Rack structure for backlash-free rack-and-pinion

摘要

To provide a backlash-free rack simple in structure and small in size, still assuring that no backlash is caused in reciprocating a movable part in an electronic device toy, or watch et al, the rack structure comprises first and second toothed bars (1, 8 and 2, 9 ) both integrally connected to each other by an intermediate joint (3, 11) made of a soft resin material to provide a linear toothed bar object. The linear toothed bar object is so folded about the intermediate joint that the first and second toothed bars are somewhat staggered and laid on each other with their teeth out of phase, thereby preventing the backlash which otherwise, would be caused between the teeth of the rack and those of the pinion.