GB2077040A

GB2077040A - Mounting assembly for electrical devices

Info

Publication number: GB2077040A
Application number: GB8016961A
Authority: GB
Original assignee: Midland Electric Manufacturing Co Ltd
Current assignee: Midland Electric Manufacturing Co Ltd
Priority date: 1980-05-22
Filing date: 1980-05-22
Publication date: 1981-12-09
Also published as: GB2077040B

Abstract

Mounting means for electrical devices (24) designed for DIN-rail mounting and having a recessed mounting face and catch means within the recess, consist of an assembly of: a pair of spaced side- bars (12, 13) each having a thickness greater than the depth of the U-shaped recess (25) of a device; a bus-bar (14) secured to feet (12A, 13A) of the side bars; and an L- section catch plate (17) secured to the side bars to enclose shoulders (16) formed on the side bars. The catch plate (17) has a free edge (20) extending away from the bus- bar (14). Each electrical device 24 is mounted with its catch (26) sprung behind the edge (20) and with its terminal screw (30) secured in a slot (21) of the bus-bar (14). To locate the device (24) properly relative to the catch plate (17), key- hole slots (21) are adopted. <IMAGE>

Description

SPECIFICATION Mounting means for electrical device This invention relates to mounting means for electrical devices each of the type having a mounting face with a shallow U-shaped recess therein, adapted to receive a rail of the type described in German Standard DIN 46277 Sheet 3, and with catch means projecting into the' recess to engage with an edge of the DINrail and electrical connection means at opposite ends. An example of such an electrical device, which will be referred to hereinafter as "an electrical device of the type described" is a miniature circuit breaker (MCB).

It is frequently necessary to mount a number of such electrical devices together for connection to a common bus-bar, in the case of a single-phase supply, or to a number of bus-bars, in the case of a polyphase supply.

Thus, in a domestic distribution system, it is known to clip a number of MCB's to a DIN rail and thereafter to connect them to a busbar or bus-bars. In this known arrangement, the bus-bar or bars can be connected only when all the MCB's are in place on the DIN rail and, in order to remove one of the MCB's it is necessary to disconnect and dismantle the bus-bar or bars.

In our British patent application No.

7940800, we have described mounting means, other than a DIN rail, for so mounting the electrical devices that each can be attached and removed independently, with the bus-bar or bus-bars in situ. The present invention provides alternative, and simplified, mounting means for that purpose.

According to the present invention, mounting means for a plurality of electrical devices of the type described comprises an assembly of two spaced side bars connected together by cross-members, at least one of which is formed as, or with, connection means for the electrical devices, and another, or the other, of which is formed as a catch plate to be engaged by the catch means of one or more of the electrical devices, which is or are then solely held by attachment to the cross-members.

Preferably, the side bars are made up of insulating material and said one cross-member is a bus-bar or bus-bars to which the electrical devices are connectable.

There may be a third cross-member parallel to the other two and spaced from the catch plates, so that a foot of an electrical device be received between the catch plate and the further cross-member, properly to locate the electrical device.

The invention will be for more readily undersood by way example from the following description of single-phase mounting means for electrical devices, reference being made to the accompanying drawings, in which Figure 1 shows in perspective the mounting means with an MCB mounted thereon.

Figure 2 is a side view of the MCB, in relation to the bus-bar and catch plate, and Figure 3 is a plan view of a single phase bus-bar. The mounting means comprise two side bars 1 2 and 13, which are parallel and spaced apart, and which are made of an insulating material, such as a suitable synthetic resin. As shown, each side bar has at one end an integral foot 12A, 1 3A extending at right angles to the length of the side bar; a single-phase bus-bar 14 is secured by means of bolts 1 5 to the feet 1 2a 13a. At the other end of each bar 12, 13, the section is increased to form a shoulder 1 6 and a catch plate 1 7 of L-section is attached to the side bars 12 and 13 by means of bolts 18 to enclose the shoulders 16.The catch plate 1 7 is parallel to the bus-bar 1 4 and has a free edge 20 directed away from the bus-bar.

Single phase bus-bar 14 is formed with a number of key-hole slots 21, shown in greater detail in Fig. 3. Each slot 21 opens to the edge 22 of the bus-bar facing the catch plate 1 7 and widens to a part-circular hole 23.

Any electrical device to be mounted, and particularly the MCB illustrated at 24, has a shallow U-shaped recess 25 in its mounting face, that recess being adapted to receive a DIN rail, although in the present arrangement such a rail is not used. A spring-loaded catch 26 is carried by the structure of the electrical device and is biased into the recess 25 as shown; it may be withdrawn against the spring-loading by operation of a connected finger 27 (Fig. 1). In addition, each end of the electrical device has a terminal, one of which is shown in Fig. 1 at 28, and the other of which is shown in Fig. 2 as consisting of a bolt 30 having a tapered head which is recieved in any of the holes 23.

To mount an electrical device on the mounting assembly formed by the side bars 12, 13, the bus-bar 1 4 and the catch plate 17, the mounting bolt 30 is loosened and the electrical device is seated with the catch plate 1 7 within the recess 25. The mounting bolt 30 is entered into slot 21 and the screw 30 is tightened; because of the relative dimensions of the countersunk portion of the screw 30 and the slot 21, the tightening action has the effect of centering the screw in the partcircular hole 23 and thus locating the electrical device accurately relative to the bus-bar.

The spacing of the bus-bar 1 4 and the catch plate 1 7 is such that, on proper location of electrical device relative to the bus-bar 14, the edge 20 of the catch plate 1 7 is properly located behind the catch 26, so ensuring proper mounting of the electrical device on the mounting framework.

While the key-hole slots 21 ensure proper positioning of the electrical devices, the assembly may further include a further cross member 31 which has an L-section and which is secured at the end of each side bar 12, 1 3 distant from the bus-bar 1 4. Cross member 31 thus has a free edge 32 directed towards the catch plate 1 7 and the spacing of catch plate 17 and cross member 31 corresponds to the length of foot 33 of the electrical device.

As before, the electrical device is placed in position with the loosened screw 30 in a slot 21 and the foot 33 then placed between the wedges 20 and 32, with the catch 26 in its withdrawn position. The cross-member 31 thus ensures the correct positioning of the electrical device and the need for slots 21 of keyhole form and special screws 30 no longer obtains.

It will be appreciated that it is not essential that the side member 12, 1 3 should be of insulating material. However, if they are made of metal, bus-bar 14 must be insulated from them, for example by replacing the integral feet 12A, 1 3A by separate feet. It will be further understood that the mounting assembly is normally located within a switch box, as by attaching the mounting framework to the base of the box by means of bolts (not shown) passing through holes 35 in the side bars 12 and 13.

Figs. 1 to 3 illustrate a single phase installation with a single bus-bar 14. For a multiphase system, bus-bar 14 is replaced by an assembly including a number of bus-bars and connections from those bus-bars terminating at a common level for attachment to individual electrical devices in a manner analogous to that illustrated in the drawings.

Claims

1. Mounting means for a plurality of electrical devices of the type described comprising an assembly of two spaced side bars connected together by substantially parallel crossmembers, at least one of which is formed as, or with, attachment means for the electrical devices, and another, or the other, of which is formed as a catch plate having a free edge facing away from said one cross-member to be engaged by the catch means of the electrical devices, the spacing between the free edge and said one cross-member corresponding approximately to the separation of the catch means of an electrical device from its more distant connection means, so that each electrical device can be solely held by attachment to the cross-members.

2. Mounting means for a plurality of electrical devices of the type described comprising two spaced independent side bars; at least one bus-bar secured between the side bars having, or provided with, attachment means for the electrical devices; and a catch plate which is secured between the side bars and which is in the form of a strip lying on the outer faces of the side bars with a free edge substantially parallel to, and facing away from, the bus-bar or bus-bars; the spacing between that free edge and the attachment means corresponding approximately to the separation of the catch means of an electrical device from its distant connection means, so that each electrical device can be solely held by attachment to the catch plate and the attachment means.

3. The combination of a plurality of electrical devices of the type described and mounting means therefor, the mounting means comprising two spaced independent side bars; at least one bus-bar secured between the side bars having, or provided with, attachment means for the electrical devices; and a catch plate which is secured between the side bars and which is in the form of a strip lying on the outer faces of the side bars with a free edge substantially parallel to, and facing away from, the bus-bar or bus-bars; the spacing between that free edge and the attachment means corresponding approximately to the separation of the catch means of an electrical device from its distant connection means; the arrangement being such that each electrical device is secured with the catch plate recieved in its U-shaped recess by the location of its catch means behind the free end and the securement of its connection means to the attachment means of the busbar or bus-bars.

4. The combination according to claim 3, in which each side bar has a thickness greater than the depth of the shallow U-shaped recess of each electrical device.

5. The combination according to claim 3 or claim 4, in which each side bar is formed with an increased thickness to form a shoulder, and the catch plate has an L-section enclosing each shoulder.

6. The combination according to any one of claims 3 to 5, in which the side bars are bridged by a cross-member located on the side of the catch plate distant from the busbar and spaced from the catch plate by a distance approximating to the length of the foot of each electrical device, so that each electrical device is positioned by its foot being recieved between the edge of the catch plate and the cross-member.

7. The combination according to claim 6, in which the cross-member has an L-section.

8. The combination according to any one of claims 3 to 7, in which the attachment means of the bus-bar or each bus-bar includes a series of key-hole slots which recieve counter-sunk screws of the connection means of the electrical device so as to position the electrical devices properly with respect to the catch plate.

9. Mounting means for a plurality of electrical devices of the type described, which mounting means are substantially as herein described with reference to the accompanying drawings.

10. The combination of a plurality of elec- trical devices of the type described and mounting means therefor, substantially as herein described with reference to the accornpanying drawings.