JPH0439103Y2 - - 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. 51-25893. A pair of cantilever levers are pivotally supported so that the locking portions are 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.

When replacing the wheel, generally, the tension on the operating wire is loosened by operating a quick release mechanism provided in the brake lever device, and the cantilever is moved from the non-braking position to the non-braking position using the restoring force of the return spring. By rotating the cantilever in a direction away from the rim, the distance between the brake shoes on this cantilever is widened, and the wheel can be removed from between these brake shoes.

(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.

Furthermore, when replacing the wheels, if the tension on the operating wires is loosened, the distance between the brake shoes on each cantilever becomes wider than the width of the wheels;
On the other hand, since the distance between the wire locking portions becomes narrower than the width of the wheel, the cantilever is rotated against the restoring force of the return spring so that the distance between the wire locking portions becomes wider than the width of the wheel. There was a problem that it was difficult to replace the wheels because the wheels had to be replaced in such a condition.

The present invention was devised in view of the above-mentioned conventional problems, and the purpose is to prevent sudden braking from occurring in the event that the operating wire attached to the center wire breaks unexpectedly, and also to prevent wheel replacement. The point is to make it easy to do.

(Means for Solving the Problems) Therefore, the present invention provides a pair of cantilever levers 2, 2 having a brake shoe and a wire locking portion.
A cantilever brake comprising fixed bases 1, 1 for pivotally supporting the cantilever levers 2, 2, return springs 4, 4 and a center wire 5 suspended between the locking portions, the cantilever brake One of the levers 2, 2 and the fixed bases 1, 1 is provided with a regulating portion 7, 7 for regulating the range of rotation of the cantilevers 2, 2 in the direction away from the wheel rim, and the other is provided with a regulating portion 7, 7. 7 are provided, and the engaging bodies 8, 8 are connected to the regulating portions 7, 8.
7, and in a direction that allows rotation away from the wheel rim relative to the restriction position regulated by the restriction portions 7, 7 of the cantilevers 2, 2. A means for lifting restrictions has been established.

still,. In the present invention, the fixed pedestals 1, 1 are provided with the restricting parts 7, 7 or the engaging parts 8, 8, and they are provided not only on the fixed pedestals 1, 1 themselves, but also on the members fixed to the fixed pedestals 1, 1. This also includes cases.

(Function) When the operating wire attached to the center wire 5 is accidentally cut, the regulating parts 7, 7 and the engaging bodies 8, 8 engage with each other, causing the cantilevers 2, 2 to rotate in the direction away from the wheel rim. Since the center wire 5 can be prevented from getting wedged between the treads of the wheel, when replacing the wheel, the cantilevers 2, 2 can be fixed to the fixed pedestal 1,
1, by forcibly rotating the regulating portions 7, 7 in a direction away from the wheel rim from the engagement position with the engaging bodies 8, 8, the brake shoe interval in the cantilever levers 2, 2 can be reduced. The distance between the wire locking parts can be wider than the wheel width without becoming too narrow, and the wheel can be easily replaced.

(Example) The illustrated cantilever brake has a cylindrical shaft 11 with a threaded hole in a fixing base 1, which is fixed to the front fork and back fork of a bicycle frame.
11, the boss portions 21, 21 of a pair of cantilever levers 2, 2 having cylindrical boss portions 21, 21, brake shoes 22, 22, and wire locking portions 23, 23 are rotatably supported. , the cylinder shaft 11,
While holding the cantilevers 2, 2 by tightening the clamping bodies 3, 3 which are screwed into the screw holes 11,
Coiled return springs 4, 4 are interposed between the fixed pedestals 1, 1 and the cantilever levers 2, 2, which bias each cantilever 2, 2 in a direction away from the wheel rim R, and The locking bodies 51, 51 of the center wire 5 having locking bodies 51, 51 at both ends are locked to the wire locking parts 22, 22 of the cantilever levers 2, 2, and the center wire 5 is
By pulling the operating wire W attached to the center of the cantilever levers 2, 2 are rotated in the direction of arrow X in FIG. 1 against the return springs 4, 4, and by releasing the braking operation, the cantilever levers 2, 2 are rotated in the direction of arrow Y in FIG. 4 by the restoring force of the return springs 4, 4,
Further, bottomed cylindrical members 6, 6 covering the return springs 4, 4 are supported on the cylindrical shafts 11, 11,
Rotation prevention holes 6a, 6 are provided in the bottom surfaces of the cylindrical members 6, 6.
a, and one end of the return springs 4, 4 is inserted into the rotation prevention holes 6a, 6a and the locking holes 12, 12 provided in the fixing bases 1, 1 to fix the cylindrical members 6, 6. Rotation relative to the pedestals 1, 1 is prevented.

In the embodiment shown in FIGS. 1 to 5, the cantilever levers 2, 2 are provided with first regulating portions 7, 7 for regulating the range of rotation of the cantilever levers 2, 2 in the direction away from the wheel rim R. are provided, and engaging bodies 8, 8 that can be engaged with the first regulating parts 7, 7 are provided on the cylindrical members 6, 6 fixed to the fixed pedestals 1, 1, and these engaging bodies 8, 8 are attached to the cylindrical members 6, 6 fixed to the fixed bases 1, 1. Allowing the cantilever levers 2, 2 to rotate in the direction of disengaging from their engagement with the restriction portions 7, 7, and in the direction away from the wheel rim R relative to the restriction position restricted by the first restriction portions 7, 7 of the cantilever levers 2, 2. A restriction release means is provided to enable displacement in the direction.

In the above configuration, the cantilever 2,
2 is provided with recessed portions 24, 24 on the outer surface of one end side of the boss portions 21, 21 in order to allow the cantilever levers 2, 2 to freely rotate from a non-braking position to a braking position with respect to the fixed bases 1, 1. This recessed part 2
The non-braking position side step portions 4 and 24 are used as the first restriction portions 7 and 7. Moreover, the boss portion 21,
On the outer surface of one end side of 21, there is a groove-shaped second regulating part that regulates the cantilever levers 2, 2 to a position displaced in a direction away from the wheel rim R with respect to the regulating position where the cantilever levers 2, 2 are regulated by the first regulating parts 7, 7. 9,9 is provided. Note that the second regulating portions 9, 9 are not necessarily required.

Further, the restriction releasing means includes forming the cylindrical members 6, 6 from an elastically displaceable material such as metal or synthetic resin, and providing two grooves on one side of the cylindrical members 6, 6. An elastic displacement piece 61 between these grooves,
61, and the engaging bodies 8, 8 are provided inside the tip portions of the elastic displacement pieces 61, 61.

Further, the engaging bodies 8, 8 are connected to the elastic displacement pieces 6.
1 and 61 are partially bulged and formed integrally, but they may be formed separately from the other elastic displacement pieces 61 and 61 and fixed by fixing means such as caulking or welding.

The present invention is constructed as described above. For example, during a braking operation by pulling the operating wire W, the operating wire W is unexpectedly cut, and the cantilevers 2, 2 are moved by the restoring force of the return springs 4, 4. When the cantilever levers 2, 2 are rotated in a direction away from the rim R, the first restricting parts 7, 7 provided on these cantilever levers 2, 2 engage with the engaging bodies 8, 8 on the fixed bases 1, 1 side, as shown in FIG. As a result, the rotation of the levers 2, 2 can be prevented (dotted chain line in FIG. 4), so it is possible to prevent the center wire 5 from digging into the space between the treads T of the wheel S. 5 can act on the cantilever levers 2, 2 to prevent sudden braking from occurring. still,
The center wire 5 is made of steel wire and is rigid, and its both ends are locked to the wire locking parts 23, 23 of the cantilever, so that if the operating wire W is cut, the wheel without falling down on the outer periphery of the
It stands up in the shape of a letter.

Further, when replacing the wheel by loosening the tension on the operating wire W on the brake lever device side, the tension on the operating wire W is loosened, so that the cantilever levers 2, 2 are first released from the return springs 4, 4.
The restoring force causes the first regulating portions 7, 7 to rotate in a direction away from the wheel rim R, and the first regulating portions 7, 7 engage with the engaging bodies 8, 8.

Then, when the levers 2, 2 are forcibly rotated in a direction away from the wheel rim R, the engaging bodies 8, 8 are moved to the first regulating piece 7 via the elastic displacement pieces 61, 61 constituting the regulation releasing means. , 7, and the cantilevers 2, 2
The lever 2 is displaced in a direction that allows rotation in a direction away from the wheel rim R relative to the restriction position regulated by the first restriction portions 7, 7, and is disengaged and disengaged, and as the levers 2, 2 are forcibly rotated, the lever 2 , 2 have second regulating parts 9, 9, the second regulating parts 9, 9 engage with the engaging bodies 8, 8 as shown in FIG.
The rotation of the brake shoes 22, 2 can be restricted.
2 can be made wider than the wheel width within a range where the distance between the wire locking portions 23 and 23 does not become narrower than the wheel width (as shown by the two-dot chain line in FIG. 4). Therefore, the wheels can be easily replaced without being hindered by the cantilevers 2, 2. Moreover, the lever 2,
If the levers 2 do not have the second regulating portions 9, 9, the forced rotational position of the levers 2, 2 cannot be accurately regulated;
In this case, for example, due to the contact resistance of the engaging bodies 8, 8 with the outer surfaces of the boss portions 21, 21, the levers 2, 2
The forced rotation position is maintained.

In addition, in the embodiment described above, the fixed pedestals 1, 1
Although the engaging bodies 8, 8 are provided on the cylindrical members 6, 6 which are unrotatably fixed to the
may be provided directly on the fixed pedestals 1, 1.
Further, the engaging bodies 8, 8 may be provided via elastic displacement pieces 61, 61 of a restriction release means formed integrally with the cylindrical members 6, 6 or the fixed bases 1, 1, or may be formed by a transfer body or the like. Alternatively, it may be supported via a restriction release means made of an elastic body such as a coil spring.

Further, the first regulating portions 7, 7 may be provided directly on the cantilever levers 2, 2, or may be provided on another member fixed to the cantilever levers 2, 2.

Further, in the embodiment described above, the cantilever levers 2, 2 are provided with the restriction portions 7, 7, and the cylindrical members 6, 6 fixed to the fixed base are provided with the engaging bodies 8, 8 and restriction release means. It may be provided on the contrary.

In addition to being provided on the side of the member where the engaging bodies 8, 8 are provided, the restriction releasing means may be provided on the side of the member where the regulating portions 7, 7 are provided. In this case, for example, only the portion of the boss portions 21, 21 in FIG.
1 and 21 so as to be displaceable in the radial direction, and when the levers 2 and 2 are forcibly rotated in a direction away from the wheel rim R with respect to the regulation position regulated by the first regulation parts 7 and 7, the first regulation The portion extending from the part to the second regulating part is displaced, and the first regulating part 7 of the engaging body 8,8
The cantilever levers 2, 2 can be forcibly rotated by disengaging from the cantilevers 7.

Further, although the regulating parts 7, 7 are formed in a concave shape and the engaging bodies 8, 8 are formed in a protruding shape, it is also possible to form the regulating parts 7, 7 in a protruding shape and the engaging bodies 8, 8 in a concave shape. may be formed.

(Effect of the invention) As described above, according to the invention, the center wire 5
The operating wire attached to the cantilevers 2, 2 was accidentally cut, and the restoring force of the return springs 4, 4 caused the cantilever levers 2, 2 to break.
When the cantilever rotates in a direction away from the wheel rim R, the rotation of the cantilever levers 2, 2 can be restricted by engaging the regulating parts 7, 7 and the engaging bodies 8, 8, thereby preventing sudden braking from occurring. It can be prevented.

Moreover, when replacing the wheels, the cantilever levers 2, 2 are connected to the regulating parts 7, 7 and the engaging bodies 8, 8.
the cantilever levers 2, 2 from the position where they engage.
By forcibly rotating the brake shoes 22, 22 in a direction away from the wheel rim, the distance between the brake shoes 22, 22 is reduced.
The distance between the wire locking portions 23 and 23 can be wider than the wheel width without becoming too narrow, and therefore,
This allows wheels to be replaced easily.

[Brief explanation of drawings]

Fig. 1 is a partially exploded perspective view showing an embodiment of the brake of the present invention, Fig. 2 is a sectional view of the main parts, Fig. 3 is a sectional view of the cantilever pivot, and Fig. 4 is a front view of the entire brake. FIG. 5 is a sectional view of the operating state corresponding to FIG. 2. 1, 1... fixed base, 2, 2... cantilever, 4, 4... return spring, 5... center wire, 7, 7 regulating section, 8, 8... engaging body.

Claims (1)

[Scope of utility model registration request] A pair of cantilever levers 2, 2 having a brake shoe and a wire locking portion, fixed pedestals 1, 1 that pivotally support these cantilever levers 2, 2, return springs 4, 4, and between the locking portions. A cantilever brake comprising a center wire 5 hung on the cantilever levers 2, 2 and a fixed pedestal 1,
1, a regulating part 7, 7 for regulating the rotation range of the cantilever levers 2, 2 in the direction away from the wheel rim, and an engaging body 8, which can be engaged with the regulating part 7, 7, on the other side. . A cantilever brake characterized in that a cantilever brake is provided with a restriction releasing means that can be displaced in a direction that allows rotation in a direction away from a wheel rim.