Abstract: A back-up clamp component for use in a back-up clamp and adapted to fit with other sections of the back up clamp, the component carrying a number of shoes which can be moved radially inwardly and outwardly, each shoe being connected to a respective piston and cylinder arrangement, each piston having a first side and a second side, first means permitting pressurised fluid to be introduced to the first side of a piston and second means permitting pressurised fluid to be introduced to the second side of a piston so that the shoes can be positively driven outwardly and inwardly, the first means and the second means including respective first and second conduits within the body, which conduits open at an end face of the component.

Abstract: A back-up clamp suitable for backing up a weld to be formed between adjacent pipe lengths in a pipeline, the clamp having a rigid clamp body, at least one set of clamping members mounted upon the clamp body, a set of back-up shoes mounted upon the clamp body, the set of clamping members and the set of back-up shoes being movable relative to the body, movement of the set of clamping members and the set of back-up shoes being controlled by fluid pressure applied to at least one location of the clamp, the clamp having a number of conduits adapted to deliver pressurised fluid to the location(s), all of each conduit being located within the body. The invention permits the provision of a back-up clamp which requires no flexible or external fluid hoses, and permits the manufacture of a back-up clamp suitable for use with small-diameter pipelines.