This invention relates to hinge assemblies. It has particular application in situations where a hinged joint must so far as possible, seal against the passage of fluid therethrough. However, the invention is not restricted to such applications.

Typical situations in which a hinge will also seek to form a sealed joint are in shower doors and screens, and portable screen assemblies. Known hinges used in these applications are typically of the brush type or use a flexible membrane between the hinged bodies. The former are prone to leakage. The latter, while initially providing a good seal, are vulnerable to cracking and eventual leakage or total failure.

The present invention is directed at a hinge assembly which requires little or no deformation of its component parts to achieve a substantial seal between hinged bodies. According to the invention, a hinge assembly comprises first and second bodies, each having an edge along which extends an elongate element. A cylindrical surface is formed on each element, and the bodies are held such that the cylindrical surfaces are in engagement. Each body remains rotatable about its respective cylinder axis, enabling one body to turn relative to the other about an axis parallel to the respective cylinder axes, but not fixed relative to either body. Preferably, each cylindrical surface is formed with grooves extending parallel to the cylinder axis and creating ridges therebetween. With this arrangement, the surfaces are held in engagement with the ridges of one surface in the grooves of the other.

To hold the cylindrical surfaces in engagement in an assembly of the invention, the respective cylinder axes must be either drawn together, or held at a fixed spacing which secures the engagement of the surfaces. This can be accomplished by the use of a bracket at either end of the cylindrical surfaces, each bracket extending between rotatable mountings on the

respective cylinder axes. Provision can be made for maintaining an element of pressure at the line of engagement between the cylindrical surfaces. Where brackets of the kind just referred to are used, this can be accomplished by one or more springs or other resilient element in the brackets urging the cylinder axes towards each other. The level of pressure may be adjustable, and selected according to requirements, but will normally be relatively low. Preferably it is sufficient to cause minor deformation of the surfaces on the line of engagement and thereby ensure a seal.

The engaging cylindrical surfaces in hinge assemblies of the invention can be formed in any suitable material, but resilient materials are preferred. Rubber or synthetic rubbers can be suitable, as can plastics materials such as PVC. PCV has the advantage of being adaptable to different degrees of hardness. In one preferred feature of the invention at least one of the cylindrical surfaces comprises an inner and an outer layer, with the outer layer being soft relative to the inner layer. It is also preferred that at least one of the cylindrical surfaces be a plastics extrusion, and these preferred features can be combined in a cylindrical surface formed as a co-extrusion of plastics materials of different relative hardnesses.

The circumferential extent of each cylindrical surface will of course determine the extent to which the hinge will allow one body to turn relative to the other. Where the cylinder surfaces are of the same diameter, and that diameter at the mean line of engagement with the other surface is greater than the thickness of the respective body, if each cylindrical surface extends around an arc of at least 270°, one body can be turned through 360° relative to the other.

It is not essential in hinge assemblies of the invention that the respective engaging surfaces are both cylindrical, or precisely matching. Provided at least one of the surfaces is of constant arcuate cross-section, and

can be held in engagement with the other, then the body on which it is mounted will be able to rotate or at least pivot about an axis defined by the engaging surfaces. Different mechanisms can be used to hold the surfaces in engagement. In one such embodiment, a bracket can be mounted at and for rotation relative to each end of the arcuate surface on the second body, and slidable relative to the surface of the first. This arrangement would be suitable for example where a hinge assembly of the invention was used between a flat or substantially flat surface on a first body, and an arcuate surface formed along an edge of a second body. It will be appreciated that in such circumstances a third body could be mounted on the first body at a suitable distance from the second body to avoid interference. This kind of arrangement can be of value in mounting display panels or the like for rotation about vertical axes on a vertical wall. Engagement between the surfaces of the hinge assembly can of course extend the full length of the respective edge to provide substantial support for the mounted panel. The mounting mechanism itself can be designed so as to be readily dismantled, enabling mounted panels to be easily removed and replaced.

With the surface to surface engagement of the elements of hinge assemblies according to the invention it is relatively difficult to inadvertently catch elements or body parts therein. This is particularly useful when the invention is embodied in a shower door for example where different parts of the body are sometimes used to effect closure.

Another benefit of the invention is the controllable tightness of the hinge itself. Particularly when the hinge is oriented vertically, movement of one body relative to the other about the hinge will normally require a positive effort, even if the pressure between the engaging surfaces is relatively low. With increased engagement pressure, greater force is required to effect a turn. As noted above, this can be adjustable, enabling one hinge to be used in different applications and adapted to require different turning forces.

An embodiment of the invention will now be described by way of example, and with reference to the accompanying drawings wherein:

Figures 1 and 2 are perspective views from opposite sides of a hinge according to the invention;

Figure 3 is an exploded view of the hinge of Figures 1 and 2 showing the component parts; and

Figures 4, 5 and 6 are cross-sectional views of the hinge of Figures 1 and 2, in different orientations.

The hinge shown in Figure 1 has two bodies 2,4 with edges in the form of cylindrical surfaces 6,8 formed with externally directed ridges and grooves. As is apparent from Figures 4 to 6, the bodies 2 and 4 are hollow extrusions, typically of aluminium or aluminium alloy, the ends of which are closed by caps 10 and 12. The caps 10 and 12 extend over the ends of the cylindrical surfaces 6 and 8 where they are secured by screws 14 (Figure 3) which also secure the brackets 16 which hold the cylindrical surfaces 6 and 8 in close engagement with the ridges of one surface engaging the grooves of the other. The screws 14 are concealed in the body of each bracket 16 by cover 18.

The brackets 16 define a fixed spacing between the cylinder axes. However, they can be of adjustable length, enabling the spacing to be reduced and thereby applying pressure between the engaging surfaces. They can also be fitted with some resilient mechanism (not shown) such as a spring to continuously urge the surfaces against each other.

The screws 14 are located at the axes of the respective cylindrical surfaces 6 and 8. This enables the cylindrical surfaces to rotate relative to each other while they remain in engagement, to enable the bodies 2 and 4 to hinge towards or away from one another. It will be appreciated then, that the

assembly as illustrated in Figure 1 has the same components on either side of the line of contact between the cylindrical surfaces.

As is apparent from Figure 3, and from Figures 4 to 6, the cylindrical surfaces 6 and 8 are each formed on an elongate element, mounted on the edge of the respective body 2,4. Each of these elements is typically a co- extrusion of PVCs of different hardness, with the main body 26 comprising the harder plastic, and the ridges 28 being formed in the softer plastics. This arrangement allows for the ridges to deform slightly as they engage in the grooves of the opposite surface, and this assists in preserving an effective seal against the passage of fluid and particularly water, across the boundary defined at the hinge. By using a harder plastics material for the main body of the elements 6,8 the elements can secure themselves on the bodies 2,4 by means of their own resilience. However, the opposite edges are received in grooves 20 to prevent them rotating relative to the body upon which either is mounted. Axial movement relative to the body edge is of course prevented by the caps 10 and 12. Each element is also formed with fingers 22 which engage groove 24 in the respective aluminium body to assist in holding the respective element in place.

As can be seen particularly from Figure 6, the diameter of each elongate element 6,8 at its mean line of engagement with the other element is greater than the thickness of the respective body 2,4 upon which it is mounted. This enables the hinged bodies 2,4 to rotate relative to each other through 360° without making contact. This is particularly valuable in doors or shutters having multiple hinged bodies, as it enables the bodies to be folded in either sense to reduce the extended linked bodies to a stack, with one on tope of another.

The particular embodiment of the invention described above has identical matched cylindrical surfaces maintained in constant engagement.

However, and as noted above, the surfaces on the elongate elements do not have to match or indeed be cylindrical in cross-section. Depending on the purpose to which the hinged joint is to be put, the cross-section of the respective surfaces can be of any chosen shape, provided that they are held in engagement, and one is able to rotate or pivot relative to the other. Matching cylindrical surfaces can of course be held in engagement quite easily by using brackets 16 of the kind illustrated, as the spacing between the cylinder axes remains substantially constant. When the respective surfaces are not matched, then resilient and/or sliding mechanisms will be required to maintain the necessary engagement.