GB415221A - Improvements in or relating to methods of uniting metal articles by fusion and resulting products such as electric contact assemblies - Google Patents

Abstract

415,221. Brazing electric contacts &c. LAISE, C. A., Tenafly, New Jersey, U.S.A. May 13, 1933, No. 13974. Convention date, March 25. [Classes 83 (ii) and 83 (iv).] In brazing interengaging male and female members, such as electric contacts, the side faces of one or both of the members is or are provided with depressions so as to form capillary passages into which brazing material, placed at the end faces of the members, seeps when melted. One of the members is formed with a shank which is a press fit in the depression in the other member. The members may be of circular, hexagonal, square &c. section. Electric contacts of refractory metal such as tungsten or molybdenum or their alloys, or of precious metals such as platinum or iridium or other alloys are thus brazed on to their base metal supports. The contact 3 may be formed with a fluted shank 5, assembled as a force fit in a recessed support 2 containing a wafer 8 of brazing material such as copper. The parts may be placed in trays of nickel &c. and heated in a hydrogen atmosphere in a furnace to the melting point of the brazing material. Such an assembly may consist of a contact brazed into a threaded stud or into a sheet metal arm. In other forms, the support may have the fluted shank and the contact the recess, or the recess may be fluted instead of the shank, or both may be fluted. In a further form, Fig. 7, the part 3 may have a hollow shank 9, externally and preferably also internally fluted, co-operating with an annular groove 10 in the part 2, the projection 11, if desired, being also fluted. Brazing material 8 is inserted in the recesses. In order to economize in refractory metal or alloy, a base metal piece 22, Fig. 9, with two fluted shanks 21, 23 may be brazed respectively into the contact 19 and support 25. In a further form, Fig. 11, a facing 32 of refractory metal or alloy &c. is first brazed at 37 to a base metal part 33 provided with a plain or fluted shank which is then brazed into a fluted recess in the carrier 36. In this case the brazing material at 37 should have a higher melting point than the brazing material 31 in the recess 35. The brazing material may be applied to the end face of the male member instead of being separately placed in the recess. The refractory or precious metal contact may be made by heading or punching at a red heat in moulds or dies so as to form a rivet with a fluted or plain shank or a contact with a recess.