Abstract: The device features the elimination of bending moments in all members to ow a design of minimal weight, and depends on the use of an existing structure to provide stabilizing reactions when erected. A rigid mast is pivoted at its lower end on the existing structure, and supports a block and tackle at its upper end. A rigid triangular spreader and cable assemblies support the mast.

Abstract: A two-way horizontally extendable trolley 22 comprising a trolley frame 51 and wheels 52 for supporting trolley frame 51, a first horizontally elongated trailer frame 54 slidably mounted on frame 51, and a second horizontally elongated trailer frame 55 slidably mounted on trolley frame 51, said trailer frames 54 and 55 each having a first end extending beyond an end of frame 51, and auxiliary wheels 56 and 57, respectively, for supporting said first ends. Trolley 22 includes: means for horizontally extending trailer frames 54 and 55 outwardly from the trolley frame 51 and retracting trailer frames 54 and 55 inwardly toward trolley frame 51; hoisting means mounted on trolley frame 51; auxiliary hoisting means mounted on trailer frames 54 and 55; and means for driving wheels 52. Crane 10 for use with trolley 22 is also disclosed.

Abstract: A support for boom end sheaves for lifting and/or handling machines, carrying at least a first sheave which receives a flexible rope, particularly a lifting cable, extending from the boom, is characterized in that it carries a pulley-block mounted on a lever which is swingingly carried by the support.

Abstract: As part of a well derrick system using pair of elongated hydraulic cylinders mounted on the derrick face for well pipe elevating, in which an equalizer beam bridges the cylinder ram heads to maintain equality of advance of the rams, the beam being pivoted on a horizontal pivot above the ram heads, the beam carries a lower centrally aligned horizontal pivot sheave means from which cable means extend downwardly to suspend a travelling beam from which depend any of various pipe manipulating tools. In some species additional sheave means on the travelling beam and on an intermediate fixed beam provide for multiple wrappings of the cable means whereby force or distance multiplication may be obtained.

Abstract: A new and improved portable hydraulic rig for performing workover, drilling or other operations on a well, usually a petroleum well, wherein the rig has a telescoping mast for telescoping to a reduced length for transportation, wherein the mast is cantilevered in use so that the travelling block moves vertically at one side of the mast, wherein the cable for the travelling block is reeved over the various sheaves including a sheaves on a hydraulic power assembly with the dead end of the line being fastened at or in proximity to the rig floor for balanced loading on the legs of the mast and to enable slack in the cables to be taken up when telescoping the mast.

Abstract: A self-contained tensioning device for adjusting the tension of a backstay cooperates with a bridle which connects the backstay to the transom of a sailboat. The device includes a pair of plates having sheaves rotatably mounted between the plates to form a passageway for the bridle cables and a block and tackle for adjusting the plates and sheaves along the bridle cables relative to the transom. By varying the position of the plates and sheaves along the bridle, the spacing between the bridle cables is decreased or increased and the tension in the backstay is adjusted.