Importance

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Abstract

Flash-butt welder in which the piston rod of a pneumatic cylinder is connected to one end of a pivotable lever arm. A pneumatic system sequentially supplies air at two different pressures to the cylinder. Fixed and movable platens, each with a work piece clamping jaw, are fitted onto a unitary shaft which is mounted in laterally spaced and generally parallel relationship with the pneumatic cylinder. The movable platen is moved by the opposite end of the lever arm along the shaft toward the fixed platen. The movable platen includes a laterally extending arm portion for angular orientation of the platen on the shaft. A switch is disposed to be actuated by the lever arm as it advances to a predetermined position which energizes a solenoid valve to supply substantially higher pressure air to the cylinder. An hydraulic cylinder, disposed in spaced parallel relation to the shaft, includes a piston rod engaged with a pivotable linkage carried by the arm portion of the movable platen. The hydraulic cylinder controls the speed of movement of the movable platen toward the fixed platen during flash welding of the work piece. A pivotable latch mechanism is disposed for releasably retaining the linkage in a fixed angular position and to release the same so that the controlling effect of the hydraulic cylinder is released from the movable platen. An adjustable release pin is disposed to pivot the latch mechanism to release the linkage so that the hydraulic cylinder no longer controls the advance of the movable platen during the upset phase of the welding cycle.

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First Claim