GB2327158A

GB2327158A - Fuse-holder

Info

Publication number: GB2327158A
Application number: GB9714457A
Authority: GB
Inventors: James Beaney
Original assignee: Weidmueller Ltd
Current assignee: Weidmueller Ltd
Priority date: 1997-07-08
Filing date: 1997-07-08
Publication date: 1999-01-13
Anticipated expiration: 2017-07-08
Also published as: DE69825375T2; GB9714457D0; EP0899820A3; DE69825375D1; EP0899820B1; GB2327158B; EP0899820A2

Abstract

An electrical fuse-holder 16 comprises an insulating plastics housing 26, having a cavity 28 for a fuse 30, connectors (32, 34 Figure 6) mounted in the housing electrically connecting the fuse to a terminal block 14, the block 14 and the holder 16 being adapted so that the holder can be plugged into the block through apertures 24a, 24b either way round, relative to an axis 25 of the holder 16. The portion (26a Figure 2) of the housing formed with the cavity is located wholly to one side of said axis, whereby two adjacent holders, plugged opposite ways round into adjacent blocks become stacked together so that said portion of each fuse is located to one side of the corresponding portion of the other holder, thereby minimising the thickness of the stack. The connectors (32, 34) are located in the holder which is closed off by a living hinge (38). An aperture 26e allows cooling air to circulate around the holder. End plates 18 for the holders are provided. The terminal block 14 is mounted on a rail 12.

Description

1 Fuseholder 2327158

Field of the invention

This invention relates to an electrical fuseholder for use with an electrical terminal block which, in use, is mounted on a mounting rail.

The term -terminal block" herein means, and is defined as, a terminal block having a length, transversely of the rail, and a height, perpendicular to the rail, both much greater than a thickness of the terminal block, in the longitudinal direction of the rail, and the terminal block being adapted to be stacked with other such terminal blocks along the mounting rail.

Prior art With prior art electrical fuseholders for use with electrical terminal blocks mounted on a mounting rail, if the cartridge fuse is of x mm diameter, x being an arbitrary dimension, for example, 5 mm, the pitch of the terminal blocks must be greater than x mm in order for the cartridge fuse to be accommodated in the fuseholder.

It is an object of the invention to overcome this disadvantage and to enable the terminal blocks to be mounted (on the mounting rail) with a pitch equal to x min.

Summary ofthe invention According to the invention there is provided an electrical fuseholder for use with a railmounted electrical terminal block of the type defined, the fluseholder comprising an insulating plastics housing, a portion of the housing being formed with a cavity for a cartridge fuse, and two conductor elements mounted to the housing, one portion of each conductor element forming a respective one of two contacts for the fuse, another portion of each conductor element forming a respective one of two external contacts of the

2 fuseholder, for plugging into the terminal block and making electrical contact with two corresponding internal electrical contacts of the terminal block, characterised in that the terminal block and the fuseholder are adapted so that the fuseholder can be plugged into the terminal block selectively one way round or an opposite way round, relative to an axis of the fuseholder, and in that said portion of the housing formed with the cavity for the cartridge fuse is located wholly to one side of said axis, whereby, in use, two mutually adjacent such fuseholders, plugged opposite ways round into mutually adjacent, stacked, terminal blocks mounted on a mounting rail, become stacked together so that said portion of the housing formed with the cavity for the cartridge fuse of each fuseholder is located to one side of said portion of the housing formed with the cavity for the cartridge fuse of the other fuseholder.

Preferably, said portion of the housing formed with the cavity for the cartridge fuse is the thicker one of two portions of the housing of different thickness, the thinner portion being located wholly to the other side of said axis, whereby, in use, said two mutually adjacent such fuseholders, plugged said opposite ways round into said mutually adjacent, stacked, terminal blocks mounted on said mounting rail, become stacked together so that the thicker housing portion of each fuseholder becomes stacked with the thinner housing portion of the other fuseholder.

Preferably, the housing is formed with a step change in thickness between the thicker housing portion on the one hand and the thinner housing portion on the other hand.

Preferably, the two terminal blocks can be stacked on the mounting rail at a minimum pitch of x mm, where x is an arbitrary dimension, the thickness of said portion of the housing formed with the cavity for the cartridge fuse being greater than x mm in thickness.

Preferably, the thickness of the thinner housing portion is less than x mm in thickness.

3 Preferably, x is 5 mm.

Preferably, the thicker one of said two portions of the housing has a maximum thickness of 6mm and the other one of said two portions of the housing has a maximum thickness of 4 mm.

Preferably, the fuseholder is adapted for use with a cartridge fuse of x mm diameter.

Preferably, the fuseholder is adapted so that the fuse, when inserted properly into the fuseholder, extends in the direction of the height of the terminal block and perpendicularly to the width and the length of the mounting rail.

The invention will be described further, by way of example only, with reference to the drawings.

Brief description of the drawings

FIG. 1 is an exploded perspective view of a mounting rail, two stacked (but unmounted) electrical terminal blocks, two electrical fuseholders and an end backing plate, embodying the invention; FIG. 2 is a perspective view of the two fuseholders of FIG. 1, stacked in readiness to be plugged into the two terminal blocks of FIG. I; FIG. 3 is a side elevation of the two fuseholders of FIG. 2; FIG. 4 is a side elevation of three stacked fuseholders; FIG. 5 is a perspective view of the three fuseholders of FIG. 4, and a backing plate; and FIG. 6 is a perspective view of a fuseholder in partly finished state, together with a backing plate.

Detailed description ofpreferred embodiment of the invention

Referring to FIG. 1, there is shown (exploded) an electrical terminal block and fuseholder installation 10 which comprises a mounting rail 12, two identical electrical 4 terminal blocks 14a, 14b, two corresponding identical electrical fuseholders 16a, 16b and a backing plate 18.

In FIG. 1, arrows 20A, 20B and 20C respectively indicate directions transversely of the rail 12, perpendicularly to the rail 12 and longitudinally of the rail 12. It is readily apparent that each terminal block 14 has a length, transversely of the rail 12, and a height, perpendicular to the rail 12, both much greater than the thickness of the terminal block 14 in the longitudinal direction of the rail 12. The two terminal blocks 14a, 14b are stacked with each other along the mounting rail 12, at a pitch - the dimension "x--referred to above - of 5mm. Each terminal block 14 has two resilient feet 22a, 22b, one at each end of the terminal block 14, to engage the undersides of two side flanges 12a, 12b of the rail 12. There will usually be many more than just two terminal blocks 14 mounted on, and stacked along, the rail 12, at 5 mm intervals the 5mm pitch "x " referred to above. Each terminal block 14 can be snapped onto and off the rail 12 without disturbing the other terminal blocks 14. Such terminal blocks are well known in the art and detailed description of every feature of the terminal block 14 is believed to be unnecessary. However, attention is drawn to an aperture 24a, 24b in the top of each terminal block 14a, 14b, for the respective fuseholder 16a, 16b to be plugged into and unplugged from the terminal block 14a, 14b.

The two fuseholders 16a, 16b are shown in FIG. 1 with fuseholder 16a in one of the two possible required orientations and fuseholder 16b in the other required orientation for the fuseholder 16 to be plugged into the associated terminal block 14. Changing between the two orientations involves simply rotating either fuseholder 16 by 180' around its axis of symmetry 25, parallel to direction 2013.

Each fuseholder 16 comprises a unitary insulating plastics housing 26 which is formed (FIG. 6) with a cavity 28 for a standard type of cartridge fuse 30 of 5mm diameter. The cavity 28 is open at one side of the housing 26, as shown in the drawings. The fuseholder 16 also comprises two, two-leaved, conductor elements 32, 34 mounted to the housing 26. The cartridge fuse 30 is oriented perpendicularly to the rail 12, i.e.

parallel to direction 20B. The conductor element 32 comprises a two-arm portion 32a clipped around the bottom contact 30a of the cartridge fuse 30, whilst the conductor element 34 comprises a two-arm portion 34a clipped around the top contact 30b of the cartridge fuse 30. The conductor element 32 also comprises an external two-blade spring-contact portion 32b, whilst the conductor element 34 comprises an external twoblade spring-contact portion 34b. The two external spring-contact portions 32b, 3)4b project downwardly side-by-side as shown, for plugging into the terminal block 14 through the aperture 24, to make contact respectively with two internal electrical contacts (not shown) of the terminal block 14.

The housing 26 is formed (FIG. 1) with two portions of different thickness (in the longitudinal direction 20C of the rail 12. One portion 26a is 6mm - i.e. a dimension (x + 8) - thick whilst the other portion 26b is only 4 mm - i.e. a dimension (x - 6) thick. There is a step change at 26c between the two portions 26a, 26b, the step at 26c extending perpendicularly to the rail 12 along the axis of symmetry 25, Le. in the direction 20B. The fuse cavity 28 is in the thicker portion 26a. A wall 26d, at the "closed" side of the cavity 28, has an aperture 26e to help air circulation around the cartridge fuse 30.

As shown in FIG. 1, the fuseholder 16b is the opposite way round to fuseholder 16a, that is, it has been rotated 180' about an axis parallel to direction 20B, so that the thicker housing portion 26a of fuseholder 16a faces the thinner housing portion 26b of fuseholder 16b, and vice versa. The pitch of the external fuseholder contacts 32b, 34b is x = 5mm, the same as the pitch of the terminal blocks 14a, 14b on the rail 12.

Of course, it is desirable and necessary to provide sufficient clearances to allow for dimensional tolerance variation.

FIGS. 4 and 5 show the two fuseholders 16a, 16b stacked with a third fuseholder 16c, in the order 16a, 16b, 16c. It is preferable for the third fuseholder 16c to be oriented the same way as the first one, 16a.

6 How ever many fuseholders 16 are stacked together, one end one is likely to have the fuse dangerously exposed, as shown in FIGS. 1, 2 and 5, so the end plate 18 is required to cover it in as shown. The end plate 18 has an aperture 18a corresponding to the aperture 26e (FIG. 1). The end plate 18 also has four fixing pegs 18b- 1 8e which locate respectively in four holes 26P26i in housing 26.

In FIGS. 1-5, each fuseholder 16 is shown in finished, fully assembled, form. FIG. 6 shows the fuseholder 16 before a flap 36, joined integrally to the main body of the housing 26 by a "live" (i.e. integral) hinge 38, is closed over to engage three pegs 36a36c of the flap in three further holes 26j-261 in the main body of housing 26.

In a modification, not illustrated, the thin housing part 26b is omitted and each thick housing part 26a faces a gap where the thin housing part 26b was. This may be useful for high density stacks where x is small. The thick portion 26a in this case may have a thickness approaching 2x. That is, the gap may vanish.

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Claims

CLAIMS:

1. An electrical fuseholder for use with a rail-mounted electrical terminal block of the type defined, the fuseholder comprising an insulating plastics housing, a portion of the housing being formed with a cavity for a cartridge fuse, and two conductor elements mounted to the housing, one portion of each conductor element forming a respective one of two contacts for the fuse, another portion of each conductor element forming a respective one of two external contacts of the fuseholder, for plugging into the terminal block and making electrical contact with two corresponding internal electrical contacts of the terminal block, characterised in that the terminal block and the fuseholder are adapted so that the fuseholder can be plugged into the terminal block selectively one way round or an opposite way round, relative to an axis of the fuseholder, and in that said portion of the housing formed with the cavity for the cartridge fuse is located wholly to one side of said axis, whereby, in use, two mutually adjacent such fuseholders, plugged opposite ways round into mutually adjacent, stacked, terminal blocks mounted on a mounting rail, become stacked together so that said portion of the housing formed with the cavity for the cartridge fuse of each fuseholder is located to one side of said portion of the housing formed with the cavity for the cartridge fuse of the other fuseholder.

2. A fuseholder as claimed in claim 1, wherein said portion of the housing formed with the cavity for the cartridge fuse is the thicker one of two portions of the housing of different thickness, the thinner portion being located wholly to the other side of said axis, whereby, in use, said two mutually adjacent such fuseholders, plugged said opposite ways round into said mutually adjacent, stacked, terminal blocks mounted on said mounting rail, become stacked together so that the thicker housing portion of each fuseholder becomes stacked with the thinner housing portion of the other fuseholder.

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3. A fuseholder as claimed in claim 2, wherein the housing is formed with a step change in thickness between the thicker housing portion on the one hand and the thinner housing portion on the other hand.

4. A fuseholder as claimed in claim 1, 2 or 3, wherein said two terminal blocks can be stacked on the mounting rail at a minimum pitch of x mm, where x is an arbitrary dimension, the thickness of said portion of the housing formed with the cavity for the cartridge fuse being greater than x mm in thickness.

5. A fuseholder as claimed in claim 4 dependent from claim 2 or 3, wherein the thickness of the thinner housing portion is less than x mm in thickness.

6. A fuseholder as claimed in claim 4 or 5, wherein x is 5 mm.

7. A fuseholder as claimed in claim 6 dependent from claim 2 or 3, wherein the thicker one of said two portions of the housing has a maximum thickness of 6mm and the other one of said two portions of the housing has a maximum thickness of 4 mm.

8. A fuseholder as claimed in any one of claims 4 to 7, adapted for use with a cartridge fuse of x nim diameter.

9. A fuseholder as claimed in any preceding claim, adapted so that the fuse, when inserted properly into the fuseholder, extends in the direction of the height of the terminal block and perpendicularly to the width and the length of the mounting rail.