduce the amount of active gripping of the friction pads against the rotor.
Moreover, as known the art, as friction pads 25 wear down and become increasingly thinner with repeated usage of the disc brake assembly 10, such friction pads 25 must move closer toward one another when the brake pedal is depressed in order to frictionally engage rotor 15. However, pad spreaders 70 are effective in maintaining a sufficient magnitude of force against the backing plates 17, 18 to spread them apart after engagement with the rotor.
While the present invention has been illustrated and described in connection with a “sliding” caliper type of disc brake assembly, the invention may be used with other disc brake assemblies, as would be understood by those skilled in the art and therefore, the present invention should not be limited to only the disc brake assembly illustrated and discussed herein.
Reference is also briefly made to the figures in connection with the following for a discussion of referred mounting methods of the various embodiments of pad spreaders 70 onto various configurations of conventional braking assemblies. For example, and with reference to
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While the invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the scope and spirit of the invention.
It can thus be see that an improved friction pad spreading device that overcomes the perceived deficiencies in the prior art is provided. In particular, the improved friction pad spreading device as set forth herein effectively operates over the life of the friction pads, thereby providing sufficient compression and restoring forces regardless of the wear upon the friction pad. Based thereon, it can also be see that the present invention provides for increased gas mileage and prolonged life of the braking pad because of the reduction in drag and friction of the friction pads against the rotor, just to name but a few advantageous results.