GB2288644A - Bicycle brake mechanism with an elastic,e.g. rubber,rod spring - Google Patents

Abstract

A brake mechanism includes a stationary positioning seat (20) fastened to a bicycle fork (10) and a brake caliper (30) connected operably to the stationary positioning seat (20). An elastic rod (40) is used to interconnect the two elements by insertion into passages (212, 312) and serves as a torsional spring to permit the brake caliper (30) to return to its initial position after a braking action. <IMAGE>

Description

BICYCLE BRAKE 2C}IANISM WITH A RUBBER ROD SPRING The invention relates to a brake mechanism for a bicycle, more particularly to a bicycle brake mechanism which includes a rubber rod spring for restoring of a brake shoe to its initial position after a braking action.

Referring to Figures 1 and 2, a conventional brake mechanism includes a holding post (lob), a torsional spring 2, a brake caliper 3, a locking screw 4 and a cylinder sleeve 5.

The holding post (lb) has a first end portion fixed perpendicularly to a fork blade (la) of a bicycle fork 1, a flange formed integrally adjacent to the first end portion and provided with a mounting hole (inc), and a rear end portion which is threaded internally. The cylinder sleeve 5 is sleeved rotatably on the holding post (lob). The torsional spring 2 is sleeved operably on the cylinder sleeve 5 and has a first end (2a) fixed in the mounting hole (lc) of the holding post (lob).

The brake caliper 3 includes a hollow connecting shaft (3a) which is sleeved rotatably over the cylinder sleeve 5 and permits a second end (2b) of the torsional spring 2 to engage the brake caliper 3. The locking screw 4 extends through the connecting shaft (3a) of the brake caliper 3, the cylinder sleeve 5 and engages threadedly the rear end portion of the holding post (lib).

When an external force is applied on the conventional brake mechanism, the torsional spring 2 is twisted so that the brake shoe moves to brake a bicycle wheel. Removal of the external force permits the brake shoe to retract back to its initial position due to the restoration force of the torsional spring 2.

Some of the drawbacks associated with the conventional brake mechanism are as follows: (I) In order to permit smooth rotation and to reduce friction between the brake caliper 3 and the holding post (lb), the cylinder sleeve 5 is sleeved over the holding post (lib). A clearance is formed between the connecting shaft (3a) of the brake caliper 3 and the cylinder sleeve 5. This causes vibration and noise during the braking action.

(II) Dust and water accumulate easily in the clearance. The torsional spring 2 is thus susceptible to rust and corrosion, thus shortening the useful life of the conventional brake mechanism.

(III) The cylinder sleeve 5 occasionally possesses a length which is shorter than that of the holding post (lb) so that axial vibrations may occur after the assembly thereof. This may lead to untimely ruin of the conventional brake mechanism. In the event that the length of the cylinder sleeve 5 is greater than that of the positioning post (lb), the brake caliper 3 cannot be operated after its assembly.

(IV) To avoid the above-mentioned drawback, a high precision process is required to produce the cylinder sleeve 5, which correspondingly results in additional expenses.

A main objective of the present invention is to provide a brake mechanism which has a useful life that is longer when compared to that of conventional brake mechanisms.

A second objective of the present invention is to provide a brake mechanism which is not susceptible to rusting and which vibration does not generate noise during a braking action.

Accordingly, the brake mechanism of the present invention includes a stationary positioning seat which is to be mounted on a bicycle fork and a brake caliper that is connected operably to the stationary positioning seat for braking a bicycle wheel. The positioning seat has a front end portion and a rear end portion opposite to the front end portion. A throughhole is formed through the front end portion and is transverse to a length which extends from the front to the rear end portions. A blind bore that is crossed by the through-hole is also formed at the front end portion of the positioning seat. The brake caliper includes a connecting shaft which extends into the blind bore of the positioning seat. The connecting shaft has an axis and a transverse hole that is aligned with the through-hole of the positioning seat.

An elastic rod is press-fitted into the throughhole of the positioning seat and the transverse hole of the connecting shaft of the brake caliper. The brake caliper is thus connected to the positioning seat.

In the disclosed embodiment, the elastic rod is made from a reinforced rubber material and is employed instead of a torsional spring for restoring the brake caliper to an initial position after the braking action. Since the elastic rod is not susceptible to rusting and corrosion, the useful life of the brake mechanism of the present invention is prolonged.

The positioning seat further includes a tubular projection which extends integrally and frontwardly from the front end portion thereof. The tubular projection has an internally threaded surface that confines a channel therein. The channel is communicated with the blind bore. The internally threaded surface of the tubular projection of the positioning seat is threaded with compound screw threads. The connecting shaft of the brake caliper is correspondingly threaded by compound screw threads in order to engage with the internally threaded surface of the positioning seat. The brake caliper further includes a tubular sleeve member formed integrally around the connecting shaft and which is sleeved over the tubular projection of the positioning seat after assembly.A seal ring is disposed between the tubular projection of the positioning seat and the tubular sleeve member of the brake caliper. Thus, water and dust cannot accumulate within the interior of the brake mechanism of the present invention. The compound screw threads are finer than those of conventional screw threads and serve as additional protection against dust and water.

During a braking action, the rotation of the connecting shaft of the brake caliper relative to the stationary holding seat deforms the elastic rod. When the applied force is removed, the brake caliper returns to its initial position due to the restoration force of the elastic rod.

The positioning seat can be provided with a pair of threaded holes which are communicated with the throughhole of the same. A pair of locking screws can be threaded in the threaded holes of the positioning seat so that the distal ends of the locking screws bear against the elastic rod to provide additional engagement between the elastic rod and the positioning seat. To permit ease of deformation and to facilitate restoration of the elastic rod to its initial shape, the distal ends of the locking screws can be provided with movable press units, each of which having a respective convex pressing face which bear against the elastic rod.

Other features and advantages of the present invention will become more apparent in the following detailed description of the preferred embodiment, in which: Figure 1 shows an exploded perspective view of a conventional brake mechanism mounted on a bicycle fork; Figure 2 shows a partially cross sectional view of the assembled conventional brake mechanism of Fig. 1 when mounted on the bicycle fork; Figure 3 is an exploded perspective view of a brake mechanism of the present invention; Figure 4 shows a cross sectional view of the assembled brake mechanism of Figure 3; Figure 5 shows a cross sectional view of the assembled brake mechanism of Figure 3 when viewed from another angle; and Figure 6 shows the cross sectional view of the assembled brake mechanism of Figure 5 during a braking action, illustrating the configuration of an elastic rod employed therein.

Referring to Figure 3, an exploded perspective view of a brake mechanism according to the present invention is shown. As best illustrated, the brake mechanism includes a stationary positioning seat 20 mounted securely on a bicycle fork by means of two fastening screws 61, 62, and a brake caliper 30 which is connected operably to the stationary positioning seat 20. The stationary positioning seat 20 has a front end portion 201, a rear end portion 202 opposite to the front end portion 201, and a through-hole 212 formed through the front end portion 201. The through-hole 212 is transverse to a length that extends from the front end portion 201 toward the rear end portion 202.

The stationary positioning seat 20 further has a tubular projection 22 which projects integrally and frontwardly from the front end portion 201. The tubular projection 22 of the positioning seat 20 has an internal surface 222 that confines a channel therein and extends into the front end portion 201 at a predetermined depth such that the internal surface 222 confines a blind bore 221 in the front end portion 201.

The blind bore 221 is communicated with the channel.

The internal surface 222 is formed with compound screw threads, the purpose of which will be explained in the following paragraphs. The stationary positioning seat 20 has two opposed side faces, one of which is formed with a pair of threaded holes 213 that are communicated with the through-hole 212.

The brake caliper 30 is a one-piece integrally molded unit with a brake shoe 60 mounted detachably thereon. The brake caliper 30 includes a connecting shaft 31 and a tubular sleeve member 32 which is disposed around the connecting shaft 31. The connecting shaft 31 is formed with external compound screw threads 311. The connecting shaft 31 has an axis and a transverse hole 312 adjacent to its distal end and transverse to the axis of the same. A seal ring 223 which is generally made of rubber, is sleeved over the tubular projection 22 of the stationary positioning seat 20. When the brake caliper 30 is connected to the positioning seat 20 by threading the connecting shaft 31 into the internal threaded surface 222, the compound screw threads of the latter two provide firm engagement therebetween.The seal ring 223 between the tubular sleeve member 32 of the brake caliper 30 and the tubular projection 22 of the stationary positioning seat 20 provides added protection to prevent water and dust from reaching interior of the brake mechanism.

Under such a condition, the through-hole 212 of the positioning seat 20 is aligned with the transverse hole 312 of the brake caliper 30.

An elastic rod 40 which is generally made of a reinforced rubber material is cylindrical in shape and has a diameter slightly smaller than that of the through-hole 212 of the positioning seat 20 and the transverse hole 312 of the brake caliper 30. The elastic rod 40 is press-fitted into the through-hole 212 and the transverse hole 312. Thus, the brake caliper 30 is connected operably to the stationary positioning seat 20, as shown in Figure 4. In order to obtain a firmer engagement, two locking screws 50, each of which having a distal end 512 and a press unit 52 mounted movably at the distal end 512 thereof, are threaded in the threaded holes 213 of the positioning seat 20. The press unit 52 is provided with a convex face 521 that bears rotatably against the external surface of the elastic rod 40, as shown in Figure 5.

Thus, the convex face 521 of the press unit 52 facilitates deformation and restoration of the elastic rod 40 to its initial shape during and after the braking action.

Referring to Figure 6, when an external force is applied on the brake caliper 30 in the direction shown by the arrow, the connecting shaft 31 of the former rotates relative to the stationary positioning seat 20.

The rotation of the connecting shaft 31 twists the elastic rod 40 to deform the same. When the external force is removed, the elastic rod 40 reverts its initial form by virtue of its restoration power.

Since the elastic rod 40 is press-fitted to connect the stationary positioning seat 20 and the brake caliper 30, no clearance is formed between the two elements. Therefore, no noise is generated during the braking action. The elastic rod 40 has a long useful life and is capable of withstanding rust and corrosion.

Thus, there is no need to replace the elastic rod 40 often when compared to the conventional brake mechanism.

Claims (8)

1. A brake mechanism including a stationary positioning seat which is to be mounted securely on a fork of a bicycle and a brake caliper connected operably to said stationary positioning seat for braking a wheel of said bicycle, wherein said positioning seat has front end portion, a rear end portion opposite to said front end portion, a through-hole formed through said front end portion and transverse to a length extending from said front end portion toward said rear end portion, and a blind bore formed at said front end portion along said length and crossed by said through-hole; said brake caliper including a connecting shaft inserted into said blind bore, said connecting shaft having an axis and a transverse hole formed transverse to said axis and aligned with said through-hole of said positioning seat; and an elastic rod press-fitted into said through-hole of said positioning seat and said transverse hole of said connecting shaft of said brake caliper to fasten said brake caliper to said positioning seat.

2. The brake mechanism as defined in Claim 1, wherein said elastic rod is made of a reinforced rubber material.

3. The brake mechanism as defined in Claim 1, wherein said positioning seat further includes a tubular projection extending integrally and frontwardly from said front end portion thereof, said tubular projection having an internally threaded surface which confines a channel that is communicated with said blind bore, said connecting shaft being threaded externally to engage said internally threaded surface of said positioning seat.

4. The brake mechanism as defined in Claim 3, further comprising two locking screws, said stationary positioning seat having two opposed side faces one of which being formed with two threaded holes communicated with said through-hole, said locking screws engaging threadedly said threaded holes and bearing against said elastic rod.

5. The brake mechanism as defined in Claim 4, wherein said brake caliper includes a tubular sleeve member formed around said connecting shaft and sleeved on said tubular projection, said tubular projection having a seal ring sleeved thereon so as to be disposed between an inner surface of said sleeve member and an external surface of said tubular projection.

6. The brake mechanism as defined in Claim 4, wherein each of said locking screws has a distal end and a press unit with a convex face which is mounted between said distal end and said elastic rod.

7. The brake mechanism as defined in Claim 3, wherein said internally threaded surface of said positioning seat and said externally threaded connecting shaft are formed with compound screw threads.

8. The brake mechanism substantially as described hereinbefore with reference to and as illustrated in Figures 3 to 6 of the accompanying drawings.