Abstract: The invention provides a pipe coupling configured for coupling pipes over a range of diameters including a gripping and sealing assembly comprising a ring of circumferentially linked carrier members (1) the circumferentially discontinuous members are interlinked by means of a tongue and groove connection between a groove (2) on a first member and a tongue (3) on an adjacent member, the opening of the groove which receives the tongue facing in a plane not in alignment with a tangent of the circumferential plane of the carrier and each tongue is attached to its member by a resiliency deformable arm whereby to provide stability of the circumferential links in the absence of any additional support.

Abstract: A multi-section telescopic jib or boom comprising a base section and three movable sections mounted to extend or retract relative to each other on operation of drive means within the sections, including a first ram connected between the base section and the innermost sections, a second ram connected between the innermost and central sections and a chain having ends connected between the innermost section or the first ram and engaging a chain wheel mounted on the central section or second ram, means being provided to releasably connect the chain to the outermost section to extend the boom.

Abstract: A multi-section telescopic jib or boom comprising a base section and three movable sections mounted to extend or retract relative to each other on operation of drive means within the sections, including a first ram connected between the base section and the innermost sections, a second ram connected between the innermost and central sections and a chain having .[.ends connected between the innermost section or the first ram.]. .Iadd.one end connected to the lowermost section or first ram and the other end connected to the innermost section .Iaddend.and engaging a chain wheel mounted on the central section or second ram, means being provided to releasably connect the chain to the outermost section to extend the boom.