Electrical connectors – Contact comprising cutter – Insulation cutter
Patent
1990-01-16
1991-01-08
Pirlot, David L.
Electrical connectors
Contact comprising cutter
Insulation cutter
295661, 439391, H01R 424
Patent
active
049831291
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a contact member, more specifically to a contact member with a bifurcated part comprising two legs and an intermediate slit, and disposed such that on transversal thrusting against an insulated conductor it penetrates the insulation and makes electrical contact with the conductor. The invention also relates to a tool for stamping a contact member in accordance with the invention.
BACKGROUND ART
Contact members with a bifurcated part formed such that on thrusting transversely against an insulated conductor they penetrate the insulation and make electrical contact with the conductor, so-called slit contact tips, are already known and are used in different connections for connecting conductors with each other in terminal boxes or for connecting conductors with electrical components in circuit boards or the like.
Contact members of the kind mentioned above are stamped out from a flat blank and a slit is stamped in the member. Since it is not possible to stamp out narrower slits at about 0.6 mm, because the punch will break when it is used in production, the slit obtained is still too wide to give sure contact against wires with a conductor diameter of 0.4-0.7 mm. To remedy this, and to obtain a narrow slit such that the contact member cuts through the insulation and gives a gas-tight contact with the conductor, the material lying parallel to the slit in the contact region is stamped. The stamped impression is done with a punch which plastically deforms the edges of the slit towards each other. Above the slit the punch has a shallow upside-down V profile, which is defined by flat or somewhat outwardly curved surfaces substantially parallel to the working direction of the punch. The punch works against a flat die. For reliably controlling the slit width, there have also been attempts to use a die with a tongue that thrusts into the slit. Since the tongue is too small it is easily broken, however.
DISCLOSURE OF THE INVENTION
In manufacturing a contact member by stamping in the way given above, there will be problems in obtaining the required width and tolerance of the slit when the starting material varies in hardness and thickness. Since the member is only impressed from one side, the material is also only deformed on one side, resulting in that the slit becomes wedge-shaped, i.e. its edges on the impression side are closer to each other than on the opposing side. The contact surface against a conductor will thus be less than what is theoretically possible. All this means that the slit contact tips are given an uneven quality, and in certain extreme cases a gas-tight contact is not obtained.
One object of the present invention is to provide a contact member which does not have the above-mentioned disadvantages, by stamping the member in the region of contact such that the material at the edges of the slit deform plastically so that the right width and tolerance are obtained, and so that the side surfaces of the slit are parallel and have greater height in the thickness direction of the member than in the rest of the member.
Preferably, one leg of the member is stamped from one side and the other leg of the member from the other side.
Another object of the present invention is to provide a tool for stamping the contact region of the member such that the tool contains two punches, a first and a second punch working against each other, each of which has a projecting profile along the slit and a surface sloping in the transverse direction of the slit, this surface being defined by two parallel, flat surfaces in the working direction of the punch, a first of these surfaces together with the sloping surface forming an acute angle above one leg, in the case of the first punch, such as to plastically deform the material in the leg towards the slit during stamping, and of which the second flat surface together with a contiguous flat surface at right angles to the second flat surface forms a die towards the material in the other leg which is plastically deformed by t
REFERENCES:
patent: Re32898 (1989-04-01), Dechelette
patent: 3636500 (1972-01-01), Sedlacek
patent: 4671595 (1987-06-01), Pohl
Fransson Gunnar S.
Karlsson Karl O.
Westerlund Alf T.
Pirlot David L.
Telefonaktiebolaget L M Ericsson
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