An adjustable hinge mount for a seat having an adjustable seat back comprises an axle interconnecting first and second hinge members for pivotal motion relative to each other, an internal teeth formed in the second hinge member, a bearing plate having teeth for locking cooperation with the internal teeth, spaced guide walls formed in the first hinge member for guiding the bearing plate in reciprocal directions, and an control arrangement for controlling motion of the bearing plate into and out of engagement with the internal teeth. The control arrangement includes a lever and a cam in unitary motion with the lever for cooperation with the bearing plate. The cam is mounted to the first hinge member for pivotal motion about a cam axis located at a position spaced from an axis of the axle.