Lever resistance (or load). It is common to call the input force "the effort" and the output force "the load" or "the resistance." This allows the identification of three classes of levers by the relative locations of the fulcrum, the resistance and the effort: These cases are described by the mnemonic "fre 123" where the fulcrum is in the middle for the 1st class lever, the "r"esistance is in the middle for the 2nd class lever, and the effort is in the middle for the 3rd class lever. The lever is a movable bar that pivots on a fulcrum attached to
Highfield lever about 1930. http://www.ybw.com/cb/gloss.html#Highfield https://books.google.com/books?id=Fp63wWByImQC&pg=PA145&lpg=PA145&dq=%22Highfield+lever%22&source=web&ots=dtOvGn79kw&sig=vDH04nBiAXxluXvIdcGcUdh3i_U&hl=en&sa=X&oi=book_result&resnum=3&ct=result 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