| 摘要 |
<p>The pivot frame (1A, 1B) consists of a right-hand side beam (2A), a left-hand side beam (2B), front beam (3A), rear beam (3B) and pivot devices (4A, 4B). The trolley frame is made of two half-frames (1A, 1B) each of which is usually L-shaped.</p> |
