Abstract: Roughness or jerkiness in a hydraulic swing circuit in an implement having a plurality of control circuits each having a work performing device (28), (30), (32) including a swing circuit having a hydraulic motor (32), which when under an aiding load may function as a pump, is avoided in a construction that includes a source (10) of hydraulic fluid under pressure and a plurality of control valves (22), (24), (26) for the circuits which are interconnected between the source (10) and the associated work performing device (28), (30), (32). The system includes a pair of hydraulic conduits (34), (36) extending from the control valve (26) for the swing circuit to the hydraulic motor (32). A pair of pilot operated, dual level pressure relief valves (56), (58) are connected oppositely across the conduits (34), (36) at a location between the control valve (26) for the swing circuit and the hydraulic motor (32).

Abstract: Roughness or jerkiness in a hydraulic swing circuit in an implement having a plurality of control circuits each having a work performing device (28), (30), (32) including a swing circuit having a hydraulic motor (32), which when under an aiding load may function as a pump, is avoided in a construction that includes a source (10) of hydraulic fluid under pressure and a plurality of control valves (22), (24), (26) for the circuits which are interconnected between the source (10) and the associated work performing device (28), (30), (32). The system includes a pair of hydraulic conduits (34), (36) extending from the control valve (26) for the swing circuit to the hydraulic motor (32). A pair of pilot operated, dual level pressure relief valves (56), (58) are connected oppositely across the conduits (34), (36) at a location between the control valve (26) for the swing circuit and the hydraulic motor (32).

Abstract: An anti two-blocking device for preventing a lower load block (46) on a crane (10) from coming in contact with an upper load block (44) affixed adjacent a boom point (40). The device comprises a cable follower (60) through which the crane's cable (26) is threaded, situated between the upper load block (44) and the lower load block (46). When the lower load block (46) is within a predetermined distance of the upper load block (44), the lower load block (46) reaches the cable follower (60) and exerts an upwards force which causes the cable follower (60) to activate an actuator (70) for a switch (72). The switch (72) deactivates all activity on the crane (10) which could cause the lower load block (46) to come in contact with upper load block (44). This activity includes lowering the boom (30), reeling in the cable (26) and extending the telescoping sections of the boom (32 and 33).

Abstract: The possibility of the end 26 of a boom 20 of a vehicle mounted crane being moved downwardly into engagement with part of the crane or the vehicle on which it is mounted and causing damage thereto during elevation of a mast 18 for the crane from a stowed position (FIG. 2) to an elevated position (FIG. 1) is avoided in a construction wherein the mast 18 is formed of a parallelogram linkage including rigid links 60 and cylinders 72 which assure that the attitude of the boom 20 relative to a base 10 for the crane will not change during elevation of the mast 18.

Abstract: A service vehicle includes a frame (10) on which a material dispensing system is mounted. The dispensing system includes reservoirs (30, 32) and (34) for various lubricants or the like and pumps (46) for pumping material out of the associated reservoirs (30, 32) and (34). The pumps (46) are driven by hydraulic motors (50) which may receive hydraulic fluid under pressure through electrically operated control valves (76) from a pressure compensated, variable displacement pump (60) driven by the engine (64) for the vehicle. The use of the pressure compensated variable displacement pump (60) achieves operating efficiencies.

Abstract: A service truck for servicing tires on off the road vehicles such as agricultural tractors includes an engine and an air compressor selectively operable by the engine. The vehicle includes a liquid tank for receiving and temporarily holding a liquid removed from such tires. A vacuum may be applied to the interior of the tires being serviced to withdraw the liquid for placement in the tanks by taking advantage of the vacuum present at the inlet of the compressor.

Abstract: A bead loosening tool for loosening the axially inner bead of a tire in a dual wheel set without disassembling the set and a method of bead loosening for loosening the axially inner bead of such tires. The apparatus includes a pair of elongated arms movable between open and closed positions. In the closed position, the arms are sufficiently close to each other as to be insertable in the space between the tires of a dual wheel set. A motor is provided for driving the arms apart to loosen the bead.According to the method, the tool is inserted between the tires of a dual wheel set and relatively movable surfaces of the tool positioned against the rim of the axially inner wheel of the set and the tire wall adjacent the bead of the axially outer tire in the set. The surfaces are then moved apart to achieve bead loosening.