| 摘要 |
<p>The working platform is mounted on the end of a boom which pivots about a horizontal axis. The floor of the platform (8) forms a curve, convex towards the underside, so that with different angular positions of the boom (2) there is always a part of the floor which is horizontal, or the horizontal plane is tangental to the curve fo the floor. The floor can be a part-cylindrical surface with a horizontal axis, or it can be formed by two or more sides of a prism, whose edges are horizontal. The cylinder axis or prism edges can run at right angles to the boom centre line, and the platform can be fixed to the boom so that it cannot move in relation to it.</p> |
