| 摘要 |
A trailer hitch includes an inner tube and an outer tube which can extend guided by support rollers. A spring pin locates the tubes at retracted and extended positions. A sprocket rolls on the bottom of the inner tube and is supported on the outer tube for rotation by a hand crank. The bottom surface of the inner tube has a series of holes by which the sprocket drives the extension/retraction movement. The roller and the sprocket are carried on plates clamped to the outer tube.
|
