FIELD OF THE INVENTION

This invention relates to assemblies for attaching elements such as handrails, to the upper ends of stanchions, in balustrades. The invention is particularly useful for stainless steel balustrades and is described herein with reference to stainless steel balustrades, but it can be used in various other applications where any handrail needs to be fixed to a hollow stanchion. BACKGROUND TO THE INVENTION

Stainless steel balustrades typically include a number of spaced apart posts or stanchions, with a top rail or handrail extending along the top of the stanchions (and thus the top of the balustrade) and usually with an infill (such as horizontal or vertical rods or cables or glass panels) extending between the stanchions, below the handrail. The stanchions are often hollow cylindrical tubes and the handrails are attached to the stanchions via pins extending between the upper end of each stanchion and the handrail. The pins can be attached to the handrails by various methods and this typically includes plates that are attached to the undersides of the handrails.

The attachment of the pin to the upper end of the stanchion in these balustrades requires welding of a domed cap to the stanchion and welding the pin to the domed cap. The pin can optionally also be attached to the stanchion by way of braces or other parts extending between the wall of the stanchion and the pin (typically below the domed cap, to hide it from view). These welds are unsightly and in order to obtain an acceptable appearance for the balustrade, the upper end of the stanchion, domed cap and pin need to be polished by hand after welding. This method of attaching the pin to the stanchion is costly because it requires costly steel

components to support the pin in relation to the stanchion, it requires welding and it requires finishing. Further, heat from the welding operations can adversely affect the mechanical properties, appearance and/or corrosion resistance of the stainless steel. An alternative attachment of pins to the upper ends of stanchions includes casting a solid stainless steel body that includes the pin and a part that can fit inside the upper end of a hollow stanchion. These attachments also suffer from the shortfalls of requiring costly material and costly polishing operations, but more importantly, these attachments are prone to loose fits or requiring excessive force to fit them on the stanchions, because of variations in the inner dimensions of hollow stanchions. Some of the most common forms of hollow stanchions are hollow cylindrical tubes that are roll formed from stainless steel plate and, while the outer diameters of these tubes are manufactured with precision, the wall thicknesses of the tubes are allowed (by internationally accepted norms) to vary up to 10%, so that the inner diameters of roll-formed stainless steel tubing varies greatly.

The present invention seeks to provide cost-effective, yet strong and appealing means for attaching handrails to stanchions, that can compensate for variations in inner dimensions of stanchions.

SUMMARY OF THE INVENTION

According to one aspect the present invention there is provided an assembly for attachment to an upper end of a hollow stanchion, said assembly comprising:

an elongate metal pin having a free end and a fixed end;

a fixture formation on the free end of the pin;

a polymeric plug attached to the fixed end of the pin, with the fixed end of the pin embedded in the plug, said plug having a peripheral surface that is shaped and dimensioned to be receivable inside an internal cavity of the stanchion, with an interference fit; and

a metal cap extending around the pin, adjacent the plug;

The term "interference fit" is intended herein to include a wide variety of fits, varying from a "locating interference fit" (a rigid fit with no bore pressure) to a "force fit" (which involves substantial force and/or stresses). Preferably, the fit between the polymeric plug and the stanchion is a "press fit" - which means that there is significant interference between the components, akin to a "force fit", but the components can be pressed together without a need for other techniques (such as thermal expansion). The plug may be cylindrically shaped and may be shaped to fit inside a cylindrical internal cavity of the stanchion. The plug may define a plurality of internal cavities, disposed between the pin and an outer peripheral wall of the plug, preferably with circumferentially spaced webs extending between the peripheral wall and the pin. The plug may be attached to the fixed end of the pin by an interference fit between the pin and a central cavity of the plug in which the pin is received, by forcing the fixed end of the pin into the central cavity, by moulding the plug over the fixed end of the pin, or the like. The interference fit may be a press fit. The metal cap may be attached to the pin with an interference fit and may be domed, to extend between the pin and an upper periphery of the stanchion, to cover an upper end of the plug. The interference fit between the metal cap and the pin may be a press fit, but it may instead be a location interference fit. The fixture formation may include a metal plate that is attachable to a handrail and the metal plate may be pivotally attached to the free end of the pin.

The fixture element, pin and/or metal cap may be of stainless steel and the plug may be moulded from of a thermoplastic material such as nylon.

The invention extends to a stanchion on which the assembly described above has been fitted by inserting the plug into an internal cavity of the stanchion, with an interference fit - preferably such that a periphery of the cap lies adjacent a periphery of the stanchion, so that the plug is concealed, at least substantially, but preferably completely, from view.

According to another aspect of the present invention, there is provided a method of assembling a balustrade, said method comprising attaching the assembly described above to an upper end of a stanchion by inserting the plug of the assembly into an internal cavity of the stanchion with an interference fit, and attaching a handrail to the fixture element of the assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show how it may be carried into effect, the invention will now be described by way of non-limiting example, with reference to the accompanying drawings in which:

Figure 1 shows a top three-dimensional view of an assembly according to the

present invention;

Figure 2 shows a top three-dimensional exploded view of the assembly of Figure 1 ; Figure 3 shows a bottom three-dimensional view of a plug of the assembly of Figure 1 ; and

Figure 4 shows a side view of the plug of Figure 3, with internal details shown in broken lines.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to the drawings, an assembly according to the present invention is generally identified by reference number 10.

The assembly 10 includes an elongate pin 12 with a free end which is shown in the drawings as an upper end 14 and a fixed end which is shown in the drawings as a lower end 1 6. A fixture formation in the form of a plate 18 is attached to the upper end 14 and a plug 20 is attached to the lower end 16, with a cap 22 extending over an upper end of the plug, around the pin 12.

The plate 18 is of stainless steel and has a part-cylindrical shape, to allow it to be attached in any one of a number of ways known in the art, to the underside of a cylindrical handrail of a balustrade, e.g. by drilling holes through the plate and attaching the handrail with screws or rivets. The plate 18 is attached to the upper end 14 of the pin 12 by a pivot mechanism 24, which allows the handrail to be attached to the pin at various angles, e.g. where the pin is installed vertically (on a vertical stanchion) on a ramp and the handrail is required to follow the slope of the ramp. However, many alternative attachments of the plate 18 to the upper end 14 is possible, including welding the plate to the upper end before installing it in the assembly 10. Also, the plate 18 is merely an example of a fixture formation and the handrail can be attached to the upper end 14 in various other ways. Depending on the fixture method selected, the plate 18 could be required to be thick enough to provide sufficient strength and, merely as an example, it could have a thickness of about 1 .5 mm.

The pin 12 is an elongate, solid, cylindrical stainless steel bar, but it could instead have any other cross-sectional profile and it could be hollow. The pin 12 has to be sturdy for supporting the handrail and transferring any loads exerted on the handrail to the stanchion below, and merely as an example, the pin could have a diameter of about 12 mm.

The cap 22 preferably has a domed shape with a round central aperture 26 through which the pin 12 is receivable with an interference fit, preferably a press fit, but possibly a locating interference fit. While a domed shape is preferred for aesthetic and practical reasons in the illustrated embodiment, the cap 22 can have any shape and the aperture 26 can have any shape that allows it to fit with an interference fit around the pin 12. The cap 12 is pressed from stainless steel plate and does not bear significant loading and can be made from a relatively thin plate, e.g. 0.7 mm thick plate, or other thickness. The outer circumference of the cap 22 is preferably the same as the outer circumference of a stanchion on which the assembly 1 0 is to be fitted, for aesthetic appeal, but the outer shape and dimensions of the stanchion and cap need not be matched. The pin 12, plate 18 and cap 22 are preferably polished before being attached together and given their simple geometrical shapes in the illustrated embodiment, they can be polished at relatively low cost in automated processes. The plug 20 is a moulding of suitably strong polymeric material, such as nylon and it can be solid or partly hollow. In the illustrated embodiment, the plug 20 and has a generally cylindrical shape, suitable for fitting inside a hollow, cylindrical stanchion. The plug 20 in the illustrated example has a cylindrical peripheral wall or outer wall 28 and a cylindrical inner wall 30 with an annular gap 32 between the inner and outer walls and with eight radial webs 34 extending between the inner and outer walls at equal circumferential spacing, so that internal cavities are formed in the annular gap between the webs.

A cylindrical central cavity 36 is defined inside the inner wall 30, has a central opening 38 at its top and is closed at its bottom by a bottom wall 44. The upper end of the plug 20 forms a dome-like head 42 that can fit inside the cap 22 and the circumference of the head 42 is preferably enough to fit snugly inside the

circumference of the cap. The outer circumference of the outer wall 28 is sized to fit inside an internal cavity of the stanchion on which the assembly 10 is to be fitted, with an interference fit, but the wall thickness of the stanchion is typically far more than the thickness of the cap 22, so the circumference of the head 42 typically protrudes beyond the circumference of the outer wall 28. A circumferential groove 44 can be defined between the head 42 and the outer wall 28.

The plug 20 described above has a cylindrical peripheral surface (being the circumference of the outer wall 28), but the plug can have any other peripheral surface, as long as it fits inside the internal cavity at the top of the stanchion, with an interference fit - preferably a press fit. In other embodiments of the invention, the plug and/or the internal cavity of the stanchion, can be non-cylindrical.

The assembly 10 can be made by pressing the lower end 1 6 of the pin 12 through the aperture 26 of the cap 22 and into the central cavity 36 of the plug 20, preferably with a broach press, but possibly with a hydraulic press, hammer, or the like, until the cap fits tightly on the head 42 and the lower end 16 touches the bottom wall 40. Instead, the pin 12 can be positioned so that its lower end 1 6 extends into the mould in which the plug 20 is moulded, so that the plug is moulded over the lower end, but this would require that the cap 22 be fitted on the plug afterwards. In either case, the lower 16 end of the pin 12 is sturdily embedded in the plug 20 and the cap 22 extends around the pin and over the head 42.

The assembly 10 is attached to the upper end of the stanchion, which is a hollow cylindrical stanchion in the case of an assembly as illustrated, by inserting the lower end of the plug 20 (which is preferably slightly tapered) into the internal cavity at the upper end of the stanchion and forcing the plug into the internal cavity, preferably with a broach press, or similar press arrangement, until the upper circumference of the stanchion makes contact with, or is very near, the circumference of the cap 22, so that the plug is concealed from view. The plug 20 is preferably forced into the cavity of the stanchion by exerting the pressing force downwards on the plate 18, so that the force is transferred to the plug via the pin 12.

Once the plug 20 has been inserted into the upper end of the stanchion, the installation of the assembly 10 has been completed and no further attachment or finishing is required and a handrail can be attached to the plate 18 to complete the balustrade. Accordingly, no welding or polishing is required to install the assembly 10. The attachment between the assembly 10 and the stanchion resulting from the interference fits between the stanchion and the plug 20, as well as the attachment of the pin 12 to the plug, are adequately strong, when compared to conventionally attached (welded) components and it can accommodate variations in internal dimensions of the stanchion while still being sturdy and durable. Further, since the plug 20 is made of a softer material than stainless steel, it can absorb shocks and vibration and given its tight fit against the walls of the stanchion, it prevents water ingress into the stanchion. It is also possible to assemble the components in a different order, e.g. to fit the plug 20 inside the stanchion, place the cap 22 on the plug and then insert the pin12 through the aperture 26 and opening 38 into the cavity 36. The assembly 10 can be supplied as a standard fitting for a predetermined hollow cylindrical stanchion and can be installed quickly, easily and cost effectively, with low skill requirements and without the need for any specialised tools, power, etc. on site.