Electrical connectors – Metallic connector or contact having part permanently...
Reexamination Certificate
1999-05-12
2001-09-11
Sircus, Brian (Department: 2839)
Electrical connectors
Metallic connector or contact having part permanently...
C439S884000
Reexamination Certificate
active
06287158
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a contact element having a contacting region and an attachment region for an electrical conductor, the attachment region having a reduced material thickness as compared to the contacting region and being configured integrally with the contacting region.
BACKGROUND INFORMATION
Contact elements configured as flat connectors are known, the contacting region being configured as a flat plug-in element for insertion into a socket, and the attachment region being configured for welding on an electrical conductor, cable, or the like. The attachment region has a lesser material thickness than the contacting region. For this purpose, the plate material is reduced to a lesser material thickness by milling or pressing. The reduction in material thickness decreases the forces that are necessary in order to bend the material when the electrical conductor or cable is secured, this reduction allows the welding current flow to be modified or optimized.
SUMMARY OF THE INVENTION
It is an object of the present invention to create homogeneous geometrical conditions for positioning and welding an electrical conductor onto the contact element, without thereby requiring a time-consuming and costly milling operation.
According to the present invention, the contacting region has at least two sheet-metal parts, lying against one another, of a folded sheet-metal blank; and at least a portion of the sheet-metal blank is elongated and deformed in order to form the attachment region.
According to the present invention, it has been recognized that a homogeneous geometrical configuration of the contact element for positioning of an electrical conductor, for example a contact wire, for the subsequent welding operation is possible even without the use of time-consuming and costly milling machines. Instead of reducing the material thickness of the sheet-metal blank in the attachment region, according to the present invention the material thickness of the sheet-metal blank is selected in accordance with the desired reduced material thickness in the attachment region. The different material thicknesses are then produced by folding over the sheet-metal blank once or several times in the contacting region. The contact element according to the present invention can be used as a plug-in or screw-in contact, and is soldered or welded to an electrical conductor in the attachment region. Press-folding of the sheet-metal blank is associated with less material loss and lower tool costs as compared with conventional methods. The contact element according to the present invention can moreover be manufactured with much less expenditure of time.
A one-piece sheet-metal blank with a desired geometry is punched or separated out from a piece of metal plate made of conductive material. Since the geometrical requirements for the sheet-metal blank are defined even before processing, material wastage during manufacture of the contact element can be minimized, for example with the use of computers.
In a first embodiment of the present invention, a cutout is formed in the sheet-metal blank between the contacting region and the attachment region. The cutout on the one hand facilitates the independent geometrical shaping, i.e. folding or press-folding of the sheet-metal blank to form the contacting region and attachment region. The cutout in the transition region can be produced in accordance with the desired application. Depending on the configuration of the cutout, an unequivocal energy expenditure can be defined for the operation of compressing or folding over the sheet-metal blank, and an exactly predetermined welding operation can thereby be performed. The cutout moreover results in a reduction in cross section in the transition region between the attachment region and the contacting region, thus achieving a lower welding current flow in the transition region. The welding procedure during attachment of the electrical conductor to the contact element can thus be additionally controllable. The electrical conductor is preferably a metal wire.
The contacting region is preferably embodied as two sheet-metal parts of the sheet-metal blank, folded or pressed-folded parallel to one another. It is thereby possible, advantageously, to create in the contacting region a plug-in tongue with two, three, or many times the material thickness of the sheet-metal blank. Press-folding or folding also makes it possible, however, to produce a plug-in tongue with different cross sections, for example a triangular cross section.
In another advantageous embodiment of the present invention, the attachment region has a folded sheet-metal part whose two limbs surround the electrical conductor in clamping fashion. The electrical conductor is thereby fastened to the contact element, and can thereafter easily be mechanically welded.
To prevent problems with the welding operation for thick electrical conductors, the complete contact element can be press-folded at one bending edge, such that in the contacting region the folded sheet-metal parts lie parallel next to one another, and in the attachment region the two limbs splay apart from one another to receive the electrical conductor. The electrical conductor can be fastened in the attachment region of the contact element by way of a pressing or stamping operation. In a particularly preferred embodiment of the present invention, the attachment region has two sheet-metal parts, joined to one another only via the contacting region, for grasping the electrical conductor, e.g. a contact wire. For this purpose, the attachment region has two separate sheet-metal parts which are each joined to the contacting region via webs formed by the cutout in the transition region. The two sheet-metal parts can lie with a small spacing opposite one another by folding the sheet-metal blank of the contact element, and can have on one side at least one lobe which is raised and forms a stop for the electrical conductor.
The sheet-metal parts of the attachment region either can be configured flat and parallel to one another, or can be embodied in bent fashion in the form of a clamp to receive the electrical conductor.
Preferably, at least one sheet-metal part of the attachment region has an impression to form a clamp receptacle. The impression creates, for example, a depression in the sheet-metal part, which enhances the clamping effect in the attachment region in this region. The impression can also serve, however, to position the welding punch at a predefined point in the attachment region. By way of a pre-impression operation, the wire cross section of the electrical conductor and the material thickness of the contact tongue in the contacting region can be matched to one another, and configured in the manner of a “projection weld.”
In the attachment region, two lateral stops can facilitate axial introduction of the electrical conductor into the attachment region, and prevent lateral shifting or slippage of the electrical conductor out of the attachment region. It is also possible, however, to provide only one lateral stop in order to allow lateral introduction of the electrical conductor into the attachment region.
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Kenyon & Kenyon
Robert & Bosch GmbH
Sircus Brian
Webb Brian S.
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