Gas shield chamber for arc welding of rails

Abstract From the Canadian patent

A gas shield chamber for enclosing a welding joint of a pair of rails during the arc welding of the welding joint. A Pair of side backing plates are each held in contact with the groove at one side of the rails within the chamber and the side backing plates are respectively movable independently of each other by a pair of drives having manual-powered operation change-over means. The ratio of respective flow rates of each shielding gas from respective injectors into the chamber is varied in accordance with the movement of the side backing plates. A pair of ground terminals of a welding power source are arranged on the sides of the rails.