GB2180602A

GB2180602A - Moped clutch and transmission

Info

Publication number: GB2180602A
Application number: GB08522947A
Authority: GB
Inventors: Gin Yung Lim; Sei Tei Wang
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-09-17
Filing date: 1985-09-17
Publication date: 1987-04-01
Also published as: GB8522947D0

Abstract

A moped is provided with power means which drives the rear wheel of the moped through a gear assembly, a clutch assembly 30 and a chain transmission means. The gear assembly and the clutch assembly are mounted in a housing 20, Fig. 2, which can be easily attached to the intermediate portion of the moped frame. The chain transmission means includes a chain wheel 26 driven by one gear 24, another chain wheel mounted on a crank shaft 45 of the pedals and a further chain wheel attached to the rear wheel assembly. The clutch assembly connects and disconnects gear 24 and chain wheel 26 and includes a truncated cone-shaped member 33. Fig. 1, having spaced axial ribs 331. The member 33 is biased by a spring 34 in a first direction in which it forces lining blocks 32 radially outwardly against the inner wall of a hollow member 241 to engage the clutch. A cable is actuated in a second opposed direction to move the member 33 to free the clutch. <IMAGE>

Description

SPECIFICATION Drive mechanism for a moped This invention relates to a moped and particularly to a drive mechanism of a moped.

It is a common practice to convert a bicycle into a moped by incorporating a drive mechanism including a power means, such as a motor or an engine with a conventional bicycle.

However, the drive mechanisms available in the past were not conveniently incorporated with a bicycle.

An object of the invention is to provide an improved drive mechanism which can be easily incorporated with a bicycle easily without changing any part of the original bicycle and without damaging it.

This and other objects can be achieved in accordance with the present invention through the provision of a drive mechanism mounted to the intermediate portion of the frame. It comprises a power means, a cylindrical housing mounted adjacent to the power means, a first gear member having a toothed annular portion of larger diameter and a hollow cylindrical body portion of smaller diameter provided in the housing. A first bearing member is provided between the inner side of the housing and the periphery of the hollow cylindrical body portion for mounting the first gear member in a rotatable position, and a second gear member for transmitting the output motion of said power means to the first gear member is meshed with said first gear member. A shaft member is mounted in the toothed annular portion in a position rotatable relative to the annular portion.A chain transmission means for transmitting the motion of the first gear member to the rear wheel includes a chain wheel mounted on the shaft member. There is a clutch assembly which includes a truncated cone-shaped member provided in said hollow portion in a coaxial position and is connected to said shaft for simultaneous rotation, said cone member having spaced apart axial ribs on it periphery.

Shoe members of segmented annulus-shaped cross-section surround said cone member and are spaced by the ribs. Shoe lining blocks of segmented annulus-shaped cross-section are provided around said shoe members and are in contact with the inner side of said hollow portion. Also provided are an extension spring biassing said cone member to move in a first direction which causes said shoe members and said lining blocks to expand radially so as to place said clutch assembly in the engaged position, a clutch cable connected to said cone member so as to pull it in a second direction opposite to said first direction, and a looped spring member incorporated in said lin ing blocks for contracting said lining blocks and said shoe members when said cone mem ber is pulled by said clutch cable.

The present exemplary preferred embodiment will be described in detail with reference to the following drawings, in which: Figure 1 is an exploded view of a drive mechanism according to the present invention; Figure 2 is a perspective view of a drive mechanism of Fig. 1; Figure 3 is a view of a bicycle incorporating the drive mechanism of Fig. 1; and Figure 4 is a sectional view of the drive mechanism of Fig. 2.

Referring to the drawings, there is shown a drive mechanism mounted on the frame of a moped between cross bar 11, seat tube 12 and down tube 13. The drive mechanism includes a power means 10 which can be a direct-current motor or an engine, a gear assembly, a clutch assembly 30 and a chain transmission assembly.

The gear assembly and the clutch assembly are mounted on a housing 20 which is attached to the frame adjacent to the power means 10 and has a rear cover 35 which is screwed to the. rear side of the housing 20. A gear 22 is connected to output shaft 22a of power means 10 and is mounted on an extension web 21 of the housing 20. Another gear 23 is mounted on the web 21 together with a bearing member 231 in a position in which it is meshed with the gear 23.

In the housing 20, a bearing assembly 242 is mounted with its outer periphery in contact with the inner side of the housing 20. A gear member 24, which has a toothed annular portion 243 of larger diameter and a cylindrical hollow portion 241 of smaller diameter, is mounted in the housing 20 in such a manner that the hollow portion 241 is sleeved by the bearing assembly 242. A shaft 25 is jour nalled in the gear member 24 through a bearing assembly 245. To the ends of the shaft 25 are fixed a circular plate 251 and a chain wheel 26 respectively.

The clutch assembly is provided in the hollow cylindrical portion 241. It includes a truncated cone-shaped member 33 which is in a coaxial relationship with the cylindrical portion 241, and three shoes 312 of segmented annulus-shaped cross section provided around the cone member 33, each shoe 312 having its end face abutting with and screwed to the plate 251 using screw holes 252 and 313.

Three lining blocks 32 of segmented annulusshaped cross-section are provided between shoes 312 and the inner surface of the hollow cylindrical portion 241. Each lining block 32 is provided with two arc-shaped grooves 324 each of which extends along the full length of each flat side thereof, a boss 321, and a lin ing face 323 at its outer periphery. Two looped springs 325 are put in two annular grooves formed by the combination of grooves 324 so as to contract lining blocks 32 around the shoes 312.

On the outer surface of the cone member 33 are provided three longitudinally extending ribs 331 which project between each two adjacent shoes 312, these ribs 331 being adapted so that their end faces push the bosses 321 of the lining blocks 32. The coneshaped member 33 has a through-hole 334 and a neck portion 332 at its larger end on which is sleeved a thrust bearing 333. A clutch cable 37 is connected to the cone member 33 with its end retained by the shoulder formation 371.

An extension spring 34 is provided in the hollow portion 352 of the rear cover 35 surrounding the clutch cable 37 and its one end abuts against the end face of the thrust bearing 333. Another end of the spring 34 is connected to an adjusting nut 36 provided in the hollow portion 352, the nut 36 having a central hole 361 to allow the cable 37 to extend out from the housing 20, and an external screw thread 362 which engages with the internal thread 353 of the hollow portion 352.

The chain wheel 26 is connected, through an endless chain 42, to a chain wheel 41 which is mounted on a crank shaft 45 coaxially with another chain wheel 44 for simultaneous rotation, the crank shaft 45 being adapted to hold cranks and pedals (not shown). A free-wheel 43 and an annular member 44a are provided between the crank shaft 45 and chain wheels 41 and 44. The chain wheel 44 is in turn connected to chain wheel 46 through a chain 47.

In operation, the location of the adjusting nut 36 is adjusted so as to maintain a particular tension in the spring 34 which pushes the cone member 33 towards the plate 251 of the shaft 25. When the cone member 33 is pushed by the spring 34, the assembly of shoes 312 will expand slightly in a radial di rection and the ribs 331 of the cone member 33 will push the bosses 321 of the lining blocks 32 forward, causing the lining blocks 32 to expand against the force of the springs 325 and abut against the inner side of the wall of the hollow portion 241. In this situation, the clutch assembly is in the position in which it establishes a mechanical connection between the gear member 24 and the shaft 25. The output motion of the engine 10 is transmitted to the chain wheel 26 through gears 22, 23 and 24, clutch assembly 30 and shaft 25.Then, the motion of the chain wheel 26 is transmitted to the rear wheel through chain wheels 41, 44 and 46 and chains 42 and 47. The function of the bearing 43 is to cause the crank shaft 45 to move simultane ously with the chain wheel 41 when the chain wheel 41- rotates clockwise, and to prevent the shaft 45 from being driven by the chain wheel 41 when one's feet depress the pedals.

It can be appreciated that the clutch cable 37 which is connected to the cone member 33 extends to the handle of the moped in the same way as the conventional clutch cable.

When the clutch cable 37 is operated in the manner as used in the conventional moped or bicycle, it pulls the cone member 33 backward against the biassing force of the spring 34, thereby causing the shoes 312 and the lining blocks 32 to contract by the force of the looped springs 325. In this situation, the shaft 25 does not move with gear member 24, and one can operate the pedals to rotate the shaft 25.

With the invention thus explained, it is apparent that various modifications and variations can be made without departing from the scope of the invention. It is intended that the invention be limited as indicated in the ap

Claims

pended claims. CLAIMS

1. A moped having a frame, a front wheel and a rear wheel attached to the frame, and a drive mechanism mounted to the intermediate portion of the frame, wherein said drive mechanism is characterized by: a power means, a cylindrical housing mounted adjacent to said power means, a first gear member having a toothed annular portion of larger diameter and a hollow cylindrical body portion of smaller diameter provided in said housing, a first bearing member provided between the inner side of said housing and the periphery of said hollow cylindrical body portion for mounting said first gear member in a rotatable position, a second gear member for transmitting the output motion of said power means to said first gear member, a shaft member mounted in said toothed annular portion in a position rotatable relative to said annular portion, a chain transmission means for transmitting the motion of said first gear member to said rear wheel, said chain transmission means including a chain wheel mounted on said shaft member, and a clutch assembly which includes a truncated cone-shaped member provided in said hollow portion in a coaxial position and connected to said shaft for simultaneous rotation, said cone member having having spaced apart axial ribs on its periphery, shoe members of segmented annulusshaped cross-section surrounding said cone member and spaced by said ribs, shoe lining blocks of segmented annulus-shaped crosssection provided around said shoe members and in contact with the inner side of said hollow portion, an extension spring biassing said cone member to move in a first direction which causes said shoe members and said lining blocks to expand radially so as to place said clutch assembly in an engaged position, a clutch cable connected to said cone member so as to pull it in a second direction opposite to said first direction, and a looped spring member incorporated with said lining blocks for contracting said lining blocks and said shoe members when said cone member is pulled by said clutch cable.

2. A moped as claimed in Claim 1, wherein said clutch assembly further includes an adjusting nut to adjust the tension of said tension spring.

3. A moped substantially as described hereinbefore with reference to the accompanying drawings.

4. A drive mechanism for a moped having a frame, a front wheel and a rear wheel attached to the frame, wherein the drive mechanism is adapted to be mounted on an intermediate portion of the frame and comprises a power means, a cylindrical housing mounted adjacent to said power means, a first gear member having a toothed annular portion of larger diameter and a hollow cylindrical body portion of smaller diameter provided in said housing, a first bearing member provided between the inner side of said housing and the periphery of said hollow cylindrical body portion for mounting said first gear member in a rotatable position, a second gear member for transmitting the output motion of said power means to said first gear member, a shaft member mounted in said toothed annular portion in a position rotatable relative to said annular portion, a chain transmission means for transmitting the motion of said first gear member to said rear wheel, said chain transmission means including a chain wheel mounted on said shaft member, and a clutch assembly which includes a truncated coneshaped member provided in said hollow portion in a coaxial position and connected to said shaft for simultaneous rotation, said cone member having spaced apart axial ribs on its periphery, shoe members of segmented annulus-shaped cross-section surrounding said cone member and spaced by said ribs, shoe lining blocks of segmented annulus-shaped cross-section provided around said shoe members and in contact with the inner side of said hollow portion, an extension spring biassing said cone member to move in a first direction which causes said shoe members and said lining blocks to expand radially so as to place said clutch assembly in an engaged position, a clutch cable connected to said cone member so as to pull it in a second direction opposite to said first direction, and a looped spring member incorporated with said lining blocks for contracting said lining blocks and said shoe members when said cone member is pulled by said clutch cable.

5. A drive mechanism substantially as described herein with reference to the accompanying drawings.