Electric fuse

Abstract

A safety fuse for use in a motor vehicle includes which fuse comprises a first contact metal portion, a second contact metal portion and a melting metal section connecting the first contact portion to the second contact portion. The melting section is enclosed by a casing made from a non-conductive material and includes two hollow half-shells provided with mutual coupling elements, each half-shell having an inner surface facing the melting section and an outer surface facing outside of the fuse. At least one of the half-shells is provided on at least part of the inner surface of an alveolar structure with open cells in the direction of the melting section. The alveolar structure is formed by a plurality of walls protruding from the inner surface and intersected with each other.

Claims

1. A safety fuse for use in a motor vehicle, comprising: a first contact metal portion; a second contact metal portion; and a melting metal section connecting the first contact portion to the second contact portion, the melting metal section being enclosed by a casing made from a non-conductive material, the casing having two hollow half-shells provided with mutual coupling means, each half-shell having an inner surface facing the melting metal section and an outer surface facing outside of the fuse, wherein at least one of the two hollow half-shell is provided on at least part of an inner surface of an alveolar structure having open cells, said open cells being arranged in a plurality of rows and columns and being open in a direction of the melting metal section, the alveolar structure having a plurality of walls protruding from said inner surface and intersected with each other.

2. The fuse according to claim 1, wherein the alveolar structure is provided only in the half-shell facing the melting metal section.

3. The fuse according to claim 1, wherein the first contact metal portion, the second contact metal portion, and the melting section lie on a common plane and said walls are perpendicular to the said common plane.

4. The fuse according to claim 3, wherein top edges of said walls define a surface of the alveolar structure, which surface of the alveolar structure is flat and parallel to said common plane.

5. The fuse according to claim 4, wherein, in an assembled condition of the fuse, the ssurface of the alveolar structure is closer to the melting section than to the inner surface of the respective half-shell.

6. The fuse according to claim 1, wherein the walls are arranged perpendicular to each other and form rectangular-base cells.

7. The fuse according to claim 6, wherein the walls form square-base cells.

8. The fuse according to claim 1, wherein the walls are made of a non-conductive material.

9. The fuse according to claim 1, wherein the melting metal section is shaped according to a loop and the casing in an assembled condition of the two half-shells has an intermediate wall, the intermediate wall being positioned inside said loop and being connected to both half-shells.

10. The fuse according to claim 9, wherein said intermediate wall is integrally formed with one of the two half-shells.

11. The fuse according to claim 9, wherein at least part of the first metal contact portion and at least part of the second metal contact portion freely protrude from the casing in respective opposite directions along a common straight direction, the intermediate wall being provided arranged perpendicularly to the straight direction in an assembled condition of the casing.

12. The fuse according to claim 9, wherein the intermediate wall extends inside a cavity and across the casing, the intermediate wall having opposite sides each facing a plurality of the open cells.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features and advantages of the present invention will become clearer from the following description of some non-limiting exemplary embodiments illustrated in the attached drawings in which:

(2) FIG. 1 illustrates the fuse in the assembled condition;

(3) FIG. 2 illustrates an exploded view;

(4) FIG. 3 illustrates the assembly of the metal part and the first half-shell;

(5) FIGS. 4 and 5 illustrate different views of the first half-shell;

(6) FIG. 6 illustrates the assembly of the metal part and the second half-shell;

(7) FIGS. 7 and 8 illustrate different views of the second half-shell.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(8) An embodiment example is illustrated in the figures of the safety fuse for use in a motor vehicle according to the present invention.

(9) The fuse comprises a conductive metal part 1 consisting of joining a first contact metal portion 10, a second contact metal portion 12 and a melting metal section 11 connecting the first contact portion 10 with the second contact portion 12. The contact portions 10 and 12 are plate-like. The first contact portion 10, the melting section 11 and the second contact portion 12 lie on a common plane, and the metal portion 1 therefore consists of a flat and suitably shaped metal plate. The shape is such that the melting section 11 is shaped according to a loop. The metal part 1 may be of any metal material suitable for use in a safety fuse, preferably it consists of tinned copper.

(10) However, other geometries may also be provided, for example the contact portions 10 and 12 may also not lie on a common plane.

(11) The melting section 11 is enclosed by a casing 2 made of a non-conductive material. Any non-conductive material suitable for use to enclose the melting section 11 of the fuse may be used, for example a polymer. Preferably, the non-conductive material is a glass fibre reinforced polyamide, in particular with a glass fibre content between 30 and 50%.

(12) The first contact portion 10 and the second contact portion 12 freely protrude from the casing 2 in respective opposite directions along a common straight direction. It is possible that the contact portions 10 and 12 completely protrude from the casing 2 or alternatively that the contact portions 10 and 12 only partially protrude from the casing 2. An alternative configuration may also be provided in which the contact portions do not protrude in opposite directions of the same straight direction, but for example form an angle, a U-shaped configuration, an S-shaped configuration in which the contact portions protrude in opposite directions perpendicular to the longitudinal axis of the melting section 11, or the like.

(13) The casing 20 consists of a first hollow half-shell 20 and a second hollow half-shell 21. Each half-shell 20 and 21 has an inner surface facing the melting section 11 and an outer surface facing outside the fuse.

(14) In the preferred embodiment illustrated in the figures, the two half-shells 20 and 21 have respective mutual contact edges which have complementary shapes for a shape coupling in the closed condition of the casing 2.

(15) The two half-shells 20 and 21 are also provided with removable mutual coupling means comprising two first pins 200 and two second pins 210 provided on the inner surfaces of the first half-shell 20 and the second half-shell 21, respectively, which pins 200 and 210 each extend in the direction of the opposite half-shell.

(16) The first half-shell 20 is provided with two first housing holes 201 of the second pins 210, while the second half-shell 21 is provided with two second housing holes 211 of the first pin 200, such that in the coupled condition of the two half-shells 20 and 21 each pin penetrates the corresponding hole provided on the opposite half-shell. This keeps the two half-shells 20 and 21 coupled in the closed condition of the casing 2.

(17) The metal part 1 is provided with four holes 121 in which the pins 200 and 210 are inserted into the coupling of the two half-shells 20 and 21. Therefore, in the assembled condition the fuse has the metal part 1 and the casing 2 locked in the operating position thereof.

(18) Although the embodiment presented is the preferred embodiment, it is still possible to provide for mutual coupling means of the two half-shells 20 and 21 which cannot be removed, in which the fuse, once assembled, can no longer be broken down into the constituent components thereof.

(19) The half-shells 20 and 21 are provided on the inner surface of an open-cell alveolar structure 3, which cells 31 in the assembled condition of the fuse expose the opening thereof in the direction of the melting section 11.

(20) In the preferred embodiment illustrated in the figures, both half-shells 20 and 21 are provided in the inner surface of the alveolar structure 3. However, it is possible to provide the alveolar structure 3 only on one half-shell. The alveolar structure 3 may also be provided on the entire inner surface or on at least part thereof. If the casing also covers part of the contact portions, the alveolar structure 3 is advantageously provided only at the melting section 11. The melting section 11 is covered on both sides and substantially in the entirety thereof by the alveolar structures 3 of the two half-shells 20 and 21 in the coupled condition.

(21) The alveolar structure 3 consists of a plurality of walls 30 protruding from the inner surface of the respective half-shell 20 or 21, which walls 30 are intersected with each other to form said cells 31 open in the direction of the metal part 1 in the assembled condition of the fuse. In the embodiment of the figures, the walls 30 are positioned perpendicular to the common plane on which the metal part 1 lies and are arranged perpendicular to each other to form rectangular-base cells 31, in particular square-base cells 31. However, it is possible to envisage an alveolar structure 3 with other geometries, for example with rhomboidal or hexagonal cells, without departing from the objects of the present invention.

(22) The top edges of the walls forming the alveolar structure 3 define a surface of the alveolar structure 3 itself. Such surface of the alveolar structure 3 is flat and parallel to the common plane on which the metal part 1 lies, and is closer to the melting section 3 than to the inner surface of the respective half-shell 20 or 21.

(23) The walls 30 forming the alveolar structure 3 are integrally formed with the related half-shell 20 or 21, preferably by moulding, for example injection moulding. The walls 30 are thus made of the same non-conductive material which forms the casing 2. It is optionally possible to provide an alveolar structure 3 consisting of an independent element, of non-conductive material, which can be inserted inside the casing 2.

(24) The alveolar structure 3 of the first half-shell 20 is divided into two parts separated from each other, to form in the centre a housing compartment in which an intermediate wall 4 integrally formed with the second half-shell 21 is positioned, in the assembled condition of the fuse.

(25) In the assembled condition of the fuse, the intermediate wall 4 is positioned inside the loop formed by the melting section 11 and is provided perpendicular to the straight direction along which the two contact portions 10 and 12 protrude from the casing 2.

(26) In the assembled condition of the casing 2, the intermediate wall 4 is at least partially in contact with the inner surface of the first half-shell 20, such that it is connected to both half-shells 20 and 21.