JPS6113430Y2 - - Google Patents

Description

[Detailed explanation of the invention] Industrial application field This invention temporarily stores the power of shifting operation performed when the bicycle is stopped, and releases this stored power at the same time as the bicycle starts. The present invention relates to an exterior transmission for an automobile configured so that a chain can be changed to a desired gear position.

Conventional Techniques and Problems The external transmission for automobiles generally has a fixed frame, an inner link, an outer link, and a movable frame connected to each other with parallelogram pins to form a pantograph link mechanism, and one end of the fixed frame is attached to a bicycle. In addition to being fixed to the frame, a chain guide member is attached to the movable frame, and the parallelogram-shaped pantograph link mechanism and an operating lever etc. attached to an appropriate part of the bicycle frame are connected via a double wire consisting of an inner wire and an outer wire. so that the relative movement between the inner wire and the outer wire caused by the rotating operation of the operating lever is transmitted to the pantograph link mechanism, thereby deforming the pantograph link mechanism to perform a desired chain replacement operation. It's summery. The pantograph link mechanism is always biased by a spring to deform in a predetermined direction, and when the inner wire of the double wire is pulled, the pantograph link mechanism deforms against the spring, and vice versa. When the inner wire is loosened, the pantograph link mechanism returns to its original state due to the elasticity of the spring.

However, with an external transmission having only the above configuration, there is a problem that a gear change operation cannot be performed when the bicycle is stopped, that is, when the chain suspended between the crank gear and the multi-stage freewheel is not in a running state. . This type of external transmission is constructed in such a way that, before the running chain engages with the freewheel, the chain is swung from side to side along the tips of the freewheel's teeth, and the chain is sequentially transferred to the desired transmission gear. This is because Even if an attempt is made to shift the transmission while the bicycle is stopped, the pantograph link mechanism is in a fixed state, so the operating wire will only become tense, and the operating lever cannot actually be rotated. If you try to forcefully rotate the lever at this time, there is a risk that the inner wire will stretch or the wire attachment part will be damaged.

By solving these problems, it is possible to rotate the control lever even when the chain is not in a running state, and moreover, as soon as the bicycle starts, the chain automatically adjusts the amount of rotation of the control lever. A variety of external transmissions have been proposed so far, in which the transmission can be changed to a desired transmission gear.

A typical example of such an improved external transmission is a rear derailleur disclosed in Japanese Patent Publication No. 11742/1983. However, in this rear derailleur, it is necessary to make the elasticity of one of the two springs interposed in the pantograph link mechanism greater than the elasticity of the other, which increases the bulk of the spring and makes the transmission itself large. In addition, there is the problem that the elasticity of one of the springs is extremely large, making it difficult to assemble. Furthermore, if the elasticity of the two springs is incorrectly set,
There is also the problem that a predetermined function cannot be performed.

Further, US Pat. No. 3,903,751 discloses a pantograph formed by swingably supporting the bases of a pair of link members with respect to a fixed housing and pivoting a movable member at the tips of the pair of link members. In an external bicycle transmission equipped with a link mechanism, an actuation arm that extends toward the outside of the pantograph link mechanism and is swung by an operating cable is pivotally supported by a pin that pivotally supports the housing and the link member. , in which the pin is fitted with both a first torsion spring that biases the actuation arm against the housing and a second torsion spring that biases the actuation arm against the link member. .

However, in this configuration, since the operating arm extends toward the outside of the pantograph link mechanism, the appearance of the transmission becomes uncoordinated, and the protruding operating arm may cause injury to the passenger. Furthermore, since both the first torsion spring and the second torsion spring are inserted into the same pin on which the actuating arm is pivoted, the coil portion of the torsion spring has a larger diameter than necessary, making it difficult to use in practice. There is a problem in that it is difficult to secure space for inserting the torsion spring into the sleeve. Furthermore, since the two torsion springs are inserted into the sleeve in a double manner, there is a risk that one spring may rub against the other spring, affecting its operation, and causing the transmission to malfunction. In addition, the torsion angle of the first spring and the second spring accompanying the rotation of the actuation arm is large, the rotation angle of the actuation arm is small and large, or the amount of deformation of the pantograph link mechanism is small. There is also a problem in that there is a large difference in the elasticity stored in the spring when the spring is large, and therefore both springs need to have a larger initial stored force than necessary.

This invention solves the problems of each of the above conventional examples at once, and adds innovation to the method of interposing two springs.
By using the elasticity of these two springs more efficiently,
To provide an exterior transmission for a bicycle, which can temporarily store gear shift operating force when the chain is stopped, and release the accumulated operating force when the chain starts running to change the chain to a desired sprocket. purpose.

Means for solving the problem In order to achieve this purpose, the present invention:
The following technical measures have been taken:

That is, a pantograph link mechanism consisting of a fixed frame, an inner link and an outer link whose proximal ends are swingably connected to the fixed frame, and a movable frame swingably connected to the tips of these inner links and outer links; A bicycle external transmission comprising a chain guide member attached to the movable frame, and configured such that the chain guide member is moved in parallel when the pantograph link mechanism is deformed, wherein either an inner link or an outer link is provided. an actuating arm that can substantially abut against the inner surface of the pantograph link mechanism and extends toward the interior of the pantograph linkage; A second torsion spring is inserted into a pin pivotally supporting the actuating arm and is provided to bias the actuating arm in a direction away from the fixed frame or the movable frame. and a first torsion spring for biasing the actuating arm toward the inner surface of the inner link or the outer link in relation to the inner link or the outer link, the second torsion spring being connected by a pin in which the second torsion spring is inserted. The actuating arm attaches one end of the operating wire which is provided by inserting it into the pin on the opposite side of the inner link or the outer link and which is pulled by the operating means, in response to the pulling operation. said first
It is linked to this actuating arm so as to rotate in a direction that opposes the biasing force of the torsion spring or the second torsion spring.

Operation and Effect By interposing the first torsion spring and the second torsion spring as described above, the second torsion spring is
While only the torsion spring deforms and performs the gear shifting action,
When the bicycle is stopped (so-called locking), operating the operating wire deforms both the first torsion spring and the second torsion spring, and when the bicycle starts running from this state (so-called saver), the storage of the first torsion spring is deformed. The force automatically switches the chain to the desired transmission gear. In the external transmission according to the present invention,
The point behind the above-mentioned Japanese Patent Publication No. 53-11742 is that the stored force of the first torsion spring is released only during so-called lock and save times, and does not perform any action during normal gear shifting, thereby making efficient use of the spring force. This is significantly different from the rear derailleur described in . This known rear derailleur is configured so that both springs deform even during normal gear shifting, so in order to deform the pantograph link mechanism in one direction during normal gear shifts, one spring is more deformed than the other. It was necessary to increase its elasticity, which caused the various problems mentioned above.

Further, in the present invention, the actuating arm, which is pivotally connected to the pin connecting the fixed frame or the movable frame and the inner and outer links, is disposed so as to extend inside the pantograph link mechanism, and the actuating arm is arranged so as to extend inside the pantograph link mechanism. a second torsion spring for biasing the arm in the direction of separation in relation to the fixed frame or the movable frame; and a first torsion spring for biasing the actuating arm toward the inner and outer links in relation to the inner and outer links; , the problem with the transmission described in the above-mentioned US Pat. No. 3,903,751 is also solved by inserting the pins into separate pins located at both ends of the inner and outer links.

In other words, because the operating arm is arranged so as to face the inside of the pantograph link mechanism, the operating arm does not protrude to the outside, which could cause a part of the rider's body to come into contact with it and cause injury. Never. In addition, by inserting the first torsion spring and the second torsion spring that bias the actuating arm into separate pins, there is no need to make the coil part of each torsion spring larger than necessary, which saves space. This is advantageous, and the torsion springs do not interfere with each other in terms of function. Furthermore, since the movable frame pivotally supported by one of the pins at both ends of the inner link member or the outer link member is biased by the first torsion spring inserted into the other pin, the first torsion spring The length of the end that is latched to the operating arm of the first torsion spring is increased, so that the amount of torsional deformation of this first torsion spring due to the swinging of the operating arm or the deformation of the pantograph link mechanism is reduced. . Therefore, the difference in the elastic force of the first torsion spring when the amount of swing of the actuating arm is small and large is reduced, thereby making it possible to reduce the initial elasticity of the first torsion spring to the necessary minimum. This means that the force needed to rotate the actuating arm during so-called saver mode is small.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

The drawing shows an embodiment of an external bicycle transmission according to the present invention. This embodiment includes an inner link 2 and an outer link 3 whose proximal ends are swingably connected to a fixed frame 1, and a movable frame 4 which is swingably connected to the tips of these inner links and outer links.
A bicycle exterior comprising a pantograph link mechanism 5 consisting of a pantograph link mechanism 5 and a chain guide member 7 attached to the movable frame 4, and configured such that the chain guide member is moved in parallel when the pantograph link mechanism 5 is deformed. In the transmission, an actuating arm 8 that can substantially abut against the inner surface of the inner link 2 and extends toward the inside of the pantograph link mechanism 5 is connected to the inner link 2 and the movable frame 4.
A second torsion spring 10 is pivotally attached to a pin 12a connecting the actuating arm 8 with the movable frame 4, and a second torsion spring 10 is attached to the movable frame 4 to urge the actuating arm 8 in a direction away from the movable frame 4. A first torsion spring 9 is inserted into the supporting pin and is provided to bias the operating arm 8 toward the inner surface of the inner link 2 in relation to the inner link 2. Connecting pin 12
The first torsion spring 9 is provided by being inserted into the actuating arm 8 and biases one end of the operating wire 6 pulled by the operating means in response to the pulling operation. Alternatively, an example is shown in which the actuating arm 8 is linked to rotate in a direction opposing the biasing force of the second torsion spring 10.

The fixed frame 1 is attached to the rear end plate of the bicycle via a bracket 11, and includes the fixed frame 1, an inner link 2 and an outer link 3 extending in parallel from the fixed frame, and a frame located at the tips of these links 2 and 3. The movable frame 4 is connected to each other by pins 12a, 12b, 12c, 12.
d to form a parallelogram-shaped pantograph link mechanism 5. A chain guide member 7 including a guide pulley and a tension pulley 13 is attached to the movable frame 4, and when the pantograph link mechanism is deformed, the chain guide member 7 together with the movable frame 4 moves to the tooth tip of a multi-stage freewheel (not shown). is translated along.

The operating wire 6, whose one end is fixed to an operating lever (not shown) attached to an appropriate part of the bicycle frame, is composed of a double wire consisting of an inner wire 17 and an outer wire 15.
The other end of the outer wire 15 is attached to an inner wire fixing portion 18 provided on the outside of the movable frame 4, and the other end of the outer wire 15 is attached to an outer receiver 16 provided at the tip of the operating arm 8. The operating arm 8 is bent in a substantially dogleg shape and is located below the pantograph link mechanism 5, and its base end 19 is pivotally connected to a pin 12a that connects the movable frame 4 and the inner link 2. Therefore, when the operating wire 6 is operated to cause relative movement between the inner wire 17 and the outer wire 15, the operating arm 8 swings about the pin 12a.

An engaging pin 20 is provided at an appropriate midpoint of the operating arm 8 to project upward, and when this pin 20 comes into contact with the inner surface of the inner link 2, one end of the swinging range of the operating arm 8 is fixed. stipulated. Note that this engagement pin is also an engagement portion with which one ends of a first torsion spring 9 and a second torsion spring 10, which will be described later, engage.

The first torsion spring 9 and the second torsion spring 1
0 is installed as follows.

The first torsion spring 9 has its coil portion 24 inserted into a pin 12b that connects the fixed frame 1 and the inner link 2 with each other, and its one end 21 engaged with a protrusion 22 provided on the inner link 2. The other end 23 is engaged with an engagement pin 20 protruding from the operating arm 8 from the inside.

The second torsion spring 10 has its coil portion 25 inserted into the pin 12a that connects the inner link 2 and the movable frame 4 with each other, and its one end 26 is engaged with a suitable position of the movable frame 4 (the side wall in this embodiment). and the other end 27 is engaged with the engagement pin 20 protruding from the operating arm 8 from the inside.

Next, the operation of the above embodiment will be explained based on FIGS. 4 to 7 (these are bottom views).

First, the operation when the bicycle is in a state in which it is possible to travel will be explained.

FIG. 4 shows a state in which the inner wire 17 is loosened, and at this time the movable frame 4 is located at the top P. This is due to the action of the second torsion spring 10 which tends to separate the operating arm 8 and movable frame 4 from each other, and because the operating arm 8 is substantially in contact with the inner surface of the inner link 2. As a result, this second torsion spring 10
acts to separate the inner link 2 and the movable frame 4 via the operating arm 8. On the other hand, the first torsion spring 9 acts to press the operating arm 8 against the inner link 2, but since this is an effect only on the relationship between the operating arm 8 and the inner link 2, it acts to deform the pantograph link mechanism 5. Don't talk. When the inner wire 17 is pulled here, the outer wire 15 moves forward and the actuating arm 8 tries to rotate in the direction of arrow R, but since no external force is acting on the movable frame 4 to fix it, the actuating arm 8 moves forward. While the arm 8 and the inner link 2 maintain their elastic contact state due to the action of the first torsion spring 9, the angle between the operating arm 8 and the movable frame 4 decreases, and the movable frame 4 moves toward the low side (in the direction of the arrow Q). , the state shown in FIG. 5 is reached. That is, at this time, only the second torsion spring 10 is deformed and elasticity is stored, and the first torsion spring 9 does not perform any action. Therefore, the inner wire 17 may be pulled with a force that overcomes the elasticity of the second torsion spring 10. Next, the inner wire 17 is in the pulled state, that is, the fifth movable frame 4 is on the low side.
When the pulling force of the inner wire 17 is relaxed from the state shown in the figure, the stored force of the second torsion spring 10 is released, and the actuating arm 8 and the movable frame 4 tend to separate from each other. As described above, since the operating arm 8 and the inner link 2 are brought into elastic contact with each other by the first torsion spring 9, the stored force of the second torsion spring 10 causes the inner link 2 and the movable frame 4 to move toward each other. The pantograph link mechanism 5
The movable frame 4 is deformed to move toward the top side (in the direction of arrow T) and returns to the state shown in FIG.

Next, a description will be given of the operation when the bicycle is in a stopped state, that is, a locked state in which the movable frame 4 is fixed by the stopped chain, and the locked state is released and the movable frame 4 enters the saver state in which it is movable.

When the inner wire 17 is pulled in the state shown in FIG. 4, the pantograph link mechanism 5 cannot be deformed, so as the outer wire 15 moves forward, only the actuating arm 8 rotates in the direction of arrow R, as shown in FIG. The state shown is shown. At this time, both the first torsion spring 9 and the second torsion spring 10 are deformed. Next, when the bicycle starts and the movable frame 4 is unlocked, the stored force of the first torsion spring 9 is released, and the pantograph link mechanism 5 is transformed from the state shown in FIG. 6 to the state shown in FIG. , the movable frame 4 automatically moves from the top side (in the direction of arrow P) to the low side (in the direction of arrow Q). At this time, the second torsion spring 10 has no effect on the return deformation of the pantograph link mechanism 5 because the angle between the operating arm 8 and the movable frame 4 remains regulated by the amount of pulling of the operating wire 6. Don't do it.

On the other hand, when the inner wire 17 is loosened when the movable frame 4 is locked in the state shown in FIG. 5, the inner wire 17 is loosened as shown in FIG. 7 because the deformation of the pantograph link mechanism 5 is prevented. state. After that, when the movable frame 4 is unlocked, the second torsion spring 1
The pantograph link mechanism 5, in which the stored force of 0 is released, transforms from the state shown in FIG. 7 to the state shown in FIG. 4, and the movable frame 4 moves from the low side (direction of arrow Q) to the top side (direction of arrow P). automatically move to.
At this time, the first torsion spring 9 is not deformed in any way with the operating arm 8 and the inner link 2 in elastic contact with each other, and has no effect on the deformation of the pantograph link mechanism 5 described above.

The present invention is based on the same principle as the above embodiment,
The following embodiments can be adopted.

(1) Connect the operating arm 8 to the outer link 3 and the movable frame 4
A first torsion spring is pivotally connected to a pin 12d connecting the two members, and urges the actuating arm 8 to come into elastic contact with each other in relation to the outer link 3. a second biasing element for biasing the
The torsion spring 10 is attached to the pins 1 at both ends of the outer link 3.
Insert the mantle into 2c and 12d, respectively.

(2) Connect the operating arm 8 to the inner link 2 and the fixed frame 1.
A primary torsion spring is pivotally connected to a pin 12b connecting the inner link 2 to the inner link 2, and a key torsion spring is used to urge the actuating arm 8 to come into elastic contact with each other in relation to the inner link 2. the second for urging in the direction of separation;
Connect the torsion spring to the pins 12 at both ends of the inner link 2.
Insert the sleeves into a and 12b, respectively.

(3) Connect the operating arm 8 to the outer link 3 and the fixed frame 1.
A first torsion spring is pivotally connected to a pin 12c connecting the first torsion spring and the first torsion spring is pivotally connected to a pin 12c connecting the first torsion spring to the first torsion spring for biasing the operating arm 8 so as to come into elastic contact with each other in relation to the outer link 3; The second torsion springs 10 are connected to pins 1 at both ends of the outer link 3 for urging them apart from each other.
Insert the mantle into 2d and 12c, respectively.

As mentioned above, in all the embodiments described above, the operating wire 6 should be attached so that the degree of mutual separation between the operating arm 8 and the fixed frame 1 or the operating arm 8 and the movable frame 4 can be changed. This will be clear from the explanation of the effect.

In the bicycle external transmission according to the present invention, as a result of adding innovation to the method of interposing the first torsion spring 9 and the second torsion spring 10 as described above, the first torsion spring 9 or the second torsion spring 10 is Pantograph link mechanism 5 with one of the stored forces released
When the spring deforms, it acts independently without being affected by the elasticity of the other spring, so there is no need to differentiate the elasticity of the two springs, as seen in the rear derailleur described in Japanese Patent Publication No. 53-11742. For example, the first torsion spring 9 and the second torsion spring 10 can be set to be elastic at the same time. Furthermore,
Since the first torsion spring 9 and the second torsion spring 10 only need to have enough elasticity to overcome the low resistance required for replacing the chain, the spring stiffness can be set extremely small, making design and manufacturing easy. At the same time, the number of failures during use can be drastically reduced.

Further, in the present invention, the pantograph link mechanism is substantially deformed, and the actuating arm 8 is arranged to extend inside the pantograph link mechanism for accumulating operating force when the pantograph is locked. Therefore, there is no possibility that a part of the rider's body will come into contact with this operating arm and cause injury. Also,
Since the first torsion spring 9 and the second torsion spring 10 are separately inserted into the pins at both ends of the inner link 2 or the outer link 3, two coils of torsion springs can be arranged without difficulty. Furthermore, since the amount of torsion of the first torsion spring 9 during the saver mode is reduced, the initial elasticity of the first torsion spring 9 can be set to be relatively small, thereby reducing the wire pulling resistance during the saver mode. Become.

Furthermore, according to the present invention, an exterior transmission having a so-called saver function can be constructed by simply incorporating the operating arm 8 and two types of torsion springs into a conventional general exterior transmission, thereby simplifying its structure. It also has the effect that it can be manufactured at low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a front view thereof, and FIG. 2 being a perspective view of the main parts viewed diagonally from above.
FIG. 3 is a bottom view of the main parts, and FIGS. 4 to 7 are schematic bottom views showing the operation of the present invention. 1...Fixed frame, 2...Inner link, 3...
Outer link, 4... Movable frame, 5... Pantograph link mechanism, 6... Operating wire, 7... Chain guide member, 8... Operating arm, 9... First torsion spring, 10... Second torsion spring .

Claims (1)

[Claims for Utility Model Registration] From a fixed frame, an inner link and an outer link whose base ends are swingably connected to the fixed frame, and a movable frame which is swingably connected to the tips of these inner links and outer links. An external bicycle transmission comprising: a pantograph link mechanism; and a chain guide member attached to the movable frame, and configured such that when the pantograph link mechanism is deformed, the chain guide member is moved in parallel. For connecting an operating arm that can substantially abut the inner surface of either the link or the outer link and extends toward the inside of the pantograph link mechanism, with its base end connecting the inner and outer links of the fixed frame or the movable frame. a second torsion spring pivotally attached to the pin of the actuating arm and biasing the actuating arm in a direction away from the fixed frame or the movable frame; a first torsion spring that is inserted into the pin and is provided to bias the actuating arm toward the inner surface of the actuating arm in relation to the inner link or the outer link; the second torsion spring is inserted into the pin; The operating wire is provided by inserting it into a pin on the opposite side of the pin of the inner link or outer link connected by the operating means, and furthermore, one end of the operating wire is pulled by the operating means. The arm urges the first
1. An external bicycle transmission, characterized in that the external transmission is connected to the operating arm so as to rotate in a direction opposing the biasing force of a torsion spring or a second torsion spring.