GB2223795A - Security fittings - Google Patents

Abstract

The security fitting for a window has a fastening assembly 1 and a keep plate 2, respectively mounted on the fixed frame 3 and moving frame 7. The assembly 1 comprises a body 6 bearing a rotatable shaft 11 with a cross-pin 13 at one end. An actuating button 15 borne slidably in the body 6 surrounds the shaft 11 and is pressed by a spring 19 against the pin 13. The spring 19 also applies a torsional bias to the shaft 11 but the shaft is held against the bias in the unfastened condition (Fig. 2), by the pin 13 lying in a slot 17 in the button 15. When the window is closed the keep plate 2 comes up against the button 15 and presses the latter into a well 16 in the body 6, thereby releasing the shaft 13 to turn under the bias of the spring 19 into a position in which the pin 13 lies in a recess 25 and cannot be withdrawn from the keep plate (Fig. 3). Unfastening is achieved by a key (29, Figure 7) engaging the head 12 of the shaft to turn back the pin 13, the compressed spring 19 acting through the button 15 to assist opening of the window. <IMAGE>

Description

Security Fittinqs The present invention relates to security fittings and in particular is concerned with a locking device for securing a hinged window closed to its frame, although fittings in accordance with the invention may also find utility in the locking together of other similarly movable members. It is an aim of the invention to provide a simple and effective fitting of this character adapted to become locked automatically upon closure of the window. Still more particularly the invention seeks to provide in a preferred embodiment a fitting structurally similar to and adapted for the same service as the fitting described in our United Kingdom patent specification no. 2082243 - but adapted for automatic instead of manual locking operation.

In one aspect the invention accordingly resides in a security fitting comprising a lock assembly and a keep member which in the locking condition of the fitting interengage to prevent relative displacement thereof in a predetermined sense of direction; the lock assembly comprising a lock body bearing a rotatable locking member which is biased towards a first rotary position thereof and a linearly movable actuating member which is biased towards a first axial position thereof; in the unlocking condition of the fitting said actuating member lying in its said first axial position in which it retains the locking member in a second rotary position away from its said first rotary position; the keep member being configured such that when brought into operative juxtaposition with the lock assembly by relative movement in the sense of direction opposite to said predetermined sense a portion thereof engages a portion of said actuating member to displace the latter away from its first axial position, thereby releasing the locking member to move into its first rotary position under its said bias in which position it interengages with the keep member to prevent relative displacement thereof as aforesaid; and the lock assembly further comprising key-engageable means whereby the locking member can be returned from its first to its second rotary position, thereby to unlock the fitting.

In a preferred embodiment the locking member comprises a lateral projection provided at one end of a rotatable shaft borne by the lock body, the opposite end of the shaft having a key-engageable formation, and the actuating member is borne around and coaxial with said shaft to slide into a recess within the lock body, away from said one end of the shaft, to release the locking member as aforesaid when engaged by the keep member.

Preferably also the locking member and the actuating member are biased to their respective first said positions by means of a common coil spring acting between these two members and loaded both compressively and torsionally.

A particularly preferred embodiment of a security fitting in accordance with the invention will now be more fully described, by way of example, with reference to the accompanying drawings in which: -Figure 1 is a plan view of the fitting as shown in use to lock a hinged window; Figure 2 is a vertical section through the lock assembly of the fitting in the unlocked condition; Figure 3 is a vertical section through the lock assembly and keep plate of the fitting in the locked condition; Figure 4 is a front view of the lock assembly; Figure 5 is a front view of the keep plate; Figure 6 is a rear view of the keep plate with the fitting in the locked condition; and Figure 7 illustrates a key suitable for unlocking the fitting.

The illustrated fitting comprises a lock assembly 1 and a keep plate 2, the two parts being intended for mounting on a hinged window as shown in Figure 1. That is to say the lock assembly 1 is mounted to the fixed frame 3 of a window, remote from the hinge line, by means of screws 4 passing through holes 5 (Figs 2 & 3) in the body 6 of the assembly, while the keep plate 2 is mounted to the moving frame 7 (of which the direction of opening and closing is shown by the arrow A in Figure 1) by means of screws 8 passing through holes 9 (Fig 5) in the plate. The parts are so located that the front face of the keep plate comes into register with the rear face of the body 6 when the window is closed.For mounting on windows with tapered fixed frames such as shown in Figure 1 a packing piece 10 will be used between the side of the body 6 and the frame to ensure correct alignment although no such expedient is required when the surface of the fixed frame is normal to that of the moving frame.

Turning to Figure 2, the lock assembly 1 includes a rotatable shaft 11 having an enlarged head 12 at one end and carrying a cross-pin 13 at the opposite end. This shaft is journalled in the body 6 at its head end and retained by a circlip 14, the end carrying the cross-pin 13 extending out of the confines of the body 6 and beyond its rear face as shown in Figure 2. A cup-shaped actuating button 15 of generally rectangular transverse cross-section surrounds the shaft 11 and is borne slidably, but non-rotatably, by a central well 16 of the body 6. This button has a vertical (in the sense of the drawings) slot 17 at its rear end, in which the cross-pin 13 is retained in the unlocked condition of the assembly shown in Figure 2, and one part of one flanking wall of this slot is extended rearwardly as indicated at 18.

The button 15 is biased rearwardly against the cross-pin 13 by a coil spring 19, which also applies a torsional bias to the shaft 11 tending to rotate it in the anticlockwise sense as viewed from the rear of the assembly and in Figure 6. To this end the spring 19 has a radially inturned tail 20 at one end which is received in a radial slot 21 in the shaft and has a longitudinally- extending tail 22 at the other end which is received in a hole offset from the slot 17 in the end face of the button 15, the spring being suitably prestressed both compressively and torsionally on the assembly of these components to apply the indicated biases. In the illustrated unlocked condition, however, the shaft 11 is held away from the position to which it is biased by virtue of the engagement of its cross-pin 13 in the slot 17 of the button 15.

The keep plate 2, seen in Figures 3, 5 and 6, has a front flange 23 with an aperture 24 of the form shown in Figure 5, which has a height sufficient to pass the cross-pin 13 of the lock assembly when in its vertical orientation but a width which will not pass the cross-pin 13 when turned through a significant angle away from that orientation.

Rearwardly, however, this aperture opens up into a wider recess as indicated at 25 in Figure 6.

Operation of the illustrated fitting to lock the window occurs automatically on closing the latter, the locked condition of the fitting being as shown in Figures 3 and 6. As the keep plate 2 carried by the moving frame 7 approaches the rear of the assembly 1 portions of its flange 23 at the margins of the aperture 24 engage registering parts of the rear face of the button 15 and press the latter into the well 16 against the compressive bias of the spring 19. The projecting flank 18 of the button is, however, accommodated within the keep plate aperture 24. As the button moves in the cross-pin 13 is released from the slot 17 but is still held in the vertical position against the torsional bias of the spring 19 by its engagement with the button flank 18, until the keep plate has been brought to the position in which its aperture 24 has passed the cross-pin 13.At this point the flank 18 clears the pin 13 and the shaft 11 is therefore freed to rotate under its bias and turn the cross-pin 13 to the locking condition of Figures 3 and 6 in which it lies in the recess 25 behind the flange 23 to block withdrawal of the keep plate.

To unlock the fitting from this condition it is necessary to rotate the shaft 11 back to the position in which the cross-pin 13 is vertical. For this purpose the head 12 is provided with a formation engageable by a complementary key to impart the necessary rotation to the shaft. This may take various forms but in the illustrated embodiment the head 12 has an annular groove 26 the inner face of which is formed to provide a ramp surface 27 leading to a radial shoulder 28. This is adapted to be operated by a key 29 as shown in Figure 7, which terminates in a annular bit of complementary form having a ramp surface 30 and a radial shoulder 31.With this bit inserted into the groove 26 the shoulders 31 and 28 are engageable to transmit torque from the key 29 to the shaft 11 in the correct sense (anticlockwise as viewed in Figure 4) to return the cross-pin 13 from its locking to its unlocking position, but if the key is turned in the incorrect sense the ramp surface 30 of the key will simply slip over the ramp surface 27 of the shaft and will have no effect on the fitting.

Once the cross-pin 13 is returned to its vertical orientation the keep plate 2 can pass back over it as the window is opened. It will be appreciated that the compressed spring 19 acts through the button in the direction to urge the window open and (if otherwise unrestricted) will assist in ejecting the keep plate as soon as the cross-pin 13 is turned back past the margins of the keep plate aperture 24 and has passed across the end face of the projecting flank 18. As soon as the button 15 begins to move back out of the well 16 the flank 18 will intercept the cross-pin 13 to keep it in the vertical position against the torsional bias of the spring 19 until finally received within the slot 17. The presence of the flank 18 in this respect is important in ensuring that the cross-pin does not spring back out of alignment with the slot 17 when the key is released, particularly in the (albeit unlikely) event that the person unlocking the window opens it away from the assembly 1 at a faster rate than the movement of the button 15.

Claims (5)

1. A security fitting comprising a lock assembly and a keep member which in the locking condition of the fitting interengage to prevent relative displacement thereof in a predetermined sense of direction; the lock assembly comprising a lock body bearing a rotatable locking member which is biased towards a first rotary position thereof and a linearly movable actuating member which is biased towards a first axial position thereof; in the unlocking condition of the fitting said actuating member lying in its said first axial position in which it retains the locking member in a second rotary position away from its said first rotary position; the keep member being configured such that when brought into operative juxtaposition with the lock assembly by relative movement in the sense of direction opposite to said predetermined sense a portion thereof engages a portion of said actuating member to displace the latter away from its first axial position, thereby releasing the locking member to move into its first rotary position under its said bias in which position it interengages with the keep member to prevent relative displacement thereof as aforesaid; and the lock assembly further comprising key-engageable means whereby the locking member can be returned from its first to its second rotary position, thereby to unlock the fitting.

2. A security fitting according to claim 1 wherein the locking member comprises a lateral projection provided at one end of a rotatable shaft borne by the lock body, the opposite end of the shaft having a key-engageable formation, and the actuating member is borne around and coaxial with said shaft to slide into a recess within the lock body, away from said one end of the shaft, to release the locking member as aforesaid when engaged by the keep member.

3. A security fitting according to claim 1 or claim 2 wherein the locking member and the actuating member are biased to their respective first said positions by means of a common coil spring acting between said two members and loaded both compressively and torsionally.

4. A security fitting comprising a lock assembly and a keep member which in the locking condition of the fitting interengage to prevent displacement of the one away from the other; the lock assembly comprising a lock body bearing a rotatable shaft; the shaft having a keyo engageable formation accessible at a front face of the lock body and the shaft extending rearwardly beyond a rear face of the lock body and carrying there a lateral projection; an actuating member borne slidably but nonrotatably by the lock body, coaxial with and surrounding the shaft; spring means acting between the shaft and the actuating member whereby to press the actuating member rearwardly against said lateral projection and to bias the shaft in a predetermined sense of rotation; the actuating member having an abutment portion at a rear face thereof by which said lateral projection is held in a predetermined rotary position against the rotational bias applied to the shaft, in the unlocking condition of the fitting; and the keep member having a front face through which opens an aperture configured to pass the lateral projection when in its said predetermined rotary position but not to pass said projection when turned away from that position; whereby when the front face of the keep member is brought towards the rear face of the lock body a portion thereof engages the actuaring member to press the same inwardly through the rear face of the lock body as said lateral projection passes through said aperture, the consequent release of the lateral projection by said abutment portion of the actuating member permitting the same to turn under the rotational bias applied to the shaft into a position in which said aperture will not pass the same.

5. A security fitting substantially as hereinbefore described with reference to the accompanying drawings.