"a mounting plate for an alarm device"

Abstract

A mains-powered device mounting plate (1) is for mounting of a fire alarm device to a ceiling with a mains wiring connection. The mounting plate has a generally circular body (2) with holes (4) for affixing to a ceiling, and an aperture (25) for training of wires through the plate body. A terminal block (20) is located next to this aperture and has terminals (30, 50, 70, 100) having a wiring interface (26) with openings (33, 53, 73, 103) to receive terminations of wires that have been trained through said aperture, and a device interface (22) with terminal connectors (46, 66, 86, 116) for electrical engagement with device connectors (1001) in a sliding action. Each terminal has multiple wiring interface openings (33, 35, 35) and associated wiring connectors (200) so that up to three wire terminations of the same potential or signal can be individually engaged in a single terminal (30, 50, 70, 100).The wiring interface (26) is sloped for ease of access, the individual terminals may be separated, and they may be collectively or individually released (31, 32) from the plate body (2). There is an individual actuator rod (41, 42, 43) with an exposed slot in the top face of the terminal for individual release of each wiring interface connector, by pressing down against a leaf spring contactor (223).

Description

[0001] “A Mounting Plate for an Alarm Device”

[0002] Introduction

[0003] The present invention relates to a mounting plate for a wall or ceiling mounted alarm device such as a smoke, fire, or gas sensor alarm device.

[0004] It is known to provide a mounting plate for mounting to a ceiling or wall and which allows an alarm device to be slid into position on the mounting plate with both mechanical and electrical inter-connection in a convenient manner. This allows the electrician to do the wiring without the alarm device in place, allowing easy access to the wiring terminals and mechanical securing of the plate to the ceiling. An example is described in EP1045354 (E.I. Technology Ltd.). US2008 / 0032566 (Walter et al) describes a terminal block for connecting electrical conductors, with first and second clamping spring elements.

[0005] A problem with smoke alarm devices is that there can be a log of air flow in attic and ceiling spaces, resulting in an undesirable amount of air flow into the area around the smoke detectors. This poses a risk of adversely affecting the response time to presence of smoke in a room. DE19641846 (WECO Wester) describes a multi-level terminal for a printed circuit board.

[0006] The present invention is directed towards providing improvements on such a mounting plate, to allow more versatile electrical inter-connection and more convenient installation.

[0007] Summary of the Invention

[0008] We describe a mains-powered device mounting plate, the mounting plate comprising:

[0009] a body with features for affixing to a substrate such as a ceiling,

[0010] an aperture in the body for training of wires through the body, and

[0011] a terminal block comprising:

[0012] a plurality of terminals each comprising:

[0013] a wiring interface with openings to receive terminations of wires that have been trained through said aperture in the body, said openings of the terminals providing a wiring interface,

[0014] terminal conductors with wiring connectors aligned with said openings, and a device interface with terminal connectors for electrical engagement withdevice connectors in a sliding action, said connectors of the terminals providing the device interface.

[0015] In some preferred examples, each terminal comprises a plurality of wiring interface openings and associated wiring connectors so that a plurality of wire terminations of the same potential or signal can be individually engaged in a single terminal.

[0016] In some preferred examples, the wiring connectors are shorted together by a unitary conductive support which also supports the device interface terminal connectors.

[0017] In some preferred examples, the wiring interface has a face with said openings and said face is sloped at an acute angle to a plane of the mounting plate body and / or to a plane of the aperture through which the wire terminations are trained.

[0018] In some preferred examples, at least some of said terminals each has a staggered arrangement of wiring interface connectors, and they are preferably equidistant from a front surface of the terminal interface.

[0019] In some preferred examples, at least some of the wiring interface connectors comprises a clamp with a sloped leaf spring to allow push engagement of a wire termination with stiffness of a single wire.

[0020] In some preferred examples, at least some of the connectors have a leaf spring for a normally closed position.

[0021] In some preferred examples, at least some of the terminals each comprises an actuator rod each associated individually with a connector to individually release a single connector by way of a pressing action of the actuator rod against the connector.

[0022] In some preferred examples, at least some wiring interface connectors comprises a tab linked with the leaf spring so that pressing of the tab causes a leaf spring contactor to release.

[0023] In some preferred examples, the tab is laterally of the leaf spring contactor.In some preferred examples, at least some actuators each comprises an exposed button with an indentation.

[0024] In some preferred examples, the button is in a top surface of the terminal.

[0025] In some preferred examples, the terminal block includes a dummy terminal which is insulating and is mounted between two terminals to provide additional insulation between said terminals.

[0026] In some preferred examples, the dummy terminal has indicia in a top surface to provide guidance for an installer.

[0027] In some preferred examples, said indicia comprises a length indicator for indicating in a direction aligned between the wiring interface and the device interface a distance for exposure of wire at a termination.

[0028] In some preferred examples, the terminal block comprises clips for releasable engagement with the plate body.

[0029] In some preferred examples, the terminals are separable, and each has at least one clip for releasable engagement with the plate body and features for releasable engagement with each other.

[0030] In some preferred examples, the features include protrusions such as ribs for snap-fitting into corresponding recesses such as grooves of adjoining terminal housings.

[0031] In some preferred examples, at least one terminal comprises a channel housing a conductor support for a device interface terminal connector.

[0032] In some preferred examples, the channel and the conductor have matching cross-sectional areas to restrict or block passage of air through the channel.

[0033] In some preferred examples, the mounting plate further comprises a cover having a top wall and side walls configured to surround the terminal block and said aperture in the body, and to seal against the block and the body.

[0034] In some preferred examples, the cover comprises a plurality of resilient seals anchored in the coverwalls and configured to press against external surfaces of the terminal block and surfaces of said body.

[0035] In some preferred examples, the seals are arranged to engage across a top surface of the block and side walls of the block so that the cover forms a seal around the block to prevent air from the aperture from flowing around the block towards the device interface.

[0036] In some preferred examples, said channels and said cover seals provide a sealed chamber around the body aperture.

[0037] In some preferred examples, at least some of said seals each comprises a base anchored in a cover wall and a protruding elongate ridge.

[0038] In some preferred examples, the cover is configured to engage the block adjacent the device interface in a pivoting action with at least one block feature retaining a cover feature so that the cover presses a seal against the block across the device interface.

[0039] In some preferred examples, the cover and the body have inter-engaging snap fit fasteners for snap fitting at an end of the cover closest to the wiring interface.

[0040] In some preferred examples, the cover comprises a tongue arranged to fit in an aperture of the body adjacent a snap-fit fastener to assist accurate location of the cover for seal engagement.

[0041] We also describe an alarm device assembly comprising a mounting plate of any example described herein, and an alarm device configured to be physically and electrically mounted to the mounting plate.

[0042] In another example we describe a mains-powered device mounting plate, the mounting plate comprising:

[0043] a body with features for affixing to a substrate such as a ceiling,

[0044] an aperture in the body for training of wires through the body,

[0045] a terminal block, and

[0046] a cover having a top wall and side walls configured to surround the terminal block and said aperture in the body, and to seal against the block and the body,

[0047] wherein the terminal block comprises a plurality of terminals, each terminal comprising:a wiring interface with a plurality of openings to receive terminations of wires that have been trained through said aperture in the body, wherein the wiring interface has a face with said openings and said face is sloped at an acute angle to a plane of the mounting plate body and / or to a plane of the aperture through which the wire terminations are trained;

[0048] wiring connectors each for an opening so that a plurality of wire terminations of the same potential or signal can be individually engaged in a single terminal, a device interface with terminal connectors for electrical engagement with device connectors in a sliding action,

[0049] terminal conductors with said wiring connectors aligned with said openings, wherein the wiring connectors are shorted together by a unitary conductive support which also supports the device interface terminal connectors.

[0050] Detailed Description of the Invention

[0051] The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which:

[0052] Fig. 1 is a perspective view of a mounting plate of the invention, in this case for a smoke alarm device having a round shape in plan,

[0053] Fig. 2 is a perspective view of the mounting plate with a cover removed from a terminal block of the plate,

[0054] Fig. 3 is an enlarged perspective view of the terminal block, and Fig. 4 is a perspective view of the block from the other side, and Fig. 5 is a sectional plan view of the terminal block, the section being across parallel to the top surface,

[0055] Fig. 6 is a perspective view of the metal conductive clamp assembly of the live terminal,

[0056] Fig. 7 is a perspective view of the metal conductive clamp assembly for the neutral terminal,

[0057] Fig. 8 is a cross-sectional view through the neutral terminal, showing the release actuatorsengaging the release tabs on the conductive clamp assembly;

[0058] Fig. 9 is a cross-sectional view through the neutral terminal, in this case also showing a wire termination engaged;

[0059] Fig. 10 is a top perspective view of the terminal block cover, and Fig. 11 is an underneath perspective view;

[0060] Fig. 12 is a perspective cut away view in the longitudinal direction through the block and the cover with the cover in place, and Fig. 13 is a top plan sectional view, these views showing seals in particular detail; and

[0061] Fig. 14 is a diagram illustrating the manner of placing the cover in place so that it positively engages the body and applies pressure to the seals for air flow blockage.

[0062] A mounting plate of the invention is for physically affixing to a ceiling or other base and to allow mains wiring to pass through it and be connected to a terminal block at a wiring interface. The other side of the terminal block has a device interface which makes electrical connections by an alarm device being slid into engagement with, for example, electrical spades on the device engaging in spring sockets in the terminal block. The terminal block has terminals each with a conductor between the wiring interface and the device interface. At a general level, and in terms of how the alarm device is connected to the base the arrangement is the same as is described in our prior patent no. EP 1045354.

[0063] Referring to Figs. 1 and 2 a mounting plate 1 comprises a generally disc-shaped body 2 with a ceiling-engaging rim 3 (and ribs, not shown, on the rear side) and holes 4 for fastening screws to mount to a ceiling or other base. The mounting plate body 2 also has a mechanical latch 5 and four apertures 6 for engagement with tabs of an alarm device housing for mechanical engagement as is known from EP1045354. The mounting plate further comprises a terminal block 20 for electrical connection with the alarm device in a sliding action. Most of the block 20 is covered by a cover 21, but the cover 300 leaves exposed a device interface 22 to allow insertion of spades 1001 of a mating connector 1000 of an alarm device (not shown). The cover 300 has an end 317 for mechanical engagement to the base body 2. Also, it has a front flange 323 on the device interface end, also for assisting with mechanical engagement, as described in more detail below with reference to Figs. 10 to 14.The invention also includes an alarm device assembly comprising the mounting plate of any example and an alarm device having a terminal 100 and being configured to be physically and electrically mounted to the mounting plate.

[0064] Fig. 2 shows the mounting plate 1 with the cover 300 removed. This is the situation while the electrician is making the wiring connections during installation with wire terminations which are trained through a hole in the ceiling and an aperture 25 in the mounting plate body 2. Removal of the cover 300 exposes a wiring interface 26 which is advantageously sloped, forming an acute angle relative to a plane of the aperture 25 (and of the body 2). This allows convenient access as the interface 26 is visible to the electrician in a field of view which is approximately normal to the body 2. This is particularly convenient for wiring the mounting plate to a ceiling. Fig. 2 also shows a receiver 15 for a snap-fit latch of the cover and a locating hole 16 to assist with positioning of the cover. The block 20 has a device-side flange 17, also to assist with positioning of the cover in place.

[0065] The terminal block 20 is shown more clearly in Figs. 3 to 5. It comprises four terminals each having its own plastics moulded casing, and there is an additional “terminal” which does not perform any electrical function but is rather a dummy for the purposes of allowing an additional current-carrying terminal to be inserted if needed and otherwise it provides markings to ease installation, as described in more detail below. The terminals are set out as follows.

[0066] ANeutral terminal 30 has a plastics body 38 with clips 31 and 32 for engaging the body 2, allowing it to be temporarily removed if desired. Removal can be individually or together with the other terminals as all of the other terminals have equivalent clips. However, it is envisaged that in the vast majority of times it would be all together. The clip 31 is longer and so can be opened with use of a flat-headed screwdriver. The part of the wiring interface 26 in the terminal 30 comprises three connector openings 33, 34, and 35 in order from the body 2 distally, in a sloped wall of the terminal housing 38. Across the top surface there is a test probe contact access aperture 36 and a set 37 of actuator rods each associated with a single connector opening 33, 34, or 35. For electrical engagement with the spades 1001 of the alarm device, there is a resilient receptacle or socket 46 with a splayed mouth, as is known per se in the art. The body 38 of the terminal 30 has an opening 47 with tapered sides 48 to guide entry of the spade 1001.

[0067] Also, the body 38 has multiple side protrusion bosses or ribs 39 extending distally from the baseand being configured for snap-fitting into a corresponding slot of the adjoining terminal body.

[0068] The wiring interface 26 is only used by the electrician during installation and is then covered by the cover 300. Subsequently the only exposed part of the terminal block 20 is the device interface 22 with its resilient sockets.

[0069] An Earth terminal 50 has clips 51 and 52 on a plastics body 58 for the same purposes as the clips 31 and 32. The wiring interface 26 comprises three connector openings 53, 54, and 55 in this housing in order from the body 2 distally, in a sloped wall of the terminal housing 58. Across the top surface there is a test button opening 56 and a set 57 of actuators. There is also a socket 66 and an opening 67 with tapered surfaces for the same purposes as the items 46 and 47. There is an elongate protrusion 59 for the same purpose as the protrusion 39.

[0070] The next terminal is an Interconnect terminal 70 having a plastics body 78 with clips 71 and 72 equivalent to the clips 31 and 32. The wiring interface 26 comprises three connector opening 73, 74, and 75 in order from the body 2 distally, in a sloped wall of the terminal housing 78. Across the top surface there is a test button opening 76 and a set 77 of actuators. Again, there is a resilient socket 86 and an associated opening 87 configured similarly to the openings 47 and 67. There is an elongate protrusion 79 for the same purpose as the protrusion 39.

[0071] A dummy terminal 90 provides an additional insulating buffer between the interconnect terminal 70 and a Live terminal 100. Also, it provides a distance indicator 91 on its top surface to act as a guide for paring of the wire insulation to the correct extent for insertion into the terminals 30, 50, 70, and 100 of the copper exposed terminations by the electrician during installation. There is an elongate snap-fitting protrusion 99 for the same purpose as the protrusion 39.

[0072] The Live terminal 100, has clips 101 and 102 equivalent to the clips 31 and 32. There are three connector openings 103, 104, and 105 in order from the body 2 distally, in a sloped wall of the terminal housing 108. Across the top surface there is a test button opening 106 and a set 107 of actuators. There is a socket 116 and associated opening 117 akin to the other such openings. There is an elongate protrusion 109 for the same purpose as the protrusion 39, except in this case it is snap-fitted into a terminal block side wall 28.

[0073] Fig. 6 shows a conductor assembly 150 within the Live terminal 100, which is entirely of metal shorted together to form a single conductive unit with a support structure 210 supportingterminati on-receiving clamps 200 on the wiring interface side and the resilient socket 116 on the device interface side. There are three clamps 200, one for each connector opening 103, 104, and 105. The clamps 200 are staggered according to the angle of inclination of the wiring interface 26, and each clamp 200 has, in order distally (from the body 2), a base 220, a bend 221, an intermediate portion 222, a contactor 223, and an actuator tab 224 laterally of the contactor 223. The contactor 223 is biased upwardly against a plate, item 225 for the lower clamp 200, item 226 for the next clamp 200, and item 227 for the top clamp 200. Each clamp 200 is overall in the form of a leaf spring, with the base 220 providing an anchorage for spring force to be applied upwardly by the contactor 223 against the relevant plate 225 / 226 / 227. In each clamp 200 the actuator tab 224 is laterally of the contactor 223 and for alignment with an actuator as described below with reference to Fig. 8.

[0074] The support structure 210 has a tab 211 positioned to be accessible via the test opening 106 in the top of the terminal 100. The Interconnect terminal 50 has a conductor assembly 150 also.

[0075] Fig. 7 shows a conductor assembly 250 inserted within the Neutral terminal 30. It also has a staggered arrangement of three clamps 200, and it has a support structure 260. In this case the conductor assembly 250 has both of the device-side sockets 46 and 66. The socket 46 is for Neutral, and the socket 66 is for a Battery spade from the alarm device. Once this battery spade and the Neutral spade of the alarm device are shorted by the conductor assembly 250, the backup battery power circuit of the alarm device is automatically closed, effectively turning it on.

[0076] Referring to Figs. 8 and 9 sections through the terminal 30 are shown, the sections being normal to the plane of the body 2. The set 37 of actuators comprises a front actuator rod 41 in contact with the most proximal (closest to the plate body 2) tab 224, and a middle actuator rod 42 in contact with the tab 224 of the next clamp 200, and a rear actuator rod 43 in contact with the tab 224 of the distal-most clamp 200. The actuators are individually pressed by having an indentation 41(a), 42(a), and 43(b) respectively in the exposed top surface, allowing each connector opening 33, 34 and 34 to be opened to (a) allow insertion of a braided / stranded wire termination, and / or (b) opening of the connector. These indentations are shaped to be easily pressed by a pointed tool such as a screwdriver.

[0077] If the wire termination is of a solid wire of sufficient strength, then it is simply pushed in without need to use the relevant actuator to open it.In use, the electrician draws the wires from the ceiling and, in necessary, pares away the insulation to the extent indicated by the markings 91 on the top of the dummy terminal 90. The wire terminations are trained through the body 2 opening 25 and are inserted into the relevant connector opening in the wiring interface 26. There may be up to three wire terminations for each of Live, Earth, Interconnect, and Neutral, allowing versatility in the wiring looping arrangements without need to insert multiple terminations into a single connector opening. The connectors are easily accessed due to the slope of the wiring interface 26 being at an acute angle relative to the plane of the aperture 25 (the plane of the body wall which has the aperture). Where the terminations are single conductors, they are simply push-fitted. Where braided, the relevant actuator rod is pressed with a pointed tool to open and allow easy insertion of the termination.

[0078] If the electrician deems it helpful, he / she can unclip the terminal block 20 from the body 1 by release of the terminal clips.

[0079] The cover 300 is put in place on the terminal block, and the body 2 is then secured to the ceiling by screws. The mounting plate 1 is now ready for the alarm device to be slid into position with the spades 1001 being pushed into the sockets 46, 66, 86, and 116, and the required mechanical interlock connections being made between clips of the alarm device and the apertures 6.

[0080] It will be appreciated that the invention allows an installer to fit solid wire directly into the terminals with an automatic clamping action. Fig. 9 shows an example termination T in place in the top opening 35. In the case of stranded wires an individual button of the relevant sets 37, 67, 87, or 107 is used to open the specific clamp 200 prior to inserting the wire. Once the actuator is released the clamp is engaged, securing the wire. The same buttons can be used to quickly remove the wire from the terminal block on the mounting plate.

[0081] Advantageously, the tops of the actuator rods are in the form of buttons in the top of the terminal block 20 each having an indentation allowing for easy pushing of the actuator. Each push fit connector opening has its own dedicated button such as 1(a), 42(a), and 43(a) to open the associated clamp 200. This allows for manipulation of individual wires without affecting others.

[0082] The terminals 30, 50, 70, 90, and 100 are separate and interconnected by the snap-fit ridges 39 / 59 / 79 / 109 and corresponding slots to form the block 20. The number of terminals is variable, allowing for different configurations such as only live and neutral or live, neutral earth and interconnect. Because each terminal comprises multiple push fit wiring connections stackedvertically, they can be connected in parallel. This provides a dedicated connection for each individual wire and avoids multiple wires in the same connector opening, for a safer and more reliable installation. The terminal front surfaces are inclined so that the wire connection points offer good visibility on install.

[0083] Each terminal is colour coded for the appropriate electrical potential. This provides a clear indication to the installer and minimises risk of incorrect wiring. The terminal block 20 is marked with a strip length indicator 91 on top of the dummy terminal 90, which gives visual and physical instruction to the installer for correct wire strip length.

[0084] Each terminal has test probe access from the top (openings 36, 56, 76, 106) which allows for ease of testing when wires are fitted.

[0085] Referring again to Figs. 6 and 7, each conductor assembly has a flat conductor leading to and supporting the relevant socket. In the case of the assembly 150 it is a flat conductor 215, and in the case of the assembly 250 it is a flat conductor 265.

[0086] As shown in Figs. 8 and 9 the terminal 30 plastics body 38 has a narrow channel 49 which receives the length 215 or 265 as applicable of the conductor linking the clamps 200 to the socket 46. The channel 49 and the conductor 215 have a cross-sectional area to present none or almost no space for passage of air through the channel. During manufacture this is side loaded. The terminals 50, 70, and 100 each have a similar arrangement. This internal wall structure of the channel 49 minimises airflow through the terminal block. This is very advantageous for smoke alarm devices, which are very sensitive to airflow from ceiling voids. The wall structure of the plastics housing 38 has only the narrow channels 49 which the current carrier 215 / 265 almost fills from the wiring side to the smoke alarm connection side, thus restricting airflow through the terminal. In one embodiment, additional sealant material can be applied to the channel prior to assembly, thus completely eliminating residual airflow through the channel.

[0087] Accordingly, the terminal block provides no path for air which originates in the ceiling space and would otherwise flow through the aperture 25 and the wiring interface openings through to the device interface. Moreover, as illustrated in Figs. 10 to 14 the cover 300 provides an additional level of sealing, having a resilient seal pressing each surface of the block and the surrounding housing / body surfaces. The cover 300 has a long side wall 301, a short side wall 303 and a top wall 305 which together present an opening 304 around the device interface.As shown particularly in Figs. 11 to 14 there is a black rubber seal 310 around the lower edge of the side walls, and this seal comprises a rubber strip with a base and a protruding ridge. The top wall 305 has a seal 311 running across to engage with the top surface of the block 20 adjacent the device interface. This seal also has a base and a protruding ridge. These seals are best shown in cross section in Fig. 12. Those seals which extend normal to the plane of the plate 2 are best shown in cross section in Fig. 13. There are vertical seals 312 and 313 pressing against side surfaces of the block 20 adjacent the device interface.

[0088] These drawings also show the wiring side end 317 of the cover 300, for physical engagement with the body 2. The end 317 has a snap-fit lug 318 arranged to extend into the body 2 to snap fit behind the latch ledge 15. The cover end 317 also has a tongue 320 arranged to extend into the aperture 16 of the body 2, to assist with lateral location of the cover, thereby ensuring accurate alignment of the seals 210 to 313 with the various rigid surfaces.

[0089] As shown particularly in Fig. 14 the cover 300 is placed in position by a rotating action around the top of the device interface, with an inwardly directed feature 325 engaging underneath a concave feature 17 of the block 20, and an equivalent pair of features on the opposed side of the block’s device interface. In the rotating action the features 325 engage underneath the block features 14 so that the cover 300 presses the seal 311 against the top of the block at the device interface. This action also provides a bias upwardly so that there is an accurate and positive snap fit to the end latch 318 into the body 2, also thereby applying pressure on the seals 31.

[0090] As seen in Fig. 13 any air entering from a ceiling space through the aperture 25 to the right of the block 20 remains within the chamber formed by the cover 300 on the wiring interface side of the block 20. The seals 310 to 313 prevent passage of air around the block 20 and the internal arrangement of the conductors and passageways 49 leading to the device interface also block air which enters any of the openings in the wiring interface 26. This is most clearly shown in Fig. 13, in which air which is present in a cavity such as a ceiling space behind the aperture 25 may flow through the aperture 25 (out of the plane of the page). However, such air is retained in a chamber formed between:

[0091] the walls 301-305 of the cover 300;

[0092] the seals 310-313; and

[0093] internally in the block 20, the passages 49 matching the cross-sectional shapes of the conductors 215 / 265 so that any air which flows into the openings such as 33-35 in thewiring interface 26 do not reach the device interface 22.

[0094] Advantageously, the seals 310-316 form a complete seal against the terminal block 20 and also the plate 2. The features of the cover allow for simple and effective covering of the wiring terminations and prevention of air flow towards the device interface, in a manner which is effective even for wiring in awkward locations. For example. The hinging arrangement allows the real 311 to be in compression and the latching and lateral tongue locating features allow for accurate engagement of all seals with the applicable body and block surfaces.

[0095] The terminal block can be clipped on and off the mounting plate body 2, allowing for wiring of the terminal block before installing the mounting plate. The clip feature (e.g. 31, 32) securely holds the terminal block on the plate and can be released by use of a tool to deflect the longer clip 32 and its equivalent clips on the other terminals 50, 70, 90, and 100. It is envisaged that this may not be necessary on a lot of occasions due to the convenience of the sloped wiring interface 26 and there being multiple connector openings per terminal.

[0096] Components of embodiments can be employed in other embodiments in a manner as would be understood by a person of ordinary skill in the art. The invention is not limited to the embodiments described but may be varied in construction and detail.

Claims

Claims1. A mains-powered device mounting plate (1), the mounting plate comprising:a body (2) with features (4) for affixing to a substrate such as a ceiling,an aperture (25) in the body for training of wires through the body (2), anda terminal block (300) comprising:a plurality of terminals (30, 50, 70, 100) each comprising:a wiring interface with openings (33, 53, 73, 103) to receive terminations of wires that have been trained through said aperture (25) in the body (2), said openings of the terminals providing a wiring interface (26),terminal conductors (150, 250) with wiring connectors (200) aligned with said openings, anda device interface with terminal connectors (46, 66, 86, 116) for electrical engagement with device connectors (1001) in a sliding action, said connectors of the terminals providing the device interface (22).

2. A mounting plate as claimed in claim 1, wherein each terminal comprises a plurality of wiring interface openings (33, 35, 35) and associated wiring connectors (200) so that a plurality of wire terminations of the same potential or signal can be individually engaged in a single terminal (30, 50, 70, 100).

3. A mounting plate as claimed in claim 2, wherein the wiring connectors (200) are shorted together by a unitary conductive support (210, 260) which also supports the device interface terminal connectors (46, 66, 86, 116).

4. A mounting plate as claimed in any preceding claim, wherein the wiring interface (26) has a face with said openings and said face is sloped at an acute angle to a plane of the mounting plate body and / or to a plane of the aperture (25) through which the wire terminations are trained.

5. A mounting plate as claimed in claim 4, wherein at least some of said terminals each has a staggered arrangement of wiring interface connectors (200), and they are preferably equidistant from a front surface of the terminal interface.

6. A mounting plate as claimed in any preceding claim, wherein at least some of the wiring interface connectors comprises a clamp (200) with a sloped leaf spring (223) to allow push engagement of a wire termination with stiffness of a single wire.

7. A mounting plate as claimed in any preceding claim, wherein at least some of the connectors have a leaf spring (221, 222, 223) for a normally closed position.

8. A mounting plate as claimed in claim 7, wherein at least some of the terminals each comprises an actuator rod (41, 42, 43) each associated individually with a connector (200) to individually release a single connector (200) by way of a pressing action of the actuator rod against the connector.

9. A mounting plate as claimed in claim 8, wherein at least some wiring interface connectors comprises a tab (224) linked with the leaf spring so that pressing of the tab causes a leaf spring contactor (223) to release.

10. A mounting plate as claimed in claim 9, wherein the tab (224) is laterally of the leaf spring contactor (223).

11. A mounting plate as claimed in any of claims 8 to 10, wherein at least some actuators each comprises an exposed button with an indentation (41(a), 42(a), 43(a)).

12. A mounting plate as claimed in claim 11, wherein the button is in a top surface of the terminal.

13. A mounting plate as claimed in any preceding claim, wherein the terminal block includes a dummy terminal (90) which is insulating and is mounted between two terminals to provide additional insulation between said terminals.

14. A mounting plate as claimed in claim 13, wherein the dummy terminal (90) has indicia (91) in a top surface to provide guidance for an installer.

15. A mounting plate as claimed in claim 14, wherein said indicia comprises a length indicator (91) for indicating in a direction aligned between the wiring interface (26) and the device interface (22) a distance for exposure of wire at a termination.

16. A mounting plate as claimed in any preceding claim, wherein the terminal block comprises clips (31, 32) for releasable engagement with the plate body (2).

17. A mounting plate as claimed in claim 16, wherein the terminals are separable and each has at least one clip for releasable engagement with the plate body (2) and features (39, 59, 57, 109) for releasable engagement with each other.

18. A mounting plate as claimed in claim 17, wherein the features include protrusions such as ribs (39) for snap-fitting into corresponding recesses such as grooves of adjoining terminal housings.

19. A mounting plate as claimed in any preceding claim, wherein at least one terminal comprises a channel (49) housing a conductor support (215, 265) for a device interface terminal connector (46).

20. A mounting plate as claimed in claim 19, wherein the channel and the conductor have matching cross-sectional areas to restrict or block passage of air through the channel.

21. A mounting plate as claimed in any preceding claim, further comprising a cover having a top wall (305) and side walls (301-304) configured to surround the terminal block and said aperture (25) in the body, and to seal against the block and the body.

22. A mounting plate as claimed in claim 21, wherein the cover comprises a plurality of resilient seals (310-313) anchored in the cover walls and configured to press against external surfaces of the terminal block (20) and surfaces of said body (2).

23. A mounting plate as claimed in claim 22, wherein the seals are arranged to engage across a top surface of the block and side walls of the block so that the cover forms a seal around the block to prevent air from the aperture (25) from flowing around the block towards the device interface.

24. A mounting plate as claimed in claim 23 when dependent on claim 20, wherein said channels (49) and said cover seals provide a sealed chamber around the body aperture (25).

25. A mounting plate as claimed in any of claims 22 to 24, wherein at least some of said seals (310-313) each comprises a base anchored in a cover wall and a protruding elongate ridge.

26. A mounting plate as claimed in any of claims 22 to 25, wherein the cover is configured to engage the block adjacent the device interface in a pivoting action with at least one block feature (17) retaining a cover feature (325, 326) so that the cover presses a seal (311) against the block across the device interface.

27. A mounting plate as claimed in any of claims 22 to 26, wherein the cover and the body (2) have inter-engaging snap fit fasteners (318, 150) for snap fitting at an end (317) of the cover closest to the wiring interface.

28. A mounting plate as claimed in any of claims 22 to 27, wherein the cover comprises a tongue (320) arranged to fit in an aperture (12) of the body adjacent a snap-fit fastener to assist accurate location of the cover for seal engagement.

29. An alarm device assembly comprising a mounting plate (1) of any preceding claim and an alarm device configured to be physically and electrically (1000) mounted to the mounting plate.

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