GB2031235A - Contact elements for fuses - Google Patents

Abstract

The invention is concerned with a contact element suitable for an electrical fuse having a conical nose and the element is made from an elastic metallic strip which is a good electrical conductor, the strip having at one end ears 9 for connection to the conductor and, close to its other end, a seating 13 for the conical end of the fuse, the seating being carried by an extension 2 terminated by a lug 4 bearing against the strip. The contact element may be mounted on a printed circuit plate in a fuse box. A second embodiment provides a base reinforcing strip (19, Figure 6, not shown). <IMAGE>

Description

SPECIFICATION Contact elements for fuses The present invention relates to a contact element for a fuse and intended for use with oblong fuses terminated at their ends by conducting conical points or noses which are connected by a fuse wire.

Generally, such fuses are carried by contact elements arranged in pairs in a fuse box, each contact element comprising a connecting strip, of which one end is fast with the box and comprises means for connection to an electrical conductor, while the other part close to the free end has means for receiving and retaining one of the conical ends of the fuse.

These retaining or holding means are formed either by a simple hole, or by a corresponding shaped part. The spacing between two contact elements of a pair is less than the length of a fuse, so that the positioning of the latter is effected by means of an elastic deformation of the said elements.

Such contact elements have a certain number of disadvantages. In practice, they have to be made of a resilient material having a certain thickness, so that there is no danger of them being bent, but this leads to them having to be given a relatively great length, so that they nevertheless provide a certain flexibility, permitting the fuses to be introduced between them.

Moreover, the tolerances in such fuses are considerable, so that either they are difficult to place in position, or they are not sufficiently gripped between the two corresponding elements and the contact is imperfect.

The present invention seeks to provide contact elements for a fuse which overcomes the various disadvantages mentioned above.

The contact element according to the invention is adapted to be used with fuses of the oblong type, formed of an elongated insulating body with two conductive conical points or noses, one at each end, connected by a fuse wire, the said contact element being of the type formed from a resilient metal strip which is a good conductor of electricity and which has at one end means for its connection to a conductor and, close to its other end, a seating designed to receive one conical nose, the said seating being carried by an extension of the end of the resilient metal strip which is opposite to that provided with the connection means, the said extension being bent so as to extend in the direction of the end provided with the connection means, and the extension being terminated by a tab or lug which is bent over so as to extend between the said extension and the said strip and to bear against the latter, a central longitudinal slot being formed between the seating and the bent part of the said extension.

Because of this arrangement, it is possible to reduce the height of the element, since it becomes possible to use a much thinner material, while being assured of a perfect contact and a good support of the fuse, due to the elastic action of the extension being reinforced by that of the tab or lug.

Furthermore, the elastic deformation of the exten sion for the introduction of the fuse can be much greater, so that such an element is able to take up the considerable tolerances in the length of the fuses.

Finally, the introduction of the fuse is facilitated, since it is guided between the sides of the slot.

Preferably, the lug or tab is slotted longitudinally.

In order to reinforce the contact element and to avoid lateral deformations of the extension and of the lug, the strip preferably comprises a lateral wing on each side close to the connection means, the wings being folded or bent so as to extend parallel on either side of the extension.

Finally, according to yet another preferred characteristic of the construction, the strip is extended from the side adjacent to the connection means by a connecting strip which is bent so as to extend between the wings perpendicularly of the latter. In this way, the element according to the invention is still further reinforced.

The invention will now be described in greater detail by reference to particular constructional forms, which are given simply by way of example and which are shown in the accompanying drawings, wherein: Figure lisa plan view of a strip cut out to form a contact element according to the invention; Figure 2 is a view in elevation of a contact element made from the strip shown in Figure 1; Figure 3 is a sectional view along the line Ill-Ill of Figure 2; Figure 4 is a view similar to Figure 3, showing the end of a fuse introduced into the corresponding seating; Figure 5 is a plan view of a cut-out strip for a modified embodiment of the contact element; and Figure 6 is a sectional view of the contact element made with the strip of Figure 5.

Represented in Figures 1,2 and 3 is a first embodiment of the contact element according to the invention.

The contact element is made from a resilient metallic strip which is a good electrical conductor and which is cut out to provide (Figure 1 ) a main part 1 formed with an extension 2, terminated by two lugs 3 and 4 defined by a slot 5.

The end of the main part 1 opposite to the lugs 3 and 4 comprises two wings 6 and 7, each provided with an ear 8 and 9, respectively.

The wings 6 and 7 are bent parallel to one another and perpendiculartothe main part 1, so as to form a "U" shaped part 10.

Cut out in he main part 1 and in the extension 2 is a slot 12, wi- ich opens out in the said extension as a hole 13, the -im of which is dished.

As will be seen in Figures 2 and 3, the extension is folded over so as to extend between the wings 6 and 7, while the lugs 3 and 4 are bent so as to bear against the main part 1.

Such a contact element is designed to be mounted on a printed circuit plate in a fuse box or in a similar device and is adapted to support the corresponding end of an oblong fuse 15 (see Figure 4), formed of an insulating body 16, of which the ends are each provided with a conductive conical nose 17, the noses being connected by a fuse wire.

The contact elements are arranged in pairs, the extensions 2 of two contact elements of a pair being turned to face one another and the distance separating the holes 13 of the two said contact elements of a pair being smaller than the length of a fuse 15.

The fuse 15 is placed in position by a first end being directly engaged in the hole 13 of one contact element and by the other end being guided between the sides of the slot 12 and then being seated in the corresponding hole of the other said element.

As may be perfectly seen in Figure 4, when the fuse 15 is placed in position, it tends to push back the extension 2 in the direction of the main part 1 against the resilient action, firstly of the said extension and secondiy of the lugs 3 and 4 which bear against the said main part 1.

It is seen that, once the fuse has been placed in position, it is perfectly held and that its engagement with the element is nevertheless very easy. The ears 8 and 9 permit the contact element to be fixed on a device 23 designed for receiving it and the free end thereof can be bent over to permit the fixing of a flexible conductor 18.

The ears 8 and 9 may be formed with a cut-out part 22 adapted to be bent over against the corresponding face of the device 23, in order to ensure the fixing of the contact element.

Shown in Figures 5 and 6 is a modified constructional form of the invention, which has small differences as compared with the embodiment as previously described.

In these figures, therefore, the same references are used for designating the same parts as those in Figures 1,2,3 and 4, the said references having added thereto the letter "a".

In this second embodiment, a supplementary connecting strip 19 is provided, which is adapted to be bent over between the wings 6a and 7a, so as to reinforce the base of the contact element, the said strp 19 being extended by a tab 20.

It is obvious that the invention is not limited to the embodiments which have just been described and which have been illustrated, and it will be possible to incorporate numerous modificatons as regards details, without thereby departing from the scope of the invention.

Claims (7)

1. Contact element, suitable for a fuse of the oblong type formed of an elongated insulating body with two conical points or noses, one at each end, connected by a fuse wire, the said contact element being formed with an elastic metallic strip which is a good conductor of electricity, having at one end means for its connection to a conductor and, close to its other end, a seating adapted to receive one conical nose, the said seating being carried by an extension of the end of the elastic metallic strip opposite to that provided with the connection means, the said extension being bent over so as to extend in the direction of the end provided with the connection means, the extension being terminated by a lug bent over in such a way as to extend between the said extension and the said strip and to bear against the latter and a central longitudinal slot being formed between the seating and the bent-over part of the said extension.

2. Contact element according to claim 1, wherein the lug is slotted longitudinally.

3. Contact element according to claim 1 or 2, wherein the strip comprises a lateral wing on each side close to the connection means, the wings being folded so as to extend parallel on either side of the extension.

4. Contact element according to claim 3, wherein the strip is prolonged from the side adjacent to the connection means by a connecting strip folded so as to extend between the wings perpendicularly of these latter.

5. A contact element according to claim 1 substantially as described herein.

6. A contact element substantially as shown in Figures 1 to 4 or 5 and 6 of the accompanying drawings and described herein with reference thereto.

7. A fuse box comprising at least one fuse carried by a pair of contact elements according to any one of the preceding claims.