AU2007201008A1 - Improvements in Locks - Google Patents

Description

00 Title: Improvements in Locks Summary of the Invention: According to one aspect of the invention, there is a lock including a strike plate, a casing, a bolt supported by the casing to be displaceable to protrude from an aperture in the front edge of the casing to extend into an aperture in the the strike plate, the strike plate aperture having within a leading edge a protruding engaging shoulder that is engageable within at least one engageable recess in a side of the bolt to proved enhanced engagement between the bolt and strike plate.

In a second aspect of the invention, the engageable recess extends in a direction parallel to the plane defining the front edge of the casing.

In a third aspect of the invention, the the bolt includes at least one rail to guide the bolt through the aperture of the front edge.

In a fourth aspect of the invention, the bolt includes at least one rail from which the least one engageable recess extends.

According to another aspect of the invention, there is a lock including a strike plate, a casing, a bolt supported by the casing and having multiple engageable recesses in at least one side and at least one pair of spaced rails to guide the bolt through an aperture in the casing, (NI the bolt displaceable to exend into the aperture in the strike plate to enable tat least one of the engageable recesses to become engaged with a protruding engaging shoulder of the strike plate.

According to yet another aspect of the invention, there is a lock substantially as described herein with reference to and as illustrated in the 0 accompanying figures.

The elements relating to the various aspects of the invention claimed within are identified within the specification as follows, where unless the context requires otherwise: Specification shall be taken to include: a Body [comprising a Title, a Description of Preferred Embodiment/s, an Abstract and a Summary of the Invention] and Claims.

The word "locks" or variations such as "lock" will be understood to include complete locks for displaceable wings and improvements for locks for displaceable wings that are transportable into other locks and locking devices without being limited to the complete locks described herein.

The word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

The positional prepositions such as rear, forward are used to assist in description of the preferred embodiments and with reference to the accompanying drawings and have in general no absolute significance and "overlap" and derivations such as "overlaps" means at least in part occupying a same plane as.

The headings are included for convenience only and not to affect interpretation.

The word "preferably" or variations such as "prefer" does not mean nor infer that the form of an integer is restricted to that referred to as preferred as preferred unless the context requires otherwise, has the meaning of acceptable and able to perform the function required by the inventions in which it is included.

The words 'Wing" embraces both doors and windows and an "aperture" and a "recess" comprise a hole that extends from a surface An "engaging member" in isolated use, is displaceable between a fully displaced disposition and a fully retracted disposition. When employed with an "engagable means", the engaging member is displaceable between an operative disposition, a disposition in which the engaging member finds Sitself when engaged with the engagable means and an inoperative disposition removed from the said engagement.

"Latching" means displacement of an engaging member into engagement 0 with the "engagable means" under the action of biasing means.

A "latch-bolt" or latch bolt is an outwardly biased bolt capable of executing (or participating in) latching and includes bolts having a leading end that is Schamfered or otherwise profiled on one side to facilitate latching "Unlatching", unless the context requires otherwise means, withdrawal of r the engaging member from engagement with the engagable means, and for hinged door it includes withdrawal of the bolt from the aperture of the strike plate.

An "unlatching lever" is a lever or knob that is hand operable to cause the engaging member to become unlatched.

"Locking", unless the context requires otherwise, means the act of configuring the lock to restrain it from being unlatched and in some forms of locks employing deadlocking slides, it means restraining the deadlocking slide to restrain the bolt from being inwardly displaced by the unlatching lever.

"Deadlocking", unless the context requires otherwise, means to configure the lock to restrain the engaging member from being displaced from the fully displaced configuration by external forces (in the case of a common lock for a hinged door, it includes restraining the bolt in a fully extended position).

A "security Door", unless the context requires otherwise, means a door comprising a hollow framed door with an in-fill of mesh or woven stainless steel where the hollow within the frame is comparatively small in depth and in width. In general wings are supported adjacent an opening; the wing having a closing edge that in the closed position, is adjacent an element that helps define the extent of the opening; the lock being mounted relative to this closing edge and this may comprise mounting a lock body within the door.

A "lock body", unless the context requires otherwise, includes an engaging means and a casing; the lock body together with a strike plate, a pair of "handle assemblies" and a cylinder comprising a typical mortice lock, and where the lock body may be fitted within the frame of the wing; "depth" of lock body is the extent of the lock body in a direction parallel to the face of the door; "width" of lock body is the extent of the lock body in a direction at right-angles to the face of the door 0 This specification describes multiple other inventions that may be subject of divisional applications.

Description of the Drawings N Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which: SFig. 1 is an isometric view of a lock mounted adjacent to the closing edge of a wing, Fig. 2 is an isometric view of an associated strike plate, Fig. 3 is an isometric view towards the front of the lock, Fig. 4 is a horizontal cross-section through the bolt and casing.

One of the more common methods of gaining forced entry through a door and in particular, a security door is to apply a jemmy or large screw driver between the door and surrounding door jamb in the vicinity of the lock bolt to force the door away from the jamb to cause the bolt to disengage from the strike plate; this jemmying usually characterized by the door being urged outwardly as well as away from the door jamb. The inventions described herein, have as an objective providing enhanced engagement between the strike plate and bolt to better resist this disengagement.

The invention employs a substantially conventional strike plate 1 having a substantially planar portion 2 having apertures 4 to receive fixing screws; portion 2 being connected to a profiled wing 3. The portion 2 includes an engageable aperture 5 all this being common in conventional strike plates. The aperture however is adapted to include a profiled leading edge 6 that includes an inwardly protruding elongated engaging shoulder 7 that is preferably centrally located along the leading edge 6.

In some forms, the engaging shoulder 7 does not extend to either the top edge 20 nor to the bottom edges 21 of the aperture 5. This form giving rise to recesses 22 adjacent to the top edge 20 and the bottom edges 21.

The inventions further include a bolt 10 supported in a lock casing having at least one and in some forms of bolts multiple elongated engageable recess 11 that extend (in directions parallel the edge 7 of the strike plate aperture which in a common disposition of the lock comprises extending vertically) to be Sengageable by the engaging shoulder 7 whenever the bolt is within the aperture In some forms, the engageable recess extends from a position 12 adjacent to one edge of the bolt (that may comprise an upper edge) to a position 13 adjacent to the opposed edge of the bolt (that may comprise a lower edge); and some forms of bolts, there are multiple such engageable recesses spaced along a side 14 of the bolt.

C The bolt may be further configured such that the engageable recesses are spaced from adjacent to the mouth 15 of the lock to adjacent to the leading end S16 of the bolt and preferably all spaced at equally incremental distances.

In some forms of bolts, the side having the engageable recesses is substantially defined by a plane parallel the face of the wing, and another side that may be chamfered; in other forms, sides are substantially parallel and in some such forms the bolt has engageable recesses on both side and the leading end 16 may have a chamfered 17, bull-nosed or otherwise similarly profiled on each side to accommodate both left hand and right hanged doors.

In some forms of bolts, the upper side portion (of sides having multiple engageable recesses) are characterized by a rail 18 that acts as a bearing surface for the bolt to slide on as it is displaced over the side walls 23 of the mouth of the lock body; this rail providing an end wall for the engageable recesses. Similarly, the lower side portion (of sides having multiple engageable recesses) are characterized by a rail 19 that acts as a bearing surface for the bolt to slide on as it is displaced over the side walls 23 of the mouth of the lock body; this rail providing the other end wall for the engageable recesses.

The engagable recesses in orthogonal cross-section may be rectangular in form but in some forms it has a leading side 24 that in one form is inwardly inclined from a mouth 25 of the recess and it has a trailing side 26 that in one form is inwardly inclined from the mouth 25 of the recess each side being connected to a floor portion 27 (as shown in Fig the mouth being wider that the thickness 28 of the strike plate enabling the engaging shoulder 7 to enter the mouth 23 of an engagable recess.

During jemmying in which the wing is simultaneously urged away from the jamb and outwardly in an opening direction, the lock casing 30 (supported by the door) correspondingly carries the bolt away from the strike plate while carrying it outwardly. During the initial part of this displacement, a side 14 of the bolt is carried

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to be adjacent the leading edge 7 of the strike plate aperture, further displacement resulting in a) the engaging shoulder 7 either sliding along the side to subsequently enter the mouth 25 by sliding down a trailing side 26 to abut a floor portion 27, or b)

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the engaging shoulder 7 entering the mouth 25 to abut a floor portion 27, or c) the engaging shoulder 7 entering the mouth 25 to abut the leading side 24. In any Oevent, further displacement subsequently causing the leading edge 7 to become Sadjacent the leading side 24.

NAt this time, further jemmying (to urge the lock casing and bolt to displace simultaneously) urges the bolt from the strike plate but for this to happen, the leading side 24 must slide over the engaging shoulder 7 and to do so, the wing must displace inwardly against the urging caused by the jemmy; the result being an additional force being applied to the bolt having a component that urges the bolt outwardly and this results in a force that urges the wing against displacing away from the door jamb; this force also urges the strike plate towards the bolt to enhance the engagement between the strike plate and bolt.

In effect, the strike plate is drawn towards the bolt and in some cases, this mechanism will cause the portion comprising the peripheral edge of the recess 5 to deform to enable the engaging shoulder and engageable shoulder to remain engaged as the wing is displace away from the jamb to further enhance the engagement. This sometimes being referred to as a deformable strike plate.

It will be appreciated that the steeper is the leading side of the engageable recesses, the greater will be the force applied to the bolt to urge it outwardly.

However, a balance must be struck with a competing need for the unlatching lever to be able to easily retract the bolt (as the door is urged outwardly) and this becomes less easy as the leading side becomes steeper.