BACKGROUND OF THE INVENTION

THIS invention relates to a lock. More specifically, the invention relates to a lock having a locking plate, configured in a locked condition, to engage the substantial height of the free end of a door, thereby to make the door far more robust against attempted break- ins.

Most doors are capable of moving between open and closed conditions across a doorway, with the door typically being hinged along one vertical side to a doorframe within the doorway and lockable to the doorframe along an opposite free vertical side thereof. Generally, the free side of the door is lockable in a locked condition a lock bolt extending between it and the doorframe, which lock bolt is normally positioned mid- span along the height of the door.

It is common knowledge that to break the door from its locked position, one simply needs to point load the lock bolt beyond the breaking load of the lock bolt and/or the door. It is for this reason that many doors, particularly security gate doors, now comprise multiple lock bolts spread over the height of the door.

It will be appreciated that instead of making use of multiple lock bolts, which although safer are not very convenient, one might replace the multiple lock bolts with a single lock bolt acting substantially lover the entire height of the free end of the door.

One such lock is disclosed by LANGENBACH in US 4,844,521. This lock comprises a lock bolt in the form of an elongate lock plate capable of extending between the doorframe and a free edge of the door, thereby to spread the locking force acting on the free end of the door along its substantial height.

Unfortunately, LANGENBACH’s invention still comprises two vulnerabilities. The first is that the locking plate is bolted to the doorframe in only two locations. The second is that the locking plate, as well as a covering plate sandwiching the locking plate between it and the doorframe, have fairly low second moments of area making them weak against bending loads.

In use, and under loading during attempted break in, the load is better spread along the height of the door, but still not to the degree that would prevent point loading at the mounting points of the locking plate to the doorframe.

It is an object of the present invention to provide a lock inclusive of a means for better spreading load applied to the door substantially equally along its height, thereby to minimise the chances of point loading the locking plate or any mounting points thereof.

Reference to the terms“substantially parallel” and“substantially perpendicular” in this description will be understood to mean parallel and perpendicular, but also to include a variance from parallel and perpendicular of up to 15 degrees.

SUMMARY OF THE INVENTION

According to the invention there is provided a lock including: a housing being securable along a vertical edge of a doorway defined in a building wall such that an elongate height dimension of the housing operatively extends along the vertical edge of the doorway, the housing:

(i) comprising a width dimension as measured across a first plane lying in use substantially parallel with the surface of the building wall;

(ii) comprising a thickness dimension as measured across a second plane being substantially perpendicular to the first plane and in use lies substantially perpendicular to the surface of the building wall; and

(iii) defining an elongate slit extending at least partially along the height dimension of the housing; a locking plate being receivable within and movable relative to the housing between an extended condition, wherein the locking plate extends outwardly from the housing through the slit for operatively extending across the vertical edge of the doorway to engage a vertical edge of a door thereby to lock the door in a closed condition relative to the doorway, and a retracted condition, wherein the locking plate is at least partially retractable into the housing through the slit to operatively move clear of the vertical edge of the door thereby to enable the door to move between the closed condition to an open condition relative to the doorway, the locking plate comprising:

(i) an elongate height dimension extending at least partially along the elongate height dimension of the housing;

(ii) a width dimension as measured across a third plane being substantially parallel with the first plane; and

(iii) a thickness dimension as measured across a fourth plane being substantially parallel with the second plane; and a plurality of mountings for mounting the lock along the vertical edge of the doorway defined in the building wall; characterised in that, relative to respective neutral axes lying parallel with the first plane and cutting across the thickness dimensions of the respective housing and locking plate, the second moment of area of the housing is larger than that of the locking plate, such that any bending load operatively imparted onto the locking plate is transmittable to the housing, thereby to spread such bending load across the elongate height dimension of the housing, and consequentially between the mountings so as to restrict any one mounting from becoming overloaded and failing.

Generally, the elongate housing has at least:

(i) an elongate rear wall for operatively bearing against the building wall and mounting the housing to the building wall in a mounted condition; and (ii) an elongate side wall angularly offset from the rear wall of the housing, operatively in a direction away from the building wall.

Typically, the sidewall is substantially perpendicularly offset relative to the rear wall, with the side wall configured in the mounted condition such that the locking plate is movable into the extended condition either through relative movement:

(i) away from the side wall; or

(ii) where the sidewall defines the slit therein, toward the sidewall and through the slit.

Preferably, the housing includes a secondary sidewall being spaced from and substantially parallel with the slit-defining sidewall, the secondary sidewall and the slit- defining sidewall co-operatively defining an elongate cavity therebetween into which the locking plate is substantially housed in the retracted condition.

The lock may further include an elongate stiffener plate having an elongate height dimension extending at least partially along the elongate height dimension of the locking plate and mountable thereto such that the stiffener plate sandwiches the locking plate between:

(i) the stiffener plate and the rear wall of the housing; or

(ii) the stiffener plate and the building wall; characterised in that the mountings are elongate primary bolt and nut fastenings with the primary bolts operatively passing through at least:

(i) the building wall;

(ii) primary slots defined by the locking plate, each primary slot having a major dimension lying along the width dimension of such locking plate, for enabling movement of the locking plate between the retracted and extended conditions relative to the bolts and the stiffener plate in a direction across a width dimension of the stiffener plate; and

(iii) primary fastening apertures defined in the stiffener plate; such that the bending loading operatively imparted on the locking plate is transmittable to the stiffener plate and consequentially transmittable to the housing.

Furthermore, the lock may also include an actuator plate having an elongate height dimension extending at least partially along the elongate height dimension of the stiffener plate and mountable thereto such that the actuator plate sandwiches the stiffener plate between the actuator plate and the locking plate wherein: the primary bolts further operatively pass through secondary slots defined by the actuator plate, each secondary slot having a major dimension lying long the height dimension of such actuator plate, for enabling movement of the actuator plate between respective locking and unlocking conditions relative to the bolts and the stiffener plate in a direction along its height dimension; and secondary bolts passing through at least:

(i) tertiary slots defined by actuator plate, each tertiary slot having a major dimension lying angularly offset from and across a width dimension of the actuator plate;

(ii) quaternary slots defined by the stiffener plate, each quaternary slot having a major dimension lying along the width dimension of the stiffener plate; and

(iii) secondary fastening apertures defined in the locking plate; such that co-operation between the secondary bolt and riding in the tertiary and quaternary slots translate a back-and-forth movement of the actuator plate along its height dimenion into a back-and-forth movement of the locking plate between the extended and retracted conditons along its width dimension; charaterised in that the width dimensions of the housing, locking plate, stiffener plate and actuator plate coincide with one another. The housing may be tubular including a front wall being substantially parallel with the rear wall and spaced therefrom by the sidewalls such that the elongate cavity is co- operatively defined by the front wall, rear wall and sidewalls, and within which elongate cavity the stiffener plate and actuating plate are further housed.

Generally, the front wall of the housing defines:

(i) mounting receiving apertures for allowing the primary bolts or nuts to pass therethrough such that the respective primary bolts and nuts can be tightened to secure at least the stiffener plate and locking plate to the building wall;

(ii) secondary bolt receiving apertures through which the secondary bolts are receivable; and

(iii) a quinary slot having a major dimension lying along the height dimension of the housing, for receiving a free end of an actuator knob therethrough; wherein a second end of the actuator knob is connected to the actuator plate such that a back-and-forth force imparted onto the free end of the actuator knob, along the height dimension of the housing, is transmittable by the actuator knob to the actuator plate.

Preferably, the lock includes a plurality of low friction pads between the stiffener plate and the locking and actuator plates flanking each side thereof, thereby to minimise friction during relative movement therebetween.

BRIEF DESCRIPTION OF THE INVENTION

The invention will now be described in more detail, by way of example only, with reference to the accompanying illustrations, in which:

Figure 1 is a perspective view of a lock in accordance with the present invention fitted to a doorway, the lock being illustrated in a retracted condition; Figure 2 is a perspective view of the lock of figure 1 with the lock being illustrated in an extended condition;

Figure 3A-B are top views of the lock in each of the respective extended and retracted conditions;

Figure 3 is a side view of the cistern of figure 1 in a second flushing condition;

Figure 4 is a partially exploded perspective view of the lock of figure 1 ;

Figure 5A-B are zoomed-in perspective views of the lock of figure 1 ; and

Figure 6 is a fully exploded perspective view of the lock of figure 1.

DETAILED DESCRIPTION OF THE INVENTION

A lock according to a preferred embodiment of the invention is designated generally in the accompanying figures by reference numeral 10. The lock 10 comprises an elongate housing 12 and an elongate locking plate 14 slidably movable into and out of an elongate slit 16 defined in the housing 12.

With the housing 12 operatively mounted along a vertical edge 102 of a doorway or door frame 100, the locking plate 14 is movable into the housing 12 and consequentially into a retracted condition as illustrated in figure 1 , wherein the locking plate 14 is retracted wholly or at least partically into the housing 12 through the slit 16 and clear from a vertical free edge 200 of a door 202. It will be appreciated that the door 202 is movable between opened and closed conditions about hinged connections hingedly connecting the door 202 to a door frame 100 along an opposite vertical hinged edge 204 of the door 202.

With the locking plate 14 moving out of the housing 12 and consequentially into an extended condition as illustrated in figure 2, the locking plate 14 extends outwardly from the housing 10 through the slit 16 for operatively extending across a vertical edge 102 of the door frame 100, to engage the vertical free edge 200 of the door 202, thereby to lock the door 202 in a closed condition relative to the door frame 100.

Although the elongate housing 12 may take many different forms, a tubular housing having a quadrangular cross-section across its height dimension H _h has been used for illustrating the workings of this invention.

With reference to figure 3, the housing 12 comprises respective opposing front and rear walls 18, 20 spaced from one another across a thickness dimension T _h of the housing 12, as well as respective opposing primary and secondary sidewalls 22, 24 spaced from one another across a width dimension W _h of the housing 12, with the elongate slit 16 being defined in primary sidewall 22.

In use, the housing 12 is mounted by a plurality of mountings 26 such that its rear wall 20 bears against the vertical edge 102 of the door frame 100 (or against the building wall 104 itself), with the primary sidewall 22 and the slit 16 defined therein facing in the direction of the door 202.

It will be appreciated that the rear wall 20 comprises a width dimension W _h as measured across a first plane lying substantially parallel with the surface of the building wall 104, with the thickness dimension T _h of the housing 12 being measured across a second plane being substantially perpendicular to the first plane.

It will be appreciated that the walls 18, 20, 22, 24 of the housing 12 co-operatively define an elongate cavity 28, into which at least the locking plate 14 is at least partially housed in the retracted condition.

With reference now also to figure 4 and figure 5, the lock 10 further includes an elongate stiffener plate 30 having an elongate height dimension Hs extending along the elongate height dimension Hi_ of the locking plate 14 and mountable thereto such that the stiffener plate 30 sandwiches the locking plate 14 between itself and the rear wall 20 of the housing 12. It will be appreciated that where the housing 12 has a shape other than tubular, the stiffener plate 30 may sandwich the locking plate 14 between itself and the door frame 100, or the building wall 104. The mountings 26 are made up of elongate primary bolts 26A and correspondingly threaded primary nuts 26B. In use, each of the elongate primary bolts 26A are pushed sequentially through:

• a hole drilled in the building wall 104 (not shown);

• a hole in the rear wall 20 of the housing 12 (not shown);

• an open-ended primary slot 32 defined by the locking plate 14 and positioned thereon such that a major dimension of the primary slots lie along the width dimension Wi_ of the locking plate 14, with the width dimension Wi_ being measured across a third plane being substantially parallel with the first plane; and

• a primary fastening aperture 34 defined by the stiffener plate 30.

With the elongate primary bolts 26A pushed into position, the primary nuts 26B are positioned through mounting receiving apertures 36 defined by the housing 12 to threadably tighten onto the primary bolts 26A, thereby to secure the lock 10 onto the the dorr frame 100.

In use, the primary bolts 26A ride in the respective primary slots 32 thereby to enable movement of the locking plate 14, between the retracted and extended conditions, in a direction across the width dimentsion Ws of the stiffener plate 30.

It will be apprecated that with the locking plate 14 and stiffener plate 30 working in close proximity with one another, any bending load operatively imparted on the locking plate 14 is transmittable to the stiffener plate 30, and consequentially transmittable to the housing 12.

The lock 10 also includes an actuator plate 38 having an elongate height dimension H _A extending at least partially along the elongate height dimension Hs of the stiffener plate 30, and being mountable thereto such that the actuator plate 38 sandwiches the stiffener plate 30 between it and the locking plate 14.

At least some of the primary bolts 26A are also pushed through secondary slots 40, defined by the actuator plate 38 with each having a major dimension lying along the height dimension HA thereof and being sized to enable the primary nuts 26B, secured to the primary bolts 26A, to ride freely therein such that the actuator plate 38 is moveable operatively up and down the stiffener plate 30, between unlocked and locked conditions.

The actuator plate 38 is slidably secured to the stiffener plate 30 by secondary bolts 42 pushed sequentially through:

• secondary bolt receiving apertures 44 defined by the housing 12;

• tertiary slots 46 defined by actuator plate 38 having a major dimension lying angularly offset from and across a width dimension W _A of the actuator plate 38;

• quaternary slots 48 defined by the stiffener plate 30 having a major dimension lying along the width dimension Ws of the stiffener plate 30; and

• secondary fastening apertures 50 defined in the locking plate 14.

An actuator knob 52 extends through a quinary slot 54 defined by the housing 12, thereby to transmit an operatively back-and-forth movement imparted on the knob by a user, to a back-and-forth movement of the actuator plate 38 along the stiffener plate 30 in an operatively vertical plane.

Co-operation between the tertiary and quaternary slots 46, 48 with the secondary bolts 42 riding there along translate the back-and-forth movement of the actuator plate 38 along its height dimenion H _A into an in-and-out movement of the locking plate 14 between the extended and retracted conditons along its width dimension W _L .

It will be appreciated that a load applied to the door 202 during an attempted breakin, particularly at one of the vertical ends thereof, would normally have the effect of causing a bending load across the height dimension of H _L of the locking plate 14.

With the locking plate 14 being in the form of a flat plate, with a low second moment of area (relative to a neutral axis passing centrally through locking plate thickness dimension T _L , as measured across a fourth plabe being substantially parallel with the second plane), the bending load would manifest itself as a deflection along the height dimension H _L of the locking plate 14. The deflection would have the effect of point loading the mounting closest in proximity to the to the position at which maximum deflection is being experienced by the locking plate 14, until the mounting fails due to overloading.

Through the construction of the lock 10 of the present invention, the bending loads of the locking plate 14 are transmittable to the stiffener plate 30 and/or the housing 12, directly and/or indirectly. The increase in second moment of the area offered by these two components (relative to respective neutral axes passing centrally through Ts and T _h ) increases the ability of the lock 10 to spread the bending load over its span, thereby reducing deflection and consequentially reducing point loading on any of the mountings 26.

Although the invention has been described with reference to a preferred embodiment, it will be appreciated that many modifications or variations of the invention are possible without departing from the spirit or scope of the invention.

For example, the lock 10 preferably includes a plurality of low friction pads 56 between the stiffener plate 30 and the locking and actuator plates 14, 38 flanking each side thereof, thereby to minimise friction during relative movement therebetween.