Highfield lever Highfield lever A Highfield lever is a lever device which allows tension to be rapidly set up in a wire and equally rapidly released to the required extent. It is frequently used in sailing boats where tension in some part of the rigging needs to be adjusted to a pre-set amount as the wind impinges on one side of the sails or the other. It is typically used in running backstays (runners). To make it work, the backstay is led through a block or fairlead along the deck to a two-legged, second order lever mounted with its fulcrum above deck
Lever frame required to move them. Mechanical lever frames and interlocking have now largely been replaced by modern, much larger electrical or electronic route interlockings located in Power Signal Boxes and more recently Integrated Electronic Control Centres which are able to control much larger areas of the rail network. A mechanical lever frame is designed to harness mechanical advantage to operate switch points, signals or both under the protection of the interlocking logic. The levers are connected to field appliances via solid pipes or taut wires such that the full travel of the lever will reliably cause full travel in the appliance.