Bearing Wheels

Abstract

A bearing wheel (50) has a wheel centre (53) and bearings (14, 16) housed in the wheel centre which are adapted to allow the wheel centre to spin about an axle (18) around which the bearings are mounted. There is an outer surface (20) for contacting a frictional surface over which the wheel centre is to spin. Air flow passageways (22) are formed through the wheel centre, and extend between opposite sides of the wheel centre to allow air flow therethrough to dissipate excess heat caused by friction while the wheel is moving on the frictional surface.

Description

FIELD OF THE INVENTION

The present invention relates to improved bearing wheels and, in particular, to bearing wheels that are used on skateboards, roller skates and the like.

In one aspect, the present invention relates to bearing wheels that have improved air flow through the wheel centre for dissipating excess heat caused by friction when the wheels are being used.

In another aspect, the present invention relates to bearing wheels that have improved resistance to heat conduction and expansion of the wheel centre caused by frictional heat generated during use.

Although the background, objects and preferred embodiments of the invention will be hereinafter described with reference to a bearing wheel for use on skateboards, it is to be understood that the invention is not limited thereto but has wider application. For example, the bearing wheels may be used on roller skates and other movable devices, as well as on stationary devices, such as machinery in which bearing wheels are caused to spin about an immovable axis by frictional contact with moving components of the machinery.

It is to be understood that the terminology employed herein is for the purpose of description only and should not be regarded as limiting. For instance, the terms “comprising” or “comprises” are to be understood as meaning “including”, unless otherwise stated.

Also, the term “bearing” is to be understood as including any device, whether or not it is commonly referred to as a bearing, that can tightly receive an axle through a centre hole defined by a stationary inner ring and has an outer ring that can spin around the inner ring by the rolling action of balls, rods or the like that are captured between the inner and outer rings.

BACKGROUND OF THE INVENTION

The bearing wheels used on skateboards often spin for long periods of time at high rotational velocity, and so are affected by heat caused by friction. The frictional heat is generated at the interface of the wheel with the ground. Commonly, that interface is provided by a polyurethane outer surface which heats up very quickly and, because of its intimate contact with the wheel centre, transfers much of that heat to the bearings which are housed in that centre.

Conventional bearing wheels have centres that are made of the same thermoplastic material as is present at the outer surface, and so heat conduction and expansion of the wheel centre caused by frictional heat generated during use occurs very quickly.

There is little or no effective air flow through the wheel centre for dissipating that heat, and so the bearings housed in the centre are subjected to intense heat that often causes at least some liquification of the bearing grease, resulting in the loss of that grease from the bearings and subsequent poor wheel performance and damage.

The tolerance across the bearing diameters in conventional bearing wheels is also not suitably tight to promote longer life of the bearings. Poor tolerance is exacerbated by the heat conduction and expansion that the wheel centre experiences as a result of frictional heat generated at the outer surface of the wheel.

There have been various attempts in the prior art to address these problems, but most of them have proved unsuccessful functionally or structurally.

The present inventor has found that a better approach to addressing these problems is to provide air flow passageways through the wheel centre and to provide a wheel centre or hub made of a less heat conductive and expansive material than that used at the outer surface of the wheel.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to overcome, or at least substantially ameliorate, the aforementioned shortcomings of the prior art.

It is an object of a first aspect of the present invention to provide bearing wheels that have air flow passageways through the wheel centre which improve air flow through the wheel centre for dissipating excess heat caused by friction when the wheels are being used.

It is an object of a second aspect of the present invention to provide bearing wheels that have improved resistance to heat conduction and expansion of the wheel centre caused by frictional heat generated during use.

Accordingly, in a first broad aspect of the present invention, there is provided a bearing wheel, comprising:

(a) a wheel centre,

(b) bearings housed in the wheel centre and adapted to allow the wheel centre to spin about an axle around which the bearings are mounted,

(c) an outer surface for contacting a frictional surface over which the wheel centre is to spin, and

(d) air flow passageways formed through the wheel centre, the air flow passageways extending between opposite sides of the wheel centre to allow air flow therethrough to dissipate excess heat caused by friction while the wheel is moving on the frictional surface.

Preferably, the wheel centre has a main body portion that is offset to one side of the wheel so that one side of the main body portion is substantially in the plane of one side of the outer surface and the other side of the main body portion is recessed from the plane of the other side of the outer surface to define a stepped recess in that other side of the wheel centre.

In a preferred form, the stepped recess has a face at which there are openings to respective passageways.

The stepped recess is useful for generating turbulent air and for allowing that air to be drawn into the passageways through the openings at the face of the stepped recess.

In another preferred form, the wheel centre is made of aluminium.

It is preferred that the outer surface is provided by a polyurethane cap that is secured around the wheel centre.

The passageways are preferably a plurality of spaced apart, cylindrically drilled, holes located annularly between an outer portion of the wheel centre and an inner portion of the wheel centre, the polyurethane cap being secured upon the outer portion, and the bearings being housed in respective cavities formed within the inner portion.

In a second broad aspect of the present invention, there is provided a bearing wheel, comprising:

(a) a wheel centre,

(b) bearings housed in the wheel centre and adapted to allow the wheel centre to spin about an axle around which the bearings are mounted,

(c) an outer surface for contacting a frictional surface over which the wheel centre is to spin, the outer surface being provided by a cap that is secured around the wheel centre, and

wherein the wheel centre is made of a metal to prevent heat conduction and expansion of the wheel centre caused by frictional heat generated while the wheel is moving on the frictional surface.

Preferably, the metal is aluminium.

The aluminium wheel centre is useful for tightening the tolerance across the bearing diameters, so promoting longer life of the bearings.

It is preferred that the bearing wheel includes air flow passageways formed through the wheel centre, the air flow passageways extending between opposite sides of the wheel centre to allow air flow therethrough to dissipate excess heat caused by friction while the wheel is moving on the frictional surface.

Preferably, the wheel centre has a main body portion that is offset to one side of the wheel so that one side of the main body portion is substantially in the plane of one side of the outer surface and the other side of the main body portion is recessed from the plane of the other side of the outer surface to define a stepped recess in that other side of the wheel centre.

In a preferred form, the stepped recess has a face at which there are openings to respective passageways.

The stepped recess is useful for generating turbulent air and for allowing that air to be drawn into the passageways through the openings at the face of the stepped recess.

It is also preferred that the wheel centre in both aspects of the invention has an outer portion upon which the outer surface is secured, the outer portion having a surface profile comprising a projecting circumferential rib having holes therethrough and grooves on opposed sides of the rib, the surface profile enabling the outer surface to form a bonded lock on itself.

There has been thus outlined, rather broadly, the more important features of the first and second aspects of the invention in order that the detailed description thereof that follows may be better understood and put into practical effect, and in order that the present contribution to the art may be better appreciated.

There are additional features of the first and second aspects of the invention that will be described hereinafter. As such, those skilled in the art will appreciate that the conception, upon which the disclosure is based, may be readily utilized as the basis for designing other assemblies and methods for carrying out the objects of the present invention. It is important, therefore, that the broad outline of the first and second aspects of the invention described above be regarded as including such equivalent constructions in so far as they do not depart from the spirit and scope of those aspects of the present invention.

SUMMARY OF THE DRAWINGS

The first and second aspects of the invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the accompanying drawings, in which:

FIG. 1 is a side view of a wheel centre of a bearing wheel according to a first preferred embodiment of the invention,

FIG. 2 is a sectional end view through A-A of the wheel centre shown in FIG. 1,

FIG. 3 is a sectional end view through A-A of the wheel centre of FIG. 1 after the bearings have been removed therefrom, with the bearings shown unsectioned alongside the sectioned wheel centre, and with a cap on it,

FIG. 4 is a similarly sectional end view of the thermoplastic cap that is secured around the wheel centre as shown in FIG. 3,

FIG. 5 is a side view of a wheel centre of a bearing wheel according to a second preferred embodiment of the invention,

FIG. 6 is an end view showing internal detail of the wheel centre of FIG. 5,

FIG. 7 is an isometric view of the wheel centre shown in FIGS. 5 and 6,

FIG. 8 is a mid-sectional end view of the wheel centre of FIGS. 5 and 6 with a ground engaging cap secured therearound to form a bearing wheel,

FIG. 9 is a side view of a wheel centre of a bearing wheel according to a third preferred embodiment of the invention,

FIG. 10 is an end view showing internal detail of the wheel centre of FIG. 9,

FIG. 11 is an isometric view of the wheel centre shown in FIGS. 9 and 10, and

FIG. 12 is a mid-sectional end view of the wheel centre of FIGS. 9 and 10 with a ground engaging cap secured therearound to form a bearing wheel.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference now to the first embodiment of a bearing wheel according to the invention shown in FIGS. 1 to 4, the bearing wheel 10 includes a wheel centre 12, a pair of bearings 14, 16 housed in the wheel centre and adapted to allow the wheel centre to spin about an axle 18 around which the bearings are mounted. The bearing wheel 10 also includes an outer surface 20 for contacting a frictional surface, such as the ground, over which the wheel centre is to roll. There are also air flow passageways 22 formed through the wheel centre. The air flow passageways extend between opposite sides of the wheel centre to allow air flow therethrough to dissipate excess heat caused by friction while the wheel is moving on the frictional surface.

The wheel centre 12 has a main body portion 24 that is offset to one side of the wheel 10 so that one side 26 of the main body portion is substantially in the plane of one side of the outer surface and the other side 27 of the main body portion is recessed from the plane of the other side of the outer surface to define a stepped recess 28 in that other side of the wheel centre.

The stepped recess 28 has a face at which there are openings 30 to respective passageways 22.

The stepped recess 28 is useful for generating turbulent air and for allowing that air to be drawn into the passageways 22 through the openings 30 at the face of the stepped recess. The circumferential side wall of the stepped recess may cause a stalling of the turbulent air that promotes air flow into the passageways 22. This results in optimal bearing performance and extended bearing life.

In this embodiment, the wheel centre is made of aluminium, although other suitable material may be used, such as other metals, non-metals or combinations of metals and non-metals.

The outer surface 20 of the bearing wheel 10 is provided by a polyurethane cap 32 that is secured around or upon the wheel centre 12 by, in this embodiment, a pressure fit. The cap may alternatively be made of any hard plastic or durable elastomeric material suitable for use in the present invention.

The passageways 22, in his embodiment, consist of twelve spaced apart, cylindrically drilled, holes located annularly between an outer portion 34 of the wheel centre 12 and an inner portion 36 of the wheel centre, the polyurethane cap 32 being secured upon the outer portion, and the bearings 14, 16 being housed in respective cavities 38, 40 formed within the inner portion.

Although the preferred metal used to make the wheel centre 12 is aluminium, the wheel centre may be made of any material that prevents heat conduction and expansion of the wheel centre caused by frictional heat generated while the wheel 10 is moving on the frictional surface.

A wheel centre 12 made of aluminium is also useful for tightening the tolerance across the bearing diameters, so also promoting longer life of the bearings 14, 16.

The cavities 38, 40 which house bearings 14, 16, respectively, are formed by any suitable means, and are interconnected by a hole 42 formed axially in the wheel centre and through which the axle 18 of, say, a skateboard truck, is located. The diameter of the cavities 38, 40 may suit standard 608 bearings. The diameter of the hole 42 may be 12 mm to permit clearance on axle and bearing spacers.

In assembling the bearing wheel 10, the polyurethane cap 32 is secured upon the outer portion 34 of the wheel centre 12, and the bearings 14, 16 are mounted into their respective cavities 38, 40. The axle 18 is then inserted through a centre hole defined by an inner ring of one of the mounted bearings, then through the hole 42, and then through a centre hole defined by an inner ring of the other mounted bearing. A commonly used Nyloc™ nut is fitted to prevent separation of the bearing wheel 10 from the axle 18.

With reference now to the second embodiment of a bearing wheel according to the invention shown in FIGS. 5 to 8, the bearing wheel 50 is similar to the bearing wheel 10 except in the way that the cap is secured upon the outer portion of the wheel centre. For ease of reference, like features have been given like numerals. Reference should be made to the above description of the bearing wheel 10 for an understanding of the structure and function of the like features in the bearing wheel 50.

The outer portion 52 of the wheel centre 53 has a projecting annular rib 54 surrounded on both sides by circumferential grooves 56, 58. The rib 54 has a plurality of equally spaced apart holes 60 drilled across it. The surface profile of the outer portion 52 allows the cap 62 to be secured upon it in an improved way. When, say, molten polyurethane is poured into the mould that forms the cap upon the wheel centre during manufacture, the polyurethane flows into the grooves 56, 58 and through the holes 60 to form a bonded lock on itself, thereby ensuring that the cap 62 does not slip off the outer portion 52. The cap 62 is thus securely keyed to the wheel centre 53.

With reference now to the third embodiment of a bearing wheel according to the invention shown in FIGS. 9 to 12, the bearing wheel 70 is similar to the bearing wheels 10 and 50 except that it lacks a stepped recess in one side of the wheel centre, and in the way that the cap is secured upon the outer portion of the wheel centre. For ease of reference, like features have been given like numerals. Reference should be made to the above description of the bearing wheels 10 and 50 for an understanding of the structure and function of the like features in the bearing wheel 70.

The bearing wheel 70 is manufactured to be of smaller width and diameter than the bearing wheels 10 and 50. The bearing wheel 70 lacks a stepped recess in one side of the wheel centre 72. The wheel centre 72 has a main body portion 74 that is symmetrical, and both sides of the main body portion 74 are outermost and present a respective face at which there are openings 76 to respective passageways 77.

Despite the absence of a stepped recess, air is drawn into the passageways 77 through the openings 76 at the outermost faces of the main body portion 74 of the wheel centre 72, resulting in improved bearing performance and longer bearing life.

The outer portion 78 of the wheel centre 72 has a projecting annular rib 80 surrounded on both sides by circumferential shoulders 82, 84, which in turn are surrounded by circumferential grooves 86, 88. The rib 80 has a plurality of equally spaced apart holes 90 drilled across it. The surface profile of the outer portion 78 allows the cap 92 to be secured upon it in an improved way. When, say, molten polyurethane is poured into the mould that forms the cap upon the wheel centre during manufacture, the polyurethane flows into the grooves 86, 88 and through the holes 90 to form a bonded lock on itself, thereby ensuring that the cap 92 does not slip off the outer portion 78. The cap 92 is thus securely keyed to the wheel centre.

It will be readily apparent from the above description of preferred embodiments of bearing wheels that there are various advantages of such assemblies.

An advantage in one aspect of the present invention is that the bearing wheels have improved air flow through the wheel centre for dissipating excess heat caused by friction when the wheels are being used.

An advantage in another aspect of the present invention is that the bearing wheels have improved resistance to heat conduction and expansion of the wheel centre caused by frictional heat generated during use.

Still further advantages of the present invention will be apparent to persons skilled in the art.

It will also be readily apparent to persons skilled in the art that various modifications may be made in details of design and construction of the embodiments of the bearing wheel, and in the steps of the method of manufacturing and assembling the bearing wheel, described above without departing from the scope or ambit of the present invention.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates before the filing date of this patent application.

Claims

1. A bearing wheel, comprising: (a) a wheel centre,(b) bearings housed in the wheel centre and adapted to allow the wheel centre to spin about an axle around which the bearings are mounted,(c) an outer surface for contacting a frictional surface over which the wheel centre is to spin, and(d) air flow passageways formed through the wheel centre, the air flow passageways extending between opposite sides of the wheel centre to allow air flow therethrough to dissipate excess heat caused by friction while the wheel is moving on the frictional surface.

2. The bearing wheel of claim 1 wherein the wheel centre has a main body portion that is offset to one side of the wheel so that one side of the main body portion is substantially in the plane of one side of the outer surface and the other side of the main body portion is recessed from the plane of the other side of the outer surface to define a stepped recess in that other side of the wheel centre.

3. The bearing wheel of claim 2 wherein the stepped recess has a face at which there are openings to respective passageways whereby, in use, the stepped recess generates turbulent air and allows that air to be drawn into the passageways through the openings at the face of the stepped recess.

4. The bearing wheel of claim 1 wherein the wheel centre is made of aluminium.

5. The bearing wheel of claim 1 wherein the outer surface is provided by a polyurethane cap that is secured around the wheel centre.

6. The bearing wheel of claim 3 wherein the passageways are a plurality of spaced apart, cylindrically drilled, holes located annularly between an outer portion of the wheel centre and an inner portion of the wheel centre, a polyurethane cap being secured upon the outer portion, and the bearings being housed in respective cavities formed within the inner portion.

7. A bearing wheel, comprising: (a) a wheel centre,(b) bearings housed in the wheel centre and adapted to allow the wheel centre to spin about an axle around which the bearings are mounted, and(c) an outer surface for contacting a frictional surface over which the wheel centre is to spin, the outer surface being provided by a cap that is secured around the wheel centre, wherein the wheel centre is made of a metal to prevent heat conduction and expansion of the wheel centre caused by frictional heat generated while the wheel is moving on the frictional surface.

8. The bearing wheel of claim 7 wherein the metal is aluminium.

9. The bearing wheel of claim 8 and including air flow passageways formed through the wheel centre, the air flow passageways extending between opposite sides of the wheel centre to allow air flow therethrough to dissipate excess heat caused by friction while the wheel is moving on the frictional surface.

10. The bearing wheel of claim 1 wherein the wheel centre has an outer portion upon which the outer surface is secured, the outer portion having a surface profile comprising a projecting circumferential rib having holes therethrough and grooves on opposed sides of the rib, the surface profile enabling the outer surface to form a bonded lock on itself.