JPH0353991Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This idea consists of a pair of left and right brake arms that are swingably supported in the middle while being elastically biased in the direction in which the lower brake shoes are constantly expanded, and arranged between the upper ends of each brake arm. This invention relates to an improvement in a bicycle caliper brake configured to swing and perform braking by moving a cam up and down.

[Prior art and its problems]

Among the caliper brakes, there is a cam-driven caliper brake, which is designed to reduce the distance from the brake shoe to the swinging fulcrum in the brake arm as much as possible to obtain a large braking force. The structure of a conventional brake of this type will be explained with reference to drawings showing embodiments of the present application. A pair of left and right brake arms 4, 5 are swingably supported on support shafts 2, 3 provided on the backhawk or front fork 1 at intermediate portions thereof. Brake shoes 8 and 9 facing the rim 7 of the wheel 6 are attached to each of the lower ends of each brake arm 4 and 5, and grooved roller-shaped cam followers 10 and 11 are rotatable at each upper end. Supported by Further, each brake arm 4, 5 is always connected to the brake shoe 8,
9 are biased by separate springs 12 in the direction away from the wheel rim 7, ie in the brake release direction. In the example shown in the figure, each brake arm 4, 5
are biased as described above by a coiled torsion spring housed in the boss portion at the intermediate portion thereof. On the other hand, a plate-shaped cam 14 having a substantially triangular shape in front view that simultaneously engages with the outer circumferential groove of each cam follower 10, 11 at the upper end of each brake arm 4, 5 is attached to the spring 12.
The cam followers 10 and 11 are held between the cam followers 10 and 11, which tend to elastically approach each other due to the urging force of the brake cable 13, and are pulled upwardly by the brake cable 13. The brake cable 13 is connected to, for example, a brake lever attached to a handle (not shown), and is pulled upward in the figure when the brake lever is operated in the braking direction. When the brake lever is operated in the braking direction as described above, the cam 14 is pulled upward in the figure by the cable 13. Since the distance between the cam surfaces 14a and 14b formed on both side edges of the cam 14 increases downward, the two cam followers 10 and 11 move at this time so that the distance between them is expanded. That is, each arm 4,
5 is forced to swing in the direction of arrow B in the figure. As a result, the brake shoes 8 and 9 at the lower end of each brake arm 4 and 5 press the rim of the wheel to perform braking. Conversely, when the operating force on the brake lever in the braking direction is relaxed, the cam followers 10 and 11 of both brake arms 4 and 5 tend to elastically approach each other, causing the cam 14 to move downward. That is, at this time, the brake arms 4 and 5 are
It swings back in the direction of arrow A due to its elasticity. Each brake shoe 8, 9 separates from the rim of the wheel and the brake is released.

[Problem that the invention attempts to solve]

By the way, the cam 14 is simply sandwiched between the cam followers 10 and 11, which tend to approach each other due to the elasticity of the spring 12 that urges each brake arm 4 and 5, and its vertical movement trajectory is restricted to a constant level. It's not that it's being done. Therefore, if an imbalance occurs in the biasing force that should be applied to the spring 12 that biases the left and right brake arms 4 and 5, the cam 14 will shift in the left-right direction and the entire brake will not be symmetrical, resulting in what is called a one-sided condition. The problem of effectiveness arises. For example, if the initial stored force applied to the spring that should bias the brake arm 5 on the right side of the figure is weaker than the initial stored force applied to the spring that should bias the brake arm 4 on the left side of the figure, The cam 14 is displaced to the right from the position shown in the figure, and when this becomes noticeable, a state occurs in which the brake shoe 8 of the right brake arm 5 is constantly in contact with the rim 8. In other words, the right brake arm 5 is defeated by the biasing force of the left brake arm 4 and is swung in the braking direction via the cam 14. In the conventional brake structure of this type, the only way to avoid the above problem is to adjust the biasing forces to be applied to the left and right brake arms 4, 5 to be equal when not braking. Such adjustment work is very troublesome and time consuming, and as a result, conventional brakes of this type have very poor assembly workability. This idea was devised under the above circumstances, and it solves the conventional problems and dramatically improves the workability of assembling this type of cam-driven bicycle caliper brake. That is the issue.

[Means to solve the problem]

In order to solve the above problem, this invention takes the following technical measures. That is, in the bicycle caliper brake of this invention, the intermediate portion is swingably supported with respect to the bicycle body at the left and right positions sandwiching the bicycle tire.
A pair of left and right brake arms are provided with a cam follower at the upper end and a brake shoe at the lower end, and the brake shoe is always elastically biased in the direction away from the tire. and a cam that can be moved to expand or shorten the distance between the tips of both brake arms, and the cam comes into contact with one of the brake arms and causes the swinging end of the brake arm in the direction of elastic biasing. A defining stopper is provided integrally with the bicycle body, and the biasing force applied to the brake arm whose swing end is defined by the stopper is set to be larger than the biasing force applied to the other brake arm. It is said that

[Effect]

In the present invention, the biasing force applied to the brake arm (hereinafter referred to as the first brake arm) whose swing end in the resilient biasing direction (brake release direction) is regulated by the stopper is applied to the other brake arm ( This is made larger than the biasing force applied to the second brake arm (hereinafter referred to as the second brake arm). Therefore,
When the brake is not applied, the first brake arm tries to overcome the biasing force of the second brake arm and swing in the direction of releasing the brake, but the first brake arm comes into contact with the stopper and remains stationary at a fixed position. I am made to do so. That is, the cam follower at the upper end of the first brake arm is placed at a fixed stationary position, and therefore, in this state, the second brake arm is not affected by the biasing force of the first brake arm. There is no. As a result, when not braking, the first brake arm,
The second brake arm and the cam sandwiched between these cam followers always take a constant posture, and the conventional one-sided effect is completely avoided. When the cam moves upward during braking, the second brake arm, which has a weak biasing force, first swings in the braking direction. Then, when the brake shoe of the second brake arm comes into contact with the wheel and the rocking resistance in the braking direction increases, and this becomes equal to the biasing force of the first brake arm, the cam moves the first brake arm in the braking direction. Shake it. After the brake shoe of the first brake arm also comes into contact with the wheel, the brake shoes of both brake arms pinch the wheel from both sides to perform braking. Conversely, when the brake is released, the first brake arm, which has a large biasing force in the brake release direction, first swings in the brake release direction to the swing end regulated by the stopper, and then the second brake arm swings in the brake release direction, and both brake shoes return to the above-mentioned non-braking state in which they are separated from the wheels.

【effect】

As described above, the bicycle caliper brake of the present invention solves the problems of conventional brakes of this type by simply adding a stopper that restricts the swinging end of the first brake arm on the brake release side. The problem of one-sided effects can be easily avoided. In other words, it is very difficult to equalize the biasing force of separate springs, but it is extremely easy to adjust the biasing force of one spring to be greater than the biasing force of the other spring. This is because it can be done.

[Explanation of Examples]

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Incidentally, the explanation of the matters already mentioned in the explanation of the prior art will be omitted here. As shown in detail in FIG. 3, each leg 1a of the front fork or back hawk, which is located across the wheel, has a large diameter base part 2a and a small diameter shaft part 2b at the tip.
and an axial screw hole 2c (these parts of the support shaft 3 are not shown in the figure) are fixed at the base ends of the large diameter portions by welding or the like. On the other hand, boss portions 15 and 16 are formed in intermediate portions of each of the brake arms 4 and 5 to be supported by the support shafts 2 and 3, respectively. Each boss portion 15, 16 is formed with a bottomed large diameter portion 17 in which the tip side of the support shaft 2, 3 is open, into which the coiled torsion spring 12 is to be loaded, and the bottom of this bottomed large diameter portion 17 is A bush 18 to be rotatably fitted onto the small-diameter shaft portion 2b at the tip of each of the support shafts is inserted so as to penetrate the wall. The spring 12 is
The one end of the locking portion 12a is hooked into the locking hole 19 provided at the bottom of the bottomed large diameter portion, and the end is inserted into the annular space surrounded by the bottomed large diameter portion 17 and the support shaft 2. loaded. The other end locking portion 12b of the spring 12 is fitted into a locking hole 22 on the inner surface of a spring receiver 21 that is pressed against the distal end surface of the support shaft 2 by a screw 20 that is screwed into the screw hole 2c of the support shaft 2. be engaged. The distance from the end surface of the large diameter portion 2a of the support shaft 2 to the inner surface of the spring receiver 21 is slightly larger than the axial length of the boss portions 15, 16 of the brake arms 4, 5, and therefore, The above screw 20
Even if the brake arms 4 and 5 are screwed,
can swing around the support shafts 2 and 3. As shown in FIG. 1, the outer surface of the spring receiver 21 is formed with a parallel tool engaging surface 23 on which a rotating tool such as a spanner can be hung. When applying an initial biasing force to each brake arm 4, 5 or adjusting the biasing force, loosen the screw 20,
is turned by the desired amount with a tool, and the screw 20 is tightened. At this time, the coiled torsion spring 1
2 is twisted and charged. When the screw 20 is tightened, the spring receiver 21 becomes integral with the support shafts 2 and 3, so one end 12b is locked thereto, and the other end 12a of the spring 12, which has been given a stored force, is locked therein. The brake arms 4 and 5 are given a biasing force to elastically rotate one side about the support shafts 2 and 3. Of course, the biasing direction in this case is the brake release direction in which the brake shoes 8 and 9 tend to move away from the wheels, as shown by arrow A in the figure. In the present invention, the brake arm on the side whose swing end on the brake release side is regulated by a stopper 24 to be described later;
That is, the biasing force to be applied to the first brake arm 4 is made larger than the biasing force to be applied to the other brake arm, that is, the second brake arm 5. The stopper 24 includes a ring portion 24a that is fitted onto the large diameter portion 2a of the support shaft 2, and an arm portion 24b that extends from the ring portion 24a to the outer surface of the portion of the first brake arm 4 below the boss portion 15. Equipped with Ring part 2
4a is fixed by abutting a set screw 25 screwed thereon in the radial direction against the outer surface of the large diameter portion 2a. Further, an adjustment bolt 26 that can be adjusted forward and backward toward the outer surface of the brake arm 4 is screwed into the tip of the arm portion 24b.
That is, the tip of the adjustment bolt 26 comes into contact with the outer surface of the first brake arm 4 to regulate the swing end. By adjusting the adjustment bolt 26 forward or backward, the swing end of the first brake arm 4 when braking is not applied can be finely adjusted. In the above configuration, in the non-braking state shown by the solid line in FIG. The brake arm 4 is positioned at the swing end in the brake release direction by the stopper 24. Therefore, the brake arm 5 is not affected by the biasing force of the brake arm 4 as in the conventional case, and as a result, the cam followers 10 and 11 of each brake arm 4 and 5 and the cam 14 interposed between them are It can be stopped at a fixed position in the left and right direction. By adjusting the amount of threading of the adjustment bolt 26 so that the postures of the brake arms 4 and 5 are symmetrical, there will be no possibility of a one-sided situation where one brake shoe contacts the wheel when not braking. It disappears. When a brake lever (not shown) is operated in the braking direction to move the cam 13 upward, the second brake arm 5 with the smaller initial biasing force is first moved in the braking direction (arrow B
direction). During this process, the spring that biases the second brake arm 5 gradually accumulates additional energy, or the brake shoe 9 comes into contact with the wheel, so that the swinging resistance of the left and right brake arms 4 and 5 becomes equal. Become. At this point, the first brake arm 4, which has a larger initial biasing force, is also swung in the direction of arrow B, and the left and right brake shoes 8 and 9 pinch the wheel from both sides to perform a braking action (see Fig. 1). virtual line). There is a difference in the movement of the left and right brake arms 4, 5, but in the end both brake arms 4,
Since the driving force in the braking direction is transmitted to the motor 5 via the brake cable 13 or the cam 14,
There are no problems with braking ability. Conversely, when the braking force on the brake lever is released, the first brake arm 4
first swings back in the direction of arrow A, and then the second brake arm 5 swings back in the direction of arrow A. Then, the left and right brake arms 4, 5 return to their non-braking positions shown by solid lines in FIG. Of course, the scope of this invention is not limited to the embodiments described above. Each brake arm 4,
The type of spring for biasing 5 does not matter. In short, any spring can be used as long as it can bias the pair of brake arms 4 and 5 separately. The biasing force to be applied to this spring may be adjustable as shown in the example shown, or springs with clearly different spring coefficients may be used as springs when the left and right brake arms are biased. You can. The mode of the stopper 24 is also not limited. Adjustment bolt 25 is not essential. In addition, in the illustrated example, a stopper is applied to the outer surface of the portion of the brake arm below the boss portion 15 to restrict the swinging end, but the stopper is applied to the inner surface of the portion of the brake arm above the boss portion. No matter how you do it, the action and effectiveness are exactly the same.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a side view, and FIG. 3 is a sectional view taken along the line - in FIG. 4, 5... Brake arm, 8, 9... Brake shoe, 10, 11... Cam follower, 14...
...Cam, 24...stoppa.

Claims (1)

[Scope of Claim for Utility Model Registration] The intermediate portion is swingably supported with respect to the bicycle body at the left and right positions sandwiching the bicycle tire, and a cam follower is provided at the upper end and a brake shoe is provided at the lower end, and, A pair of left and right brake arms whose brake shoes are constantly elastically biased in a direction away from the tire and each cam follower are simultaneously engaged and moved up and down, allowing the distance between the tips of both brake arms to be expanded or contracted. In a bicycle caliper brake comprising a cam, a stopper is integrally provided on the bicycle body, and a stopper that comes into contact with one of the brake arms to define a swinging end of the brake arm in an elastic biasing direction is provided, and the stopper is provided integrally with the bicycle body. A caliper brake for a bicycle, characterized in that a biasing force applied to a brake arm whose swing end is defined by is set larger than a biasing force applied to the other brake arm.