GB2413822A

GB2413822A - Lock mechanism locked by a pivoting deadbolt

Info

Publication number: GB2413822A
Application number: GB0410262A
Authority: GB
Inventors: Bernard Viney
Original assignee: Surelock McGill Ltd
Current assignee: Surelock McGill Ltd
Priority date: 2004-05-07
Filing date: 2004-05-07
Publication date: 2005-11-09
Anticipated expiration: 2024-05-07
Also published as: GB2413822B; GB0410262D0

Abstract

A lock mechanism is disclosed which comprises a bolt member 10 and a deadbolt 22 rotatable about a pivot 24 between a locked position in which movement of the bolt member 10 is inhibited and an unlocked position. An inner driving mechanism 28, such as a key cylinder, is at least partially located within an aperture through the deadbolt member 22. Various features disposed around the periphery of the rotating deadbolt 22 allow it to interact with interchangeable components of the surrounding lock mechanism. The mechanism may further comprise an outer driving mechanism 28, which may comprise an electrical solenoid. The lock mechanism may also comprise one or more microswitches 34 to sense a position of the deadbolt. The lock mechanism may also comprise a shoot bolt mechanism, which may comprise a drive pinion 12 and a slave pinion 14.

Description

LOCK MECHANISM

The present invention relates to a lock mechanism having a rotating or pivoting deadbolt element, and in particular, but not exclusively, to such a lock mechanism in which a broadly planar egg shaped or pear shaped deadbolt element pivoted at the narrower end is driven by a driving mechanism such as a key cylinder at least partly located within or having an axis of rotation extending through a central cut-out or aperture of the deadbolt element.

A prior art bolting mechanism incorporating a deadbolt mechanism is disclosed in GB6478345. The bolting mechanism incorporates bolt member pushrods extending upwards, downwards and laterally. The pushrods are moveable by a common driving mechanism of gears, between disengaged and engaged positions, so as to secure a leaf, such as a door or window, within a frame.

The upwardly extending pushrod is provided with a tang which may be blocked by a horizontally sliding deadbolt driven by the rotating cam of a key cylinder, so as to retain the pushrod in either the engaged or disengaged position.

The deadbolt mechanism of GB6478345 is relatively inflexible in that it is difficult to change the way in which the deadbolt is driven and biased without making major changes to the layout of the mechanism. However, different security situations may dictate very different lock mechanism requirements. For example, a deadbolt biased towards the locked position or the unlocked position, retention of the key when unlocked or key release when unlocked, electrical driving of the deadbolt with a locked or unlocked bias and with or without manual key driven - 2 override, and a host of other features may be required. It would be desirable to provide a deadbolt lock mechanism in which a variety of different combinations of driving mechanisms, bias arrangements and so on can easily be provided without extensive changes to the layout and basic components of the mechanism.

Furthermore, a sliding deadbolt such as that disclosed in GB6478345 may be subject to a malleting attack in which heavy pressure applied to the bolt member at the same time as repeated vibration, for example by hammering close to the lock casing, can cause the deadbolt to unlock. In GB6478345 such an attack is prevented by use of an extra latch, but this adds complexity and cost. Such an attack can also be prevented by using a sufficiently heavy bias spring or detent on the deadbolt, but this can make the action of the lock undesirably heavy.

The invention addresses problems and disadvantages in the related prior art. In particular, the invention provides a lock mechanism comprising a bolt member moveable between an engaged position and a disengaged position; and a deadbolt rotatable about a pivot between a locked position in which movement of the bolt member is inhibited, and an unlocked position. Using such an arrangement a lighter lock action can be achieved, without compromising resilience to a malleting attack.

The bolt member may itself terminate in a bolt tip which acts to prevent relative movement between two elements, such as a door and a frame, when in an engaged position. Alternatively, the bolt member may be a pushrod or some other intermediate element. Rotation of the deadbolt about a pivot rather than a linear sliding movement of the deadbolt allows for a smoother and lighter lock action, and provides more opportunities to develop a flexible lock mechanism layout.

Typically, the bolt member will be moveable along a bolt axis between the engaged and disengaged positions.

Preferably, the axis of rotation of the deadbolt about the pivot is spaced from and substantially perpendicular to the bolt axis.

In a preferred embodiment the deadbolt comprises a pivot portion with two arms extending approximately radially therefrom. An arcuate portion of the deadbolt extends between the ends of the arms distal from the pivoted portion, so as to define an aperture or cut-out in the centre of the deadbolt and to complete the circumference of the roughly egg shaped or pear shaped planar deadbolt with the pivot portion and associated pivot at the narrow end.

One end of the arcuate portion defines a deadlock head portion which, on pivoting of the deadbolt, engages with or disengages from one or more locking recesses in the bolt member to provide the locking action.

The deadbolt, and in particular the above mentioned head portion of the deadbolt, preferably presents one or two deadlock surfaces arranged to be in confrontation with corresponding surfaces of the bolt member when the bolt member is in the engaged and disengaged positions and the deadbolt is in the locked position. Preferably, the deadlock surfaces are substantially perpendicular to a radius extending therefrom to the deadbolt pivot.

The deadbolt may be pressed, cast or machined, typically from steel or another metal, with a suitable thickness or depth.

Using the above or other deadbolt layouts, the deadbolt may be provided with a through aperture, the lock mechanism - 4 further comprising an inner driving mechanism arranged to drive the deadbolt between the locked and unlocked positions, the inner driving mechanism being at least partly located within, and preferably passing through the aperture.

To enable the inner driving mechanism to drive the deadbolt, the boundary of the deadbolt aperture, typically towards the centre of the arcuate portion, may comprise a major slot, and the inner driving mechanism may then comprise one or more rotating cams adapted to engage the major slot so as to drive the deadbolt between the locked and unlocked positions.

In some embodiments, the one or more rotating cams are driven by one or more corresponding profile type key cylinders located partly within or adjacent to the deadbolt aperture, and/or having an axis of rotation passing through the aperture.

In other embodiments, the inner driving mechanism comprises at least one ramming boss carrying one of said rotating cams, said ramming boss being provided with a central slot for accepting a key cylinder tang and one or more turnknob connection features for the connection of a turnknob. Using such an arrangement, the deadbolt may be driven from either side by either a rim type key cylinder or a turnknob.

Such an arrangment may be put into effect by constructing the loner driving mechanism using two similar or identical camming bosses facing in opposite directions, but having a common axis of rotation passing though the deadbolt aperture. A core boss is located between the ramming bosses, the core boss being provided with a further rotating cam and one or more turnknob locking features for securing a turoknob connected though the turnknob connection features, typically two through holes, of one of the Hamming bosses.

Preferably, the boundary of the deadbolt aperture comprises a minor slot located within the major slot, the mechanism being arranged such that the further rotating cam of the core boss is engaged within the minor slot so as to drive the deadbolt between the locked and unlocked positions on rotation of a turnknob.

In addition or alternative to the inner driving mechanisms described above, the lock mechanism may comprise an external driving mechanism not located within the deadbolt aperture. In preferred embodiments, this external driving mechanism is an electrical solenoid, which may be provided with a mechanical bias arranged to urge the deadbolt towards one of the locked and unlocked positions.

The external driving mechanism may be conveniently located adjacent to the arcuate portion of the deadbolt.

The external driving mechanism may conveniently act on the deadbolt by means of engagement with a external driving slot in the periphery of the deadbolt, such as in the outer edge of the arcuate portion.

The deadbolt is preferably provided with a bias spring hook, and in certain configurations a bias spring is coupled to the bias spring hook so as to urge deadbolt towards a selected one of the locked and unlocked positions.

The deadbolt is also preferably provided with a detent surface comprising one or more detent minima. The detent surface may conveniently be located at the outer edge of the arcuate portion of the deadbolt, distal from the deadbolt pivot. In certain configurations the lock mechanism further comprises a detent spring acting upon the detent surface and favouring the detent minima so as to tend to selectively - 6 hold the deadbolt in particular positions, such as the locked and unlocked positions.

The lock mechanism may further comprise one or more electrical position sensors to detect the position of the deadbolt. In particular, one or more microswitches may be used, each microswitch having a switch arm bearing upon the deadbolt so as to sense a position of the deadbolt.

Conveniently, sensing parts of the position sensor or sensors, for example the above mentioned switch arm or arms, may bear upon an edge surface of the deadbolt proximal to the pivot, where the relatively large arcuate movement of the distal end of the deadbolt is translated into a relatively small movement suitable for detection by an electrical switch arrangement.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings of which: Figure 1 shows a three point bolting mechanism comprising a lock mechanism embodying the present invention; Figure 2 is an enlarged view of the lock mechanism of figure 1, showing a rotatable deadbolt but omitting various ancillary devices and mechanisms so as to illustrate the basic locking action; Figure 3a is as figure 2, but showing the deadbolt rotated into a locked position so as to hold the bolting member in an engaged position; Figure 3b is as figure 3a, but showing the bolting member held in a disengaged position; Figure 4 shows the lock mechanism of figure 2 with additional mechanisms including electrical solenoid and profile type key cylinder driving mechanisms; Figure 5 shows the same arrangement as figure 4, but with the electrical solenoid removed and a detent spring added; Figure 6 shows the same arrangement as in figure 5, but with the deadbolt in an unlocked position and with cam block elements preventing further rotation in and consequently removal of the key from the profile type key cylinder; Figure 7 shows the lock mechanism of figure 2 arranged to be driven by cams driven by a rim cylinder(s) and/or a turnknob(s), with the deadbolt being biased towards the locked position by a bias spring.

Referring now to figure 1 there is shown a bolting mechanism 5 having three bolt members 8, 9, 10 extending in horizontal and vertical directions. The bolt members are driven by a common bolting mechanism comprising a driving pinion 12 and a slave pinion 14 acting on racks formed into the proximal ends of the bolt members. The distal end of each bolt member will typically be expendable from a leaf to engage with an aperture in a frame to thereby secure the leaf within the frame when the bolts are moved from the disengaged position to the engaged positions. Each bolt member may comprise, for example, a push rod connected to a bolting tip, or any similar arrangement.

Each bolt member is generally movable along a sliding axis. The movement of at least one of the bolt members is restricted by means of a deadbolt mechanism 20 comprising a rotatable deadbolt element 22, hereinafter referred to as the deadbolt, which rotates about a pivot 24 such that a head portion 26 of the deadbolt engages or releases the bolt member. The general configuration of the deadbolt 22 is such as to allow a variety of different ancillary devices and mechanisms to be used in conjunction with the deadbolt. - 8

Various example mechanisms are shown in broken lines, Including inside and outside driving mechanisms 28, detent means 30, bias means 32 and a position sensor 34.

The rotating motion of the deadbolt about its pivot, the rotating motions of the slave and driving pinions and the linear motions of the bolt members are shown in heavy arrows.

Referring now to figure 2 there is shown a deadbolt mechanism suitable for use in the arrangement of figure 1, but omitting the various ancillary devices and mechanisms mentioned so as to illustrate the basic locking action and deadbolt movement. The particular deadbolt illustrated in figure 2 is essentially planar and shaped like an inverted pear or egg, with a pivot portion 40 located at the lower, narrow end. Two arms 42, 44 extend approximately radially away from the pivot portion to meet a broad arcuate portion 46 which is terminated at one end by the head portion 26 and completes the deadbolt to define a central cut-out or aperture 48.

The deadbolt is pivoted at the lower, narrow end pivot portion 40 on deadbolt pivot 50 the axis of which is spaced from and approximately perpendicular to the axis of linear movement 52 of the adjacent bolt member 10. The bolt member 10, which is moveable in the direction indicated by the heavy arrow thereon, includes two roughly rectangular locking recesses, the first being a larger major locking recess 54 and the second being a smaller minor locking recess 56. Rotation of the deadbolt about the pivot 50 allows the head portion 26 to engage either the major locking recess 54 or the minor locking recess 56 to secure the bolt member 10 either in the engaged or the disengaged position respectively.

The deadbolt element 22 itself is formed as a frame, with a large central aperture 48. The aperture reduces the weight and the material required to form the deadbolt, while retaining the advantages of a broad pear or egg shaped deadbolt in terms of strength and convenience for fitting a range of different ancillary mechanisms. The central aperture also provides a convenient location for locating ancillary mechanisms such as one or more driving mechanisms.

The rotational movement of the deadbolt 22 is limited by two deadbolt stop lugs 60, 62 which act against corresponding pillars 64, 66 which may additionally have other functions. In figure 2 the deadbolt 22 is shown in an intermediate location between the two possible extremes of rotation. The deadbolt mechanism 20, including the pivoted deadbolt 22 and various ancillary mechanisms not illustrated in figure 2 may be mounted upon a back-plate or frame 68 forming a part of or connected to the frame or casing of the larger bolting mechanism 5.

Figure 3a shows the same elements as figure 2, but with the deadbolt 22 rotated to its limit of movement in an anti- clockwise sense, and with the bolt member 10 in the engaged position. The head portion 26 is thus shown partly located within the major locking recess 54 of the bolt member 10.

The head portion 26 of the deadbolt includes upper and lower deadbolt locking surfaces 70, 72, each locking surface being substantially perpendicular to a radius extending from the surface to the deadbolt pivot 50. In the configuration of figure 3a, the upper deadbolt locking surface 70 is in confrontation with a corresponding obliquely truncated upper corner surface 74 of the major locking recess 54. The oblique upper corner surface 74 is also substantially perpendicular to a radius extending to the deadbolt pivot 50, when the bolt member 10 is in the engaged position.

It will be seen that the space provided by the larger major locking recess allows a small amount of movement of the head portion 26 further towards the locked direction.

If the bolt member is put under pressure to move towards the disengaged position, for example during an attempted breach of the bolting mechanism, slight deformations and play between the bolt member 10 and the deadbolt 22, in conjunction with the recess provided, allow the deadbolt 22 to engage more securely without requiring a heavy sprung bias in that direction.

Figure 3b is similar to figure 3a, except that the bolt member 10 is now in the disengaged position. Motion of the bolt member 10 towards the engaged position is prevented by confrontation between the lower deadbolt locking surface 74 and a hooked lower corner surface 76 of the minor locking recess 56.

Figure 4 shows how the mechanism of figure 2 may be complemented by various ancillary mechanisms. The mechanisms shown in figure 4 include an outer driving mechanism in the form of an electrical solenoid 80 mounted above the deadbolt. The solenoid 80 acts through a coupling plate 82 which engages an outer driving slot 84 located in the wide upper edge of the arcuate portion 46 of the deadbolt 22, adjacent to the head portion 26. The solenoid is mounted such that the central core 86 is driven in a direction perpendicular to the direction of movement of the bolt member 10, thereby enabling the solenoid to drive the deadbolt between the locked and unlocked positions. A solenoid bias spring 88, shown compressed, serves to bias the solenoid core towards locking or unlocking the deadbolt.

In the figure, this spring drives the deadbolt towards the locked position.

A second driving mechanism is provided in the form of one single or double sided, or two profile type key cylinders 90 located on one or both sides of the lock mechanism and extending into the deadbolt aperture 48. The or each profile type key cylinder 90 includes a driving cam 92 arranged to engage within a major slot 94 in the broader upper periphery of the deadbolt aperture 48. The rotatable key cylinder driving cam 92 is shown in broken lines in a number of alternative positions, which will be discussed below. Not all of the positions correspond suitably to the position of the deadbolt 22 as illustrated.

The key cylinder 90 is retained in position by a key cylinder fixing screw 100 which also engages with the frame 68. The head of the fixing screw 100 is conveniently located to allow easy access to release and change the profile type key cylinder. The one or two profile type key cylinders will usually allow key removal in one rotational position only, so that key insertion and removal can thereby be controlled according to the lock state, by shaping the deadbolt and other surfaces appropriately.

The position of the deadbolt 22 may be sensed by one or more microswitch position sensors 104 mounted to the frame 68, each position sensor having a microswitch arm 106 which bears upon a suitable position sensor abutment surface 108 of the deadbolt 22. In the configuration shown in figure 4, the position sensor abutment surface 108 is formed by a suitable surface of the deadbolt stop lug 62 which limits travel of the deadbolt in the clockwise direction, towards the unlocked position. More than one position sensor 104 - 12 may be provided, for example to provide sensing of several different positions of the deadbolt 22.

Operation of the deadbolt mechanism as shown in figure 4 will now be discussed, with reference to a number of different positions of the key cylinder driving cam 92 labelled a, b, c and d in the figure. When the cam is in position a, the key may be removed from or inserted into the key cylinder. The deadbolt 22 will be in the locked position, anti-clockwise of the position actually shown in figure 4, and the solenoid will be unpowered, with the solenoid bias spring 88 urging the coupling plate 82 and hence the deadbolt 22 into the locked position.

With the deadbolt in the locked position, insertion of a key into the key cylinder 90 will allow rotation of the driving cam 92 from position a through to position b, so as to engage one side of the major slot 94. Continued clockwise rotation of the key cylinder driving cam will then urge the deadbolt in a clockwise direction towards the unlocked position, against the action of the solenoid bias spring 88. The solenoid remains unpowered. The limited travel allowed by the solenoid prevents the key cylinder driving cam 92 from rotating further than position c, so that the key is retained in the key cylinder unless turned again in an anticlockwise direction, thereby allowing the solenoid bias spring 88 to urge the deadbolt 22 back towards the locked position.

Rotation of the key cylinder cam 92 in an anti- clockwise sense from position a to position d brings the cam into confrontation with a locking abutment 95 on the inside edge of the arcuate portion 46 of the deadbolt, further from the head portion 26 than the major slot 94. If the solenoid is currently powered, urging the deadbolt towards the unlocked position, then by rotating the key cylinder cam 92 to position d, the deadbolt can be urged towards the locked position against the action of the solenoid 80.

Referring now to figure 5 there is shown a configuration of the deadbolt mechanism shown in figure 2 which includes the key cylinder 90 and position sensors 104 of figure 4, but omits the solenoid 80. A detent spring 120 is shown acting upon the upper, outer edge of the arcuate portion 46 of the deadbolt 22. A portion of the detent spring presses down into either of two detent recesses 122, 124 formed in the deadbolt, so as to tend to hold the deadbolt 22 in either the locked or the unlocked position.

A central portion of the detent spring 120 is wrapped around a first spring pillar 126 which thereby acts as a fulcrum, with the end of the detent spring distal from the detent recesses bearing upon a second spring pillar 128.

Without a solenoid driving mechanism limiting the travel of the deadbolt 22, the deadbolt is enabled to move fully between the extreme locked and unlocked positions represented by the interaction between the deadbolt stop lugs 60, 62 and the pillars 64, 66. The key cylinder driving cam 92 is shown in four different positions marked a, b, c and d. In position a the key may be inserted and removed. The cam may be rotated in a clockwise direction through position b to engage a side of the major slot 94 to thereby drive the deadbolt 22 towards the unlocked position.

In so driving the deadbolt, the detent spring 90 is lifted out of a first of the detent recesses 124. As the deadbolt approaches the unlocked position, the detent spring 90 drops down into a second of the detent recesses 122. At this time the key cylinder driving cam 92 is in position c, and the shape of the major slot 94 allows the driving cam to - 14 continue moving in a clockwise direction back to position a, in which the key may be removed from the key cylinder. This process may be reversed to move the deadbolt from the unlocked position back to the locked position.

When in the locked position, the anti-clockwise motion of the driving cam 92 is blocked on reaching position d, by the locking abutment 95.

Figure 6 shows a minor variation on the configuration of figure 5. It may be desirable to prevent the key from being removed from the key cylinder 90 when the deadbolt 22 is in the unlocked position, for example for security reasons. In the configuration shown in figure 6 this effect - is achieved using a cam block 130 which restricts the movement of the key cylinder driving cam 92 within the major slot 94. In figure 6, the deadbolt 22 is shown in the unlocked position, held in place by the detent spring 120.

However, continued clockwise motion of the key cylinder driving cam 92, in order to return to position a is blocked by the cam block 130, so that the key cylinder cam must remain in position b, or return in an anticlockwise motion thereby returning the deadbolt to a locked position.

The cam block 130 may be provided, for example, by plugging one or more prepared holes with appropriate press fit or screw-in pillars. In this way, a single design of deadbolt 22 can be used with or without the cam block facility.

Two further holes are shown in the head portion 26 of the deadbolt. These holes are first and second snib apertures 135. A snib mechanism may optionally be provided which IS adapted to engage with one or other of the snib apertures depending on the position of the deadbolt 22, to thereby hold the deadbolt in a desired position, for example against the action of one or more bias elements.

Figure 7 illustrates the deadbolt mechanism of figure 2, driven by an inner driving mechanism 140 operated by one or two rim key cylinders. If only one rim key cylinder is used, the deadbolt may be driven from the other side by a turnknob. Alternatively, turnknobs or key cylinders could be used on both sides.

A rim key cylinder will usually be mounted externally to the lock mechanism itself. A tang rotated by action of a key within the rim cylinder extends into a tang slot 142 in the centre of a rotatably mounted camming boss 144 which carries a rotating key cylinder driving cam 146. Two such, similar or identical camming bosses 114 are provided, facing in opposite directions. Between the two camming bosses 144 is located a core boss 148, rotationally mounted on the same axis of rotation as the camming bosses 144, and carrying a core boss driving cam 150 which is longer than the camming boss driving tangs 146.

The two camming bosses 114 may be arranged to always co-rotate, or preferably to rotate independently. Each camming boss provides, in addition to a central tang slot 142, features to enable to optional connection of a turnknob (not illustrated). In the arrangement of figure 7, these turnknob connection features 160 are in the form of apertures located on either side of the tang slot 142. The turnknob is then provided with pegs which extend into the turnknob connection features 160, extending through the camming boss 144. The core boss 148 may be provided with suitable spring clips or similar means to retain the ends of the pegs of the turnknob protruding through the camming boss 144. In this way, the camming boss 144 to which a turnknob - 16 is mounted may also be obliged to co-rotate with the core boss 148.

A minor slot 170 is provided within the major slot 94 previously discussed. The driving cam 150 of the core boss is engaged within the minor slot 170, so that rotation of the turnknob discussed above, if provided, is always coupled directly to the deadbolt 22. The core boss cam 150 is longer than each of the ramming boss driving cams 146 to facilitate this feature.

If either or both of the camming bosses 144 is rotatable independently of the core boss 148, then the camming boss driving cams 146 are able to engage with the major slot 94 to cause movement of the deadbolt 22 between the locked and unlocked positions largely as discussed above.

A rounded recess 172 is cut into the outer corner of the major slot 94 proximal to the head portion 26 of the deadbolt 22 to allow extra freedom of rotation of the camming boss driving cams 146. This is a minor alternation to the deadbolt 22 shown in the other figures.

A bias spring 175 is shown connected between the first spring pillar 126 discussed in connection with figure 4 and a bias spring hook 180 extending outwards from the arm 44 of the deadbolt 22 distal from the bolting member 10. The bias spring 175 shown IS helical and under tension, to urge the deadbolt 22 towards the locked position. Similar biasing arrangements could be used to urge the deadbolt in the opposite direction, if required.

A number of variations and alternative configurations to the lock mechanism described above may be made.

Generally, the components of the mechanism, especially the pivoting deadbolt element 22, are designed to make possible a large number of variations and configurations using different combinations of driving mechanisms, bias mechanisms, and so on. The lock mechanism may be used within or in conjunction with a variety of different bolting mechanisms. Although particular orientations of components and the lock mechanism as a whole have been used in the embodiments, other orientations may be appropriate for different circumstances. - 18

Claims

CLAIMS: 1. A lock mechanism comprising: a bolt member moveable between an

engaged position and a disengaged position; and a deadbolt rotatable about a pivot between a locked position in which movement of the bolt member is inhibited, and an unlocked position.
2. The lock mechanism of claim 1 wherein the deadbolt is provided with an aperture, the lock mechanism further comprising an inner driving mechanism arranged to drive the deadbolt between the locked and unlocked positions, the inner driving mechanism being at least partly located within the aperture.
3. The lock mechanism of claim 2 wherein the boundary of the deadbolt aperture comprises a major slot, and the inner driving mechanism comprises one or more rotating cams adapted to engage the major slot so as to drive the deadbolt between the locked and unlocked positions.
4. The lock mechanism of claim 3 wherein at least one of the one or more rotating cams is driven by a key cylinder located partly within or adjacent to the deadbolt aperture.
5. The lock mechanism of claim 3 wherein the inner driving mechanism comprises at least one rotatable camming boss carrying one of said rotating cams, said camming boss being provided with a central slot for accepting a key cylinder tang and one or more turnknob connection features for the connection of a turoknob.
6. The lock mechanism of claim 5 wherein the inner driving mechanism comprises two similar or identical camming bosses facing in opposite directions with a core boss located therebetween, the core boss being provided with a further rotating cam arranged to drive the deadbolt and one or more turnknob locking features for securing a turnknob connected through the turnknob connection features of one of the camming bosses.
7. The lock mechanism of claim 6 wherein the boundary of the deadbolt aperture comprises a minor slot located within the major slot, the lock mechanism being arranged such that the further rotating cam is engageable within the minor slot so as to drive the deadbolt between the locked and unlocked positions.
8. The lock mechanism of any of claims 2 to 7 further comprising an outer driving mechanism not located within the deadbolt aperture and arranged to drive the deadbolt between the locked and unlocked positions.
9. The lock mechanism of claim 8 wherein the outer driving mechanism comprises an electrical solenoid provided with a mechanical bias arranged to urge the deadbolt towards one of the locked and unlocked positions.
10. The lock mechanism of claim 8 or 9 wherein the external driving mechanism acts on the deadbolt by means of engagement with an outer driving slot located in the periphery of the deadbolt. -
11. The lock mechanism of any preceding claim wherein the deadbolt is provided with a bias spring hook, and a bias spring is coupled to the bias spring hook so as to urge deadbolt towards one of the locked and unlocked positions.
12. The lock mechanism of any preceding claim wherein the deadbolt has a detent surface comprising one or more detent minima, and the lock mechanism further comprises a detent spring acting upon the detent surface and favouring the detent minima so as to tend to hold the deadbolt in the locked and unlocked positions.
13. The lock mechanism of any preceding claim further comprising one or more microswitches, each microswitch having a switch arm bearing upon the deadbolt so as to sense a position of the deadbolt.
14. The lock mechanism of any preceding claim wherein the bolt member is moveable along a bolt axis between the engaged and disengaged positions and the axis of rotation of the deadbolt is spaced from and substantially perpendicular to the bolt axis.
15. The lock mechanism of any preceding claim wherein the deadbolt has a deadlock surface arranged to be in confrontation with a corresponding surface on the bolt member when the bolt member is in the engaged position and the deadbolt is in the locked position such that the bolt member is prevented from moving towards the disengaged position, the deadlock surface being substantially perpendicular to a radius extending therefrom to the axis of the rotation of the deadbolt.
16. The lock mechanism of any preceding claim wherein the bolt member IS a pushrod coupling a bolt driving mechanism to a bolt tip, so that operation of the bolt driving mechanism acts to move the bolt tip in a manner to secure door, window or other leaf within a frame.
17. The lock mechanism of claim 16 comprising at least one further pushrod and bolt tip commonly driven by the bolt driving mechanism.
18. A deadbolt for use in the lock mechanism of any preceding claim, comprising a pivot portion, two arms extending substantially radially from the pivot portion, and an arcuate portion joining the ends of the arms distal from the pivot portion.
19. The deadbolt of claim 18 further comprising a head portion located at one end of the arcuate portion and adapted to inhibit movement of the bolt member.
20. A bolting mechanism comprising one or more bolts driven by a common bolt driving mechanism, and a lock mechanism as set out in any of claims 1 to 17 arranged to selectively inhibit the movement of at least one of the bolts.