Adjustable ring-shaped spring clamp - for holding pipe ends together for welding, avoids uneven stressing and distortion

The ring has a rectangular cross section which tapers gradually from the thickest portion at the top to the thinnest portion at the bottom where it is split. The split ends have eye-holes in which are bolts which may be drawn together or sepd. by a double-acting pneumatic cylinder. The ring is made of Al or plastics with a metal insert, and must have enough spring in the unloaded condition to allow it to be placed by hand over the end of the first pipe. Hydraulically operated radial stops round the ring are used to posn. the two pipes and then withdrawn so that one can be pushed up against the other, in which posn. the clamping mechanism is operated to hold them firmly together. Spot welds can then be made through apertures at intervals round the ring. The clamp is light to handle and distributes the stresses evenly round the pipes being held.