GB2337556A

GB2337556A - Shoot bolt mechanism

Info

Publication number: GB2337556A
Application number: GB9811005A
Authority: GB
Inventors: Martin Crawley Franklin
Original assignee: Nico Manufacturing Ltd
Current assignee: Nico Manufacturing Ltd
Priority date: 1998-05-21
Filing date: 1998-05-21
Publication date: 1999-11-24
Also published as: GB9811005D0

Abstract

A shoot bolt mechanism for a door or window comprises an oval track having two opposing parallel sides, two pusher bars 6, (7) slidable along opposing sides of the track, a drive mechanism 4 for driving one of the pusher bars along one side of the track, and thrust transmitting means, e.g. ball bearings, for transmitting thrust around the track to the other pusher bar.

Description

i 1 Shoot Bolt Mechanism 2337556 Shoot bolts are used in doors and windows

to achieve a secure fastening of the door or window at both top and bottom or opposite sides by the operation of a single handle.

A shoot bolt mechanism transmits rotation of the handle into translational movement in opposite directions of two locking bars. Rotation of the handle in one direction causes the locking bars to extend and engage in shoot bolt keeps on opposite ends or sides of the frame of the door or window. Rotation of the handle in the opposite direction retracts the bolts, unlocking the window or door.

The shoot bolt mechanism must be accommodated in the is frame of the window or door and so it is desirable for the mechanism to be as compact as possible. Particularly, extruded UPVC frames are generally of standard dimensions, and these dimensions impose restrictions on the size of the mechanism. Typically, shoot bolt mechanisms comprise rack and pinion arrangements with a reversing mechanism as described in GB 2312236A and GB 2252359A. However. in an attempt to make these mechanisms as small and compact as possible so that they fit into standard frame sections the gears in the reversing mechanisms have to be small with small teeth. In use, if the shoot bolts are not correctly aligned with their keeps and an attempt is made to lock the bolts, then all the locking force applied to a handle has to be absorbed by the teeth of the mechanism. The smaller the teeth the more likely they are to fail. As a result it has been difficult to make the conventional mechanisms both small enough and robust enough at the same time.

According to the present invention, a shoot bolt mechanism for a door or window comprises a generally oval track having two opposing substantially straight parallel sides, two pusher bars each engaging with and slidable along a respective one of the opposing sides of the track, a coupling on each pusher bar for engagement with a locking 2 r, bar, a drive mechanism capable of being operated by rotation of a handle for driving one of the pusher bars forwards or backwards along one side of the track, and thrust transmitting means for transmitting thrust around the track to cause a reciprocal movement of the other pusher bar backwards or forwards along the opposite side of the track, in use, to move locking bars in opposite directions.

Preferably, the oval track lies generally in a plane perpendicular to the axis of rotation of the handle. However it is also possible to have the oval track arranged in a plane inclined to the axis of rotation of the handle. By doing this it is possible to make the ends of the track with greater radius of curvature whilst still minimising the width of the mechanism, and still allowing it to fit into narrow frames.

Preferably, the thrust transmitting means comprises ball bearings matched to the width of the track and arranged to fill the portions of the track not occupied by the pusher bars. Possible alternative means of transmitting thrust from the driven pusher bar to the reciprocating pusher bar comprise a helical coil spring with touching adjacent turns, or cylindrical members having rounded ends arranged in the track to fill the portions of the track not occupied by the pusher bars and to slide along the track, operating similarly to the ball bearings. However, steel ball bearings are cheaper and more readily available and hence are preferred.

The rotation of the handle may be transmitted to the drive mechanism by means of a square shaft which engages in a square aperture of the drive mechanism. The drive mechanism may comprise a circular member rotatably mounted in the body of the shoot bolt mechanism having an arm for engaging with a recess in the driven pusher bar. Alternatively, the drive mechanism may comprise a drive pinion which is rotatably mounted in the body of the shoot 3 bolt mechanism and rotatable by the handle to engage with a rack formed on the driven pusher bar.

The present invention will now be described in accordance with the accompanying drawings in which:- Figure 1 is a partly sectioned side elevation of a first embodiment; Figure 2 is a plan of the lower part of the mechanism shown in Figure 1; Figure 3 is a cross section drawn to a larger scale taken through the operating mechanism; Figure 4 is a plan of a typical arrangement of locking bars; Figure 5 is a partly sectioned of a side elevation second embodiment; Figure 6 is a plan of the lower part of the mechanism shown in Figure 5; and, Figure 7 is a cross section through the operating mechanism of the second example.

A shoot bolt mechanism comprises a generally oval track 8 having two parallel opposite substantially straight sides. Two pusher bars 6, 7 are slidably mounted in the track 8, such that each pusher bar is moveable along one of the opposite sides of the track 8. The portion of the track 8 which is not occupied by the pusher bars 6, 7 is filled with ball bearings 9, each of which has a diameter slightly less than the width of the track 8 so that they roll readily around the track. The length of the pusher bars 6,7 is such that an exact number of ball bearings fit into the remaining area of track and there are substantially no gaps between the ball bearings 9. With such an arrangement, when one of the pusher bars 6,7 is moved in one direction along one side of the track, the ball bearings transmit the thrust around the track to the other pusher bar which moves in the opposite direction along the opposite, parallel side of the track.

A generally circular member 2, rotatably mounted in the body 1 of the shoot bolt mechanism, has a central 4 square recess 3 to receive a square shaft of a handle. on rotation of the handle, the circular member 2 rotates, and an arm 4 formed on the circular member engages with a recess 5 in the driven pusher bar 6 causing the driven pusher bar 6 to move in a first direction A along its side of the track. This causes a reciprocal movement of a second pusher bar 7 which moves in a direction B opposite to A. Protrusions 14,15 on the pusher bars 6,7 engage with recesses in the locking bars 10,11 which slide in opposite directions to lock into shoot bolt keeps on opposite sides of the outside frame. The hand of the mechanism depends on the relative position of the protrusions 14,15 on the respective pusher bars. In the embodiment of figures 1 to 3, the mechanism is left handed ie the locking bars are is extended by an anti clockwise rotation of the handle and retracted by a clockwise rotation. If the protrusions are located at the other ends of the pusher bars as in the embodiment shown in figures 5 to 7, the mechanism is right handed ie the locking bars are extended by a clockwise rotation of the handle and retracted by an anti clockwise rotation. Figure 4 shows an arrangement of locking bars which interact with a right handed mechanism. Recesses 12,13 in the locking bars interact with protrusions 14,15 of the pusher bars 6,7.

The two sides of the oval track need not be at the same level. In Figure 3, the driven pusher 6 runs in a shallower track than the reciprocating pusher 7. This enables the ends of the tracks to have a larger radius of curvature whilst the entire mechanism still has a relatively narrow width.

Figure 5 shows a second embodiment of the invention wherein the drive mechanism comprises a drive pinion 104 having a central square aperture 103 for receiving a square shaft of a handle. When the handle is rotated the square shaft transmits the rotation to the drive pinion 104 which rotates and engages with a toothed rack 105 on the under side of the driven pusher 106. As described with reference to the first embodiment, the driven pusher slides along the straight side of the oval track, and the thrust is transmitted by ball bearings 109 to cause a reciprocal movement of the second pusher 107 in the opposite direction along the other side of the track. The reciprocating movement of the two pusher bars 106,107 operates locking bars which move in opposite directions to engage with shoot bolt keeps on opposite sides of a window or door frame.

The embodiments in accordance with this invention are both robust and accommodate the substantial forces generated by, for example, someone strongly turning the handle to try and lock the shoot bolts when their ends are not in alignment with their keeps. Also they are compact, particularly in the width-wise directions so that they fit in a standard "Eurogroove" in a frame.

c 6

Claims

1 - A shoot bolt mechanism f or a door or window comprising a generally oval track having two opposing substantially straight parallel sides, two pusher bars each engaging with and slidable along a respective one of the opposing sides of the track, a coupling on each pusher bar for engagement with a locking bar, a drive mechanism capable of being operated by rotation of a handle f or driving one of the pusher bars forwards or backwards along one side of the track, and thrust transmitting means for transmitting thrust around the track to cause a reciprocal movement of the other pusher bar backwards or forwards along the opposite side of the track, in use, to move locking bars in opposite directions.

2. A shoot bolt mechanism according to claim 1, wherein the oval track lies generally in a plane perpendicular to the axis of rotation of the handle.

3. A shoot bolt mechanism according to claim 1, wherein the oval track lies generally in a plane inclined to the axis of rotation of the handle.

4. A shoot bolt mechanism according to any of the preceding claims wherein the thrust transmitting means comprises ball bearings matched to the width of the track and arranged to fill the portions of the track not occupied by the pusher bars.

5. A shoot bolt mechanism according to any one of claims 1 to 3 wherein the thrust transmitting means comprises a helical coil spring with touching adjacent turns.

6. A shoot bolt mechanism according to any one of claims 1 to 3 wherein the thrust transmitting means comprises cylindrical members having rounded ends arranged in the 7 track to fill the portions of the track not occupied by the pusher bars.

7. A shoot bolt mechanism according to any one of the preceding claims wherein the rotation of the handle is transmitted to the drive mechanism by means of a square shaft which engages in a square aperture of the drive mechanism.

8. A shoot bolt mechanism according to any one of the preceding claims wherein the drive mechanism comprises a circular member rotatably mounted in the body of the shoot bolt mechanism having an arm for engaging with a recess in the driven pusher bar.

9. A shoot bolt mechanism according to any one of claims 1 to 7 wherein the drive mechanism comprises a drive pinion which is rotatably mounted in the body of the shoot bolt mechanism and rotatable' by the handle to engage with a rack formed on the driven pusher bar.

1.

1 10. A shoot bolt mechanism substantially as described herein or shown in the accompanying drawings.