GB2370605A

GB2370605A - Security friction supporting stay

Info

Publication number: GB2370605A
Application number: GB0130376A
Authority: GB
Inventors: Martin Crawley Franklin
Original assignee: Nico Manufacturing Ltd
Current assignee: Nico Manufacturing Ltd
Priority date: 2000-12-20
Filing date: 2001-12-19
Publication date: 2002-07-03
Anticipated expiration: 2021-12-19
Also published as: GB0031150D0; GB2370605B; GB0130376D0

Abstract

A security stay includes a nose cap (6) at the end of a track member (11) for engagement with a nose piece (9) of a locking bar (2). The nose cap (6) comprises a planar steel member of at least 2mm thickness, extending substantially perpendicular to the plane of the track member (1) and orientated at an angle of 20 to 40{ to the transverse direction of the track member (1). The nose cap (6) is capable of flexing under a force applied in the direction of the track member (1). The nose piece (9) includes a reverse locking face (10) orientated to engage on the end of the nose cap (6) in the closed position of the stay and a surface adjoining the locking face having a first portion (12) adjacent to the locking face which is orientated substantially parallel to the opposed face of the nose cap (6) and a second portion (13) which is cut away from the face of the nose cap (6).

Description

SECURITY FRICTION SUPPORTING STAY

Friction supporting stays are used to support windows or doors pivotally in their frames, and generally comprise a track member for mounting on the window or door frame, and a bar for mounting on the window or door, which is pivotally supported from the track by a number of struts which pivot and/or slide along the track. The window or door, when opened, both pivots and moves laterally. The end of the bar generally includes a nose piece, usually triangular in shape, which engages in a mating nose cap at the end of the track. The nose piece may be symmetric, as shown in GB 2247914, or asymmetric as shown in GB 2202271.

The nose piece may be formed separately from plastic or zinc alloy and connected onto the end of the metal bar or it may be integrally formed at the end of the bar, for example by a stamping operation.

GB 2276202 discloses a nose piece having a reverse locking face. This serves to prevent the nose piece migrating out of the nose cap and along the frame when subjected to pressure to pivot the nose piece in a direction opposite to the opening direction. This occurs, for instance, if an attempt is made to force open the window or door from the outside by levering between the edge of the window and the frame with a crow bar. In this document and the commercially available supporting stays made in accordance with this document, the nose cap is formed from relatively thin steel, of about 1mm thickness, but is constructed to withstand compressional forces in both the longitudinal direction of the track member and the transverse direction of the track member. The nose bar is typically formed from steel of approximately 2.5mm thickness. This is necessary to allow the bar to withstand high compressional forces which are generated when the nose bar runs along the face of the nose cap, which occurs if an attempt is made to force the window.

It has been proposed, for instance in GB 2247914, that to increase the strength of the nose cap, the nose cap should be fixed to the frame both in the plane of the track member and in the perpendicular plane. This allows the nose cap to withstand greater forces without failing.

According to the present invention, a security stay for a window or door includes: a track member for mounting in the frame, a bar for mounting on the window or door frame which is pivotally attached to the track member, the bar including a nose piece, a nose cap at the end of the track member for engagement with the nose piece, the nose cap comprising a planar member formed from steel of at least 2mm thickness, extending substantially perpendicular to the plane of the track member and orientated at an angle of 20 to 400 to the transverse direction of the track member, the nose cap being fixed to the track member and the planar member being capable of flexing under a force applied in the direction of the track member, the nose piece including a reverse locking face orientated to engage on the edge of the upright planar member in the closed position of the stay.

When the window is subjected to force in a direction perpendicular to the track member, the bar tends to bend in its middle and as the bar bends, the distance between the ends reduces. If the nose cap is absolutely rigid or fixed to the frame, the nose piece and the locking face move in a direction along the track, until the locking face comes free of the nose cap. Having the nose cap compliant, even only to a small degree ensures that the nose cap can move with the nose piece in the direction along the track with the nose piece, and so keep the locking face in engagement.

The construction of the nose cap enables the nose cap to flex under the initial tensional force as the bar bends, such that the locking face remains in engagement. As long as the locking face remains in engagement, the bar is under tension. In effect, the nose cap and the nose piece act as one when subjected to a force in the direction of the direction of the track member. In prior art nose caps, it has been thought preferable that the nose cap should be attached to the vertical frame member to prevent it from flexing and failing.

In the present invention, the nose cap is constructed to withstand high tensional forces caused when the locking face locks onto the edge of the nose cap and remains in engagement as the nose cap flexes, in contrast to prior art nose caps which have been constructed to withstand compression. The greater thickness of the upright section of the-nose cap prevents it from failing under these tensional forces.

The present inventors have realised that long thin parts are generally more capable of withstanding tensile loads than compression loads, and therefore it is preferable for the bar to remain under tensional forces for as long as possible, as the bar is more likely to fail when subjected to a compressional force. The present invention has allowed much thinner steel material to be used for the bar and also the pivotal struts of the stay, as even quite thin material can withstand high tensile loads.

By not fixing the nose cap to the frame, the hinge does not have to be fitted with the nose cap tight into the corner of the frame. This makes installation of the hinge much easier.

Preferably, the nose piece includes a surface adjoining the locking face having a first portion adjacent

to the locking face which is orientated substantially parallel to the opposed face of the nose cap such chat it engages squarely against the face of the nose cap in the closed position of the stay and a second portion which is cut away from the face of the nose cap.

According to a second aspect of the present invention, a security stay for a window or door includes: a track member for mounting in the frame, a bar for mounting on the window or door frame which is pivotally attached to the track member, the bar including a nose piece, a nose cap at the end of the track member for engagement with the nose piece, the nose cap comprising a planar member, extending substantially perpendicular to the plane of the track member and orientated at an angle of 20 to 400 to the transverse direction of the track member, the nose cap being fixed to the track member and the planar member being capable of flexing under a force applied in the direction of the track member, the nose piece including a reverse locking face orientated to engage on the end of the nose cap in the closed position of the stay and including a surface adjoining the locking face having a first portion adjacent to the locking face which is orientated substantially parallel to the opposed face of the nose cap such that it engages squarely against the face of the nose cap in the closed position of the stay and a second portion which is cut away from the face of the nose cap.

When the window is subjected to force, the bar tends to bend in its middle and as the bar bends, the locking face hooks onto the edge of the nose cap, producing an initial tensional force on the nose cap and the bar. The bending of the bar causes the nose piece to rock in the nose cap and pivot around its corner, causing the locking

face to rock out of engagement with the nose cap. Once the locking face has disengaged, the bar is no longer under tension but is under compression, and is more likely to fail.

The shape of the surface adjoining the locking face and facing the nose cap helps to maintain the locking face in engagement with the nose cap for as long as possible when the stay is subjected to forces which tend to bend the bar. Rather than having a face which is parallel to the face of the nose cap along its entire length, which provides a corner far removed from the locking face around which the nose piece can pivot when the bar starts to bend, the face is cut away such that when the bar bends, the nose piece pivots around a fulcrum much closer to the locking face, allowing the locking face to remain in engagement with the nose cap. The surface may be curved, but preferably is formed from two flat surfaces forming an oblique angled corner.

Preferably, the angle of the nose cap to the transverse direction of the track member is substantially 300. The end face of the nose cap on which the locking face of the nose piece engages is substantially perpendicular to its side faces and is thereby oriented at 20 to 40 , preferably substantially 300, to the longitudinal direction. The locking face is angled at a lesser angle to the longitudinal direction, preferably substantially 20 .

Preferably, the upright planar member has a cut away portion forming the edge on which the locking face engages.

The nose piece is thereby prevented from moving upwards by the portion of the upright planar member above the cut away portion.

Preferably, the end of the nose piece is embossed towards the track member. This lowers the fulcrum point providing increased security.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a side elevation of a stay according to the present invention; Figure 2 shows a plan view of a stay in accordance with the present invention ; Figure 3 shows the nose cap and nose piece in the partly open position ; Figure 4 shows the nose cap and nose piece in the fully closed position ; Figures 5a and 5b show a comparison of a stay in accordance with the present invention and a prior art stay; and, Figure 6 shows a preferred embodiment of a stay in accordance with the present invention.

A security stay includes a track member 1 and a bar 2 arranged to pivot with respect to the track member 1 by means of a number of supporting struts 3a, 3b, 3c, 3d. In the embodiment shown in Figure 1 the back pivot 4 is fixed and the front pivot 5 is a sliding pivot, arranged to slide in the track member 1. A nose cap 6 is fixed at the end of the track member 1 and comprises a bent piece of metal, bent substantially at right angles to the track member 1 and fixed to the track member at fixing points 7. The nose cap 6 is shown in Figure 1 with a plastics cover 8 and is

shown in Figure 2 without the plastics cover. The upright portion of the nose cap 6 is oriented at 300 to the transverse axis of the track member 1, and has a thickness t of at least 2mm, and preferably less than 3. 5mm. The upright portion has a cut away portion 15 around which the nose piece engages. The nose piece 9 is thereby prevented from moving upwards and disengaging from the top of the upright portion.

Figures 3 and 4 show in more detail the relationship and interaction between the nose piece 9 and the nose cap 6. The nose piece 9 has a reverse locking face 10 which, in the closed position abuts to the end face 11 of the nose cap 6. The reverse locking face 10 is oriented at an angle of substantially 200 to the longitudinal axis of the locking bar 2. The face 12 of the nose piece 9 adjacent the reverse locking face 10 lies substantially parallel to the side face of the nose cap in the closed position of the stay. A second surface 13 is angled away from the face 12 to form an oblique angled surface.

The effect of the angled surface formed by faces 12 and 13 is shown in Figures 5a and 5b. In the prior art nose piece as shown in Figure 5a, as a force is applied to bend the bar 2, the nose piece pivots around point 14 causing the reverse locking face 10 to pivot out of engagement with the nose cap 6. In the embodiment of the present invention as shown in Figure 5b, the nose piece 9 pivots about the point 15 where faces 12 and 13 adjoin, which is much closer to the locking face 10 than the point 14 in the prior art nose piece. This enables the locking face 10 to remain in engagement as the bar 2 bends. This means that the bar is maintained under tension for longer and is less likely to fail.

Figure 6 shows an embodiment of the stay in which the nose piece 9 has an end portion 9A which is embossed towards the track member 1. The end portion 9A includes the reverse locking face 10, the face 12 and the surface 13. Because this portion 9A is embossed downwards, it lowers the fulcrum point around which the nose piece 9 pivots on the edge of the nose cap 6. This increases the security of the stay.

Claims

1. A security stay for a window or door including : a track member for mounting in the frame, a bar for mounting on the window or door frame which is pivotally attached to the track member, the bar including a nose piece, a nose cap at the end of the track member for engagement with the nose piece, the nose cap comprising a planar member formed from steel of at least 2mm thickness, extending substantially perpendicular to the plane of the track member and orientated at an angle of 20 to 400 to the transverse direction of the track member, the nose cap being fixed to the track member and the planar member being capable of flexing under a force applied in the direction of the track member, the nose piece including a reverse locking face orientated to engage on the edge of the upright planar member in the closed position of the stay.

2. A security stay according to claim 1, wherein the nose piece includes a surface adjoining the locking face having a first portion adjacent to the locking face which is orientated substantially parallel to the opposed face of the nose cap such that it engages squarely against the face of the nose cap in the closed position of the stay and a second portion which is cut away from the face of the nose cap.

3. A security stay for a window or door including: a track member for mounting in the frame, a bar for mounting on the window or door frame which is pivotally attached to the track member, the bar including a nose piece, a nose cap at the end of the track member for engagement with the nose piece,

the nose cap comprising a planar member, extending substantially perpendicular us the plane of the track member and orientated at an angle of 20 to 400 to the transverse direction of the track member, the nose cap being fixed to the track member and the planar member being capable of flexing under a force applied in the direction of the track member, the nose piece including a reverse locking face orientated to engage on the end of the nose cap in the closed position of the stay and including a surface adjoining the locking face having a first portion adjacent to the locking face which is orientated substantially parallel to the opposed face of the nose cap such that it engages squarely against the face of the nose cap in the closed position of the stay and a second portion which is cut away from the face of the nose cap.

4. A security stay according to any one of the preceding claims, wherein the angle of the nose cap to the transverse direction of the track member is substantially 30 .

5. A security stay according to any one of the preceding claims, wherein the locking face is angled at substantially 20'to the longitudinal direction.

6. A security stay according to any one of the preceding claims, wherein the upright planar member has a cut away portion forming the edge on which the locking face engages.

7. A security stay according to any one of the preceding claims, wherein the end of the nose piece is embossed towards the track member.