GB2223630A

GB2223630A - A bus bar having a number of electrical contacts

Info

Publication number: GB2223630A
Application number: GB8820373A
Authority: GB
Inventors: Paul Jonathan Roberts; Michael Greenfield
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1988-08-26
Filing date: 1988-08-26
Publication date: 1990-04-11
Anticipated expiration: 2008-08-26
Also published as: GB2223630B; GB8820373D0

Abstract

A bus bar for use in a fuse box comprises a carrier strip (1) from which two rows of parallel electrical contacts (5, 9) project, each row being formed by a number of parallel, spaced apart electrical contacts. The contacts of one row can be aligned with the contacts of the other row or each contact of one row can be located between two adjacent contacts in the other row. In use the bus bar is located between two sets of terminals (21, 23) and can be connected, eg by fuses (26), to them. <IMAGE>

Description

DESCRIPTION IMPROVEMENTS RELATING TO A BUS BAR HAVING A NUMBER OF ELECTRICAL CONTACTS The present invention relates to a bus bar for use in a fuse box, having a number of electrical contacts.

In particular the present invention relates to a bus bar having a plurality of electrical contacts formed thereon or attached thereto. It is already known to provide a member with a number of electrical contacts which project at varying angles for contacting a movable member. However in a fuse box a bus bar having a single series of electrical contacts, is usually provided, together with a number of associated electrical terminals, the terminals and electrical contacts of the bus bar being interconnected as required by fuses. The number of electrical contacts is however normally relatively small so that the electrical load carrying capacity of the bus bar is of no great importance.

It is an aim of the present invention to provide a bus bar for use in a fuse box, the bus bar incorporating a relatively large number of electrical contacts as compared to prior art constructions, whilst still being of relatively compact physical configuration.

According to the present invention there is provided a bus bar comprising a carrier strip from which two rows of parallel electrical contacts project, each row being formed by at least two parallel electrical contacts.

In a preferred embodiment of the present invention the bus bar is formed by an elongate carrier strip having a U-shaped transverse configuration, with aligned pairs of electrical contacts projecting from the arms of the U-shape at equi-spaced apart locations along the length of the bus bar so as to give the bus bar an overall generally U-shaped transverse cross-section.

Each contact is formed by a pair of resilient jaws between which part of a fuse can be gripped.

Alternatively the parallel electrical contacts projecting from one arm of the U-shape may be each located between two adjacent electrical contacts projecting from the other arm of the U-shape.

In use, the bus bar of the present invention is located between rows of associated electrical terminals.

Each electrical terminal is aligned with an adjacent electrical contact on the bus bar of the present invention, so that fuses can be engaged with said electrical terminals and said electrical contacts of the bus bar.

The carrier strip of the bus bar of the present invention preferably has a number of indexing apertures provided along its length, said apertures being necessary to move the carrier strip through a stamping machine during manufacture, prior to and/or during bending. Alternatively, to maximise the electrical load carrying capacity of the carrier strip, the carrier strip may be stamped out with no indexing apertures, said indexing apertures being provided in an outrigger strip extending parallel to the carrier strip and connected thereto by spaced apart connection strips.

Subsequent to manufacture the outrigger strip may be detached.

Further, whilst the bus bar may be made wholly of brass i.e. as a unitary construction by stamping and bending, the bus bar may alternatively be made from a bimetallic strip e.g. from a strip with a central longitudinal copper region and brass edge regions or a brass strip with an elongate upper strip welded to its central longitudinal regions. By using such a prefabricated bimetallic strip, the electrical conductivity of the bus bar is enhanced i.e. by the copper region, whilst the required resilience of the electrical contacts is provided by the brass. Whilst brass is preferred for the electrical contacts any other electrically conductive resilient material may be used e.g. phosphor bronze, copper iron.

Whilst in the preferred embodiment of the present invention the carrier strip has a transverse U-shaped configuration to thus maximise the electrical load carrying capacity of the bus bar by maximising the volume of the bus bar whilst minimising its transverse physical configuration, the bus bar may, within the scope of the present invention, alternatively be merely a planar strip with the electrical contacts bent upwards from opposing side edges thereof.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a plan view of one embodiment of the present invention; Fig. 2 is an end view of the embodiment of Fig. 1, schematically illustrating its position in a fuse box in relation to two associated fuse clips and adjacent electrical terminals; and Fig. 3 is a cross-sectional view of part of a fuse box incorporating the arrangement of Fig. 2.

The embodiment of the present invention illustrated in the accompanying drawings, comprises a bus bar 1 formed by an elongate planar, carrier strip 3, with a series of parallel electrical contacts 5 projecting from its left edge 7 transverse to the longitudinal axis of the strip, as viewed in Fig. 1, and a further series of parallel electrical contacts 9 projecting in a similar manner from its right edge 11. The bus bar 1 thus has an overall generally U-shaped transverse configuration, as viewed in Figs. 2 and 3. Individual contacts 5 in one series are aligned with a corresponding contact 9 in the other series to thus form an aligned pair of contacts.In an alternative embodiment (not illustrated) the individual contacts in one series are staggered with respect to the contacts in the other series so that a contact in one series is effectively located between two adjacent contacts in the other series.

As shown the bus bar 1 is stamped and bent out of a sheet of metal e.g. from a brass sheet or a brass/copper bimetallic sheet. First the metal sheet is stamped to produce the developed bus bar and developed electrical contacts. The electrical contacts are then formed by bending, the sections 15 being thus formed with the end regions 17 of two adjacent sections 15 being bent inwardly, and back towards the carrier strip to form a pair of resilient jaws defining an electrical contact.

The above process can be completed in one machine.

However a further machine is necessary to bend the arms 13 of the U-shape to thus form the U-shaped bus bar 1 with parallel electrical contacts 5,9; this further operation being carried out after the stamped carrier strip has been cut into desired lengths. In an alternative embodiment of the present invention (not illustrated) the whole bus bar can be manufactured in one stamping and bending machine, the electrical contacts alone being bent out of the plane of the carrier strip to form the U-shape.

To allow for accurate stamping and bending, indexing apertures 19 are provided at spaced apart locations along the length of the carrier strip 3 to facilitate movement of the metal sheet through a stamping machine. However in an alternative embodiment (not illustrated) to provide for maximum electrical load carrying capacity, indexing apertures are not provided in the carrier strip but are provided in an outrigger strip which extends parallel to and to one side of the carrier strip, the outrigger strip being connected to the carrier strip by spaced apart transverse connection strips. The outrigger strip can thus be simply detached by fracturing the connection strip adjacent to the carrier strip, after manufacture.

In use, as shown in Figs. 2 and 3 of the accompanying drawings, the bus bar 1 is located between two parallel series of electrical terminals 21,23. Each terminal of these parallel series has an electrical contact 25, these latter electrical contacts 25 being aligned with said aligned pairs of contacts 5,9 on the bus bar 1. As shown, said series of electrical terminals 21,23 are located on opposite sides of the bus bar 1 , so that the electrical contacts 25 can be connected with an adjacent contact 5 or 9 of the bus bar 1 by a fuse 26.

The bus bar 1 is preferably made of brass to provide for resilient jaw contacts 5,9. However, to enhance electrical conductivity the bus bar can be made from a bimetallic strip e.g. from a strip with a central longitudinal copper region and brass edge regions, or a brass strip with an elongate copper strip (27) welded to its central longitudinally extending region. By using such a prefabricated bimetallic strip, the electrical conductivity of the bus bar is enhanced i.e. by the copper region, whilst the required resilience of the electrical contacts 5,9 is provided for by the brass.

As an alternative to brass any other electrically conductive resilient material can be used e.g. phosphor bronze, copper iron.

The present invention thus provides a bus bar with a relatively large number of electrical contacts in a physically relatively small configurations as compared to prior art constructions, with a large electrical load carrying capacity to thus cater for the use of all of the electrical contacts.

Claims

1. A bus bar comprising a carrier strip from which two rows of parallel electrical contacts project, each row being formed by at least two parallel electrical contacts.

2. A bus bar as claimed in claim 1, in which the carrier strip is elongate and has a U-shaped transverse configuration with aligned pairs of electrical contacts projecting from the arms of the U-shape as equi-spaced apart locations along the length of the bus bar.

3. A bus bar as claimed in claim 1, in which the parallel electrical contacts projecting from one arm of the U-shaped strip are each located between two adjacent electrical contacts projecting from the other arm of the U-shape.

4. A bus bar as claimed in any one of claims 1 to 3, in which each contact is formed by a pair of resilient jaws.

5. A bus bar as claimed in any one of claims 1 to 4, in which the carrier strip has a number of indexing apertures provided along its length.

6. A bus bar as claimed in any one of claims 1 to 4, in which an outrigger strip extends parallel to the carrier strip, the outrigger strip being connected to the carrier strip by spaced apart connection strips, and having a number of indexing apertures provided along its length.

7. A bus bar as claimed in any one of claims 1 to 6, in which the carrier strip is made wholly of brass.

8. A bus bar as claimed in any one of claims I to 6, in which the carrier strip is made of brass and an elongate copper strip is welded to the central longitudinal region of the carrier strip.

9. A bus bar as claimed in any one of claims 1 to 6, in which the carrier strip comprises a central longitudinal copper region with brass edge regions.

10. A bus bar constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.