JPS6228550Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an external bicycle transmission, and more specifically, it has a so-called saver function that temporarily stores the shifting force applied when the bicycle is stopped and allows the chain to be changed to a desired sprocket at the same time as the bicycle is started. This invention relates to an external bicycle transmission equipped with a bicycle transmission.

Conventional external bicycle transmissions that do not have a so-called saver function have a total of four components: a fixed member fixedly attached to the rear end plate, a pair of parallel link members, and a movable member equipped with a chain guide member. A pantograph mechanism is used in which two members are linked together in a parallelogram shape using pins, and the diagonal length of this pantograph mechanism is changed using a so-called Bowden wire consisting of an outer wire and an inner wire to control the movable member. The chain guide member is moved in parallel to the fixed member to move the chain guide member near a desired sprocket, thereby changing the chain. In this case, the end of the Bowden wire on the transmission side is usually connected to the transmission body by fixing the end of the outer wire to the fixing member and the end of the inner wire to any other member other than the fixing member. By rotating an operating lever at hand, relative axial movement is applied to the outer wire and the inner wire, and the relative distance between the end of the outer wire and the end of the inner wire is changed in the transmission. It's becoming like that.

By the way, in such an external bicycle transmission, the ends of the Bowden wire are fixed to the four members themselves constituting the parallelogram pantograph mechanism, so that the parallelogram pantograph mechanism can be freely deformed. When this is not possible, i.e. when the bicycle is stationary and the drive chain suspended between the front sprocket and the freewheel is not rotating, the Bowden wire can be operated to connect the inner wire and outer wire relative to each other. Even if an attempt is made to move the operating lever, the pantograph mechanism, which is in a fixed state, locks the operating lever via the Bowden wire, and the operating lever cannot be rotated. That is, in conventional external bicycle transmissions, the deformation resistance of the pantograph mechanism is too great to perform a gear shift operation unless the bicycle is running, specifically, unless the drive chain is rotating in the forward direction.

In order to rectify this shortcoming of conventional external bicycle transmissions, we have developed a system that temporarily accumulates the shift operation force applied when the bicycle is stopped, releases this accumulated force at the same time as the bicycle starts, and automatically switches the chain to the desired sprocket. Various external bicycle transmissions have been proposed that have a so-called saver function. however,
These transmissions generally have complex structures and high manufacturing costs, and are not yet widely used.Also, there are two types of wires used in external bicycle transmissions: pull type and inner wire. No device has yet been developed that can accommodate both the push-pull type and the push-pull type.

A pull-type inner wire is made by twisting a plurality of thin wires together into a rope shape, and is highly flexible, but cannot transmit pushing force, that is, a force that compresses the wire in the axial direction. Therefore, when using this type of inner wire, a return spring is essential for the pantograph mechanism of the transmission, and when the pulling force of the inner wire is loosened, this return spring causes the pantograph mechanism to return to its original shape, causing the control lever to requires a friction member to oppose the return spring and stop the pantograph mechanism from deforming.

On the other hand, the push-pull type inner wire is
A wire made of a single wire such as piano wire, which works together with the outer wire to generate pushing force,
That is, it is possible to transmit a certain amount of force that compresses the wire in the axial direction. Therefore, when using this type of inner wire, the pantograph mechanism of the transmission does not require a return spring, and the friction member of the operating lever only needs to be able to maintain the shape of the pantograph mechanism constant, as in the case above. There is no need to counter the return spring.

This push-pull type inner wire has a smaller elastic deformation rate in the axial direction than the pull type wire.
Furthermore, since it can also transmit pushing force, the lever operation can be transmitted sharply to the transmission, and although it has the advantage of being light to operate, it has the disadvantage that once it buckles, it becomes unusable. There is.
For example, if the push-pull wire is pushed while the pantograph mechanism is in an undeformable state, the wire will definitely buckle. Therefore, a saver mechanism for avoiding this buckling is essential in a transmission using a push-pull type wire.

The saver mechanisms that have been developed so far are constructed by adding different configurations to the transmission using a push-pull type wire and the transmission using a pull type wire, so to speak. Separate developments have been made to transmissions, making it impossible to use the two types of transmissions interchangeably.

The present invention solves the above-mentioned problems and is compatible with operation wires using either pull-type inner wires or push-pull type inner wires, and is simple in structure and cost-effective for bicycles. The purpose is to provide an external transmission, in which a pantograph mechanism is formed by connecting a fixed member, an inner link, an outer link, and a movable member in a parallelogram shape, and the pantograph mechanism is deformed by an operating wire and attached to the movable member. In an external bicycle transmission configured to be able to move a chain guide member in parallel, a swinging arm is pivotally attached to an inner link or an outer link so as to be rotatable by a predetermined angle, and the swinging arm is pivoted to the inner link or the outer link. A first spring is provided for rotationally biasing the inner link or the outer link in the direction of separation, and within the rotatable angle range of the swing arm, the inner link to which the swing arm is pivotally attached is provided. The first swing arm moves a certain angle range on the side closer to the link or outer link.
The range is set to receive the biasing force of the spring, and the remaining angular range is defined as a range where the swinging arm does not receive the biasing force of the first spring, while the swinging arm separates from the fixed member when the operating wire is pulled. A spring configured to rotate and further deform and bias the pantograph mechanism in a direction opposite to the direction in which the pantograph mechanism is deformed when the operating wire is pulled,
The gist thereof is to provide a second spring whose elasticity is smaller than that of the first spring.

Hereinafter, the present invention will be specifically explained based on embodiments shown in the drawings.

1 is a fixed member attached to an appropriate bracket 2 so as to be able to swing within a certain range, to which pins 3 and 4 are attached.
One end portions of the inner link 5 and the outer link 6 are pivotally supported to face each other via. Reference numeral 7 designates a movable member which is pivotally connected via pins 8 and 9 at the tips of each of the inner link 5 and outer link 6. The members form a parallelogram pantograph mechanism A. When the inner link 5 and the outer link 6 are pivoted relative to the fixed member 1, the movable member 7 follows an arcuate trajectory while always remaining parallel to the fixed member 1 and, in turn, to the bicycle body (not shown). Moving. This arcuate trajectory is not only a trajectory on a horizontal plane as shown in the example, but also
You can tilt the bicycle forward or to the side of the bicycle.

Further, 10 is attached to the movable member 7,
A chain guide member having a chain guide ring 11 and a chain connecting ring 12 is shown.

The above configuration is the same as the basic configuration of a general external bicycle transmission, and in the present invention, the following configuration is further added to the above basic configuration, and a so-called saver mechanism is added. be.

Reference numeral 13 denotes a swinging arm that is pivotally attached to the inner link 5 or the outer link 6 so as to be rotatable by a predetermined angle, and is pivotally attached to the outer link 6 in the embodiment shown in the drawings.
This swing arm 13 has its base end connected to the fixed member 1
It is pivotally connected to the outer link 6 using a pin 4 that connects the outer link 6 and the outer link 6. Further, at the tip of the swing arm 13, an outer wire of the operation wire W is connected.
Attach W ₁ . For this purpose, a bottomed circular hole (not shown) capable of receiving the end of the outer wire W ₁ is provided on the side surface, and an inner wire is placed at the bottom of this bottomed circular hole.
A substantially cylindrical outer receiver 14 having a through hole (not shown) through which the wire W ₁ can be inserted is rotatably attached to a predetermined position at the tip of the swing arm 13, and the outer wire W ₁ is received in the outer receiver 14. It's good to force it. The reason why the outer receiver 14 can be pivoted in this manner is that, as is clear from FIGS. 3 to 5, although the swinging arm 13 swings, the pulling direction of the wire W hardly changes. In view of this, this is to prevent stress from being applied to the inner wire _W2 . This is especially necessary when using a push-pull type inner wire _W2 .

The end of the inner wire W ₂ protruding toward the front of the bicycle from the outer wire W ₁ fixes a part of the fixing member 1 to the support piece 1 a extending forward from the outer receiver 14 . In order to fasten the inner wire W ₂ , a known fastening means such as clamping the end of the wire W ₂ using a screwing means may be used. It is preferable to configure it as follows.

In the present invention _{, the} pantograph mechanism A
Since the wire W is intended to be driven to deform, the method of fastening the wire W is not limited to the above-mentioned method. You may. As a wire fixing method other than the illustrated example, for example, the wire W is introduced from the front of the bicycle in the opposite direction to the illustrated example, and an outer receiver 14 is attached to the support piece 1a corresponding to the inner wire fixing part in the figure. There is a method of fixing an inner wire to the end of the attached swing arm 13. In this way, the inner wire _W2 can be drawn directly from the front of the bicycle, further improving the mechanical efficiency of the transmission.

A locking pin 17 that locks one end of a first spring 16 for biasing the arm 13 in a direction away from the outer link 6 is protrudingly provided on the upper surface of the approximately central portion of the swing arm 13 . The first spring 16 is a coil spring formed by winding an elastic wire.
3 is inserted into the pin 4 which is pivotally connected.

Reference numeral 18 denotes a first spring holding member that serves to restrict the rotation range of the swing arm 13 to a certain range and to restrict the elastic action range of the first spring 16 on the swing arm 13. That is, in the present invention, only when the swinging arm rotates within a certain angle range b on the side closer to the outer link 6 within the rotatable angle range a of the swinging arm 13, the first spring 16 The elastic force acts on the swing arm 13, and when the swing arm rotates within the remaining rotation angle range c, the elastic force does not act on the swing arm 13.

The first spring holding member 18 is fixedly attached to the inner side of the outer link 6. In the illustrated example, one free end 16a of the first spring 16 is attached to a wall 18a located inside the outer link 6.
is fixed, and the base of the other open end 16b of the first spring 16 is locked to a locking pin 19 protruding from the bottom wall 18b extending near the center of the swing arm 13. As a result, both open ends 16a and 16b of the first spring 16 are narrowed within a predetermined angle.

Further, the first spring holding member 18 is engaged with the locking pin 17 of the swing arm 13 to define a rotation end at which the swing arm 13 is separated from the outer link 6 to the maximum extent. A stopper 20 is provided for this purpose.

Therefore, the swing arm 13 moves within the angular range b.
When rotating within the first spring, the released end 1 of the first spring
6b is a locking pin 17 provided on the swing arm 13.
The swinging arm 13 is engaged only with the first spring 16
(see FIGS. 5 and 4), but when the swing arm 13 is rotating within the angular range c, the release end 16b is It engages only with the locking pin 19 and does not engage with the locking pin 17 on the swing arm side, so that the swing arm 13 is not subjected to the elastic force of the first spring 16.

In the illustrated example, the first spring holding member 18 and the outer link 6 are formed separately, but they may be formed integrally by partially extending the outer link 6 or the like.

Reference numeral 21 denotes a second mechanism that deforms and energizes the pantograph mechanism A in a direction (direction of arrow L) opposite to the deformation direction (direction of arrow T) of pantograph mechanism A when the wire is pulled (direction P in FIG. 3). The spring has a smaller elasticity than the first spring 16. In the illustrated example, the second spring 21 is a coil spring energized to separate the movable member 7 and the outer link 6 from each other, and is inserted into the pin 9 that joins the movable member 7 and the outer link 6. In addition to this, the second spring 21 may be configured such that the movable member 7 and the inner link 5 are brought close to each other, or the inner link 5 and the fixed member 1
They may be separated from each other. Also, if there is enough space, fixing member 1 and outer link 6
and may be placed close to each other.

Next, with reference to FIGS. 3 to 6, the operation of the external bicycle transmission according to the present invention during normal gear shifting operation and when the saver function is exerted will be explained.

FIG. 3 shows the pull type wire when the pulling force is relaxed, and the push-pull type wire when pushed to the maximum extent. At this time, the function of the first spring 16 as a spring is blocked by the pin 19, and the pantograph mechanism A is deformed in the direction of the arrow L by the elasticity of the second spring 21.

Now, when the operating lever is operated to pull the inner wire W ₂ in the direction of the arrow P, the end of the inner wire W ₂ is fixed to the fixing member 1, so the outer wire W ₁ moves forward in the direction of the arrow Q. , which causes the swinging arm 13 to rotate in the direction of arrow R with respect to the fixed member 1. At this time, the locking pin 17
attempts to deform the first spring 16 by pushing the open end 16b of the first spring 16, but since the elasticity of the first spring 16 is greater than the elasticity of the second spring 21. , the second spring 21 is deformed, and the pantograph mechanism A is deformed in the direction of arrow T, as shown in FIG. 5, and the second spring 21 is in the accumulation state. The behavior of this pantograph mechanism A is as follows:
The same applies when a pull-type inner wire is used or a push-pull type inner wire is used.

Next, from the state shown in FIG. 5, if the pulling force of the pull-type inner wire is loosened, or if the push-pull type inner wire is pushed, the outer wire W ₁ will become the same regardless of which wire is used. It moves backward in the direction of arrow P, and at the same time, the swing arm 13 rotates in the direction of arrow S. To explain this in detail for each case, when the pulling force of the pull-type inner wire W ₂ is relaxed, the force with which the locking pin 17 of the swing arm 13 presses the end portion 16b of the first spring 16 is released, and the pantograph mechanism A is The force that tries to maintain a constant state in equilibrium with the elasticity of the second spring 21 is eliminated, and the external force applied to the pantograph mechanism A is only the stored force of the second spring 21. Therefore, the pantograph mechanism moves in the direction of arrow L,
Following the rotation of the outer link 6 to the spring end 16b in the direction of the arrow S, the swing arm 13 also rotates in the direction of the arrow S.
direction and return to the state shown in FIG.

When the push-pull type inner wire _W2 is pushed, the outer wire _W1 retreats in the direction of arrow P, and the swing arm 13 rotates in the direction of arrow S. At this time, the locking pin 17 is attached to the spring end 16b.
move away from or attempt to move away from. Therefore, the balance between the force of the locking pin 17 pressing the spring end 16b and the stored force of the second spring 21 is broken, and the pantograph mechanism Due to the difference in the force pressing 16b, the arrow L
direction and returns to the state shown in FIG.

Next, the effect when the saver function is activated will be explained.

When the inner wire W ₂ is pulled from the state shown in FIG. 3, the swinging arm 13 rotates in the direction of arrow R, but since the pantograph mechanism A is in an undeformable state, only the swinging arm 13 is connected to the outer link. 6 (in the direction of arrow R), the engagement pin 17 presses the spring end 16b and stores the spring, as shown in FIG.

When the bicycle starts from this state and the pantograph mechanism A becomes deformable, the absolute position of the swing arm 13 remains unchanged due to the traction action of the wire W ₂ , and the elasticity of the first spring 16 is equal to that of the second spring 21 . Since it is stronger than the elasticity, the first spring 6 opposes the elasticity of the second spring 21 and rotates the outer link 6 in the direction of the arrow, and accordingly, the pantograph mechanism A automatically deforms in the direction of the arrow L. The result is as shown in FIG. This behavior is the same whether a pull type inner wire is used or a push/pull type inner wire is used.

Next, the operation of the saver mechanism will be explained when the pulling force of the wire _W2 is relaxed from the wire W2 pulling state shown in FIG. 5, or when the wire is pushed in the case of a push-pull wire.

First, when a pull-type wire is used as the inner wire _W2 , when the pulling force of the inner wire _W2 is relaxed from the state shown in FIG.
Since the pressing force of the locking pin 17 of No. 3 pressing the end portion 16b of the first spring 16 in the direction of the arrow R is released,
Normally, the pantograph mechanism A should deform in the L direction as shown in FIG. 3 due to the stored force of the second spring 21, but since the pantograph mechanism A is in a state where it cannot deform, no deformation takes place. .

When the bicycle starts from this state and the pantograph mechanism A becomes deformable, the only external force applied to the pantograph mechanism A is the stored force of the second spring 21, so the pantograph mechanism A automatically moves toward the arrow It is deformed in the direction shown in FIG.

Next, push the inner wire W ₂ .
When a pull-type wire is used, when the inner wire W _{2 is pushed and operated from the state shown in FIG. 5, the end of the inner wire W 2 is} fixed to the fixing member 1, so the outer wire W ₁ is , the swing arm 13 rotates in the direction of arrow S,
The locking pin 17 of the swing arm 13 is connected to the spring end 16
b, away from both ends 16a, 16b of the first spring 16
is locked to the locking pin 19 integrated with the outer link 6 and the inner wall of the outer link 6 or the inner wall of the spring holding member 18, so the elasticity of the first spring 16 no longer contributes to the deformation of the pantograph mechanism A. . Therefore, the external force applied to the pantograph mechanism A is only the stored force of the second spring 21. However, since the pantograph mechanism A is in an undeformable state, the pantograph mechanism A does not deform even though the stored force of the second spring 21 acts. Next, as the bicycle develops and the pantograph mechanism A becomes deformable, the pantograph mechanism A is automatically deformed in the direction of arrow L by the action of the second spring 21, resulting in the state shown in FIG. 3.

In this way, when the swing arm 13 rotates within the fixed angle range b on the side closer to the outer link 6 within the rotatable angle range a of the swing arm 13, the locking pin 17 is moved by the first spring. The first spring 16 can be elastically contacted with the end portion 16b of the spring 16 to store the force of the first spring 16, and
The swing arm 1 moves within the remaining angular range c of the range b.
3 rotates, the locking pin 17 separates from the end 16b of the first spring 16, thereby providing a saver when the state shown in FIG. 5 changes to the state shown in FIG. 3. For the first time, it has become possible to perform this function both when using a so-called pull-type inner wire and when using a so-called push-pull type inner wire.

In the embodiment shown in the drawings, the swing arm 13 is pivotally supported on the outer link 6, and the first spring 16 is provided at the base end of the swing arm 13 on the outer link 6 side. Moving arm 13 and first spring 16
can also be provided on the inner link side. in this case,
The structure is similar to that shown in FIG. 5, which is vertically symmetrical.
Further, by doing so, it is possible to freely select and manufacture a so-called top normal type transmission and a low normal type transmission.

As described above, the bicycle exterior derailleur according to the present invention has a simple structure, can use either a pull-type or push-pull type inner wire, and has a saver function. This has a remarkable effect.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a partially cutaway front view, Fig. 2 is a perspective view of the main parts taken out, and Figs. 3 to 6 omit inner links. FIG. DESCRIPTION OF SYMBOLS 1... Fixed member, 5... Inner link, 6... Outer link, 7... Movable member, 10... Chain guide member, 13... Swinging arm, 16... First spring, 2
1... Second spring, A... Pantograph mechanism, W...
...operating wire.

Claims (1)

[Scope of utility model registration request] A pantograph mechanism A formed by linking a fixed member 1, an inner link 5, an outer link 6, and a movable member 7 in a parallelogram shape is deformed by an operating wire W, and a chain guide member 10 is attached to the movable member 7.
In the external bicycle transmission configured to be able to move in parallel, a swinging arm 13 is pivotally attached to the inner link 5 or the outer link 6 so as to be rotatable in the approaching and separating directions at a predetermined angle, and the swinging arm 13 A first spring 16 is provided for biasing the pivot arm 13 to rotate in a direction away from the inner link 5 or the outer link 6 to which it is pivotally attached, and within the rotation angle range of the swing arm 13, A certain angular range near the inner link 5 or outer link 6 to which the swinging arm 13 is pivoted is defined as the range in which the swinging arm 13 receives the biasing force of the first spring 16, and the remaining angular range is a range in which the swinging arm 13 does not receive the biasing force of the first spring 16, while the swinging arm 13 is set in a range where the swinging arm 13 does not receive the biasing force of the first spring 16, and when the operating wire W is pulled, the swinging arm 13
The spring is configured to rotate apart from and rotate against the spring, and is further configured to deform and bias the pantograph mechanism A in a direction opposite to the deformation direction of the pantograph mechanism A when the operation wire W is pulled. a second spring 21 having a smaller elasticity than the first spring 16;
An external bicycle transmission characterized by being provided with.