Abstract: Apparatus and methods for metering fluid to a fluid actuator. An example apparatus may include a hydraulic actuator, a fluid chamber, and a hydraulic directional control valve. The fluid chamber may include a piston slidably movable between first and second ends of the fluid chamber and dividing the chamber into first and second chamber portions. The hydraulic directional control valve may direct a fluid from a fluid source into the first chamber portion to cause a volume of fluid to be discharged out of the second chamber portion into the hydraulic actuator to actuate the hydraulic actuator by a distance corresponding to the volume of fluid received by the hydraulic actuator.

Abstract: A water recirculation system for a steam power plant includes a tapoff line which receives water from a downcomer, and an economizer link which receives water from the tapoff line and transports the water to an economizer.

Abstract: A hydraulic system for use with a pressurized fluid includes a first cylinder and a second cylinder. A flow path links the first and second cylinders in fluid communication with each other. A first piston is disposed within the first cylinder and defines a first axis and a second piston disposed within the second cylinder. The first piston is movable along the first axis between a variety of operating positions and a rephasing position. The first piston has an exterior surface that defines a peripheral groove and several flutes. The flutes are oriented such that they are parallel to the first axis and intersect the peripheral groove, allowing the fluid to flow from the first cylinder across the flow path and into the second cylinder when the first piston is in the rephasing position thereby automatically rephasing the first and second pistons within the hydraulic system.

Abstract: A valve for balancing the braking system of a vehicle equipped with two separated master cylinders for the independent braking of the wheels situated at the two sides of the vehicle, includes two ring packings which cooperate with the intake of a transfer channel connecting both master cylinders, wherein at least one of the packings of the balancing valve is housed within a containment space suitable for allowing, in elastic conditions, a displacement of this packing that increases in noticeable manner the volume of the space which is located on the packing side communicating with the transfer channel. This packing may have a substantially usual shape, and the possibility of its displacement as a consequence of an elastic deformation of the packing may be entrusted entirely to the shape of the containment space, or a special shape of the packing itself. An elastic member brings the packing to its normal configuration when the cause of its displacement ceases.

Abstract: A synchronizing cylinder comprising a large diameter barrel and a small diameter barrel. The barrels are separated by a junction that is not fluidly sealed so that fluid can be communicated between them. The volume of the large diameter barrel is twice the volume of the small diameter barrel. The barrels comprise a first chamber adapted to communicate fluid to and from a hydraulic manifold, a second chamber adapted to communicate fluid to and from a first mechanism cylinder, and a third chamber adapted to communicate fluid to and from a second mechanism cylinder. The volumetric ratio of the barrels allows an equal volume of fluid to be communicated to and from the mechanism cylinders even though the volume of the barrels is not the same.

Abstract: A synchronizing cylinder that allows for the synchronized movement of multiple hydraulic mechanism cylinders having different sizes and volumes. In one embodiment, the synchronizing cylinder has a first chamber in fluid communication with a first mechanism cylinder and a second chamber in fluid communication with a second mechanism cylinder. The first mechanism cylinder has a first volume and the second mechanism cylinder has a second volume wherein the volume of the first mechanism cylinder is smaller than the volume of the second mechanism cylinder. The volume of the fluid being pushed from (or received by) the first chamber in the synchronizing cylinder is less than the volume of fluid being pushed from (or received by) the second chamber in the synchronizing cylinder so that the first and second mechanism cylinders extend and retract at the same speed and distance regardless of the smaller size and volume of the first mechanism cylinder.

Abstract: A selective position control system and method are disclosed. The system includes a processor, remote control and solenoid valve in conjunction with interacting valving, a potentiometer or ultra-sonic device and necessary wiring. The system interfaces wit the tractor's manual hydraulic lever operations which raise or lower equipment by effecting cylinder extensions or retractions. The system is separate from the tractor hydraulic system but interfaces by energizing a solenoid valve that stops oil flow and causes the manually detented tractor hydraulic valve to center from a working position. The system's processor establishes two programmed toggle switch settings; one typically slaved to the other. The system accommodates other manually activated positions, up or down, from the programmed positions, with return to set points of programmed positions. The remote control incorporates a toggle device with three positions, an up/down rocker switch, a set switch and an LED readout.

Abstract: A hydraulic system for synchronized movement of multiple cylinders in a horizontal plane includes a bidirectional pump, a shuttle valve cross-connected between pump outlets, flow-control check valves, and control valves which combine to reduce the number of valves in the hydraulic circuit and to reduce total cost of components for the system. The shuttle valve of the hydraulic system provides fluid for resynchronizing extension and retraction of multiple cylinder assemblies without disconnection of lines, provides air removal without disconnection of lines, allows easy addition/refill of hydraulic fluid, and allows excellent control of the extendable cylinder assemblies.

Abstract: A hydraulic system maintains squareness while extending an object via two lift cylinder assemblies. A hydraulic circuit is connected to the cylinder assemblies, and includes synchronizer with multiple isolated chambers corresponding to the cylinder assemblies, a rod extending axially through the chambers, and pistons mounted on the rod and associated with the isolated chambers. The hydraulic circuit operably connects a pump to the synchronizer and to the cylinder assemblies for controlling and providing synchronized movement of the cylinder assemblies. The hydraulic circuit includes valving for an automatic re-synchronization cycle, fill cycle, and air purge cycle. The system is effective for moving large objects in a non-binding manner, such as an extendable room on a recreational vehicle, while maintaining accurate squareness.

Abstract: A hydraulic platform lift, having hydraulic pump means and first and second hydraulic cylinders each having a piston member therein, each operatively coupled to a respective side edge of a platform to permit raising and lowering of the platform. A positive displacement valve is further provided, with the hydraulic platform lift and comprises a pair of juxtaposed cylinder members, each containing a longitudinally-movable piston, such pistons operatively coupled to each other so that movement of one piston causes an equal movement of the other. The positive displacement valve is adapted, when the pump means provides pressurized hydraulic fluid via a respective aperture to a first side of each of the pistons, to cause the pistons to be displaced an equal distance causing an equal egress of hydraulic fluid from the cylinder members via a respective aperture.

Abstract: Synchronizing hydraulic cylinders is provided by interconnected double-acting cylinders with dual pistons and central dividers which, with the pistons, divide the cylinders into four chambers. The outer chambers drive the pistons and the loads attached to the piston rods. The inversely interconnected intermediate inner chambers synchronize and balance piston and load movement. In double piston divided cylinders opposite outer chambers move a connected load and reversely connected inner chambers synchronize the load.

Abstract: A lift table maintains levelness while lifting a support surface via two or more lift cylinder assemblies. A hydraulic circuit is connected to the cylinder assemblies, and includes synchronizer with multiple isolated chambers corresponding to the lift cylinder assemblies, a rod extending axially through the chambers, and pistons mounted on the rod and associated with the isolated chambers. An axial passageway extends continuously through the rod and is connected to first passageways for communicating hydraulic fluid to one side of the chambers. The hydraulic circuit operably connects a pump to the axial passageway of the synchronizer and to second passageways connected to the chambers and to the cylinder assemblies for controlling and providing synchronized movement of the at least two lift cylinder assemblies. The hydraulic circuit includes valving for an automatic re-synchronization cycle, fill cycle, and air purge cycle.

Abstract: A lift table maintains levelness while lifting a support surface via two or more lift cylinder assemblies. A hydraulic circuit is connected to the cylinder assemblies, and includes synchronizer with multiple isolated chambers corresponding to the lift cylinder assemblies, a rod extending axially through the chambers, and pistons mounted on the rod and associated with the isolated chambers. An axial passageway extends continuously through the rod and is connected to first passageways for communicating hydraulic fluid to one side of the chambers. The hydraulic circuit operably connects a pump to the axial passageway of the synchronizer and to second passageways connected to the chambers and to the cylinder assemblies for controlling and providing synchronized movement of the at least two lift cylinder assemblies. The hydraulic circuit includes valving for an automatic re-synchronization cycle, fill cycle, and air purge cycle.

Abstract: The present invention includes a method for improving operating efficiency of a hydraulic actuator loop and an improved hydraulic actuator loop. The method includes transferring hydraulic fluid between a first and a second hydraulic actuator when the actuators are disengaged from a load and transferring hydraulic fluid from an energy source to each of the actuators separately when the actuators engage the load. The method also includes transferring fluid from the energy source to the first actuator when the actuators are approaching the load and transferring fluid from the first actuator to a drain when the actuators are retracting from the load.

Abstract: A cylinder apparatus capable of effectively restraining a loss of energy with a simple structure at a low cost. When a piston 16 of a main cylinder 11 cuts off a communication between a subchamber 20 and a supply/exhaust passage 32, a pressure of the subchamber 20 is pushed by the piston 16 and thereby increased. However, an exhaust fluid from the subchamber 20 having the increased pressure is fed to a subcylinder 62. A piston 48 is moved while controlling a velocity by a flow rate control valve 70 in synchronization with the piston 16. This arrangement eliminates a necessity for a special position detector, etc.. The structure is therefore simplified, and the cost decreases. Simultaneously, the energy can be effectively utilized because of employing the exhaust fluid.

Abstract: An hydraulic piston and cylinder unit with a piston rod and first and second cylinders. The piston rod extends into the first cylinder, and the first cylinder extends into the second cylinder. The piston rod is connected to a first piston which divides the first cylinder into first and second chambers. A second piston, connected to the first cylinder, divides the second cylinder into first and second chambers. The second chambers of the first cylinder, and the first chamber of the second cylinder are in fluid communication such that an extension of the first cylinder causes a proportional extension of the second cylinder. A similar effect occurs during retraction of the cylinders.

Abstract: A fluid circuit assembly for maintaining substantially constant pressure between two abutting solid objects, the circuit assembly comprising a master cylinder assembly, a plurality of working cylinder assemblies, piston rods extending from the working cylinder assemblies, a spool on distal ends of the piston rods adapted to engage a surface against which it is desired to maintain constant pressure, the master cylinder and the working cylinders having first chambers in communication with a first fluid circuit, the master cylinder having a second chamber in communication with a source of gas under a selected substantially constant pressure, said gas being in communication with a gas reservoir portion of a liquid/gas tank, a liquid reservoir portion of said tank being in communication with second chambers of said working cylinder assemblies, such that upon change of pressure on the spool by the surface, a reaction is generated in the circuit assembly, such as to move the spool to restore a selected pressure betw

Abstract: Hydraulic fluid under pressure is selectively supplied to multiple drive cylinders that are interconnected to one another and which have bypass lines allowing excess fluid to return to the source of hydraulic fluid as needed. Each drive cylinder receives a double acting piston and each piston is carried by and axially displaces a component pump shaft as it reciprocates within the drive cylinder under the influence of hydraulic pressure. A free end of each pump shaft carries a trip member that trips upper and lower limit switches when the piston reaches its top dead center and bottom dead center positions, respectively.

Abstract: A master/slave hydraulic system (10) comprises a master cylinder (12), slave cylinders (14-22), and a rebound compensator (72) for eliminating the effects of expansibility in the system on the lower stroke of the cylinders so that accurate depth control across an agricultural implement can be achieved and maintained. The rebound compensator (72) includes a direct pressure reducing and relieving valve (74) and a check valve (86). A flow restrictor (90) is preferably provided on the high-pressure supply port of the pressure reducing and relieving valve (74).

Abstract: A master-slave hydraulic control system preferably for actuating a vehicle clutch utilizes single-acting hydraulic cylinders which are both connected to a fluid reservoir. The higher mounted cylinder has a bleed valve in the line connecting that cylinder with the fluid reservoir. The lower mounted cylinder is connected to the fluid reservoir via a check valve. The check valve allows fluid communication between the reservoir and the lower cylinder when the pressure within that cylinder is below a predetermined value. The hydraulic system may be bled regardless of the position of extension of either cylinder.

Abstract: A hydraulic system for lifts provided with two independently supported parallel platforms comprises at least two cylinder-piston units (80, 81) for raising the platforms, a metering device (7) for feeding identical quantities of fluid to said two units, and a balancing device (74, 75) operated by means (31, 32) for measuring the height difference between the platforms and arranged to feed a quantity of supplementary fluid to that cylinder-piston unit (80) or (81) operating the lower platform by withdrawing it from that cylinder-piston unit (81) or (80) operating the higher platform.

Abstract: A hydraulic system is disclosed which provides automatic proportional actuation of pairs of hydraulic cylinders. The proportioning mechanism comprises one or more standard hydraulic cylinders.

Abstract: An improved rephasing master cylinder in which the cylinder wall approximate the end of the cylinder has a longitudinal bleed passage in the cylinder wall at one end connected to a lateral passage opening into the forward cylinder chamber while the opposite end of the longitudinal passage connects with the rearward chamber of the cylinder when the cylinder piston is located therebetween. This longitudinal bleed passage permits the restricted flow past the master cylinder piston when the piston is nearing and at the end of its stroke, thereby causing both master and slave pistons to complete their respective strokes.

Abstract: A remotely controllable adjustable-stroke fluid cylinder system is described in various embodiments. The system includes a floating stop piston (48) and a main piston (24,224) which is controlled by a valving system (70) and which has visual indicator means having a graduated scale (69,169).

Abstract: A closed circuit power system is disclosed herein having a hydraulic power device incorporated therein which includes an input piston and cylinder assemblage and an output piston and cylinder assemblage connected together by a fluid conduit so as to operate in unison. The input assemblage includes a piston moved by an input ram so as to apply a fluid pressure via the conduit to the output assemblage. The output assemblage includes a pair of pistons operating in unison in separate chambers in response to the applied fluid pressure for moving an output shaft. The pair of pistons include pressure faces against which the fluid pressure is applied which are of equal area but different shape. A selected piston of the output assemblage includes conical forward and rearward faces with a corresponding or matching concave recess in the rear cylinder wall.

Abstract: An hydraulic boat lift utilizing readily available city water as the pressure fluid comprises one or more lift cylinders buried vertically under a body of water with the upper ends of the cylinders protruding into the water. To increase the pressure of the water and the resultant lift of the hydraulic cylinder, a single booster cylinder and a transfer cylinder for each of the lift cylinders are provided with the piston in the booster cylinder having a larger area than any of said transfer pistons and being rigidly connected to one another so as to provide equal displacements of the booster and transfer pistons and to simultaneously operate all of the lift cylinders at equal rate of displacement. Means are provided for automatically operating the booster cylinder through a number of charge and discharge cycles to accomplish complete elevation of a cradle.

Abstract: A synchronizer is provided for synchronizing the movements of two hydraulic actuators. The synchronizer consists of a two-piston pump which supplies hydraulic fluid to both actuators. The two pistons are mechanically connected so as to move simultaneously through equal distances, and on each complete stroke of the pump, each actuator receives fluid from both cylinders of the pump, so that both actuators receive precisely equal amounts of fluid.

Abstract: A power piston apparatus, comprising two or more double acting hydraulic piston drive means in which the cross-sectional areas of the pistons are identical and the cylinder spaces or chambers of which are hydraulically interconnected in crossed fashion above and below the pistons in the case of two cylinders, while being connected in series in the case of more than two cylinders having separately closed oil spaces of identical volumes, with each such oil space being connected to a positive-pressure oil supply through check valves for replenishing the leakage oil, and wherein said piston drive means have associated therewith metering cylinders with a coaxial and/or parallel direction of stroke, i.e. with mechanical connections between the ends of the piston rods.

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: A machine for washing and/or filling containers such as beer kegs has a walking beam conveyor for moving the containers through the machine from one station to another. The walking beam is raised and lowered by two spaced-apart upright pneumatic rams and to maintain the walking beam in its correct attitude regardless of variations with loads upon it, a spaced-apart pair of double-acting hydraulic pistons and cylinders are arranged to act between the walking beam and a base frame of the machine, the cylinders being cross-connected so that the pistons are constrained to move in unison by the movement of hydraulic liquid between the cylinders. Preferably, each of the hydraulic pistons and cylinders is incorporated co-axially as a unit with one of the pneumatic rams.

Abstract: A tractor-trailed plow having a steerable rear wheel is provided with a hydraulically powered steering system including master and slave cylinders arranged to steer the rear wheel in response to changes in the angular position of the plow with respect to the tractor. A rephasing valve system is provided that is responsive to turning of the tractor for proper phasing of the master and slave cylinders.

Abstract: The invention is especially suitable when front and rear wheels are hydraulically steered, each set by its own hydraulic cylinder, the two cylinders being connected in hydraulic tandem so that the same angularity of steering will be imparted to both sets of wheels. The self-synchronizing of the present invention overcomes a serious prior fault that occasionally a nonsynchronous relationship would develop. The present invention opens a synchronizing valve on the occasion of each extreme swing of the wheels. A check valve then ensures a synchronized return swing.

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: Hydraulic control apparatus for automatic remote control of a hydraulic actuating ram. The apparatus has a double-acting slave cylinder connectable hydraulically to an actuating ram, and a double-acting master cylinder the piston of which is mechanically connected to the piston of the slave cylinder, the master cylinder being operable by hydraulic pressure supplied via a pilot-operated valve arranged automatically to reverse the stroke of the master ram at limits set according to the desired stroke of the actuating ram. The control apparatus may be used for controlling actuating rams which effect reciprocating pivotal movement about one or more axes of a water jet monitor.

Abstract: A hydraulic linkagae for transmitting reciprocating motion comprising a master unit, a slave unit, the master and slave units each comprising a pair of interconnected rod pistons reciprocally moveable within the cylinders in opposite directions by a force applied to the pistons, hydraulic lines connecting one master cylinder to one slave cylinder for transmitting motion from master to slave, a reservoir, a pair of one-way pressure valves mounted in opposite directions and in parallel between the reservoir and each master-slave connection so that volumetric increases in the fluid in the system will be forced out through a first valve of each valve pair and to the reservoir, and volumetric decreases in the fluid in the system will draw fluid from the reservoir through a second valve of each valve pair, thereby providing volume change compensation.

Abstract: 6.