"Stud"

Field of the Invention

The present invention relates to a stud. More particularly, the stud of the present invention is intended for use with the spoked-wheel rims of bicycles and the like.

Background Art

Historically, spoked-wheel rims for bicycles and the like have required a barrier to protect the inner tube of the tyre from being scuffed or punctured by spoke nipple heads, and particularly by protruding threaded spoke ends. The barrier typically employed is known as "rim tape". Such rim tape was originally a cotton tape, but has progressed though rubber strips to synthetic materials also.

The introduction of hollow bicycle rims have recessed spoke nipples still requires use of a rim tape. This is due to the need to provide access holes in the peripheral or outer surface of the rim, the portion of the rim contacting the inner tube of the tyre, as otherwise the inflated inner tube can extend into the access holes that have been drilled in the peripheral surface of the rim and may be scuffed or cut on the sharp edges thereof.

The rim tape that is used to cover the access holes can be required to withstand pressures of up to 10 bar. Not surprisingly, most (if not all) rim tapes "cup" to varying extents under such pressure, some actually yielding due to material failure or as a result of their being cut by the shape edges of the drilled access holes.

In addition, if it is necessary to access a spoke nipple, the entire adhesive-backed and expensive rim tape needs to be removed from the rim. Once removed, the rim tape is typically discarded. The removed rim tape may be reapplied, but does not generally locate well and loses some of its support properties, thereby increasing the chance of its failure and a blowout.

International Patent Application PCT/AU02/01332 (WO 03/026905) discloses a stopper that is characterized by a bearing member and a base member. The base member projects from a lower or bottom surface of the bearing member and is proportioned to be received within a spoke access hole of the wheel rim. The base

member includes a neck portion and an outermost end at which an annular rim is provided. Unfortunately, the design disclosed in this prior art document has been found not to result in sufficiently positive location of the stopper in the spoke access hole. This is believed to be a direct consequence of the design of the base member and the annular rim. This design allows significant "play" between the base member and the spoke access hole, allowing the bearing member to lift from the wall of the rim and thereby snag the inner tube there between.

The design of the stopper of International Patent Application PCT/AU02/01332, with regard to the segmented nature of the base member, is difficult to mould, requires significant hold-time in the die and leads to significant waste of materials. Further, in the moulding process this prior art design requires that the waste material be sorted from the stopper product, thereby increasing the time taken in manufacture.

The present invention has one object thereof to substantially overcome the abovementioned problems associated with the prior art, or to at least provide a useful alternative thereto.

The preceding discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia as at the priority date of the application.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", 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.

Disclosure of the Invention

In accordance with the present invention there is provided a stud comprising a bearing member and a base member, the base member projecting from a lower surface of the bearing member, the base member being proportioned to be received and retained within a spoke access hole of the wheel rim such that an inner tube can not press or blow through that spoke access hole, the base member characterised

by having provided either at or on an outer surface thereof a plurality of radially projecting engaging ridges proportioned so as to provide an interference fit between the base member and the spoke access hole.

Preferably, the plurality of engaging ridges extend from adjacent the bearing member along a substantial proportion of the outer surface of the base member.

More preferably, the engaging ridges are spaced equi-distant apart about the outer surface of the base member.

The engaging ridges are preferably provided in at least two profiles and include a profile that presents a sharp ridge radially and a profile that presents an arcuate or smooth face radially.

In one form of the present invention the engaging ridges of sharp and smooth faces are spaced equi-distant about the outer surface of the base member in an alternating fashion.

Preferably, an outermost end of the base member that is spaced apart from the bearing member is chamfered to facilitate location in, and pushing through, the spoke access hole. Further, the engaging ridges of the outer surface of the base member are similarly chamfered.

The base member is preferably proportioned such that the circumference of the outer surface of the base member matches the smallest diameter of the spoke access holes of the wheel rim to which such may be fitted. The sharp faced engaging ridges preferably extend some way beyond the outer surface of the base member to an extent that generally matches the largest variable size of the spoke access holes of the wheel rim to which such may be fitted.

Still preferably, the smooth faced engagement ridges are provided so as to extend only part way between the outer surface of the base member and the sharp faced engagement ridges thereof.

Preferably, the stud of the present invention is of a design that facilitates a minimal hold-time in a die used to mould same.

The base member is preferably formed of a material that confers flexible resilience thereto, thereby allowing some level of deformity and/or shearing of the engaging ridges during fitting into the spoke access hole.

Brief Description of the Drawings

The stud of the present invention will now be described, by way of example only, with reference to one embodiment thereof and the accompanying drawings, in which:-

Figure 1 is a cross-sectional side view of a stud in accordance with the present invention;

Figure 2 is a bottom plan view of the stud of Figure 1 , showing the arrangement of sharp and smooth engaging ridges provided thereon;

Figure 3 is an upper perspective view of the stud of Figure 1 ; and

Figure 4 is a lower perspective view of the stud of Figure 1.

Best Mode(s) for Carrying Out the Invention

In Figures 1 to 4 there is shown a stud 10 comprising a bearing member 12 and a base member 14. The base member 14 projects from a lower surface 16 of the bearing member 12.

The bearing member 12 is of substantially elliptical form in plan view, describing a longitudinal axis X-X. The bearing member 12 is curved upwardly and outwardly along the X-X axis, as can be seen with reference to Figures 1 , 3 and 4 or is what may be described as "hollowed-out" or bowed along that axis. A peripheral edge 18 of an upper surface 19 of the bearing member 12 is chamfered.

The base member 14 is substantially hollow cylinder in form and projects from the lower surface 16 of the bearing member 12 in a generally central location. The base member 14 comprises a neck portion 20 and an outermost end 22, the outermost end 22 being chamfered. The chamfer facilitates location of the base member 14 in, and its passage through, a spoke access hole (not shown) into which it is to be fitted.

The base member has an outer surface 24 of which are provided a plurality of engaging ridges. The engaging ridges are spaced equidistant about the outer surface 24. The engaging ridges are provided in two forms. The first is a "sharp" engaging ridge 26 and the second, a "smooth" engaging ridge 28. The descriptions "sharp" and "smooth" relate to the profile that each ridge presents radially with respect to the base member 14.

The engaging ridges 26 and 28 are spaced equidistant apart about the outer surface 24 in an alternating fashion, as is best seen in Figure 2.

The base member 14 is proportioned so that the circumference of the outer surface 24 of the base member 14 is marginally smaller than the smallest diameter of the spoke access holes of the wheel rim to which such may be fitted, for example by

0.2 mm. The sharp engaging ridges 26 preferably extend some way beyond the outer surface of the base member 14 to an extent that generally matches the largest variable size of the spoke access holes of the wheel rim to which such are to be fitted. Wheel rims, for example, typically have spoke access holes that are drilled at a diameter of between 8 and 11 mm.

The smooth engaging ridges 28 are provided so as to extend radially only part way between the outer surface of the base member 14 and the sharp engaging ridges 26.

By way of an example, the stud 10 of Figures 1 to 3 has a base member 14 with a diameter of 8.8 mm. The effective diameter of the smooth engaging ridges 28 is 9.2 mm and of the sharp engaging ridges 26, 9.4mm.

As is clear from Figures 1 , 3 and 4, the engaging ridges 26 and 28 are chamfered in a similar manner to the outermost end of the base member 14.

It is envisaged that the base member may comprise a projection from the lower surface of the bearing member in a form other than the hollow cylinder form whilst still supporting or incorporating the engaging ridges at an outer surface thereof. For example, the base member may be provided in the form of a six-pointed star when viewed from below, the points of the star forming/constituting the engaging ridges.

In use, the stud 10 of a suitable size relative to the diameter of the spoke access hole, is fitted into the spoke access hole by a user positioning the base member 14

above the spoke access hole and pushing downwardly on the bearing member 12, so as to push the base member 14 through the spoke hole. In this process the base member 14 and the engaging ridge(s) 26 and/or 28 form an interference fit with the spoke access hole, holding the base member 14 firmly therein. In this process either or both the sharp and/or smooth engaging ridges may be shaved of or worn away to some extent, thereby increasing the effectiveness of the engagement between the base member 14 and the spoke access hole. This in turn minimizes any chance that the bearing member 12 may lift off the wall of the rim in which the spoke access hole is provided and trap or puncture an inner tube as may be the case with prior art studs.

Further contributing to the effectiveness of the engagement between the spoke access hole and the base member 14 is the flexible resilience of the material from which the stud 10 is preferably formed. For example, a polymeric material with a degree of flexible resilience is preferred for this reason. As the base member 14 is pushed into the spoke access hole the base member 14 deforms to some extent, presuming the appropriately sized stud 10 has been chosen, and rebounds once clear of the spoke access hole, thereby effecting a positive engagement of the stud 10 in position in the spoke access hole.

The provision of alternating sharp and smooth engaging ridges, 26 and 28 respectively, about the base member 14 in an equidistant and alternating fashion facilitates the centring of the base member 14 in the spoke access hole.

The hollow nature of the base member 14 allows the head of a spoke tightening screw that may be provided in the head of the spoke to be accommodated. Further, the one piece design of the base member 14 allows for significant savings in terms of moulding time (time in the die) and also in terms of materials, when compared with prior art studs.

Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. For example, whilst one embodiment of the invention is described herein, the skilled addressee will appreciate that aspects thereof may be modified without departing from the spirit and scope of the invention.