Door latch installation

Abstract

A door latch system (1) comprises a latch (10) and rose bases (60A,B) which clamp together against a door panel through a cross-drilling in the door panel by screws 80 engaging in bosses (94) above and below the latch body (12). The latch body is supported in the cross drilling by an adaptor (40) which in turn supports sleeve extensions (90) of the rose bases to prevent the rose bases from turning on operation of the handle knob/levers attached to the rose bases. The sleeve extensions are open, (that is, C-shaped in section) so that the diameter of the parts of the system within the cross drilling can be minimised, whereby the diameter of the rose bases can likewise be kept within desirable limits of size.

Claims

1. A door latch system for installation in a door panel having a cross-drilling and an edge-hole intersecting the cross-drilling, the door latch system comprising: a. a door latch having a face plate and a body, the body having a body axis and including an operation aperture at a desired backset from the face plate, the operation aperture being arranged for rotation in the body about an operation axis orthogonal to said body axis; b. an adaptor to receive the door latch body; c. two handles, each comprising a rose base and lever or knob rotatably disposed in the rose base; and d. a handle spindle having a longitudinal axis, wherein the door latch system is adapted for installation in the door panel by: i) the latch body being configured to be received in the edge-hole with the face plate substantially flush with the edge of the door; ii) the adaptor being configured to fit with a close sliding fit in a door cross-drilling of between 40 and 50 mm, with a passage to receive the latch body so as to support the latch body in the adaptor in the cross-drilling and so as to prevent rotation of the adaptor with respect to the latch body about said operation axis; and iii) the operation aperture and handle spindle being configured so that the handle spindle passes through the operation aperture, whereby said operation axis and longitudinal axis are coincident, and is received in each handle or knob, whereby rotation of the handle or knob results in rotation of the operation aperture about said axes and actuation of the latch, and wherein: cross screws and bosses are provided to clamp the rose bases together, the bosses comprising a sleeve threaded from each end for receiving said cross-screws, each rose base comprising screw holes disposed diametrically opposite one another on either side of said lever or knob, so that said cross screws can be received in the cross-drilling around the latch body, and an extension sleeve formed around each screw hole, the extension sleeves being configured for supporting the bosses when the cross screws are received in the bosses and engaging the adaptor to locate the rose bases rotationally around said axes with respect to the adaptor, wherein said extension sleeves are C-shaped along their section, with an open part facing away from said axes such that a maximum diameter of the part of the handle to be received in the cross-drilling is defined by a boss located in a C-shaped section of an extension sleeve.

2. A door latch system as claimed in claim 1, wherein reception of the boss in each extension sleeve is a close sliding fit to inhibit bending moments between the boss and extension sleeve in a direction of rotation of the rose base about said operation axis.

3. A door latch system as claimed in claim 1, wherein the screw holes are set to either side of a flange around a lever or knob reception bore of the rose base, said flange having a sufficiently large diameter that a cover cap with a corresponding central opening can be manoeuvred around a lever after installation of the system in a door to cover heads of the cross screws.

4. A door latch system as claimed in claim 1, wherein engagement between the extension sleeve of the rose bases and the adaptor is so close to inhibit bending moments between the adaptor and extension sleeve in a direction of rotation of the rose base about said operation axis.

5. A door latch system as claimed in claim 4, wherein the adaptor has notches in its edge to receive said extension sleeves.

6. A door latch system as claimed in claim 1, wherein the latch body has a privacy button operable by a button on one rose base whereby the operation aperture may be rendered unrotatable by the handle or ineffective on rotation of the handle to operate the latch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

(2) FIG. 1 is a perspective exploded view of a latch system in accordance with an aspect of the present invention;

(3) FIGS. 2a to d are respectively a plan view, perspective view, end view and side view of a latch system in accordance with an aspect of the present invention; and

(4) FIG. 3 is a section of the latch system shown in FIGS. 1 and 2, taken on the line III-III in FIG. 2a.

DETAILED DESCRIPTION

(5) FIG. 1 shows a latch system 1 in accordance with one embodiment of the present invention. A latch 10 is known per se and comprises a latch body 12 and an end plate 14. The end plate 14 is round and has a cylindrical section 16 adapted to be received in an edge bore (not shown) in the edge of a door panel (also not shown). The section 16 has knurls 18 adapted to be a press fit in the edge bore if that is appropriately sized. Typically, the section 16 and the edge bore have a diameter of about 25 mm. The end of the latch 10 has the usual latch member 20, adapted to engage a keeper in a door jamb and retain the door closed in known fashion. The latch body 12 has a longitudinal axis X and an operation aperture 22, which is rotatable in the body about an operation axis A which is orthogonal the longitudinal axis X. The operation aperture 22 has a backset B, being the separation of the axis X from the end plate 14. This is typically either 45 mm or 57 mm, depending on the handle (not shown) to be employed with the door.

(6) In a door with an edge bore, a cross drilling (not shown in FIG. 1 but shown at 50 in FIG. 3, in a door panel 52), is provided whereby the axis A of operation aperture 22 is arranged to be coincident with the cross-drilling. In the cross drilling 50, an adaptor 40 is first fitted in a close sliding fit in the cross drilling. It has a latch bore 42 arranged coincident with the latch axis X and with a cross section to receive the latch body (in this case substantially rectangular) when the latch is inserted in the edge bore. The adaptor also has a spindle hole 44 arranged coincident with the latch axis A. The bore 42 and the fitting of the adaptor in the cross drilling support the latch body in the cross-drilling, the support is against vertical movement and against rotation about the X axis. At the same time, the fitting of the latch in the edge bore supports the adaptor and prevents it from rotating about the A axis.

(7) When the latch and adaptor are in place, the operation aperture 22 is adapted to receive in a sliding fit a square-section handle spindle 30, which has a longitudinal spindle axis Y, whereby, when assembled, operation axis A and spindle axis Y are coincident.

(8) Two rose bases 60A,B are provided. As shown more clearly in FIG. 3 each rose base mounts a handle knob 62A or a handle lever 62B. The form of the handle lever or knob are incidental to the present invention and are shown only in dotted lines in FIG. 3, but, whatever their form, they are mounted for (at least limited) rotation in the rose base 60A,B, through a rotary joint 64 comprising a cylindrical stem and flange 66, washer 69 and circlip 70, passing through a circular aperture 74 in the rose base 60A,B. A spring 76, acting between the knob/lever flange/stem 66 and the rose base 60A, B, can be arranged to bias the knob/lever 62A,B to a stop position. The knob/lever 62A,B has a drive aperture 63A,B to receive the ends of the handle spindle 30. The handle spindle passes freely through the spindle hole and though the operation aperture 22, whereby turning of the knob/lever 62A,B results in rotation about the axis Y of the spindle and operation of the operation aperture 22 to withdraw into the latch body 12 the latch member 20.

(9) The rose bases 60A,B each have screw holes 68 to receive two screws 80. The screw holes are diametrically opposed. Their heads 81 are covered by a cap 82 having a central aperture 84. The central aperture needs to be as large as possible because it is intended to fit over the lever 62B. The cap may be screwed onto thread 86 on the rose base. The size of the aperture 84 needs to be large because it limits the design and shape of lever 62B that the latch system can accommodate, unless, that is, it is not required that the screw heads 81 be hidden, which, largely inevitably, must be left exposed where a knob 62A is employed as that will surely not pass through the aperture 84. As a result, the screws 80 need to be on as large a diameter as possible, and yet there is the restriction of the diameter of the cross drilling 50 if the rose base 60A,B is to cover the drilling completely.

(10) In addition there is the requirement to restrain the rose bases from rotation under the effect of continual turning of the knob/lever 62A,B. For this, there are integral extension sleeves 90 that extend from the rose bases 60A,B around the screw holes 68 and are adapted to engage U-shaped slots 92 in the edges of the adaptor 40. The adaptor 40 is conveniently an injection-moulded plastics component. Internally, the extension sleeves are a close sliding fit over a boss 94 that is internally threaded at both ends and receives the screws 80. When they are tightened, the rose bases clamp the door panel around the cross-drilling 50. It is evident that the thickness T of the door panel is a variable parameter and the lengths of the sleeve extensions are such that and allowance L is provided so that the latch arrangement can accommodate door panels of thickness between (T−L) and T, which typically will be in the order of 35-45 mm. The similar dimension L is also left between the screws 80, with sufficient thread provided in the boss to accommodate the thickness variation. The upper limit T of the allowable door panel thickness is of course dictated by the overlap between the screws 80 and the boss 94. However, In FIG. 3, the boss 94 is screwed entirely onto the left-hand screw (in the drawing) and this does not leave more than a few turns of the thread for the right screw, or indeed much overlap between the boss and the right-hand extension sleeve 90. The arrangement could accommodate a wider door thickness, with as much overlap between the threads of the boss and right-hand screw, and between the right-hand extension sleeve and the boss, if the boss was not screwed tightly onto the left-hand screw. However, then, an important interengagement that does limit the door thickness, and is not improved by repositioning of the boss 94, is between the extension sleeves 90 and the adaptor slots 92. These desirably have a significant overlap so that there is less opportunity for lateral displacement between them.

(11) It is apparent that an alternative arrangement could be as shown roughly cross-hatched in FIG. 3 at 80′, where the left-hand screw, sleeve extension and boss are all integrated as part of the rose base 60A. Indeed, both screws, sleeve extensions and bosses on one rose base 60A could be integrated so that, on that rose base, no cap 82 would be required, since no screw heads 81 would be evident. However, this would involve different rose bases 60A,B, which might be undesirable and that could be avoided by having each rose base have one screw, sleeve extension and boss integrated while the other side of the rose base is as currently shown in FIG. 3 (that is with screw hole 68, separate screw 80 and open sleeve extension 90.

(12) Finally, given the desire to have the screws 80 on the maximum dimension possible, the extension sleeves 90 are C-shaped in section, with the open part 90C facing away from the axis Y, whereby the maximum diameter D of the internal parts of the latch system 1 (ie, those parts within the cross-drilling 50) is defined by the position of the screws 80 and the thickness of the boss 94. One reason why the boss 94 may be provided as a separate component (as shown in the drawings), and not be integrated with the rose base 60A, is so that it can be provided in a relatively hard steel, and thereby be rendered thin, whereas the material of the rose bases 60A,B may desirably be of softer less expensive material, such as aluminum or brass. In one embodiment, the dimension D is 43 mm, with the diameter of the cross drilling being 45 mm and the diameter (or minimum dimension) of the rose bases being 49 mm so that, with the cap 82 attached the final diameter is 50 mm.

(13) One benefit of the arrangement whereby the screws 80 and accompanying components are disposed above and below the latch body 12 is that existing latches 10 can be employed. One arrangement has a privacy button 100 that can affect operation of the latch 10. It may be actuated by pressing or turning and serve either to lock the operation aperture 22 (so that the knob/lever 62A,B cannot be turned) or to render its rotation disconnected from the latch member 20 so that that remains in the closed position despite turning of the knob/lever 62A,B. Where the privacy button is to be employed, one rose base 60A,B is provided with an actuator (not shown) to actuate the button 100. This is disposed at right angles (around axis Y) in the rose base and a slot 101 is provided in the adaptor to accommodate it.

(14) Any of the above-described features can be used in any suitable combination with any of the other above-described features, and the present invention is not necessarily limited to the specifically described combinations.

(15) Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

(16) Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

(17) The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.