JPH0439105Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention mainly relates to a cantilever brake that is attached to a front fork or a back fork of a bicycle frame.

(Prior Art) Generally, this type of brake has a brake shoe and a wire locking part on a pair of fixed bases fixed to the fork, as described in Japanese Utility Model Publication No. 1828/1983. A pair of cantilever levers are pivotally supported such that the locking portion is on the opposite side of the wheel rim, and each of the levers is attached between each of these cantilever levers and the fixed base in a direction away from the wheel rim. At the same time, each cantilever is brought close to the wheel rim by interposing a return spring that urges the wheel rim, and both ends of a center wire are locked in each of the locking portions, and a pulling operation of an operating wire attached to the center portion of the center wire is performed. It is configured to perform braking by swinging in the direction.

(Problem to be Solved by the Invention) However, in a bicycle equipped with a wheel in which a large number of treads are provided discontinuously in the circumferential direction, if the operating wire attached to the center wire breaks unexpectedly, the cantilever The restoring force of the return spring causes the center wire to rotate in a direction away from the wheel rim, and the center wire, which is installed between the wire locking portions of the cantilever, moves downward and bites between the treads of the wheel, so that the center wire It will be pulled forward in the forward rotation direction of the wheel. Then, due to the tensile action of the center wire, the cantilever rotates in a direction approaching the wheel rim against the force of the return spring, and the brake shoe is pressed against the wheel rim, causing sudden braking. Ta.

The present invention was devised in view of the above-mentioned conventional problems, and its purpose is to prevent sudden braking from occurring in the event that the operating wire attached to the center wire breaks unexpectedly.

(Means for Solving the Problems) Therefore, the present invention provides the brake shoes 21, 2
1 and a pair of cantilever levers 2, 2 having wire locking portions 22, 22, return springs 4, 4 for each of these levers 2, 2, and the locking portions 22, 22 at both ends.
22, the cantilever brake is equipped with a center wire 5 having locking bodies 51, 51, which lock at least one of the locking parts 22, 22, and a locking piece facing the rotational direction of the wheel. 22a,2
2b, and the locking piece 22
Among the locking pieces a and 22b, the locking piece located on the front side in the forward rotation direction of the wheel can be displaced toward the front by pulling the center wire 5 forward, and the locking piece of the locking body It is designed to release the lock from the part.

(Function) If the operating wire attached to the center wire 5 is accidentally cut, the cantilever levers 2, 2 will rotate in the direction away from the wheel rim due to the restoring force of the return springs 4, 4, and the cantilever levers 2, 2 will rotate in the direction away from the wheel rim. The center wire 5, which has both ends locked in the wire locking portion, is pulled diagonally downward and outward, and is pressed against the outer peripheral surface of the wheel. Due to this pressing, the center wire 5 ,
The center portion in the length direction is inserted between the treads of the wheel and is pulled forward in the normal rotational direction of the wheel. Then, due to the tensile action of the center wire, an excessive force acts on the movable locking piece 22a of the wire locking portion of the cantilever.
The movable side locking piece 22a is displaced forward in the forward rotational direction of the wheel, and the locking member 51 of the center wire 5 is moved forward.
will be released from the locking portion 22. Therefore, it is possible to prevent sudden braking from occurring.

(Embodiment) The illustrated cantilever brake has brake shoes 21, 21, a wire locking part 22, 2
A pair of cantilever levers 2, 2 having 2 and 2 are rotatably supported, and the cantilevers 2, 2 are tightened by tightening the clamping bodies 3, 3 which are screwed into the threaded holes of the cylindrical shaft.
2, and between the fixed bases 1, 1 and the cantilever levers 2, 2,
In addition to interposing coil-shaped return springs 4, 4 that bias the wheel 2 in a direction away from the wheel rim R,
the wire locking portion 22 of the cantilevers 2, 2;
22, the hanging bodies 51, 51 of the center wire 5 having hanging bodies 51, 51 at both ends are locked, and the cantilever is pulled by pulling the operating wire W attached to the central part of the center wire 5. By rotating the levers 2, 2 in the direction of arrow X in FIG. 1 against the return springs 4, 4 and releasing the braking operation,
The cantilever levers 2, 2 are rotated in the direction of arrow Y in FIG. 1 by the restoring force of the return springs 4, 4.

In the embodiment shown in FIGS. 1 and 2, the locking portions 22, 22 are formed in a hawk shape with locking pieces 22a, 22b facing each other in the rotational direction of the wheel. Of 22a and 22b, the locking piece 22a located at the front in the forward rotational direction of the wheel can be displaced forward by pulling the center wire 5 forward under braking, and the locking piece 5
1 and 51 are released from the locking portions 22 and 22.

The locking parts 22, 22 have semicircular inner surfaces with open lower surfaces, and the locking bodies 51, 51
The locking piece 22
A guide groove 22c for the center wire 5 is formed between a and 22b, and the center wire 5 is drawn out from the guide groove 22c.

In addition, the locking piece 22b is formed of a bendable metal plate such as an iron plate, in addition to the cantilever levers 2, 2 formed of a light metal such as aluminum, and has a mounting portion provided on one end thereof that can be attached to a caulking pin or the like. It is fixed to the cantilever levers 2, 2 by means of fixing means.

By pulling the center wire 5 forward, the locking piece 22a is deformed as shown by the chain line in FIG. By tapping the locking piece 22a in the direction of the locking piece 22b, the deformation of the locking piece 22a is returned to its original shape, and the locking piece 51, 51 is placed opposite the locking piece 22b. This allows the lock to be locked again.

Therefore, the operating wire W attached to the center wire 5 is unexpectedly cut, and the cantilevers 2, 2 are moved to the wheel rim R due to the restoring force of the return springs 4, 4.
The center wire 5 is rotated in a direction away from the center wire 5, and both ends of the center wire 5 are pulled outward and diagonally downward and pressed against the outer peripheral surface of the wheel, and the center wire 5 bites between the treads T of the wheel S. , the wire locking portion 22 in the cantilevers 2, 2 is pulled forward in the forward rotation direction of the wheel.
By displacing the locking pieces 22a, 22a of 22 as described above, the wire locking portions 22, 22 of the locking bodies 51, 51,
22 can be released from the lower open side of the locking portions 22, 22, so sudden braking can be prevented.

In addition, the locking pieces 22a, 2 of the locking portions 22, 22
The means for displacing the center wire 2a is formed separately from the cantilever levers 2, 2 as shown in FIG. The locking piece 2 is pulled forward in the forward rotation direction of the wheel.
2a, 22a may be displaced about the vertical axes 23, 23 in the direction of the arrow in FIG. In this case, in order to prevent the locking pieces 22a, 22a from being accidentally displaced in the opening direction, the locking bodies 51,
It is preferable to provide flanges 51a, 51a at both ends of 51. In addition, when the flanges 51a, 51a are provided, when the locking pieces 22a, 22a are displaced by the tension of the center wire 5, the flanges 51a, 51a are distorted, and the locking members 51, 51 Since it becomes difficult to separate from the locking pieces 22a, 22a, the inner surfaces of the flanges 51a, 51a should be made into tapered surfaces as shown in FIGS. 5
1 and 51, and may be attached so as to be detachable by fitting, and detached by pulling the center wire 5 in the forward direction.

Further, in the embodiment described above, the wire locking portions 22, 22 of the cantilever levers 2, 2 are formed in a shape having two locking pieces 22a, 22a and 22b, 22b, so that each cantilever 2, Although the two locking pieces 22a, 22a are made movable, the wire locking portion 22 of only one of the movable levers 2, 2 is made movable.
is formed into a shape having two locking pieces 22a and 22b, one of the locking pieces 22a is movable,
The locking body 51 on one side may be detached from the wire locking portion 22 by pulling the center wire 5 forward.

(Effect of the invention) As described above, the present invention has the advantage that the brake shoes 21, 2
1 and a pair of cantilever levers 2, 2 having wire locking portions 22, 22, return springs 4, 4 for each of these levers 2, 2, and the locking portions 22, 22 at both ends.
At least one of the locking parts 22, 22 in a cantilever brake equipped with a center wire 5 having locking bodies 51, 51 that lock on the locking pieces 22a, 2 facing in the rotational direction of the wheel.
2b, and the locking piece 22
Of a and 22b, the locking piece located on the front side in the forward rotation direction of the wheel can be displaced toward the front by pulling the center wire 5 forward, and the locking piece of the locking body Therefore, the operation wire attached to the center wire 5 may be accidentally cut, and the center wire 5 may get stuck between the treads of the wheel and be pulled forward in the forward rotation direction of the wheel. Even if this occurs, the tensioning of the center wire 5 can release the locking of the locking body 51 from the wire locking portion 22, thereby preventing sudden braking.

Furthermore, the wire locking part of the cantilever is formed into a fork shape with opposing locking pieces, and one of the locking pieces is movable, making it extremely simple to make sudden braking possible. It can be provided at a low cost while preventing people from working.

[Brief explanation of the drawing]

Figure 1 is a front view showing one embodiment of the brake of the present invention, Figure 2 is a perspective view of only the main parts, Figure 3 is a perspective view of only the main parts showing another embodiment, and Figures 4 to 6. The figure is an explanatory diagram showing yet another embodiment. 2, 2... Cantilever lever, 4, 4... Return spring, 21, 21... Brake shoe, 5...
Center wire, 22, 22... wire locking part,
22a, 22b...Locking pieces.

Claims (1)

[Scope of utility model registration request] Brake shoes 21, 21 and wire locking part 2
A pair of cantilever levers 2, 2 with 2, 22
and the return springs 4, 4 of these levers 2, 2.
and a center wire 5 having locking bodies 51, 51 at both ends that are locked to the locking parts 22, 22, the cantilever brake having at least one of the locking parts 22, 22, It is formed into a fork shape with locking pieces 22a, 22b facing in the rotational direction of the wheel, and among the locking pieces 22a, 22b,
A locking piece located on the front side in the forward rotational direction of the wheel can be displaced toward the front by pulling the center wire 5 forward, and the locking body can be locked to the locking portion. A cantilever brake that is characterized by its ability to be released as if it were released.