| 摘要 |
A drive system comprises an expander assembly for possibly use with a tractor is arranged around and attached to a rotor casing. The assembly comprises a mandrel (shaft) having first and second opposing threaded portions 691, 692 arranged coaxially. Each threaded portion 691, 692 is housed in an expander follower. In use, the mandrel rotates in a first sense and the first and second expander followers are driven apart one from another. When the mandrel rotates in the opposite sense the first and second expander followers are driven towards one another. |
