EP4692494A1

EP4692494A1 - Night latch assembly

Info

Publication number: EP4692494A1
Application number: EP25192885.9A
Authority: EP
Inventors: Bruce Mccarthy
Original assignee: Assa Abloy Ltd
Current assignee: Assa Abloy Ltd
Priority date: 2024-08-09
Filing date: 2025-07-30
Publication date: 2026-02-11
Also published as: GB202411821D0; GB2643320A

Abstract

A night latch assembly (6) comprises a cylinder assembly (22), a lock case assembly (26) and a mounting plate (24). The cylinder assembly (22) and mounting plate (24) have mutually co-operative attachment structures (32, 34, 56, 58) by which they are attachable to one another. The lock case assembly (26) and mounting plate (24) do not have mutually co-operative attachment structures by which they are attachable to one another. The lock case assembly (26) has an attachment structure (72) configured for attachment of the lock case assembly (26) to a door (2).

Description

Field of the Invention

The present invention concerns night latches. More particularly, but not exclusively, the invention concerns a night latch assembly with a mounting plate used for fitting the night latch assembly to a door. The invention also concerns a mounting plate for such a night latch assembly, a method of fitting a night latch assembly to a door, and a door having a night latch assembly.

Background of the Invention

A night latch is a type of door lock which in use has a cylinder assembly on one face of a door, and a lock case assembly on an opposite face of the door. Generally, the lock case assembly is positioned on the face of the door which faces into a building or room, and the cylinder assembly is positioned on the face of the door which faces out from the building or room. The cylinder assembly usually has a lock cylinder which can be rotated by a key. The lock case assembly usually has a bolt which is receivable in a keep mounted to the frame of the door, and a handle that can be rotated by hand so as to retract the bolt.
Generally, the lock cylinder has a tail bar which is received in an aperture in the lock case assembly and couples the lock cylinder to the handle such that the bolt can be retracted by rotating either one. Thus, a person can pass through the door in one direction (for instance leaving the room or building) simply by rotating the handle, but to pass in the opposite direction (for instance entering the room or building) they must operate the lock cylinder using a key.
Conventional night latches are usually fitted to a door using a mounting plate as follows. A relatively large hole (normally 32mm in diameter) is drilled through the door near its edge, through both faces. The cylinder assembly and mounting plate are presented to opposite faces of the door, held in their required positions on the door, with the tail bar extending from the cylinder assembly through an aperture in the mounting plate. They are then attached together using screws which run through the hole. Tightening the screws clasps the door between the cylinder assembly and mounting plate, holding those components in position.
With the cylinder assembly and mounting plate in position, the lock case assembly is presented to the side of the door, over the top of the mounting plate. The tail bar of the cylinder assembly is aligned with a corresponding aperture in a rear face of the lock case assembly, and then the lock case assembly is placed on top of the mounting plate. Projections extending forward from a front face of the mounting plate are received in corresponding recesses in a rear face. The function of the night latch can then be tested to ensure that all the components are in the right location and orientation.
If the cylinder assembly, mounting plate and lock case assembly are all correctly positioned, the lock case assembly is removed from the mounting plate and the mounting plate is screwed to the door. The lock case assembly is then replaced and screwed to the mounting plate by screws which pass through threaded holes in one or more of the projections.
There are numerous problems with such conventional designs and methods of fitting. For example, fitting the night latch to a door can be very fiddly in terms of positioning each component and ensuring it does not move from that position. Firstly, to attach the cylinder assembly and mounting plate to one another requires them to be positioned on opposite sides of the door with respective screw holes (which are hidden from view) aligned, then held there while a screw is inserted through those holes and then driven home with a screwdriver. This requires significant dexterity on the part of the fitter, and/or multiple attempts. Secondly, with those components attached together the screws must be tightened so that the door is clasped between them and they cannot move. This can be problematic, particularly when tightening the first screw where the torsion applied to the screw can be transmitted to the cylinder assembly and cause it to rotate out of position.
Also, while securing the cylinder assembly and mounting plate, the mounting plate must be located in a position at which the lock case assembly, when attached thereto, will positioned correctly (i.e. spaced the correct distance from the edge of the door, at the right height up the door, with the bolt running horizontally). Whilst this is simple in theory, in practice it often requires a degree of trial and error with the lock case assembly being placed onto the mounting plate, checked, removed so that the mounting plate position can be loosened and adjusted, replaced for re-checking, and so on. Each time the mounting plate is re-positioned there is a chance of the cylinder assembly moving out of position, and each time the lock case assembly is placed onto or taken off the mounting plate there is a risk of the mounting plate or cylinder assembly being knocked out of position.
Compounding the above problems is the fact that the tail bar is normally loosely attached to the cylinder assembly. This allows the position of the tail bar to vary slightly so as to soak up tolerance stacks which could otherwise prevent it from being aligned with the lock case assembly and rotating freely. However, it also means that it is sometimes necessary to jiggle the tail bar to align it with the aperture in the lock case assembly as the lock case assembly is being placed onto the mounting plate. Jiggling the tail bar either requires a tool to be inserted into the gap between the lock case assembly and the mounting plate, or requires the cylinder assembly to be loosened so that the entire cylinder assembly can be jiggled. In either case, there is a risk of a component moving out of position.
Still further, with the lock case assembly having the bolt, which bears the force of any attempt to force the door open without unlocking it, the lock case assembly should be robustly attached to the door. The mounting plate, by which the lock case assembly is attached to the door, therefore needs to be relatively strong. It must therefore be relatively thick (and thus use a lot of material) and/or made of high strength material (which tends to be expensive). The tooling costs associated with making such a mounting plate can also be higher.
The present invention seeks to mitigate or obviate at least one of the above disadvantages, and/or to provide an improved or alternative night latch assembly, mounting plate, method of fitting a night latch assembly to a door, or door.

Summary of the Invention

According to a first aspect of the present invention there is provided a night latch assembly comprising a cylinder assembly, a lock case assembly and a mounting plate, wherein:

the cylinder assembly and the mounting plate have mutually co-operative attachment structures by which they are attachable to one another; and
the mounting plate has a rear face for engaging a face of a door, and a projection extending rearwards from the rear face.

The projection of the mounting plate can be inserted into a hole in a door during fitting, thereby acting as a positioning feature that reduces the difficulty associated with positioning components and/or holding them in position. For example, by drilling the hole in the correct position the mounting plate may be placed in, and held in, the correct position simply by inserting the projection into the hole, thereby reducing or eliminating the need for trial and error. The projection being received in the hole can also provide support to the mounting plate before it is attached to the cylinder assembly, thereby making it easier to attach it to the cylinder assembly from opposite faces of the door. The support offered by the projection can also provide support to the cylinder assembly when the cylinder assembly is attached thereto, thereby reducing the risk of that component moving out of position.
Instead or as well, the support that can be provide by the projection may be advantageously strong and/or stable, which may allow the mounting plate to be made from less material and/or weaker material (and thus made at reduced cost).
The projection may project from the rear face over a length of at least 1mm, for instance at least 2mm, at least 3mm or at least 4mm.
The mounting plate may have a plate thickness, and the projection may extend rearward from the rear face over a length that is at least equal to the plate thickness (for instance at least twice, at least three times or at least four times the plate thickness).
The rear face of the mounting plate may be generally flat, i/e/ substantially devoid of other projections extending therefrom. Where the rear face is generally flat it may be generally planar, or gently convex and/or concave.
For the avoidance of doubt the term "cylinder assembly" is used to refer to the fact that this component generally contains a lock cylinder. It is not intended to imply that the cylinder assembly itself, or any part thereof, is necessarily cylindrical in shape.
The cylinder assembly may comprise a lock cylinder. The lock case assembly may comprise a rotatable handle and/or a bolt for receipt within a keep. Where the cylinder assembly has a lock cylinder and the lock case assembly comprises a rotatable handle, the night latch assembly may comprise a tail bar configured to extend between the cylinder assembly and lock case assembly and rotationally couple the lock cylinder and the handle.
The mounting plate may be made from metal, for instance brass, zinc or steel. The mounting plate may be a stamped or forged component.
The projection may be generally circular in cross section.
Such a projection may fit snugly into a hole in the door which is also circular (this generally being the easiest shape of hole to form in a door). The projection may therefore be advantageously well supported by the hole. Instead or as well, the projection being circular in cross section may allow the it to be easily rotated in a hole in a door, such that the mounting plate can easily be rotated to the correct orientation with its projection in the hole.
As an alternative, the projection may have any other suitable cross-sectional shape, for instance rectangular (e.g. square), hexagonal or star-shaped.
The projection may extend over a length, and have a generally constant cross-sectional size along its length.
For example where the projection is circular in cross section the projection may be generally cylindrical rather than conical or frustoconical). As another example where the projection is square in cross section the projection may be cuboidal rather than pyramidal.
The projection having a generally constant cross-sectional size can allow it to fit particularly well into a hole of constant cross-sectional size (this generally being the easiest shape of hole to form in a door), allowing the projection to be advantageously well supported.
As an alternative, the projection may taper along its length.
The projection may have an aperture configured to receive a tail bar therethrough.
With a hole being provided in the door to accommodate the projection, the projection having such an aperture can allow the tail bar to pass through the same hole rather than needing a separate one. Further, with the aperture of the projection allowing it to be positioned at the same general location as the tail bar, which is generally roughly central within a night latch, the projection can also be roughly central. The projection (and thus the hole) being roughly central within the night latch assembly may allow it to provide better support.
The aperture may be positioned towards a bottom of the projection relative to a longitudinal axis of the projection. In conventional cylinder assemblies the tail bar is normally positioned towards the bottom. With the aperture so positioned in the projection, the projection may be relatively well centred relative to the cylinder assembly as a whole, which may allow a narrower hole in the door to receive both the projection and part of the cylinder assembly. Put another way, it may be relatively easy for the hole in the door that is conventionally drilled to accommodate the cylinder assembly, and the hole needed for the projection, to be the same hole.
The projection may be hollow, defining a cavity therein.
This can allow the mounting plate to be lighter and/or easier to manufacture by stamping or the like. Instead or as well, the cavity may accommodate one or more other components, providing a more compact arrangement.
As an alternative, the projection may be solid.
Optionally:

the mounting plate has a base which provides the rear face and which has a base thickness;
the projection has a circumferential wall surrounding the cavity; and
the circumferential wall has a wall thickness that is substantially the same as the base thickness.

This may make the mounting plate particularly straightforward to manufacture using stamping or the like.
The lock case assembly may have a protrusion positioned for receipt within the cavity of the mounting plate.
The protrusion being received within the cavity may provide an advantageously compact arrangement.
The protrusion of the lock case assembly may include a tail bar, or an aperture for receipt of a tail bar.
With the protrusion reaching towards tail bar if it has an aperture, or reaching the tail bar toward the cylinder assembly if the protrusion includes the tail bar, the (unsupported) length of the tail bar can be reduced, making it more stable and able to be aligned with an aperture with less jiggling. Instead or as well, the tail bar having a shorter unsupported length can make it stronger and/or more rigid.
The mounting plate may comprise one or more screw holes which are provided outside of the projection.
By inserting a screw or other fastener though such a screw hole, the mounting plate can be prevented from rotating about the projection and thereby secured in the required angular orientation (for instance during tightening of a different screw).
For the avoidance of doubt the term "screw hole" is not intended to imply that it must receive a screw specifically. Rather a screw hole may be considered to be any hole which can accommodate a fastener such as a screw, bolt, threaded rod or rivet.
The cylinder assembly may have a corresponding one or more screw holes which are alignable with said screw holes, or may have a corresponding one or more fasteners configured for receipt in said screw holes, the screw holes or fasteners of the cylinder assembly and the screw holes of the mounting plate thereby forming at least part of the attachment structures.
The screw holes may thereby serve both to prevent the mounting plate from rotating (as above) and to attach the mounting plate to the cylinder assembly. This may reduce the number of parts needed and/or the time taken to fit the night latch assembly to a door.
As an alternative, said screw hole(s) may be positioned for screwing of the mounting plate to the door.
The attachment structure of the mounting plate may include one or more attachment features provided on the projection.
This can allow a hole in the door, provided to accommodate the projection, to also be used by the attachment features (for instance accommodating fasteners running between the mounting plate and the cylinder assembly). This can reduce the need for extra holes being provided for use with the attachment features, thereby reducing the time taken to fit the night latch assembly.
Said one or more attachment features may be screw holes provided through the projection.
This may allow the mounting plate to be particularly compact and/or manufactured particularly easily.
As one alternative, the attachment features may be threaded rods extending from the aperture for receipt by the cylinder assembly.
According to a second aspect of the present invention there is provided a mounting plate for a night latch assembly according to the first aspect of the invention.
Such a mounting plate may provide one or more of the advantages discussed above.
According to a third aspect of the present invention there is provided a method of fitting a night latch assembly to a door, the night latch assembly having a cylinder assembly, a lock case assembly and a mounting plate, the method comprising:

providing a hole in the door;
presenting the mounting plate and cylinder assembly to opposite faces of the door;
with a projection of the mounting plate received in the hole, attaching the cylinder assembly and mounting plate to one another with the door clasped therebetween; and
attaching the lock case assembly to the door in a position in which it overlies the mounting plate and engages the cylinder assembly.

As discussed above, the projection being received in the hole can act as a positioning feature that reduces the difficulty associated with positioning components and/or holding them in position.
The hole in the door may be circular in cross sectional shape. Alternatively it may have any other suitable shape such as rectangular (e.g. square), hexagonal or octagonal in cross section.
When so attached, the lock case assembly may partially overlie the mounting plate, or may substantially entirely or entirely overlie the mounting plate.
The projection may be snugly received in the hole, that is to say that it may be received within the hole with minimal gap therewith. Indeed, the projection may be received within the hole with an interference fit.
The hole may be a blind hole or a through-hole.
The hole may be between 30 and 35mm in diameter inclusive, for instance around 32mm. This may allow the cylinder assembly to be of conventional size and layout.
The projection of the mounting plate may be inserted into the hole before the cylinder assembly and mounting plate are attached together, the attachment between the cylinder assembly and mounting plate then being tightened so as to clasp the door therebetween.
The projection may therefore be able to support the mounting plate before and/or during attachment of the mounting plate to the cylinder assembly, reducing the above difficulties with that part of the process.
As an alternative, the mounting plate and cylinder assembly may be attached to one another loosely before the projection is received in the hole. The attachment therebetween may then be tightened so as to first insert the projection into the hole and then clasp the door between the cylinder assembly and the mounting plate.
With the projection of the mounting plate received in the hole, at least the mounting plate may be rotated about the projection to a required orientation before the door is clasped between the cylinder assembly and the mounting plate.
It may be easier for a fitter to insert the projection into the hole and then rotate the mounting plate into the required orientation, rather than first positioning the mounting plate in the required orientation and then inserting the projection into the hole while trying not to rotate it out of the required orientation.
It may be solely the mounting plate which is rotated about the projection. As an alternative, it may be that the mounting plate and cylinder assembly are rotated together about the projection.
The method may further comprise drilling one or more additional holes in the door, and for the or each additional hole inserting a corresponding fastener through a corresponding screw hole in the mounting plate and into the additional hole.
Inserting at least one fastener through a screw hole in the mounting plate and into at least one additional hole in the door may help to hold the mounting plate in position (for instance preventing it from rotating out of its required orientation and/or stopping its projection from falling out of the hole).
The or each fastener may run from a head end, through the screw hole in the mounting plate and into (or through) the additional hole in the door. As an alternative, the or each fastener may run from a head end (which may be part of the cylinder assembly), through the additional hole and into (or through) the screw hole.
Said screw hole(s) in the mounting plate may be provided outside of the projection.
The or each fastener may run through its additional hole and into a corresponding hole in the cylinder assembly
Said fastener(s) may therefore form part of the mechanism by which mounting plate and cylinder assembly are attached together, thereby reducing the need for extra components to be provided and/or extra operations to be performed.
The night latch assembly may be a night latch assembly according to the first aspect of the invention.
Such a night latch assembly may provide one or more of the advantages discussed above in respect of the first aspect of the invention.
According to a fourth aspect of the present invention there is provided a door fitted with a night latch assembly according to the first aspect of the invention and/or a night latch assembly fitted using a method according to the third aspect of the invention.
Such a door may be advantageously quick or low cost to produce and/or assemble, and/or may be advantageously strong, for one or more of the reasons given above.
According to a fifth aspect of the present invention there is provided night latch assembly comprising a cylinder assembly, a lock case assembly and a mounting plate, wherein:

the cylinder assembly and mounting plate have mutually co-operative attachment structures by which they are attachable to one another;
the lock case assembly and mounting plate do not have mutually co-operative attachment structures by which they are attachable to one another; and
the lock case assembly has an attachment structure configured for attachment of the lock case assembly to a door.

Accordingly, the lock case assembly and mounting plate are not configured for direct attachment to one another. Rather the cylinder assembly and mounting plate may mutually secure one another on the door, and the lock case may be secured to the door separately. The lack of direct attachment between the lock case assembly and the mounting plate can reduce the above need to secure the mounting plate in a position at which the lock case assembly, when attached thereto, is positioned correctly. This, in turn, may reduce the amount of "trial and error" fitting that is required, and/or reduce the number of components which must be simultaneously held in the correct position.
Instead or as well, such a lack of direct attachment between the lock case assembly and the mounting plate can reduce the risk of tolerance stacking bringing components out of alignment, and/or can allow the same mounting plate to be used with a wider variety of different lock case assemblies. Such reduced tolerance stacking and/or increased interchangeability can reduce the overall tooling costs associated with a range of different night latch products.
Alternatively or in addition, with the lock case assembly not being mounted to the door via the mounting plate, loads experienced by the lock case assembly (for instance due to someone trying to force the door open) are not necessarily transferred to the mounting plate. Accordingly, there may be less need for the mounting plate to be particularly strong, meaning that it may be made smaller, lighter and/or at reduced cost.
The mounting plate may have a rear face for engaging a face of the door, and a generally flat front face with substantially no projections extending therefrom.
The mounting plate having such a front face may reduce the extent to which the mounting plate and lock case assembly must occupy particular positions relative to one another when mounted on a door. This may provide or magnify one or more of the above advantages.
As an alternative, the front face may have one or more projections arranged for a purpose other than attachment of the mounting plate to the lock case assembly.
The lock case assembly may have a rear face for mounting to a face of the door, the rear face being shaped to substantially entirely overlie the mounting plate.
In other words, the rear face may be large enough, and of the correct shape, to substantially cover the mounting plate when the lock case assembly is attached to the door.
The mounting plate may have an aperture for receipt of a tail bar therethrough, and the lock case assembly may have a tail bar or an aperture. The rear face may be shaped to substantially entirely overlie the mounting plate when said aperture of the mounting plate is aligned with the aperture or tail bar of the lock case assembly.
The rear face of the lock case assembly may have a recess into which at least part of the mounting plate is receivable.
This may allow the lock case assembly to shield the mounting plate (which may not be particularly aesthetic) from view. Instead or as well it may reduce the size of a gap between the rear face and the face of the door, reducing the possibility of dust ingress (or leakage of oil or the like) through the gap.
Said at least part of the mounting plate may be movable when received within the recess.
This may afford the lock case assembly improved freedom of movement relative to the mounting plate, reducing the extent to which the position of one determines the position of the other.
The attachment structure of the lock case assembly may have one or more screw holes positioned for attachment of the lock case assembly to the door using fasteners.
Such screw holes may provide an advantageously simple mechanism by which the lock case can be attached to the door.
Such screw holes may be positioned for non-alignment with the mounting point by being positioned adjacent to one or more edges of the lock case so as to be positioned outside the footprint of the mounting plate. As an alternative, the mounting point may have apertures for alignment with the screw holes of the lock case, said apertures being sufficiently large to avoid direct interaction between the mounting plate and fasteners inserted through the screw holes.
The or each screw hole may be positioned beneath a handle of the lock case assembly, the or each screw hole being selectively accessible by rotation of the handle.
The handle may therefore be positionable to shield the screw holes (which may be considered unsightly and/or may be subjected to tampering) from view.
The attachment structure of the mounting plate may comprise one or more screw holes configured for alignment with a corresponding one or more screw holes or fasteners provided by the attachment structure of the cylinder assembly, and the mounting plate may comprise no other screw holes.
Each of said fasteners may be a threaded rod, screw, bolt, rivet or the like.
As an alternative, the mounting plate may have one or more further screw holes for attachment of another component (other than the lock case assembly) thereto.
The mounting plate may have a rear face for engaging a surface of the door, and a projection extending rearward from the rear face.
This may provide one or more of the advantages discussed above in respect of the first aspect of the invention.
According to a sixth aspect of the present invention there is provided a night latch assembly comprising a cylinder assembly, a lock case assembly and a mounting plate, wherein:

the cylinder assembly and mounting plate have mutually co-operative attachment structures by which they are attachable to one another;
the lock case assembly has an attachment structure configured for attachment of the lock case assembly to a door; and
the mounting plate has a generally flat front face with substantially no projections extending therefrom.

This arrangement may provide one or more corresponding advantages to those discussed in respect of the fifth aspect of the invention.
According to a seventh aspect of the present invention there is provided a mounting plate for a night latch assembly according to the fifth or sixth aspect of the invention.
Such a mounting plate may provide one or more of the advantages discussed above
According to an eighth aspect of the present invention there is provided a method of fitting a night latch assembly to a door, the night latch assembly having a cylinder assembly, a lock case assembly and a mounting plate, method comprising:

securing the cylinder assembly on a first face of a door and securing the mounting plate on a second face of the door which is opposite to the first face; then
securing the lock case assembly to the second face of the door such that the lock case assembly overlies the mounting plate without the lock case assembly and mounting plate being secured together directly, the lock case assembly and mounting plate being secured to one another by virtue of each being secured to the door.

The lock case assembly being secured to the door without being secured directly to the mounting plate can reduce the above described need to secure the mounting plate in a position at which the lock case assembly, when attached thereto, is positioned correctly. This, in turn, may reduce the amount of "trial and error" fitting that is required, and/or reduce the number of components which must be simultaneously held in the correct position during fitting.
Instead or as well, such a lack of direct attachment between the lock case assembly and the mounting plate can reduce the risk of tolerance stacking bringing components out of alignment and preventing fitting from being completed.
Alternatively or in addition, with the lock case assembly not being mounted to the door via the mounting plate, loads experienced by the lock case assembly (for instance due to someone trying to force the door open) are not necessarily transferred to the mounting plate. Accordingly, there may be less chance of failure of mounting plate during use after fitting.
For the avoidance of doubt, the lock case assembly and the mounting plate not being secured together directly is not intended to imply that they may not touch one another.
The step of securing the lock case assembly to the second face of the door may include moving the lock case assembly relative to the mounting plate, with the cylinder assembly and mounting plate secured to their respective faces of the door, so as to align the lock case assembly with the cylinder assembly.
Aligning the lock case assembly with the cylinder assembly after the cylinder assembly has been secured may allow a fitter to first concentrate on positioning the cylinder assembly correctly and then concentrate on positioning the lock case assembly correctly, rather than needing to position both at the same time.
Aligning the lock case assembly with the cylinder assembly may include aligning a tail bar projecting from one of those components with an aperture provided in the other of said components.
The lock case assembly may be secured to the door using threaded fasteners which threadedly engage the door.
This may be an advantageously simple and/or robust method for securing the lock case assembly.
The threaded fasteners may threadedly engage the wood of a wood door, or respective nut inserts in an aluminium or composite door, for example.
Instead or as well, the lock case assembly may be secured to the door by virtue of being secured to the cylinder assembly through the door.
The step of securing the cylinder assembly and mounting plate on their respective faces of the door may comprise attaching the cylinder assembly and mounting plate to one another through the door with the door clasped therebetween.
This may be an advantageously rugged and/or quick way of securing the cylinder assembly and mounting plate.
Instead or as well, the mounting plate and/or the cylinder assembly may be attached directly said face of the door.
The step of securing the lock case assembly to the second face of the door may comprise placing a recess in a rear face of the lock case assembly onto the second face of the door over at least part of the mounting plate, and moving the lock case assembly over the second face of the door with said at least part of the mounting plate moving within the recess.
The step of securing the cylinder assembly to the first face of the door and securing the mounting plate on the second face may comprise:

providing a hole through the door; and
inserting a projection of the mounting plate into the hole.

This may provide one or more of the advantages discussed above in respect of the third aspect of the invention.
The night latch assembly may be a night latch assembly according to the fifth or sixth aspect of the invention.
Such a night latch assembly may provide one or more of the advantages discussed above in respect of the fifth aspect of the invention.
According to a ninth aspect of the present invention there is provided a door fitted with a night latch assembly according to the fifth or sixth aspect of the invention and/or a night latch assembly fitted using a method according to the eighth aspect of the invention.
Such a door may be advantageously quick or low cost to produce and/or assemble, and/or may be advantageously strong, for one or more of the reasons given above.
According to a further aspect of the invention, there is provided a kit of parts for forming a night latch assembly, the kit of parts comprising a cylinder assembly, a lock case assembly, and a mounting plate, wherein the cylinder assembly and mounting plate have mutually co-operative attachment structures by which they are attachable to one another; the lock case assembly and mounting plate do not have mutually co-operative attachment structures by which they are attachable to one another; and the lock case assembly has an attachment structure configured for attachment of the lock case assembly to a door.
It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. Additionally, a method of the invention may incorporate any of the features described with reference to an apparatus of the invention and vice versa.

Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

Figure 1 is an exploded view of part of a door according to an embodiment of the invention viewed from inside a building;
Figure 2 is an exploded view of the part of the door of Figure 1, viewed from outside the building;
Figure 3 is a front view of a mounting plate of a night latch assembly of the door of Figures 1 and 2; and
Figure 4 is a front view of a lock case assembly of the night latch assembly, along with a keep.

Detailed Description

Figures 1 and 2 show an exploded view of part of a door 2 according to an embodiment of the invention. The door 2 has a leaf 4 and a night latch assembly 6 which is secured to the leaf 4 via screws 8, 10, 12. The door 2 of this embodiment is a wooden door to a building such as a house. It has a first face 14 which faces outside the building, and a second face 16 which faces inside the building. In Figures 1 and 2 the door 2 is shown along with part of a frame 18 which has supports a keep 20. The frame 18 and keep 20 are not material to the present invention, therefore will not be described in detail.
The night latch assembly 6 comprises a cylinder assembly 22, a mounting plate 24 and a lock case assembly 26. Figure 3 shows the mounting plate 24 in isolation and Figure 4 shows the lock case assembly 26 in isolation. Referring now to Figures 1 to 4, the cylinder assembly 22 has a housing 28 which defines a handle lip 30 descending from its front, and two pairs of threaded holes 32, 34 at its rear. Inside the housing 28 of the cylinder assembly 22 is a lock cylinder 36, and extending rearwards from the rear of the housing 28 is a tail bar 38 which is rotationally coupled to the lock cylinder 36.
The mounting plate 24 has a base 40 which defines a generally flat and planar rear face 42 for engaging the second face 16 of the door 2, with a projection 44 extending rearward therefrom. The base 40 also has a front face 46 opposite to the rear face 42. The front face is also flat and planar, like the rear face 42, but unlike the rear face 42 the front face is devoid of any projections.
The projection 44 extends rearward over a length which in this embodiment is around five times the thickness of the base 40. The projection 44 is cylindrical in shape. The projection 44 is hollow, having a circumferential wall 48 surrounding a cavity 50. In the present embodiment the thickness of the base 40, and the thickness of the circumferential wall 48 are substantially the same at around 2mm thick.
The projection 44 also has a circular end wall 52 which has an aperture 54 and a pair of screw holes 56 therein. The portions of the circumferential wall 48 next to the screw holes 56 are scalloped slightly, making those small portions of the wall slightly thinner than the 2mm thickness of the wall in general.
As well as the two screw holes 56 provided on the projection 44, the mounting plate 24 has two screw holes 58 provided outside of the projection 44. These screw holes 58 are provided in the base 40, above and below the projection 44 (when the mounting plate 24 is in the correct orientation to be secured to the door). Each screw hole 58 has a slightly raised edge around it on the rear face 42 of the base 40, meaning that while the rear face 42 is generally flat it is not perfectly flat.
The four screw holes 56, 58 of the mounting plate 24 are each attachment features which together form an attachment structure by which the mounting plate 24 is attachable to the cylinder assembly 22. Equally, the threaded holes 32, 34 of the cylinder assembly 22 are each attachment features which together form an attachment structure by which the cylinder assembly 22 is attachable to the mounting plate 24. The screw holes 56 on the projection 44 of the mounting plate 24 are configured for alignment with the threaded holes 32 of the cylinder assembly 22, and the screw holes 58 in the base 40 of the mounting plate 24 are configured for alignment with the threaded holes 34 of the cylinder assembly 22. When the cylinder assembly 22 and the mounting plate 24 are correctly positioned on their respective sides of the door, screws 8 can run from respective head ends, through the holes 56, through the leaf 4 of the door and into the threaded holes 32. Equally, screws 10 can run from respective head ends, through the holes 58, through the leaf 4 and into the threaded holes 34. The screws 8, 10 can threadedly engage with their respective threaded holes 32, 34 in the cylinder assembly 22, thereby attaching the cylinder assembly 22 and mounting plate 24 to one another as discussed later.
The lock case assembly 26 has a housing 60 with a handle 62 mounted on its front, and a rear face 64 configured for mounting to the second face 16 of the door 2. The handle 62 is rotatable to retract a bolt 65 which is receivable in the keep 20. The rear face 64 defines a shallow recess 66 into which a protrusion 68 extends. The protrusion 68 has an aperture 70 configured to receive the end of the tail bar 38, and is rotationally coupled to the handle 62.
The lock case assembly 26 also has a pair of screw holes 72 which form an attachment structure configured for attachment of the lock case assembly 26 to the second face 16 of the door 2 using screws 12. Each screw hole 72 is positioned towards the edge of the lock case assembly 26 so that when the night latch assembly 6 is mounted to the leaf 4 of the door, the screws 12 do not interact with the mounting plate 24.
Each screw hole 72 is also positioned beneath the handle 62, and is selectively accessible by rotation of the handle 62. With the handle 62 in the position shown in Figures 1 and 2 neither screw hole 72 is accessible. As shown in Figure 4, if the handle is rotated clockwise (from the perspective of Figure 4) then one of the screw holes 72 becomes visible. Equally, if the handle is rotated anticlockwise (from the perspective of Figure 4) then the other screw hole 72 becomes visible.
It is noteworthy that while the cylinder assembly 22 and mounting plate 24 have mutually co-operative attachment structures by which they are attachable to one another, the lock case assembly 26 and mounting plate 24 do not have mutually co-operative attachment structures by which they are attachable to one another. Rather, all the attachment features 56, 58 of the mounting plate 24 form the attachment structure by which it is attached to the cylinder assembly 22, and the attachment structure of the lock case assembly 26 formed by the screw holes 72 is configured for attachment of the lock case assembly 26 to the door 2. Thus, the lock case assembly 26 and mounting plate 24 are not configured to be connected to one another directly.
With the night latch assembly 6 fitted to the door 2 or positioned accordingly, the rear face 64 entirely overlies the mounting plate 24, the base 40 of the mounting plate 24 is received in the recess 66 and the protrusion 68 projects into the cavity 50. In the absence of the screws 12, the lock case assembly 26 is movable over the face 16 of the door 2, with the base 40 of the mounting plate 24 moving within the recess 66 and the protrusion 68 moving within the cavity 50.
A method of fitting the night latch assembly 6 to the door 2 will now be described with continued reference to Figures 1 to 4. A first step of the method is to drill a main hole 74 and two additional holes 76 in the leaf 4 or the door 2. In this case each hole 74, 75 is a through-hole, passing through both the first and second faces 14, 16. The main hole 74 is around 32mm in diameter, being sized to accommodate the projection 44 and the rear parts of the cylinder assembly 22 which provide the screw holes 32, while the additional holes are considerably smaller (around 6mm), each being sized to accommodate one a part of the cylinder assembly 22 which provides one of the screw holes 34.
After drilling of the holes 74, 76 in the door, the cylinder assembly 22 is presented to the first face 14 of the door and the mounting plate 24 is presented to the second face 16 of the door. The projection 44 of the mounting plate 24 is then inserted into the main hole 74, which snugly receives the projection. The mounting plate 24 is then rotated about the projection 44 until it reaches the required orientation, with the screw holes 58 aligned with the additional holes 76 and the aperture 54 towards the bottom of the projection 44. With the projection 44 snugly received in the main hole 74, the door 2 supports the mounting plate 24 without assistance from the fitter.
The cylinder assembly 22 is then applied to the first face 14 of the door 2. The tail bar 38 and the rear parts of the housing 28 that provide the threaded holes 32 are inserted into the main hole 74. The screw holes 32 terminate within the main hole 74 whereas the tail bar 38 extends through the aperture 54 in the mounting plate, all the way through the hole 74, and projects past the second face 16. At the same time, the parts of the housing 28 which provide the threaded holes 34 are inserted into respective additional holes 76, within which they terminate.
With the cylinder assembly 22 and mounting plate 24 so positioned, they are held in place by the door 2 and protected from shifting out of position by knocks or the like. The cylinder assembly 22 and mounting plate 24 are then attached to one another using screws 8, 10. Screws 8 are inserted through screw holes 56 of the mounting plate 24, through the main hole 74 and into respective screw holes 32 of the cylinder assembly 22. Screws 10 are inserted through screw holes 58 of the mounting plate 24, through respective additional holes 76 and into respective screw holes 34 of the cylinder assembly 22. The screws 8, 10 engage their respective threaded screw holes 32, 34, attaching the cylinder assembly 22 and mounting plate 24 together. As the screws 8, 10 are tightened, they draw the cylinder assembly 22 and mounting plate 24 towards one another until they are secured on their respective faces 14, 16 of the door 2 and clasp the door 2 therebetween.
After the cylinder assembly 22 and mounting plate 24 are secured on their respective faces 14, 16 of the door, due to being attached together by the attachment structures provided by their respective screw holes 32, 34, 56, 58, the lock case assembly 26 is attached to the door 2. The lock case assembly 26 is presented to the the door 2 with its rear face 64 facing the second face 16 of the door 2. The aperture 70 in the protrusion 68 is aligned with, and then slid onto, the tail bar 38. This brings the rear face 64 of the housing 60 of the lock case assembly 26 into abutment with the second face 16 of the door 2, with the rear face 64 of the lock case assembly 26 entirely overlying the mounting plate 24 and shielding it from view. Placing the lock case assembly 26 against the second face 16 of the door also inserts the base 40 of the mounting plate 24 into the recess 66 and inserts the protrusion 68 into the cavity 50.
With the lock case assembly 26 so positioned it is moved over the face 16 of the door 2, with the base 40 of the mounting plate 24 moving within the recess 66 and the protrusion 68 moving within the cavity, so as to find the location where the tail bar 38 experiences the least resistance to rotation. In this position the tail bar 38 rotationally couples the lock cylinder 36 of the cylinder assembly 22 and the handle 62 of the lock case assembly 26, so that rotation of either one retracts the bolt 65, with least friction and wear.
The lock case assembly 26 is then attached to the door 2 in this position. Screws 12 are inserted through the screw holes 72 (which are accessed by rotating the handle 62 as described above), where they threadedly engage with the wood of the door leaf 4 and secure the lock case assembly 26 in place. With the lock case 26 so attached, it is secured to the mounting plate 24 by virtue of both components being secured to the door 2. They are not, however, directly secured to one another. In embodiments where a more robust attachment is needed, extra screw holes can be provided, for instance through a strike plate of the lock case assembly 26, with screws through those screw holes also attaching the lock case assembly 26 to the door rather than securing it directly to the mounting plate 24.
Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims

A night latch assembly (6) comprising a cylinder assembly (22), a lock case assembly (26) and a mounting plate (24), wherein:
the cylinder assembly (22) and mounting plate (24) have mutually co-operative attachment structures (32, 34, 56, 58) by which they are attachable to one another;

the lock case assembly (26) and mounting plate (24) do not have mutually co-operative attachment structures by which they are attachable to one another; and

the lock case assembly (26) has an attachment structure (72) configured for attachment of the lock case assembly (26) to a door (2).
A night latch assembly according to claim 1 wherein the mounting plate has a rear face for engaging a face of the door, and a generally flat front face with substantially no projections extending therefrom.
A night latch assembly according to claim 1 or claim 2 wherein the lock case assembly has a rear face for mounting to a face of the door, the rear face being shaped to substantially entirely overlie the mounting plate.
A night latch assembly according to claim 3 wherein the rear face of the lock case assembly has a recess into which at least part of the mounting plate is receivable.
A night latch assembly according to claim 4 wherein said at least part of the mounting plate is movable when received within the recess.
A night latch assembly according to any preceding claim wherein the attachment structure of the lock case assembly has one or more screw holes positioned for attachment of the lock case assembly to the door using fasteners.
A night latch assembly according to claim 6 wherein the or each screw hole is positioned beneath a handle of the lock case assembly, the or each screw hole being selectively accessible by rotation of the handle.
A night latch assembly according to any preceding claim wherein the attachment structure of the mounting plate comprises one or more screw holes configured for alignment with a corresponding one or more screw holes or fasteners provided by the attachment structure of the cylinder assembly, the mounting plate comprising no other screw holes.
A night latch assembly according to any preceding claim wherein the mounting plate has a rear face for engaging a surface of the door, and a projection extending rearward from the rear face.
A mounting plate for a night latch assembly according to any preceding claim.
A method of fitting a night latch assembly (6) to a door (2), the night latch assembly (6) having a cylinder assembly (22), a lock case assembly (26) and a mounting plate (24), method comprising:
securing the cylinder assembly (22) on a first face of a door (2) and securing the mounting plate (24) on a second face of the door (2) which is opposite to the first face; then

securing the lock case assembly (26) to the second face of the door such that the lock case assembly (26) overlies the mounting plate (24) without the lock case assembly (26) and mounting plate (24) being secured together directly, the lock case assembly (26) and mounting plate (24) being secured to one another by virtue of each being secured to the door (2).
A method according to claim 11 wherein the step of securing the lock case assembly to the second face of the door includes moving the lock case assembly relative to the mounting plate, with the cylinder assembly and mounting plate secured to their respective faces of the door, so as to align the lock case assembly with the cylinder assembly.
A method according to claim 11 or 12, wherein the step of securing the lock case assembly to the second face of the door comprises placing a recess in a rear face of the lock case assembly onto the second face of the door over at least part of the mounting plate, and moving the lock case assembly over the second face of the door with said at least part of the mounting plate moving within the recess.
A door fitted with a night latch assembly according to any one of claims 1 to 9 and/or a night latch assembly fitted using a method according to any one of claims 11 to 13.
A kit of parts for forming a night latch assembly, the kit of parts comprising a cylinder assembly, a lock case assembly, and a mounting plate, wherein:
the cylinder assembly and mounting plate have mutually co-operative attachment structures by which they are attachable to one another;

the lock case assembly and mounting plate do not have mutually co-operative attachment structures by which they are attachable to one another; and

the lock case assembly has an attachment structure configured for attachment of the lock case assembly to a door, the kit of parts thereby being configured to form a night latch assembly according to any one of claims 1 to 9.