Brake Assembly

Field of the Invention:

The subject matter described herein, in general, relates to a brake assembly and in particular relates to an improved structure for a brake drum for use in such a vehicle drum brake assembly.

Background of the Invention:

Most vehicles are equipped with a brake system for slowing or stopping movement of the vehicle in a controlled manner. A typical brake system includes either a disc brake assembly or a drum brake assembly for each of the wheels. The brake assemblies are typically actuated by hydraulic or pneumatic pressure generated by an operator of the vehicle depressing a foot pedal, pulling a hand lever, and the like. Operation of brake assemblies as well as the actuators therefore is well known in the art.

A drum brake includes a brake panel, brake shoe, spring brake shoe, cam brake and lever cam brake. The brake panel has brake shoes operably attached thereto. The brake shoes are disposed to produce friction force in cooperation with the brake drum. The brake shoe is moved outwardly apart from one another into frictional engagement with the cylindrical braking surface of the brake drum. When the lever brake cam is actuated it in turn rotates the cam brake actuating mechanism to move brake shows apart from one another.

Typically, the inner surface of the brake panel has ribbed design formed along the full surface of the brake panel. The said rib design has been found to influence the wear pattern of the drum. Since these ribs are formed throughout the inner surface of the brake panel, it increases the overall weight of the drum brake and as well utilises more material.
Therefore the present invention tries to provide a unique rib pattern which takes the wear of the brake drum and the weight of the brake drum.

Summary of the Invention:

An object of the present invention is to provide a rib pattern on the brake panel such that the brake drum becomes light weight and increases the life of brake drum.

Another object of the present invention is to avoid water entry into the brake drum.

Yet another object of the present invention is to provide a cost effective brake panel for brake drum.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. Brief Description of the Invention:

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein

Figure 1 shows a conventional motorcycle.

Figure 2 shows the exploded view of the brake assembly according to the present invention.

Detail Description of the Invention:

The present invention now will be described more fully hereinafter with different embodiments. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather those embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the invention to those skilled in the art.

With reference to figure 1 a motorcycle comprises of a frame (101), front fork (102) attached to a pivot tube (201) of the vehicle frame, a front wheel (103) attached to these front forks (102), a handle bar (104) connected to the front forks (102), a fuel tank (105) attached so as to straddle an upper part of the vehicle frame, a seat (106) attached to the upper rear portion of the vehicle frame, an engine unit (107) attached to the lower front section of the vehicle frame, a swing arm (108) attached to a lower rear section of the vehicle frame, suspended by a rear shock absorber (not shown) from the vehicle frame and a rear wheel attached to a rear end of swing arm (108). The intake system of the engine comprises of a fuel air metering device such as a carburetor (109), intake duct and an air cleaner. The exhaust system of the engine comprises of exhaust pipe and a muffler.

The motorcycle is also provided with a side cover for covering a side section of the vehicle frame, a seat cover for covering a rear section of the vehicle frame below the seat, a front fender (110) for covering an upper part of the front wheel (103), and a rear fender (111) for covering an upper part of the rear wheel (112). The drive from the engine (107) is transmitted from the engine to the driven wheel sprocket mounted on the rear wheel hub mounted on the rear wheel assembly.

According to the present invention and referring to figure 2, the drum brake 202 includes a brake panel 203. The said brake panel 203 supports brake shoes by means of supporting member. A lever brake cam 204 is provided to actuate the a cam brake mechanism 205 by rotating the cam which in turn moves brake shoes outwardly in a direction apart from each other. The said brake panel inner surface 203a is provided with atleast one elliptical rib 203b around the axis of rotation. The two ends of the elliptical rib 203b which is near to the walls of the brake panel is provide with star shaped ribs 203c. In other words the cam bore and pivot pin area is supported by the star shaped ribs 203c. The directions of the said ribs 203c are aligned in the direction of transmitting torque. Cam bore boss and pivot pin boss on brake panel is strengthened by providing star shaped ribs 203c around it.

Ribs are provided to the said two boss areas with preferably 45 degree between the centreline of adjacent ribs with respect to bore axis. The said ribs 203c joins the panel base wall and boss outside diameter in the form of a fillet. The said ribs 203c thickness and width is optimized to obtain stiffer design. Mass property of casting panel is reduced enormously.

A groove 203d on the outer circumference is provided to avoid water and dust ingress.

The lever brake cam 204 according to the present invention is made in a thin plate wherein it is provided with a hexagonal opening 204a to accommodate the cam lever locking area. The said cam lever locking area is provided with a similar hexagonal profile to match with the said hexagonal opening in the lever brake cam. The said hexagonal locking arrangement allows to adjust the said lever brake cam at definite angles.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We claim:

1. A drum brake assembly comprises:

a brake panel having cam bore boss and pivot pin boss;

a brake shoe housed within the brake panel; and

a cam brake actuating mechanism to rotate the cam in order to move the brake shoe apart from each other;

wherein the said brake panel inner surface is provided with atleast one elliptical rib around the axis of rotation and the said elliptical ribs gradually merges with star shaped ribs provided at cam bore boss and pivot pin boss areas; and

wherein the said brake panel outer circumference is provided with a groove.

2. The drum brake assembly as claimed in claim 1, wherein the said star shaped ribs are provided to support the cam bore and pivot pin areas.

3. The drum brake assembly as claimed in claim 1, wherein the said brake panel is preferably made up of aluminium cast.

4. The drum brake assembly as claimed in claim 1, wherein the said brake panel is preferably made up of sheet metal

5. A drum brake assembly as substantially shown and described in the specification.