GB763767A - Improved method and apparatus for the manufacture of fusible metal caps - Google Patents

Abstract

763,767. Making fusible caps for stud soldering; blank punching; stamping. SVENSKA AKTIEBOLAGET GASACCUMULATOR. Jan. 18, 1955 [May 14, 1954], No. 1459/55. Classes 83 (2) and 83 (4). [Also in Group XVIII] In making a fusible metal cap for frictionally fitting to the end of a metal stud &c. to be electric arc stud soldered, a circular disc of fusible metal is formed into a bowl having a cylindrical wall, flux is inserted into the bowl, a second smaller disc of fusible metal is fitted in the bowl to cover the flux and axial indents are formed in the wall to retain the second disc in position. In an embodiment a series of dies 10 are provided in a table 2 intermittently rotatable beneath a series of units A-G stationary parts of which are mounted on a base 1 and upper movable parts of which are mounted on a slide 4 which is vertically reciprocated when the table is stationary. The unit A comprises a die 6, Fig. 3, above one of the dies 10 in the table 2, having a guide 7 for the feed of a strip 8 of silver solder, copper solder (a copper phosphorus alloy) or welding bronze (copper zinc alloy with nickel lead or tin) and a punch 9 which on downward movement of the slide 4 to which it is attached cuts a circular disc from the strip and ejects it from the die 6 to fall into a cavity 13 in the die 10. The table is moved one step to locate the die 10 beneath unit B which comprises a spring- pressed member 16, Fig. 4, to hold the disc in the die 10 while a punch 15 engages the disc to form it into a bowl 17 with a cylindrical wall, the member 16 and punch 15 being attached to slide 4. The table is moved another step and the bowl is located beneath the unit C which includes means for delivering a measured quantity of alkaline metal chloride, fluoride or borate flux into the bowl. With the bowl beneath unit D which is similar to unit A a disc of fusible metal is punched from a strip to fall into the bowl to cover the flux. In the next position beneath the unit E a punch presses the second disc into the bowl. A further table movement brings the bowl beneath the unit F where a punch 31, Fig. 8, attached to the slide 4 forces the bowl through the lower part of the die 10 provided with axial ridges to corrugate the cylindrical wall and ejects the cap from the table. A unit G comprises a brush 34 for cleaning the bore of the die 10. In a modification the table may be replaced by an endless conveyer belt. Instead of corrugating the cylindrical wall, three single spaced indents may be provided. The finished cap, Fig. 8a, is fitted to a stud and retained thereon by frictional engagement of the corrugations on the stud.