GB2441988A

GB2441988A - Spoked wheel for a bicycle

Info

Publication number: GB2441988A
Application number: GB0618600A
Authority: GB
Inventors: Lloyd Townsend
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-09-21
Filing date: 2006-09-21
Publication date: 2008-03-26
Also published as: GB0618600D0

Abstract

The wheel comprises a rim 10, a hub and spokes 12 extending between the rim and the hub. The rim 10 comprises a radially outwardly facing tyre seating channel 16 and has flanges 20a which project axially from the opposite sides of the rim beyond the base 16a of the tyre seating channel to receive the ends of the spokes with nipples 14. In this way, the points of attachment of the spokes 12 to the opposite sides of the rim 10 are axially spaced by a distance exceeding the width of the channel base 16a. Each flange 20a is a wall of a box section with a second wall 20b joining the channel 16 adjacent a tyre seating bead 16c, the walls having aligned holes such that one provides access for nipples 14 mounted in the other, or the nipples mounted in one and extending through the other.

Description

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SPOKED WHEEL FOR A BICYCLE

Field of the invention

The present invention relates to a spoked wheel for a bicycle.

Background of the invention

Spoked wheels, which consist of a rim with a tyre seating channel, a hub and spokes connecting the hub to the rim have been used not only on bicycles but also on cars and motor cycles. The tyre seating channel is a radially outwards facing trough which may receive a tubeless tyre, a tyre with an inner tube or even a solid tyre. Normally, the ends of the spokes are secured to the rim within the base of the tyre seating channel.

In a motor car, when cornering, forces act on a wheel in a direction to move the hub axially in relation to the wheel rim. To withstand such forces, spokes are used which extend from the one axial side of the hub to the opposite axial side of the rim, the spokes crossing over when viewed in an axial plane. This inclination of the spokes is in addition to their inclination relative to the wheel radii which is required to transmit acceleration and braking forces. Because of the significant width of the tyre seating channel in a car wheel, it is possible to achieve the required axial rigidity of the wheel while still inserting the outer ends of the spokes into the tyre seating channel of the rim in the normal manner.

Bicycles have not hitherto been thought to require special steps to be taken to withstand axial forces on the hub. Even when cornering, the forces acting between the hub and the rim are generally radial because bicycles need to be banked. However, off-road bicycles and bicycles used for stunts can suffer serious damage as a result of axial forces on the hub. For example, if a rider should attempt to land after an air-born manoeuvre with the wheel rim inclined to the vertical, the resulting forces on the wheel can result in its total disintegration.

Unlike car wheels, the rims of bicycle wheels are relatively narrow (typically less than 40 mm) when compared to their radius (typically 450 mm -600 mm), and as a result of this, securing the spokes to the rim in the conventional manner does not afford the required axial strength.

Summary of the invention

With a view to mitigating the foregoing disadvantage, there is provided in accordance with the present invention a wheel for a bicycle comprising a rim, a hub and spokes extending between the rim and the hub, wherein the rim comprises a radially outwardly facing tyre seating channel, characterised by flanges which project axially from the opposite sides of the rim beyond the base of the tyre seating channel to receive the ends of the spokes, whereby the points of attachment of the spokes to the opposite sides of the rim are axially spaced by a distance exceeding the width of the base of the tyre seating channel.

The invention overcomes the problem of the narrowness of the wheel rim by extending the rim axially so as to allow the ends of the spokes to be more widely spaced than the width of the tyre seating channel. The invention also moves the fixing points of the spokes outside the tyre seating area. Aside from enabling the desired axial strength to be achieved by widening the separation of the spokes at the rim, the invention provides the added advantages of avoiding the problems of sealing around the spokes in wheels intended for tubeless tyres and of enabling the wheel to be trued and spokes to be replaced without the need to remove the tyre.

While it would be possible to have a separate ear-like flange for each spoke, it is preferred to provide a single circumferentially continuous flange on each side of the rim for receiving the ends of the spokes, such a construction allowing the wheel rim to be formed by bending an extruded section.

Advantageously, each of the two flanges is formed by a first wall of an enclosed box section projecting from a side of the tyre seating channel.

In a rim of conventional design, it is not unknown for a tyre seating bead to be distorted when landing after an air-born manoeuvre, especially if the tyre is not fully inflated. By joining a second wall of the closed box section to the tyre seating channel adjacent the tyre seating bead, the tyre seating bead can itself be strengthened.

When using a closed box section to receive the spokes, it is desirable to form aligned holes in both the first and the second walls of the box section.

With a rim constructed in this manner, the spokes may be fitted with nipples engaged in holes of the first wall, the holes in the second wall allowing insertion of, and access with a tool to, the nipples. Alternatively, the spokes may be fitted with nipples engaged in holes of the second wall, the ends of the spokes passing through the holes in the first wall.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawing which is a section through a wheel rim of a wheel constructed in accordance with the present invention.

Detailed description of the preferred embodiment

The drawing shows a section through the rim 10 of a wheel of the invention. The rim is formed of a length of an alloy extrusion which is bent into a circle. The cut opposite ends of the extruded length are joined to one another to form a continuous ring, which is then connected to a hub (not shown) by spokes 12. The spokes cross over one another and are secured at their lower ends to radial flanges on the opposite axial ends of the hub.

Spokes generally have one hooked end which is threaded through a hole and a threaded end which is screwed into an adjusting nipple. In the case of the illustrated embodiment is of the invention, it is the ends of the spokes 12 connected to the rim 10 that are threaded and the adjusting nipples 14 are received in eyelets 16 in the wheel rim 10.

The effective length of the spokes 14 is adjusted by tightening the nipples 12 and, during the truing procedure, such adjustment is carried out in sequence to centre the hub in the rim and to set the correct tension in the spokes.

The rim 10 in the illustrated embodiment of the invention has a tyre seating channel 16 formed of a base l6a and two upstanding side walls l6b terminating in tyre seating beads 16c. As will now be described, various additional walls are formed as part of the extrusion outside the tyre seating channel. The function of these additional walls is to provide additional strength to the rim in general and in particular to the tyre seating bead, to provide a convenient method of aligning and the securing the cut ends of the bent extruded length to one another and to provide fixing points for the ends of the spokes 12.

Two tubes 18 are formed at the corners between the base l6a and the side walls 16b of the tyre seating channel 16.

Two box sections 20 are formed on opposite sides of the rim 10. Each box section has a first wall 20a formed with holes in which eyelets 22 are fixed for receiving the adjusting nipples 14 of the spokes 12. A second wall 20b of the box $ section 20 is joined to an upstanding side wall 16b of the tyre seating channel 16 at or near the tyre seating bead 16c, thereby strengthening the latter. The second wall 20b is formed with holes 20c for inserting the nipples 4 into the eyelets 22 and for enabling a tool, such as a spanner, to be used to adjust the nipples 14 when truing the wheel.

Two further box sections 30 are formed beneath the base 16a of the tyre seating channel 16 by means of walls designated 24, 26 and 28. Each of the walls 28 is common to two adjacent box sections 20 and 30, leading from one of the tubes 18 to a junction between one of the walls 24 and one of the walls 20a. A central wall 26 separates the two adjacent box sections 30 and connects the opposite end of each of the walls 24 to the centre of the base l6a of the tyre seating channel 16.

The points at which the rim 10 is secured to the spokes 12 are wider apart than the base 16a of the tyre seating channel 16 and therefore allow for greater axial rigidity of the wheel than can be achieved if the spokes 12 are secured within the base l6a. The tubes 18 and the closed box sections 20 and 30 surrounding the tyre seating channel 16 strengthen the rim considerably and also form at the ends of extrusion which are to be joined to one another, spaces which can receive pins and/or sleeves to align the ends accurately with one another and resist distortion of the rim. Such pins or sleeves may also be fixed, such as by crimping, within the tubes 18 and the box sections 20 and 30 to prevent the ends of the rim from separating after assembly.

Claims

1. A wheel for a bicycle comprising a rim, a hub and spokes extending between the rim and the hub, wherein the rim comprises a radially outwardly facing tyre seating channel, characterised by flanges which project axially from the opposite sides of the rim beyond the base of the tyre seating channel to receive the ends of the spokes, whereby the points of attachment of the spokes to the opposite sides of the rim are axially spaced by a distance exceeding the width of the base of tyre seating channel.

2. A wheel as claimed in claim 1, wherein a single circumferentially continuous flange is formed on each side of the rim for receiving the ends of the spokes.

3. A wheel as claimed in claim 2, wherein each of the two flanges is formed by a first wall of an enclosed box section projecting from a side of the tyre seating channel.

4. A wheel as claimed in claim 3, wherein a second wall of the closed box section joins the tyre seating channel adjacent a tyre seating bead.

5. A wheel as claimed in claim 4, wherein aligned holes are formed in both the first and the second walls of the box section.

6. A wheel as claims in claim 5, wherein the spokes are fitted with nipples engaged in holes of said first wall, the holes in the second wall allowing insertion of and access to said nipples.

7. A wheel as claims in claim 5, wherein the spokes are fitted with nipples engaged in holes of said second wall, the ends of the spokes passing through the holes in the first wall.

8. A wheel constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.