BACKGROUND OF THE INVENTION

This invention relates to a window stay.

A window stay is a piece of hardware by which a window sash can be hingedly mounted within a window frame. The term "window stay" is broadly used to indicate a hinge for hingedly mounting a sash in a window frame but not necessarily itself hold the window sash in an adjusted open position. Thus while in the preferred form of the invention as described herein the window stay serves the purpose of hingedly mounting the window sash in a frame it does not itself hold the sash in an adjusted open position. However, by incorporating friction in, say, at least one pivot joint the stay can be capable of holding the window sash in an adjusted open position.

Typically a window sash is mounted into a window frame by a pair of window stays in the factory of the window manufacturer. However, there are situations where a window installer may wish ,to be able to fit a window sash to a window frame on the building site. This, however, requires the window installer to install the frame and sash mounting plates using fixing methods or special tools.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a window stay having a construction which enables a window installer to be able to readily and easily fit a window sash to a window frame at a building site.

Broadly in one aspect of the invention there is provided a frame mounting plate, a sash mounting plate, an arm pivotally coupled to the sash mounting plate, a carriage guide extending longitudinally of the frame mounting plate, a carriage slidingly mounted with the carriage guide to be movable along the frame mounting plate, said sash mounting plate being pivotally coupled to the carriage, and said arm being pivotally coupled to a mounting means which is clip mountable to the frame mounting plate.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of the window stay according to one preferred embodiment in the fully closed position,

Figure 2 is an end elevation view of the window stay in the full closed position, Figure 3 is a perspective view of the window stay in the fully opened position,

Figure 4 is a view similar to Figure 3 but showing the window stay prior to final assembly,

Figure 5 is a top perspective view of an end clip for mounting the arm of the window stay to the frame mounting plate,

Figure 6 is an underside perspective view of the end clip, and

Figure 7 is a cross-section view through a screw hole of the frame mounting plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The window stay according to the present invention is typically referred to as a "two bar" stay. As a consequence the stay comprises a frame mounting plate 10, a sash mounting plate 11 and a single arm 12 coupled between plates 10 and 11. Thus arm 12 is coupled at one end to the sash mounting plate 11 via a pivot 13. Openings 14 are provided in the sash plate 11 to also facilitate mounting to the window sash by a screw or the like passing therethrough.

The sash mounting plate 11 is mounted via pivot 15 to a flange 24 of a carriage 16 which is mounted for sliding movement along the length of the frame mounting plate 10.

The end of the arm 12 opposite to that coupled to the sash mounting plate 11 is, pivotally coupled to a mounting or clip

17 via a pivot 18. As will hereinafter be described clip 17 is adapted for snap-lock fitting to one end of the frame mounting plate 10.

The frame mounting plate 10 is provided with a plurality of countersunk openings 19 whereby the frame mounting plate can be attached to the window frame. An opening 20 can be formed in clip 17 (as shown) to allow access to the opening 19 which would otherwise be covered by clip 17.

The frame mounting plate 10 is, in the preferred form, of extruded aluminium and in cross section can be described as being of substantially "G" shape. There is thus formed a longitudinally extending channel 21 and a lateral flange 22, the latter providing a carriage bearing surface 23.

Flange 22 is undercut beneath the carriage bearing surface 23 and this enables the countersunk openings 19 to be formed directly into the frame plate 10 as can be more clearly seen in Figure 7. Openings 19 are formed as a secondary operation after extrusion of plate 10. The countersunk nature of openings 19 enables the heads of the fixing fasteners (eg screws) to be situated below the bearing surface 23. Consequently this carriage bearing surface 23 does not itself need to be undercut. As a result bearing surface 23 provides a large contact area with the sliding surface of the flange

distributed over this larger area resulting in a significant reduction in wear and/or the ability to carry a heavier load.

A longitudinal rib 25 extends along one side of the carriage 16 and this is profiled to slidingly fit within the longitudinal channel 21.

Channel 21 is in part defined by two curved surfaces 26. The presence of these curved surfaces 26 enable the rib 25 of the carriage 16 to engage with maximum surface area within the channel 21. Also the tolerance fit of the rib 25 in the channel 21 with its curved surfaces 26 enables the carriage to freely pivot and accommodate any cavity variations.

In the preferred form of the invention the carriage 16 is formed from a plastics material and the interaction of the rib portion 25 in the channel 21 with its curved surfaces 26 results, in the preferred form of the invention, in the carriage not requiring a metal insert for strengthening purposes.

The stay is primarily intended for use in a casement window. Thus with the stay which is situated at the top end of the window the carriage can, according to the construction described above, slide more easily with reduced wear as the carriage rides on a curved surface rather than a point

contact as is often the case with existing stays of this type.

As can be seen in the drawings the end of the sash mounting plate 11 which is coupled to the sliding carriage 16 is stepped downwardly. The carriage 16 includes a land 27 which when the stay moves toward and is in the fully closed position engages with the underside of the sash plate 11 adjacent the stepped portion. This provides a support for the sash when in the closed position to thereby prevent sag of the sash in the frame.

The end clip 17 is formed by a plate 28 with a longitudinally extending finger 29 at one end thereof. The other end of plate 28 is provided with an end block 30. Extending from block 30 along one side of plate .28 is a chamfered spine 31 which engages into the frame plate channel 21. The finger 29 has a pair of teeth 32, these teeth being engageable in a pair of correspondingly positioned slots or notches 33 in the frame plate 10 when the clip 17 is located in position as hereinafter described.

In the preferred form spine 31 has a profiled lead in end 31a which terminates adjacent the innermost tooth 32.

On the building site a window installer who wishes to install the sash into an already installed frame will receive the

window frame with the frame mounting plate 10 already fastened in position. The installer can thus install the frame into the building construction. Furthermore the installer will receive the window sash which will have attached thereto the sash mounting plate 11, this sash plate carrying arm 12 with the carriage 16 and the end clip 17 pivotally coupled to the sash mounting plate 11 and arm 12 respectively.

To install the window the installer will simply position the sash in a plane parallel to that in which it lies in an open position (which can be the fully open position as illustrated) relative to the frame. Consequently the sash mounting plate 11, arm 12, sliding carriage 16 and end clip 17 will be orientated relative to the frame mounting plate as shown in Figure 4. The installer can then simply move the window sash relative to the frame such that the sliding carriage comes into engagement with the frame mounting plate 10 so that the rib 25 engages in the sliding channel 21. This will be followed by the end clip 17 slidingly engaging with the frame plate 10 from the same end as the sliding carriage so that the chamfered spine 31 engages into the channel 21.

The aforementioned movement is complete once the teeth 32 snap lock into the notches 33 in the frame plate 10. At such point the shoulder 34 of end block 30 comes into engagement

with or be immediately adjacent the end of the frame mounting plate 10. By the teeth 32 snapping into the notches 33 the stay is effectively assembled and held together. This enables the sash to be fitted to the frame without any fitting tools. As can be more clearly seen in Figures 5 and 6 at least the distal tooth 32 is slightly hook shaped or undercut so that it engages back under the frame mounting plate. Thus, as the window is opened and carriage 16 slides toward clip mount 17 the hooked surface of tooth 32 is forced into closer contact with the edge of the slot 33. This provides a further restriction to tooth 32 trying to ride up out of its engagement in slot 33.

The forces that the end clip 17 must withstand get larger as the sash moves into the closed position. However, the security of the clip 17 is guaranteed as the arm 12 moves over the clip finger 29 as the sash approaches the closed position thereby preventing the clip from disengaging as the sash closes. It will be noted that arm 12 is stepped at 37 and this stepped portion coincides with the sloped/stepped part 38 of finger 29 as the stay moves to the fully closed position.

Preferably carriage 16 also includes a projecting engagement portion 39 which, as seen in Figure 3, overlaps with the end of finger 29 of clip mount 17. This applies a downward pressure on finger 29 so as to force projections 32 into

slots 33 in the event the projections 32 have tended to ride up out of the slots 33. This interengagement of the carriage 16 and clip 17 also provides an end stop for the stay in its fully opened position.

For further security, however, an opening 35 is provided in end block 30 whereby the installer can, if so choosing to do so, insert a mechanical fastener through opening 35 and into the window frame to thereby further secure the clip 17 in position.

End block 30 has the dual function of a sash riser block. It therefore has a chamfered face 36 which can engage with the sash as the window approaches the closed position to thereby lift the sash into its correct orientation in the frame and support the sash against sagging in the frame.

To facilitate "squaring" of the sash in the frame in a simple yet effective manner the openings 19 in frame mounting plate 10 can be elongate with their major axis extending longitudinally of the frame plate 10. The installer can thus readily adjust the position of the frame plate by simply loosening off the fixing screws, moving the frame plate longitudinally to the desired position and then retightening the screws.