GRIFFITH HACK PATENTS, TRADE MARKS, IP LAW SPECIFICATION OF PATENT APPLICATION COUNTRY AUSTRALIA TYPE Patent TITLE Improved end cap for a roller APPLICANT Sandvik Mining and Construction Perth Pty Ltd P77787 AU.1 Pat Set_Filing Application 2009-1-27.doc (S) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Standard Patent Applicant: Sandvik Mining and Construction Perth Pty Ltd Invention Title: Improved end cap for a roller The following statement is a full description of this invention, including the best method for performing it known to me/us: P?7787.AU.1 PatSet_Fding ApplIcation 2009-1-27 doc (S) - 2 IMPROVED END CAP FOR A ROLLER FIELD OF THE INVENTION The present invention relates to improved end caps for s rollers (particularly idler rollers) for use in a conveying system. DISCLOSURE OF THE INVENTION In a first aspect, the present invention provides an end 10 cap for a roller for use in a conveying system. The end cap comprises an axis about which the end cap is rotatable, first and second ends spaced along the axis and an outer radial face. The outer radial face comprises a relief portion into which an end of the roller is 15 deformable to thereby secure the end cap to the roller. The end cap further comprises a passage extending from the first end to the second end. It will be appreciated that it is not necessary to weld, 20 adhere or otherwise bond the end caps described above to a roller in order to secure the end caps to the roller. Simply deforming an end of the roller into the relief portion in the outer radial face of the end cap secures the end cap to the roller. Rollers having the end caps 25 described above are therefore less likely to suffer from joint breakages (thus reducing the risk of damaging a conveyor belt in operation), or heat distortion during formation. The inventors have found that rollers having the end caps described above have low noise 30 characteristics and reduced vibration in use, and are therefore quieter in operation than conventional rollers. The passage between the first and second ends enables fluid communication between the inside and outside of a 35 roller, thus preventing any build up (or drop) in pressure inside the roller. N \Sydney\Cases\Patent\76000-76999\P76455.AU\Specis\P 7 6455.AU Specification 2008-12-16.doc 27/01/09 -3 In some embodiments, the passage is adapted to allow a flow of gas therethrough, but not a flow of a liquid or solid material. 5 In a second aspect, the present invention provides an end cap for a roller for use in a conveying system. The end cap comprises an axis about which the end cap is rotatable, first and second ends spaced along the axis and an outer radial face. The outer radial face comprises a io relief portion into which an end of the roller is deformable to thereby secure the end cap to the roller. The end cap further comprises an inner radial wall which defines a bore for receiving a drive component (e.g. a bearing, with seals if necessary) for enabling the is resultant roller to be rotatably mounted in a conveying system, and a retaining rib on the inner radial wall for retaining the drive component in the bore. Providing a retaining rib integrally formed with the end 20 cap can advantageously provide a simpler, lighter and more secure means for retaining the drive component within the bore of the end cap. In some embodiments, the retaining rib extends radially 25 inwardly from the inner radial wall. In a third aspect, the present invention provides an end cap for a roller for use in a conveying system. The end cap comprises an axis about which the end cap is 30 rotatable, first and second ends spaced along the axis and an outer radial face. The outer radial face comprises a relief portion into which an end of the roller is deformable to thereby secure the end cap to the roller. The end cap further comprises an inner radial wall which 3s defines a bore for receiving a drive component (e.g. a bearing) for enabling the resultant roller to be rotatably mounted in a conveying system, and one or more cavities N:\Sydney\Cases\Patent\7600-76999\P76455.AU\Specis\P76455 AU Specification 2008-12-16.doc 27/01/09 - 4 disposed between the inner wall and the outer radial face. Providing one or more cavities in the end cap can significantly reduce its weight and the amount of material 5 needed to form the end cap, but without compromising the strength of the end cap. Typically, the one or more cavities open to the first end, the first end being arranged in use to be located inside 10 the roller. Such cavities are therefore not exposed to the operating environment and are unlikely to become clogged with material. In some embodiments, a plurality of cavities are angularly 15 spaced apart from one another about the axis of the end cap. The cavities may, for example, be evenly spaced about the end cap axis. Typically, the cavities are separated by radial ribs. 20 Typically, the relief portion comprises a portion of reduced diameter. In some embodiments, the relief portion is tapered inwardly in the direction of the second end, the second end being arranged in use to be located outside the roller. Deforming the end of the roller onto the end 25 cap is therefore achieved simply by crimping the end of the roller into the relief portion. In a fourth aspect, the present invention provides a roller for use as an idler roller in a conveying system 30 comprising a tubular body enclosed at each end with an end cap of the first, second or third aspect of the present invention. N:\Sydney\Cases\Patent\76O0-76999\P76455.ALSpecis\P76455.AU Specification 2008-12-16.doc 27/01/09 - 5 BRIEF DESCRIPTION OF THE DRAWINGS A specific embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 5 Figure 1 shows a perspective view of an end cap in accordance with a preferred embodiment of the invention; and 10 Figure 2 shows a cross-sectional side elevation through the diameter of the end cap of Figure 1. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENT Referring firstly to Figure 2, a portion of a tubular body 15 1 capped at one of its ends by an end cap 2 is shown. The end cap 2 is formed with an internal bore 3 which is configured and dimensioned to accommodate the seals and bearings which serve to provide a sealing support for the resultant roller upon a shaft (not shown). 20 The end cap 2 has an outer radial face 4 which is formed with a relief portion 5 at the region proximate the outer face of the end cap 2. The relief portion 5 is provided at an intermediate position along the outer radial face 4. 25 The radial face 4 is terminated at its outer extent by an annular rib 6. The relief portion 5 is formed with a taper such that it is of a diameter which is less than that of the outer radial face 4 of the main body of the end cap 2, while the rib 6 serves to provide a termination 30 for that taper. In assembly of a roller, the tubular body 1 is formed such that it is of substantially constant cross section throughout its length. The end caps 2 are then applied to 35 the ends of that tubular body 1. In order to retain the end caps 2 in position on the tubular body 1, the outer end portions 7 of the tubular body 1 are swaged or N \Sydney\Cases\Patent\7600-76999\P76455.AU\Specis\P76455AU Specification 2008-12-16.doc 27/01/09 - 6 similarly deformed inwardly into the space defined by the relief portions 5 such that they are caused to lie in close abutting relationship with the outer radial faces 4 of the end caps 2 in the spaces defined by the relief 5 portions 5 and such that the outer edges of the tubular body 1 abut against the axial innermost face of the ribs 6. Once the outer end portions 7 of the tubular body 1 have been deformed such that they are in close abutting relationship with the relief portions 5, the end caps 2 10 are positively retained in position in the tubular body 1. In an alternate embodiment (not shown) the relief portion may have a diameter which need not be less than that of the outer radial face of the main body of the end cap 2, is but instead be formed by a portion which is integral with the main body of the end cap but which is formed of a material which is of a reduced rigidity or, alternatively, is more compressible and is therefore more easily compressed with deformation of the end portion 7 of the 20 roller 1. The outer face of the bore 3 can be formed with a protrusion 8, which extends radially around the outer periphery of the bore 3. In use, the protrusion acts to 25 securely retain the drive components (e.g. a bearing, labyrinth seal and shaft) for the roller within the bore. Referring now to Figure 1, an alternate view of end cap 2 is shown in which a hole 9 can be seen extending from the 30 outer face to the inner face of the end cap 2. The hole 9 enables the inside of the roller to be in fluid communication with the atmosphere so that it is not possible for heating or cooling of the roller during use to cause a pressure build up or drop inside the roller. 35 Typically, the hole is small enough to allow a flow of gas therethrough, but not a flow of liquid or solid material N \Sydney\Cases\Patent\760O0-76999\P76455.AU\Specis\P 7 64 55 .AU Specification 2008-12-16.doc 27/01/09 -7 so as to not contaminate the inside of the roller. Alternatively, the hole may comprise a valve arrangement to prevent solid or liquid contaminants getting inside the roller. 5 As can also be seen in Figure 1, end cap 2 also has a number of cavities 10 which extend from the rear face towards the front face of the end cap 2. The cavities 10 are spaced evenly around the central axis of the bore 3 of 10 the end cap 2 and are separated by ribs 11. End caps having such cavities have a similar strength to end caps not having cavities, but require less material to form and weigh significantly less. 15 In use, the end cap 2 would usually be orientated with respect to tubular body 1 such that the cavities 10 are located inside of the resultant roller. 20 The end caps described herein may be formed from any suitable material, taking into account the material's heat generation, expansion, corrosion resistance, strength and weight characteristics. As it is not necessary to weld the end caps described herein to the rollers, the end caps 25 do not need to be metallic. Indeed, in preferred embodiments, the end caps are formed from non-metallic materials so that they are highly resistant to corrosion and weathering. 30 Preferably, the end caps of the invention are made from a composite material, such as glass filled nylon. Composite materials have been found to provide end caps having excellent strength and dimensional stability, and are relatively cheap materials. 35 When considering the material to be used in forming the end caps, the conveyor system the end caps are to be used N:\Sydney\Cases\Patent\7600-76999\P76455 AU\Specis\P76455 AUSpecification 2008-12-16.doc 27/01109 - 8 in must be considered. For example, end caps used in underground coal conveyor systems must be fire resistant and anti-static (FRAS) in order to comply with government standards. End caps used above ground or below ground in s hard rock applications (e.g. nickel or gold mining) should be UV and ozone resistant. Typically, end caps of the invention are formed by an injection moulding process where heated material (e.g. 10 glass filled nylon) is injected into a dye, allowed to cool and then ejected onto a suitable collection point. It should be appreciated that the scope of the present invention need not be limited to the particular scope of 15 the embodiment described above. For example, it will be appreciated that end caps having hole 9, but not cavities 10 and/or protrusion 8 fall within the scope of the present invention. 20 In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, 25 i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. N \Sydney\Cases\Patent\76000-76999\P76455.AU\Specis\P 76 455.AU Specification 2008-12-16.doc 27/01/09