FR2783639A1 - Spring mounted sliding electrical contact for phone includes support within axial hole inside contact ensuring constant good electrical connection - Google Patents

Abstract

The contact includes an internal spring element ensuring a good electrical connection. The contact element (5) is mounted to slide within a body (4) against the action of a spring (6). At the end of the body opposite the contact there is a projecting peg (8) enabling connection with an electrical conductor. The body (4) houses a further conducting element (9) which connects the contact element (5) to the peg (8). The conducting element (9) is cut from sheet material and folded into a U-shape. The central part of the U makes contact with the inside surface of the peg (8), whilst the two projecting limbs (12) engage an axial bore (13) inside the sliding contact element (5). The two limbs thus serve to make contact with the sliding contact element whilst also assisting the alignment of the contact within the body (4).

Description

Contact comprising a cylindrical body and a mounted contact element

  sliding in this body The present invention relates to a contact comprising a cylindrical body and a contact element

mounted sliding in this body.

  The invention relates in particular to a piston contact of the type used for example in chargers for mobile phone batteries. This type of contact must be designed to withstand a large number of uses under an application stress of maximum 1 N, this force being applied in the direction of the axis of the piston, that is to say normally on the receiving surface. It must also allow a

  large clearance relative to the height of the insulation.

  Two major technical problems arise with this type of application. The first relates to the size of the contact or group of contacts used in a miniaturized environment. The second relates to the contact resistance which must of course be as low as possible to allow a

effective charge.

  In a known solution, the electrical connection between the sliding contact element and the end of the body intended to be connected to a conductor is

  consisting of a cut metal blade.

  This embodiment, although making it possible to ensure correct contact, has a certain number of drawbacks. The disadvantages are relative on the one hand, to the wear of the internal parts of the contact because the latter works on the cut edges. This results in a very significant reduction in the number of possible maneuvers. On the other hand, the contact resistance is relatively high due to a small effective surface ensuring contact, which leads to heating due to the loss of energy.

transformed into heat.

  The object of the present invention is to very significantly reduce the internal wear of the contact and the contact resistance of the latter. The invention thus relates to a contact comprising a cylindrical body and a contact element slidably mounted in this body against the action of a return spring housed in said body allowing a long displacement of the contact, the latter bearing at its end opposite to the contact element means for establishing an electrical connection with a conductor, the body further containing a conductive element connecting the contact element and said means

  to establish a connection.

  According to the invention, this contact is characterized in that the conductive element is a strip of conductive metal cut and folded, comprising one end in contact with said means making it possible to establish a connection and another end constituted by two branches engaged in an axial bore of the contact element and whose ends bear

  elastically on the surface of said bore.

  Preferably, the ends of the branches of the blade each carry a cylindrical surface matching the

cylindrical surface of said bore.

  This arrangement reduces wear and

  to decrease the contact resistance.

  Also preferably, the cylindrical surface of said ends of the branches is produced by folding. This results in a great simplification of

  the manufacture of the above contact blade.

  Other features and advantages of

  the invention will also appear in the description below

  after. In the accompanying drawings given by way of non-limiting examples: - Figure 1 is a longitudinal sectional view of a piston contact according to the invention; - Figure 2 is a perspective view of a

  contact blade of the piston contact according to the invention.

  Contact 1 shown in Figure 1 is housed in an insulating base 2, for example

  a mobile phone charger.

  The base 2 has for example a thickness of the order of 4 mm, while the diameter of the

contact is around 2 mm.

  The base 2 comprises several cells 3 which can

each receive a contact 1.

  It can be seen in FIG. 1 that the contact 1 comprises a cylindrical body 4 and a contact element slidably mounted in this body 4 against the action of a

  helical return spring 6 housed in the body 4.

  The body 4 carries at its end 7 opposite to the contact element 5 a tubular end piece 8 making it possible to establish an electrical connection with a conductor such as a pin of a printed circuit board in an electric wire or to be welded in CMS (components

surface mounted).

  The body also contains a conductive element 9 connecting the sliding contact element 5 and the end piece

8 tubular connection.

  According to the invention, the conductive element 9 is a cut and folded sheet of conductive metal, having one end 10 in contact with the tubular connection piece 8 and another end 11 constituted by two branches 12 engaged in an axial bore 13 of the contact element 5. The ends 11a of the branches 12 bear elastically on the

bore surface 13.

  As shown in FIG. 2, the ends 11a of the branches 12 of the blade 9 each carry a cylindrical surface 11b matching the cylindrical surface of the bore. This cylindrical surface llb of the ends lia

  branches 12 is made by bending.

  Figures 1 and 2 show on the other hand that the two branches 12 of the blade 9 meet in a zone 14 located at a certain distance from the end 10

  of the blade 9 opposite the branches 12.

  We also see in Figures 1 and 2 that the end 10 of the blade 9 has a flat surface bearing on the bottom 15 of the inner recess 16 of the body 4 and covering the opening 17 of the end piece

tubular 8.

  Furthermore, the blade 9 has two parts 18 which diverge towards the end 10 from the zone 14 and which are connected to this end 10 by

curved parts 19.

  On the other hand, the flat surface 10 of the end of the blade 9 is part of a cut-out part which projects beyond each side of the divergent parts 18 and which covers most of the bottom 15 of the recess

inside 16 of the body 4.

  When, for example, a mobile telephone is positioned on the base 2 for connecting a charger, the contact elements 5 slide from their bodies 4 according to a maximum stroke C. During this sliding, the cylindrical surfaces llb of the blade 9 rub on bore 13 and provide electrical contact to transmit electrical current to the conductor connected to

end piece 8.

  Thanks to the cylindrical surfaces llb of the blade 9 and to the elasticity of the branches 12, the friction of its surfaces llb on the bore 13 of the contact element 5 produces no significant wear and ensures minimal contact resistance because of of the extended surface actually in contact with on the one hand the bottom

and on the other hand the bore 13.

  Of course, the invention is not limited to the example which has just been described and many modifications can be made to it without departing from the

part of the invention.

6 2783639

Claims (8)

  1. Contact comprising a cylindrical body (4) and a contact element (5) slidably mounted in this body (4) against the action of a return spring (6) housed in said body (4), the latter bearing at its end (10) opposite the contact element (5) means (8) for establishing an electrical connection with a conductor, the body (4) further containing a conductive element (9) connecting the element contact (5) and said means (8) for establishing a connection, characterized in that the conductive element (9) is a blade of conductive metal cut and folded, having one end (10) in contact with said means (8) making it possible to establish a connection and another end (11) constituted by two branches (12) engaged in an axial bore (13) of the contact element (5) and whose ends (11a) are supported   elastically on the surface of said bore (13).   2. Contact according to claim 1, characterized in that the ends (11a) of the branches (12) of the blade (9) each carry a cylindrical surface (11b) matching the cylindrical surface of said bore (13).   3. Contact according to claim 2, characterized in that the cylindrical surface (11b) of said ends (11a) of the branches (12) is produced by folding.   4. Contact according to one of claims 1   to 3, characterized in that the two branches (12) of the blade (9) meet in a zone (14) located at a certain distance from the end (10) of the opposite blade to said branches (12).   5. Contact according to claim 4, characterized in that said end (10) of the blade (9) has a flat surface bearing on the bottom (15) of the internal recess (16) of the body (4).   6. Contact according to one of claims 4   or 5, characterized in that the blade (9) has two parts (18) which diverge towards said end (10) and from said zone (14) and which are connected to   this end (10) by curved parts (19).   7. Contact according to one of claims 5   or 6, characterized in that the flat surface of said end (10) of the blade (9) is part of a cut-out part which projects beyond each side of said divergent parts (18) and which covers most of the   bottom (15) of the interior recess (16) of the body (4).   8. Charger connection socket (2) for mobile telephone comprising several contacts (1)   according to one of claims 1 to 7.