Showing papers on "Hydraulic machinery published in 1975"

Rotary cutting blade control system

Abstract: A rotary cutting blade control system which automatically varies the feed rate to maintain a constant material removal rate. The system senses the current in an electric motor driving the cutting blade and automatically adjusts the feed rate to maintain the motor current constant. The system adjusts a hydraulic valve in the hydraulic system operating the blade support to move the blade in or out whenever the current deviates from a standard which is set by the operator. The control system also includes a circuit for detecting when the load on the blade has dropped below a preset level indicating that the blade has completed the cut and automatically commands the hydraulic system to return the blade to a start position. An additional control circuit operating in conjunction with the no-load sensing circuit automatically produces a command to stop the blade close to the work piece to save time and motion when multiple cuts are being performed. This circuit operates by establishing a reference level indicating the position of the blade at the start of a cut.

Power source for subsea oil wells

Abstract: Disclosed are methods and apparatus for generating electric and hydraulic power adjacent an undersea oil well for use in operating the well-head equipment. The difference in the temperature of the oil being extracted from the well and the temperature of the surrounding sea water is utilized to generate such power.

Material transfer mechanism

Abstract: An improved material transfer mechanism comprising a selectively variable speed hydraulic power assembly having an output connected to and powering a material conveyor. A double acting hydraulic ram positions a swash plate control lever that determines the rotational speed of the output shaft, and a hydraulic porting valve assembly is disposed to actuate the hydraulic ram, the hydraulic porting valve assembly comprising a pivotally supported valve body having an internally disposed fluid control means, the fluid control means being variably displaced in the valve body by the actuation of a pressure controlling mechanism for the purpose of selectively determining and establishing fluid communication of a source of hydraulic pressure fluid to alternate ends of the hydraulic ram with the hydraulic porting valve assembly to selectively control the hydraulic ram. The valve body is biased in a first pivotal direction and is movable in a second pivotal direction by a feed back linkage cable interconnecting the valve body and the swash plate control lever. A sensor mechanism detects the material transferred by the material conveyor and responsively positions the pressure controlling mechanism independently to the position of the valve body.

Versatility of hydraulic systems

Abstract: The use of fluid or easily deformable materials for force transmission in a variety of animals is reviewed and its role in muscular antagonism is shown. The hydraulics of cells and developing embryos is mentioned and animals employing hydraulic systems are classified as having open, closed or external fluid compartments and simple or complex muscular arrangements. The importance of hydraulically antagonized muscle systems in movement and locomotion is described, and the application of force to the substratum discussed, including the concentration of force from a large muscle field on a smaller area of application. The jet propulsion of cephalopods and medusae is described and their short time scale of action is compared with the long time scale of operation of other hydraulic systems. The pumping operation of the nematode pharynx, the mechanism of suctorial feeding in insects and the energetic demands of tube irrigation in feeding are outlined.

Small hydraulic structures

Abstract: Small hydraulic structures , Small hydraulic structures , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Hydraulic damping means for hinged check valve

Abstract: An improved hydraulic control means for check valves to prevent slamming of a clapper against a seat. The clapper of the check valve is connected via a crosshead to an hydraulic cylinder and a piston contained therein controls the closing of the check valve. The hydraulic cylinder has means restricting flow of fluid from below the piston in the hydraulic cylinder to above the piston in the hydraulic cylinder, but permits unrestricted flow in the opposite direction. Relief valves are included to prevent overpressurization in the hydraulic cylinder. A precharged accumulator allows for fluid expansion and contraction in the hydraulic cylinder, plus replacing fluid lost by leakage.

Differential pressure visual and audible warning signal device for hydraulic and pneumatic systems

Abstract: A combination visual and audible differential pressure warning signal device for fluid power, that is, hydraulic and pneumatic systems such, for example, as those employed in mobile equipment, industrial machinery, or the like. Thus, in a typical use of the invention, when the pressure in the hydraulic system, as in an oil filter, drops below a desired and predetermined normal, due to clogging of the filter, or for other reasons, the hydraulic pressure from the source, such as an oil pump, overcomes the combined pressure or force of the oil entering the signal device from the filter and the force of a resetting coil spring in the signal device, to actuate magnetic means which raises a normally concealed colored (red) visual warning signal into a position in which it may be seen through a window in the body of the signal device while, at the same time, closing an electrical circuit to an audio or audio-visual warning signal device. Both the visual signal and the audio or audio-visual signals remain in actuated position until the difficulty in the oil filter, or the like, is corrected, and the hydraulic pressure in the system, as from an oil filter, is restored to normal, whereupon the force of the resetting coil spring, in conjunction with the force of gravity, returns the parts to their normal position, thereby moving the colored visual signal to its normal concealed position while, at the same time, breaking the electrical circuit to the audio or audio-visual signal device.

Hydraulic system for controlling a gang of lawn mowers

Abstract: A hydraulic system for controlling a gang of lawn mowers including a hydraulic pump and a multi-section valve and hydraulic motors driving the mowers Hydraulic cylinders are also included in the system, for raising and lowering the mowers, and a check valve is connected with the cylinders for controlling the lowering of the mowers The main valve is arranged with a plurality of spools which control the aforementioned functions and with the spools being set by means of a single handle so that the operator can perform the aforementioned functions through maneuvering the single handle for each set of hydraulic motors and cylinders A hydraulic flow restrictor is included in the system for reversing the motors at a speed slower than the forward motor speed, for a slower reverse rotation of the mowers, such as for back-lapping of the mowers

Supplemental oil system for engines

Abstract: An oil replenishment system provides a remote reserve oil tank and the plumbing necessary to fill the main oil tank or tanks of engines, especially aircraft engines during flight. This system includes apparatus to determine the quantity of oil pumped to any one engine so that a quantity gauge is not required on the engine. A selector valve located on the reserve tank which may be remotely controlled directs replenishment oil to the selected engine tank. The system is designed to be powered from the existing on board hydraulic power system.

Hydraulic system combining open center and closed center hydraulic circuits

Abstract: A hydraulic system is provided in which a single variable displacement pump supplies the hydraulic fluid requirements of both an open center hydraulic circuit and a closed center hydraulic circuit. The hydraulic output from the variable displacement pump is delivered to a pressure compensated flow divider which at all times delivers a priority minimum and constant flow to the open center hydraulic circuit despite variations in pump output pressures. Unless there is a demand for hydraulic flow by a device or devices in the closed center hydraulic circuit, there is no hydraulic flow delivery from the flow divider to the closed center hydraulic circuit, and the variable displacement pump operates at relatively low power input required to supply the demands of the open center hydraulic circuit. Particularly when the only hydraulic demand on the pump is to satisfy the requirements of the open center hydraulic circuit in neutral position, the pump can operate on a "standby" basis at a relatively low output pressure, such as 300 pounds per square inch, with consequent low input power to the pump, and with relatively low "wear and tear" on the pump. The variable displacement pump assembly comprises a hydraulically actuated stroke control means including a tiltably adjustable swash plate, and a hydraulic compensator for controlling the tilt of the swash plate. A first pilot circuit is permanently connected between the open center hydraulic circuit and the control input point of the hydraulic compensator which controls the angular position of the tiltably adjustable swash plate, whereby the output pressure of the pump may respond to changes in hydraulic pressure requirements in the open center hydraulic circuit. A second pilot circuit is connected at one of its ends to the hydraulic conduit which connects the flow divider to the closed center hydraulic circuitry, the opposite end of the second pilot circuit being connected to the control input point of the aforementioned compensator which controls the angular position of the tiltably adjustable swash plate. The second pilot circuit is completed to communicate a hydraulic input signal to the compensator from the closed center hydraulic circuit only in response to the actuation of at least one closed center device requiring hydraulic flow. Completion of the second pilot circuit as just mentioned will supersede the first pilot circuit whereby to cause the compensator to readjust the tiltably adjustable swash plate to cause the pump to supply the substantially higher hydraulic pressure requirements, such as 3,000 pounds per square inch, of the closed center hydraulic system.

Compound steering system for endless-track vehicles

Abstract: The driven sprockets of a pair of endless tracks on opposite sides of a vehicle are coupled with an engine by way of a hydraulic torque converter and a reversible transmission, the latter including two differential-gear sets with secondary inputs which can be rotated in mutually opposite directions by a steering unit comprising a mechanical and a hydraulic power train linked by two cascaded planetary-gear sets. The hydraulic power train receives torque directly from the engine whereas the mechanical power train is driven by the output of the torque converter to provide intensified steering action when, on downhill driving, the turbine of the converter outruns its impeller. The mechanical power train includes a pair of reversing clutches nested within a pair of similar clutches of the reversible transmission.

Automatic control means for infinitely variable transmission

Abstract: This invention describes a system of control for a power source-transmission-load system such as might be used on an off-the-road vehicle, for example. The power source is an internal combustion engine having a known optimum characteristic of desired manifold vacuum versus engine speed. The transmission is a hydrostatic or hydromechanical transmission having infinitely variable speed ratio and having a control means for varying said speed ratio. The control system includes a transducer means for measuring engine speed and converting this quantity into an analog fluid pressure proportional to the speed. This analog fluid pressure proportional to speed is modified in a function generator to produce an analog fluid pressure which is proportional to the desired manifold vacuum as a function of engine speed. Means are provided for measuring the actual manifold vacuum and for comparing the actual manifold vacuum with the desired manifold vacuum on a continuous basis. This comparison produces an error signal which is amplified and used to control a hydraulic system to operate the control means in order to vary the transmission ratio of the hydrostatic or hydromechanical transmission to obtain a speed ratio such that will provide optimum engine conditions.

Underwater trenching and cable laying apparatus

Abstract: A sled supports a hydraulic motor drive digging wheel in the bottom of a body of water with a cable guide conduit feeding cable into the trench behind the wheel; hydraulic cylinders adjust the depth of the trench with all means being controlled from a support barge or the like providing hydraulic power and control fluid.

Automatic control device for the distribution of hydraulic fluid between two hydraulic circuits

Abstract: In a hydraulic power system having two independent circuits, wherein one circuit has priority over the other circuit, and the priority circuit furnishes a residual flow to the non-priority circuit, a pressure sensing system is provided in the return flow line of the non-priority circuit which causes a directional flow valve to shift and direct the residual flow back to the priority circuit in the event of a leak in the non-priority circuit which results in a loss of pressure in the return line.

Energy conservation apparatus for an electric vehicle

Abstract: A hydraulic accumulator is provided in the hydraulic system of an electric vehicle, such as a lift truck, for conserving its battery power by minimizing the frequency of energy draining pump start-ups during operation. Pressurized fluid stored in such accumulator is utilized for powering any of the various hydraulically actuated work elements employed on the vehicle when the pump is not being run. The system further provides for automatically starting and stopping the pump to keep the pressure in the accumulator within a predetermined operating range and for starting the pump when required to achieve the desired actuation of a particular work element.

Hydraulic system for a working machine

Abstract: A hydraulic system for a working machine of the vehicle type having a power steering mechanism and a hydraulically powered working implement, such as a back-hoe implement. A hydraulic valve is inclined in the power steering mechanism, and another hydraulic valve operates the powered implement. A flow control valve divides flow between the aforementioned two valves, and a pump supplies the flow in the system. Pressure relief valves are included in the system, such that one relief valve senses pressure in the power steering branch of the system, and that relief valve responds to the lowest hydraulic pressure, and a relief valve for the powered implement responds to a higher hydraulic pressure. Only a single hydraulic pump is required for the power steering and the powered implement.

Automatic control circuit for an electrically powered hydraulic pump

Abstract: An emergency hydraulic system for use in a vehicle having an engine which not only powers the vehicle but also drives a main hydraulic pump to supply hydraulic fluid under pressure to a hydraulic control means is disclosed. The emergency hydraulic system includes an auxiliary hydraulic pump driven by an electric motor to provide an auxiliary source of hydraulic fluid under pressure to the hydraulic control means under emergency conditions. An electrical control circuit for the electric motor is described which control circuit will automatically activate the electric motor whenever the engine is operating normally but the flow of hydraulic fluid from the main hydraulic pump falls below a given level and will automatically inactivate the electric motor whenever the engine is operating normally and the flow of hydraulic fluid from the main hydraulic pump is above a given level. As disclosed, the control circuit also includes means for the manual operation thereof and means for automatically activating the electric motor only if the engine of the vehicle should fail after it has been in normal operation.

Priority steer system--hydraulic

Abstract: A hydraulic system for an electric-powered vehicle, such as a lift truck or the like, supplies pressurized fluid for a hydraulic steering system for the vehicle and for hydraulic motors for manipulating the implements of the vehicle, and includes a priority system for directing all fluid flow from the pump to the steering system circuit until a predetermined minimum pressure is achieved therein, after which fluid is made available to the implement circuit. These are provided in the system for automatically cutting off the electric motor for powering the pump of the system when no demand is made on the hydraulic system.

Control systems for variable capacity hydraulic machines

Abstract: A hydraulic machine is provided with a control for reducing the capacity of the machine when subjected to excessive pressure. A piston is slidable in a cylinder to define two chambers, the chambers being interconnected by a restrictive passage. One chamber is connected to the pressure line and the other chamber is connected to a relief valve so that in the steady state the pressure in each is equal. When the pressure reaches a predetermined level the relief valve opens and vents the other chamber. The passage prevents flow to the other chamber creating a pressure differential which causes the piston to move along the cylinder and operate the machine control to decrease the capacity thereof.

Load sensitive hydraulic system

Abstract: A load sensitive hydraulic system for operating auxiliary equipment on a vehicle with a priority flow control valve to provide priority pressure in operating a regenerative steering circuit of the hydraulic system. The regenerative hydraulic steering circuit provides load sensing and utilizes single source of pressurized fluid which responds to various loads in the hydraulic system. A priority valve assures that the steering demands are met before providing adequate pressure for all other auxiliary functions.

Hydraulic drill, in particular a rock drill

Abstract: A hydraulic rock drill having a hydraulic drill drive motor, a hydraulic feed motor, and a hydraulic impact unit and associated pumps for supplying hydraulic fluid under pressure and provided with an automatic control system including a valve controlling the flow to the impact unit under the dependence of the pressure in the rotation motor circuit such as to reduce the power of the impact unit when the pressure in the drive motor circuit exceeds a permissible pressure and vice versa. Additionally, the hydraulic system preferably includes an additional flow control valve such as to decrease the feed power when the impact power increases.

Throttle control mechanism for an engine

Abstract: The throttle of an engine is controlled to maintain its speed substantially constant in spite of variations of load upon it. The illustrated load comprises hydraulically operated equipment in a hydraulic system powered by a pump driven by the engine. Throttle control mechanism comprises a pair of cylinders supplied from fluid pressure in the hydraulic system. Pistons in the respective cylinders are connected by pivots with a control arm linked to the throttle control. When equipment is hydraulically operated from the hydraulic system, the fluid back pressure against the pump increases, this back pressure being greater the greater the hydraulic load. The increased load on the engine from the pump would slow the engine down if its throttle opening were to remain at its original setting. The function of the throttle control mechanism operated from the hydraulic pressure from the pump, is to move the control arm by a proper amount to open the throttle a sufficient amount to keep the engine speed up to its normal value regardless of changes of load. Compression springs adjustable from adjustable bushings at the cylinders provide a counter-pressure opposing the pressure from the fluid in the cylinders and by suitable adjustment of these bushings the throttle can be made to open or close further in accordance with changes of load to maintain substantially constant engine speed which will maintain uniform flow of fluid through the hydraulic system regardless of load thereon.

Hydraulic system for vehicle mounted snowplow blade

Abstract: A hydraulic system for a vehicle mounted snowplow blade capable of lifting, lowering, and angling the blade right or left has a single 4-way valve controlling power flow to the lift and angling cylinders. Power flow to and return flow from the angle cylinders is controlled through the 4-way valve. Power flow to the lift cylinder is controlled through the 4-way valve and return flow from the lift cylinder to the reservoir is controlled through a separate two-way valve. Both valves are electrically operated by means of solenoids connected directly to the valve body.

Control system for an integral spring-loaded parking and service brake

Abstract: A control system for a spring-applied service brake which can also be used as a parking brake. Pressure from the vehicle hydraulic system is normally used to release the brakes. In the event of a loss of the primary pressure from the hydraulic system, the control system switches automatically to use of secondary pressure from the vehicle compressed air system to release the brakes, while maintaining the ability of the operator to apply the brakes by normal operation of the service and parking brake controls.

Hydraulic rock drill system

Abstract: In a hydraulic percussion rock drill the operation of the working fluid distributing valve is controlled to effect a variation in percussive blow energy and blow frequency by varying the piston hammer stroke. Actuation of the distributing valve is controlled by a remote controlled hydraulically actuated pressure control valve interposed in a fluid passage which conducts hydraulic fluid from the hammer bore to actuate the distributing valve. Substantially infinite variation of hammer impact blow energy between high and low limits provides for selecting the maximum penetration rate of the drill for any type of rock conditions. The hydraulic rock drill is connected to a source of hydraulic fluid supplied to the drill at substantially constant fluid power by a variable displacement constant power hydraulic pump.

Spray control system

Abstract: The control system is utilized in a high pressure liquid spraying system including an internal combustion engine, a pump driven by the engine, a source of liquid connected to the pump and a spray nozzle assembly connected by a high pressure conduit to the output of the pump. The control system includes an enclosure and a valve assembly mounted near the pump. The valve assembly is operated by an electric switch mounted on the nozzle assembly and connected to a first solenoid valve in a hydraulic system for operating the valve assembly. The valve assembly includes a hydraulic cylinder which is mounted on the enclosure and which has a plunger positioned to open a ball valve of the valve assembly which is mounted within the enclosure and which is connected to the output of the pump. At engine idle, the first solenoid valve supplies engine oil pressure to the hydraulic cylinder whereby the plunger is urged against the ball valve to open the same to permit water to be dumped, with the enclosure cushioning the discharge of water from the ball valve. The control system also includes a second solenoid valve in a hydraulic system including a cylinder for advancing the engine throttle to increase the pressure of the water being pumped. At engine idle, this second solenoid valve connects the throttle advancing cylinder to an engine oil return manifold. Operation of the electric switch causes the first solenoid valve to connect the hydraulic cylinder to the engine oil return manifold whereby the ball valve can close so that pressurized water is supplied to the spray nozzle assembly. Operation of the switch also causes the second solenoid valve to connect the throttle advancing cylinder to engine oil pressure to accelerate the engine to increase the water pressure.

Powered lawn mower hydraulic system

Abstract: A powered lawn mower hydraulic system for use with a reel type of mower. The system includes a hydraulic pump and a hydraulic motor and a hydraulic valve, all interconnected with hydraulic hoses or lines. The valve permits reversing of the direction of rotation of the motor which is driving the mower reel, and there is a hydraulic flow restrictor in the reversing line for limiting the speed of the motor, and thus the mower, in the reversing direction. Also, there is shown a relief valve for limiting the hydraulic pressure in the reversing mode, and there is also shown a relief valve for limiting the hydraulic pressure in the forward mode.

Hydraulic system and automatically shiftable direction control valve therefor

Abstract: An improved automatically shiftable direction control valve for a tractor hydraulic system wherein there is provided a charging pump, low pressure priority functions such as cooling and lubrication connected to the charging pump, a main pump, a continuously acting reversible function, a single-acting function, and a double-acting function all connected to the output of the main pump, and a manually operable direction control valve for each of the functions. The improved automatically shiftable direction control valve has a restricted passage causing a pressure drop which shifts the valve so as to direct the exhaust of the continuously-acting and double-acting functions to the charging circuit and to direct the exhaust of the single-acting function to the fluid reservoir.

Downshift control circuit for hydraulic transmission

Abstract: A downshift control circuit including a self-holding element is coupled through an electrohydraulic transducer to the hydraulic power transmission of a road vehicle to supply thereto a downshift signal in the form of fluid. The self-holding element is operated upon depression of the brake pedal and released upon depression of the accelerator pedal. The electro-hydraulic transducer is operated by the self-holding element to apply said downshift signal once the brake pedal is depressed so that shifting point is moved to a higher speed to effect a downshift to the next lower speed. With the transmission gear at low, the braking effort of the engine is utilized to the fullest extent as an aid to the normal braking.

Hydraulic articulation system for tramway coach - actuates pivot point in proportion to the relative rotation of bogies

Abstract: Both coach halves are pivoted relative to each other about a vertical axis formed by pivoting pins in the frame and in the roof. A hydraulic system is used to maintain the stability of the articulated coach on travelling over the crossing switches and track bends. This arrangement ensures that the free sinusoidal lateral movements of the bogies are not transmitted to the pivoting elements. Each of the bogies has hydraulic cylinders whose pistons are connected with the bogie frame or the cradle. The rotating of the coach halves relative to each other about a vertical joint is caused by cylinder. Both sets of hydraulic cylinders are connected to each other by pipes so that two hydraulic systems are formed.