High-Speed Welder for Crossbar Switch Contacts

A novel-design welding machine has been constructed to attach the precious-metal contacts required on the switch springs of the crossbar-type telephone central office equipments. Parts are carried through the various checking stations and the multiple welding nest by a geneva-driven high-speed transfer mechanism. The electronic weld control is a 20-unit modular minimum-size packaged capacitor discharge welder utilizing circuits designed to provide a high degree of reliability with semiskilled electrical maintenance. Carded units of ten switch springs are transferred through the welding nest where 20 contacts are fed, welded, clipped, and checked on a 3/4-second cycle. The speed of 100,000 welds per hour permits this machine to replace 20 previous machine units, thus realizing large manufacturing-cost reduction.