US Patent 12121153 Hinge and electric bed using the same

A hinge includes identical first and second members each having a base portion with an end surface, a long arm with a pivot hole and a middle abutment surface and a short arm with a rear abutment surface both extending from the end surface, and a protrusion at a distal end of the long arm. Each protrusion has a front abutment. A pivot is inserted through the pivot holes to couple the first and second members in a way that the hinge is limited in a range of pivotal angle.