GB2056179A - The mounting of circuit breakers - Google Patents

Abstract

An array of circuit breakers are mounted on an assembly, comprising a mounting rail (20) with a mounting flange (28). For engagement by a catch assembly 16 on the circuit breaker when attached to a bus bar (42) the mounting rail (20) having stabilising means (32) which, are engaged by the catch assembly 164 to restrain movement of the circuit breaker relative to the mounting rail (20) in a direction longitudinally of the mounting rail. In modifications the outer ends 18 of the spring catch may engage over or between projections of the rail 20 extending beyond the circuit breaker wall or may engage the edge of the rail frictionally. <IMAGE>

Description

SPECIFICATION Improvements relating to the mounting of circuit breakers This invention is concerned with improvements relating to the mounting of circuit breakers.

A conventional circuit breaker (herinafter referred to as a circuit breaker of the kind specified) is provided on an underside thereof with a mounting recess bounded at one side edge portion by an inwardly-turned lip, providing a fixed re-entrant surface, an opposite side edge portion of the recess being bounded by a straight side ege. The circuit breaker comprises a catch assembly, urged by a spring from a retracted position to an advanced position, in which advanced position a wedge-shaped retaining element of the catch assembly projects a short distance into the recess.In such a circuit breaker, the retaining element may be on the same side of a medial plane of the circuit breaker as the connector by which external wiring is connected thereto, in which case the fixed re-entrant surface will be on the same side of the medial plane as the bus-bar by which the circuit breaker is connected to a suppiy of electricity.

Conventionally, circuit breakers of the kind specified are mounted on a mounting rail conventionally termed a "Din-rail", which comprises parallel upwardly facing flanges provided with narrow out-turned lips. The reentrant surface is engaged beneath one of the lips with the underside of the circuit breaker inclined relative to the rail, and the circuit breaker is moved angularly so as to cause the retaining element to engage the other lip, the profile of the retaining element causing it to be momentarily depressed as it passes behind the other lip. The circuit breaker is then clamped to a conventional bus-bar, supported in parallel relation to the rail.

When it is required to remove one circuit breaker from an array of circuit breakers from the rail, the retaining element is manually retracted, and the circuit breaker is tilted to permit lateral movement of the circuit breaker relative to the rail to disengage the fixed re-entrant surface from the rail. This necessitates the temporary removal of the bus-bar, and this is inconvenient since it involves disruption of the connections of all the other circuit breakers and of the isolator with the bus-bar.

In the Specification of U.K. Patent application No. 2007434A, there is described a mounting rail on which an array of circuit breakers of the kind specified may be mounted, the rail comprising a single flange extending the full operative length of the rail and which is provided with a single out-turned lip extending along the side of the mounting rail opposite to that side on which the bus-bar is provided. Conventional circuit breakers may be mounted on the mounting rail by firstiy, engaging the retaining element beneath said lip, and resting the opposite underside of the circuit breaker against a flat base surface of the rail. The connector of the circuit breaker may be secured to the bus-bar, providing for a two point connection of the circuit breaker to the mounting assembly.

When it is desired to remove one of the circuit breakers from the mounting assembly, it is merely necessary to loosen the connector from the busbar and to withdraw the circuit breaker laterally away from the bus-bar, and this may be effected without disturbance to adjacent circuit breakers or the bus-bar. Similarly, a replacement circuit breaker may be mounted on the mounting rail, between existing circuit breakers, without disturbance to such adjacent circuit breakers or their connections with the bus-bar.

It has now been appreciated that, in certain circumstances, it is desirable to provide additional support for the circuit breaker, such as will be effective to restrain movement thereof, notwithstanding its connection to the bus-bar, on the side thereof opposite to the bus-bar, and it is one of the various objects of the invention to provide a mounting assembly for a circuit breaker of the kind specified, which provides additional restraint to movement of the circuit breaker relative to the mounting rail.

According to this invention there is provided a mounting assembly for an array of circuit breakers of the kind specified, the mounting assembly comprising (a) a mounting rail comprising a base plate and a mounting flange extending from the base plate; and (b) a bus-bar extending in spaced relationship from the base plate parallel to the longitudinal axis of the mounting rail on the side thereof opposite the mounting flange, the construction and arrangement being such that, in the use of the mounting assembly, a plurality of circuit breakers of the kind specified may be seated on the base plate in engagement with the mounting flange and connected to the bus bar, wherein the mounting rail comprises stabilising which, when such a circuit breaker is mounted thereon, is engaged by the catch assembly of the circuit breaker, such engagement being operative to restrain movement of the circuit breaker relative to the mounting rail in a direction longitudinally of the mounting rail.

Preferably the engagement between the stabilising means and the catch assembly is also operative to restrain lifting movement of the circuit breaker away from the base plate.

Retraction of the catch assembly from its advanced position may cause the catch assembly to disengage from the stabilising means, whereupon such relative movement may readily be effected.

It is within the scope of this invention, that frictional engagement between the catch assembly of the circuit breaker and the stabilising means is operative to restrain such relative longitudinal movement, and/or such lifting movement.

The construction and arrangement of the mounting assembly may be such that said engagement between the catch assembly of the circuit breaker and said stabilising means permits substantially linear separative movement of the circuit breaker from the mounting assembly in a direction at right angles to the longitudinal axis of the rail.

Said linear separative movement of the circuit breaker from the mounting assembly in said directions at right angles to the longitudinal axis of the mounting rail may be preceded by limited lifting movement of the circuit breaker away from the catch plate. If desired said limited lifting movement of the circuit beaker may be permitted by movement of the catch assembly to its retracted position, and disengagement thereof from said stabilising means.

Preferably the mounting rail is provided with a plurality of locating tabs extending on the side of the mounting rail opposite to the bus-bar, said locating tabs being adapted to be engaged by the circuit breakers and affording the stabilising means of the mounting rail. The locating tabs may be arranged to be engaged by a forward, inner portion of the catch assembly, or by a rearward, outer portion of the catch assembly.

Restraint to movement of a circuit breaker mounted on the mounting assembly relative to the mounting rail in a direction longitudinally of the mounting rail may be afforded by longitudinal abutment between a portion of the catch assembly and at least one of the locating tabs, conveniently engagement between the catch assembly when in its advanced position and the locating tab being operative to restrain lifting movement of the circuit breaker away from the base plate.

Alternatively the stabilising means may be provided by a lip extending lengthwise of the mounting rail on the side thereof opposite to the bus-bar, which when the catch assembly is in its advanced position is engaged on a rearward, outer side by a portion of the catch assembly, to restrain lifting movement of the circuit breaker away from the base plate, frictional engagement between said portion of the catch assembly and the lip restraining movement of the circuit breaker relative to the mounting rail in a direction longitudinally of the mounting rail.

There.will now be given a detailed description, to be read with reference to the accompanying drawings, of various embodiments of this invention which have been selected to illustrate the invention by way of example.

In the accompanying drawings.

FIGURE 1 is a side elevation of a conventional circuit breaker, being a circuit breaker of the kind specified; FIGURE 2 is a plan view of the mounting rail of a mounting assembly which is a first embodiment of the invention; FIGURE 3 is a side elevational view, showing the mounting rail illustrated in Figure 1 mounted on two support brackets; FIGURE 4 is a plan view of the mounting assembly of the first embodiment, showing a conventional isolator mounted on the mounting assembly, and indicating the positions adopted by the mounting thereon of circuit breakers of the kind illustrated in Figure 1; FIGURES 5, 6 and 7 are enlarged views illustrating the engagement between part of a catch assembly of the circuit breaker with a retaining flange of the mounting rail of the first embodiment;; FIGURES 8 and 9 are views corresponding to Figures 2 and 3, of the mounting rail of a mounting assembly which is a second embodiment of this invention; FIGURE 10 is an enlarged view of part of a retaining flange of the mounting rail of the second embodiment of this invention.

FIGURES 11 and 12 are views corresponding to Figures 5 and 6, illustrating the engagement between the catch assembly of the circuit breaker and the retaining flange of a mounting assembly which is the second embodiment of this invention; FIGURES 13 and 14 are views, corresponding to Figures 11 and 12, illustrating engagement between the catch assembly of the circuit breaker and the retaining flange of a mounting assembly which is the third embodiment of this invention, and FIGURES 1 5 and 1 6 are views corresponding to Figures 11 and 12,illustrating the engagement between the catch assembly of the circuit breaker and the retaining flange of a mounting assembly which is the fourth embodiment of this invention.

Figure 1 illustrates a conventional circuit breaker, in particular a circuit breaker of the kind specified which is provided on an underside thereof with a mounting recess 6.

One side edge of the recess is bounded by an inwardly-protruding lip 8, which provides a fixed re-entrant surface 10, and an opposite side edge 11 of the recess is straight-edged.

The circuit breaker is provided with a springloaded catch assembly 12, comprising a catch plate 14 urged into an advanced position, in which wedge-shaped retaining elements 1 6 extend through the side edge 11; by a spring 1 5 (Figure 6).

The mounting assembly which is the first embodiment of this invention comprises a mounting rail 20 which comprises a base plate 22, provided with a down-turned lip 23 at one side edge. At one end of the base plate 22 the mounting rail is provided with parallel flanges 24,24, provided with outwardly-turned lip portions 26,26 (see also Figure 2). It is to be noted that the flanges 24 extend lengthwise of the mounting rail 20 for only a short distance from said one end, and provide means to facilitate the mounting of one or more isolators, as will hereinafter be described.

For the rest of the length of the mounting rail, on the side thereof opposite to that on which the lip 23 is provided, the mounting rail comprises a mounting flange 28, comprising a curved section 30, and stabilising means afforded by a plurality of locating tabs 32, positioned at spaced intervals along the length of the rail 20, the spacing of said locating tabs being equal to the width of the circuit breaker (as shown in Figure 4).

The mounting assembly which is the preferred embodiment of this invention also comprises a pair of support brackets 36, 36, on which the rail 20 is mounted, one of said support brackets 36 being locted adjacent to a support post 38.

A conventional isolator 40 is mounted on the mounting rail, in particular being located over and around the flanges 24 and the out-turned lips 26 thereof, and a bus-bar 42 is connected between the isolator 40 and the support post 38.

To mount a circuit breaker of the kind illustrated in Figure 1 on the mounting raii of the first embodiment of this invention, the flat surface 5 of the circuit breaker is placed on the base plate 22 with the mounting flange 28 located within the recess 6, and the circuit breaker is moved in the direction of the arrow 'A' transversely of the mounting rail towards the bus-bar 42 (Figure 4).

As the connector screw 9 of the circuit breaker moves into one of the apertures of the bus-bar 42, the leading end of the catch assembly 12 moves into engagement with the mounting flange 28.

The tapered section of the locating tab tends to centralise the circuit breaker, and the locating tab passes beneath the pair of retaining elements 16, and over a base portion 1 7 of the catch plate 14 (Figures 5 and 6). Since the retaining elements 16 engage the curved section 30 of the retaining flange, the spring 1 5 is additionally effective to urge the base portion 17 into engagement with the locating tab 32.

It will however be appreciated that the strength of the spring 1 5 must not be sufficient to cause, by virtue of the engagement between the retaining elements 1 6 and the curved section 30, any significant force of the circuit breaker in the direction away from the bus-bar 42, and may be dispensed with. Alternatively, the curved section 30 may be afforded with notches 1 6a on either side of the tabs 32, into which the retaining elements extend, when the catch plate 14, is in its advanced position. The position of such notches 1 6a is shown in dotted lines in Figure 5.

Such engagement between the catch assembly 12 and the retaining flange is effective to prevent movement of the circuit breaker in the direction 'D' Figure 5, which is movement of the circuit breaker relative to the mounting rail in a direction longitudinally of the mounting rail, by virtue of the engagement of the retaining element 16 on opposite sides of the locating tab 32. Such engagement is also effective to prevent movement of the circuit breaker in the direction 'C', Figure 6, which is lifting movement of the circuit breaker away from the base plate, by virtue of the engagement of the base portion 1 7 beneath the locating tabs 32.Additionally, movement of the circuit breaker from the mounting rail in a direction at right angles to the longitudinal axis of the mounting rail (B) is restrained by frictional engagement between the locating tab 32 and the base portion 1 7 of the catch plate 14.

Removal of the circuit breaker from the mounting assembly which is the first embodiment of this invention may be effected simply, by loosening of the connecting screw 9, and movement of the circuit breaker in the direction 'B'. Such movement may be effected within a vertical plane containing the circuit breaker, that is without disturbance to adjacent circuit breakers mounted on the rail 20. Such movement of the circuit breaker may be rendered slightly more easy, by a small retraction of the catch plate 14 against the force of the spring 1 5, but this is not necessary.

The mounting assembly which is the second embodiment of this invention (see Figures 8 to 12) is similar in certain circumstances to that which is the first embodiment, and similar numerals with the suffix a will be utilised in relation to parts similar to those present on the first embodiment.

Thus, the mounting rail of the second embodiment comprises a base plate 22a, a down-turned lip 23a and flanges 24a having out-turned portions 26a for the mounting of a conventional isolator.

However, in the second embodiment, the mounting rail is provided with a continudus mounting flange 128, which provides a continuous shoulder 129 extending over that side edge of the mounting rail on which the retairiing flanges 26a is not provided. Additionally, at spaced intervals along the said length of the mounting rail, the retaining flange 128 is provided with stabilising means afforded by a number of hook-shaped locating tabs 132. In the mounting of a circuit breaker of the kind specified on the mounting rail illustrated in Figure 8, the circuit breaker is moved towards the bus-bar generally in the direction of the arrow 'A' but inclined slightly to the base plate 22a.As the connecting screw 9 passes into one of the slots of the bus-bar, the circuit breaker is depressed into flat abutment with the base plate 22, the locating tab 132 passing through the aperture 19 in the tail portion of the catch assembly 12.

Movement of the circuit breaker relative to the mounting rail 20a transversely away from the busbar (direction B) is prevented by engagement of a corner portion of the circuit breaker with the shoulder 129 of the retaining flange 128 (see Figure 1 2). Lifting movement of the circuit breaker away from the mounting rail (direction C) is prevented by engagement of the tail portion 1 8 of the catch assembly 12 with the locating tab 1 32 (again see Figure 12), it being appreciated that the tail portion 1 8 is in this position moved into engagement with the locating tab 132 by the spring 15.

Additionally, movement of the circuit breaker longitudinally of the mounting rail in the direction 'D' (Figure 11) is prevented by engagement of the locating tab 1 32 between the sides of the catch plate 14 bounding the slot 19.

In order to remove the circuit breaker from the mounting rail, the tail portion 18 may be manually retracted, assisted if necessary by the use of a screwdriver, to an extent which permits movement of the locating tab 132 through the slot 19, until the base of the circuit breaker clears the shoulder 129. The circuit breaker may then be moved generally linearly, in the direction 'B' away from the bus-bar 42 subsequent to the releasing of the connecting screw 9.

It will be appreciated that, whereas in the second embodiment, the positioning of the locating tabs 132 is such that adjacent locating tabs 132 may be positioned within the slots 1 9 of adjacent circuit breakers, in the embodiment illusrated in Figures 13 and 14, a variation in the construction and positioning of the locating tabs (indicated in Figures 13 and 14 by the numeral 232) is effected. Thus, as is illustrated in Figure 1 3, in the third embodiment of this invention the mounting rail is provided with locating tabs, each of which engage part of the tail portion 1 8b of each of a pair of adjacent circuit breakers.

Engagement between these locating tabs 232 and the catch assembly 1 2b of the circuit breaker similarly restrain lifting movement of the circuit breaker, and movement longitudinally of the mounting rail, lateral separation of the circuit breaker being prevented, as in the second embodiment, by the provision of a continuous shoulder 229.

In the mounting assembly which is the fourth embodiment of this invention (illustrated in Figures 1 5 and 16) the mounting flange 28c is provided, not only with a continuous shoulder 329, but also with a continuous downturned lip 330.

The mounting rail of the fourth embodiment is specifically for use in conjunction with a circuit breaker, the tail portion 1 8c of the catch plate 1 4c of which is modified, in the provision of a downwardly and inwardly turned lip 320.

Engagement between the lip 320 of the catch assembly of the circuit breaker with the lip 330 of the mounting rail, when the circuit breaker is mounted on the mounting rail, is effective to prevent movement of the circuit breaker, in the direction indicated by the arrow 'C' in Figure 1 6.

Additionally, movement of the circuit breaker in the direction 'B' is restrained by engagement of the circuit breaker with the shoulder 329 of the retaining flange, whilst movement of the circuit breaker relative to the mounting rail in a direction longitudinally of the mounting rail (direction D) is restrained by frictional engagement between the lip 320 of the catch assembly with the lip 330 of the mounting rail.

To release the circuit breaker from the mounting rail which is the fourth embodiment of this invention, subsequent to release of the connecting screw, the tail portion 1 8c of the catch assembly may be manually retracted (for example by the insertion of a screw driver through the slot 1 9c and by a prising action against the lip portion 330) to separate the lip portions 320 and 330 to allow limited movement of the circuit breaker in the direction 'C'. Subsequent to clearance by the circuit breaker of the shoulder 329, the circuit breaker may be moved in the direction 'B' away from the mounting rail.

In both the third and fourth embodiments, illustrated in Figures 13 and 14, and 1 5 and 16, respectively, the tail portion of the catch plate is provided with an upwardly-turned lip. 1 8b' and 18cm, respectively. By this means, a tool such as a screwdriver may be inserted between this lip and the sloping back face of the circuit breaker, and the catdh plate 14 as a whole may be moved rearwardly, against the action of the spring, to - disengage the tail portion 18 of the catch assembly from the tab 1 32. With such movement accomplished, the circuit breaker may be moved in the direction of the arrow C, clear of the shoulder 229, 329 respectively.

Claims (20)

1. A mounting assembly for an array of circuit breakers of the kind specified, the mounting assembly comprising (a) a mounting rail comprising a base plate and a mounting flange extending from the base plate; and (b) a bus-bar extending in spaced relationship from the base plate parallel to the longitudinal axis of the mounting rail on the side thereof opposite the mounting flange, the construction and arrangement being such that, in the use of the mounting assembly, a plurality of circuit breakers of the kind specified may be seated on the base plate in engagement with the mounting flange and connected to the bus bar, wherein the mounting rail comprises stabilising means which, when such a circuit breaker is mounted thereon, is engaged by the catch assembly of the circuit breaker, such engagement being operative to restrain movement of the circuit breaker relative to the mounting rail in a direction longitudinally of the mounting rail.

2. A mounting assembly according to Claim 1 wherein the engagement between the stabilising means and the catch assembly is also operative to restrain lifting movement of the circuit breaker away from the base plate.

3. A mounting assembly according to any one of Claims 1 or 2 wherein retraction of the catch assembly from its advanced position causes the catch assembly to disengage from the stabilising means, whereupon such relative movement may readily be effected.

4. A mounting assembly according to any one of the preceding claims wherein said engagement by the catch assembly of the circuit breaker with the stabilising means is operative to provide frictional restraint to such relative longitudinal movement, and/or such lifting movement.

5. A mounting assembly according to any one of Claims 1,2 and 3 wherein the construction and arrangement is such that said engagement between the catch assembly and the stabilising means permits substantially linear separative movement of the circuit breaker from the mounting assembly in a direction at right angles to the longitudinal axis of the mounting rail.

6. A mounting assembly according to any one of the preceding Claims wherein such linear separative movement is preceded by limited lifting movement of the circuit breaker away from the base plate.

7. A mounting assembly according to Claim 6 wherein said limited lifting movement is permitted by movement of the catch assembly to its retracted position and disengagement thereof from the stabilising means.

8. A mounting assembly according to Claim 1 wherein the mounting rail is provided with a plurality of locating tabs extending on the side of the mounting rail opposite to the bus-bar, said locating tabs being adapted to be engaged by the circuit breakers and affording the stabilising means of the mounting rail.

9. A mounting assembly according to Claim 8 wherein said locating tabs are engaged by a forward, inner portion of the catch assembly.

10. A mounting assembly according to Claim 8 wherein said locating tabs are engaged by a rearward, outer portion of the catch assembly.

11. A mounting assembly according to Claim 8, 9 and 10 wherein restraint to movement of a circuit breaker mounted on the mounting assembly relative to the mounting rail in a direction longitudinally of the mounting rail is afforded by longitudinal abutment between a portion of the catch assembly and at least one of the locating tabs.

12. A mounting assembly according to Claim 11 wherein when the catch assembly is in its advanced position, it engages beneath the locating tab, such engagement being operative to restrain lifting movement of the circuit breaker away from the base plate.

1 3. A mounting assembly according to any one of Claims 8 to 1 2 wherein said locating tabs are each associated with a circuit breaker individually.

14. A mounting assembly according to any one of Claims 8 to 12 wherein said locating tabs are each associated with a pair of adjacent circuit breakers.

1 5. A mounting assembly according to any one of Claims 8 to 14 wherein the mounting rail is provided with a shoulder which is engaged by the circuit breaker when in position on the mounting rail, such engagement being operative to restrain linear separative movement of the circuit breaker relative to the mounting rail in a direction at right angles to the longitudinal axis of the rail.

1 6. A mounting assembly according to Claim 1 wherein said stabilising means is provided by a lip extending lengthwise of the mounting rail on the side thereof opposite to the bus-bar, which when the catch assembly is in its advance position is engaged on a rearward, outer side by a portion of the catch assembly, to restrain lifting movement of the circuit breaker away from the base plate, frictional engagement between said portion of the catch assembly and the lip restraining movement of the circuit breaker relative to the mounting rail in a direction longitudinally of the mounting rail.

1 7. A mounting assembly according to any one of Claims 8 to 1 5 wherein on movement of the catch assembly to its retracted position, the catch assembly is disengaged from the stabilising means and the circuit breaker is permitted to be moved away from the mounting rail.

18. A mounting assembly according to any one of the preceding claims, wherein the mounting rail is provided with means to facilitate the mounting of one or more isolators thereon.

1 9. A mounting assembly for an array of circuit breakers of the kind specified constructed and arranged substantially as hereinbefore described, with reference (a) to Figures 2 to 7, (b) to Figures 9 to 12, (c) to Figures 13 and 14, or (d) to Figures 15 and 16.

20. Any novel feature or combination of novel features hereinbefore described and/or illustrated in the accompanying drawings.