US Patent 7836817 Fluid pressure cylinder

A pair of recesses is formed on a cylinder hole of a cylinder tube, wherein the recesses are recessed further into the cylinder hole from an inner circumferential surface thereof. Projections that correspond to the recesses are disposed on a head cover and a rod cover, respectively, which are installed into both ends of the cylinder tube. The head cover and the rod cover that are accommodated in the cylinder hole are positioned through abutment of the projections against stepped portions of the recesses.