Importance

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Abstract

A telescoping workover rig is characterized by a derrick having a bottom mast section mounted on a base or carrier and a top mast section telescopically fitted in the bottom mast section. In functional configuration a system of tram sheaves mounted on movable trams and connected to opposite fixed stationary sheaves by a continuous cable, serve to raise and lower a travelling block suspended by the cable from travelling block sheaves and crown sheaves in the extended top mast section. The trams that mount the tram sheaves are fitted to the ends of one or a pair of cylinder rods extending from a corresponding tram drive cylinder or cylinders. This arrangement facilitates hydraulic extension and retraction of the cylinder rod or rods, corresponding movement of the trams and tram sheaves and extending and shortening of the loops of the cable wound on the tram sheaves and stationary sheaves, as well as the crown sheaves and travelling block sheaves, to control raising and lowering of the traveling block suspended in the derrick. A lifting cylinder or cylinders are mounted on the carrier and each lifting cylinder has a cylinder rod connected to the derrick for raising and lowering the derrick. A scoping cylinder is provided on the bottom mast section and uses a scoping cylinder cable connected to the top mast section to raise and lower the top mast section telescopically with respect to the bottom mast section.

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First Claim