| 摘要 |
<p>The metal walls of the vehicle, or trailer, have vertical grooves and ridges pressed into them for strength. The ridges have pointed profiles extending outwards. The roof shaped profiles can be in two stages for added strength. The ends of the ridges are contoured into circular or spherical shapes to provide a good finish. The ridges are simple to press in one operation and do not exceed the tensile strength of the metal during pressing. They do not mar the appearance of the walls.</p> |
