Patent Application
20050161291
1. Field of the Invention
The present invention relates to a disk brake, and more particularly to a disk brake for a bicycle and having a low friction to make the operation of the disk brake smooth.
2. Description of Related Art
With reference to
The biasing member mounted between the driven member (63) and the locking piece (66) to provide a restitution force to the driven member (63). The locking piece (66) is secured in the body (50) to hold the biasing member in place. The locking piece (66) has a central hole (not number) defined to allow the driven member (63) to extend through the central hole. The locking nut is secured in the body. The brake pads (68) are mounted in the body (50) and face each other. The brake pads (30) are respectively held in place by the driven member (63) and the locking nut.
When the user pulls the handle bar, the lever (52) will be actuated to pivot relative to the body (50) to rotate the driving member (62) with the lever (52). The driven member (63) will be pushed to move relative to the body (50), and the brake pads (68) will be pushed to squeeze a disk mounted on a wheel of a bicycle. Accordingly, a braking effect is provided.
However, because the gasket (72) contacts with each ball of the ball bearing (70) at a single point, the pressure between the gasket (72) and the balls of the ball bearing (70) is huge. The surface of the gasket (72) is easily scraped, and slight scrapes are formed on the surface of the gasket (72). Consequently, the surface roughness of the gasket (72) is increased, such that the friction between the gasket (72) and the ball bearing (70) is also increased to make the operation of the disk device not smooth.
To overcome the shortcomings, the present invention tends to provide a disk brake to mitigate or obviate the aforementioned problems.
The main objective of the invention is to provide a disk brake for a bicycle and having a low friction to make the operation of the disk brake smooth. The disk brake has a body, a lever and a driving device. The lever is pivotally mounted on the body. The driving device is mounted in the body and has a driving member, a driven member, two brake pads, a ball bearing and two washers. The driving member is rotatably mounted in the body and is connected to and actuated by the lever. The driven member is reciprocally received in the body and is connected to and actuated by the driving member. The brake pads are mounted in the body, and one of the brake pads is connected to the driven member. The ball bearing with multiple balls is mounted in the body and around the driving member. The washers are mounted around the driving member and place the ball bearing between the washers. Each washer has a contact side facing to each other and an annular groove with a concave bottom defined in the contact side to receive the balls of the ball bearing in cooperation with the groove in the other washer. Accordingly, the contact area between the balls and the washers will be enlarged, and the surfaces of the washers are not easily scraped or damaged.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
With reference to
The driving member (21) is rotatably mounted in the body (10) and is connected to and actuated by the lever (12). The driven member (22) is reciprocally received in the body (10) and is connected to and actuated by the driving member (21). To connect the driven member (22) to the driving member (21), multiple guiding recesses are respectively defined in the driving member (21) and the driven member (22). Multiple steel ball (23) are respectively mounted in the pairs of facing guiding recess in the driving member (21) and the driven member (22).
The brake pads (26) are mounted in the body (10), and one of the brake pads (26) is connected to the driven member (22) to move with the driven member (22). To connect the brake pad (26) to the driven member (22), a magnet (not shown) is secured in one end of the driven member (22) to attract the brake pad (26) onto the driven member (22). In addition, a biasing member (not numbered) is mounted around the driven member (22) to provide a restitution force to the driven member (22).
The ball bearing (30) with multiple balls is mounted in the body (10) and around the driving member (21). In an optional embodiment, the balls of the bearing (30) are rotatably mounted on an annular ball holder (32). The washers (34) are mounted around the driving member (21) and place the ball bearing (30) between the washers (34). Each washer (34) has a contact side facing to each other and an annular groove (342) with a concave bottom defined in the contact side to receive the balls of the ball bearing (30) in cooperation with the groove (342) in the other washer (34).
With the arrangement of the grooves (342) with concave bottoms in the washers (34), the contact area between the balls and the washers (34) are enlarged. Accordingly, the pressure between the balls and the washers (34) is reduced, so that the surface of the washers (34) will not be scraped or damaged and can be kept at an excellent smoothness. This can make the operation of the disk brake smooth and at a low friction.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
