| 摘要 |
<p>The guardrail comprises four posts (2) connected by pantograph type extensible linkage. The hollow circular section posts each contain a coil spring (7) whose head is anchored by a diametric pin (8), and a chain of flat rectangular section (9,11,13) bars. The foot of the spring hooks onto the head (4) of the chain. The last bar (13) of the chain is 'L' shaped forming a post anchoring foot. By pulling the chain from the post and pivoting the foot horizontally about either pin (10,12) the length of the foot is varied. The hooked arm (13A) turns down to grip the edge of the road opening.</p> |
