JPS6322791A - Rear derailer for bicycle - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a rear derailleur for bicycles. Sprocket.

This invention relates to a rear derailleur for bicycles that changes speed by changing a chain to one sprocket of a bicycle gear.

(Prior art) Generally, this type of derailleur is
As described in Japanese Patent No. 229, a derailleur main body is formed by a link mechanism consisting of a support member, a pair of link members, and a movable member, and the movable member of the derailleur main body is connected to each pulley and a pair of movable members. The chain guide is configured by pivoting the right plate of a chain guide consisting of a right plate and a left plate, and is arranged axially outward of the smallest diameter sprocket in a multi-stage sprocket device attached to a rear wheel hub of a bicycle. A chain is mounted on a frame that supports a rear wheel via a support member, and is hung from a front gear provided on a crank having a pedal to the multi-stage sprocket device, and is hung from the tenncon pulley to the guide pulley. By pulling the operation wire, the movable member is moved toward the large-diameter sprocket against the force of a return spring provided in the derailleur body, and by the restoring action of this spring, the movable member is moved toward the small-diameter sprocket, and the chain is moved. It is designed to replace one sprocket in a multi-stage sprocket device.

Further, on the guide pulley side of the right plate of the chain guide device, a chain pressing portion extending outward from the outer diameter position of the guide pulley in the direction of the multistage sprocket device is provided to push the chain toward the small diameter sprocket side. In addition, on the guide pulley side of the left plate, there is a sprocket that extends outward from the outer diameter position of the guide pulley and is connected to the chain from the guide pulley. A guard is provided to prevent it from falling off completely.

The guard portion of the left plate is preferably provided over the chain advance side portion of the guide pulley, but especially when used with a multi-stage sprocket device in which the diameter difference between adjacent large-diameter sprockets is large, the guard portion of the left plate If the guard part of the left plate is provided from the chain entry side part to the chain advance part of the guide pulley, when changing the chain from the small diameter sprocket to the large diameter sprocket, the guard part of the left plate will It comes into contact with the side surface of the part radially inward from the peak of the large diameter sprocket and prevents movement of the chain guide, making it impossible to change the chain to the desired large diameter sprocket. It is.

Therefore, when used with Biff (a multi-stage sprocket with a large diameter difference between adjacent large-diameter sprockets), conventionally,
The guard portion of the left plate is sized to face only the chain entry side portion of the guide pulley.

(Problem to be Solved by the Invention) However, in the above-described shift system, the shift control lever is moved forward against the return spring of the rear derailleur, and the chain is replaced with a large-diameter sprocket. If the operating lever unexpectedly rotates to the backward movement side due to vibrations from the bicycle or contact with another object, the operating wire will warm up and the chain guide will be able to connect to the large diameter sprocket due to the restoring action of the return spring. It will move from the corresponding position to the position corresponding to the small diameter sprocket.

As a result, the hanging portion of the chain on the chain guide moves toward the small diameter sprocket together with the chain guide, while the hanging portion of the chain on the large diameter sprocket moves
Since the chain tends to remain on the large-diameter sprocket on which the chain hangs, the chain tilts significantly between the large-diameter sprocket and the guide pulley. Therefore,
At this time, if the multi-stage sprocket device rotates in the reverse direction by inadvertently stepping on the pedal in the opposite direction or by inadvertently backing up the bicycle, the chain will move in the reverse direction while being tilted.
Even if the chain fell off from the chain advance side portion of the guide pulley toward the left plate side, that is, the large-diameter sprocket side, and then the multi-stage sprocket device rotated in the normal direction, the dropped chain returned extremely poorly. Further, in some cases, the dropped chain may become locked between the guard portion of the left plate and the chain entry side portion of the guide pulley. In this case, with the chain in the locked state, the multi-stage sprocket
When fZj rotates forward, the guide pulley does not rotate freely due to the locked chain, so the forward rotational force at position B of the multi-stage sprocket acts on the derailleur body via the chain guide, causing the derailleur to There was a problem in that the derailleur was damaged due to excessive force.

An object of the present invention is to provide a rear derailleur that can shift gears even when used with a multi-stage sprocket device in which the diameter difference between adjacent large-diameter sprockets is large. If the chain 7 accidentally falls off from the chain advancing side part of the guide pulley, the dropped chain 7 can be automatically returned to the chain advancing side part of the guide pulley by forward rotation of the multi-stage sprocket device. .

Means for Solving Problem C) Therefore, the present invention provides a guide pulley (51), a tension pulley (52), and these pulleys (51) (5).
The rear derailleur is equipped with a chain guide (5) consisting of a plate (53) supporting the guide pulley (2) and a chain guide (5) that changes gears by replacing the chain 7 with one sprocket of a multi-stage sprocket device on a bicycle. A guard f% (71) is provided at an axially outward position of the guide pulley (51) to prevent the chain 7 from falling off, facing the chain entry side portion (51a), and the multi-stage sprocket 7) When the Z position is reversed, the chain 7 that has fallen off from the chain advance side portion (51 b) of the guide pulley (51) is received, and the chain 7 is moved to the chain of the guide pulley (51) by normal rotation of the multi-stage sprocket device. A return body (7) for returning to the advancing side portion (51b) is provided movably along the moving direction of the check 7.

(Function) The gear shift control lever is moved forward against the return spring of the rear derailleur, and the chain guide unexpectedly moves to a position corresponding to the small diameter sprocket in a gear shifting system in which chain 7 is hooked to the large diameter sprocket. However, when the multi-stage sprocket device rotates in the reverse direction in this state, the chain 7 falls off from the chain advance side portion (51 b) of the guide pulley (51) to the return body (7), and and the guide pulley (51) may become locked. When the multi-stage sprocket device rotates in the forward direction with this chain 7 in the locked state, the return body (7) is pivotally mounted as shown in Fig. 1.3, for example, and becomes swingable. Therefore, the locked check 7 is pulled by the rotational force of the multi-stage sprocket device,
The guide pulley (51) and the return body (7) rotate together with this check 7, and as a result, the lock position of the check 7 is displaced in the direction of rotation of the guide pulley (51), and the return The body (7) moves the chain 7 to the chain advancing side portion (51) of the guide pulley (51).
b) can be automatically restored.

(Example) The illustrated derailleur is a support member (2) attached to a fork end (H) of a bicycle frame via a horizontal shaft (1).
) and a movable member (4) that is swingably connected to the support member (2) via a pair of link members (3), A guide pulley (51), a tension pulley (52), and a right pulley (5) that supports these pulleys (51) and (52).
3) The above-mentioned right play of the chain guide (5) consisting of
(53) is attached via the horizontal shaft (6), and this derailleur is installed axially outward of the small diameter sprocket in the multi-stage sprocket device (S) attached to the rear wheel of the bicycle. The chain guide (5) is arranged radially outward of the multi-stage sprocket device (S). Then, the chain 7 (C) is hung on the guide pulley (51) and the tension pulley (52), and the movable member (4) is pulled against the force of a return spring (not shown) by pulling the operation wire. Then, the guide pulley (51
) and Che 7 (
C) is replaced with one sprocket of the multi-stage sprocket device (S).

The right play (53) consists of a plate extending in the radial direction of the multi-stage sprocket unit U (S), and is connected to both longitudinal ends of the plate through a pair of pulley shafts (54) and (55). The movable pulley (51) and (52) are pivotally supported, and the movable pulley is located at the support side end of the guide boo U-(51) and at a position displaced from the support position of the guide boo 'J-(51). The horizontal shaft (6) pivotally supported on the member (4) is attached, and each of the pulleys (51
) (52), the guide pulley (51) is equipped with a multi-stage sprocket! (S), and the tension pulley (52) is placed on the side away from the guide pulley (S). 51) to the multi-stage sprocket device (S), and a tension spring (not shown) is interposed between the right plate (53) and the movable member (4), and the action of this spring is This urges the chain guide (5) clockwise in FIG.

In the embodiment shown in FIGS. 1 to 5, the guide pulley (
51), which has a guard part (71) opposite to the chain entrance part (51a) to prevent the chain (C) from falling off from the chain entrance part (51a), and has a guard part (71) that prevents the chain (C) from falling off from the chain entrance part (51a); When reversing, the guide boo IJ-(5
The chain 7 that has fallen off from the chain advancement side portion (51 b) in 1) is received, and the chain 7 (C) is moved to the guide boo U-(
The return stopper (7) that returns to the chain advancing side portion (51b) in 51) is provided so as to be rotatable along the moving direction of the chain 7(C).

In the above configuration, the return member (7) is made of a metal plate having the guard portion (71) at one end and a mounting hole (72) at the other end. It is pivotally supported on the pulley shaft (54) so that it can be rotated in the direction of movement of the chain 7 (C). In addition, this return mechanism (7) removes the chain 7 that has fallen off from the chain advance side portion of the guide pulley (51) and returns it to the guide pulley (51).
) so that it is received at an upper position (in the direction of the chain advancing side portion) with respect to the axis of the chain 7, and when the chain 7 is pulled in the forward movement direction due to normal rotation of the multi-stage sprocket device, the (7) is configured to rotate in the forward movement direction of the check 7.

In addition, the said return outside (7) is an auxiliary|assistant which is oriented in the direction opposite to the said guard part (71) via the connecting piece (73) at the edge of the said guard part (71), as shown in FIGS. 2 and 3. piece (74
) is integrally provided, and the free end side portion of this auxiliary piece (74) is opposed to the axially inner surface of the guide boo U-(51) with a slight interval, and the axially The deflection may be restricted by the inner surface of the guide boo U-(51).

Further, the return outside (7) moves from the approach side portion (51a) to the advance side portion (51b) with respect to the right plate (53).
), and the right plate (5
3) is provided with a pair of strokes and bars (8) and (9) for regulating the rotation of the return outside (7), and also between the return outside (7) and the right plate (53). A return spring (1o) is provided between the return springs (1o) for biasing the return outside (7) in the direction of the tension boob U-(52).

In addition, (11) and (12) in the figure indicate that the above is Idbu IJ-(5
1) It is a shallow bowl-shaped cup held on both sides. still,
These cups (11) and (12) may be formed integrally with the return shell (7).

The present invention is constructed as described above, and the guide boo U-(
The guide pulley (51) is located at an axially outward position of the guide pulley (51).
) A return body (7) having a guard part (71) opposite to the chain entry side part (51a) to prevent the chain from falling off.
, it is possible to prevent the chain from completely falling off the guide boo U-(51) when the chain is hung, and the return body (7) is attached to the guide pulley (
Since the structure has a guard part (71) facing the chain entry side part (51a) in 51), when used with a multi-stage sprocket device in which the diameter difference between adjacent large-diameter sprockets is large, the chain is This allows the side sprocket to be reliably replaced with the desired larger diameter sprocket.

In addition, in a gear shifting system in which the gear shifting operation lever is moved forward against the return spring and the chain (C) is replaced with a large-diameter sprocket, the operating lever is operated in a forward motion against the vibrations of the bicycle.
Alternatively, if the operating wire becomes loose due to unexpected rotation to the backward movement side due to contact with another object, the part of the chain (C) that hangs over each of the pulleys (51) and (52) may ) and move to the small diameter sprocket side,
Since the part of the chain that hangs onto the large-diameter sprocket tends to remain on the large-diameter sprocket, the chain (C)
It is inclined in the axial direction between the large diameter sprocket and the guide pulley (51).

Therefore, at this time, when the multi-stage sprocket device (S) is reversed by pressing the pedal in the opposite direction or by moving the bicycle backwards, the chain hooked on the large diameter sprocket moves backward in an inclined state, and the guide pulley ( 51) from the chain advance side portion (51 b) to the return body (7
) may fall off to the guard part (71) side of the return body (7) and become locked between the guard part (71) of the return body (7) and the guide boo U-(51).

In this case, the return body (7) is supported by the pulley shaft (54) and is rotatable relative to the right play (53), so the chain (C) is in a locked state. When the multi-stage sprocket device (S) rotates in the forward direction, the locked chain is pulled by the rotational force of the multi-stage sprocket device (S), and the guide boo IJ- (51) and return body (7) are pulled together with this chain. It will rotate as a unit. As a result, the lock position of the chain is displaced in the direction of rotation of the guide pulley (51), so the chain (C) is moved by the return body (7) to the chain advancing side portion (51) of the guide pulley (51).
b) can be automatically restored, and
If the dropped chain is not in the locked state as described above, it is easy to return the chain to the guide pulley (51) by rotating the return body (7).

Further, the return body (7) comes into contact with the stopper (9) and stops rotating, and the chain (C)
The return body (7) is returned to its original position, that is, the position where it contacts the stopper (8), by the restoring action of the return spring (10). That's what I do.

In the above embodiment, the guide pulley (51) of the chain guide (5) is composed of the guide pulley (51), the tensigon pulley (52), and the right play (53).
), a return body (7) is pivotally supported on a pulley shaft (54) that supports the guide pulley (51).
It was also used as the left plate installed at the axially inner position of the
In addition, as shown in FIG. 6, the right plate (53) of the chain guide is provided with the right plate (53) and the left plate.
or left play) (58) may support the returning body (7). In addition, this return body (7) is not only provided concentrically with the axis of the guide boo 'J- (51) as shown in Fig. 3, but also supported at an eccentric position displaced with respect to the axis as shown in Fig. 6, for example. It's okay. In this case, when the multi-stage sprocket device rotates forward with the chain locked between the return body (7) and the guide pulley (51), the lock point of the chain is between the return body (7) and the guide pulley (51). 51), which makes forward rotation of the multi-stage sprocket and device somewhat difficult, but there is no problem with returning the chain. Further, the return body (7) is rotatably provided, and
As shown in FIG. 7, it may be provided on either the right plate (53) or the left plate so as to be slidable in the direction of movement of the chain (C). In FIG. 7, (53a) is a guide hole provided in the right plate (53), and (75) is a support pin provided in the return body (7).

In addition, in the embodiment described above, the right plate (53) has
In addition to supporting the pulleys (51) and (52), the left plate is swingably supported with respect to the movable member (4), and the pulleys (51) and (52) are supported on the left plate.
52) may be supported.

(Effects of the Invention) As described above, the present invention prevents the chain from falling off by placing the guide pulley (51) at an axially outward position facing the chain entry side portion (51a) of the guide pulley (51). It has a guard part (71), and when the multi-stage sprocket device reverses, it receives the chain that has fallen off from the chain advance side portion (51 b) of the guide pulley (51), and when the multi-stage sprocket device rotates in the normal direction, the chain Since the returning body (7) for returning the chain to the chain advancing side portion (51 b) of the guide pulley (51) is provided movably along the moving direction of the chain, the chain is not removed from the guide pulley (51). It is possible to prevent the chain from completely falling off, and even when used with a multi-stage sprocket device in which there is a large diameter difference between adjacent large-diameter sprockets, the chain can be reliably replaced with the large-diameter sprocket. Due to the reverse rotation of the device, the chain that has fallen off from the chain advance side portion (51b) of the guide pulley (51) is returned to the return body (7).
When the guard portion (71) of the guide boo U-(51) becomes locked with the chain entry Ω portion (51a), normal rotation of the multi-stage sprocket device causes
The guide pulley (5) together with the chain in the locked state
1) and the return body (7) to displace the lock position in the normal movement direction of the chain, the chain is automatically moved to the chain advancing side portion (51 b) of the guide pulley (51). This allows the derailleur to be restored to normal condition and prevents damage to the derailleur.

Furthermore, even if the dropped chain is not locked, the dropped chain can be fixed to the guide boo U-(51).
It is easy to restore the condition.

[Brief explanation of drawings]

Fig. 1 is a rear view of only the main parts showing the derailleur of the present invention in use, Fig. 2 is a perspective view of only the return body, Fig. 3 is a sectional view of only the main parts, and Fig. 4 is the entire derailleur. front view of,
FIG. 5 and FIG. 7 are explanatory diagrams showing another embodiment. (5)...Chain guide (51)...Guide pulley (51a)...Chain entry side part (51b)
...Chain advancement side part (52) ...Tension pulley (53) ...Plate (7) ...Return body (71) ...・Guard part

Claims (1)

[Claims] A chain guide (5) consisting of a guide pulley (51), a tension pulley (52), and a plate (53) that supports these pulleys (51) and (52).
A rear derailleur that changes gears by changing a chain to one sprocket of a multi-stage sprocket device for a bicycle, the rear derailleur comprising: a chain entry side of the guide pulley (51) at a position axially outward of the guide pulley (51); It has a guard part (71) opposite to the part (51a) to prevent the chain from falling off, and the guard part (71) prevents the chain from falling off from the chain advancing side part (51b) of the guide pulley (51) when the multi-stage sprocket device is reversed. Acceptance,
Normal rotation of the multi-stage sprocket device moves the chain to the chain advancing side portion (51) of the guide pulley (51).
A bicycle rear derailleur characterized in that a return body (7) for returning to the chain (51b) is provided so as to be movable along the moving direction of the chain.