Chain welding machine

摘要

This disclosure relates to a chain welding machine for the electric resistance pressure butt welding of a length of chain having interlinked chain links pre-bent into a C-shape. The machine comprises a pair of oppositely movable upsetting tools for engaging the opposite rounded ends of a chain link to be welded. A drive train is provided for each upsetting tool and one of the drive trains includes as an element thereof a single acting hydraulic cylinder. A hydraulic system for activating the cylinder includes a hydraulic pump connected via a feed line with the cylinder through a control valve, pressure regulating valve and check valve. The check valve is arranged to block flow of hydraulic fluid from the cylinder during a portion of the upsetting stroke of the machine and is unblocked by the control valve after termination of a welding cycle.