The present application claim priority from:
The present disclosure relates to the rim of a wheel, and to a wheel comprising such a rim. In a particular form the present disclosure relates to the profile of a rim when viewed from the side, for a wheel of a bicycle, motorcycle, wheelchair, other wheeled vehicle, or any other function for a wheel. The present invention is applicable to a wheel that has spokes numbering from 2 to 9, in singles or pairs, wherein the spokes are designed to supply support under both compression and tension.
A conventional wheel consists of a rim to support a tyre, a hub to support bearings connecting the wheel to the axle of the vehicle, and spokes to join the rim to the hub. The spokes may be flexible and function only under tension as is common on a bicycle wheel that commonly features 16-36 spokes, or the spokes may be rigid and function under both compression and tension as is common on street motorcycle and cars wheels.
Where a high strength to weight ratio is desirable, designers must consider many aspects of the wheel design. The rim must adequately support the tyre under forces of acceleration, braking, lateral forces from cornering, and impact forces from bumps. The spokes must effectively transfer these forces, and the weight of the vehicle and its driver/rider between the rim and the hub. The hub must be adequately strong and well designed to support the spokes and provide an efficient connection between the wheel and the bearings that rotably connect to the vehicle at the axle or mounting point. Other desirable properties of a well-designed wheel may include favourable aerodynamics, stiffness or flex, and affordable cost of manufacture.
A high strength to weight ratio enables a lighter wheel and is favourable for its positive effect on acceleration and braking performance. It also reduces the unsprung mass. Reducing unsprung mass has a positive impact on performance, handling, and comfort over bumpy terrain. Because the wheel is rotating, it is subject to gyroscopic forces that magnify the felt effect of the wheels mass as the rotation speed increases. It thus becomes highly advantageous to the handling and performance of the bicycle, motorcycle, or other wheeled vehicle, to reduce the wheels mass where possible.
It is against this background and the problems and difficulties associated therewith that the present invention has been developed.
Certain objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.
According to a first aspect of the present invention, there is provided a rim for a wheel. The wheel comprising a rim, spokes, and hub wherein the spokes rigidly connect the rim to the hub. The spokes further provide support under forces of compression and tension. The rim depth varies wherein the section approximately half way between spoke connection points to the rim is of the greatest depth. Further, the section of rim located between the spoke connection point to the rim and the centre-point of the rim between spokes is of the shallowest depth.
In one form, the depth of the rim is deepest at a location approximately half way between the spoke connection points to the rim
In one form, the depth of the rim is shallowest approximately mid-point between the spoke connection point to the rim and the centre-point of the rim between spokes
In one form the spokes rigidly connect the rim to the hub and provide support under forces of both compression and tension
In one form the spokes number from 2 to 9.
In one form the spokes number from 2 to 9 pairs.
According to a further aspect there is provided a wheel comprising a rim of varying depth. The rim depth varies wherein the section approximately half way between spoke connection points to the rim is of the greatest depth. Further, the section of rim located between the spoke connection point to the rim and the centre-point of the rim between spokes is of the shallowest depth. The wheel further comprising spokes that function under both tension and compression rigidly connecting the rim to the hub. The wheel further comprising a hub to connect the wheel to a non-rotating axle or mounting point of a vehicle.
For ease of description, wheels embodying the various aspect of the present invention are described below in their usual assembled position as shown in the accompanying drawings and terms such as front, rear, upper, lower, horizontal, longitudinal etc., may be used with reference to this usual position. However, the wheels may be manufactured, transported, sold, or used in orientations other than that described and shown here.
A detailed description of one or more embodiments of the invention is provided below along with accompanying Figures that illustrate by way of example the principles of the invention. While the invention is described in connection with such embodiments, it should be understood that the invention is not limited to any embodiment. On the contrary, the scope of the invention is limited only by the appended claims and the invention encompasses numerous alternatives, modifications and equivalents. For the purpose of example, numerous specific details are set forth in the following description in order to provide a thorough understanding of the present invention.
The present invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the present invention is not unnecessarily obscured.
Embodiments of the present invention will be discussed with reference to the accompanying drawings wherein:
In the following description, like reference characters designate like or corresponding parts throughout the Figures.
A conventional wheel for a bicycle or such includes a rim to support the tyre, a hub to connect the wheel rotably to the axle or mounting point of the fork/frame/or vehicle, and spokes to connect the rim to the hub. A first kind of wheel uses thin spokes to connect the rim to the hub. Spokes usually number 16 or more per wheel. The spokes are pre-tensioned, meaning that even when the wheel is not supporting any weight, the spokes are under tension. The spokes are commonly made from steel but may also be made from Titanium alloy, Aluminium alloy, composites such as carbon/epoxy, or any other material including high strength fibres. These thin spokes function under tension but provide negligible support under compression. A second kind of wheel uses spokes that provide support under tension and compression. Such spokes feature a larger diameter cross-section, and commonly number from 2 to 9 per wheel, and regularly occur in pairs ranging from 2 to 9. These spokes are often made from plastic, magnesium alloy, aluminium alloy, or composites including carbon fibre. The rim, spokes, and part of the hub can often be made in one piece and cannot be disassembled.
For the purpose of this specification, the term “rim” should be construed as being inclusive of any member whose primary function is to support the tyre and provide adequate strength to support the tyre
For the purpose of this specification, the term “hub” should be construed as being inclusive of any member whose primary function is to connect the rotatable wheel to an axle of, or mounting point of the bike or vehicle which is not rotating.
For the purpose of this specification, the term “spoke” or “spokes” should be construed as being inclusive of any member whose primary function is to connect the rim to the hub.
For the purpose of this specification, the term “depth of rim” should be construed as being the measurement from the outer diameter of the rim to the inner diameter of the rim at a cross-section viewed perpendicular to the outer diameter of the rim.
Referring now to
The rim 10 of the wheel 50 includes a midsection 17 that is deeper in its cross-section than area 19 where the spoke 20 connects, and is deeper than area 18 located between the midsection 17 and the spoke connection area 19. The spoke connection area 19 is shallower in its cross-section than the midsection 17 but deeper in its cross-section than area 18. The area 18 is shallower in its cross-section with respect to area 17 and 19.
It is to be noted that for the embodiments shown in
The profile of the rim 10 of the wheel 50 of
Referring now to
The rim 10 of the wheel 50 includes a midsection 17 that is deeper in its cross-section than area 18. The designed depth of the rim 10 at area 19 where the spoke 20 connects to the rim 10 is visibly obscured by the profile of the connection 21 of the spokes 20 to the rim 10. Area 18 of the rim is shallower in its cross-section with respect to any other area of the rim 10.
Referring now to
The benefits of the invention can be understood from two known observations of beam bending theory in physics.
Referring now to
Referring now to
When the above physical phenomena are combined and observed in combination with the circular profile of a rim (acting as the beam) and the spokes (acting as the supports and clamps), the rim profile 10 of the invention herein described emerges as the optimum design for strength-to-weight properties and consistencies in flex.
Throughout the specification and the claims that follow, unless the context requires otherwise, the words “comprise” and “include” and variations such as “comprising” and “including” will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.
It will be appreciated by those skilled in the art that the invention is not restricted in its use to the particular application described. Neither is the present invention restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.
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