| 摘要 |
The vertical supports (10) for a travelling framework or structure are each carried by a base frame (14) mountedon four castor wheels (12), one at each corner. To enable the structure to travel over eneven ground and hence to enable any castor wheel to be lifted higher than the others, the base frame forms an adjustable linkage. The bottom of the vertical support is carried by a base with four side members and a point higher up has a similar frame with four side members (32 to 34) clamped around the sides of the vertical. The lower frame is supported by arms (18) extending radially and horizontally outwards, connecting it to a larger square frame at the same level, to which the wheels are attached. |
