Effective, low-cost torque limiting drive

摘要

A drive linkage has internal shaft (1) having a bump (3) and an external shaft (11) having an open center and a bump (15) extending into the opening. The bumps are aligned and meet at surfaces having an angle with an outward component and a lateral component. In normal operation shaft (11) is rotated by the lateral component of force from bump (3). If the driven element will not move, then the outward component of force from bump (3) forces shaft (11) outward to allow bump (3) to move past bump (15). (Alternatively shaft 11 or both shaft 11 and shaft 1 may flex.) This prevents damage to the drive linkage or at an element being driven. The drive linkage is undamaged and simply continues to attempt to drive as described. The two shafts with bumps each may be inexpensively molded as one piece.