Abstract: Concrete pumping conduits are connected by releasable hinged couplers. The ends of the conduits include metal pipes formed with annular grooves including a circular peripheral base and a stepped end wall immediate adjacent the end of the pipe to define a pair of generally parallel and radially extended, inclined sidewalls. The coupler is formed with inwardly projecting legs with the inner walls similarly stepped and defining a pair of generally inclined radial sidewalls offset in accordance with the offset of the grooved siewalls, but slightly less than such spacing. A sealing gasket is located within the base of the cup-shaped recess with a tongue-like ridge projecting between the two end faces of the pipe ends. The first radially outermost sidewalls of the coupler and the radially innermost sidewalls of the groove engage upon closing to provide a mechanical connection. The gasket is collapsed to seal the joints.