Abstract: A rotary actuator (11) having a vane (24) which is pivoted in a chamber (13) by fluid pressure to turn an actuator shaft (18) includes internal sump cavities (41A, 41B) that collect abrasive particles from the fluid and which hold such contaminants away from the path of movement of the vane (24). Shields (49A, 49B) protect the sumps (41A, 41B) from fluid turbulence. A magnetic element (47A, 47B) at each sump (41A, 41B) attracts and holds ferromagnetic particles and may be removed for cleaning without a general disassembly of the actuator (11) and with only a minimal draining of fluid. Actuator (11) durability is increased by reducing wear of moving components and maintenance is facilitated by simplifying cleaning. Among other uses, the invention may be employed in actuators (11) which swing a backhoe (34) relative to a supporting vehicle (32).

Abstract: Swing motors employed on backhoes and like constructions vehicles are interconnected between a tractor frame and a mast frame to selectively rotate the mast frame relative to the tractor frame. In addition to posing assembly and disassembly problems, conventional mounting arrangements for swing motors of this type oftentimes subject various spline connections, pins, and bearings to undue wear. The swing motor mounting arrangement (10) of this invention overcomes the above problems by providing a pair of first brackets (20) fro pivotally mounting a mast frame (15) on a tractor frame (16) and a pair of second brackets (26) for securing opposite ends (14) of a shaft (13) of a swing motor (11) to the mast frame (15). A housing of the swing motor (11) is connected to the tractor frame (16) whereby pressurization of the motor will rotate the shaft (13) relative to the housing (12) to selectively swing the mast frame (15) relative to the tractor frame (16).

Abstract: Locking apparatus encloses and frees an end portion of a shaft for rotation at a first position of the apparatus relative to the shaft. The locking apparatus further encloses, engages, and prevents rotation of the shaft end portion at a second position of the apparatus relative to the shaft. Respective ends of the apparatus are oriented toward the shaft at the first and second positions. The first position of the locking apparatus permits rotation of the shaft and the second position prevents shaft rotation and related movement of associated implements.

Abstract: A hydraulic system for use in extremely cold environments has a pump for passing hydraulic fluid from a reservoir to a hydraulic cylinder of a work element via a control valve that is positioned a relatively great distance from the hydraulic cylinder. Fluid pathways are provided for substantially continuously moving hydraulic fluid between the control valve and hydraulic cylinder during operation of the pump.

Abstract: A hydraulic circuit is provided for powering and controlling an excavator or the like, with a plurality of pumps supplying pressurized fluid for the circuit. The circuit is arranged so that fluid is provided in a manner to permit positive independent control of the various implement motors of the machine, with means provided so that fluid may also be combined to operate selected implement motors for faster operation and maximum efficiency of the machine.

Abstract: A control system for a vehicle parking brake-actuator which releases the brake when subjected to fluid under pressure and which automatically sets the brake by spring force when the fluid pressure is relieved therefrom, the actuator being controlled by a valve which blocks or allows the relief of fluid pressure from the brake-actuator. The control system includes a solenoid for moving the valve to pressure-blocking position, a spring for moving the valve to pressure-relieving position when the solenoid is de-energized, and includes an electrical circuit for de-energizing the solenoid and causing an automatic setting of the brake if the vehicle engine is stopped or if there is a loss of oil pressure or electrical power. The brake can also be set by the operator when the engine is running.