GB2270210A

GB2270210A - Busway/tap-off box connection with a safety shutter system

Info

Publication number: GB2270210A
Application number: GB9218226A
Authority: GB
Inventors: Andrew Jamie Reynolds; Keith Wray Ball; Andrew Purdie Baker
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1992-08-27
Filing date: 1992-08-27
Publication date: 1994-03-02
Anticipated expiration: 2012-08-27
Also published as: HK1007837A1; GB2270210B; GB9218226D0

Abstract

Electrical connection means comprising a busway tap-off entry (11), to facilitate connection and disconnection of a tap-off box thereat. The entry (11) includes a manually openable slidable cover (15) normally locked in its closed position and locking means (18) arranged to be disengaged upon mechanical location of a tap-off box onto the top of the busway (10) above the entry (11) to enable manual opening of the slidable cover (15) and electrical connection of the tap-off box with the busway tap-off entry (11). The locking means may comprise a spring loaded release mechanism (18) having a levered catch (19b) normally spring urged into engagement with the slidable cover (15) when in its locked and closed position. An attached lever arm (19) is provided for engagement mechanically by a tap-off box to cause disengagement of said levered catch (19b) from the slidable cover (15). <IMAGE>

Description

IMPROVEMENTS IN AND RELATING TO ELECTRICAL CONNECTORS The invention relates to electrical connectors and more particularly to electrical connection means to facilitate the safe electrical connection of a tap-off box to and from a busway tap-off entry ahd to ensure that such busway tap-off entry is securely closed when not in use.

Various safety closures are known for preventing accidental electrical connection to sockets which may result in an electric shock being received by a user, for example, normal household mains sockets are usually shuttered, with automatic opening by the earth pin of a plug to be inserted therein and with tap-off entry points for busbars, operating in a range of up to 800 amperes, so called "finger safe" shielding arrangements may be provided.

However, for providing electrical connection of a tap-off box to and from a busway tap-off entry operating in a range of above 1000 amperes, and for example of 5000 amperes, the electrical contacts are sized of a width greater than that of a finger and require distance of travel of any shuttering which precludes automatic operation.

It is an object of the present invention to obviate or mitigate the above disadvantages.

According to the invention there is provided electrical connection means comprising a busway tap-off entry, to facilitate connection and disconnection of a tap-off box thereat, the entry including a manually operable slidable cover normally locked in its closed position and locking means arranged to be disengaged upon mechanical location of a tap-off box onto the top of the busway above the entry to enable manual opening of the slidable cover and electrical connection of the tap-off box with the busway tap-off entry.

Preferably the locking means comprises a spring loaded release mechanism having a levered catch normally spring urged into engagement with the slidable cover when in its locked and closed position and having an attached lever arm for engagement mechanically by a tap-off box to cause disengagement to said levered catch from the slidable cover.

Furthermore the levered catch may be arranged to engage the slidable cover in its open position to lock it in such open position, further spring means being located to move the slidable cover to its closed position upon movement of the tap-off box, after disengagement of the electrical connection with the busway tap-off entry, by further mechanical connection with said lever arm to disengage the levered catch from engagement with the slidable cover. In this arrangement the further spring means may comprise a pair of extension springs.

The electrical connectors of the busway entry may each comprise male connectors for engagement by corresponding female connectors of the tap-off box, each of said male connectors being located in a separate aperture of the busway entry and having a member or portion of electrically insulating material located over the outer extremity thereof.

The cover may comprise a generally sheet-from member, of electrically insulating material, having handle means integrally formed therewith at one end thereof.

Furthermore the cover may be formed for attachment of safety locking means for locking the cover in its closed position against unauthorised opening.

The foregoing and further features of the invention may be more readily understood from the following description of a preferred embodiment thereof, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a front elevational view of a busway tap-off entry; Fig. 2 is a plan view of the busway tap-off entry of Fig. 1; Fig. 3 is an end sectional view of the busway tap off entry of Figs. 1 and 2; Fig. 4 is a front elevational view of a lever, on enlarged scale, utilised in the arrangement of Figs 1 to 3, and Fig. 5 is a front elevational view of a spring utilised with the lever of Fig. 4.

Referring now the drawings there is shown a busway 10 including a tap-off entry 11 formed therein. The entry 11 comprises four apertures 12 each with a male electrical contact 13 (Fig.3) located therein and each contact 13 having a portion 14 of electrically insulating material located thereover.

A cover 15 is slidably mounted in the framework of busway 10, is resiliently urged to its closed position, covering apertures 12, by extension springs 16 and is manually moveable by handle portion 17 to an open position as denoted at 15a and 17a. The cover 15 is normally locked in its closed position by a spring loaded lever release mechanism 18 which comprises a pivotally mounted lever 19 having a first lever arm 19a having a catch portion 19b normally spring urged into engagement with cover 15 by a spring 20 (Fig. 5) located over pivot pin 21 and acting on second lever arm l9c.

When a tap-off box 22 (Fig.3) is required to be connected to the tap-off entry 11 an operator locates such box 22 over the busway 10 such that a hook arm 23 engages with lever arm 19c to pivot lever 19 and disengage catch portion 19b of lever arm 19a from cover 15. The operator then holds box 22 with one hand and moves cover 15 by handle 17 with the other hand to the open position at which time box 22 can be pivoted downwardly to engage female electrical contacts 24 thereof with the male electrical contacts 13 of entry 11 as denoted by 24a in Fig. 3, a locating pin 25 ensuring correct alignment thereof. Once the box 22 is connected lever 19 returns to its original position and catch portion 19b engages with cover 15 to retain it in its open position.

When base 22 is to be disconnected it is pivoted upwardly which again releases catch portion 19b from cover 15 and allows such cover 15 to return to its closed position by action of the extension springs 16.

The cover 15 may be locked against unauthorised opening by a sealed wire or a padlock.

By ensuring that both hands of an operator are occupied during connection of box 22 to entry 11, the operator cannot accidentally insert fingers into apertures 12 of entry 11.

Claims

1. Electrical connection means comprising a busway tap-off entry, to facilitate connection and disconnection of a tap-off box thereat, the entry including a manually openable slidable cover normally locked in its closed position and locking means arranged to be disengaged upon mechanical location of a tap-off box onto the top of the busway above the entry to enable manual opening of the slidable cover and electrical connection of the tap-off box with the busway tap-off entry.

2. Electrical connection means as claimed in claim 1 wherein the locking means comprises a spring loaded release mechanism having a levered catch normally spring urged into engagement with the slidable cover when in its locked and closed position and having an attached lever arm for engagement mechanically by a tap-off box to cause disengagement of said levered catch from the slidable cover.

3. Electrical connection means as claimed in claim 2 wherein said levered catch is also arranged to engage the slidable cover in its open position to lock it in such open position, further spring means being located to move the slidable cover to its closed position upon movement of the tap-off box, after disengagement of the electrical connection with the busway tap-off entry, by further mechanical connection with said lever arm to disengage the levered catch from engagement with the slidable cover.

4. Electrical connection means as claimed in claim 3 wherein said further spring means comprise a pair of extension springs.

5. Electrical connection means as claimed in any preceding claim wherein electrical connectors of the busway entry each comprise male connectors for engagement by corresponding female connectors of the tap-off box, each of said male connectors being located in a separate aperture of the busway entry and having a member or portion of electrically insulating material located over the outer extremity thereof.

6. Electrical connection means as claimed in any preceding claim wherein said cover comprises a generally sheet-form member, of electrically insulating material, having handle means integally formed therewith at one end thereof.

7. Electrical connection means as claimed in any preceding claim wherein said cover is formed for attachment of safety locking means for locking the cover in its closed position against unauthorised opening.

8. Electrical connection means substantially as hereinbefore described with reference to the accompanying drawings.

9. An electrical busway including electrical connection means as claimed in any preceding claim.