Abstract: A fluid control system (10) has a first fluid pump (12) for supplying pressurized fluid in interrupted series to first and second work elements (14,16). The first work element (14) in the series has priority which prevents simultaneous full power operation of the first and second work elements (14,16). A second fluid pump (24) is capable of supplying pressurized fluid to the second work element (16) only upon receiving a signal indicating that pressurized fluid from the first pump (12) is being directed to the first work element (14). The subject fluid control system (10) is especially useful with a tree harvesting machine where it is beneficial to propel the machine and at the same time rotate the upper structure.

Abstract: A multiple flow and direction control valve connectable to a plurality of separate fluid sources, the valve having a fluid power port and a fluid exhaust port and a first movable valve body being operable to add or subtract the flow rates of a plurality of fluid sources to either the power port or the exhaust port. The valve has a directional control member having two power ports and one exhaust port and being operable in a first position to apply power fluid to one of the power ports, exhaust fluid being returned through the second power port and routed out of the exhaust port and in a second position said power fluid being routed to the other power port and returned through the first power port to the exhaust port. The valve includes modified directional control members which may be stacked to sequentially provide directional control for a plurality of outputs.

Abstract: A bidirectional, multiple speed hydraulic actuator, including a differential piston (10, 24, 26). First and second ports (28, 30) are respectively in fluid communication with opposite sides of the piston and there is provided a pressure fluid supply line (40) along with a pressure fluid drain line (44). A control valve (14) is disposed between the ports and the lines and is movable step-wise through five positions providing for nulling of piston movement, and slow and rapid piston movement in either of two directions. A shifting device (60) is provided for the valve.

Abstract: A pneumatic actuating arrangement for to and fro movements, especially of a central locking system for motor vehicles, with an excess pressure source and with a vacuum source and with at least one pneumatic working device whose working chamber is adapted to be selectively connected to the excess pressure source or to the vacuum source by way of a shifting valve shiftable between two end positions. An intermediate for the shifting valve is provided in which position the shifting valve becomes temporarily effective during the transition from the one end position into the other end position so that the working chamber is conected to the atmosphere.

Abstract: A vacuum type brake booster device including an input rod with an adjustable stop mechanism for enabling the input rod to have such a normal, full-retracted position as to hold the booster control valve in a neutral position to keep the second working chamber of the booster out of communication with the first working chamber thereof as well as with the atmosphere while holding the booster output rod in direct abutting engagement with the brake master cylinder piston. There is no delay in operation of the brake master cylinder when the brake pedal is depressed.

Abstract: Fluid operating mechanism providing stationary and rotary companion parts of a fluid coupling having in the rotary part a cylinder with a piston defining therein opposite chuck closing and opening cylinder ends, and ports in both coupling parts which, together with two fixed conduits, form fluid passages to the opposite cylinder ends, with each passage having an interposed check valve and an associated plunger, of which the check valve in either passage will open to admit fluid into, but will normally close to block fluid flow from, the associated cylinder end, and the plunger associated with the check valve in either passage will open this valve on being subjected to the pressure of fluid in the other passage.

Abstract: A pneumatically operated brake booster comprises a hydraulic cylinder disposed within a hydraulic braking circuit connecting a master cylinder to wheel brake cylinders to increase the braking pressure trapped within the wheel brake cylinders and a servomotor for pneumatically activating the hydraulic cylinder in response to hydraulic pressure from the master cylinder. The servomotor has a spring loaded diaphgragm piston forming a negative pressure chamber and a variable pressure chamber, the former being in connection to a source of negative pressure and the latter being connected to the atmospheric pressure in response to master cylinder pressure applied to the hydraulic cylinder. The brake booster includes a control valve which is provided to selectively connect the variable pressure chamber of the servomotor to such a positive pressure source as exhaust pressure to obtain additional pressure in an emergent braking operation of the vehicle.

Abstract: A device for controlling hydraulic motors as in an aircraft "fly-by-wire" system wherein redundant hydraulic motors and controls are required to protect against failure of portions of the system or device. The device includes two master valves for controlling flow of fluid to and from the motors, one controlled by electrical signals from a command station and the other controlled mechanically through manual or automatic operation. There is a transfer valve for selecting which of the master valves is to be operable and to provide for smooth transition of control from the electrically controlled valve to the mechanically controlled valve.

Abstract: In a pneumatic brake booster, positive and variable pressure chambers on opposite sides of a spring loaded diaphragm piston both communicate with an air pressure source under inoperative condition of the booster; only the positive pressure chamber communicates with the air pressure source while the variable pressure chamber communicates with atmospheric pressure in response to activation of the booster to operate the piston.

Abstract: A power brake control device for vehicles disposed between a manual brake operating member and wheel brake members which includes an accumulator, a housing including a first inlet port connected to a hydraulic pressure source, a second inlet port connected to the accumulator hydraulically disposed and interconnected between the pressure source and the first inlet port, a first outlet port hydraulically connected to the wheel brake members and a second outlet port connected to the reservoir. A spool valve is also slidably disposed within the housing and is movable by operation of the manual brake operating member for controlling hydraulic communication between the first inlet and the second outlet port with a piston being slidably disposed within the housing for connecting the first outlet port with the first inlet port, one end of the piston being secured to the spool valve for unitary movement therewith.

Abstract: A manually operable valve in a power tongs assembly has, in combination therewith, an electro-hydraulic interface module. The interface module comprises an electrically responsive solenoid valve connected in hydraulically parallel path to the manually operated valve. The manually operated valve may be selectively disenabled and the electrically responsive valve simultaneously enabled to permit electrical control of the power tongs assembly.

Abstract: A self-advancing mine roof support is provided, in addition to the normal manually operable control valve means for controlling raising and lowering of the roof-engaging structure of the support and operation of the advancing means, with an automatic sequence control valve means operable in response to a control signal from a position removed from the support, for example from an adjacent support, and an isolating valve means arranged so that control of the various operations can be effected either by means of the manually operable means or from the safety of a location spaced away from the support being controlled by means of the automatic valve means each independently of the other.

Abstract: A hydraulic positioning drive with a physically separated work cylinder which is connected via pressure oil lines, comprises a follow-up cylinder mounted at the positioning drive or in the immediate vicinity thereof, of the same type and the same volume as the work cylinder, which is hydraulically connected in series with the latter, so that its piston moves synchronously with that of the work cylinder. The piston position of the follow-up cylinder is sensed electrically and used as the positioner position. For synchronizing, both cylinders are connected in parallel from time to time and their pistons are run into the end positions.

Abstract: Apparatus and controls are provided for resistance welding one workpiece or body to another. A movable electrode is driven by a cylinder and a piston which are positioned in tandem with a second cylinder and a second piston. The design enables a small pressure applied to the second piston to result in a large force applied by the electrode to the bodies to be welded, with a back-up electrode located on the opposite side of the bodies. Controls for the apparatus enable the force applied by the movable electrode to the bodies to be changed almost instantaneously so that the force applied can be raised and lowered during the actual resistance welding cycle. In some intances, by way of illustration, the pressure is raised while the welding current is on, and, in other instances, the force is decreased and then increased again during the welding cycle.

Abstract: A sequential valve mechanism for power brake units moves in one direction for sequentially connecting a chamber to three different pressure sources, and moves in an opposite direction for sequentially connecting the chamber to the different pressure sources in reverse order.

Abstract: The apparatus has a pointed-nose hollow cylindrical body with a closed rear portion. Disposed inside the body, so as to enable reciprocation and rotation about the axis of the body, is a stepped striker which can be locked against rotation about the axis of the body in two positions, the positions corresponding to forward and reverse movement of the apparatus.For the purpose of admitting compressed air into a forward working chamber, the striker is provided with a central passage permanently connected to a rear working chamber and at least two radial passages which provide communication between the central passage and an outer cylindrical surface of a large step of the striker. The radial passages are displaced relative to each other both circumferentially and longitudinally along the axis of the body.

Abstract: A hydraulic power circuit for operating hydraulic motors at several speeds includes first and second fluid sources and a valve assembly for combining flow from the second source with flow from the first source as a faster motor speed is required. The valve assembly includes a first valve controlling the flow of fluid from the first source to the motors while a slow motor speed is required. The valve assembly also includes a fluid actuated valve controlling the flow of fluid from the second source to the motors as a faster motor speed is required. The fluid actuated valve is actuated by flow from the first source through metering ducts. Once the fluid actuated valve is actuated, fluid from the second source is mixed with fluid from the first source and the valve assembly communicates the increased flow to the motors thus obtaining a faster motor speed.

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: In a mineral mining installation employing a series of shifting rams for advancing a scraper-chain conveyor provided with a guide for a mining machine a control system with a central control station for transmitting control signals. The control signals serve to actuate local control valves, possibly in time dependence, to cause a selected one or group of metering devices to transfer a pre-determined volume of pressure fluid to one or more of the rams to effect said advancement. This volume of pressure fluid is some fraction of the total capacity of the ram or rams in question so that by repeatedly transmitting control signals the device or devices can perform successive cycles of operation to thereby cause the ram or rams associated therewith to extend in defined increments.

Abstract: A fluid actuated, valveless sanding tool is disclosed which comprises a housing containing a cylinder, a double-ended piston mounted for reciprocal movement within the cylinder, a mounting plate to which an abrasive tool can be attached, and a double rack and pinion connecting means reciprocally driving the mounting plate. A fluid supply system delivers pressurized fluid to a central portion of the bore and a vent system permits venting of the ends of the cylinder. The piston has two end seals and three internal, main seals which maintain a fluid tight relationship with the inner cylinder wall. Two internal passages in the piston are in communication with the annular areas between the three main seals and the respective ends of the piston.

Abstract: A conveyor apparatus for elevating loose bulk material from one level to another, as in self-unloading ships, and more particularly a dual belt conveyor-elevator having a relatively long horizontal feed section, and further including a belt take-up apparatus and system including a normal pressure mode for tensioning the outer belt of the dual belt conveyor-elevator under normal operating conditions, the belt take-up apparatus and system also including a high pressure mode which is connected in tensioning relation to the outer belt of the dual belt conveyor-elevator upon loss of motive driving power to the dual belt conveyor-elevator. The high pressure mode is capable of substantially immediately taking up slack which develops in the outer belt, particularly in the horizontal feed portion thereof, with consequent prevention of spillage of load material, when the driving power for the dual belt conveyor-elevator is interrupted.

Abstract: Apparatus for use in a vehicle having a hydraulically actuated steering mechanism and a hydraulically actuated implement. The apparatus comprises a housing, which includes a fluid inlet port, first and second working ports, for connection with the steering mechanism, a fluid return port and an auxiliary port for connection with the implement. A metering mechanism is located in the housing, and a first valve is movably located within said housing. The first valve has a neutral position communicating the inlet with said auxiliary port and blocking the inlet from said first and second working ports. The valve also has first and second actuated positions communicating said inlet port with said metering unit and communicating flow from the metering unit to said first or second working ports respectively.

Abstract: A hydraulic brake booster is disclosed which is normally actuated by a primary pressure source, but which may be actuated by a secondary pressure source during failure of the primary pressure source. The booster includes a spool valve which controls communication between the primary pressure source and the booster pressure chamber. The spool valve is actuated by a control pressure which is generated by the vehicle operator when a brake application is effected. The control pressure shifts the spool valve to cause the latter to communicate fluid pressure from the primary pressure source into the pressure chamber. A pressure differential responsive piston is responsive to a pressure differential between the control pressure and the pressure communicated into the booster pressure chamber.

Abstract: In an improved method and apparatus for harvesting a tree, the pressure exerted on the tree by a grapple assembly is at a first preselected value during shearing of the tree trunk and positioning the severed tree for further processing. The pressure exerted on the tree by the grapple assembly is thereafter reduced to a second preselected value and the tree is further processed.

Abstract: A relay valve for transmitting an operational signal to a first brake applying servomotor in a trailer upon actuation of a second brake applying servomotor in a tow vehicle. The relay valve has a housing with a movable wall which sequentially interrupts the communication of vacuum to a power chamber in the first brake applying servomotor and thereafter allows air to be communicated to the power chamber. With air in the power chamber, an operational pressure differential will be developed which will operate the first brake applying servomotor.

Abstract: A fluid-operated apparatus receiving an input pressure signal exhibits a hysteresis or deadband effect by responding to an increasing pressure signal at a first level and a decreasing signal at a second and lower level. The apparatus includes a spool valve to which the input pressure signal is applied at one end of the spool. The opposite end of the spool having a given cross sectional area projects into a pressure chamber and contacts the poppet of a poppet valve held closed by a regulated pressure in opposition to forces produced by the spool. The seat of the poppet valve surrounds an opening into the pressure chamber so that the regulated pressure is admitted into the pressure chamber when the spool pushes the poppet open.

Abstract: In a mineral mining installation employing a series of shifting rams for advancing a scraper-chain conveyor provided with a guide for a mining machine a control system with a central control station for transmitting control signals. The control signals serve to actuate local control valves, possibly in time dependence, to cause a selected one or group of metering devices to transfer a pre-determined volume of pressure fluid to one or more of the rams to effect said advancement. This volume of pressure fluid is some fraction of the total capacity of the ram or rams in question so that by repeatedly transmitting control signals the device or devices can perform successive cycles of operation to thereby cause the ram or rams associated therewith to extend in defined increments.

Abstract: Apparatus for harvesting, delimbing and cutting trees into sections is disclosed herein. The harvesting apparatus includes grapple means and cutter means on a mast which is supported on a boom of a vehicle. The delimbing and cutting into sections is accomplished with a separate frame that may be in the form of a trailer processor attached to the vehicle and positioned so that the mast and boom may be utilized for forcing the tree into engagement with a tree advancing mechanism on the trailer and the cutter means on the mast may be utilized to cut the delimbed tree into sections. The system is also designed so that the hydraulic circuitry for driving the vehicle may be used as the power source for the processor.