NZ746323A - Mortice latch assembly - Google Patents

Abstract

This invention relates to a mortice latch assembly 1 for mounting to a door 6 including a first hub 12 and a second hub 10 which are each operable to retract a bolt 33. The mortice latch assembly 1 also includes a lock mechanism including a detent 72 which takes the form of an elongate member. The detent is adjustable relative to the housing 8 between a first position and a second position. The detent 74 is also rotatable about its longitudinal axis between a first active position and a second active position.

Description

MORTICE LATCH ASSEMBLY Technical Field This invention relates to a mortice latch assembly for installation in a door including a first hub and a second hub to move a bolt, a lock mechanism including a detent that is adjustable between a first active position and a second active position, so that the detent inhibits operation of the first hub or second hub respectively. The mortice latch assembly provides a relatively simple option for a residential security application and it will be convenient to hereinafter describe the invention with reference to this application. It should be appreciated however that the mortice latch assembly may have other applications.

Background of Invention The lock security market can be segmented into various sections including residential or commercial, and those sections can each be further segmented into high or low security. The challenge for the operators, including the applicant, in the security market is to supply security options at a price that will be acceptable. While the high security commercial segment may accommodate a relatively high price for a security option, the low security residential segment is much more price sensitive.

A further challenge for those mature operators that have a range of security options, is attempting to create new security options that don’t overlap with existing security options in such a way as to cannibalise the market for the existing security options. More specifically it is preferable for mature operators to avoid supplying a low cost security option which facilitates after-market modifications, say by the retailer or installer, to suit a high security high cost option.

The residential segment of the security market can include both houses and apartments. Apartments can require high security options for say at the external access points to the building which might be maintained by the body corporate or building manager. Whereas a relatively low security option may be all that is required or expected for the for the access point to the apartment itself as selected or maintained by the resident. <filename> One security option selected by residents of apartments includes a latch assembly that when installed has the first hub is set to escape mode, while the second hub remains lockable. The first hub would normally be operable from the inside of the door, which the second hub would be operable from the outer side of the door. This particular application can be found on locks installed on the front door of apartments particularly where it is the only access point from within the building itself to the apartment. It should be appreciated however, that depending on whether the door is right-hand opening or left-hand opening, will dictate which hub is the first hub and second hub respectively. Furthermore, depending on whether the apartment door is inward opening or outward opening, left-hand opening or right-hand opening, will dictate the slope of the bevelled leading surface of the latch bolt head. The challenge for operators is supplying security options to satisfy these different installations. It will be convenient to hereinafter describe the invention with reference to this application.

A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was, in Australia, known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.

Summary of Invention According to this invention there is provided a mortice latch assembly for mounting in a door, including a housing, a bolt movable relative to the housing between an extended position and a retracted position, an actuator including a first hub and a second hub for operation from an inner side and an outer side respectively of the door to move the bolt from the extended position to the retracted position, a lock mechanism including a detent that is adjustable relative to the housing between a first position and a second position so that in the first position the detent does not inhibit operation of either the first hub or second hub, and also adjustable between a first active position and a second active position so that when in the second position the detent inhibits operation of the first hub or second hub respectively, wherein the housing includes a front wall formed of mild steel, having an arm projecting towards a body portion of the bolt, and including a faceplate formed of stainless steel that overlies and extends parallel to the front wall of the housing. This arrangement is <filename> particularly suitable where the base is formed from a cast zinc alloy, as the mild steel can maintain its integrity in supporting the bolt when the mortice lock is exposed to high temperatures.

It is preferred that when in the second position the detent inhibits operation of the first hub only or second hub only when in the first active position and second active position respectively. This simplifies the componentry of the mortice lock and reduces the overlap with existing security options. It is further preferred that the housing is configured to permit adjustment of the detent between the first active position and the second active position when in the first position. This arrangement reduces the ability for the lock mechanism to be circumvented when mortice latch assembly is installed. It is further preferred that the housing includes a base and a cover which is fastened to the base, with the base and or cover including an aperture providing the housing with said configuration through which the detent may be adjusted between the first active position and the second active position when the detent is in the first position and the cover is fastened to the base. It is often desirable for a housing to be formed from components such as a base and a cover, and allowing the adjustment of the detent while the housing remains assembled contributes to having a simple installation process. The aperture may be located anywhere on the housing, and one option is for the aperture to extend from the cover to a rear wall of the base only. However the aperture may be located entirely on the cover, or may be entirely located on the base.

The mortice latch assembly preferably includes a deadlatching mechanism with an abutment that in an active position inhibits movement of the bolt from the extended position to a retracted position and in an inactive position does not inhibit movement of the bolt from the extended position to a retracted position, and an auxiliary bolt that is movable in a direction parallel with the bolt between an extended position and a retracted position, the auxiliary bolt including an arm portion that engages the abutment when the auxiliary bolt is in the extended position to retain the abutment in an inactive position. This arrangement reduces the ability for the bolt of the mortice latch assembly to be tampered with while the door is closed. The abutment preferably includes an abutment member that is formed from a non-ferrous metal. The use of a non-ferrous metal for the abutment member makes it more difficult for tampering with the deadlatch mechanism by magnetic forces when the <filename> mortice latch assembly is installed. The abutment member may move within the housing in any suitable manner and one arrangement includes the abutment member pivoting relative to the housing between the active position and the inactive position.

However the abutment member may, for example, slide linearly relative to the housing. The arm portion of the auxiliary bolt may move rectilinearly relative to the housing when the auxiliary bolt moves between the extended position and the retracted position. This preferred arrangement can be achieved where the arm portion is formed integrally with a body portion of the auxiliary bolt, which in turn creates efficiencies in the manufacture of the latch bolt assembly. It is preferred that the deadlatching mechanism include an auxiliary biasing member for biasing the auxiliary bolt towards the extended position. The biasing member may take any suitable form including a spring. The deadlatching mechanism may also include an abutment biasing member for biasing the abutment towards the active position.

The detent is preferably configured to interact with the housing so as to slide linearly between the first position and the second position. It is further preferred that the detent be configured to interact with the housing so as to rotate about a longitudinal axis of the detent when adjusting between the first active position and the second active position. This arrangement allows the detent to be formed as a unitary member which is relatively simple from a manufacturing perspective. It is further preferred that the mortice latch assembly include a bi-stable arrangement which urges the detent to adopt either the first active position or second active position. It is further preferred that the bi-stable arrangement includes a detent biasing member which engages the detent, with the detent shaped so that rotation of the detent through no more than 45º causes the detent biasing member to store potential energy. This arrangement reduces the likelihood of the detent inadvertently adjusting, or unauthorised manipulation occurring. It is further preferred that the detent biasing member also urges the detent to adopt either the first position or the second position.

It is further preferred that the bolt include a bolt head and a bolt body, the orientation of the bolt head relative to the bolt body being adjustable by rotation through 180º.

According to another aspect of this invention there is provided a lockset for mounting to a door including a mortice latch assembly as hereinbefore defined, an <filename> inner handle assembly and an outer handle assembly each being operable to from an inner side and outer side of the door for interaction with the first hub and second hub respectively. It is preferred that the lockset include at least an outer cylinder lock being operable from an outer side of the door for interaction with the lock mechanism of the mortice latch assembly.

Brief Description of Drawings It will be convenient to hereinafter describe the invention with greater detail by reference to the attached illustrations. The attached illustrations show preferred embodiments of the invention. The drawings, and the following detailed description, are merely illustrative of how the invention might be put into effect. The specific form and arrangement of the various features as shown is not to be understood as limiting on the invention.

Detailed Description of Drawings Future patent applications may be filed in Australia or overseas on the basis of or claiming priority from the present application. It is to be understood that the following provisional claims are provided by way of example only, and are not intended to limit the scope of what may be claimed in any such future application.

Features may be added to or omitted from the provisional claims at a later date so as to further define or re-define the invention.

Figure 1 is an isometric partially exploded view of a lockset according to one aspect of this invention.

Figure 2 is an exploded isometric view of a mortice latch assembly according to another aspect of this invention.

Figure 3 is a side elevation view of the mortice latch assembly with a cover removed, and the bolt in an extended position.

Figure 4 is a side elevation view of the mortice latch assembly from Figure 3 with a second hub rotated to move the bolt to a retracted position.

Figure 5 is a side elevation view of the mortice latch assembly from Figure 3 with a detent of a lock mechanism shown in a second position. <filename> Figure 6 is a side elevation view of the mortice latch assembly from Figure 3 with the detent shown in a first position and in a first active position.

Figure 7 is a side elevation view of the mortice latch assembly from Figure 6 adjusted to show the detent now in a second position and first active position with the second hub rotated to move the latch bolt to a retracted position.

Figure 8 illustrates a rear isometric view of the mortice latch assembly showing a pin engaging the detent.

Figure 9 is a rear isometric view of the mortice latch assembly from Figure 8 with the detent rotated through 90 .

Figure 10 is a side elevation view of the mortice latch assembly from Figure 3 showing the auxiliary bolt in an extended position.

Referring now to Figure 1 which illustrates the preferred embodiment of the lockset according to one aspect of the invention which in summary includes a mortice latch assembly 1, an inner handle assembly 2, an inner cylinder lock assembly 3 and an outer cylinder lock assembly 4, and an outer handle assembly 5 for all of which is configured for mounting to a door 6. The selection of the terms "inner" and "outer" relate to an inner side and an outer side of the door. Figure 1 illustrates the door 6 being formed with a rectangular void 7 in a side edge thereof for accommodating the housing 8 of the mortice latch assembly 1.

The door 6 is also illustrated as having a circular aperture 9 formed on an outer surface thereof through which an outer spindle (obscured) of the outer handle assembly 5 extends to engage a second hub 10 of the mortice latch assembly 1. An equivalent circular aperture (obscured) would also be formed on an inner surface of the door 6 for accommodating an inner spindle 11 of the inner handle assembly 2 which engages a first hub 12 (see Figure 2) of the mortice latch assembly 1. The inner surface and outer surface of the door 6 would also require a pair of holes 13 bored on either side of the inner circular aperture 9 and outer circular aperture for accommodating the pair of studs 14 and screws 15 extending from a rear of the inner escutcheon 16 and outer escutcheon 17 respectively. Figure 1 also illustrates an oval shape aperture 18 formed in an outer surface of the door 16 to allow an outer cylinder <filename> lock housing 19 to extend therethrough. An equivalent oval shaped aperture (obscured) is formed on an inner surface of the door 6 for accommodating an inner cylinder lock housing 20 therein. Each of the inner cylinder lock housing 20 and the outer cylinder lock housing 19 are surrounded by an inner escutcheon 21 and an outer escutcheon 22 respectively which are attached to each other by screw fasteners 23. Furthermore, each of the inner cylinder lock housing 20 and outer cylinder lock housing 19 extend into the housing 8 through a respective oval shaped aperture 24 (only the outer oval shaped aperture is visible in Figure 1) for interaction with a lock mechanism (obscured) which will be described in greater detail with reference to latter illustrations.

The mortice latch assembly 1 is illustrated in an exploded view in Figure 2 to reveal the housing 8 is formed from a base 25, a cover 20, and a front wall 27. The cover 26 can be positioned over the base 25 and attached thereto by way of four screw fasteners 28. Furthermore, the front wall 27 can be attached to mounting formations 29 formed on the base 25 by a pair of screw fasteners 30. Figure 2 also illustrates a face plate 31 which can be positioned to overly the front wall 27 and attached thereto by a pair of screw fasteners 32. While the base 25 and the cover 26 may be formed from any suitable material, the applicant has appreciated that there is a perception of quality in the marketplace when these components are cast from a zinc alloy. The face plate 31 may also be formed from any suitable material however, it is preferred that it is formed from a stainless steel as this enhances the appearance of the lock when installed, while being relatively resistant to malicious attack by a drill or the like. The front wall 27 of the housing may also be formed from any suitable material however, for reasons that will be explained later in the specification it is preferred that it be formed from a relatively fire resistant material such as mild steel.

The bolt 33 as illustrated in Figure 2 is in the form of a bolt assembly which in summary includes a latch bolt head 34, a body 35, a shaft 36 and a bolt biasing spring 37. When the latch bolt assembly is assembled, the shaft 36 extends through the centre of the biasing spring 37 so as to support and guide the spring 37 while the bolt moves from an extended position to a retracted position. More specifically, the shaft 36 inhibits the ability of the spring 37 to deviate from its central axis when compressing. A distal end of the shaft 36 is located within a bore 38 formed in a cylindrical boss at the rear surface of the latch bolt head 34. The cylindrical boss 39 <filename> extends into an aperture (obscured in the drawings) formed at a distal end 40 of the body 35. This arrangement allows the orientation of the latch bolt head 34 to be adjusted through 180 relative to the body 35 so that the mortice latch assembly is suitable for installation in either a right-hand opening door, a left-hand opening door, an inwardly opening door or an outwardly opening door.

The shape of the latch bolt head 34 relative to the size of the opening 41 in the front wall 27 is designed to allow the orientation of the latch bolt head 34 to be adjusted without having to disassemble the housing 8. However, the shape of the latch bolt head 34 relative to the opening 42 in the face plate 31 is designed to inhibit rotation of the latch bolt head 34 whilst the face plate 31 is attached to the front wall 27. This arrangement inhibits tampering of the orientation of the latch bolt head 34 relative to the housing 8 particularly when the mortice latch assembly 1 is installed.

Figure 2 illustrates the first hub 12 and the second hub 10 which form part of an actuator for moving the latch bolt from an extended position to a retracted position. Both the first hub 12 and second hub 10 include a circular boss 43 (the boss 43 of the first hub is obscured in Figure 1) which locates in a circular aperture 44, 45 formed in the base 25 and cover 26 respectively, so as to allow the first hub 12 and second hub 10 to rotate about an actuator axis X-X. The actuator illustrated also includes a washer 46 acting as a bearing surface between the first hub 12 and second hub 10, so as to reduce the likelihood of rotation of either the first hub 12 or second hub 10 will result in rotation of the second hub 10 or first hub 12 respectively.

Both of the first hub 12 and second hub 10 include an upper arm 47 which is for engagement behind a proximal end 49 of the latch bolt body 35 so as to provide a direct engagement therebetween. Alternatively the actuator may include an intermediate arm (not shown) between a first hub 12 and second hub 10 by providing indirect engagement between the first hub 12 and second hub 10 and the latch bolt assembly 37.

Each of the first hub 12 and second hub 10 includes a lower leg 50, 51 which is for abutting a hub return arrangement for urging each of the first hub 12 and second hub 10 towards a rest position. The hub return arrangement may take any suitable form and in the embodiment illustrated in Figure 2 includes a bar 52 and compression spring 53 which compresses on rotation of either the first hub 12 or <filename> second hub 10. This operation of the hub return arrangement will be descried in greater detail later in the specification. Clearly other arrangements are possible such as torsion spring acting between either the first hub 12 or second hub 10 with the base 25 and cover 26 respectively. However, the illustrated arrangement is preferred as it is relatively simple to assemble.

The mortice latch assembly 1 illustrated in Figure 2 also includes a deadlatching mechanism that when operable inhibits movement of the latch bolt 33 from the extended position that may be achieved by applying end pressure to the latch bolt head 34. The operation of the detent mechanism will be described in greater detail by reference to the latter illustrations, however from Figure 2 it can be appreciated that the deadlatching mechanism includes an abutment 54 having an aperture 55 therein for mounting to a stub shaft 56 formed on an inner surface of the base 25. This allows the abutment 55 to pivot about the stub shaft 56, while a torsion spring 57 is included to urge the abutment 54 to pivot towards an active position. The deadlatching mechanism also includes an auxiliary bolt 58 having an auxiliary bolt head 59 for extending through a slot 60 in the front wall 27 and a slot 61 in the face plate 61. The auxiliary bolt 58 is urged towards an extended position under the action of an auxiliary bolt biasing spring 62 acting between the auxiliary bolt 58 and the base . The auxiliary bolt 58 includes an arm portion 63 that is formed integrally with the auxiliary bolt head 59, with the arm portion 63 being arranged to engage the abutment 54 when the auxiliary bolt head 59 is in the extended position. The deadlatching mechanism also includes a hub release member 64 having a bore 65 formed therein for receiving a stub shaft 66 formed on an inner surface of the base 25, so as to permit the hub release member 64 to pivot thereabouts. The hub release member 64 includes an upper arm 67 and a lower arm 68 angularly spaced from one another.

The lower arm 68 is for engagement with a shoulder 69, 70 formed on both the first hub 12 and second hub 10 respectively, whilst the upper arm 67 is for engagement with a lower leg 71 of the abutment 54. This interaction will be described in greater detail with reference to latter illustrations.

The mortice latch assembly 1 illustrated in Figure 2 also includes a detent 72 which forms part of a lock mechanism which is illustrated in the form of an elongate member. The detent 72 includes cylindrical central portion 73 which is received in a semi-cylindrical recess 74 formed on an inner surface of the base 25. <filename> The body portion 73 is intended to slide within this recess 74 and guide the detent 72 as it moves relatively to the housing 8. This movement will be described in greater detail with reference to latter illustrations.

The detent 72 illustrated in Figure 3 includes an upper portion which is formed by a pair of spaced shoulders 75, 76 which are shaped and spaced to permit interaction with a cam plate 77 in a manner that will be described during the specification. A lower end of the detent 72 includes a formation that is configured to interact with either the first hub 12 or the second hub 10 only depending on the orientation of the detent 72 relative to the housing 8. A preferred arrangement illustrated includes a pair of walls which extend perpendicular relative to each other to form a corner, with only one of the walls being visible in Figure 2 and 3, while the other wall can be appreciated with reference to Figure 6. This arrangement can clearly take other physical forms other than a pair of walls.

The detent 72 illustrated in Figure 2 also includes an upper annular lower groove 80 and a lower annular groove 81 spaced by an irregular octagon 82 (see Figure 3). The detent 72 includes an upper socket 83 and a lower socket 84 (see figure 5) that projects towards each other into the upper groove and lower groove respectively. Each of the upper socket 83 and lower socket 84 each interact with a detent biasing member 85 to create a bi-stable arrangement that will be described later in the specification. It should be appreciated in Figure 2 however that the detent biasing member 85 is formed from spring steel having a pair of opposed arms. Each of the opposed arms includes a projection formed on an inner surface thereof adjacent respective free ends. It ought to be appreciated that as the detent biasing member 85 is formed from spring steel any flexing of the arms away from the position as illustrated in Figure 2 will cause the detent biasing member to absorb potential energy.

It should also be noted from Figure 3 that the detent 72 is formed with a small bore 86 located adjacent the lower end thereof. The bore 86 can be aligned with a groove 87 formed in a rear wall of the base 25, and with a groove 88 formed adjacent an edge of the cover 26. This groove arrangement provides access to the bore 86 whilst the housing 8 in assembled for reasons that will be explained later in the specification. <filename> Referring now to Figure 3 which illustrates the mortice latch assembly without the cover and latch bolt assembly body to reveal the deadlatching mechanism with the abutment 54 in an active position. When the abutment 54 is in the active position an upper arm 89 thereof is positioned between the latch bolt head 34 and the stub shaft 56 inhibiting retraction of the latch bolt 33. It should also be noted from Figure 3 that the auxiliary bolt 58 is in a retracted position so that the arm portion 63 thereof is disengaged from the upper arm 89 of the abutment 54. As a result the abutment 54 is free to rotate about the stub shaft 56 under the influence of the torsion spring 57, but only so far as would be allowed until the lower arm 71 of the abutment 54 engages an upper arm 67 of the hub release member 64. The hub release member 64 is in turn prevented from rotating by its engagement with either the first hub 12 or second hub 10, each of which are prevented from rotating an anti-clockwise direction from the position illustrated in Figure 3 by engagement with a rear wall of the housing.

Figure 3 also illustrates a support portion 90 of the front wall 22 which extends up towards the shaft 36 of the latch bolt assembly. It can be appreciated from Figure 2 that this support portion 90 is folded out from the front wall 27 and so is formed integrally therewith. Where the front wall 27, and in particular the support portion 90 is formed from a relatively fire resistant material, in conjunction with the shaft 33 and the latch bolt head 34 are also formed from a fire resistant material, the applicant has appreciated that the mortice latch assembly 1 can maintain some level of integrity in the event of a fire. As indicated previously, it is preferred that the front wall 27, and in particular the support portion 90 are formed by a mild steel.

Figure 3 illustrates the second hub 10, and it ought to be appreciated that the first hub 12 is positioned behind the second hub in this view. Furthermore, the detent 72 is illustrated in a raised, or hereinafter a first position, within the housing 8.

The rotational position of the cylinder cam 72 should be noted whereby the cylinder cam 72 is engaging an upper shoulder 75 at of the detent. Furthermore, the detent biasing member 85 is seated within the lower groove 81 of the detent 72 so as to inhibit unauthorised movement of the detent from this first position. Furthermore, it should be noted that the bar 57 of the hub biasing arrangement is engaging the lower leg 51 of the second hub 10 and first hub 12 (obscured) under the influence of the hub biasing spring 53. <filename> Turning now to Figure 4 we note that the second hub 10 has been rotated in a clockwise direction. The lower arm 51 of the second hub 10 has moved the bar 52 of the hub biasing arrangement towards the front wall 27 of the housing thereby compressing the hub biasing spring 53. Rotation of the second hub 10 has also caused relative movement of the shoulder 70 relative to the hub release member 65 causing it to rotate in an anti-clockwise direction about the stub shaft 66. This has in turn caused the abutment 54 to rotate in a clockwise direction about its stub shaft 66 raising the upper arm 89 away from the rear of the latch bolt head 34. With the upper arm 89 in the raised position, the upper arm 48 of the second hub 10 can engage the proximal end 49 of the latch bolt assembly body 35. As a result of the rotation of the second hub 10 in a clockwise direction, the latch bolt assembly 33 is moved to the retracted position. It should be noted that this rotation of the second hub 10 is permitted as a result of the position of the detent 72 within the housing, and in particular the lower end of the detent 72 being spaced from the second hub 10.

Turning now to Figure 5 which has had the latch bolt assembly body removed for ease of understanding, it can be noted that the cylinder cam 77 has been rotated through 90 so that it engages a lower shoulder 76 at the upper end of the detent 72. The rotation of the cam 77 has caused the detent 72 to move axially from the first position as illustrated in Figure 4, to a second position as illustrated in Figure . In order to achieve this move the protrusion of the detent biasing member 85 needs to unseat from the lower groove 81, move across the ridge formed by the irregular octagon 82 to seat within the upper groove 80. It is preferred that the shape of the protrusion on the detent biasing member 85 relative to the shape of the ridge of the irregular octagon 82 is such that movement of this type is bi-stable so that the detent 72 is urged to adopt either the first or second position.

Figure 5 also illustrates the lower end of the detent 72 being positioned relative to the second hub 10 so as to inhibit its rotation in the clockwise direction.

Whilst it is not apparent from Figure 5, the lower end of the detent is only preventing rotation of the second hub 10, the lower end of the detent 72 as explained previously, includes a pair of perpendicular walls 78, 79 so that whilst one of the perpendicular walls 78 as illustrated in Figure 5 is preventing rotation of the second hub 10, the other perpendicular wall 79 extending into the page is not positioned to prevent rotation of the first hub 12. The detent 72 can be rotated about its longitudinal axis, <filename> however this cannot be achieved whilst the detent 72 is in the second position as illustrated in Figure 5. As the bore 86 is not aligned with the groove 87, 88 in the second position.

Figure 6 illustrates the detent 72 having been returned to the first position, and once in this position the detent 72 can be rotated about its longitudinal axis.

Figure 6 also reveals now the other perpendicular wall 79, with the first perpendicular wall 78 now extending out of the page. It ought to be appreciated that with the detent 72 in this rotational position, returning the detent to the second position as illustrated in Figure 7, rotation of the first hub 12 would be prevented whilst rotation of the second hub 10 would be permitted. This rotation of the detent 72 can only be achieved whilst in the first position It can be appreciated when comparing Figures 8 and 9 that a pin 91, such as the pin that may be used to secure the cylinder lock 19, 20 to the housing 8 can be temporarily inserted through the slot 87, 88 in the base 25 or lever 26 to engage the bore 86 in the detent 72. The detent 72 can thereafter be rotated so as to adjust between the first active position and the second active position.

Referring now to Figure 10 which illustrates the latch bolt assembly body and part of the abutment 54 in dashed line, and it can be noted that the auxiliary bolt 58 is in the extended position. With the auxiliary bolt 58 in the extended position, such as may be the case when the door is open, the arm portion 63 of the auxiliary bolt 58 engages with the upper arm 89 of the abutment. This engagement captures and raises the upper arm 89 causing the abutment 54 to pivot in a clockwise direction about the stub shaft 56 to thereby move the upper arm 89 away from the rear wall of the latch bolt head 34. It ought to be appreciated that the arrangement of the abutment 54, the latch bolt 33 and the auxiliary bolt 58 will allow the latch bolt head 34 and the auxiliary bolt head to engage a strike (not shown) and allow automatic latching of the mortice latch assembly 1.

It ought to be appreciated from the foregoing that the mortice latch assembly 1 as hereinbefore described provides a relatively simple option for a residential security application. The ease and ability to adjust the orientation of the latch bolt head 34 relative to the latch bolt body 35, in conjunction with adjustment of <filename> the detent between the first active position and second active position whilst the housing 8 remains assembled would provide a particular benefit to those installing the lock. Furthermore, the use of non-ferrous materials in the abutment facilitate an inhibiting unauthorised manipulation thereof.

Various alterations and/or additions maybe introduced into the mortice latch assembly as hereinbefore described without departing from the spirit or ambit of the invention. <filename>

Claims (19)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A mortice latch assembly for mounting in a door, including a housing, a bolt movable relative to the housing between an extended position and a retracted position, an actuator including a first hub and a second hub for operation from an inner side and an outer side respectively of the door to move the bolt from the extended position to the retracted position, a lock mechanism including a detent that is adjustable relative to the housing between a first position and a second position so that in the first position the detent does not inhibit operation of either the first hub or second hub, and also adjustable between a first active position and a second active position so that when in the second position the detent inhibits operation of the first hub or second hub respectively, wherein the housing includes a front wall formed of mild steel, having an arm projecting towards a body portion of the bolt, and including a faceplate formed of stainless steel that overlies and extends parallel to the front wall of the housing .

2. A mortice latch assembly according to claim 1 wherein when in the second position the detent inhibits operation of the first hub only or second hub only when in the first active position and second active position respectively.

3. A mortice latch assembly according to claim 1 or 2 wherein the housing is configured to permit adjustment of the detent between the first active position and the second active position when in the first position.

4. A mortice latch assembly according to claim 3 wherein the housing includes a base and a cover which is fastened to the base, with the base and or cover including an aperture providing the housing with said configuration through which the detent may be adjusted between the first active position and the second active position when the detent is in the first position and the cover is fastened to the base.

5. A mortice latch assembly according to claim 4 wherein the aperture extends from the cover to a rear wall of the base only.

6. A mortice latch assembly according to any one of the preceding claims including a deadlatching mechanism having an abutment that in an active position inhibits movement of the bolt from the extended position to a retracted position and in <filename> an inactive position does not inhibit movement of the bolt from the extended position to a retracted position, and an auxiliary bolt that is movable in a direction parallel with the bolt between an extended position and a retracted position, the auxiliary bolt including an arm portion that engages the abutment when the auxiliary bolt is in the extended position to retain the abutment in an inactive position.

7. A mortice latch assembly according to claim 6 wherein the abutment includes an abutment member that is formed from a non-ferrous metal.

8. A mortice latch assembly according to claim 7 wherein the abutment member pivots relative to the housing between the active position and the inactive position.

9. A mortice latch assembly according to any one of claims 6 to 8 wherein the arm portion of the auxiliary bolt moves rectilinearly relative to the housing when the auxiliary bolt moves between the extended position and the retracted position.

10. A mortice latch assembly according to any one of claims 6 to 9 including an auxiliary biasing member for biasing the auxiliary bolt towards the extended position.

11. A mortice latch assembly according to any one of claims 6 to 10 including an abutment biasing member for biasing the abutment towards the active position.

12. A mortice latch assembly according to any one of the preceding claims wherein the detent is configured to interact with the housing so as to slide linearly between the first position and the second position.

13. A mortice latch assembly according to any one of the preceding claims wherein the detent is configured to interact with the housing so as to rotate about a longitudinal axis of the detent when adjusting between the first active position and the second active position.

14. A mortice latch assembly according to claim 13 including a bi-stable arrangement which urges the detent to adopt either the first active position or second active position.

15. A mortice latch assembly according to claim 14 wherein the bi-stable arrangement includes a detent biasing member which engages the detent, with the <filename> detent shaped so that rotation of the detent through no more than 45º causes the detent biasing member to store potential energy.

16. A mortice latch assembly according to claim 15 wherein the detent biasing member also urges the detent to adopt either the first position or the second position.

17. A mortice latch assembly according to any one of the preceding claims wherein the bolt includes a bolt head and a bolt body, the orientation of the bolt head relative to the bolt body being adjustable by rotation through 180º.

18. A lockset for mounting to a door including a mortice latch assembly according to any one of the preceding claims, an inner handle assembly and an outer handle assembly each being operable to from an inner side and outer side of the door for interaction with the first hub and second hub respectively.

19. A lockset according to claim 18 including at least an outer cylinder lock being operable from an outer side of the door for interaction with the lock mechanism of the mortice latch assembly. <filename>