Door locks in general are made up of the following functional components; a lock mechanism, a strike or striker plate and so-called"furniture".

The lock mechanism includes the elements that move to secure the door from opening, or allow the door to be unlatched and opened. The lock mechanism is usually mounted to the moving panel. The strike or strike plate is the component that interacts with the lock mechanism e. g. a latch element. The strike plate is commonly fitted to the peripheral framing of the door commonly known as the jamb. The furniture is usually the visual element of the product. It includes the elements that the user interacts with while opening or closing the door. The furniture is mounted on the moving panel.

In some forms of construction the lock mechanism and the furniture fitted onto the inside of the door are combined for

convenience of manufacture and fitment. The functional components still exist within this single assembly however.

Door locks are available in a range of locking options relating to the end use of the door that they are fitted to.

These options include whether the door is to be fitted with a key cylinder on the outside of the panel if the door is to be used as an entry door for the dwelling. Often the internal side of the door lock is actuated with a lever or turn knob.

Alternatively key cylinders can be fitted onto the inside of the door panel if internal security is a concern. A common configuration is that the internal panel is fitted with an actuating lever and a key cylinder. This allows egress from the dwelling with the convenience of a lever or turn knob, but the ability to deadlock the door should the dwelling be un- occupied for any period.

The locking options stated above are well known and commonly specified within the industry. It is common for lock manufacturers to produce all of these options and sell them as individual products. An advantage of the present invention is that it allows the range of locking options discussed above to be produced utilising a common locking mechanism. To configure the door lock to one of the locking options above

alteration to furniture is all that is required. This allows for both manufacturing efficiencies and the possibility of product upgrade in the field.

Because of the"handing"of doors it is known to construct a latching mechanism so that it can be at least partly dismantled for altering the configuration or relative positions of components of the mechanism. In this way the mechanism can be configured so that the snib can, say, always be in the up position when locking irrespective of the handing of the door. The advantage of such a latch mechanism is that the manufacturer can sell the product as a non-handed item.

This means that the manufacturer does not need to stock and sell mechanisms particularly suited for left and right-handed doors.

The removal and altering of components can be fiddly, time consuming and possibly result in the loss or breakage of a component. Consequently, when the latch mechanism is installed the installer may not bother with adjustment of the mechanism to suit the handing of the door to which it is to be fitted.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a latching mechanism which can be configured to suit and use requirements.

Broadly according to one aspect of the invention there is provided a latching mechanism including a housing, a snib rotatably mounted with the housing, two bolt receiving means movable with said snib, a lock bolt, and a selector adjustable to select which of said bolt receiving means will engage with a said lock bolt at a selected locking position of the snib, said locking position corresponding to a locked position of a lockset when latching mechanism is, in use, operatively associated with the lockset.

According to the second broad aspect the invention provides a latching mechanism including a moveable snib, a drive member, coupled to the snib and rotatable by the snib about a first axis, a receiver to receive a tailbar of at least one lock cylinder said receiver being rotatable about a second axis independent of the drive member, and a selector adjustable to move lock bolt between locking position where the snib is

prevented from movement and an unlocking position where the snib is able to be moved.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front perspective view of the latching mechanism, Figure 2 is rear perspective view, Figure 3 is a plan view of the mechanism with the top cover of the housing removed, Figure 4 is an exploded perspective view, Figure 5 is a more detailed illustration of a lock bolt forming part of the mechanism, Figure 6 is a perspective view of the snib, Figure 7 is a bottom perspective exploded view of the snib and associated components of the mechanism,

Figure 8 is a view similar to Figure 7 but from the opposite direction, Figure 9 is a top plan view of the cap portion of the mechanism, and Figure 10 is an underside plan view of the cap.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated the latch mechanism includes a body 10 composed of two parts, namely a bottom housing 11 and a cover housing 12. The cover 12 incorporates four downwardly projecting legs 13 which snap lock through openings 14 in the base 11 when the cover 12 is positioned on the base 11. In the preferred form of the invention the base 11 and cover 12 are moulded from plastic material.

The snib 15 comprises a lever 16 which extends from an annular mounting portion or body 17. The distal end of the lever 16 has a shaped projection 18 which in use would be grasped by the hand of the user in order to manipulate the snib 15.

A drive member or bar 19 fits with the annular mounting portion 17. This drive bar 19 can, according to the preferred form of the invention, be hollow and extruded from an aluminium alloy. It includes a plurality of small longitudinally extending external ribs 20. An end of the drive bar 19 is press fitted into the open centre 21 of body 17. As can be seen in Figure 6 the sidewalls of open centre 21 can have grooves 21a into which ribs 20 engage.

Base 11 has a floor 22 with an opening 23 located substantially centrally in the length of the base 11. Curved walls 24 which are oppositely disposed flank the opening 23.

The substantially disc shaped body 17 can thus fit within the confines of the curved and opposed walls 24 so as to be rotatable about a central axis which is coaxial with the axis of the drive bar 19. Openings 21 and 23 are also co-axially aligned when the snib body 17 is located on floor 22 and between opposed walls 24.

The base 11 further includes a pair of longitudinally extending and opposed channels 25. In each of channels 25 there is slidingly mounted a lock bolt 26. One end of the sliding lock bolt 26 (the end which relative to snib mounting

portion 17 is outermost) has a bore 27 into which one end of a spring 28 is engaged. The other end of the spring 28 engages against a wall or engagement surface 29. The sliding bolt 26 is thus spring biased toward the snib body 17.

Each sliding bolt 26 has on its upper surface a projection 30 which slidingly engages within a cut out 31 in the cover housing 12. The underside of each sliding bolt 26 has a projection 31 which slidingly engages in a cut out 32 in the floor of channel 25. Thus when the sliding bolts 26 have been placed in channels 25 and the cover housing 12 clipped into place the sliding bolts are confined within the body 10 and are firmly retained for sliding movement only in a longitudinal direction relative to the longitudinal axis of symmetry of the body 10.

The channels 25 have open ends adjacent the curved walls 24.

The open end enables the distal end of the sliding bolts 26 to engage with the outer wall surface of snib body 17 as well as a cap 33 as will hereinafter be described.

The cap 33 fits on to the top of the disc shaped body 17. The cap 33 has an inwardly dished portion 34 in the floor of which

is formed an angular opening or slot 35. This cap 33 is accessible via an opening 36 in the cover housing 12.

The mechanism is completed by a drive cap 37. This drive cap 37 includes a shaft 38 which extends within the hollow interior of drive bar 19. A shaped head 39 is formed at one end of the shaft 38. Head 39 engages within the confines of the body 17 as enclosed by cap 33. Extending through head 39 and into shaft 38 is an angular receiving area or slot 40 which aligns with slot 35 in cap 33. Extending in from the other end of the shaft 38 is a further angular receiving area or slot 41. Slots 40 and 41 do not meet.

Referring more particularly to Figure 5, the distal end 42 of sliding bolt 26 is of a shaped form which in use engages against the outer wall surface or peripheral rim 43 of body 17 and the circumferential edge 44 of cap 34. End portion 42 includes a curved nose 45 and a square or angular nose 46.

These respectively engage against rim 43 and edge 44.

As can be seen from Figure 6, peripheral rim 43 of body 17 has two cut outs 47. Each cut out 47 is shaped such that angular nose 46 can fit therein as hereinafter will be described.

These cut outs 47 are located at two deadlocking positions the snib can adopt as will also be described hereinafter.

Similarly circumferential edge 44 of cap 33 has three curved recesses 48 and 49 with which curved nose 45 can engage as will hereinafter be described.

Cap 33 and head 39 are mechanically coupled. In the preferred form a pair of spigots 50 projecting from the underside of dish portion 34 of cap 33 engage with a pair of correspondingly spaced and positioned recesses 50 in head 39.

As can be seen from Figures 4,7 and 8 the head 39 has a pair of rebates 53. As shown in Figure 6, the body 17 of snib 15 includes a spigot 54 within the well of the dish shape. This spigot 54 and rebates 53 interengage as will hereinafter be described.

The primary function of the latching mechanism is to enable a user to operate (lock and unlock) a mortice (or instile) sliding door lock with either the snib or a key. The mortice sliding door lockset can be of the type described in New Zealand patent specification 301389. The latching mechanism

according to the present invention enables the user to deadlock the lockset (via a key) by deadlocking the snib 15.

In use the latching mechanism according to the present invention by being a stand-alone assembly can be concealed within the confines of the mortice lockset furniture which will be surface mounted on the stile of the door. A 5-pin lock cylinder incorporated in the lock furniture has its operating tongue or tailbar positioned through opening 36 and via slot 35 into slot 40 in shaft 38. The drive bar 19 extends into the lockset to interengage with the driven member of the mortice lockset in a conventional manner.

If required the tailbar of a lock cylinder positioned on the other side of the door to which the latching mechanism is located can engage through the lockset and into slot 41 of shaft 38. Consequently, a locking cylinder can be provided on both sides of the door with which the lockset is installed.

In use the snib 15 can be moved between its two extreme positions of movement in order to affect a simple latching function. Because the snib 15 is not physically coupled to cap 33 it can be operated to simply rotate drive shaft 19

which will cause the mortice lock to move to a latching position or to an unlatching position as the case may be.

However, if a key is inserted in the lock cylinder and rotated the tailbar of the lock cylinder due to its interengagement in slot 40 rotates the shaft 38. This will cause one of the rebates 53 to come into engagement with the spigot 54 which will cause the snib 15 to move from one extreme position of rotation to the other.

In conjunction with the rotation of shaft 38 cap 33 will also rotate (because the drive tongue engages through slot 35 of cap 33) whereby the locking recess 49 will interengage with nose 45 of the sliding bolt 26 which becomes aligned with recess 49. The angular nose 46 will thus move into the aligned cut out 47 of the mounting portion 17. The snib will thus be deadlocked.

Reverse movement of the head 39 which is necessary as a result of reverse movement of the key in the key cylinder (to enable the key to be removed) is possible due to the degree of lost motion (see Figure 10) which exists because of the manner in which the head 39 interengages with spigot 54.

Because the mounting portion 17 has two cut outs 47 the one which is used to carry out the deadlocking function is determined by the orientation that the installer sets the snib 15 to correspond to the locking position of the mortice lock.

The installer then engages the drive bar 19 into the mortice lock thereby configuring the handing of the mechanism.

Thus irrespective of the orientation of the mortice lock (dependant on the handing of the door or the position in which the mortice lock is installed) the installer can position the snib 15 to say an up position corresponding to the lockset being in the locked position. A colour (usually red) indicator 55 can then be snap fitted into waisted area 56 on the desired side of lever 16 to be visible when the mortice lock is in the unlocked position. Figure 3 shows the snib 15 in a locked position hence the indicator is not totally visible.

The latching mechanism according to the present invention thus provides an installer the ability to configure the lockset and lock snib to be in the locked position with the snib in a selected position (either up or down) without the need to

remove or alter any components. This function is achieved during the fitment of the lock and furniture to the door stile. Accordingly, the latching mechanism can be sold in a non-handed fashion.

Also the latching mechanism enables lockset furniture to be altered such that key lockable cylinders can be employed on either side of a door in which the lockset is located.