JPH0143994Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention is a front derailleur for a bicycle, more specifically, a rocking member having a chain guide is supported on a band member fixed to a seat tube of a bicycle frame. This invention relates to a bicycle front derailleur in which a chain guided by a chain guide is replaced with one front gear of a multi-stage front gear device to change gears.

(Prior art) Conventionally, as this type of derailleur,
As described in Publication No. 42155, a substantially C-shaped band body wrapped around the seat tube, a pair of tightening pieces protruding outward from opposite ends of the band body, and these tightening pieces are provided. It consists of a band member equipped with a tightening screw for tightening the sheet tube, and one swinging member provided with a chain guide at one end, and the diameter of the band member is reduced by rotation of the tightening screw and attached to the seat tube. At the same time, the band main body is provided with a pair of mounting pieces each having a through hole, and the swinging member is rotatably mounted to these mounting pieces via a single pivot shaft. A structure has been proposed in which the swinging member is rocked by a pulling operation of an operating wire attached to the end, and the chain guided by the chain guide is connected to one front gear of a multi-stage front gear device to change speed.

(Problem to be solved by the invention) However, in the case of this conventional structure, it is necessary to provide an attachment structure for the band member to the seat tube and an attachment structure for the rocking member to the band member, so the structure is complicated. Not only that, but there is also a problem that the assembly is difficult and the cost increases as a whole.Furthermore, the structure for attaching the band member to the seat tube protrudes outward from the seat tube, resulting in an increase in size. However, there were problems in that it became a nuisance and also had a bad appearance.

The purpose of the present invention is to solve the conventional problem of having to provide separate mounting structures for the band member to the seat tube and the rocking member to the band member. By utilizing the mounting structure to the seat tube and making it possible to attach the band member and the rocking member at the same time, there is no need to provide a special mounting structure for the rocking member. I made sure that there was no such thing.

(Means for Solving the Problem) Therefore, a pair of clamping pieces projecting oppositely from both ends of a band body wrapped around a bicycle seat tube, and a tightening screw for tightening these clamping pieces. A swinging member is provided with a chain guide at one end, and the swinging member is provided with a pivot portion, and the swinging member is pivoted to the tightening screw so as to be able to swing within a certain range. It is something.

(Function) By wrapping the band body around the seat tube, supporting the pivoting part of the rocking member on the tightening screw of the band member, supporting this tightening screw between a pair of tightening pieces, and tightening it. reducing the diameter of the band body;
The band member is fixed to the seat tube, and the rocking member is supported by the band member so as to be freely rockable.

(Embodiment) An embodiment of the derailleur of the present invention will be described below based on the drawings.

In the figure, 1 is a substantially C-shaped band body 11 that is wound around a seat tube S of a bicycle frame;
a pair of first and second fastening pieces 12 and 13 protruding outward from both ends of the band body 11 in opposing directions;
It is a band member consisting of a tightening screw 14 that tightens these tightening pieces 12 and 13, and 2 is a swinging member having a chain guide 21 at one end, and the operating wire W is connected to the other end of this swinging member 2. In addition to providing the fixture 22, a pivot portion 23 having a through hole 23a is provided in the middle in the longitudinal direction, and this pivot portion 23 is pivotally attached to the tightening screw 14 so as to be able to swing within a certain range.
Further, 3 is a return spring, and this return spring 3 is wound around the tightening screw 14, one end of which is brought into contact with the first tightening piece 12, and the other end is locked with the swinging member 2. Thus, the rocking member 2 is biased in one direction.

The band member 1 is formed by punching and bending a metal plate, and a hinge 15 is provided at the center of the band body 11 in the bending direction.
Further, the tightening screws 14 are attached to the tightening pieces 12 and 13.
long holes 12a, 13 extending in a direction perpendicular to the axis of the
A is provided. Further, the first tightening piece 12 includes:
A cover 16 having a substantially U-shaped cross section is provided that protrudes inward from the three side edges and covers the coil portion 31 of the return spring 3, and furthermore, at the tip of this cover 16,
A closing piece 17 is provided facing the first tightening piece 12 and having an elongated hole 17a corresponding to the elongated hole 12a, while a retainer protrudes from the top end of the cover 16 in the direction of the second tightening piece 13. A protruding piece 18 is provided, and the holding piece 18 holds a pair of first and second adjusting screws 4 and 5 for regulating the swinging range of the swinging member 2. Further, the second fastening piece 13 has a collar 13 having a substantially U-shaped cross section and protruding inward from its three side edges.
b.

Moreover, the rocking member 2 has one end in its length direction,
A support piece 24 extends in the same direction as the axis of the tightening screw 14, and a support piece 24 extends from the tip of the support piece 24 to the tightening screw 1.
The closing piece 17 extends in a direction perpendicular to the axis of
and a mounting piece 25 facing the supporting piece 24.
The chain guide 21 is attached to the mounting piece 25, and a through hole 25a corresponding to the through hole 23a is provided in the mounting piece 25, and the tightening screw 14 is inserted into these through holes 23a, 25a. 1 facing the adjustment screws 4 and 5 on the mounting piece 25;
A catch seat 26 having a pair of abutting portions 26a and 26b is provided.

The chain guide 21 is composed of an inner plate 21a and an outer plate 21b facing each other, and the upper edges of the inner plate 21a and the outer plate 21b on one end in the length direction are attached to the support piece 24.

Further, the tightening screw 14 is a head bolt 14a.
and a headed nut body 14b having a screw hole 14c. is inserted into the nut body 14b to support the rocking member 2 on the first tightening piece 12 via the nut body 14b.
The return spring 3 is wound around the outer circumference of the bolt 14a, and the bolt 14a is wrapped around the second tightening piece 13.
It is inserted into the elongated hole 13a and screwed into the screw hole 14c of the nut body 14b.

Further, the return spring 3 includes a coil portion 31 and
It consists of a first locking piece 32 that projects outward in the radial direction from one end of the coil portion 31 and a second locking piece 33 that projects outward in the axial direction from the other end.
2 is brought into contact with the inner surface of the cover 16, the second locking piece 33 is projected outward from the elongated hole 17a of the closing piece 17 and is locked in the locking hole 25b provided in the mounting piece 25, and the swinging Component 2 is indicated by arrow X in FIG.
The abutting portion 2 of the rocking member 2 is normally
6a and 26b come into contact with the first adjusting screw 4, and the chain guide 21 is stopped at a position corresponding to the small diameter front gear of the multi-stage front gear device, so that the so-called low normal state is achieved.

Note that 6 in the figure is a sleeve that fits around the outer periphery of the nut body 14b.

The present invention is constructed as described above, and prior to attaching the bicycle frame to the seat tube S,
The rocking member 2 and the return spring 3 are supported on the band member 1 via the tightening screw 14, and then the band member 1 is fixed to the seat tube S.

That is, the pivot portion 23 and the mounting piece 25 of the rocking member 2
is arranged outside the first tightening piece 12 and the closing piece 17 in the band member 1, and the return spring 3
is placed in the cover 16, and the nut body 14b of the tightening screw 14 is inserted into the through hole 23a of the rocking member 2, the elongated hole 12a of the first tightening piece 12, inside the coil part 31 of the return spring 3, and in the closing piece 17. It is inserted into the elongated hole 17a and the through hole 25a of the attachment piece 25, and the rocking member 2 and return spring 3 are supported on the first tightening piece 12 via this nut body 14b. 11 is expanded around the hinge part 15,
Wrap it around the outer periphery of the seat tube S, and insert the bolt 14a of the tightening screw 14 into the elongated hole 13 of the second tightening piece 13.
a and insert the bolt 14a into the nut body 14.
It is screwed into the screw hole 14c of b.

By tightening this bolt 14a, the second tightening piece 13 is bent toward the first tightening piece 12, the diameter of the band body 11 is reduced, and the band member 1 is attached to the seat tube S. By attaching this band member 1, the swinging member 2 can be mounted to freely swing.

As described above, the tightening screw 14 for attaching the band member 1 to the seat tube S allows the rocking member 2
and the return spring 3 can be attached to the band member 1.
It is possible to eliminate a dedicated mounting structure, simplify the structure, and improve the ease of assembly. Second tightening piece 1
2, 13 and the tightening screw 14 do not protrude outward in the radial direction of the seat tube S from the position where they are displaced relative to the chain guide 21, so the overall size can be reduced, and the mounting structure of the band member 1 does not get in the way. Moreover, the appearance can be improved. Furthermore, by concealing the return spring 3 with the cover 16, it is possible to prevent dust, rainwater, etc. from getting on the return spring 3, improve the sealing performance of the return spring 3 portion, and further improve the appearance. It can be done well.

Further, the tightening screw 14 is inserted into the long holes 12a, 13 of the first and second tightening pieces 12, 13 and the closing piece 17.
The position of the chain guide 21 relative to the small-diameter front gear is adjusted by moving the seat tube S in the radial direction relative to the band member 1 within the ranges a and 17a. Therefore, in this case, there is no need to particularly adjust the first adjusting screw 4. or,
The return spring 3 causes the chain guide 21 to
is biased toward the large-diameter front gear, and the chain guide 21 normally stops at a position corresponding to the large-diameter front gear, which is the so-called top normal state, in which case the second adjusting screw 5 should be tightened. There is no need to make any special adjustments.

In the embodiment described above, the rocking member 2 and the return spring 3 are supported by the tightening screw 14, but the return spring 3 does not necessarily need to be supported by the tightening screw 14.

Further, as the tightening screw 14, the nut body 14b and the bolt 14a are used, and the rocking member 2 and the return spring 3 are supported on the nut body 14b, but in addition, only the bolt 14a may be used. In this case, for example, a screw hole may be provided in the first tightening piece 12, and the bolt may be screwed into the screw hole, and the rocking member 2 and return spring 3 may be directly supported on the bolt. Further, the first tightening piece 12 is integrally provided with a cylindrical body having a threaded hole, and the swinging member 2 and the return spring 3 are supported on the outer periphery of this cylindrical body, and the threaded hole of the cylindrical shaft is provided with a cylindrical body. The structure of the tightening screw 14 is not particularly limited, and the bolt may be configured to be screwed together. Also, the rocking member 2
The structure of is also not particularly limited.

Further, although the hinge 15 is provided on the band body 11 of the band member 1, other structures may be used without the hinge 15.

Furthermore, in the above configuration, the tightening screw 14
The chain guide 21 is provided horizontally in the front-rear direction of the bicycle, but in addition, the tightening screw 14 is oriented in the front-rear direction of the bicycle and is inclined so that its rear side is located above the front side.
When moving in the axial direction of the front gear,
The amount of displacement on the rear side of the chain guide 21 may be larger than the amount of displacement on the front side. By doing this, especially when changing the chain from a small-diameter front gear to a large-diameter front gear, the front side and the rear side change by the same amount of displacement due to a large displacement on the rear side of the chain guide 21 that guides the chain. Even if the stroke when operating the operating wire is constant, the chain can be quickly guided to the rear side where the amount of displacement is large, and the change to the large-diameter front gear can be performed quickly. be.

(Effects of the invention) As described above, the present invention utilizes the mounting structure of the band member to the seat tube, and attaches the swinging member having a chain guide at one end to the tightening screw of this mounting structure so as to be able to swing within a certain range. Because of this, it is possible to eliminate the need for a dedicated mounting structure for the rocking member to the band member, which simplifies the structure, and allows the band member and the rocking member to be attached at once by rotating a single tightening screw. Since it can be attached, ease of assembly can be achieved, and overall costs can be reduced.

Moreover, since the mounting structure can be prevented from protruding outward from the position displaced in the circumferential direction of the seat tube with respect to the chain guide, the overall size can be reduced and the mounting structure does not get in the way. Moreover, the appearance can be improved.

[Brief explanation of drawings]

Fig. 1 is an enlarged cross-sectional plan view with some parts omitted showing one embodiment of the derailleur of the present invention, Fig. 2 is a cross-sectional view taken along the line of Fig. 1, Fig. 3 is a cross-sectional view taken along the line of Fig. 1, and Fig. 4. is a perspective view. 1...Band member, 11...Band body, 1
2, 13...Tightening piece, 14...Tightening screw, 2...
Swing member, 21... chain guide, 23... pivot portion.

Claims (1)

[Scope of utility model registration request] A band member is provided with a pair of tightening pieces projecting oppositely from both ends of a band body to be wrapped around a seat tube of a bicycle, a tightening screw for tightening these tightening pieces, and a chain guide provided at one end. one rocking member, the rocking member is provided with a pivot joint,
A front derailleur for a bicycle, characterized in that the rocking member is pivotally connected to the tightening screw so that it can rock within a certain range.