AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION for an Innovation Patent Invention title: "RAILING JOINT" Applicant: JAMES ARTHUR FAWKES Associated provisional applications: The following statement is a full description of the invention, including the best method of performing it known to me: 2 "RAILING JOINT" Field of the Invention The present invention relates to a joint used in railing systems, such as those 5 used in the creation of handrails for walkways. Background to the Invention The provision of handrails for platforms and stairways is regulated by Australian Standard AS1657. One of the requirements of the standard is the 10 handrail has a "smooth continuous top surface"; that is, that one can run one's hand along the upper surface without meeting any impediments. One way in which this standard is met is through the use of a 'ball stanchion'. Railings of this nature use tubular sections generally formed from steel. The sections are joined at substantially spherical 'balls', which generally have 15 horizontally aligned apertures arranged to engage with the tubular sections. The upper rail of a handrail is therefore formed by horizontal tubular sections, with balls spaced at regular intervals along the length of the rail. Although ball stanchions meet the relevant standard, their use is still associated with some problems. In a situation where a worker needs to grasp 20 a rail quickly, the presence of a ball stanchion may lessen the worker's ability to grasp the rail. There is also a view that railing formed with ball stanchions can be unsightly. A further concern is that the ball stanchions can use a relatively large amount of steel, adding to the expense of construction. The present innovation seeks to provide an alternative to ball stanchions 25 which overcomes, at least in part, some of the above mentioned problems whilst retaining conformity with the relevant standard. Summary of the Invention According to one aspect of the present invention there is provided a joint for a 30 railing, the joint having a first open end opposed to a second open end, the open ends arranged to receive end portions of tubular rail sections, the joint having a part-cylindrical outer body portion, the outer body portion having a 3 first end portion associated with the first open end, a middle portion, and a second end portion associated with the second open end, the middle portion having a substantially constant radius, and each of the first and second end portions having a radius which reduces from the radius of the middle portion 5 to a smaller radius at the respective open end. According to a second aspect of the present invention there is provided a joint for a railing, the joint having a first open end opposed to a second open end, the open ends arranged to receive end portions of tubular rail sections, the joint having an outer body portion, the outer body portion having a first end 10 portion associated with the first open end, a middle portion, and a second end portion associated with the second open end, the middle portion being generally elongate, and each of the first and second end portions having a radius which reduces from the radius of the middle portion at its respective end to a smaller radius at the respective open end of the joint. 15 Preferably, the reduction in radius is between 40% and 90% of a thickness of the middle portion. Also preferably, the length of each of the first and second end portions is between 5% and 15% of the length of the length of the middle portion. The first and second end portions may each form a curve, when viewed from 20 the side, the curve including a circular arc, the radius of the arc being greater than the radius of the middle portion. The curve may include an additional circular arc near the respective open end, the additional circular arc having a radius in the order of 1-5% of the radius of the first circular arc. The joint may include screw apertures associated with each of the first and 25 second open ends, the screw apertures arranged to receive grub screws in order hold the end portions of tubular rail sections in position. The joint may include a thickened region about each screw aperture. In a preferred embodiment of the present invention, the screw apertures are located on an under side of the joint. 30 The joint may be generally T-shaped, with a third open end associated with a lower body portion, the lower body portion being substantially perpendicular to the middle portion of the outer body portion and extending beneath the lower body portion. The third open end may be associated with a third end portion of 4 reducing radius. In a preferred embodiment, however, the lower body portion is substantially cylindrical near the third open end. Brief Description of the Drawings 5 It will be convenient to further describe the invention with reference to preferred embodiments of the railing joint of the present invention. Other embodiments are possible, and consequently the particularity of the following discussion is not to be understood as superseding the generality of the preceding description of the invention. In the drawings: 10 Figure 1 is a perspective of a railing joint in accordance with the present invention; Figure 2 is a cross sectional side view of the railing joint of Figure 1; and Figure 3 is a cross sectional end view of the railing joint of Figure 1. 15 Detailed Description of Preferred Embodiments The figures show a T-shaped railing joint 10 for connecting railing sections (not shown) at the top of a handrail. The railing joint 10 shown and described is used for connecting a vertical section to two horizontal sections. It will be appreciated that other styles of connectors can also embody the present 20 invention, and the invention claimed is not limited to T-shaped connectors. The railing joint 10 has a substantially cylindrical upper body portion 12, which is oriented in a generally horizontal direction, and a substantially cylindrical lower body portion 14, which is oriented in a generally vertical direction. The upper body portion 12 and lower body portion 14 are joined in a well known 25 fashion to make the T-shape of the railing joint 10. A cylindrical bore 16 passes axially through the upper body portion 12. The upper body portion 12 thus has a first open end 18 opposed to a second open end 20. The bore 16, and the open ends 18, 20, are sized to receive railing sections within. In the embodiment shown, the bore 16 has an internal 30 diameter of 50mm. The upper body portion 12 has an outer body portion 22, which extends from the first open end 18 to the second open end 20. The outer body portion 22 5 has three sections: a first end portion 24, a middle portion 26, and a second end portion 28. In the embodiment of the drawings, the middle portion 26 is part-cylindrical in shape, with a constant external radius of 60mm. The thickness of the middle 5 portion 26, being the difference between the external radius of the middle portion 26 and the internal radius of the bore 16, is therefore about 5mm. The middle portion 26 represents over 80% of the length of the outer body portion 22. In the embodiment shown, the middle portion has a length of about 112mm, with the outer body portion having a total length of about 135mm. 10 Each of the first end portion 24 and second end portion 28 thus represent a length of less than 10% of the length of the outer body portion. In the drawings, this length is about 11.5mm. It is considered that, in general, lengths between about 5% and about 15% of that of the outer body portion 22 will be suitable for the end portions 24, 28. 15 Each of the end portions 24, 28 reduces in radius towards its associated open end 18, 20. In the embodiment of the drawings, this is achieved by the end portions 24, 28 each being curved when viewed in cross sectional side view, as can be seen in Figure 2. The outer edge of each end portion 24, 28 thus forms an arc of a circle. It is desirable that the degree of curvature is quite 20 small, and therefore the radius of curvature may be greater than the radius of the middle portion 26. In the shown embodiment, the radius of curvature is about 40mm. This results in a reduction of the thickness of the outer body portion 22 towards the open end 18, 20. Although this reduction in thickness is 25 necessary to give effect to the invention, should the thickness reduction be too great the ends of the outer body portion 22 can become too difficult to manufacture, and liable to damage during installation. It is considered that a thickness reduction of 40% to 90% of the thickness of the middle portion produces a good result. The ends of the end portions 24, 28 can be rounded 30 off, for instance with a circular arc of radius about 1mm. The lower body portion 14 extends to a lower end 30, and has an internal bore 32 extending axially inwards of the lower end 30. The bore 32 is sized to receive a vertical railing section (not shown). It is considered desirable to have consistency in dimensions, so that the internal diameter of the bore 32 is the 6 same as that of the bore 16 (50mm), and the external diameter of the lower body portion 14 is the same as that of the middle portion 26 (60mm). The lower end 30 of the lower body portion 14 does not feature a radius reducing region comparable to the first and second end portions 24, 28 of the 5 upper body portion 12. Each of the open ends 18, 20, 30 has a screw aperture 34 located nearby, in which a grub screw can be located to secure the rail section in position. It will be appreciated that the thickness of the railing joint (about 5mm) may not be sufficient to provide sufficient engagement for a grub screw. It is therefore 10 considered desirable to provide a thickened portion 36 about each screw aperture 34. The present invention proposes locating the screw apertures 34 of the upper body portion 12 on the underneath of the upper body portion 12, adjacent the lower body portion 14. This assists in maintaining as smooth as possible a 15 form for the top and sides of the upper body portion 12. Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention. 20