| 摘要 |
<p>The main girder for a gantry crane is of closed box-section and has a centrally mounted travel rail. The girder is of trapezoidal section, widening towards the underside, and comprises two trapezoidal compartments (1, 2), one above the other. The top one is preferably of lower height than the bottom one, and the lines extending the sides of the trapezium may intersect at a point (4) near the top face of the rail (3). In the middle of the top compartment may be mounted a I-section, whose upper strip may bound the top of the trapezoidal section.</p> |
