Abstract: A pressure-operated valve is provided, particularly for use with a downhole pump of the fluid-driven, successive-stage, bladder type. Such a pump includes a plurality of pump and transfer modules. The pump modules have bladders which are operated by fluid, preferably gas, under pressure supplied through two separate internal passages in the modules to pump liquid upwardly through transfer modules. The pressure-operated valve is located below the bottom of the pump module and normally closes off the two gas passages. When gas under pressure above operating pressure is supplied through one of the passages, to establish a sufficient pressure differential between the passages, the valve opens to connect the passages. Heated gas can then be circulated to increase the temperature of internal oil passages extending through the modules to prevent paraffin formation. The two gas circuits can also be connected to enable removal of condensate.

Abstract: Fluid-operated apparatus is provided for handling and lifting loads of various weights. The apparatus includes a fluid-operated hoist with an elongate member extending therefrom to a load-carrying unit. A pilot fluid-controlled regulator supplies fluid to the hoist and a load-responsive, pilot fluid regulator is carried by the load-carrying unit and supplies pilot fluid to the pilot fluid-controlled regulator. The pilot fluid is varied according to the weight of a load so that the pressure of the fluid supplied to the hoist is accordingly varied by the pilot fluid-controlled regulator to automatically balance the load carried by the load-carrying unit. The load can also be lifted by bypassing the pilot fluid-controlled regulator and controlling flow of fluid to the hoist by a manually-adjustable flow control valve. The apparatus also can include a brake for preventing the elongate member from moving up or down while loads are being changed or are at rest.

Abstract: Fluid-operated apparatus is provided for handling and lifting loads of various weights. The apparatus includes a fluid-operated hoist with an elongate member extending therefrom to a load-carrying unit. A pilot fluid-controlled regulator supplies fluid to the hoist and a load-responsive, pilot fluid regulator is carried by the load-carrying unit and supplies pilot fluid to the pilot fluid-controlled regulator. The pilot fluid is varied according to the weight of a load so that the pressure of the fluid supplied to the hoist is accordingly varied by the pilot fluid-controlled regulator to automatically balance the load carried by the load-carrying unit. The load can also be lifted by bypassing the pilot fluid-controlled regulator and controlling flow of fluid to the hoist by a manually-adjustable flow control valve. The apparatus also can include a brake for preventing the elongate member from moving up or down while loads are being changed or are at rest.

Abstract: A fluid-operated, load-handling apparatus is provided for handling loads of various weights. The apparatus includes a fluid-operated hoist with an elongate member extending downwardly to a load-carrying unit. A pilot fluid-controlled regulator supplies fluid to the hoist and a load-responsive, pilot fluid regulator is carried by the load-carrying unit and supplies pilot fluid to the pilot fluid-controlled regulator. The pilot fluid is varied according to the weight of a load, being higher for heavier loads and lower for lighter loads so that the pressure of the fluid supplied to the hoist is accordingly varied by the pilot fluid-controlled regulator to automatically balance the load carried by the load-carrying unit. The apparatus also can include a brake for preventing the elongate member from moving up or down while loads are being changed or are at rest.

Abstract: A working pit with an articulated tool arm assembly is provided for an automobile assembly line. A tool carried by the arm assembly is used to perform assembly operations in an automobile moving either longitudinally or transversely along the line. The articulated arm is mounted on a trolley which is movable longitudinally of the working pit along tracks adjacent a side wall of the pit. The tool arm can pivot horizontally toward and away from the pit wall and can pivot vertically to enable a tool holder at the end of the arm to move from a position at or below floor level to a position in the path of an automobile body moving along the assembly line above the pit. The tool holder enables the tool to rotate through a path of 360.degree. and to tilt. The articulated arm is especially designed for use with a nut runner to tighten nuts and bolts underneath the automobile body, but can also be used with other tools.