AU2015252030A1

AU2015252030A1 - Micro-switch box with adjustable support plate

Info

Publication number: AU2015252030A1
Application number: AU2015252030A
Authority: AU
Inventors: Trevor David Leisk
Original assignee: LEISK TREVOR
Current assignee: LEISK TREVOR
Priority date: 2005-07-21
Filing date: 2015-10-28
Publication date: 2017-05-18
Also published as: AU2017202920B2; AU2011201414B2; AU2017202920A8; AU2013216589B2; AU2014274550B1; AU2017202920A1; AU2013216589A1; AU2011201414A1

Abstract

Abstract A micro-switch box for installation in a door frame (122) has a front wall (105, 205), a back wall (103), a top wall (101), a bottom wall (102), two side walls (104; 207, 207A), and a support plate (107, 220). The support plate is independent of the top, back, bottom and side walls. The front wall (105, 205) has an aperture in it through which an end of a bolt of a lock on a door supported on said door frame (122) may pass to actuate a micro-switch (125) mounted on the support plate. The distance separating the support plate (107, 220) from the back wall (103) is adjusted by rotating two horizontal, elongate, externally threaded, cylindrical rod members (1101), each having a head member (1102) at one end thereof. The rod members (1101) pass through respective apertures (1105) in the support plate. They also pass through respective apertures (1106) in the back wall, or the front wall, or a face plate (213). If the apertures (1106) are in the back wall, they may be threaded apertures or clearance apertures for the rod members (1101). In all other cases, the apertures (1105) in the support plate are threaded apertures. A respective retaining member (1103) holds, but does not clamp, each head member (1102) in its position alongside the wall or the face plate or the support plate (as the case may be) through which the rod member passes. The support plate (107, 220) may be mounted on at least one slide member (2217) that is supported by, and is a sliding fit within, a respective pair of channels (2210, 2213) adjacent to a side wall (207, 207A). The micro-switch box may be provided with two face plates (213, 213A), and may include at least one tamper switch (216, 216A) ooFIG I0 /0,9 00g /O/2 /0g1/0 1I0 ~ FIG. 4

Description

2015252030 28 Oct 2015

Regulation 3.2 1 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION (Patent of Addition)

Name of applicant/Nominated Person:

Trevor David Leisk

Address for Service:

Davies Collison Cave, Patent Attorneys 1 Nicholson Street, MELBOURNE, Victoria, 3000.

Invention title: “Micro-switch box with adjustable support plate”

Details of the Patent of the Main Invention:

Australian Patent No. 2005270713.

The following statement is a full description of this invention, including the best method of performing it known to me: 2 2015252030 28 Oct 2015

Technical field.

This invention concerns micro-switch boxes. More particularly, it concerns a modified micro-switch box of a type that is described and 5 claimed in the specification of my Australian patent No. 2005270713. The modified micro-switch box of the present invention was developed for use with, inter alia, an electronic unit for monitoring the lock status of a door. However, the modified micro-switch box of the present invention will be useful in other door locking arrangements. 10

Preliminary note.

In this specification, including the claims, terms implying a direction or a relative position, such as “top”, “bottom”, “front”, “back”, “side”, “horizontally”, “vertically”, “rearwardly”, “upwardly”, “in front of, and the like, will be used in is the sense that these terms have when the unit or component being referred to is positioned as shown in Figures 3, 5 and 7 of the accompanying drawings.

Background to the invention. 20 As noted in the specification of my Australian patent No. 2005270713, in recent years, organisations that have rooms in which sensitive, classified, secret (including trade secret and top secret) information and/or equipment is stored or used, have become aware that (a) special locking arrangements are required to ensure that a door into such a room can be 25 securely locked, and (b) there needs to be some way of monitoring when the door into such a room is no longer locked and when the door has been opened. Accordingly, electrical and electronic circuits have been developed to detect when the extended bolt of a lock has been withdrawn into the body of the lock (that is, the lock bolt no longer locks its associated 30 door) and/or a door has been opened. Such monitoring circuits usually include a mechanism for generating an alarm signal when the door to a 3 2015252030 28 Oct 2015 secure room has been unlocked, and/or opened, by an unauthorised person.

Most companies that provide secure locking arrangements have developed 5 their own special “end of line” for use with such electrical circuits. The “end of line” is understood to be an assembly of electronic components so connected together that they provide a signal to a monitoring location when specified events occur, or specified situations exist. (The specified situation will normally include “door locked’ and “door unlocked” signals.) ίο Each company that has developed an “end of line” regards it as a trade secret, the details of which are not to be made public.

The specification of my Australian patent No. 2005270713 describes a micro-switch box in which a micro-switch and an “end-of-line” of a door is lock monitoring arrangement for a high security room (a “Type 1 secure room”) can be mounted. That micro-switch box is constructed to be strong, and to be mounted within a door frame, where access to the micro-switch box can occur only when the door that is being monitored is open. 20 That micro-switch box has been used, successfully, since shortly after its introduction to the security market ten years ago. I have conceived a modification of my original micro-switch box (as defined by claim 1 of my Australian patent No. 2005270713) that can be incorporated into all realisations of my micro-switch box. 25

Disclosure of the invention.

The modification is the replacement of the support plate for a micro-switch, that, until now, has been rigidly attached to either the top and bottom walls, or the side walls, of the micro-switch box, with a support plate that is 30 adjustable. By adjustable, I mean that the distance between the support plate and the back wall of the micro-switch box can be adjusted (a) to ensure 4 2015252030 28 Oct 2015 that the optimal position of the micro-switch for the end of a lock bolt to contact its actuation plunger or lever is adopted, or (b) to enable the spacing of the actuation plunger or lever of the micro-switch to be changed if a new lock is used on a door and the throw of the bolt of the new lock is 5 different from the throw of the bolt of the original lock

The adjustment is effected by two elongate, externally threaded, cylindrical rod members that (a) operate as a screw, as “screw” is first defined in the Third Edition of the McGraw-Hill Dictionary of Scientific and Technical ίο Terms, published by McGraw-Hill Book Company, 1984, and (b) extend between and through pairs of horizontally aligned apertures in the support plate and also in: (1) the back wall of the micro-switch box; or (2) the front wall of the micro-switch box; or is (3) a face plate attached to the front wall of the micro-switch box. (In principle, more than two such rod members may be used, but in the embodiments described in this specification, a micro-switch box having only two rod members and their aligned apertures are considered.) One of each pair of horizontally aligned apertures is an internally threaded aperture, the 20 thread of which corresponds to the external thread of the rod members. The other of said horizontally aligned apertures is a clearance aperture for the rod members. Each elongate rod member has a “head member” at one end and the adjustment of the position of the support plate is made by rotating the head members using a spanner, a screwdriver, an Allen key, a tube 25 spanner, or a similar rotation device, according to the configuration of the head member of the rod members.

The head member may be positioned behind the back plate of the microswitch box, or in front of the support plate, or in front of the front wall, or in 30 front of the cover plate of the micro-switch box. (If the head member is shaped to fit into the countersunk region of a countersunk aperture in the 5 2015252030 28 Oct 2015 back face of the back wall, or in the front face of the support plate, or in the front face of the front wall or in the front face of the face plate, the head member will be understood to be, respectively, behind the back plate of the micro-switch box, or in front of the support plate, or in front of the front wall, 5 or in front of the face plate of the micro-switch box.) The last three of these four arrangements will be useful if the adjustment of the position of the support plate is required after the micro-switch box has been installed in a doorframe. If the head member is positioned in front of the support plate, or in front of the front wall of the micro-switch box the adjustment device - a ίο screwdriver or the like - may need to be inserted through apertures in the face plate that are aligned with respective elongate rod members. When the head member is positioned adjacent to a face of the back wall, the support plate, the front wall or the face plate, what I have called a “retaining member” is positioned on each rod member adjacent to the other face of the back is wall, the support plate, the front wall or the face plate, to hold - but not clamp - the head member in that position.

Thus according to the present invention, there is provided a micro-switch box for installation in a door frame, for use with a locking arrangement, 20 comprising a box having a front wall, a back wall, a top wall, a bottom wall and two side walls; characterised in that (a) a support plate is provided within the region bounded by said walls, said support plate being independent of said walls; and (b) said front wall has an aperture therein through which an end of a bolt of a lock on a door supported on said door 25 frame may pass to actuate a micro-switch mounted on said support plate; further characterised in that: at least two horizontal, elongate, externally threaded, cylindrical rod members, each of said rod members having a head member at one end thereof, pass through respective apertures in said support plate, and also pass through: 3o (1) respective apertures in said back wall; each of said apertures in said back wall being internally threaded apertures, the thread of 6 which corresponds to the external thread of said rod members passing therethrough; said apertures in said support plate being clearance apertures for said rod members through which said head members cannot pass; and a respective retaining member is positioned on each said rod member adjacent to the face of said support plate that faces said back wall; or (2) respective apertures in said back wall; each of said apertures in said back wall being clearance apertures for said rod members through which said head members cannot pass; and said apertures in said support plate are internally threaded apertures, the thread of which corresponds to the external thread of said rod members passing therethrough; and a respective retaining member is positioned on each said rod member adjacent to the face of said back wall that faces said support plate; or (3) respective apertures in said front wall; each of said apertures in said front wall being clearance apertures for said rod members through which said head members cannot pass; and said apertures in said support plate are internally threaded apertures, the thread of which corresponds to the external thread of said rod members passing therethrough; and a respective retaining member is positioned on each said rod member adjacent to the face of said front wall that faces said support plate; or (4) respective apertures in a face plate that is rigidly attached to said front wall; each of said apertures in said face plate being clearance apertures for said rod members through which said head members cannot pass; and said apertures in said support plate are internally threaded apertures, the thread of which corresponds to the external thread of said rod members passing therethrough; and a respective retaining member is positioned on each said rod member adjacent to the face of said face plate that faces said support plate. 7 2015252030 28 Oct 2015

Rotation of the head member of an elongate rod member, and thus also of the externally threaded rod member, causes the support plate to be moved towards or away from the back wall. 5

Guides may be provided to facilitate the smooth fore-and-aft movement of the support plate.

If the heads of the elongate, externally threaded, cylindrical rod members ίο are positioned in front of the cover plate of the micro-switch box, the support plate may be mounted on a member (that I have called a “slide member”) that can move towards and away from the back wall, in slide guides or channels adjacent to one of the side walls. The slide member is preferably (but not necessarily) a substantially vertical plate, the upper and lower is extremities of which are positioned within the slide guides or channels. The support plate is mounted on the slide member so that, if the support plate is planar, its face that faces the back wall of the micro-switch box is at right angles to the face of the side wall adjacent to which the slide guides or channels are located. The other side wall is then preferably an independent 20 item that forms the micro-switch box by being attached to mounting blocks by screws or bolts. The mounting blocks (there should be at least two mounting blocks; preferably there are four mounting blocks) are attached -preferably by welding - to the top wall or the back wall or the bottom wall of the micro-switch box. Thus this “other side wall” is removable to provide 25 access to the support plate when a micro-switch is to be mounted on the support plate, or an additional piece of equipment is to be installed within, or is to be removed from the interior of, the micro-switch box.

The support plate has two (or more) spaced apart (preferably vertically 30 spaced apart) threaded apertures into which respective elongate, externally threaded, cylindrical rod members, that have passed through respective 8 2015252030 28 Oct 2015 clearance apertures in a face plate of the micro-switch box that is attached to the front wall of the micro-switch box, are screwed.

An additional face plate may be affixed to the face plate through which the 5 externally threaded elongate rod members pass, after any required adjustment of the position of the support plate has been effected, to cover (and thus prevent ready access to) the head members.

Embodiments of the present invention will now be described, by way of ίο example only, with reference to the accompanying drawings.

Brief description of the drawings.

Figure 1 is a partly schematic and partly sectional illustration of a microswitch box installed in a doorframe, the micro-switch box incorporating the 15 present invention.

Figure 2 is a partly schematic and partly vertical sectional view of a microswitch box incorporating the present invention so that adjustment of the position of the support plate can be effected from the front of the micro-20 switch box.

Figure 3 is a partly schematic perspective sketch of the micro-switch box that is similar to the micro-switch box depicted in Figure 2, with a microswitch box mounted on the support plate, and a cover plate configured to 25 allow adjustment of the support plate after the micro-switch box has been installed in a doorframe.

Figure 4 is a partly schematic and partly sectional view of a support plate and bracket combination that permits the present invention to be used when 30 the micro-switch to be mounted on the support plate is a lever type microswitch. 9 2015252030 28 Oct 2015

Figure 5 is an exploded, partly schematic, perspective sketch showing the major components of a micro-switch box that includes the present invention, in which the adjustment of the position of the support plate is effected from the front of a face plate. 5

Figure 6 is a partly schematic side view of the micro-switch box illustrated in Figure 5, with the side wall 207 shown in Figure 5 removed and with some components shown in vertical section. ίο Figure 7 is an exploded, partly schematic, perspective sketch of a modified form of the micro-switch box shown in Figure 5.

Figure 8 illustrates one of many alternative constructions of a support plate mounted on a slide member, for inclusion in a micro-switch box of the type 15 shown in Figures 5 to 7.

Detailed description of the illustrated embodiments.

In this description, where it is practical and convenient, the reference numerals of the features illustrated in the accompanying drawings are the 20 same as the numerals used to designate the same, or similar, features in the drawings of the specification of my Australian patent No. 2005270713.

Figure 1 shows a micro-switch box installed in a door frame 122. The micro-switch box has a top wall 101, a bottom wall 102, a back wall 103 and 25 two side walls 104. A plunger type micro-switch 125, activated by pressure applied to its plunger or button 126, is mounted on a support plate107. Wires 109 from the micro-switch 125, leave the micro-switch box via aperture 115 in the back wall 103 to enter a conduit 116 in the wall on which the doorframe 122 is positioned. 30 A pair of externally threaded, elongate, cylindrical rod members 1101 extend 10 2015252030 28 Oct 2015 through the support plate 107 and the back wall 103. The elongate direction of each rod member 1101 is parallel to the planes of the top, bottom and side walls, and therefore parallel to the elongate direction of the other elongate rod member 1101. Each rod member 1101 passes through a 5 respective clearance aperture 1106 in the back wall 103. Each rod member 1101 is preferably a close but loose fit in its associated clearance aperture 1106. Each rod member 1101 also passes through a respective internally threaded aperture 1105 in the support plate 107. The internal thread of each aperture 1105 corresponds to the external thread of each elongate rod ίο member 1101, so each rod member 1101 has to be screwed into and through the support plate 107. The ends of each rod member 1101 that are positioned behind the back wall 103 terminate at a respective head member 1102. The head members 1102 will normally be formed integrally with their rod members 1101. The dimensions of each head member 1102 are such 15 that the head member cannot pass through the clearance aperture 1106 in the back wall 103.

Each elongate rod member 1101 is held with its head member 1102 closely adjacent to the back wall 103 by a retaining member 1103. If the entire 20 length of the rod member 1101, from the head member 1102 to the other end of the rod member, has an external thread, a convenient, and preferred, retaining member 1103 is a Nylok (“Nylok” is a trade mark) nut, which has a nylon insert. Alternatively, a pair of lock nuts may be used as the retaining member; and if the region of the elongate rod member 1101 that is closest to 25 its head member 1103 is not threaded, the retaining member may be a circlip in a circular groove around the rod member 1101. Other suitable retaining members may be used. The important point is that the rod member 1101 may be rotated by a rotation device such as a spanner or a box spanner (if the head member 1102 has a hexagonal or square side 30 configuration), or a screwdriver (if the surface of the head member that is remote from the threaded portion of the rod member 1101 has appropriate 11 2015252030 28 Oct 2015 slots in it), or an Allen key (if the surface of the head member that is remote from the threaded portion of the rod member 1101 is configured to receive an Allen key). Other rotation devices may be used (for example, a fork having two prongs that engage with respective cavities in the head member). 5

It should be apparent that with the arrangement shown in Figure 1, the distance between the outer surface 126A of the plunger 126 of the microswitch 125 and the inner surface of the back wall 103 can be varied, before the micro-switch box is installed in the doorframe 122, by rotation of the ίο head members 1102, with consequential rotation of the externally threaded elongate rod members 1101. Rotation of the rod members 1101 causes the support plate 107 to move towards or away from, the back wall 103. Such movement will be useful to ensure that the surface 126A of the micro-switch plunger 126 is optimally positioned for actuation when the bolt of the lock of is the door mounted in the door frame 122 is extended, after the door has been closed, to lock the door, and the extended end of the bolt contacts, then applies pressure to, the surface 126A.

It should be apparent that care needs to be taken when rotating, essentially 20 simultaneously, the head members 1102 (and hence the rod members 1101) to ensure that the support plate 107 is moved essentially uniformly at each internally threaded aperture. To assist in such uniform movement, guide members that project from the side walls 104 of the micro-switch box and enter grooves or cut-away sections at the edges of the support plate, may be 25 included in the micro-switch box. An example of the use of such guide members is included in the embodiment illustrated by Figure 3, which is described below.

Turning now to Figures 2 and 3, the distance between the support plate 107 30 and the back wall 103 of the micro-switch boxes depicted in these two Figures is adjustable from the front of the micro-switch box. In these 12 2015252030 28 Oct 2015 embodiments, each of the back walls 103 has two internally threaded apertures 2105, into which, and through which, respective externally threaded, elongate, cylindrical rod members 1101 are screwed. Each rod member 1101 also passes through a respective clearance aperture 2106 in 5 the support platel 07. A respective head member 1102 of each elongate rod member 1101 is located adjacent to the face of the support plate 107 that faces away from the back wall 103, and is held in that location by retaining means 1103. Various configurations of the head members 1102, and the variety of possible retaining members 1103, that may be used, have been ίο described above.

It should be apparent that essentially simultaneous rotation of the head members 1102 using a suitable rotation device (as described above) will cause the support plate 107 to move towards or away from the back wall 15 103. In the embodiment of Figure 3,to facilitate the uniform movement of the support plate when its position is being adjusted, a respective guide member 2103 is mounted on each sidewall 104. The support plate 107 has cut away sections 2104 that have the same shape as the guide members 2103. A coating of a low friction material may be applied to the outer surface of each 20 guide member 2103.

If an adjustment of the position of the support plate 107 is required after the micro-switch box has been installed within the frame of a door (for example, because a new door lock, having a bolt with a throw that is different from the 25 throw of the bolt of the original lock, is replacing the original door lock), the arrangement shown in Figure 3 will be used. This arrangement requires the conventional face plate 110 to br modified. The modification is the inclusion of additional apertures 1107. Each aperture 1107 is aligned with a respective elongate rod member 1101, so that a screwdriver, tube spanner, 30 Allen key or the like may be passed through an aperture 1107 to engage with, and rotate, the head member 1102 of the aligned rod member 1101. 13 2015252030 28 Oct 2015

Careful rotation of the head members by the rotation device enables the spacing of the support plate 107 from the back wall 103 to be adjusted.

It is possible for a lever type micro-switch to be mounted on the support 5 plate of a micro-switch box and for a similar adjustment of the position of the support plate to be undertaken. To enable this, the support plate may be modified as shown in Figure 4. This support plate 107 has a right-angled bracket 1112 mounted on it with one arm of the bracket 1112 adjacent to the outer surface of the support plate and with the other arm of the bracket 1112 ίο extending outwardly from the support plate. The lever type micro-switch 108 can be mounted (as shown in Figure 4) on the arm of the bracket 1112 that is orthogonal to the plane of the front surface of the support plate 107.

The support plate 107 shown in Figure 4 has apertures 1108, which will be is internally threaded apertures if the adjustment of the position of the support plate 107 is from behind the back wall 103 of the micro-switch box, as described above with reference to Figure 1. But if the adjustment of the position of the support plate 107 is from the front of the micro-switch box, the apertures 1108 will be clearance apertures. An additional aperture 1109 20 may be required in the support plate to permit wires from the micro-switch 108 to be passed behind the support plate 107 and enter the aperture 115 in the back wall 103 of the micro-switch box.

The micro-switch box shown in Figures 5 and 6 includes the present 25 invention and some box security features. In this micro-switch box, the front wall 205 comprises two spaced apart, co-planar, vertical plates, one extending downwardly from the horizontal top wall 101 and the other extending upwardly from the horizontal bottom wall 102. One of the side walls (side wall 207) is removable from the assembly of the top wall 101, the 30 bottom wall 102 and the back wall 103. When the micro-switch box is in use, this side wall 207 is held in place by screws 209 that pass through 14 2015252030 28 Oct 2015 respective countersunk apertures 210 to engage with threaded apertures or cavities 228 in respective block inserts (mounting blocks) 208 mounted at or near the meeting of the top wall 101 with the back wall 103, and at or near the meeting of the top wall with the upper part of the front wall 105, and at or 5 near the meeting of the bottom wall 102 with the back wall 103, and at or near the meeting of the lower part of the front wall 105 with the bottom wall 102. (It is not essential for four mounting blocks to be used to secure the side wall 207 in position on the micro-switch box. Fewer than four mounting blocks may be used; more than four mounting blocks may be used. Also, ίο the mounting blocks need not be in the positions shown in Figure 5; they may be attached - for example, by welding - at any suitable location on the top, bottom, front and back walls of the micro-switch box.) A reader familiar with the drawings of the specification of my Australian is patent No. 2005270713 will recognise a certain similarity between the construction of the micro-switch box shown in the present Figure 5 and the micro-switch box construction illustrated by Figure 6 of the specification of patent No. 2005270713. 20 Reverting now to present Figures 5 and 6, a tamper switch 216, having an activation lever 217, is mounted on the back wall 103 near the mounting block 208. The tamper switch 216 can be mounted at any convenient position on the back wall 103, or on the top wall 101, or on the front wall 105, or on the bottom wall 102. The important point is that if circuitry associated 25 with the tamper switch 216 is to generate a tamper signal if and when the side wall 207 is removed, the tamper switch lever 217 must be closed when the side wall 207 is screwed into place, but opened when the side wall 207 is removed. 30 Two elongate, spaced apart, horizontal channel-forming members 2210 and 2213 are rigidly attached (for example, by welding) to the other side wall 15 2015252030 28 Oct 2015 207A. These channel forming members have a generally L-shaped vertical cross-section. The upper channel-forming member 2210 comprises an elongate horizontal arm 2211, having a small but uniform width, and an elongate vertical arm 2212 extending downwardly from the edge of the arm 5 2211 that is remote from the side wall 207A. The lower channel forming member 2213 has a similar construction, with an elongate horizontal arm 2214, having a small but uniform width, and an elongate vertical arm 2215 extending upwardly from the edge of the arm 2214 that is remote from the side wall 207A. These channel forming members 2210 and 2213, with the ίο side wall 207A, form upper and a lower spaced apart horizontal channels that are adjacent to the side wall 207A. An alternative way of forming these channels is to rigidly attach two elongate channel members having a generally U-shaped cross-section, to the side wall 207A (as shown in Figure 7). 15 A “slide member” 2217, that in the embodiment illustrated in Figure 5 comprises a vertical plate, is supported by, and is a close sliding fit in, the channels created by the channel members 2210 and 2213. A support plate 220 for a micro-switch 125 is securely mounted on the slide member 2217. 20 In this embodiment, the support plate and the slide member are both planar plates, so the plane of each surface of the support plate 220 is orthogonal to the plane of each face of the slide member 2217. Preferably, the support plate 220 is welded to the slide member 2217, but other rigidly attaching arrangements may be used. For example, a bracket similar to the bracket 25 1112 shown in Figure 4 may be rigidly attached to the slide member 2217 with the support plate 220 rigidly attached to the arm of the bracket that extends, flange-like, from the slide member.

The support plate 220 has a pair of internally threaded apertures 1105 that 30 are spaced apart vertically, one above and one below a micro-switch mounting aperture in the support plate (in Figures 5 and 6, a micro-switch 16 2015252030 28 Oct 2015 125 is shown mounted on the support plate using the mounting aperture). A first face plate 213 is rigidly attached to each part of the front wall 205 (for example, by welding). The first face plate 213 has a rectangular aperture 5 212 (this aperture need not be rectangular) through which the bolt of a lock may pass. The face plate 213 has a pair of outer apertures 215 in the end regions of the face plate. The apertures 215 correspond to the apertures 114 in the Figure 3 embodiment, in that they are countersunk apertures to enable the assembled micro-switch box to be securely attached to the door ίο frame within which the micro-switch box is to be mounted using screws 117.

The first face plate 213 has a pair of inner apertures 1106. The centres of this pair of inner apertures are spaced apart a distance equal to the distance between the centres of the pair of threaded apertures 1105 in the support is plate 220. The apertures 1106 are countersunk. Respective elongate, externally threaded, cylindrical rod members 1101, each having a respective head member 1102, can pass through the apertures 1106. The head members 1102 are tapered to fit into the countersunk regions of the apertures 1106, but the head members cannot pass through these 20 apertures. A respective retaining member 1103, as described above, is used to hold (but not clamp) each head member 1102 within the countersunk region of its associated aperture 1106. In this instance, since, as shown in Figures 5 and 6, the rod members 1101 are not externally threaded over their entire length, circlips are the preferred form of restraining 25 members.

The ends of the threaded rod members 1101 that are remote from the head members 1102 are screwed into respective threaded apertures 1105 in the support plate 220. So essentially simultaneous rotation of the head 30 members 1102, and thus of the externally threaded rod members 1101, using a screwdriver or an Allen key (depending on the conformation of the 17 2015252030 28 Oct 2015 head members) will cause the support plate to move towards or away from the back wall 103 of the micro-switch box.

Additional security measures have been incorporated into the micro-switch 5 box illustrated in Figures 5 and 6. In particular, a second tamper switch 1216 is mounted on the top wall 101 of the micro-switch box. The activation lever of this tamper switch 1216 is controlled by the position of a pin 2219 that extends horizontally from a second face plate 213A. Typically, the pin 2219 is welded in position on the second face plate 213A. When the micro-lo switch box has been installed in a door frame and the face plate 213 has been securely attached to the door frame, the second face plate 213A is mounted on the first face plate 213 by screws (for example, grub screws) that extend through respective apertures 2221 and are screwed into respective internally threaded apertures in the first face plate 213. When is this action is taken, the pin 2219 passes through a clearance aperture 2222 in the first face plate 213 and through an aligned aperture 2223 in the upper part of the front wall 105, to activate the lever of the tamper switch 1216. If and when the second face plate is removed, the pin 2219 ceases to activate the lever of the tamper switch 1216 and circuitry associated with this tamper 20 switch creates an alarm signal. Because the apertures 1106 and 215 in the first face plate 213 are countersunk apertures, the second face plate 213A lies flat over the first face plate 213, and hides both the apertures 215 and 1106, thus preventing access to the heads of the screws and rod members the have passed through these apertures. 25

To assemble the micro-switch box shown in Figures 5 and 6, either (a) the side wall 207A is a separate unit that has the same construction as the side wall 207, and the combined slide member 2217 and support plate 220 are placed in the channels of side wall 207A before side wall 207A is attached to 30 the box by screws into mounting blocks, in the same manner as described above with reference to side wall 207, or (b) the combined slide member 18 2015252030 28 Oct 2015 2217 and support plate 220 are placed in the channels of side wall 207A before the front wall sections 205 are folded into position.

Figure 7 depicts the components of a micro-switch box that is similar to that 5 illustrated in Figures 5 and 6. The main difference is that the two parts of the front wall 205 of the micro-switch box extend upwardly from the top wall 101 and downwardly from the bottom wall 102. They may be short wall parts, for which the removal of small pieces of the door frame into which the microswitch box is to be installed is required so that the first face plate 213 can fit ίο snugly in or on the door frame, or they may extend to be aligned with the upper and lower edges of the first face plate 213. In view of the description, above, of the embodiment of Figures 5 and 6, it is believed that a detailed description of the Figure 7 embodiment is unnecessary. It should be noted, however, that in the Figure 7 embodiment, the combined slide member 2217 is and support plate 220 can placed in the channels 3210 and 3213 on the side wall 207A after the micro-switch box has been assembled, and it is not necessary for the side wall 207A to have the same construction as the side wall 207. 20 A modification of the micro-switch boxes illustrated in Figures 5, 6 and 7, that is not depicted in these Figures, is the attachment of two slide members to the support plate, one on each side of the support plate. With this modification, a pair of horizontal channels, within which a slide member can slide, will be required adjacent to each side wall of the micro-switch box. 25

Some of the features included in Figures 5, 6 and 7 may be included in the other illustrated micro-switch boxes. For example, a second face plate may be used with the embodiment illustrated in Figure 3. The second face plate will be attached to the face plate 110 in the same manner as the face 30 second face plate 213A is mounted on the face plate 213 in the embodiments illustrated in figures 5,6 and 7, to cover the head of the screw 2015252030 28 Oct 2015 19 that attaches the face plate 110 to the dor frame. Also, a support plate and slide member combination may be used in the other embodiments if a pair of horizontal channels is provided adjacent to one of the side walls of the micro-switch box. And, of course, one or more of the side walls of the other 5 embodiments may be detachable and one or more tamper switches may then be incorporated into the other embodiments.

Figure 8 has been included to emphasise the fact that, in the embodiments shown in Figures 5,6 and 7, there are many ways in which the combination ίο of the support plate 220 and the slide member 2217 may be configured. In addition, Figure 8 shows that the threaded apertures 1105 in the support plate need not be in vertical alignment. Of course, the positions of the apertures 1106 in the first face plate will have to correspond with the positions of the threaded apertures 1105. 15

Locksmiths and security experts will appreciate that examples only of micro-switch boxes constructed in accordance with the present invention have been described in this specification, and that variations in or modifications to the construction of the micro-switch boxes may be made without departing from the present inventive concept, as set out in the following claims.

Claims

The claims defining the invention are as follows.

1. A micro-switch box for installation in a door frame, for use with a locking arrangement, comprising a box having a front wall, a back wall, a top wall, a bottom wall and two side walls; characterised in that (a) a support plate is provided within the region bounded by said walls, said support plate being independent of said walls; and (b) said front wall has an aperture therein through which an end of a bolt of a lock on a door supported on said door frame may pass to actuate a micro-switch mounted on said support plate; further characterised in that: at least two horizontal, elongate, externally threaded, cylindrical rod members, each of said rod members having a head member at one end thereof, pass through respective apertures in said support plate, and also pass through: (1) respective apertures in said back wall; each of said apertures in said back wall being internally threaded apertures, the thread of which corresponds to the external thread of said rod members passing therethrough; said apertures in said support plate being clearance apertures for said rod members through which said head members cannot pass; and a respective retaining member is positioned on each said rod member adjacent to the face of said support plate that faces said back wall; or (2) respective apertures in said back wall; each of said apertures in said back wall being clearance apertures for said rod members through which said head members cannot pass; and said apertures in said support plate are internally threaded apertures, the thread of which corresponds to the external thread of said rod members passing therethrough; and a respective retaining member is positioned on each said rod member adjacent to the face of said back wall that faces said support plate; or (3) respective apertures in said front wall; each of said apertures in said front wall being clearance apertures for said rod members through which said head members cannot pass; and said apertures in said support plate are internally threaded apertures, the thread of which corresponds to the external thread of said rod members passing therethrough; and a respective retaining member is positioned on each said rod member adjacent to the face of said front wall that faces said support plate; or (4) respective apertures in a face plate that is rigidly attached to said front wall; each of said apertures in said face plate being clearance apertures for said rod members through which said head members cannot pass; and said apertures in said support plate are internally threaded apertures, the thread of which corresponds to the external thread of said rod members passing therethrough; and a respective retaining member is positioned on each said rod member adjacent to the face of said face plate that faces said support plate.
2. A micro-switch box as defined in claim 1, in which said support plate extends substantially across the internal width of the micro-switch box; each side wall has a horizontal guide member extending from its internal face; and said support plate has a piece removed from each side edge thereof; the dimensions of said removed pieces being such that said support plate is able to slide on said guide members.
3. A micro-switch box as defined in claim 1, including a pair of horizontal channels adjacent to the interior face of each side wall; and said support plate is rigidly attached to a slide member that is operably supported by and is a slide fit within said pair of channels.
4. A micro-switch box as defined in claim 1, including a respective pair of horizontal channels adjacent to the interior face of each side wall; and said support plate is rigidly attached to a pair of slide members; each slide member being operably supported by and being a sliding fit within a respective one of said pair of channels.
5. A micro-switch box as defined in any one of claims 1 to 4, including a face plate that is attached to and covers said front wall; said face plate having a first aperture therein which is dimensioned and positioned to permit a bolt of a lock to pass therethrough to contact a plunger or lever of a microswitch mounted on said support plate; said face plate having two second apertures in respective end regions of said face plate, to enable said face plate to be mounted on said door frame by respective screws that pass through said second apertures.
6. A micro-switch box as defined in claim 5, in which said rod members extend through clearance apertures in said support plate and the head members of said rod members are positioned adjacent to the outer face of said support plate; and in which said face plate has a pair of third apertures that are aligned with said head members of said rod members and permit access by a rotation device to said head members.
7. A micro-switch box as defined in any one of claims 1 to 4, in which a face plate is rigidly attached to said front wall; said face plate has a first aperture therein that is dimensioned and positioned to permit a bolt of a lock to pass therethrough to contact a plunger or lever of a micro-switch mounted on said support plate; said face plate has two second apertures in respective end regions of said face plate, to enable said face plate to be mounted on said door frame by respective screws that pass through said second apertures; and said rod members extend, respectively, through a pair of third apertures in said face plate through which the head members of said rod members cannot pass; said third apertures being aligned with threaded apertures in said support plate;
8. A micro-switch box as defined in claim 6 or claim 7, in which said face plate is a first face plate; including a second face plate having an aperture therein which is dimensioned and positioned to permit a bolt of a lock to pass therethrough; said second face plate being adapted to fit over said first face plate so that said aperture in said second face plate is aligned with the first aperture of said first face plate and said second apertures in said first face plate are covered by said second face plate.
9. A micro-switch box as defined in any preceding claim, in which at least one of said side walls is detachable from said micro-switch box.
10. A micro-switch box as defined in claim 9, in which at least one tamper switch is included in said micro-switch box.