An apparatus can include a processor; memory accessible by the processor; a first housing that includes a first link end; a second housing that includes a second link end; and a hinge assembly that includes a first link coupled to the first link end via a first axle, a second link coupled to the second link end via a second axle and an intermediate axle that operatively couples the first link and the second link where stop surfaces of the first and second links define a minimum radius of curvature of the hinge assembly.