HINGE FOR PIVOT WINDOWS This invention relates to a hinge for a pivot window, particularly, but not exclusively, a pivot window for installation in an incline roof. Such hinges have been proposed heretofore and consist of two hinge parts, each hinge part having a base plate for securement respectively to a frame and to a sash of a window. Both plates are intended to be screw fastened to their respective surface with both having at least two spaced spigot pins on their respective reverse face to locate in corresponding socket holes provided in their respective surface. One hinge part has on an obverse face guide means in the form of a part-circular guide having two members with the other hinge part having on its obverse face a slide member adapted to be displaceable in the guide between the two members. The slide member of the other hinge part also defines a tilting axis for sash movement near the closed position with the axis being outside the window thickness. The other hinge part is pivotable with respect to the one hinge part on a hinge pin carried by the slide member and is movable from a position within the window thickness to a position outside said thickness during movement of the sash away from the closed position by swinging around said tilting axis.

A problem with known examples of such hinges is the control of the friction conditions. The slide member is desirably capable of maintaining any position in the guide members corresponding to keeping the window sash in a suitable ventilating position, but also the friction should not be so high that it hampers the opening and closing of the window and causes noticeable wear on the involved parts, that is on the part circular outside faces of the slide member and the inside faces of the two members of the guide means. With a view to ensuring the position maintaining facility, it is known to build into the concave side wall of the outer guide member, a spring segment or blade spring which to a suitable extent urges the opposite side of

the slide member against the convex side of the inner guide member. Proposed solutions to these problems have been made, for example in EP 0438484 the slide member has been sleeved. Also, current practice also provides for a preformed block to be inserted on the lower portion of the guide member at its leading end to entry to the passageway. These proposas involve complex assemblies and therefore labour costs. The hinge parts, in particular the guide members and slide member, are made of metal, and, with the purpose of limiting the friction between and the wear on the surface sliding on each other, the hinge now and then should be maintained by lubricating, this being considered a drawback in use. Lacking maintenance in this respect may under adverse conditions result in seizing of the sliding surfaces and thus impeding the manoeuvring of the window and finally destruction of the hinge.

An object of the present invention is to obviate or mitigate the problems described above.

Accordingly, the present invention is a hinge for pivot windows comprising two hinge parts, both hinge parts having a base plate for securement respectively to a frame and to a sash of a window, a first hinge part having on an obverse face guide means of part-circular formation and formed of two spaced guide members defining a passageway therebetween with a second hinge part having on its obverse face a slide member adapted to be displaceable in the passageway of the guide between the two guide members whereby the two guide members and/or the slide member are all formed of a hard wearing plastics material.

Preferably, the base plate and guide members of the first hinge part are integrally formed. The passageway is desirably a blind slot, the guide members being joined at one end. The first hinge part has preferably on a reverse face at least two load-bearing, spigot pins to locate in corresponding socket holes provided in

a respective surface of a frame and of a sash of a window to which the hinge is to be secured, the load-bearing, spigot pins being integrally formed in the first hinge part.

Beneficially at the entry to the passageway, part of the obverse face at one end of one of the two guide members is rebated and a location spud is provided on the base plate adjacent thereto and on the opposed side of the passageway, and a guide plate straddling the passageway is secured to said rebated portion and over said location spud, the guide plate serving to retain the slide member in the passageway when displaced therein.

Preferably also, the second hinge part has on a reverse face of the base plate at least two load-bearing, spigot pins located in corresponding socket holes provided in a respective surface of a frame and of a sash of a window to which the hinge is to be secured. The slide member is desirably of a substantial C-shape in which the upper part enters the passageway and the outer end of the lower part is pivoted to the second hinge part. An elongate guide pin is beneficially provided to enter the passageway in front of the slide member, the guide pin being secured to the base plate of the second hinge part. The guide pin is desirably secured to the base plate of the second hinge part by a fastening. The guide pin may be of a resilient material having a dimension greater than the spacing between the guide members.

Entry of the guide pin into the passageway between the guide members preferably results in deformation of the resilient material thus increasing the facial contact load and consequently increasing the sliding friction in the passageway.

Preferably further, one side of one guide member bounding the passageway is recessed between two bosses, one at each end of the passageway and an arcuate leaf spring of similar width of the side is positioned thereat, the spring having curved ends, each to clip over a respective boss and be held thereby.

Alternatively, one or both guide members may be provided with a slot substantially along their length with the part of the guide member adjacent to the

passageway being separated from the plate whereby to provide an additional resilience with that part thereby being made more resilient. Alternatively further, the side of each guide member defining the passageway may be provided with a lengthwise series of indentations.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying schematic drawings, in which:- Fig. 1 is a perspective front view of a first hinge part of a two part hinge according to the present invention, shown without a guide plate ; Fig. 2 is a perspective front view of the second part of the hinge, showing also a slide member; Fig. 3 is a front view of the first hinge part showing the slide member and guide pin in position in the passageway, and the guide plate in position; Fig. 4 is a rear view of the second hinge part; Fig. 5 is a plan view of the first plate to a smaller scale ; Fig. 6 is a front view of a first modified first hinge part; Fig. 7 is a perspective view of a second modified first hinge part; Fig. 8 is a perspective view of a third modified first hinge part; and Fig. 9 is a perspective view of a fourth modified first hinge part.

Referring to the drawings, a hinge for pivot windows comprises two hinge parts 10,12. Both hinge parts 10,12 have a base plate 14,16 for securement by screw fastenings through screw holes 18 respectively to a frame (not shown) and to a sash of a window (not shown). A first hinge part 10 has on an obverse face guide means of part-circular formation and formed of two spaced guide members 20,22 defining a passageway 24 therebetween with a second hinge part 12 having on its obverse face a slide member 26 adapted to be displaceable in the passageway 24 of the guide between the two guide members 20,22.

The base plate 14 and/or guide members 20,22 of the first hinge part 10 are integrally formed of a hard wearing plastics material. The passageway 24 is a blind slot, the guide members 20,22 being joined at one end. The first hinge part 10 has on a reverse face two load-bearing, spigot pins 28 to locate in corresponding socket holes (not shown) provided in a respective surface of a frame and of a sash of a window to which the hinge is to be secured, the load-bearing, spigot pins 28 being integrally formed in the first hinge part. At the entry to the passageway 24, a recess 25 is provided in the base plate 16 and a part of the obverse face at one end of guide member is rebated at 23 and a location spud 30 is provided on the base plate 14 adjacent thereto and on the opposed side of the passageway 24. The second hinge part 12 has on a reverse face of the base plate 16 two load-bearing, spigot pins 34 to locate in corresponding socket holes (not shown) provided in a respective surface of a frame and of a sash of a window to which the hinge is to be secured. The base plate 16 of the second hinge part 12 and pins 34 are integrally formed from hard wearing plastics material. The slide member 26 is of substantial C-shape in which the upper part 26A enters the passageway 24 and the outer end of the lower part 26B is pivoted on a hinge pin at 36 to the second hinge part 12. This hinge pin also provides the tilting axis for the hinge. A guide pin 38 is provided to enter the passageway 24 in front of the slide member 26. The guide pin 38 is secured to the base plate 16 of the second hinge part 12 by a fastening through hole 40.

A guide plate 32, straddling the passageway 24, is secured to said rebated portion 23 and over said location spud 30. The guide plate 32 serves to retain the slide member 26 in the passageway 24 when displaced therein.

Right and left hand versions of the hinge are provided for both lateral sides of the window.

Both base plates 14,16 have integral therewith a mounting block 44 into which a screw fastening (not shown) can be screwed to secure a flashing or waterproof membrane in conventional manner.

In a first modification, the slide member 26 is of metal.

In a second modification, the second hinge part is of metal, with the mounting block secured thereto.

In a third modification, one side of one guide member bounding the passageway 24 is recessed between two bosses 50, one at each end of the passageway 24 and an arcuate leaf spring 52 of similar width of the side is positioned thereat, the spring 52 having curved ends 54 each to clip over a respective boss 50 and be held thereby.

In a fourth modification, one or both guide members 20,22 are provided with a slot 56 substantially along their arcuate length with the part of one or both guide members adjacent to the passageway 24 being separated at 27 from the plate 14 whereby to provide an additional resilience with that part thereby being made more resilient.

In a fifth modification, the side 44 off one or both guide member 20,22 defining the passageway 24 is provided with a lengthwise series of smooth curved indentations 58 to provide pre-determined sash open positions.

In a sixth modification, the guide pin 38 is of a resilient material having a dimension greater than the spacing between the two guide members. Entry of the guide pin into the passageway between the guide members results in deformation of the resilient material thus increasing the facial contact and consequently increasing the sliding friction in the passageway. Alternatively, the guide pin 38 is of solid material having an outer covering which is resilient for compression when positioned between the guide members, and capable of having an inherent restoring force when moved out of the guide members, or in connection with the fifth modification when

entering the indentations. Alternatively further, the guide pin 38 is elongate and is provided with two inwardly curved arms 42 which are positioned as shown in Fig. 3 at the leading end of the guide pin 38 as it enters the passageway 24. The arms 42 are resilient. The resilient material used has hard wearing characteristics on the surfaces to be in contact with the passageway 24.

In use, a pair of hinges as described above are fitted, one of he hinges at each side of an inclined window with a first guide plate 10 being fitted to a side component of the window frame and the second guide plate 12 being fitted to a corresponding side of a sash of the window. The window is opened, closed and capable of pivoting about the tilting axis in a conventional manner.

A hinge as described above is advantageous over previous proposed hinges in that it does not require lubricating maintenance, is cheaper to manufacture, involves less parts and is more readily assembled than heretofore.

Variations and modifications can be made without departing from the scope of the invention described above and as claimed hereinafter.