GB2278877A

GB2278877A - Backplate for a door handle

Info

Publication number: GB2278877A
Application number: GB9411415A
Authority: GB
Inventors: Calvin N Collins
Original assignee: N T BRASSART Ltd
Current assignee: N T BRASSART Ltd
Priority date: 1993-06-09
Filing date: 1994-06-08
Publication date: 1994-12-14
Also published as: GB9411415D0; GB9311923D0

Abstract

A backplate assembly has its means of fixing 8 to a door or window concealed from view, or substantially so. A base plate 2 of the assembly is secured by fixing screws 8 to the door or window, and a cover which extends around and conceals the base plate 2 is releasably retained to the base plate by retention means at a peripheral flange 16 co-operating with an anchorage at the base plate. In one form the retention means comprises a grub screw 19 which tightens against an inclined lug 9 of the base plate; in another form resilient lips of the base plate spring into co-operation with undercuts of the peripheral flange. A drive unit 4 for a handle 5 may be provided and retained by flanges 13 in the base plate. <IMAGE>

Description

BACKPLATE FOR A DOOR HANDLE This invention relates to a backplate assembly typically for a door handle. The handle may be a lever or knob, and, whilst primarily intended for use with doors for operating a latch mechanism, it may also be used with French and casement windows.

Conventionally backplates are fixed by screws engaged in holes opening to the fronts of the backplates so that the heads of the screws are exposed at the fronts of the secured backplates. The exposed screw heads can detract from the appearance of the fixed backplates. Shell-like covers have been proposed to fit over backplates to conceal the screw heads when the backplates are fixed in position for use. These covers have also concealed the backplates. They have not always been satisfactory. For example they have tended to be relatively flimsy, they have not fitted properly on the backplates, or they have been of poor quality or design.

The present invention provides another solution.

According to a first aspect of the present invention a backplate assembly is provided comprising a base plate which is adapted to be secured by fixing screws to a door or window, and a cover which extends over the base plate, has a peripheral flange which extends around the base plate and which cover is releasably retained to the base plate by retention means at the peripheral flange co-operating with an anchorage at the base plate.

The cover may be generally similar in form to a conventional backplate but without the holes in the front for fixing screws. It may take other forms, if desired. It can be of a robust structure, and the absence of fixing screw holes in the front provides appreciable freedom in the designing of its appearance.

The anchorage at the base plate may be a retaining shoulder, lug or other location behind or against which the retention means abuts to secure the cover to the base plate. Another possibility is for the retention means to engage in a retaining aperture or recess at the base plate.

In addition to the retention means, the base plate and cover may have co-operating parts or formations which interengage to assist in retention of the cover on the base plate. Such parts or formations may be arranged to engage as the cover is being applied to the base plate, and to provide a means of facilitating correct location of the cover on the base plate for the retention means to be engaged with the anchorage.

In a preferred embodiment the retention means comprises screw means. Preferably the screw means comprises at least one grub screw engaged in a hole in the peripheral flange and which when tightened does not project, or not significantly, from or is recessed within the flange, so as to be substantially concealed from view.

In an alternative embodiment, the retention means may comprise a projecting flange which is retained by the anchorage when the flange is mounted on the base plate. The anchorage preferably comprises a resiliently deflectable lug projecting from the base plate which is deflected by the flange to allow the flange to pass behind it and then retains the flange between itself and the door or window on which the base plate is mounted.

Very commonly, the cover may be adapted to have a handle located on it (although it may also be used as a simple push plate.). In such backplate assemblies further assistance in the retention of the cover on the base plate may be provided by the handle located on the backplate for use. A handle fitted on a latch-operating spindle may, for example, have a journal which locates in a bearing hole in the cover, in the usual way of a handle in a conventional backplate, and a shoulder at the root of the journal which overlies the margin of the bearing hole at the front of the cover.

Spring loading may be provided within the backplate assembly for urging a rotatable handle to an inoperative position. A member rotatable with the handle may limit the extent of the rotation of the handle by having a projection which moves between movement-limiting stops fixed relative to the base plate. The member and spring means may be incorporated in a self-contained drive unit which is drivingly engaged with the handle, or a latch-operating spindle, to spring-urge the handle to an inoperative position.

Coventionally, the base plate includes a recess between itself and the door or window to which it is attached, a drive unit for returning the handle to its inoperative position being located in the recess and secured there through its being sandwiched between the base plate and the door or window. This arrangement has the disadvantage that there must be at least two layers of metal, that is to say the base plate and the cover outwardly of the biasing means so increasing the minimum thickness of the backplate assembly. This is of particular disadvantage in the case of high-quality backplate assemblies in which the cover is made of cast metal and is necessarily of substantial thickness.

From a second of its aspects, the invention provides a backplate assembly comprising a base plate which is adapted to be secured by fixing screws to a door or window, and a cover plate which extends over the base plate and which is adapted to have a handle located on it, and a drive unit operative to urge the handle to an inoperable condition, the base plate having an aperture in which the drive unit is located and retaining formations adjacent to the aperture for retaining and inhibiting rotation of the drive unit relative to the base plate.

The provision of the aperture allows the drive unit to make contact with the door or window (it being preferably retained there through contact with the cover) so allowing the minimum achievable thickness of the backplate assembly to be reduced by the thickness of the base plate.

The retaining formations may comprise flanges upstanding from the base plate between which the drive unit is a tight fit. The flanges may be formed by deformation of portions of the base plate at the periphery of the aperture, which may conveniently be carried out when the aperture is formed, for example by punching or stamping.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a rear view of a cover of a backplate assembly being a first embodiment of the present invention; Figure 2 is a front view of a base plate of the backplate assembly of Figure 1; Figure 3 is a longitudinal section though the assembled backplate assembly of Figures 1 and 2; Figures 4a and 4b are front and side views of a base plate being an alternative to that shown in Figure 2 and being suitable for use in a backplate assembly embodying the second aspect of the invention; Figure 5 is an exploded view of a backplate assembly being an alternative embodiment of the first and second aspects of the invention; Figure 6a and 6b are front and side views of the base plate of the backplate assembly of Figure 5; ; and Figure 7 is a front view of a drive unit included in the backplate, shown with a closure part removed for clarity.

In the first embodiment the backplate assembly 1 comprises a base plate 2, a cover 3 and a drive unit 4. A lever handle 5 on the cover 3 is engaged with the drive unit 4 and a latch-operating spindle 6.

The base plate 2 is oblong and stamped and pressed out of sheet metal, conveniently mild steel. Near to its opposite ends there are plain holes 7 for fixing screws 8, Figure 3. Along one edge of the base plate 2 is a lug 9 which projects forwardly and slightly outwardly from the main body of the plate. Close to the opposite end of the base plate a forwardly-projecting conical protrusion 10 is pressed from the plate and is formed with a plain hole 11. In that half of the base plate 2 containing the conical protrusion 10 is a square aperture 12 at opposite sides of which, longitudinally of the base plate, are two forwardly projecting flanges 13. An oval opening 14 is formed in the other half of the base plate.

The cover 3 in this embodiment is a metal casting, for example of brass. It may take other forms, as desired. The cover has a front wall 15 and a continuous rearwardly projecting, peripheral flange 16, and is also oblong to fit over the base plate 2 with the peripheral flange 16 closely surrounding the edges of the base plate. There is a bearing hole 17 in the front wall, co-axial with the central axis of the square opening 12 in the base plate, to receive a journal portion 18 of the lever handle 5. Centrally at one end of the base plate, a grub screw 19 is engaged in a threaded hole in the peripheral flange 16, being positioned to bear on the lug 9 of the base plate when it is tightened. At the opposite end the cover has a short peg 20 on the back face of the front wall 15 to engage in the hole 11 of the conical protrusion 10 of the base plate.

With reference to Figure 7, the drive unit 4 comprises a relatively flat substantially square housing 21, with a closure part 22 secured by screws which tighten into screw threaded holes 23 in the housing. The housing 21 fits into the square aperture 12 of the base plate between the two flanges 13 which hold the unit in position, within the depth of the peripheral flange 16 of the cover. A rotary member 24, is journalled in the housing 21 and closure part 22.

An axial aperture 25 of oblong section extends through the rotary member 24. At one end the rotary member 24 has a radial projection 26 which extends into, and is angularly movable along, an arcuate recess 27 in the closure part 22. The ends of the recess 27 form stops for engagement by the radial projection 26 to limit the extent of the rotating movement of the rotary member.

A clock spring 28, located in an annular recess 29 in the housing 21 around the rotary member 24, has one end anchored to the rotary member 24 and the other end anchored to the housing to urge the rotary member 24 in one direction.

The journal portion 18 of the lever handle 5 is of complementary cross-sectional shape to and, projecting through the bearing hole 17 in the front wall 15 of the cover 3, engages in the axial aperture 25 of the rotary member 24. Thus the spring 27 of the drive unit 4 normally urges the handle 5 to rotate to an inoperative position. There is the usual square-section socket 30 in the journal 18 and stem 31 of handle to receive the latch-operating spindle 6. Where the journal 18 joins the stem 31 a shoulder 32 is formed around the journal.

To mount the backplate assembly 1 for use on a door, for example, the base plate 2 is first secured on a face of the door by the fixing screws 8, the square opening 12 being centred on the hole in the door for the latch-opening spindle 6 to extend through from the latch mechanism. The cover 3 is then fitted over the fixed base plate 2, the peg 20 first being engaged in the hole 11 of the conical protrusion 10 to locate the one end of the cover 3 before the other end of the cover 3 is swung, about the peg 20, into place on the base plate 2. Tightening the grub screw 19 to bear on the lug 9 fixes the cover 3 on the base plate 2.

Because of the slight outward inclination of the lug 9 the action of the grub screw 19 on the lug is to urge the cover 3 inwardly towards the door surface. When the handle 5 is subsequently fitted to the cover 3, and its journal portion 18 engaged in the axial aperture 25 of the rotary member 24 of the drive unit, the shoulder 32 lies close against the front wall of the cover 3 around the bearing hole 17 and provides further restraint to separation of the cover 3 from the base plate 2.

If the backplate assembly 1 is to be used with a mortice lock, the cover 3 will have a keyhole opposite the oval opening 14 in the base plate and the opening provides access to the keyhole in the door.

The base plate 2' shown in Figures 4a and 4b (in which features corresponding to those of the base plate of Figure 2 have been referenced with the numbers used in Figure 2 with the addition of a prime) is not provided with the hole 11 and conical protrusion 10 of the base plate of Figure 2. Instead, there is provided a rectangular metal plate 33 having a fold extending across it close to one of its edges. The metal plate 33 is secured to the base plate 2' on the long axis thereof and close to one of its short edges. The metal plate 33 is secured by its edge portion close to the fold and at its opposite end portion such that, remote from its edge portions, it is spaced from and slopes with respect to the base plate 2'.Within the plate there is provided a keyhole-shaped aperture 34 having an enlarged, rounded portion and a slot portion extending therefrom axially of the metal plate 33, the enlarged, rounded portion being proximal to the fold and the slot portion being distant from the fold.

A cover (not shown) for use with the base plate 2' of Figures 4a and 4b is substantially similar to the cover 3 described with reference to Figure 1, with the peg 20 of that cover being replaced by a peg having an enlarged head spaced from the cover by a shaft of lesser diameter. The sizes of the head and shaft are selected such that the head may pass through the enlarged, rounded portion of the aperture 34 in the metal plate 33, and such that the peg may then be displaced axially of the metal plate 33 such that the shaft passes into the slot portion of the aperture 34, whereupon the head is trapped behind the metal plate 33 by virtue of its being too large to pass through the slot portion. The sloping attachment of the metal plate 33 to the base plate 2' causes the peg to be drawn towards the base plate 2' as it is displaced within the aperture 34. The peg may conveniently be formed by the head of a screw which is screwed into a receiving formation on the cover.

Figure 5 shows a backplate assembly being a second embodiment of the invention. As with the above-described embodiment, the assembly comprises an elongate base plate 40 (illustrated in Figure 6) adapted to be secured to a door or a window 42 by screws 44. A cover 46 is provided which covers the base plate 40 and has an aperture 48 into which a spigot 52 of a handle 50 is received, a washer 54 surrounding the spigot 52 and separating the body of the handle 50 from the cover 46. A rod (not shown) extends from the handle 50, into an aperture 56 in the door or window 42 for operation of a latch mechanism.

A drive unit 58 is located, surrounding the rod, between the cover 46 and the door or window 42 within an aperture in the base plate 40, and is prevented from rotation by flanges 60 upstanding from the base plate 40, the drive unit 58 being operative to exert a torque on the bar which tends to urge the handle towards its inoperative position.

In the present embodiment, there is provided at both of the opposite short end portions of the base plate 40 a turned-over lip 62. Each lip 62 has a first portion which extends away from the main body of the base plate 40 at an angle of approximately 450 from the door. Each lip 62 also has a curled portion extending from the first portion smoothly-curving such that the free end portion of the lip is directed generally towards the centre of the base plate 40 at an angle of approximately 50away from the door or window 42.

The cover 46 has, a generally rectangular recess into its surface which faces towards the door or window bounded by a peripheral flange. Portions of the flange are formed with an undercut 64 formed, for example, by milling. Each undercut portion extends transversely of the long axis of the recess the undercut 64 being at an angle of approximately 670 from the plane of the cover 46.

To assemble the backplate assembly, the base plate 40 is first secured to the window or door 42 by means of the screws 44. The drive unit 58 is then positioned between the flanges 60. Following this, the cover 46 is placed on the base plate 40 such that a first of the lips 62 of the base plate 40 enters the corresponding undercut 64 in the cover 46. The cover is then moved towards the base plate 40 such that the second of the lips 62 touches the wall of the recess in the cover 46 adjacent the undercut 64. The dimensions of the cover 46 and base plate 40 are such that the wall and the second lip 62 touch on the curved portion of the lip 62. The cover 46 is then pushed towards the base plate 40, causing the second lip 62 to deflect inwardly towards the centre of the base plate 40 sufficiently to allow it to enter the undercut 64 on the cover 46, whereupon it springs outwardly by a small amount. The cover 46 is thus retained in position on the base plate 40 by the interaction of the lips 62 and undercuts 64.

Claims

1. A backplate assembly comprising a base plate which is adapted to be secured by fixing screws to a door or window, and a cover which extends over the base plate, has a peripheral flange which extends around the base plate and which cover is releasably retained to the base plate by retention means at the peripheral flange co-operating with an anchorage at the base plate.

2. A backplate assembly according to claim 1 wherein the anchorage at the base plate comprises a retaining shoulder, lug or other location behind or against which the retention means abuts to secure the cover of the base plate.

3. A backplate assembly according to claim 1 wherein the anchorage at the base plate comprises an aperture or recess in which the retention means engages.

4. A backplate assembly according to claim 2 or claim 3 wherein the retention means comprises screw means.

5. A backplate assembly according to claim 4 wherein the screw means comprises at least one grub screw engaged in a threaded hole in the peripheral flange and which when tightened does not project, or not significantly, from or is recessed within the flange, so as to be substantially concealed from view.

6. A backplate assembly according to claim 2 wherein the retention means comprises a projecting flange which abuts against the anchorage.

7. A backplate assembly according to claim 6 wherein the anchorage comprises a resiliently deflectable lip projecting from the base plate and which is caused to be deflected by the flange to allow the flange to pass behind it and then be retained by the lip.

8. A backplate assembly according to any preceding claim wherein the base plate and cover have co-operating parts or formations which interengage to assist in retention of the cover on the base plate.

9. A backplate assembly according to claim 8 wherein the co-operating parts or formations interengage as the cover is being applied to the base plate, and also provide a means of facilitating correct location of the cover on the base plate for the retention means to be engaged with the anchorage.

10. A backplate assembly according to claim 9 wherein the co-operating parts or formations comprise a peg on the cover and a hole in a protruding portion of the base plate protruding towards the cover, the peg engaging in the hole.

11. A backplate assembly according to claim 9 wherein the co-operating parts or formations comprise a headed peg or the like on the cover and a plate fixed with respect to the base plate having a keyhole-shaped aperture in which the headed peg or the like engages.

12. A backplate assembly according to claim 11 wherein the plate fixed with respect to the base plate slopes relative to the base plate such as to cause the headed peg or the like to be drawn towards the base plate as it is displaced within the keyhole-shaped aperture after insertion of the head of the headed peg or the like in the enlarged portion of the aperture.

13. A backplate assembly according to any preceding claim wherein the cover is adapted to have a handle located on it.

14. A backplate assembly according to claim 13 wherein spring loading is provided between the base plate and cover adapted to act upon the handle to rotate the handle to an inoperative position, movement-limiting stops being fixed relative to the base, and a member being provided to be rotatable with the handle and having a projection which moves between the movement-limiting stops to limit the extent of rotation of the handle.

15. A backplate assembly according to claim 13 or claim 14 wherein the cover has a bearing hole which locates a journal of the handle and the margin of which is overlain by a shoulder of the handle at the root of the journal.

16. A backplate assembly comprising a base plate which is adapted to be secured by fixing screws to a door or window, and a cover plate which extends over the base plate and which is adapted to have a handle located on it, and a drive unit operative to urge the handle to an inoperative condition, the base plate having an aperture in which the drive unit is located and retaining formations adjacent to the aperture for retaining and inhibiting rotation of the drive unit relative to the base plate.

17. A backplate assembly according to claim 16 wherein the retaining formations comprise flanges upstanding from the base plate between which the drive unit is a tight-fit.

18. A backplate assembly substantially as described herein with reference to Figures 1 to 3 and 7 of the accompanying drawings.

19. A backplate assembly substantially as described herein with reference to Figures 1 to 3 and 7 as modified by Figures 4a and 4b of the accompanying drawings.

20. A backplate assembly substantially as described herein with reference to Figures 5, 6a and 6b of the accompanying drawings.