Abstract: A pneumatically actuatable linear drive for automatic spot welding machines includes a cylinder, a piston rod with segments and pistons and an intermediate bottom between the pistons for dividing the cylinder into pressure chambers. An axial conduit in the segments has a check valve. Radial conduits communicate between the axial conduit and the pressure chambers. Air line connections and a throttle valve lead into the pressure chambers. One piston on one segment moves toward and away from the closed end into end and terminal positions for closing and opening the radial conduits. The end and terminal positions of the one piston are determined by a cap screw of the check valve having an axially parallel conduit and by a spring on one of the segments. A connecting conduit contains the throttle valve. The intermediate bottom has a peripheral annular conduit communicating with one of the air line connections and through the connecting conduit with one of the pressure chambers.

Abstract: The invention concerns a tilt correction system with at least one pair of cylinder and piston assemblies which are hydraulically operated. The extent of tilt correction is limited by grooves internal to the cylinders of the assemblies which short hydraulic potentials once the pistons of the assemblies have moved from a rest position to a position adjacent the grooves. A preferable arrangement includes connecting each assembly between an anti-roll bar and an axle.

Abstract: A hydraulic platform lift for use on trucks and truck trailers has two hydraulic cylinders, one on each side of a door. The cylinders are phasing cylinders in that one cylinder is larger than the other cylinder by a specific ratio. The cross-sectional area of the fluid in the rod end of the larger cylinder minus the area of the rod is equal to the cross-sectional area of the smaller cylinder. A connecting line interconnects the rod end of the large cylinder with the cap end of the small cylinder. Hydraulic fluid can be directed by a controller into the cap end of the large cylinder or the rod end of the small cylinder. For upward movement, hydraulic fluid is forced into the rod end of the small cylinder. This in turn forces hydraulic fluid through the connecting line into the rod end of the large cylinder, thereby raising both pistons.

Abstract: An article handling apparatus is disclosed which comprises two independently controllable fluid actuated drives. The first fluid actuated drive comprises a cylinder and a differential piston which defines a large chamber and a smaller chamber. Also, a control system is provided which maintains a differential pressure between the large and small chambers in each of several operating positions. The second fluid actuated drive is mounted to the movable member of the first drive, and the second drive is controlled by fluid lines leading respectively to the large and small chambers of the first drive.

Abstract: Load sensing hydraulic systems conserve energy by generating only the fluid flow demanded by the system and at a pressure only slightly greater than the highest load pressure of the system. Optimizing the operating characteristics of the system for certain applications also caused the variable displacement pump to go to its maximum displacement setting with the excess fluid generated thereby not doing any useful work. The load sensing hydraulic system includes a flow control valve connected to a directional control valve and has an operating position in which fluid exhausted from a hydraulic jack is transmitted therethrough to a tank. A signal valve is disposed in a control pressure signal line for controlling fluid flow therethrough from a supply conduit to one end of the flow control valve. When the signal valve is blocking fluid flow through the signal line, the flow control valve is in the above-noted operating position.

Abstract: A lifting apparatus has two posts on either side. A lifting or cross member extends between them and is supported on carriages slidably mounted on the posts. Support arms or the like extend out from the support carriages for supporting a vehicle or other load. Actuators are provided for driving the carriages up and down. The actuators can be hydraulic cylinders connected in a master and slave relationship with a hydraulic connection between them through the cross member. Additionally, mechanical safety catches can be provided which are connected by a cable or the like through the cross member, to permit a single handed operation of them. In the further aspect of the invention, a mechanism is provided for locking the support arms angularly, which mechanism includes plungers that contact the ground and automatically free the support arms when the apparatus is lowered.

Abstract: A boom and bucket system for a loader includes a bucket leveling valve which maintains a desired orientation of the bucket as the boom is raised or lowered. A hydraulic circuit automatically and selectively supplies fluid for bucket leveling from boom cylinder return flow, from a pump, or from both in varying proportions.

Abstract: A three point implement hitch arrangement for a tractor including a frame assembly, a pair of draft arms pivotally supported on the frame assembly intermediate their ends and lift cylinders having a cylinder portion pivotally supported on the frame assembly above the draft arms and having a rod portion pivotally connected to the draft arms, forwardly of the draft arm pivotal connections. The lift cylinders are connected in series, wherein the area of the rod end of one cylinder is equal to the area of the head end of the second cylinder, whereby the cylinders may be operated independently to tilt the implement or operated in unison to lift the implement, eliminating the requirement for a complex structural support and control.

Abstract: A fluid operated circuit for controlling the movement of pistons contained in the drive and idler cylinders of a conventional dual post vehicle lift assembly of the type wherein the cylinders are hydraulically connected in tandem so that movement of the idler cylinder piston is dependent upon movement of the drive cylinder piston and wherein the pistons, while operative to lift and lower movable article supporting structures, are not fixedly connected thereto.

Abstract: A combined pneumatic and hydraulic pressure transducer is comprised of a pressure capsule with an open interior divided into first and second sections by a partition wall, and a respective axially displaceable diaphragm extends across each of the sections defining third and fourth pressure chambers which change in volume due to axial displacement of the respective diaphragms. A rigid piston intermediate member extends through the partition wall and joins the diaphragms to move together. Connections communicating between the third pressure chambers and between the fourth pressure chambers pass through the intermediate member. A respective hydraulic cylinder at each end of the pressure capsule receives and operates upon a respective end of the intermediate member.

Abstract: A fluid actuator including at least two cylinders connected to a common pressurized-fluid supply mechanism. Actuation units are connected to piston rods of the cylinders, respectively. The piston of one of the cylinders is operated by pressurized fluid, and when the piston is moved back, the pressure in the cylinder is increased to operate the piston of the other cylinder. The actuation units are thus operated with a certain amount of interval of time or in a synchronous mode.

Abstract: Hydraulic lift cylinders on a transversely extending implement frame, such as a multi-section hinged implement, are connected by valve and conduit structure to operate as single acting cylinders in parallel during an automatic depth control mode for individual cylinder control. An operator control valve and depth sensing valve permit the operator to change to a fast raise/fast lower mode wherein flow control structure causes the lift cylinders to operate substantially in series for raising and lowering the implement in level fashion across its width to and from a transport position.

Abstract: A pneumatic cylinder having an elongatged cylinder member, a reciprocally movable piston, an elongated slot formed in the cylinder member, a seal for sealing the slot during reciprocal movement of the piston and a transfer means for transferring reciprocal movement of the piston to a workpiece. The above pneumatic cylinder includes a mechanisn for providing pneumatic fluid pressure to a secondary pneumatic unit connected to, and movable with, the piston including a manifold connected with the transfer means and conduit members extending from the pneumatic chambers in the cylinder member for directing pneumatic pressure from such chambers to the transfer means.

Abstract: Level lifting and lowering of a working implement in combination with a hydraulic boom is provided through a hydraulic circuit and valve including a shuttle check valve, a rotary flow divider and a counterbalance valve. Selective operation results in the working implement being raised or lowered in a level displacement relative to the ground.

Abstract: A hydraulic operated control system for remotely operating a walk-behind soil compactor. A remotely operated three-position valve is connected to the pressure line of the hydraulic system of the soil compactor and serves to control the flow of hydraulic fluid to opposite ends of a hydraulic cylinder unit that is operably connected to a hydraulic pump which operates the speed and direction control for the compactor. The cylinder unit includes a piston that is slidable within the cylinder and the piston is biased to a neutral position by springs. Through remote operation of the valve, hydraulic fluid will be directed to either end of the cylinder to provide direction and speed control for the compactor. A deadman switch is located on the remote control panel and manual release of the deadman switch will open the hydraulic circuit between the opposite ends of the cylinder to prevent fluid from being directed to the cylinder and will enable the springs to return the cylinder to a neutral no speed position.

Abstract: The method and system employing double-acting, fluid-driven, twistor-pairs as combined flexural supports, joints, torque motors and linear-response angular deflectors in arms and legs of robots. Thus, the twistor-pairs at each joint advantageously serves as hinge or flexural support for the limb supported by the joint and simultaneously serves as double-acting turning motor for moving the portions of the arm or leg supported by the twistor pair. Various jointed-arm or jointed-leg robots, called "arthrobots" are shown embodying the invention. Controllably varying fluid pressure P.sub.1 and R.sub.2 (usually pressurized air) fed into elastic shells forming respective fluid chambers of a double-acting, twistor-pair at each joint, deflects a limb into predetermined predictable angular positions, depending upon these pressures.

Abstract: Piston rods (60, 62) of three linear hydraulic motors (36, 38, 40) are connected at their outer ends (64, 68) to two spaced apart transverse frame members (10, 12). A cylinder housing (72) is driven back and forth along each pair of piston rods (60, 62). Three transverse drive beams (48, 50, 52) are provided. Each drive beam (48, 50, 52) is directly connected to an associated one of the cylinder housings (72). Three sets of floor slat members (1, 2, 3) are provided. Each set (1, 2, 3) is connected to an associated one of the transverse drive beams (48, 50, 52). The linear hydraulic motors (36, 38, 40) are operated for moving the floor slat members (1, 2, 3) in one direction, for advancing a load, and for retracting them in the opposite direction. Each cylinder housing (72) has four fluid chambers (82, 84, 86, 88). The first and third chambers (82, 86) are interconnected and the second and fourth chambers (84, 88) are interconnected.

Abstract: An elevating apparatus including a base, a platform, at least a pair of pivotally interconnected boom assemblies connecting the base and the platform together, the pair of boom assemblies including a pair of hollow middle booms pivotally interconnected substantially centrally thereof by a shaft, and upper and lower booms telescopically disposed in each of the middle booms and movable out of upper and lower ends of the middle booms, the lower booms having ends pivotally mounted on the base in spaced relation and the upper booms having ends pivotally mounted on the platform in spaced relation, each of the boom assemblies including a synchronizer for synchronizing intervals of extension of the upper and lower booms from the middle boom, a pair of hydraulic mechanisms operatively coupled between the shaft and the base at spaced locations thereon for moving the middle booms to displace the upper and lower booms into and out of the middle booms to lift and lower the platform, and a controller for selectively contro

Abstract: An hydraulic circuit includes a master cylinder and at least one slave cylinder connected in series circuit. An auxiliary discharge conduit with a solenoid-actuated valve is provided to selectively permit the master cylinder to extend its full useful range after the slave cylinders are fully extended. Under normal operation the valve is closed so that the cylinders may extend together. When the slave cylinders reach full extension, the main control valve is kicked out of its detent and the system locks up in that position. If the operator wants the master cylinder to extend further to a second limit position, he opens the solenoid-actuated valve and again operates the main control valve to extend the master cylinder. The system insures that the main control valve will be released from the detent position when the slave cylinder is fully extended at the first limit position of the master cylinder.

Abstract: This invention relates to a valve suitable for location within a passage or bore of a piston or piston rod of a hydraulic ram assembly. The valve includes a valve body mountable in the bore or passage and a chamber provided in the valve body having a pair of fluid access ports preferably having a relatively narrow outer passage and an enlarged inner space which may function as a valve seat. There is also provided a pair of valve members wherein each valve member may co-operate with a respective valve seat to close or open same to fluid flow through the valve chamber.

Abstract: A pressurized hydraulic fluid supply is arranged to supply hydraulic fluid to a plurality of rescue tools from a single power source through a series flow connector block so as to permit operation of two or more tools simultaneously.

Abstract: Piston rods of three linear hydraulic motors are connected at their outer ends to two spaced apart transverse frame members. A cylinder housing is driven back and forth along each pair of piston rods. Three transverse drive beams are provided. Each drive beam is directly connected to an associated one of the cylinder housings. Three sets of floor slat members are provided. Each set is connected to an associated one of the transverse drive beams. The linear hydraulic motors are operated for moving the floor slat members in one direction, for advancing a load, and for retracting them in an opposite direction. Each cylinder housing has four fluid chambers. First and third chambers are interconnected and the second and fourth chambers are interconnected. This arrangement provides adequate force producing area with a relatively small diameter cylinder housing. Fluid passageways are formed in the piston rods. Transfer valves are incorporated in end portions of some of the linear hydraulic motors.

Abstract: In a method of and device for adjusting the feed movement of a drill rod for drilling a rock, the drill rod is rotated by a pressure-medium-operated rotary motor and fed in a drilling direction and in the opposite direction by a pressure-medium-operated feed motor. A pressure change on the pressure side of the rotary motor due to a change in the rotation resistance on the rotary motor acts oppositely on the pressure and outlet sides of the feed motor toward reversing the feed force of the feed motor, i.e. in inverse and direct dependence on the pressure change, respectively. The pressures on the pressure side and the outlet side of the feed motor are, therefore, controlled so that, when the pressure on one side increases because of the pressure change, the pressure on the other side decreases and vice versa.

Abstract: A self-leveling series type hydraulic system including boom and bucket valves which separately control boom and bucket cylinders and a flow divider valve positioned in the exhaust flow path of the rod end of the boom cylinder. The flow divider valve splits the flow sending a portion of it to the cap end of the bucket cylinder so as to maintain the bucket in a level condition during raising of the boom with the remaining flow connected to one of the boom valve motor ports. An improved boom lower circuit which bypasses the flow divider valve as the boom is lowered to achieve a faster boom lower rate and the inclusion of an unloading valve in the bucket circuit which includes the dual function of preventing cavitation and relieving high pressure.

Abstract: A driving apparatus for producing a to-and-fro movement and having four plunger cylinders and four external non-return valves. Such driving apparatus is distinguished by a particularly simple construction.

Abstract: In a combine header having a rotatable crop reel, a hydraulic cylinder is carried on each of the reel support arms for adjusting the fore and aft position of the reel. The cylinders are serially connected and comprise a phasing circuit wherein the cylinders have paired fluid inlets and flow-restricting orifices, and the piston is positionable between the inlet and orifice of a pair in either full-strode position. A check valve is operationally associated with each orifice to prevent loss of fluid acting on the piston when being moved from either full-stroke position.

Abstract: A hydraulic feed control system for log debarkers having three infeed and three outfeed rolls. Each roll is driven by its own hydraulic motor. Each infeed motor is connected in series with a corresponding outfeed motor whereby three pairs of motors are defined. The hydraulic fluid is pumped through a three way flow divider which divides the fluid equally to each of these pairs. Each of the motors has a special crossover relief with a directional flow control that will prevent the excessive pressure that may be created by one of the motors in the series from effecting the pressure to the other motors. The special relief is also provided with a direct line into the oil reservoir which if needed either of the motors in series may siphon oil from the reservoir through the directional flow control valve without affecting the other motor. The return line from the outfeed (down flow) motor joins a common return which is separate from the relief return to tank.

Abstract: A hydraulically operated dockboard comprising a ramp which is hinged at its rear edge to the frame of the dockboard, and a lip is hinged to the forward edge of the ramp. A main hydraulic cylinder unit connects the frame and the ramp, and by operating the cylinder unit the ramp can be pivoted upwardly from a horizontal cross traffic position to an upwardly inclined position. A lip cylinder interconnects the ramp and the lip and acts to pivot the lip from a downwardly hanging pendant position to an extended position. A hydraulic line is connected to the lip cylinder, and a control valve interconnects the hydraulic line to either a supply line or a return line that is connected to the reservoir of the hydraulic system. The control valve is normally biased to a first position where the lip cylinder is connected to the return line.

Abstract: A hydraulic control circuit system comprises first and second double-acting cylinders, a hydraulic pump for supplying the double-acting cylinders with pressure oil, and directional control valves respectively associated with the cylinders for controlling the supply of pressure oil to the latter. The hydraulic control circuit system has a circuit for independently operating the individual cylinders and also a circuit for causing the rod advancing and retracting actions of the first cylinder to be followed by the rod advancing and retracting actions of the second cylinder. The system is applied to the hydraulic control circuit of, e.g., a front loader for controlling a hydraulic cylinder used for lifting and lowering the loader arm and another hydraulic cylinder used for turning the bucket pivotally connected to the free end of the arm.

Abstract: A hydraulic control arrangement comprises a first hydraulic ram, a second hydraulic ram, and a hydraulic control circuit associated with the first and second hydraulic rams. Each of the hydraulic rams has a cylinder, a piston reciprocable within the cylinder, and a piston rod fixed to the piston. Each of the hydraulic rams has a cylindrical working chamber and an annular working chamber positioned on opposite sides of its piston. The piston rod of each hydraulic ram constitutes the cylinder of a respective metering ram, a respective metering piston being reciprocable within the cylinder of each metering ram to define a metering chamber therewithin. The hydraulic control circuit includes a line, which interconnects the two metering chambers, and a hydraulic valve positioned in a hydraulic fluid supply line leading to the cylindrical working chamber of the second hydraulic ram.

Abstract: Apparatus and method for hydraulic actuation via multiple synchronized hydraulic motors with air purging, synchronizing, and force limiting features.

Abstract: An apparatus for the exact position feedback of a double-acting power piston in a hydraulic power cylinder subjected to extreme environmental conditions, especially high temperatures, comprising a double-acting detecting (measuring), or follower cylinder, having a volume corresponding to that of said power cylinder and including a detecting piston the position of which is sensed by an electrical detector, wherein a pair of working spaces of power and detecting cylinders are in fluid communication with each other via a connecting pipe, while the respective other working spaces are adapted to be connected to a (pressursized) fluid pump or a reservoir through a control valve.

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: A self-leveling series type hydraulic system with a float position including boom and bucket valves which separately control boom and bucket cylinders and a flow divider valve positioned in the exhaust flow path from the rod end of the boom cylinder. The flow divider valve in one position splits the flow sending a portion of it to the cap end of the bucket cylinder so as to maintain the bucket in a level condition during raising of the boom with the remaining flow returning to the control valve downstream of the boom valve whereby the bucket valve can be separately actuated concurrent with the boom valve and supplied with oil so as to override the self-leveling function if desired. The flow divider valve having a second position which bypasses all of the flow from the boom cylinder to reservoir when the boom control valve is in a float position.

Abstract: An hydraulic jack having more than two chambers is disclosed and is intended for use in a system of jacks, the displacement of which is to be synchronized. Each jack has a cylindrical center cavity in which a piston with a cylindrical cross section reciprocates, an annular cavity in which a piston with an annular cross-section reciprocates, and a rod for transmitting thrust connected to both pistons. In order to provide the jack with a minimum longitudinal dimension and with maximum rigidity, the two cavities are concentric and are separated by a stationary intermediate wall. The two pistons are connected to the rod for the transmission of thrust.

Abstract: A hydraulic circuit system of a construction machine having first and second hydraulic circuit, and a bypass circuit for connecting the first and second circuits together. The first circuit includes a first hydraulic pump and a first valve group having a plurality of directional control valves for controlling a flow of hydraulic fluid from the first pump, and the second circuit includes a second hydraulic pump and a second valve group having a plurality of directional control valves for controlling a flow of hydraulic fluid from the second pump. A plurality of actuators are driven by the hydraulic fluid supplied from the first and second pumps through the valves. The bypass circuit includes a bypass line for connecting the first travel valve in series with the second travel valve in a position downstream thereof through the selecting valve.

Abstract: The present invention relates to a device for controlling two fluid-controlled drive members, one of which is double-acting, wherein a communication conduit connects the supply conduits of said double-acting drive member, a non-return valve being disposed in said communication conduit and allowing the passage of the fluid solely from the small chamber towards the large chamber of said double-acting drive member, while another conduit is adapted to connect the large chamber of the double-acting drive member to the chamber of the second drive member. The result of the invention is the elimination of lift of a hydraulic loading shovel when digging.

Abstract: The double-acting hydraulic cylinders of the lift system are connected in a master-slave series relationship. When the cylinders have been retracted to a predetermined extent, a control valve between the last slave and a primary selector valve of the system is mechanically closed responsive to the arrival of the cylinders at such retracted condition and, simultaneously, the master is prevented from further retraction by either mechanical means or another hydraulic control valve between the master and the primary selector valve. Thus, the cylinders and their interconnecting lines are cut off from inadvertent overcharging, as well as fluid escape, so that all cylinders remain uniformly extended with drift from their established positions. Several circuit arrangements are disclosed, including provision for bleeding off higher than necessary operating pressures tending to become trapped within the cylinders and their associated flow lines after the cylinders have reached the intended point of retraction.

Abstract: A pneumatic throttle control configuration provides synchronized start-up and independent shut-off of multiple pneumatic tools. Each tool includes a throttle control assembly having a manually operable throttle valve which selectively admits air to the vane motor of the tool and a spring-biased piston operably coupled to the throttle valve which maintains it in an open position in response to air pressure in a control line which interconnects the tools. The vane motor includes a governor controlled valve which opens at a predetermined motor speed and provides air to the control line and the pistons of each tool of the multiple tool arrangement, thereby opening every throttle valve. Each pneumatic tool may then operate and stall independently. When the last tool stalls, the control air flow to all tools is terminated and the throttle valves close.

Abstract: A device in rock or earth drilling apparatus for rotary drilling including an axially stationary chuck (21) and an axially movable chuck (27) which is rotated by a reversible pressure fluid driven rotary motor (32) having a pressure fluid supply conduit for each direction and which is moved forwards and backwards by a reversible pressure fluid driven feed motor (17) having a pressure fluid supply conduit (18, 19) for each direction, the chucks being actuated to withdraw from or insert in a drill hole a drill string (23) composed by a number of threaded string elements and (are also actuated) to make or break the joints between the string elements.

Abstract: A concrete pump comprises a pair of separate pump assemblies each having a cylinder, a piston subdividing same into a piston-side front compartment and a rod-side rear compartment, and a piston rod connected to the respective piston and extending out of the respective cylinder through the respective rod-side rear compartment. The pump also has a liquid supply having a high-pressure side and a low-pressure side for supplying liquid under high pressure at the high-pressure side and for taking in liquid at the low-pressure side.

Abstract: A roof support unit for a longwall mineral mining installation has a roof shield supported above a floor sill. A first hydraulic ram is provided for advancing the roof support unit. The roof shield is provided with a forward extension which is advanceable by means of a second hydraulic advance ram. A hydraulic control arrangement, which includes the two hydraulic advance rams is provided for controlling the advance of the roof shield extension in dependence upon the working stroke of the first hydraulic advance ram. The control arrangement is such that the amount of hydraulic fluid supplied to one of the pressure chambers of the second hydraulic advance ram is dependent upon the amount of hydraulic fluid expelled from one of the pressure chambers of the first hydraulic advance ram during the working stroke of the first hydraulic advance ram.

Abstract: A pressure control mechanism for the hydraulic control system of a log skidder. Hydraulic circuits for the boom and the grapple of a log skidder are interconnected to provide a pressure control mechanism for the grapple of the skidder. Provided in the interconnecting hydraulic lines for the grapple cylinder and the boom cylinder, between the rod end of the boom cylinder and the base end of the grapple cylinder, is a two-way valve and a check valve. This mechanism provides flow from the boom cylinder to the grapple cylinder. The weight of the load pressurizes the boom cylinder and this pressure is transferred to the grapple cylinder.

Abstract: An implement frame (12) is supported by two pairs of laterally spaced wheels (36, 37 and 38, 39) whose vertical position relative to the frame is controlled by a pair of parallel master cylinders (61, 62) connected to one pair of wheels (36, 37) and a pair of parallel connected slave cylinders (63, 64) connected to the second pair of wheels (38, 39). The master and slave cylinders are series connected to provide even raising and lowering of the implement frame. The parallel connections between corresponding ends of the master and slave cylinders (61, 62, 63, 64) provide a walking beam effect with resulting equal loading on the wheels (36, 37, 38, 39).

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 hydraulic system is disclosed for use in an automotive vehicle including an engine, a power steering gear, and a brake booster. The system includes a single engine driven pump in fluid communication with first and second fluid flow control means. The first fluid flow control means responsive to fluid inputs for discharging a small or large predetermined amount of hydraulic fluid to control the operation of the power steering gear. The second fluid flow control means supplies a constant amount of hydraulic fluid to control the operation of the brake booster.

Abstract: A fluid actuator where an outside cylinder envelopes an inside cylinder producing four chambers, two for the power stroke and two for synchronization, for application where two or more cylinders are to drive a single load such that all cylinders advance at the same rate by cross plumbing synchronizing chambers. The combination is provided with valve means which opens at the end of each stroke to realign the actuators.

Abstract: A self-leveling series type hydraulic system including boom and bucket valves which separately control boom and bucket cylinders and a flow divider valve positioned in the exhaust flow path from the rod end of the boom cylinder. The flow divider valve splits the flow sending a portion of it to the cap end of the bucket cylinder so as to maintain the bucket in a level condition during raising of the boom with the remaining flow connected to one of the boom valve motor ports whereby the bucket valve can be separately actuated concurrent with the boom valve and supplied with oil so as to override the self-leveling function if desired.

Abstract: A hydraulic system for a round bale wagon is disclosed wherein at least two hydraulic cylinders are connected hydraulically in series. A relief valve redirects the flow of hydraulic fluid to continue the operation of subsequent hydraulic cylinders in the series circuit and to continue the flow of hydraulic fluid through the circuit when one of said hydraulic cylinders reaches the end of its stroke. The hydraulic cylinders corresponding to a bale pickup and the bale handling mechanism are connected in series in such a manner that, when the bale pickup is doing work in elevating a bale onto the load bed, the bale handling mechanism is returning to its home position without doing work and, when the bale pickup returns to its first position adjacent the ground, it does no work, while the bale handling mechanism works to arrange the deposited bales in a preselected position on the load bed.

Abstract: Cutting apparatus having a chain saw operated by a hydraulic motor as it is simultaneously moved towards an anvil by a hydraulic cylinder in a scissor cutting action. A valve is connected to the pressure line of the hydraulic cylinder to divert hydraulic fluid from said line to control the energization of the cylinder in accordance with the load put on the motor by the saw chain. This valve includes operating means to control the flow of fluid therethrough from zero to sufficient to stop the hydraulic cylinder. A line extends from the pressure line of the hydraulic motor to the valve operating means to increase and decrease the fluid flow through the valve respectively in accordance with increases and decreases of the pressure in the feed line of the motor inversely to control the pressure in the feed line of the cylinder.