| 摘要 |
A direction setting device has a frame and a rotatably mounted shaft which supports a first belt pulley whose rotational position defines a direction to be set. A rotary motor on the frame supports a second belt pulley, and an endless belt extends around the first and second pulleys. A deflecting device deflects a second part of the belt while the motor is stationary at a set position of rotation, so as to change the effective length of the second part of the belt. A resilient tensioning device changes the length of the a first part of the belt to compensate for the change in length of the second part of the belt. This enables the first pulley to be turned through an angle that is dependent on the deflection of the second part of the belt by the deflecting device. |
