DE857251C - Process for the production of electrical contacts with precious metal inlay or overlay - Google Patents

Description

Process for the production of electrical contacts with precious metal or pad The invention relates to a method for producing electrical Contacts, such as contact clips, contact bridges, contact levers and the like, for electrical Contacting objects whose contact carriers are made of copper, bronze or Brass, more rarely made of iron or aluminum or iron or aluminum alloys exist and have welded-in or welded-on contact tracks made of precious metal.

To obtain the known contacts of this type, a block shape is used of square, rectangular or round cross-section of the contact carrier metal went out. Depending on the number of desired contact tracks are in the raw block one or more grooves planed or milled into which the contact tracks made of precious metal soldered in or welded in and the block is then profiled into sheet metal, strip or simply Bars rolled out or drawn. These are used to manufacture the finished Contacts required strips cut off and bent into the desired shape.

This known production method has the disadvantage that it is only for Contacts can be used that have a simple, in particular uniformly strong cross-sectional shape exhibit. On the other hand, if the latter is a complex one, especially one with material thicknesses that differ significantly from one another, as z. B. occur in contact levers with pivot eyes, so must be according to the known Process so many rolling or drawing stages are used that the process becomes inefficient. The invention gives a possibility of such profiles on substantially more economical way to manufacture.

The new method consists in that initially a semi-finished product with partially or everywhere with respect to the finished contact enlarged cross-sectional dimensions obtained by extrusion from the carrier material, then onto this semi-finished product one or more contact tracks made of precious metal welded or welded on or or soldered on, whereupon rolling and / or pulling up to the finished size of the Cross-section and the transverse division of the strand takes place.

The degree of enlargement of the cross section produced during extrusion opposite to. that of the finished product can be according to the length and thickness of the cross-section to be different. With a narrow cross-section, one or more thickenings has, it is z. B. attached, with the increase in thickness up to about to go on the i l / zfaclie of the finished product while regarding the length the cross-sectional shape no or no significant enlargement for the purpose of the following Rolling or drawing is required.

If the contact track is to be welded or soldered into a groove, so the latter can be produced at the same time during extrusion.

The new method can also be used when the contact track consists of a base metal instead of precious metal, which has better contact properties has than the base metal of the contact carrier, or if the contact track is on a fine bar or rib of the contact carrier, which is attached during extrusion Would cause difficulties, and therefore only after extrusion z. B. by welding in a: Groove attached to the semi-finished product and then with this rolled or drawn together.

The new method is explained in the drawing using three different contact forms, for example. Fig. I and 2 or 3 and 4 or 5 and 6 show three different semi-finished product forms obtained by extrusion in an isometric representation, each without and with a contact track welded in or on. Contact tracks, Fig. 7, 8 and 9, the three different strands after rolling and / or drawing to the finished size, also in an isometric view, Fig. IO, II or 12, 13 or 14, 15 each a side view and top view of the finished Contacts. The semifinished product of the first embodiment (Fig. I) obtained by Dick's extrusion process is intended for a movable two-armed contact lever 2 (Fig. Ib and ii) that can be pivoted about the bearing eye i. With regard to its thickness, the cross-section of this semifinished product has great differences, which is due to the arrangement of the bearing eye i. In order to ensure a clean rolling down and / or pulling of this strand to the exact cross-sectional dimension of the contact (Fig. 10 and ii), the cross-section of the semi-finished product (Fig Pull on the strand obtained (Fig.7) or the finished contact. The groove 3, which is used to insert and weld in the contact track 4, can be attached during extrusion or specially planed or milled. After the contact track 4 has been welded in or soldered in (Fig. 2), the whole thing is rolled down to its finished size and / or drawn. The thickness of the cross-section loses relatively more than its length, which is hardly noticeably smaller. The contacts 2 are separated from the finished, profiled strand (Fig. 7) by dividing it transversely, after which the final machining is carried out by drilling the holes 1, 5, etc.

Already from the explanation of the manufacture of this exemplary embodiment it can be seen that the new process is distinguished by its simplicity and cheapness without the cross-sectional shape are significantly taken into account must, and that it is also particularly suitable for the production of large quantities.

The production of a contact with two welded-on contact tracks 6 is shown, for example , in FIGS. 3, 1, 8, 12 and 3. The thickness dimensions of the cross-section of the extruded semi-finished product (Fig. 3 and 4) are again considerably greater than those of the rolled or fully drawn strand (Fig. 8). The contact tracks 6 are also welded on between the extrusion process and the rolling or drawing process.

In the manufacture of the third illustrated in Figs. 5, 6, 9, 14 and 15 Exemplary embodiment, the arrangement of a contact track 7 is shown, which is not directly on the extruded contact carrier 8, but on a strip-like or rail-like Intermediate carrier 9 is welded or soldered, which in turn is then in a groove io of the semi-finished product 8 (Fig. 5) welded or soldered and then together the latter is rolled and / or drawn to the finished size (Fig.9). Last follows Again the dismantling of the strand according to Fig. 7 into the individual contacts (Fig. 14 and 15) by cutting across.

The new process offers: compared to known processes in which the contact pads are soldered onto the finished profiles or profile sections, the large and decisive in many areas of electrical engineering Advantage that the contact pad by the deformation during rolling and / or pulling undergoes significant compaction, consolidation and hardening.

Claims (1)

PATENT CLAIMS: i. Process for making electrical contacts, those from a contact carrier with There are precious metals in or out, characterized in that initially a semi-finished product with partially or everywhere opposite the finished contact from enlarged cross-sectional dimensions by extrusion obtained from the carrier material, then one or more contact tracks on this semi-finished product made of precious metal are welded in or welded on or soldered in or on, whereupon rollers and / or pulling up to the finished size of the cross-section and the transverse division of the Strand takes place. a. Method according to claim t, characterized in that the enlargement the cross-sectional dimensions during extrusion according to the length and thickness of the cross-section is different and takes place in particular with regard to the thickness of the cross section. 3. The method according to claim r, characterized in that the contact track on a special intermediate carrier arranged and the latter like a contact track itself is welded or soldered on or welded to the extruded semi-finished product.