GB2359285A

GB2359285A - Drive apparatus for self-propelled velocipede

Info

Publication number: GB2359285A
Application number: GB0003628A
Authority: GB
Inventors: Edward Allen
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-02-16
Filing date: 2000-02-16
Publication date: 2001-08-22
Anticipated expiration: 2020-02-16
Also published as: GB0003628D0; GB2359285B

Abstract

The apparatus (2) comprises a toothed drive device (4), for driving a chain (8), rotatable on first mounting means (10) a pair of pedal levers (12, 14) mounted on either side of the device (4) for reciprocatory motion, each having a first connecting arm (24) and a second connecting arm (28) and which are each connected to the lever mounting means (16), each pair of first and the second connecting arms (24, 28) being connected together by a crank pivot (30), and the drive apparatus (2) being such that each lever is able to cause up to 270{ of circular motion on its crank pivots (30).

Description

1 2359285 DRIVE APPARATUS FOR SELF-PROPELLED VELOCIPED This invention

relates to drive apparatus for a selfpropelled velociped.

Self-propelled velocipeds such for example as bicycles and mountain bikes are well known. The bicycles and mountain bikes generally have two pedal cranks which are rotated by legs of a rider. Each crank is forced downwardly by a leg of the rider in turn. This gives a poor 1800 of power motion. In particular, when one crank is at top dead centre, the other crank is at bottom dead centre at the same time. This tends to give an erratic motion which is most noticeable when a cyclist is negotiating a steep incline.

It is an aim of the present invention to obviate or reduce the above mentioned problem.

Accordingly, in one non-limiting embodiment of the present invention there is provided drive apparatus for a self-propelled velociped, which drive apparatus comprises a drive device which has teeth and which is for driving a chain, first mounting means for the drive device and on which the drive device rotates, a pair of pedal levers arranged one on either side. of the drive device, second mounting means for the pedal levers and about which the pedal levers are caused to move to and f ro during use, a pair of pedals which are positioned one on an end of each pedal lever, a pair of first connecting arms which are one 2 for each pedal lever and which are each connected to their respective pedal lever, and a pair of second connecting arms which are one for each pedal lever and which are each connected to the mounting means, the first and the second connecting arms being connected together by a pair of crank pivots, and the drive apparatus being such that each pedal is able to cause up to 2700 of circular motion on its crank pivot.

The drive apparatus of the present invention is advantageous in that the available 2700 circular motion on each crank pivot gives a large overlap of power motion at top dead centre and bottom dead centre of the pedal levers. This in turn creates a power motion which is much more constantly uniform than that achieved with pedal cranks on known velocipeds. The drive apparatus of the present invention may be used on a wide variety of self-propelled velocipeds including bicycles, mountain bikes, tricycles and self-propelled vehicles suitable for various types of disabilities. The pedal levers of the present invention will normally be operated by a person's when the velociped is a bicycle or legs, for example a mountain bike. However, the pedal levers could alternatively be propelled by hand if they were appropriately positioned, for example in cases where a person did not have use of their legs but they had use of their hands for propulsion purposes.

The drive device may be a ring or a disc. Where the drive device is a disc, then the disc may be provided with 3 a plurality of apertures in order to keep weight to a minimum. Other types of drive device may be employed.

The first mounting means may be a tubular bearing. other types of first mounting means may be employed.

The second mounting means may be a tubular bearing which acts as a fulcrum for the pedal levers. Other types of second mounting means may be employed.

The drive apparatus may include the chain.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawings in which:

Figure 1 is a side view, partially in section of drive apparatus for a self-propelled velociped; and Figures 2, 3 and 4 are views similar to Figure 1 and they illustrate the movement of one of the pedal levers and its associated parts of the drive apparatus.

Referring to the drawings, there is shown drive apparatus 2 for a selfpropelled velociped such for example as a bicycle or a mountain bike. The drive apparatus 2 comprises a drive device 4 which has teeth 6 and which is for driving a chain 8. The apparatus 2 also comprises mounting means 10 for the drive device 4 and on which the drive device 4 rotates.

A pair of pedal levers 12, 14 are arranged one on either side of the drive device 4. The pedal levers 12, 14 are mounted on mounting means 16. The pedal levers 12, 14 are caused during use to move to and fro about the mounting 4 means 16. In the case of a bicycle or a mountain bike, the to and fro movement will be up and down as indicated by the movement arrows 18 in Figure 1. In order to operate the pedal levers 12, 14, a pair of pedals 20 is provided. one pedal 20 is mounted on the end of each pedal lever 12, 14 by means of a pivot 22.

The apparatus 2 further comprises a pair of first connecting arms 24. There is one of the first connecting arms 24 for each pedal level 12, 14. The first connecting arms 24 are each rotateably connected by bearings 26 to the pedal levers 12, 14 as shown.

The apparatus 2 still further comprises a pair of second connecting arms 28 which are one for each pedal lever 12, 14 as shown. Also as shown, each second connecting arm 28 is connected to the mounting means 10.

The first and the second connecting arms 24, 28 operate in pairs as will be appreciated from the drawings. The first and the second connecting arms 24, 28 are connected together by a pair of crank pivots 30. There is one crank pivot 30 for each co-operating pair of first and second connecting arms 24, 28.

The drive apparatus 2 is advantageously such that each pedal lever 12, 14 is able to give up to 2700 of circular motion on its respective crank pivot 30. This can be seen from a comparison of Figures 2, 3 and 4. Figure 2 shows the crank lever 12 at top dead centre, Figure 4 shows the crank lever 12 at bottom dead centre, and Figure 3 shows the crank lever 12 at a position between top and bottom dead centres. The pedal levers 12, 14 move up and down as indicated by the movement arrows 18. They move with a rhombic type of motion. Because there is a large overlap of circular motion between the two pedal levers 12, 14 at their top dead centre and bottom dead centre positions, there is a substantially constant and uniform power motion, which is much superior to the erratic power motion that often occurs with known bicycles and mountain bikes where their pedal cranks which are opposite each other at top dead centre and bottom dead centre.

It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawings has been given by way of example only and that modifications may be effected. Thus, for example, the drive apparatus 2 can be used on velocipeds other than bicycles and mountain bikes. The drive apparatus can also be arranged to be operated by a rider's hand instead of by their feet.

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Claims

1. Drive apparatus for a self-propelled velociped, which drive apparatus comprises a drive device which has teeth and which is for driving a chain, first mounting means for the drive device and on which the drive device rotates, a pair of pedal levers arranged one on either side of the drive device, second mounting means for the pedal levers and about which the pedal levers are caused to move to and fro during use, a pair of pedals which are positioned one on an end of each pedal lever, a pair of first connecting arms which are one for each pedal lever and which are each connected to their respective pedal lever, and a pair of second connecting arms which are one for each pedal lever and which are each connected to the mounting means, the first and the second connecting arms being connected together by a pair of crank pivots, and the drive apparatus being such that each pedal is able to cause up to 2700 of circular motion on its crank pivot.

2. Drive apparatus according to claim 1 in which the drive device is a ring or a disc.

3. Drive apparatus according to claim 1 or claim 2 in which the first mounting means is a tubular bearing.

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4. Drive apparatus according to any one of the preceding claims in which the second mounting means is a tubular bearing which acts as a fulcrum for the pedal levers.

5. Drive apparatus according to any one of the preceding claims and including the chain.

6. Drive apparatus for a self -propelled velociped, substantially as herein described with reference to the accompanying drawings.