GB2497329A

GB2497329A - Wheel spoke assembly

Info

Publication number: GB2497329A
Application number: GB201121041A
Authority: GB
Inventors: Jonathan Thulbon
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-12-07
Filing date: 2011-12-07
Publication date: 2013-06-12
Also published as: GB201121041D0

Abstract

A wheel for a bicycle with a number of spoke assemblies attaching the wheel rim to the wheel hub. The spoke assemblies have two attachments to the wheel rim and a single attachment to the wheel hub. Each spoke assembly consists of an outer spoke loop and an inner adjustable spoke. The outer spoke loops can be made using an Aramid fibre or Carbon fibre reinforced plastic to save weight. The inner adjustable spokes have a threaded section to enable the truing and tensioning of the wheel. Greater support at the rim is maintained while keeping the attachment to the hub simple due to the 2:1 rim to hub attachment ratio. This also focuses the weight towards the centre of the wheel, keeping the inertia to a minimum and increasing the performance of the whole wheel.

Description

Wheel spoke assembly.

Background

The present invention relates to the attachment of a rim to the hub of a wheel, which is particularly suited for use on bicycle wheels. The urge for an increase in bicycle performance has resulted in technologically advanced, lighter weight components. Bicycle components are constantly being redesigned to make the most of current materials and technologies. A bicycle wheel typically consists of a central hub, connected to an annular rim via a plurality of spokes. A plurality of spoke nipples, typically at the rim end of the spoke, allows the wheel to be trued and tensioned. The spokes are typically metallic and each spoke runs from the hub to the rim. The performance of the wheel is related to its mass and inertia, so keeping the mass close to the centre of the wheel is advantageous. The standard spoke layout with the spoke nipple at the rim end of the spoke adds weight away from the hub, increasing the inertia. Composite spokes can help to reduce the weight of a wheel, these composite spokes will typically have metallic ends bonded in position to assemble and tension the wheel. The bond between the composite and metallic section of such spokes can be a weak point. The number of spokes used to connect the rim to the hub is always a compromise between strength, performance and the support required to the rim. Wheels with fewer spokes can be lighter, but require a stronger/heavier rim to maintain the same overall strength. The additional mass of the rim will increase the inertia of the wheel, and although the complete wheel may be lighter, the higher inertia will make the wheel feel heavier to spin.

There is a need for a wheel which overcomes the above mentioned problems in the prior art. This invention addresses this need as well as other needs, which will be apparent from the following description, the accompanying drawings and the appended claims.

Summary of the Invention

The present invention is directed toa wheel spoke assembly that connects a rim to a hub of said wheel.

According to the present invention, there is provided an assembly for attaching a rim to a hub, comprising: a rim; a plurality of outer spoke loops; a plurality of inner adjustable spokes; preferably a plurality of spoke nuts; and a hub.

This design enables the use of alternative materials with a higher strength to weight ratio for the outer spoke loop such as Aramid fibres or Carbon Fibre Reinforced Plastic. This reduction of mass in the outer section of the wheel also reduces the inertia and therefore increases the performance of the wheel.

A lighter rim may also be used as the weight penalty for using more spokes is reduced. To further reduce the mass close to the circumference of the wheel, the spoke tensioning is achieved via the inner adjustable spoke. This enables the outer spoke material to be continuous, with no joints between metallic and composite sections which cause weight, strength and manufacturing issues.

The ends of the outer spoke loop have integrally moulded restraining features to anchor both ends of the spoke to the rim. The outer spoke attachment to the rim could be achieved using a split eyelet or threaded collet, thus enabling the moulded ends of the outer spoke loop to pass through the spoke hole in the rim and then be restrained from pulling out of the rim once assembled in position.

The inner adjustable spoke is attached to the outer loop spoke through a ferrule that is bonded to the outer spoke loop and guides the inner spoke between the fibers of the outer spoke loop without breaking them. This maintains the strength and continuity of the outer spoke loop fibres and provides a bearing area for the mating part of the inner spoke. The inner spoke has a threaded section allowing the wheel to be trued and tensioned. This threaded section could be at the hub end of the spoke, mating directly with the hub, or preferably with a nut assembled within the hub. Alternatively, the head of the inner spoke could be attached to the hub in a more convention manor, and the adjustment could be achieved at the junction with the outer spoke loop using a nut or spoke nipple.

The number of attachments to the hub is half the number of attachments to the rim. This gives more support to the rim while allowing a less cluttered attachment to the hub. This potentially allows a stiffer, stronger, lighter weight wheel with a lower inertia.

Introduction to drawings

FIG. 1 Wheel assembly.

FIG. 2 Spoke assembly.

FIG. 3 Exploded spoke assembly and attachment features.

FIG. 4 Example of different spoke pattern.

Detailed description of the preferred embodiments

An embodiment of the present invention will now be explained with reference to the drawings.

Figure 1 shows a bicycle wheel 1 comprising a rim 2, a central hub 3 and a plurality of spoke assemblies 4.

Figure 2 shows a single spoke assembly comprising an outer spoke loop 5 and an inner adjustable spoke 6. The two ends 7 of the outer spoke loop 5 connect to the wheel rim and the free end 8 of the inner adjustable spoke 6 connects to the wheel hub.

Each spoke assembly has two attachments to the rim 7 and a single attachment to the hub 8. This has the advantage of allowing the use of light weight rims due to the good support from the spoke assemblies. The weight of the spokes is kept to a minimum as there are a low number of attachments to the hub that can be weight optimised. To reduce the weight of the wheel further, the outer spoke loops 5 can be manufactured from a lightweight material such as Aramid fibre or Carbon fibre reinforced plastic. Composite outer spoke loops are easily manufactured as there are no adjustment or in-line connecting features that need to be bonded in position. All the weight associated with truing and tensioning the wheel such as threaded metallic components are positioned close to the centre of the wheel to keep the inertia of the wheel to a minimum.

The outer spoke loop 5 would preferably be made from a composite material, and could then be easily moulded to produce an aerodynamic cross section to reduce the air resistance of the wheel. The cross sectional area could be increased towards the attachment points 7 & 9 to help the transition of stresses through these areas. The composite spokes could be a mixture of fibres, possibly to blend the strength of Carbon fibres with the toughness of Aramid fibres. The fibre could be aligned in various patterns including unidirectional for strength, woven into a braid for ease of handling, or a combination of layups. Any composite spokes could have an outer coating, braid or heat shrink layer to protect from ultra violet degrading.

The inner adjustable spoke 6 would preferably be made from a metal such as stainless steel, allowing the adjusting thread, head, and any other connecting features to be included.

Figure 3 is an exploded view of the spoke assembly showing possible attachment features. The end of the outer spoke loop 7 could have cones or similar feature moulded as part of the spoke. This outer spoke ioop could then be restrained in the rim by the use of a split collet 10. The end of the outer spoke loop 7 would be passed through the spoke hoe in the rim, the split colletlO would be positioned under the spoke head and this assembly would then be constrained by the spoke hole in the rim. An alternative embodiment could be a threaded collar that is assembled on the outer spoke loop during manufacture. This threaded collar would then be captive on the completed outer spoke loop, and would need a mating thread on the rim to attach the outer spoke loop to the rim.

The inner adjustable spoke 6 could resemble a conventional bolt with the head 11 bearing on the outer spoke loop via a spoke washer or ferrule 12 that could be moulded into the outer spoke loop 5. This ferrule 12 could sit between the fibres of the outer spoke loop 5 and therefore the load path of the outer spoke loop would not be interrupted. The thread end of the inner adjustable spoke 13 could attach to the hub directly or via a captive or barrel nut 14. An alternative embodiment would be the inner adjustable spoke in the form of a conventional spoke with a head on one end, bent through 90 degrees to mate with an axial spoke hole in the wheel hub, and a threaded section on the other end to mate with the outer spoke loop and tensioned using a nut or spoke nipple. A further embodiment would be the inner adjustable spoke in the form of a conventional straight pull spoke with a head on one end to mate with an in line feature on the wheel hub, and a threaded section on the other end to mate with the outer spoke loop and tensioned using a nut or spoke nipple.

Figure 1 shows a possible layout for the front wheel of a bicycle. The wheel uses a symmetrical spoke pattern and uses a rim with 24 spoke holes and a hub with 12 attachment points. Figure4 shows a possible layout for the rear wheel of a bicycle. The spoke attachments on a rear hub of a bicycle can be offset to allow space for the drive cassette. This results in uneven spoke tensions if a symmetrical spoke pattern is used. This problem can be overcome by increasing the number of spokes on the drive side 15 of the rear wheel, therefore making the spoke tensions more equal. Figure 5 shows a rear wheel with an asymmetrical spoke pattern using a rim with 28 spoke holes and a hub with 14 attachment points. The present invention can be built into wheels using any number of spokes and a variety of spoke patterns. These include, but are not limited to, lightweight symmetrical road bike front wheels with a low spoke count and a zero crossover pattern, asymmetric front disc brake wheels for mountain bikes with a higher spoke count and a crossing spoke pattern, symmetrical rear wheel using an internal gear hub gearbox and a crossover spoke pattern, and strong high spoke count asymmetric rear wheels with a crossover pattern.

There are existing designs that aim to save weight by offering a lower number of lightweight spokes, however these designs require a stronger rim to achieve an equivalent wheel strength. Stronger rims generally have a higher weight and therefore result in a lower performance wheel due to the greater inertia. There are also designs for lightweight rims and hubs, but to achieve an equivalent wheel strength, a higher spoke count is required adding weight and complexity. The present invention concentrates on the wheel as a whole, balancing strength with weight while maintaining a low inertia and therefore high performance.

Although the above embodiments have been described in connection with a bicycle wheel, the present invention can be used with any spoke wheel. All of the features mentioned in this patent specification may be combined in any combination (except where any features are mutually exclusive). Each feature discussed in this patent specification may be replaced by an alternative feature serving the same, equivalent or similar purpose. The invention is not restricted to the preferred embodiments discussed above.

The invention extends to any novel feature or combination of features

mentioned in this patent specification.

Claims

<claim-text>Claims 1. A wheel spoke assembly comprising: an outer spoke loop that connects to the wheel rim in two locations, an inner adjustable spoke that connects to the wheel hub in one location.</claim-text> <claim-text>2. an outer spoke loop according to claim 1 wherein the outer spoke is made from a lightweight material such as Aramid fibres or Carbon fibre reinforced plastic or a mixture of materials.</claim-text> <claim-text>3. an outer spoke loop according to claim 1 wherein the outer spoke is made with a more aerodynamic profile.</claim-text> <claim-text>4. an outer spoke loop according to claim 1 wherein the outer spoke is attached to the rim via a split collet.</claim-text> <claim-text>5. an outer spoke loop according to claim 1 wherein the outer spoke is attached to the rim via a threaded collet that may be captive on the outer spoke loop.</claim-text> <claim-text>6. an outer spoke loop according to claim 1 wherein the outer spoke is made from two or more pieces.</claim-text> <claim-text>7. an inner adjustable spoke according to claim 1 wherein the attachment to the hub is via a threaded section of the inner adjustable spoke and a mating thread in the hub.</claim-text> <claim-text>8. an inner adjustable spoke according to claim 1 wherein the attachment to the hub is via a threaded section of the inner adjustable spoke and a mating nut assembled in the hub.</claim-text> <claim-text>9. an inner adjustable spoke according to claim 1 wherein the attachment to the outer spoke loop is via a threaded section of the inner adjustable spoke and a nut or spoke nipple to allow adjustment.</claim-text> <claim-text>1 O.A wheel assembled using spoke assemblies according to claim 1 arranged in any symmetric or asymmetric spoke pattern.</claim-text> <claim-text>11.A wheel assembled using spoke assemblies according to claim 1 using any numberof spokes.</claim-text>