| 摘要 |
<p>The invention comprises a first arm member 2 and a second arm member 3 flexibly coupled mutually by a ball joint 4. From a plurality of through-holes 5 provided in the first arm member 2 to a plurality of holding holes 6 provided in the second arm member 3, compression coil springs 8 are inserted. Support shafts 10 are inserted, movably back and forth freely, in the through-holes 5 behind the rear end portion of the compression coil springs 8. A certain support shaft 10 is moved forward by actuator or the like to push the compression coil spring 8 while other support shaft 10 are moved backward. As a result, the second arm member 3 can be moved to a specified position by the ball joint 4. Stopping state of the second arm member 3 at the specified position is maintained by the balance of position of support shaft 10 and repulsive force of compression coil spring 8.</p> |
