EP1913217A2

EP1913217A2 - Features for convenient mortise lock installation

Info

Publication number: EP1913217A2
Application number: EP06766153A
Authority: EP
Inventors: Martin Stace; Gary Brookes; Simon Baker; Andrew Wilkes
Original assignee: Assa Abloy Ltd
Current assignee: Assa Abloy Ltd
Priority date: 2005-08-12
Filing date: 2006-07-19
Publication date: 2008-04-23
Anticipated expiration: 2026-07-19
Also published as: EP1913217B1; WO2007020623A3; AR054884A1; WO2007020623A2; TW200720519A

Abstract

A mortise lock assembly for a door, including a casing (1) , a locking mechanism arranged at least partly within the casing, and a plurality of location elements (17) extending from the rear wall (3) , for indicating a position for forming a recess in the door for receiving the lock assembly. Other non-limiting features allow the lock installer to decide what spring strength to give the handle of the mortise lock without having to carry two different locks in stock. Another non-limiting feature is an external sensor module that permits adding a microswitch or other sensor without having to provide it inside the lock.

Description

FEATURES FOR CONVENIENT MORTISE LOCK INSTALLATION FIELD OF THE INVENTION

The present invention relates generally to mortise lock assemblies and to features for convenient installation of mortise locks.

BACKGROUND OF THE INVENTION

One of the most widely used forms of lock is a mortise lock. The mortise lock assembly is mortise fitted within a recess that opens at the side edge of the door, that is, the edge that, when the door is closed, abuts the adjacent surface of a door jamb. Because the main body of the lock including most of its operational parts is within the door itself, it is difficult for an intruder to gain access to those operational parts, thereby making it difficult for the intruder to gain unauthorized entry to a locked room or area.

In order to fit a mortise lock, a recess ("mortise") suitably configured for receiving the lock has to be created in the opening edge of the door. The formation of the mortise is a relatively laborious process, and requires relatively precise positioning of the mortise relative to any strike or other object with which in use the lock is intended to cooperate.

Many conventional lock assemblies include a handle, which for secure locking of the door must be returned to its starting position after the door is closed. It is usual to include a spring return system for returning the handle to its starting or rest position. In the use of the existing lock assemblies, however, the spring system does not always fully return the handle. It would be desirable for a lock assembly to allow for the spring force acting to return the handle to be increased, if desired or if necessary to return the handle to its starting position.

It is sometimes desired to include with the lock a sensor device, which is arranged to provide a signal to a remote point, the signal indicating whether the lock is in the locked or unlocked condition. Conventionally, the sensor device is added to the lock on fitting, but that is a relatively laborious process. There is a need for a mortise lock assembly that is of simple construction but can nonetheless include a sensor device for monitoring whether or not the lock is in the locked condition.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved mortise lock assembly with features for the convenience of the installer or provider of mortise locks that address the abovementioned needs, as is described in detail further hereinbelow.

Some of the features include protrusions that help the person mark the aperture for installing the lock. Other features allow the installer to decide what spring strength to give the handle of the mortise lock without having to cany two different locks in stock. Another feature is an external sensor module that permits adding a microswitch or other sensor without having to provide it inside the lock.

There is thus provided in accordance with an embodiment of the present invention a mortise lock assembly for a door, including a casing, a locking mechanism arranged at least partly within the casing, and a plurality of location elements extending from the rear wall, for indicating a position for forming a recess in the door for receiving the lock assembly.

The location elements provided in accordance with the invention enable a location for forming of a recess within a side edge of a door to be marked by means of pressing the location elements against the side edge. Making use of the marks so formed, it is made possible for the recess to be formed relatively easily and quickly. The use of the location elements to provide location marks, which can then be used as a guide for forming the recess, also allows the position of the recess to be determined with relatively high precision. The location marks may be formed in any suitable way. Preferably, they are formed by means of forcing the lock assembly against the side edge of the door such that the location elements form recesses in the side edge. Any other suitable marking method may however be used.

The invention also provides a mortise lock assembly for a door, including a casing having a front faceplate and a rear wall opposed to the front faceplate, a locking mechanism arranged at least partly within the casing, the casing further including an upper wall and a lower wall, each extending from the faceplate to the rear wall and at least one of the upper and lower walls being of convexly curved configuration.

Use of a casing having convex upper and lower walls has been found to offer advantages on fitting the lock assembly.

In one especially preferred embodiment of the invention there is provided a mortise lock assembly for a door, including a casing having a front faceplate and a rear wall opposed to the front faceplate, the casing further including an upper wall and a lower wall, each extending from the faceplate to the rear wall and at least one of the upper and lower walls being of convexly curved configuration, a locking mechanism arranged at least partly within the casing and having a locking member for engaging with a strike member, a plurality of location elements extending from the rear wall, for indicating a position for forming a recess in the door for receiving the lock assembly, wherein the rear wall is of elongate configuration and is bounded by opposed longitudinally extending side edges and opposed end edges, the opposed end edges being of arcuate configuration, and there is at least a first location element that is substantially coincident with the centre of the arcuate upper edge of the rear wall and there is at least a second location element that is substantially coincident with the centre of the arcuate lower edge of the rear wall.

In the fitting of a lock assembly having the arrangement of location elements and arcuate edges, the precision of fitting of the lock assembly can be improved.

References herein to improvements in the precision of the fitting of lock assemblies are to be understood as referring to improving the precision of fitting by a fitter of a given skill level.

Advantageously, the location elements are fixedly attached to the rear wall of the casing. The location elements are preferably integrally formed with the rear wall of the casing, for example as a metal casting. The location elements may be projections, for example, elongate pointed projections.

Advantageously, the rear wall is of elongate configuration being bounded by opposed longitudinally extending side edges and opposed end edges, at least one of the end edges being arcuate. Advantageously, there are opposed and oppositely arcuate end edges. Advantageously, the arcuate end edges are substantially hemispherical and concentrically arranged with respect to a respective location element. There may be two location elements associated with arcuate ends of the rear wall, and at least one additional location element positioned therebetween. Advantageously, there are a total of three to eight location elements.

Advantageously, both the upper and lower walls are of convexly curved configuration, preferably of substantially semicircular convex configuration. Advantageously, the semicircular configuration has a radius which is substantially uniform along the upper and lower walls from the face plate to the rear wall.

It is preferred that there are present on the rear wall a first locating element in the vicinity of the upper wall and a second locating element in the vicinity of the lower wall, the first locating element being substantially centrally positioned on the rear wall relative to the curvature of the upper wall and the second locating element being substantially centrally positioned on the rear wall relative to the curvature of the lower wall. Advantageously, there are a multiplicity of location elements arranged in a line and spaced apart along the length of the rear wall.

The invention further provides a method of fitting a mortise lock assembly in a door, including forming at least upper and lower location marks by placing the lock assembly against a door edge, forming upper and lower bores centered on the upper and lower location marks and having a diameter approximating to the thickness of a casing of the lock assembly to be received in the door, if necessary removing material between the upper and lower bores to form a recess extending continuously from an upper, curved surface of the upper bore to a lower, curved surface of the lower bore, and inserting into the recess a lock having convexly curved upper and lower walls conforming generally in configuration to the upper, curved surface and the lower, curved surface, respectively.

The invention also provides a lock assembly for a door, including a casing, a locking mechanism arranged at least partly within the casing and having a latch bolt, a handle, the handle being in operative connection with the latch bolt, a first spring assembly for applying a first return force to the handle, and a second spring assembly for applying a second return force to the handle.

The provision of a second spring assembly allows the return force acting upon the handle to be adjusted to meet desired or required conditions. For example, the second spring assembly allows an increased return force to be selected where the handle is relatively heavy and/or where the lock furniture is unsprung.

It is preferred for the second spring system to be activated before the lock is fitted. In general, the second spring system will not be capable of activation after the lock assembly has been fitted into a door. For example, an activating device for the second spring assembly may be so arranged that it is concealed after the lock assembly has been fitted. Arrangements in which the second spring system can be activated after the lock has been fitted are not, however, excluded.

The first spring system preferably includes a compression spring. Compression spring arrangements for applying a return force to a handle in a door lock are known and the first spring system may be a conventional compression spring arrangement of the type previously used in mortise locks for that purpose. The compression spring may be a helical compression spring.

The second spring assembly provided in accordance of the invention may include a compression spring. It is preferred for the spring to be a helical compression spring.

It is preferred for the second spring assembly to include a pivotably mounted housing. In a preferred arrangement, the door handle includes a lever having two lever arms for transmitting a force from the first spring assembly to the latch bolt, and having a further projection which in use cooperates with the second spring assembly. A first the lever arm may be arranged to act upon a bolt assembly including a spring and the latch bolt. The second spring assembly is advantageously arranged to apply a return force to the handle even when the latter is fully returned to its stalling position.

The invention further provides a method of fitting a lock assembly in a door, including providing a primary spring assembly for applying a return force to a handle of the lock assembly and effecting adjustment of a secondary spring assembly, the secondary spring assembly being so adjusted that it influences a total return force applied to the handle, and fitting the lock assembly into a door.

The invention provides a mortise lock assembly for a door, including a casing, a locking mechanism arranged at least partly within the casing, a recess in the exterior of the casing for receiving a sensor module for monitoring the locking mechanism, and a removable module received in the recess.

The structure of the invention enables a lock assembly to be provided in simple fashion with a sensor during or after manufacture. For example, the lock assembly may be provided, during manufacture, with a module housing a sensor, or may instead be fitted with a blank module during manufacture, which can then optionally be replaced by a module including a sensor when the lock is to be fitted.

In general, it is preferred for the recess to be in communication with the interior of the casing, for example via an aperture in the base of the recess. Any suitable kind of sensor may be used. For example, the sensor may be a mechanical sensor which, in use, detects mechanically through the aperture whether the lock mechanism is engaged. It is preferred, however, for the sensor to be an electrical sensor.

The sensor module can be pre-manufactured so as to be capable of simple insertion in modular fashion into the recess. In addition to simplifying fitting, that reduces the risk of malfunction of the sensor through poor fitting thereof. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:

Fig. l is a perspective view of a mortise lock assembly for a door, constructed and operative in accordance with an embodiment of the present invention, showing location elements extending from the rear wall of the lock assembly, for indicating a position for forming a recess in the door for receiving the lock assembly;

Fig. 2 is a side view of the assembly of Fig. 1 ;

Fig. 3 is a rear view of the assembly of Fig. 1 ; Figs. 4 and 5 are side views of a lower part of the lock assembly of Fig. 1 with its casing removed and with a second spring assembly, constructed and operative in accordance with an embodiment of the present invention, shown in non-operative and operative positions, respectively;

Fig. 5 A is a more detailed illustration of the second spring assembly;

Fig. 6 is a perspective view of a lock assembly according to the invention, having a sensor module, constructed and operative in accordance with an embodiment of the present invention;

Figs. 7a and 7b are side views of the sensor module, with the door locked and unlocked, respectively;

Fig. 8 is a side view of the lock assembly with the side wall removed and with the door unlocked;

Fig. 9 is a top view of the lock assembly of Fig. 6, and

Fig. 10 is a perspective view of a top portion of another lock assembly according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

With reference to Fig. 1 , the lock assembly is in many respects conventional. It is a mortise lock and includes a lock casing 1 into which the locking mechanism of the lock is fitted. The lock casing includes a face plate 2 and a rear wall 3. The lock casing also includes opposed side walls 4 and opposed upper and lower walls 5 and 6, respectively.

The lock assembly shown in the drawings is suitable for use in a variety of doors, for example, but not exclusively, in a sliding door. It includes a hook bolt 7, which is arranged in the vicinity of an aperture (not shown in the drawings) in the faceplate 2. The hook bolt 7 is arranged to be interlockable, through that aperture, with a strike mounted on a door jamb, for example with a cooperating member or aperture provided on the strike. The cooperating member and strike are not shown in the drawings. The lock assembly is designed to be mortise fitted within the section of a part of the door, typically within a frame section of the door. When received within the door, the housing of the lock assembly is concealed except for the faceplate 2, which is arranged to be substantially in the same plane as the surrounding surface of the side edge of the door, that is, the surface that in use will be the leading surface when the door is slid shut. The casing includes apertures for receiving other lock furniture, including a handle (aperture 8) and a lock cylinder (aperture 9). Reference numerals 10, 11 and 12 designate securing means, for example, screws or rivets which hold the casing in place about the locking mechanism. When the lock has been fitted, the lock cylinder and handle extend through at least the front face of the door.

The rear wall 3 of the lock assembly is of generally elongate configuration, having two longitudinally extending edges 13 and 14 and two end edges 15 and 16. The two end edges 15 and 16 are of arcuate configuration and extend between the longitudinal edges at the ends thereof.

In accordance with a non-limiting embodiment of the invention, spaced equidistant from one another along the rear wall are a plurality (e.g., seven) of location elements 17¹ to 17⁷ in the form of projections. In the embodiment shown, each projection is of substantially circular cross-section terminating in a distal tip 18¹ to 18⁷ which is of smaller cross-section than a proximal portion of the projection. The cross-sectional configuration of the projections may be different from that shown. For example, the projections may be of square cross-section, or they may be of pyramidal configuration. The projections are rigidly attached to the rear wall 3. In practice, it will usually be expedient to form both the rear wall and the projections integrally, for example as a metal casting. Suitable metals include, inter alia, zinc and composite metal alloys, although any suitable material may be used.

The projections 17¹ to 17⁷ are arranged in a straight line extending longitudinally along the centre of the rear wall. The terminal projections, that is, the projections 17¹ to 17⁷ that in the fitted lock assembly will be at the top and at the bottom, respectively, of the line of projections are so located relative to the arcuate end edges 15 and 16 that the centre defined by the arcuate edge coincides with the centre of the respective projection. Thus, projection 17¹ is located at the centre of an imaginary circle of which arcuate edge 15 defines a part. Projection 17⁷ is located at the centre of an imaginary circle of which arcuate edge 16 defines a part. In the embodiment shown, the arcuate edges 15 and 16 are substantially semi-circular, which is preferred but not essential. It is preferred for the arcuate edges to be substantially semi-circular and to have a centre coinciding with the centre of the terminal projection. The upper and lower walls 5 and 6 of the casing 1 are each of semi-cylindrical configuration and are configured to have a curved surface having substantially the same radius as the arcuate edges 15 and 16.

References to coincidence with the centre of one of the projections are in general to be understood as meaning that the centre is substantially coincident with a central region of a tip of the projection that, in use, causes a location mark to be generated on the side edge of the door. It is preferred for the tip of each terminal projection 17¹ - 17⁷ to be centrally located with respect to an imaginary circle of which the respective arcuate edge 15 or 16 is a part because, in use, a cylindrical bore generated in the side edge of the door, centered upon a location mark made by the associated projection, and having a suitable diameter, will generate an internal surface that substantially corresponds to the curved outer configuration of the upper wall or the lower wall, respectively, of the casing. That arrangement serves considerably to simplify the fitting of the lock assembly into the door.

Reference numeral 19 indicates an aperture for receiving an optional cable for a lock sensor. Reference numerals 20 and 21 indicate apertures for receiving screw fastening elements.

In use, the rear wall 3 of the lock assembly is placed against the side edge of the door in the position in which the lock assembly is to be mounted. The lock assembly is pushed against the side edge with sufficient force that a series of location marks is produced, one corresponding to each location element 17¹ to 17⁷. A drill bit having a diameter substantially the same as the imaginary diameter of the arcuate edges can then be used to drill upper and lower bores, centered at the location marks at the top and the bottom, respectively, of the series of marks. The resultant bores will have an inner surface which, at the top of the upper bore and at the bottom of the lower bore, approximate to the configuration, respectively, of the upper and lower casing walls 5 and 6. The intervening material of the door can then be removed by drilling bores of similar diameter centered upon the intervening location marks, resulting in a mortise that requires little or no further shaping to receive the lock assembly. In that manner, the recess can be formed simply, quickly, and with precise positioning.

Reference is now made to Fig. 4, which illustrates a lower part of the lock assembly with external walls omitted and with certain parts of the lock mechanism omitted for ease of illustration. The latch bolt 8 and its operating mechanism are located in the lower part of the assembly shown in Fig. 4.

The latch bolt 8 is retractable and extendable through an aperture in the faceplate 2 by means of a slidable member 113 which can be advanced and retracted by a lever arm 114. The slidable member 113 has a ratchet edge 115 which can interlock with a deadlock mechanism (not shown) so as to enable the latch bolt to be locked in the closed position when desired. The latch bolt mechanism includes a compression spring 1 13a. Except for the ratchet edge 115 and the interaction with lever arm 114 further described below, the structure and operation of the latch bolt, the slidable member 113 and the associated spring 113a are essentially conventional and do not therefore require more detailed description. A lever 116 comprising the lever aim 114 and a further lever aim 117 is mounted about a square shaft 118 of a door handle. The second lever arm 117 is acted upon by a first spring assembly 119. A second spring assembly 120 is shown adjacent to the second lever aim 117. First spring assembly 119 includes a fixedly mounted stop 121 and a movable plate 122 between which is located a compression spring 123. An elongate shaft 124 extends from the stop 121 along the inside of the spring towards the movable plate. A hollow tubular body 125 extends from the movable plate 122 towards the stop 121, and surrounds the shaft 124 for a part of its length. The tubular body 125 is axially movable with respect to the shaft 124 on movement of the movable plate 120. The tubular body 125 is made up of a proximal length 126, extending from the plate 122, and a distal length 127, having an enlarged internal and external diameter relative to the proximal length.

The second lever arm 117 of the lever 116 contacts the movable plate 122 and, on turning of the door handle is caused by the rotary movement of shaft 118 to impart translational movement to plate 122, compressing spring 123. The arrangement is such that, when the handle is operated and the lever moved in a clockwise direction, the spring 123 is compressed, as a consequence of which the spring assembly 1 19 applies a return force to the lever arm 1 17 urging the handle shaft 1 18 and the handle back to their starting position. The lever 1 16 is additionally provided with a projection 128, the function of which is described in more detail with reference to Fig. 5 below.

The second spring assembly 120, which is described in more detail with reference to Fig. 5 A, is associated with a switch mechanism 129 including a button or slide 130 received in a member 131 that is configured to be received in a recess in the casing of the lock assembly.

Referring to Fig. 5, the parts shown are as in Fig. 4 except that the second spring assembly 120 is arranged in an operative position in which an end is in contact with the projection 128. In that manner, a compressing force is applied to the spring assembly 120 when the shaft 118 is turned using the door handle so as to retract the latch bolt 8. As a consequence thereof, the spring assembly 120 applies a returning force to projection 128, and thus to the door handle, whenever the handle is in a position other than its usual rest position.

With reference to Fig. 5 A, the second spring assembly 120 has a housing 132 having first end 133, second end 134 and pivots 135 and 136 which are arranged to be received in corresponding apertures in the casing of the lock assembly (those apertures not being visible in Figs. 4 and 5 in which the casing is omitted). The housing has opposed slots 137. The first end 133 has a cap having a central aperture 138 surrounded by a substantially annular portion 139 the inside surface of which provides a bearing surface for a first end of a compression spring 140 associated with the cap and extending axially along the interior of the housing 132. An end piece 141 is fixed into the other end 142 of the spring 140. The end piece 141 has two opposed projections 143 and 144 which engage slidingly in the opposed slots 137. A central recess 145 (see Figs. 4 and 5) is provided in the outer surface of end piece 141 for receiving a curved edge 146 of the projection 128. The projection 128 and the spring assembly 120 are so arranged that, when the spring assembly 120 is in the operative position shown in Fig. 5, rotation of the lever 116 in the clockwise direction causes the projection 128 to apply a compression force to the spring 140 via the end piece 141 upon which the projection 128 acts. As a result the spring 140 is compressed axially within the housing 132, the projections 143 and 144 being slidably retained in the slots 137 whilst the slots 137 also permit the adjacent, planar, portion of the projection 128 to follow the end piece 141 axially along the housing 132 and to continue pressing against the end piece 141 whilst turning of the lever 116 continues. Upon release of the door handle, the compressed spring 140 applies a return force upon the projection 128 tending to return that projection to the starting position shown in Fig. 5.

On the external surface of housing 132 near the second end 134 there is provided a projecting member 147 having a cut-out region 148 between two arms 149 and 150.

The lock assembly includes a mechanism for transferring the second spring assembly 120 from the inoperative position in Fig. 4 to the operative position in Fig. 5, the mechanism comprising the slide 130 and the projecting member 147 of the second spring assembly 120. A rear element 151 of the slide 130 protrudes through an aperture (not visible in the drawings) in the slide member 131 and can cooperate with the cut-out 148.

By sliding the slide 130 to the right, the spring assembly 1 19 can be pivoted upwards by means of the element 149 engaging in the cut-out 148 and acting upon the right hand arm 150 to cause pivoting of the spring assembly about pivots 135 and 136 and urging the end piece 141 into contact with the projection 128. Once the projection becomes engaged in the central recess in end piece 141, the return of the spring assembly 120 to the inoperative position is deterred. In use, the handle is turned by the user causing clockwise rotation of lever 116, with the lever ami 117 acting upon the first spring assembly 119 and the projection 128 acting upon second spring assembly 120. The second spring assembly 120 augments the action of first spring assembly 117, assisting in urging the lever 116, and thus the associated handle, back to its starting position.

Should augmenting of the action of the first spring assembly not be required, for example because the door is to be used in an area where children, or elderly or disabled people may need to use it, the lock assembly can be used without bringing the second spring assembly into the operative position.

The lock assembly can be fitted in essentially the same manner as conventional mortise locks. Before placing the lock assembly within the door, however, the switch mechanism 129 is, if desired, activated to cause the second spring assembly to operate and thus to influence the return force on the handle after the lock as been fitted. Alternatively, the switch mechanism 129 may be deactivated such that the second spring assembly is not operational after the lock has been fitted. Once the lock has been fitted, the switch mechanism 129 is concealed behind the face of the door.

Reference is now made to Fig. 6, which illustrates a lock assembly having a sensor module, constructed and operative in accordance with an embodiment of the present invention. he lock assembly is in many respects conventional. It is a mortise lock and includes a lock casing 201 into which the locking mechanism of the lock is fitted. The lock casing includes a faceplate 202 and a rear wall 203. The lock casing also includes opposed side walls 204 and opposed upper and lower walls 205 and 206.

The lock assembly shown in the drawings is a mortise lock suitable for use in a door, for example, but not exclusively, a sliding door. Whilst the invention is described below with reference to a lock having a hook bolt, it is also applicable to locks having other kinds of bolts. The lock assembly includes a hook bolt 207, which is arranged in the vicinity of an aperture in the faceplate 202. The hook bolt 207 is arranged to be interlockable with a keeper mounted on the door jamb, for example with a cooperating member or aperture provided on the keeper. The cooperating member and keeper are not shown in the drawings. The lock assembly is designed to be mortise fitted within the section of a part of the door, typically within a frame section of the door. When received within the door, the housing of the lock assembly is concealed except for the faceplate 202, which is arranged to be substantially in the same plane as the surrounding surface of the side edge of the door, that is, the surface that in use will be the leading surface when the door is slid shut. In use, other lock furniture may be affixed to the lock assembly. For example, a lock cylinder and a handle (not shown in Fig. 6) may extend through the front face of the door.

In an upper region of the lock assembly is a recess 208 for receiving a module 209 including a sensor 210. At the bottom of the recess is a rectangular aperture 211 communicating with the interior of the casing. Adjacent to the recess 208 in the front, in the upper wall, is a bore 212 for receiving an attachment screw. Adjacent to the recess at the reai- are a series of upstanding guides including two guides 213 that could have an open-topped region 214 and a number of further guides 215 that each include an aperture 216 aligned with open-topped regions 214. When the module 209 is placed in the recess, a cable 217 for transmitting signals to and from the sensor can be passed through the apertures 216, the part of the cable nearer the module 209 then being receivable snugly in open-topped regions 214 as shown in Fig. 9. There may be more or fewer than two guides 213 including open-topped regions 214. An embodiment having a single guide 213 is shown in Fig. 10.

With reference to Fig. 7a, the module 209 comprises a housing 218 and a sensor device 219 partially contained within the housing. The housing 218 includes an extension portion 218a having an aperture which can be positioned in register with the bore 212 whereby an attachment screw (not shown) can be inserted through the extension portion 218a and into bore 212 for fixing the module into position. A sensing portion 220 of the sensor device protrudes beyond a lower wall of the housing and, when the sensor module 209 is placed within the recess 208, extends through the aperture 211 into the interior of the housing where it is so positioned that it can sense whether the hook bolt 207 is in the locked position. In Fig. 7a, the hook bolt is shown in the locked position, with a contact surface 221 of the hook bolt removed from the sensing portion 220. Fig. 7b shows the lock assembly in an unlocked condition in which the contact surface 221 of the hook bolt has moved into contact with the sensing portion 220. Sensor devices for monitoring locks are known and further description of the sensor itself is therefore unnecessary. It will be appreciated that any suitable sensor can be used, provided that it is suitable for incoiporation into a modular unit.

Figs. 8 and 9 show the module in situ with the cable 217 passing through the guides 213 and 215. In the embodiment of Fig. 10, many of the parts are identical or similar to corresponding parts in the embodiment of Figs. 6 to 9, and are shown with corresponding reference numerals. As already mentioned, there is a single guide 213 with an open- topped region 214, whilst the remaining six guides 215 have apertures through which cable 217 can pass. The embodiment of Fig. 10 is shown with a blank module 222 having an extension portion 222a in place of a sensor module 209. The blank module 222 can be removed and replaced by a sensor module 209 (for example of the structure shown in Figs. 7a and 7b) before fitting the lock, if desired.

In the embodiments shown in Figs. 6 to 10, the module is attached to the casing by screw-threaded means. It will be appreciated that any other mode of attachment may be used, for example the module may be arranged to be attached by other fastener devices or to fit in snap-fit fashion into the recess.

In practice, when the lock is manufactured, it may be equipped either with a sensor module or, alternatively, with an empty casing module which occupies the recess. Where the lock is manufactured with the sensor module in situ, all that the fitter is required to do is to fit the lock as normal. Where the lock is supplied with an empty casing module in place of the sensor module, the empty casing module can be removed and replaced by the sensor module. After attachment of the sensor module into the recess, the lock assembly can be fitted in the normal way.

Whilst there is described above a mortise lock assembly having a hook bolt, the invention is applicable to any mortise lock. In particular, it will be appreciated that the provision of case fastening elements as claimed herein may be applied to mortise locks having hook bolts or other types of bolt, and which are suitable for any kind of door, including hinged doors or sliding doors.

It is appreciated that various features of the invention which are, for clarity, described in the contexts of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Claims

CLAIMS What is claimed is:

1. A mortise lock assembly for a door, comprising: a mortise lock casing having a front faceplate and a rear wall opposed to the front faceplate; and a plurality of location elements extending from the rear wall, for indicating a position for forming a recess in the door for receiving the lock assembly.

2. The mortise lock assembly according to claim 1, in which the location elements are projections that protrude outwards from the rear wall.

3. The mortise lock assembly according to claim 1 or claim 2, wherein the projections are arranged in a straight line extending longitudinally along the centre of the rear wall.

4. The mortise lock assembly according to any one of the preceding claims, in which the rear wall is of elongate configuration being bounded by opposed longitudinally extending side edges and opposed end edges, at least one of the end edges being arcuate.

5. The mortise lock assembly according to claim 4, in which there are opposed and oppositely arcuate end edges.

6. The mortise lock assembly according to claim 4 or claim 5, in which the arcuate end edges are substantially hemispherical and concentrically arranged with respect to a respective location element.

7. The mortise lock assembly according to claim 4 or claim 5, in which the arcuate end edges are of convexly curved configuration

8. A mortise lock assembly for a door, comprising: a casing; a locking mechanism arranged at least partly within the casing and having a latch bolt; a handle, the handle being in operative connection with the latch bolt; a first spring assembly for applying a first return force to the handle; and a second spring assembly for applying a second return force to the handle.

9. The mortise lock assembly according to claim 8, in which the second spring assembly can be activated before the lock is fitted.

10. The mortise lock assembly according to claim 8 or claim 9, in which the second spring assembly includes a pivotably mounted housing.

11. The mortise lock assembly according to any one of claims 8-10, in which the door handle comprises a lever having two lever amis for transmitting a force from the first spring assembly to the latch bolt, and having a further projection which in use cooperates with the second spring assembly.

12. The mortise lock assembly according to any one of claims 8-11, in which a first said lever arm is arranged to act upon a bolt assembly comprising a spring and the latch bolt.

13. The mortise lock assembly according to any one of claims 8-12, in which the second spring assembly is arranged to apply a return force to the handle even when the latter is fully returned to its starting position.

14. A mortise lock assembly for a door, comprising: a casing; a locking mechanism arranged at least partly within the casing; a recess in the exterior of the casing for receiving a sensor module for monitoring the locking mechanism; and a removable module receivable in the recess.

15. The mortise lock assembly according to claim 14, wherein said removable module comprises a sensor module capable of sensing if the locking mechanism is locked or unlocked.

16. The mortise lock assembly according to claim 14 or claim 15, in which the recess is in communication with the interior of the casing.

17. The mortise lock assembly according to any one of the preceding claims 14-16, in which the locking mechanism includes a hook bolt, which in use can be monitored by the sensor module.

18. The mortise lock assembly according to any one of the preceding claims 14-17, wherein said removable module comprises a sensor module capable of sensing if the locking mechanism is locked or unlocked and further comprises a blank module removably receivable in the recess in the exterior of the casing, in which said sensor and blank modules are interchangeable.

19. The mortise lock assembly according to claim 1, further comprising a locking mechanism arranged at least partly within the casing and having a latch bolt; a handle; the handle being in operative connection with the latch bolt; a first spring assembly for applying a first return force to the handle; a second spring assembly for applying a second return force to the handle; a recess in the exterior of the casing for receiving a sensor module for monitoring the locking mechanism; and a removable module receivable in the recess.