| 摘要 |
A swinging boom apparatus comprises a frame 1, a boom or boom carrier 2 rotatably mounted on the frame 1, a guide plate 3 rotatably mounted on an axle 8 fixed to the frame 1, means 4, 5 for rotating the guide plate 3 and a gear 6 attached to the boom or boom carrier 2 and meshing with a toothed rim 7 within an aperture in the guide plate. The boom may thus be turned over 180 DEG in either direction from the position shown. <IMAGE> |
