JPH077634Y2 - Bicycle brake shoes - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to improvement of a friction surface of a brake shoe in a bicycle rim brake device.

[Prior art]

Conventionally, various configurations have been proposed as a brake shoe in a bicycle rim brake device in which a brake shoe is pressed against a wheel rim of a bicycle from both sides thereof for braking. In particular, in order to ensure the braking even in rainy weather, the bicycle brake shoe 30 of Japanese Utility Model Publication No. 51-53561 shown in FIG. The holding pieces 23 are provided on both longitudinal edges of the surface of the holding piece 21, and the holding pieces 23
A contact surface 28 with a rim of a bicycle wheel in a rubber body 25 made of hard rubber or the like sandwiched between 23 is formed in a columnar, substantially V-shaped projection 28 ', and the apex angle of the generally U-shaped character is formed. A configuration is disclosed in which the portion 29 is mounted so as to be located forward with respect to the rotation direction of the wheels. According to this, since the friction surface is wider and the friction coefficient is larger than that of the rectangular uneven shape, braking is increased. Also, when the road surface is wet, such as in the case of rain, the water droplets adhering to the rim surface are discharged to the outside on both sides along the substantially V-shaped shape at the forefront, so the water droplets are removed and contact with the rim. It is possible to prevent slips on the surface and obtain suitable results. However, in the bicycle brake shoe, since the contact surface with the rim is set parallel to the rim, the above function cannot be efficiently performed. That is, in the conventional bicycle rim brake device, as shown in FIG. 9, the contact surface 28 of the brake shoe in which the mounting bolt 22 is fitted in the brake arm 24 and fixed by the nut 26.
Are arranged in such a way that they are pressed in the direction C and are parallel to the surface 27 of the wheel rim, said contact surface 28 being at the same time surface 27 of the rim.
Works to abut. As a result, the brake shoe 30 rotates in the direction of arrow A about the point P supporting the brake shoe 30. As a result, the brake shoe contact surface 28 and the rim 27 during braking are
It is known that the contact pressure on the friction surface of the rim significantly increases on the entry side of the rim than on the exit side of the rim. That is, in this case, the entry side of the brake shoe into the rim is rotationally displaced toward the rim surface 27 side about the fulcrum P which is a connection point with the operating piece (brake arm) of the brake device.
A uniform contact surface 28 of the brake shoe along the surface 27 of the rim
It was found that the brake shoe was not able to be pressed against, and the function of the V-shaped brake shoe was not utilized efficiently. Therefore, a structure in which the surface along the rim of the brake shoe is an inclined surface, and the front end side is most separated from the rim is actually used.
Although proposed in No. 11351, since the point supporting the brake shoe is at the center position, it has a drawback that a large force is applied to braking and the connecting portion is easily twisted and damaged.

[Problems to be solved by the device]

This invention was devised as a result of earnest research in view of the above circumstances, and its main problem is to make the contact surface of the brake shoe, which is a substantially V-shaped protrusion, uniformly contact the rim surface during braking. In order to provide a brake shoe for a bicycle, the braking force is increased to further improve the braking force in rainy weather.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides (a). The contact surface with the wheel rim, which is the surface of the block body, is formed into a plurality of substantially V-shaped projections, and the apex angle portions of the V-shaped projections are formed in front of the wheel rotation direction. The brake shoes for a bicycle arranged in parallel so that (b). Set the point that supports the brake shoe to the center position (C). The thickness of the contact surface in the front-rear direction with the wheel rim is set thin so that the front end of the contact surface with respect to the normal rotation direction of the wheel is separated from the wheel rim, (d). The thickness from the end portion to a substantially central position in the longitudinal direction of the brake shoe is set in an inclined shape in which the thickness gradually increases so as to gradually approach the rim, (e). A technical measure is taken to set the thickness from the substantially central position of the contact surface to the rear end portion to the same thickness so as to be parallel to the rim.

[Action]

This brake shoe is attached so that the apex angle portion of the V-shape formed on the contact surface in the front-rear direction with the rim is positioned forward with respect to the rotation direction of the wheel, and the contact surface in the front-rear direction of the front half is It has a thin tapered surface so that it separates from the rim, and the front and rear contact surfaces of the latter half are set to the same thickness so that they are parallel to the rim. When pressed, a force that rotates in the direction of arrow A is applied to the brake shoe around the point P that supports the brake shoe, and the tapered surface of the first half portion is gradually deformed while pressing the latter half portion, becoming parallel to the rim surface, The surface pressure on the friction surface between the brake shoe and the rim during braking becomes substantially uniform, and the rim can be pressed by contacting all the surfaces of the brake shoe. Then, in that state, in rainy weather, the water droplets attached to the rim surface are drained to both outer sides along the shape by the frontmost substantially V-shaped contact surface, and the water droplets are discharged to the rearward substantially V-shaped contact surface. Since there is no risk of stagnation, it is possible to prevent slippage and perform braking extremely efficiently and reliably.

【Example】

A preferred embodiment of a bicycle brake shoe according to the present invention will be described below with reference to the drawings. 1 to 3 show a shoe body 1 made of hard rubber for a bicycle brake shoe. The shoe body 1 is provided on an operating piece (brake arm) 4 of a caliper brake and other bicycle braking devices for bicycles. The holder 5 is used by being fitted (see FIG. 7). The shoe body 1 has a plurality of (three in the illustrated example) protrusions 8A, 8B, 8C, which are surface portions and contact surfaces 8 with a bicycle wheel rim, which are arranged in a vertical plane and are substantially V-shaped. It is formed with planar incomplete substantially V-shaped auxiliary protrusions 8D, 8E partially formed at both front and rear ends. Further, the apex angle portions 9A, 9B, 9C of the substantially V-shaped projections 8A, 8B, 8C and the apex angle portion 9E of the rear end auxiliary projection 8E are forward with respect to the rotation direction B of the wheel. Are arranged as follows. Further, the contact surface 8 further extends from the front end portion to the substantially central position with respect to the rotation direction of the wheel from the auxiliary protrusion 8D and the protrusion 8A.
The surface connecting the top surface of the protrusion 8B with a part of the protrusion 8B is formed to be a tapered surface 2 that gradually inclines at a predetermined gradient in the thickness direction of the shoe main body 1 and rises. The optimum value of this gradient is experimentally determined based on the shape and material of the shoe body 1. Next, a part of the projection 8B from the center position of the contact surface 8 of the shoe body 1 to the rear end, the projection 8C and the auxiliary projection 8E.
Is formed so that the surface connecting the top surfaces of the two is substantially horizontal. Therefore, when the shoe body 1 is fitted into the holder 5 and the mounting screw 5A protruding from the holder 5 is fitted into the mounting hole of the operating piece (brake arm) 4 of the brake device and fixed with the nut 6, the rim surface 7 is formed. On the other hand, the contact surface 8 where the tapered surface 2 is formed is arranged so as to gradually approach the surface 7 side of the rim with respect to the rotation direction B of the wheel. Then, the contact surface 8 at the part which forms the horizontal surface 3 following the contact surface 8
Are arranged parallel to each other and relatively close to the surface 7 of the rim. With such a configuration, during braking, as shown in FIG. 7, a force is applied from the operating piece 4 in the rim approaching direction C,
The left and right break shoes move in parallel as shown by the solid line. When the horizontal surface 3 comes into contact with the surface 7 of the rim and is further pressed in the direction C, the point at which the operating piece 4 and the holding tool 5 are connected and which supports the brake shoe 30 during braking is an arrow on the brake shoe. A force that rotates in the direction of A is applied. Then, the tapered surface 2 gradually approaches so as to be parallel to the surface 7 of the rim, and the surface pressures on the friction surfaces of the brake shoe and the rim become substantially uniform, so that all contact surfaces 8 of the shoe body 1 have a uniform surface pressure. The surface 7 can be clamped. Then, in that state, in rainy weather, water droplets adhering to the rim surface 7 are sequentially drained to both outsides along the shape by the auxiliary protrusions and the protrusions at the front end, and the water droplets may stay on the rear contact surface. Since it does not occur, it is possible to prevent slippage and perform braking extremely efficiently and reliably. 4 to 7 show different embodiments of the present invention. The shoe body 1 of this brake shoe has notches 8D ′, 8 at the upper and lower corners of each end of the frontmost contact surface 8 and the rearmost contact surface.
By E ', the tip and rearmost contact surfaces are also formed in a V shape as much as possible to enhance the function of removing water droplets and further improve the efficiency. In addition, a step 8F is formed on both side edges in the longitudinal direction to serve as a drainage guide, and the appearance is further improved. Since the other structures are the same as those of the above-mentioned embodiment, the same structures are designated by the same reference numerals and the description thereof will be omitted. Further, in the above embodiment, the auxiliary protrusions are provided in the front and rear of the shoe body to increase the contact area with the rim surface as much as possible, but in this invention, the front and rear auxiliary protrusions may be formed. Needless to say, the number of substantially V-shaped protrusions is not limited to that in this embodiment.

[Effect of device]

In this invention configured as described above, during braking,
First, the rear half of the surface of the V-shaped projection of the brake shoe presses against the rim, and then the front half of the surface bends and presses against the rim, so that the entire surface of the shoe is used as the contact surface and evenly strikes the rim. Therefore, it is possible to make uniform the surface pressure on the friction surfaces of the brake shoe and the rim during braking, and it is possible to significantly improve the braking efficiency. In addition, since the substantially V-shaped contact surface formed on the brake shoe is in uniform pressure contact with the rim surface, the water droplets adhering to the rim surface sometimes get wet due to the frontmost substantially V-shaped contact surface in rainy weather. The water is drained to both outsides along the shape, and there is no risk of water droplets stagnating on the substantially U-shaped contact surface behind it, so slipping can be prevented and braking can be performed extremely efficiently and reliably. Further, since the contact surface uniformly presses the surface of the rim, it is possible to prevent lateral displacement of the rim and generation of resonance noise during braking.

[Brief description of drawings]

1 is a plan view of a shoe body of a preferred embodiment of the present invention, FIG. 2 is a central longitudinal sectional view of FIG. 1, FIG. 3 is a side view of the same, and FIG. FIG. 5 is a plan view of a shoe body of a different embodiment, FIG. 5 is a sectional view taken along line VV of FIG. 4, FIG. 6 is a sectional view taken along line VI-VI of FIG. 4, and FIG. FIG. 8 is a perspective view showing a conventional brake shoe, and FIG. 9 is a view for explaining the relationship between the brake shoe and the rim during braking. 1 …… Shoe body 2 …… Tapered surface 3 …… Horizontal surface 8 …… Contact surface 7 …… Rim 9 …… Vertical corner

Claims (1)

[Scope of utility model registration request] 1. A contact surface with a wheel rim, which is a surface of a block body, is formed with a plurality of substantially V-shaped projections, and the apex angle portion of the V-shaped projections rotates a wheel. In a bicycle brake shoe that is arranged parallel to the front of the wheel, the point that supports the brake shoe is set to the center position, and the contact surface in the front-rear direction with the wheel rim is forward with respect to the forward rotation direction of the wheel. The thickness of the end of the brake shoe is set thin so as to be separated from the wheel rim, and the thickness from the end to the approximate center position in the longitudinal direction of the brake shoe is set to be gradually thicker so as to gradually approach the rim. The thickness from the approximate center of the contact surface to the rear end,
A brake shoe for a bicycle, characterized in that it has the same thickness so as to be parallel to the rim.