| 摘要 |
<p>A cable tensioning device 10 comprises a cylinder 11 and a piston 12 slidably mounted in the cylinder with its rod 13 extending through one end. Each of the cylinder 11 and the rod 13 are provided with cable anchors 14 at their outer ends. The piston and cylinder define two oil compartments 17, 18, the first of which extends into the hollow piston rod 13 so that oil within the compartment can act on a slidable wall 21 to compress gas in a reservoir 22. Flowpaths 24, 25 exist between the two compartments; the upper path 24 contains a pressure relief valve allowing flow from the second compartment 18 to the first compartment 17, whilst the lower fluid path 25 has a non-return valve allowing flow in the reverse direction. The external application of tension to the cable causes extension of the device and compression of the gas in the chamber 22, so that when the tension is released the gas contracts the device restoring tension in the cable. The pressure relief valve prevents an instantaneous reaction from the device with the result that there is a dead band preventing an oscillatory condition being set up.</p> |
