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Title:
A BICYCLE FRAME AND BICYCLE COMPONENTS
Document Type and Number:
WIPO Patent Application WO/1994/026579
Kind Code:
A1
Abstract:
The present invention provides (with reference to figure 1A) a bicycle frame (10, 11, 12) formed as a monocoque and having a generally Z-shaped side elevation. The present invention also provides (with reference to figure 3) a front fork assembly for a bicycle comprising two stays (e.g. 50) having wheel mounting means (e.g. 56) for supporting a wheel between the members, the stays (e.g. 50) being joined at one end, the stays (e.g. 50) both being shaped as aerofoils in cross section each having a rounded leading edge and each having side surfaces which taper rearwardly from the leading edge to intersect to define a knife-edge-like rearward edge. The present invention further provides (with reference to figure 1A) a bicycle frame (10, 11, 12) having a plurality of stays (25, 26) for mounting a wheel to the remainder of the frame (10, 12) wherein the stays (25, 26) are in the form of cantilever arms extending away from the remainder of the frame (10, 11) and wherein the stays (25, 26) flex to allow motion of a wheel relative to the remainder of the frame (10, 12). The present invention additionally provides (with reference to figure 7) a bicycle seat (100, 101) which is adapted to incorporate a detachable container (101) for drinking fluid and the invention also provides a detachable container (101) having connecting means (103, 105) for connecting the container (101) to a bicycle seat (100) to form a rearward exterior of the bicycle seat (100), the container (101) being shaped to continue the contours of the seat (100).

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Inventors:
HILL RICHARD DAVID (GB)
THOMANN RUDY (GB)
Application Number:
PCT/GB1994/001038
Publication Date:
November 24, 1994
Filing Date:
May 16, 1994
Export Citation:
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Assignee:
LOTUS CAR (GB)
HILL RICHARD DAVID (GB)
THOMANN RUDY (GB)
International Classes:
B62K3/02; B62K19/02; B62K19/16; (IPC1-7): B62K3/02; B62K19/02; B62K19/16
Foreign References:
US3233916A1966-02-08
EP0198284A21986-10-22
DE9103867U11991-05-29
Other References:
GLASKIN: "On the chain gang", ENGINEERING. (INCL. MACHINE SHOP MAGAZINE), vol. 232, no. 8, September 1992 (1992-09-01), LONDON GB, pages 13
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Claims:
CLAIMS
1. A bicycle frame formed as a monocoque having a generally Zshaped side elevation.
2. A bicycle frame as claimed in claim 1 wherein the frame comprises a substantially horizontal top portion, a support portion for the rear wheel and a connecting portion connecting the top portion and the support portion and angled to extend forwardly with respect to the top portion, wherein the top portion and the connecting portion of the frame both have an aerofoil shape in horizontal crosssection, both having rounded leading edges and side surfaces which taper rearwardly.
3. A bicycle frame as claimed in claim 1 or cliam 2 having a top portion which in use defines a substantially horizontal top surface.
4. A bicycle frame as claimed in claim 3 wherein the top portion of the frame has an enlarged portion at the front end thereof which encases a bearing means for mounting a front wheel mounting member, the bearing means being encased in the frame such that the front wheel mounting member when mounted to the frame will extend forwardly of the top portion of the frame at an angle to the top portion.
5. A bicycle frame as claimed in any one of the preceding claims having a rear wheel mounting portion which comprises a wishbone arrangement of two rear stays which have mounting means for mounting the rear wheel therebetween.
6. A bicycle frame as claimed in claim 5 wherein each of the two rear wheel stays is split along the length thereof, each stay having a top member and a bottom member, only the bottom member of each stay being connected to the mounting means for mounting the rear wheel.
7. A bicycle frame as claimed in claim 6 wherein a compliant material is provided to act between the top and bottom members of the stays.
8. A bicycle frame as claimed in claim 7 wherein the compliant material is bonded to the top and bottom members of each stay.
9. A front fork assembly for a bicycle comprising two stays having wheel mounting means for supporting a wheel between the members, the stays being joined at one end, the stays both being shaped as aerofoils in crosssection each having a rounded leading edge and each having side surfaces which taper rearwardly from the leading edge thereof to intersect to define a knifeedgelike rearward edge.
10. A front fork assembly as claimed in claim 9 wherein the leading edge of each support member is straight and the rearward edge of each support member is curved.
11. A bicycle having a frame as claimed in any one of claims 1 to 8 and a front fork assembly as claimed in claim 9 or claim 10.
12. A bicycle frame having two stays in a wishbone arrangement for mounting a wheel to the remainder of the frame, the arms being connected at one end to the remainder of the frame and then curving away from each other to end portions which are spaced apart and substantially parallel.
13. A bicycle frame having a plurality of stays for mounting a wheel to the remainder of the frame wherein the stays are in the form of cantilever arms extending away from the remainder of the frame and wherein the stays flex to allow motion of a wheel relative to the remainder of the frame.
14. A bicycle frame as claimed in claim 13 wherein each stay is split along the length thereof whereby each stay comprises an upper and a lower member, the lower member of each stay having mounting means for connecting the wheel to the stay, the two members acting in use as a leaf spring to allow motion of the wheel relative to the remainder of the frame.
15. A bicycle frame as claimed in claim 14 wherein each stay has compliant material positioned between the upper and lower member thereof, the compliant material damping motion mounted wheel relative to the remainder of the frame.
16. A bicycle seat which is adapted to incorporate a detachable container for drinking fluid.
17. A bicycle seat as claimed in Claim 11 wherein the container for drinking fluid forms a rearward extension of the bicycle seat when attached thereto, the container being provided with an exterior surface which continues the contours of the seat.
18. A detachable container for drinking fluid having connecting means for connecting the container to a bicycle seat to form a rearward extension of the bicycle seat, the container being shaped to continue the contours of the seat.
19. A bicycle frame substantially as hereinbefore described with reference to and as shown in the accompanying figures 1, 2, 5 and 6.
20. A front fork assembly for a bicycle substantially as hereinbefore described with reference to and as shown in the accompanying figures 3 and 4.
21. A bicycle seat substantially as hereinbefore described with reference to and as shown in the accompanying figures 7, 8 and 9.
Description:
A BICYCLE FRAME AND BICYCLE COMPONENTS

The present invention relates to a new bicycle frame and to novel components for a bicycle.

The applicants devised a bicycle which was ridden to success in the Olympic Games at Barcelona in 1992. The bicycle had a "monoblade" front fork construction which consisted of a single support member extending down one side of the front wheel. The handlebars for the bicycle were positioned between the monoblade and the frame. The bicycle frame consisted of a carbon fibre monocoque having an aerofoil cross-section. The monocoque had a top surface which curved downwardly in a direction extending backwardly away from the frame front and then curved smoothly upwardly to a vehicle seat support. The rear surface of the frame was formed by a continuous curve starting at the vehicle seat support and curving down to the mounting point for the rear wheel. A recess was provided at the rear of one side surface of the frame to receive the rear wheel. The front surface of the frame was formed as a smooth curve curving downwardly in the direction rearward of the front wheel and forming a parabolic surface ending at a mounting portion of the frame adapted to support the pedal assembly. This mounting portion of the frame was enlarged with respect to the rest of the frame to provide an aerodynamic tear drop shape.

The present invention provides in a first aspect a bicycle frame formed as a monocoque having a generally Z-shaped side elevation.

This configuration of frame has considerable aerodynamic advantages, but has been avoided to date since a triangular support arrangement for the rear wheel has been thought necessary. Preferably the frame comprises a substantially horizontal top

portion, a support portion for the rear wheel and a connecting portion connecting the top portion and the support portion and angled to extend forwardly with respect to the top portion, wherein the top portion and the connecting portion of the frame both have an aerofoil shape in horizontal cross-section, both having rounded leading edges and side surfaces which taper rearwardly. Preferably the top portion in use defines a substantially horizontal top surface. This is aerodynamically advantageous.

Preferably the top portion of the frame has an enlarged portion at the front end thereof which encases a bearing means for mounting a front wheel mounting member, the bearing means being encased in the frame such that the front wheel mounting member when mounted to the frame will extend forwardly of the top portion of the frame at an angle to the top portion. In the bicycle raced at Barcelona the top portion of the frame was angled to the horizontal and the bearing means perpendicular to the frame, as thought advantageous at the time.

Preferably the bicycle frame has a rear wheel mounting portion which comprises a wishbone arrangement of two rear stays which have mounting means for mounting the rear wheel therebetween. These members form the lowest part of the Z-shaped side elevation. Use of such members instead of a single support member allows standard components to be used. Preferably each of the two rear wheel stays is split along the length thereof, each stay having a top member and a bottom member, only the bottom member of each stay being connected to the mounting means for mounting the rear wheel. The stays thus act as leaf springs giving beneficial suspension effects.

Preferably a compliant material is provided to act between the top and bottom members of the stays.

The compliant material provides damping. The material is preferably bonded to the top and bottom members of each stay.

In a second aspect the present invention provides a front fork assembly for a bicycle comprising two stays having wheel mounting means for supporting a wheel between the members, the stays being joined at one end, the stays both being shaped as aerofoils in cross-section each having a rounded leading edge and each having side surfaces which taper rearwardly from the leading edge thereof to intersect to define a knife-edge-like rearward edge. The two stays can each be narrower in width than a monoblade and this has aerodynamic advantages. The use of such stays also allows use of standard bearing components.

Preferably the leading edge of each support member is straight and the rearward edge of each support member is curved. This is aerodynamically beneficial.

The present invention in a third aspect provides a bicycle frame having two stays in a wishbone arrangement for mounting a wheel to the remainder of the frame, the arms being connected at one end to the remainder of the frame and then curving away from each other to end portions which are spaced apart and substantially parallel. This allows the possibility of suspension without requiring a wide central frame portion.

In a fourth aspect the present invention provides a bicycle frame having a plurality of stays for mounting a wheel to the remainder of the frame wherein the stays are in the form of cantilever arms extending away from the remainder of the frame and wherein the stays flex to allow motion of a wheel relative to the remainder of the frame. Thus the bicycle has a suspension of sorts.

Preferably each stay is split along the length thereof whereby each stay comprises an upper and a lower member, the lower member of each stay having mounting means for connecting the wheel to the stay, the two members acting in use as a leaf spring to allow motion of the wheel relative to the remainder of the frame.

Preferably each stay has compliant material positioned between the upper and lower member thereof, the compliant material damping motion mounted wheel relative to the remainder of the frame.

In a fifth aspect the invention provides a bicycle seat wherein the container for drinking fluid forms a rearward extension of the bicycle seat when attached thereto, the container being provided with an exterior surface which continues the contours of the seat.

The present invention in a sixth aspect provides a detachable container for drinking fluid having connecting means for connecting the container to a bicycle seat to form a rearward extension of the bicycle seat, the container being shaped to continue the contours of the seat.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings in which;

Figures 1A, IB, 1C, ID, IE, IF, 1G, 1H and 1J show a bicycle frame according to the present invention and various cross sections of the bicycle frame, the cross-sections being taken along lines clearly indicated in Figure 1A;

Figure 2 is a partial cross-section taken along the line XX in figure 1 in the direction of the arrows shown in figure 1,

Figure 3 shows a front fork assembly according to the present invention in side elevation,

Figure 4 shows a part cross-section/part front elevation view of the fork assembly of figure 3 , the part cross-section taken along line YY of the figure 3,

Figures 5A and 5B show a rear stay assembly of a second embodiment of the invention,

Figures 6A and 6B show a rear stay assembly of a third embodiment of the invention.

Figures 7, 8 and 9 show a bicycle seat and drinking fluid arrangement according to the invention.

Referring to figure 1A of the enclosed drawings, the bicycle frame according to the present invention can be seen to comprise a monocoque frame having a generally Z-shaped side elevation, the frame comprising a top portion 10, a rear wheel mounting portion 11 and a connecting portion 12 extending between the top portion and the rear wheel mounting portion 11. The frame is in the preferred embodiment constructed of a carbon fibre composite.

The top portion 10 of the frame defines a surface 13 which is horizontal. In the specification (including the claims) where references are made to horizontal and vertical members it should be appreciated that those references refer to the orientation of members when the bicycle frame of the invention is fitted with wheels and positioned on a horizontal surface.

At the front of the top portion 10 of the frame there is a bulbous mounting portion 14 which encases a bearing arrangement 15 for receiving a spindle connected to a front fork. The bearing arrangement 15 and the bulbous casing 14 are arranged such that a spindle mounted in the bearing arrangement 15 is mounted inclined to the vertical so that the fork members for mounting the front wheels extend forwardly from the top portion 10 of the frame.

At the rear of the top surface 13 of the top portion 10 of the bicycle frame a seat mounting member

17 is provided which extends upwardly away from the top surface 13 at an angle inclined rearwardly. In manufacture of the frame, the seat mounting member 17 will be produced with a height exceeding requirements and will then be sawn off to the rider's required height.

A sleeve 31 which surrounds the seat mounting member 17 is provided upon which a seat 16 is mounted. The seat 16 is mounted to the sleeve 31 by a joint 32 which allows pivotting of the seat 16 to suit the rider's requirements. The sleeve 15 can be moved relative to the seat mounting member 17 to allow limited adjustment of the height of the seat 16.

The rear surface of the frame is formed from two curved surfaces 18 and 19. The curved surfaces intersect at a point 20. The curvature of the curved surface 19 is designed to match the curvature of a rear wheel when the rear wheel is attached to the frame. A standard braking arrangement 21 is provided at the lowermost portion of the curved surface 18, to brake a rear wheel when attached to the frame.

The front surface 22 of the frame is curved with the curve extending first rearwardly from the front of the top portion 10 of the frame and then in a forward direction towards the lowermost part of the frame.

The connecting portion 12 of the frame connects the top portion 10 to the rear wheel mounting portion 11. At the bottom of the connecting portion 12 there is provides a bulbous tear drop shape frame portion 23 which encases a standard bottom bracket assembly 24 for mounting a shaft attached to the pedals of a bicycle.

The rear wheel mounting portion 11 of the bicycle comprises two stays 25 and 26 in a wishbone arrangement as can be clearly seen in figure 2. The stays 25 and 26 flare outwardly from the centre line

of the frame as they extend rearwardly. Each stay includes a metal hindmost portion for mounting the rear wheel of the bicycle and the metal portions can be seen at 27 and 28 (these are commonly called "drop-outs") . The rear wheel and the gears of the bicycle (seen at 29) are mounted between the stays using the drop-outs 27 and 28.

The drop-outs 27 and 28 used with the frame could have generally vertically extending slots as shown in figure 1 and this would be common in bikes which used the Derallieur gear system which employs a chain tensioner. Alternatively, the drop-outs 27 and 28 could have the horizontally extending slots as common in racing bicycles, where the horizontal movement of the rear wheel relative to the frame must be allowed to permit chain tensioning.

The frame in the portions 10 and 12 is designed to have an aerofoil shape in cross-section; i.e. the frame portions have a horizontal cross-section with a rounded front portion and rearwardly tapering side surfaces. This is indicated by the various cross-sections of figures ID, IF, 1G, 1H.

It can be seen from figure ID that the rear surface 19 of the frame has a curved portion 30 which is designed to match the curvature of the tyre of a wheel mounted to the frame. The thickness of the rear surface 19 is deliberately designed to be slightly smaller than the thickness of the tyre of a wheel mounted to the frame, to ensure continuous uninterrupted airflow across the frame and the rear wheel, the rear wheel typically being a closed disc type wheel to maximise aerodynamic efficiency.

Figure 1J shows a cross-section taken through the bulbous portion 23 of the frame. It can be seen that the bulbous portion 23 is a lot wider than the connecting portion 12 of the frame immediately above

the bulbous portion 23. This has a beneficial aerodynamic effect.

It will be noted that the new design differs from conventional bicycles and also ditfers from the bicycle raced at the Olympic Games in that there is no triangular support structure for mounting a rear wheel. In conventional bicycles with tubular frames two tubular triangles are provided at the rear of the bicycle frame to support the rear wheel. In the bicycle raced at the Barcelona Olympics a single generally triangular webbing portion of the bicycle frame was provided to support the rear wheel.

The rear stay arrangement 11 for mounting the rear wheel allows flexing of the wishbone arms 25 and 26 and thus allows a degree of motion of the rear wheel vertically relative to the remainder of the frame. Thus, some degree of suspension is allowed by the new design.

The applicant envisages improving the suspension features of the frame by using the two designs illustrated in figures 5A, 5B, 6A and 6B. In the figures only the wishbone wheel mounting arrangement 11 of the frame of the bicycle is shown and it should be appreciated that the remainder of the frame will in preferred embodiments of the invention be identical to the frame discussed earlier.

In the embodiment of figures 5A and 5B both of the rear wishbone arms 25 and 26 are split horizontally along their length into two separate portions 25A and 25B and 26A and 26B respectively. The drop-outs 27 and 28 are mounted only to the lower members 26B and 25B of the rear stays. Thus, the member 25A can move relative to member 25B and similarly 26A can move relative to member 26B. Hence, the rear stays 25 and 26 act as leaf springs allowing vertical motion of the rear wheel.

In a further improvement illustrated in figures 6A and 6B rubber or some other compliant material (shown at 70 in Figure 6B) is included between the split members 25A and 25B and also between the split members 26A and 26B. The rubber acts to damp vertical motions of the rear wheel and thus provide damping in the suspension for the rear wheel. The characteristics of the rubber or other material can be varied to provide the suspension characteristics required. Typically, the rubber or other compliant material will be bonded to split members of each wishbone arm.

It is advantageous when laying down fibres in a mould for the frame to lay the carbon fibres for the rear stays with a selected orientation in order that the rear stays when formed have a desired flexural rigidity. Many different orientations can be chosen to achieve a desired flexural rigidity and in practice the desired orientation of fibres will be chosen emperically.

Figure 3 illustrates the new front fork assembly provided by the invention. The front fork assembly consists of two stays which are mounted to a spindle and then mounted in the bearing assembly 15 in the head portion 14 of the bicycle frame previously described.

Only one of the front fork stays 50 is shown in the figures 3 and 4, but it should be appreciated that the other stay is identical. The stay has an aerofoil cross-section, which is clearly shown in figure 3; cross-sections of the fork member 50 are shown at 51, 52, 53, 54 and 55.

The front fork stays in a preferred embodiment are made out of a carbon fibre reinforced composite. There is provided at the bottom of each fork stay a metal drop-out for mounting the front wheel and one

metal drop-out 56 can be seen clearly in figures 3 and 4.

A front braking mechanism 57 is mounted at the top of the fork stays, where they are joined to each other and also to the spindle 58.

The bicycle can use any form of handlebars required by the rider, normal standard drop handlebars, tri-bars or specialised handlebars as used on the bicycle raced in the Barcelona Olympics.

In figure 7 of the application there is shown a standard bicycle seat 100. There is also shown a container 101 adapted to hold fluid for a rider. The container will preferably have a tube (not shown) connected thereto to allow the rider to draw fluid from the container. In a preferred embodiment the container will include a container holding pressurised fluid with a valve installed in a tube connected to the container operable to allow fluid flow to the rider.

The container 101 is designed to fit the vehicle seat 100 as an extension of the seat with the contours of the container 101 following the contours of the seat. The liquid containers currently used are mounted on bicycle frames and disrupt airflow and thus the use of a container attached to a seat improves the overall aerodynamics of a bicycle.

The container 101 is attached to the vehicle seat 100 by a screw 103. Recesses 105 in the container 101 match bars on the underneath of the seat 100. The bar 104 illustrated in figure 7 has screw holes for engagement by screws such as 103.

The seat 100 and container 101 are shown in figure 9 in an assembled state.

It should be appreciated that whilst the novel wishbone arrangements for mounting the rear wheel of the bicycle which are illustrated in figures 2, 5 and

6 are preferably used with the frame illustrated in figure 1, the wishbone arrangement could be used with any bicycle frame.

It should also be appreciated that whilst the novel front fork arrangement illustrated in figures 3 and 4 is preferably used with the frame illustrated in figure 1, the novel front fork arrangement could be used with any bicycle.