JPS6251798B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chain-type external bicycle transmission using a multi-stage sprocket.

The applicant previously filed Japanese Patent Application No. 54-106587 (Japanese Unexamined Patent Publication No.
No. 56-31888), we proposed an external bicycle transmission. However, this transmission has a connecting shaft that connects the gear shift operating cam, the reel and spring that connects to the operating wire, the outer link of the parallel link, and the fixed member, and the outer link has a structure that covers the gear shift operating cam. As a result, the outer link protrudes significantly toward the outside of the bicycle, which could be dangerous if it comes into contact with another object.

The present invention has been made to improve the above-mentioned drawbacks, and includes a shaft for mounting a speed change operation cam, a reel for connecting to the operation wire, and a spring on the connecting shaft between the inner link of the parallel link and the fixed member. A lever, one end of which engages with the speed change operation cam, is provided on the connecting shaft between the fixed member and the outer link, and the other end of this lever is covered by the outer link, thereby reducing the amount of outward protrusion of the outer link. The purpose is to further improve the safety of bicycle riding.

In addition, by screwing a bolt to the other end of the lever and providing a hole in the outer link for inserting a tool to adjust the bolt, delicate chain line adjustments can be easily made from outside the outer link. The purpose is to

Embodiments of the present invention will be described below with reference to the drawings.
In the figure, 1 is a bicycle frame, 2 is a rear axle, 3 is a multi-stage sprocket rotatably fitted to the shaft 2, 4 is a chain, and 5 is a mounting bracket fixed to the shaft 2 with a nut 6.

In this embodiment, the plate material is bent into a U-shape to form the side plate parts 7a and 7b, and the fixing metal fitting 7, which has a tightening seat part 7c provided at the bent part, is attached via the tightening seat part 7c. It is fixed to the mounting bracket 5 with bolts 8, and an inner link connecting shaft hole 7d and an outer link connecting shaft hole 7e are provided in both side plates 7a and 7b of the fixing bracket 7, respectively, and the outside is covered with a cover 7'. Do it like this. Note that an adjuster receiver 10 is inserted between the fixing member 7 and the mounting bracket 5 through a spacer 9, and they are tightened together with bolts 8, and a gear shift operation wire (not shown) is connected to the adjuster receiver 10. Screw together the wire adjuster 11. 12 is the lock nut.

Also, both side plate portions 13a and 13b of the inner link 13
A connecting hole 13d for connecting to the fixed member 7 and a connecting hole 13e for connecting to the movable member 29 are provided in each of the connecting holes. 13c is a back plate that integrally connects both side plate parts 13a and 13b. Both side plate parts 13a, 1 of this inner link 13
A coil spring 14 and a speed change operation cam 15 are fitted between 3b, and a connecting shaft 17 is inserted through the fixed member 7 and the inner link 13, and a reel 18 is fitted to the end of the connecting shaft 17 that protrudes from the fixed member 7. and annular groove 17a
The retaining ring 19 fitted in the retaining ring 19 is prevented from coming off. Reference numeral 16 designates a hook pin of the spring 14 protruding from the cam 15, 18a represents a locking portion of an operating wire nipple (not shown) provided on the reel 18, and 20 represents a hook pin of the cam 15 for speed change operation provided protruding from the reel 18. Engagement protrusion 1
5a, and thereby the reel 18
The rotation of the cam 15 is transmitted to the cam 15. One end of the coil spring 14 is engaged with the hook pin 16 implanted in the speed change operation cam 15, and the other end is engaged with the fixing member 7, so that the speed change operation cam 15 is moved in the direction of the arrow G in FIG.
act to rotate it in the direction of .

The outer link 21 forming a parallel link with the inner link 13 is formed into a curved channel shape, and a connecting hole 21e is provided at the upper end of both side plate parts 21a, 21b, and a connecting hole 21 is provided at the lower end of each of the outer links 21.
Provide f. 21c is a back plate connecting the side plate parts 21a and 21b, 21d is a spring receiver formed by bending the inner edge of the side plate part 21b, and 21g is a hole provided in the back plate 21c for inserting an adjustment tool. . Then, the connecting hole 7e of the fixing member 7 and the connecting hole 21e of the outer link 21 are overlapped, and the connecting shaft 28 is inserted through the connecting hole 7e of the outer link 21.
A lever 22 and a coil spring 27 are fitted to a connecting shaft 28 between a and 21b.

At one end of the lever 22, a cam roller 24 that rolls in contact with the speed change operation cam 15 is pivotally supported by a pin 23, and at the other end of the lever 22, a bent piece 22a is provided. A bolt 25 fitted with a locking spring 26 is screwed into the threaded hole 22b. The head of the bolt 25 is brought into contact with the inner surface of the back plate 21c of the outer link 21, and the adjustment is made through the hole 21g drilled in the back plate 21c.
The diameter of 1g is made smaller than the head diameter of the bolt 25. Further, a movable member 29 forming a section of the parallel link is connected by a shaft 30 inserted into the connection hole 13e of the inner link 13 and a shaft 31 inserted into the connection hole 21f of the outer link 21, and a coil spring 32 is connected to the shaft 30. By fitting and acting in the direction of arrow B in FIG. 3, the movable member 29 is urged against the inner link 13 so as to always rotate clockwise.

Further, as shown in FIGS. 1 and 2, the guide wheel 33 of the chain 4 is pivotally supported by a shaft 34, and
As shown in FIG. 3, a shaft 38 is installed in the middle of a replacement frame 37 that pivotally supports the tension ring 35 by a shaft 36.
The movable member 29 is rotatably fitted to the vertical wall 29a, a coil spring 39 is fitted to the protrusion of the shaft 38, one end of the spring 39 is locked to the shaft 38, and the other end of the spring 39 is fixed to the shaft 38. By locking the movable member 29 to the movable member 29, the replacement frame 37 is urged to rotate in the direction of the arrow C about the shaft 38 in FIG. Note that 37' is an opposing plate of the hanging frame 37, 40 is a flat washer fitted to the end of the shaft 38, and 41 is a retaining ring thereof.

Next, the operation of the apparatus of the present invention constructed as described above will be explained.

Now, if the movable member 29 is in the high speed position as shown in FIG. ), the inner wire rotates the cam 15 via the reel 18 in the direction of arrow D in FIG. Then, the lever 22 in contact with the cam 15 rotates in the direction of arrow E. The lever 22 can be rotated in the direction of arrow E relative to the outer link 21 against the spring 27, but the spring 27 is
It is set with a force greater than the force required to replace it, so it will not bend. That is, the lever 22 and the outer link 21 can rotate together from the state shown in FIG. 3 to the state shown in FIG. 7. In this case, the spring 32 is deflected and the inner link 13 also rotates together with the outer link 21 as shown in FIG. 3, the chain 4 is replaced. FIG. 7 shows a state in which the chain 4 is replaced with the sprocket 3 at the lowest speed stage.

Also, the movable member 29 is in the low speed transmission position (seventh
(see figure), if the hanging frame 37 is movable when the crank is rotated, when the transmission wire is loosened by the operation tool, the reel 18 is rotated by the coil spring 14 and winds up the inner wire. Cam 1 at the same time
5 also rotates in the direction of arrow A in FIG. If the cam 15 rotates in the direction of arrow A in this way, the movable member 2
9 becomes movable, the force of the spring 32 causes the outer link 21 to try to rotate towards the high speed side, and the force of the spring 27 causes the lever 22 to also try to rotate in the direction of arrow F. Therefore, when the cam 15 rotates in the direction of arrow A, the lever 22 rotates in the direction of arrow F by the amount of the step caused by the rotation of the cam 15, and the inner and outer links 13 and 21 simultaneously move to the states shown in FIGS. 7 to 3. As a result, the movable member 29 moves to the high speed side, and the chain 4 is replaced with the sprocket 3 on the high speed side by the amount of the step of the cam 15.

Next, when the crank is stopped, chain 4
Since the movable member 29 cannot be replaced, the movable member 29 cannot be moved.

However, now that the movable member 29 is in the high-speed transmission position as shown in FIG. rotates in the direction of arrow D in FIG. In this case, since the movable member 29 cannot be moved, the inner and outer links 13 and 21 cannot naturally rotate. However, since the lever 22 can rotate in the direction of the arrow E with respect to the outer link 21 against the spring 27, the lever 22 rides on the steps of the cam 15 which are formed into a step-like shape due to the rotation of the cam 15.
Therefore, the head of the bolt 25 screwed into the bent piece 22a of the lever 22 is separated from the inner surface of the back plate 21c of the outer link 21, as shown in FIG. 8. i.e. link 1
The force that causes 3 and 21 to rotate toward the low speed side is stored in the coil spring 27. When the crank rotates in this state and the movable member 29 becomes movable, the force stored in the spring 27 acts over the spring 32, causing the links 13 and 21 to move so that the head of the bolt 25 of the lever 22 Rotate until it hits the inner surface of the back plate 21c as shown in FIG. In other words, the movable member 29 moves to the low speed side, and the chain 4 is changed to a stage on the low speed side by the difference in stage of the cam 15.

Furthermore, when the movable member 29 is in the low-speed transmission position as shown in FIG. 7, and when the crank is stopped and the movable member 29 cannot be moved, when the transmission wire is loosened by the operating tool, the coil spring 1
The inner wire is wound onto the reel 18 by the force 4, and at the same time the cam 15 rotates in the direction of arrow A. However, since the movable member 29 cannot be moved, the links 13, 21 and the lever 22
cannot rotate together. But cam 15
rotates in the direction of arrow A as shown in FIG. 9 from the state shown in FIG. 7, so that the roller 24 at the tip of the lever 22
A gap corresponding to the step due to the rotation of the cam is created between the cam 15 and the cam 15 as shown in FIG. 9. When the crank rotates in this state and the movable member 29 becomes movable, the link 1
3, 21 and the lever 22 are the roller 24 at the tip of the lever.
rotates until it hits the step on the outer circumferential surface of the cam 15,
The movable member 29 moves to the high speed side as shown in FIG. 3, and the chain 4 is replaced with the sprocket 3 on the high speed side by the amount of the step caused by the rotation of the cam 15.

Next, the effects of the device of the present invention will be explained. In the conventional transmission of this type, the speed change operation cam is provided on the connecting shaft between the outer link and the fixed member forming the parallel link, and the speed change operation cam is covered by the outer link. As a result of this outer link protruding largely outward from the bicycle, there is a drawback that it is dangerous for the bicycle to ride.

In contrast, in the present invention, the speed change operation cam 15 is provided on the connecting shaft 17 between the inner link 13 and the fixed member 7, and the lever 22 is pivotally supported by the connecting shaft 28 between the outer link 21 and the fixed member 7. In this way, the amount of outward protrusion of the outer link 21 is made smaller than that of the conventional one, which not only improves the safety of bicycle riding, but also makes the external transmission of the bicycle more compact and improves its appearance. It has an excellent effect.

Further, in the present invention, the bolt 25 is screwed onto the other end of the lever 22, and the bolt 25 is screwed onto the other end of the lever 22.
Since the outer link 21 is provided with a hole 21g for inserting a tool for adjusting the chain line 5, delicate chain line adjustments can be easily made from outside the outer link 21, which is very convenient.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the installed state of the exterior transmission of the present invention, Fig. 2 is a front view of the same as seen from the front, Fig. 3 is a sectional view showing the internal structure as seen from the back of Fig. Fig. 4 is a side view of Fig. 3 with the internal structure partially omitted, Fig. 5 is an exploded perspective view of the main parts of the device of the present invention, Fig. 6 is a detailed view of the speed change operation cam, and Fig. 7. ~FIG. 9 is an explanatory diagram of the operation of the apparatus of the present invention corresponding to FIG. 3. 1... Frame, 2... Rear axle, 3... Multi-stage sprocket, 4... Chain, 5... Mounting bracket, 6
...Nut, 7...Fixing member, 7'...Cover,
8... Bolt, 9... Spacer, 10... Adjuster holder, 11... Wire adjuster, 12... Lock nut, 13... Inner link, 14... Coil spring, 15... Cam for speed change operation, 16 ... Hook pin, 17 ... Connection shaft, 18 ... Reel, 19 ...
Retaining ring, 20...pin, 21...outer link, 2
2... Lever, 23... Pin, 24... Cam roller, 25... Bolt, 26... Locking spring,
27...Coil spring, 28...Connection shaft, 29...
Movable member, 30... shaft, 31... shaft, 32... coil spring, 33... guide wheel, 34... shaft, 35...
...Tension ring, 36...Shaft, 37...Replacement frame, 38...
...Shaft, 39...Coil spring, 40...Flat washer, 4
1...Retaining ring.

Claims (1)

[Claims] 1. In a device in which a replacement frame 37 supporting a guide wheel 33 and a tension rod 35 is rotatably attached to a movable member 29 connected to a fixed member 7 fixed to a frame 1 via parallel links 13 and 21, the fixed member A cam 15 for speed change operation and a spring 14 that urges the cam 15 to always rotate in one direction are provided on the connecting shaft 17 between the fixing member 7 and the inner link 13.
A lever 22 is pivotally supported on a connecting shaft 28 between the outer link 21 and the outer link 21, and one end of the lever 22 is connected to the speed change operation cam 15 by a spring force.
A bolt 25 screwed onto the other end of the lever 22 is removably engaged with the outer link 21, and a hole 21g for inserting a tool for adjusting the bolt 25 is provided in the outer link 21. is housed in the outer link 21, and the fixing member 7
A bicycle external transmission device is provided with a reel 18 that rotates together with a speed change operation cam 15 on a connecting shaft 17 with a more protruding inner link 13, and an inner wire of an operation wire is connected to this reel 18.