Patent ID: 8274864

Claim:
A slip gear structure comprising: a gear main body portion in the form of an annular plate having along the outer periphery thereof tooth portions constituting a gear, there being provided a pair of spring portions between peripheral walls of an inner opening of the annular plate so as to extend across the opening and to be arranged side by side so as to be opposed to each other; and a positioning member equipped with a small diameter plate-like portion having a central hole with which a shaft is rotatably fit-engaged and a pair of support wall portions arranged on both sides of the central hole and protruding from one surface of the plate-like portion, wherein when the slip gear structure is in a non-fit-engaged state with respect to the shaft, the spring portions of the gear main body assume a state in which they are elastically pressed against corresponding side edge portions of the pair of support wall portions of the positioning member, with central spring portions thereof situated between the corresponding side edge portions of the pair of support wall portions protruding into the central hole; and when the slip gear structure is in a fit-engaged state with respect to the shaft at the central hole, the central spring portions of the spring portions of the gear main body portion are elastically pressed against the shaft for slip engagement with the shaft.