GB766339A - Work holding apparatus for flash-butt welding machines - Google Patents

Abstract

766,339. Welding by pressure. TAYLORWINFIELD CORPORATION. March 8, 1954, No. 6633/54. Class 83 (4). In an electric flash butt welding machine having a work holder comprising a frame, a fixed die and a movable die there is provided a primary actuator to drive the movable die through its working and return strokes, a secondary actuator operable on the movable die at the end of its working stroke to urge the die towards the fixed die and a thrust transfer member to permit the transmission of load from the secondary actuator to the movable die, the transfer member being displaceable from an operative position preparatory to the return stroke of the movable die. On each platen of the welding machine a rigid framework is formed by members 10, 11, 14 to which the lower die 13 is attached. Small double-acting hydraulic actuators 21 are secured to members 10, 11 with their pistons supporting a carrier 16, formed by side walls 18, 19, front wall 17 and base 20, vertically slidable on the frame. The carrier is guided by rods 44 pivoted to the base 20 and to bell-cranks 41, 42 which are coupled by a rod 46 and pivoted to a web 43 forming part of the frame. The upper die 12 is secured to a deformable member 24 bolted to the base 20 of the carrier. The cylinders 28 of large singleacting hydraulic actuators 27 are secured to the member 24 through apertures in the base 20 and the rods 31 of the downwardly spring-urged pistons thereof extend upwardly. A rigid bar forming part of the frame extends above the actuators 27 and provides a guideway for a sliding bar 37, having downward projections 38, movable by a fluid pressure operated actuator 39 to position the projections 38 either immediately above the rods 31 or displaced therefrom. With the projections displaced from the rods 31 and with pressure in the lower ends of actuators 21 the carrier and die 12 are raised to permit strip to be positioned on the die 13. Pressure is then applied to the upper ends of actuators 21 to lower the carrier and die on to the strip. The bar 37 is then shifted to locate projections 38 above the rods 31 and pressure is applied to actuators 27. The rods 31 move into contact with the projections and the cylinders 28 are forced downwardly to clamp the strip. To release the strip after welding pressure is first relieved from actuators 27, bar 37 is shifted and pressure is then applied to lower ends of actuators 21.