| 摘要 |
A sign (10) includes a gear subassembly (50, 52) and a slip assembly (74, 80) operatively associated between the drive shaft (42) and the output shaft (46) of one of the display elements (14). During the portion of a rotation of ther input gear teeth (72) engage the output gear teeth (78). During another portion, the input gear teeth (72) disengaged. At least one partial gear tooth (82a, 82b) assist in periodically aligning the gear teeth. The slip subassembly comprises: an input slip element (74) defining generally arcuate line about the axis of the input slip element; and an output slip element (80) defining a generally straight line that is non-intersecting with an extends perpendicular to the input slip axis. During a portion of a rotation of the input slip element (74), the arcuate line and the staright line of the slip elements (74, 80) are slipping contact to prevent the output slip element (80) from rotating. During another portion of the rotation, the output slip (80) can be rotated. The slip subassembly has a radius at least a large as the radius of the gear teeth (72, 78). |
