| 摘要 |
A transmission (26) for reducing the pulley ratio between a drive shaft (42) and a transmission shaft (66) is disclosed. The transmission (26) is adapted to convert a higher speed rotary motion to a lower speed linear motion. The transmission (26) has two pulleys (30, 32) rigidly mounted together on a shaft (66) and the pulleys (30, 32) have a different number of teeth. A pair of belts (36, 38) are mounted on the drive shaft (42) and a transmission shaft (66) engages a pulley (32) on the top (86) of a first transmission pulley (32) and another on the bottom (84) of a second transmission pulley (30). When the drive shaft (42) imparts motion to the belts (36, 38), the belts (36, 38) move the transmission between the drive shaft (42) and the follower shaft (44). By arresting the movement of one of the belts (36, 38) by a clutch/brake (140), the transmission (26) can be converted into a two speed transmission. If the belts (36, 38) are independently driven, one each by two motors (150, 154), the transmission (26) becomes operable in an infinite number of pulley ratios. One particular application for this pulley transmission (26) is in a carriage drive system for a Coordinate Measuring Machine. |
