Claims
- 1. Apparatus for effecting incremental drive of a hydraulic ram which includes a balanced piston, a first expansible chamber on one side of the balanced piston and a second expansible chamber on the opposite side of the balanced piston, said apparatus, comprising:
- a reversible positive displacement means operable in one direction to transfer hydraulic fluid from a first expansible chamber to a second expansible chamber, and operable in the opposite direction to transfer hydraulic fluid from a second chamber to a first chamber; and
- means for effecting incremental operation of said positive displacement means, comprising:
- hydraulic motoring means drivingly connected to said positive displacement means, said hydraulic motoring means comprising a plurality of cylinders, pistons within said cylinders, and means operable in response to sequenced pressurization of the cylinders, and attendant piston movement, to apply a driving force to said reversible positive displacement means;
- distributor valve means including a rotary control member and port means controlled by rotation of said rotary control member for communicating hydraulic pressure to a group of said cylinders which are in series while venting the rest of said cylinders to a return line;
- means for generating electrical digital command pulse signals; and
- an electric stepping motor operable by said electrical digital command pulse signals to rotate in increments, and including a rotary output connected to the rotary control member of the distributor valve means,
- with rotation of said rotary control member sequencing pressurization by progressively adding a cylinder to the forward edge of the pressurized group of cylinders and removing a cylinder from the trailing edge of the pressurized group of cylinders, to in that manner deliver driving pulses of hydraulic pressure to the hydraulic motoring means, with the pistons of each new group of pressurized cylinders functioning to drive the positive displacement means into a new position of equilibrium and then hold it in such position until there is another change in the make-up of the pressurized group of cylinders,
- whereby an increment of movement of the positive displacement means occurs in direct response to each command pulse that is received by the stepping motor, attended by an increment of fluid transfer and a corresponding increment of linear movement of the hydraulic ram.
- 2. Apparatus aboard an aircraft for positioning a component of the aircraft, capable of accepting a digital command, comprising:
- a balance piston linear hydraulic ram comprising a cylinder, a balanced piston within said cylinder dividing the cylinder into first and second expansible chambers on opposite sides of the piston; and
- means for incrementally driving said ram comprising:
- a reversible positive displacement pumping means operable in one direction to transfer hydraulic fluid from the first expansible chamber of said ram to the second expansible chamber of said ram, and operable in the opposite direction to transfer hydraulic fluid from the second chamber to the first chamber; and
- means for incrementally driving said rotary positive displacement pumping means, comprising;
- hydraulic motoring means drivenly connected to said positive displacement pumping means, said hydraulic motoring means comprising a plurality of cylinders, pistons within said cylinders, and means operable in response to sequenced pressurization of the cylinders, said attendant piston movement, to apply driving forces to pumping means;
- distributor valve means including a rotary control member and port means controlled by rotation of said rotary control member for communicating hydraulic pressure to a group of said cylinders which are a series while venting the rest of said cylinders to a return line;
- means for generating electrical digital command pulse signals; and;
- an electric stepping motor operable by said digital command pulse signals to rotate in increments, and including a rotary output connected to the rotary control member of the distributor valve means,
- with rotation of said rotary control member sequencing pressurization by progressively adding a cylinder to the forward edge of the pressurized group of cylinders and removing a cylinder from the trailing edge of the pressurized group of cylinders, to in that manner deliver driving pulses of hydraulic pressure to the hydraulic motoring means, with the pistons of each new group of pressurized cylinders functioning to drive the pumping means into a new position of equilibrium and then hold it in such position until there is another change in the makeup of the pressurized group of cylinders,
- whereby an increment of displacement occurs in direct response to each command pulse that is received by the stepping motor, attended by an increment of fluid transfer by the displacement means, and a corresponding increment of linear movement of the ram and an aircraft component positioned by it.
- 3. Apparatus according to claim 2, further comprising means for maintaining a predetermined desired average pressure level between the two sides of the ram piston, to maintain output stiffness of the ram.
- 4. Apparatus according to claim 3, wherein said average pressure maintance means comprises a regulating valve, and means operable in response to a fluid signal representing an average of the pressures on the opposite sides of the ram piston to meter flow from a supply pressure line to one of the expansible chambers and from the other expansible chamber to a return pressure line, to maintain the average pressure at a predetermined desired value.
- 5. Apparatus according to claim 4, wherein the regulating valve means comprises a slide member and port means controlled by axial movement of said slide member, a biasing spring acting on one end of the slide member, and two separate pressure surfaces at the opposite end of the slide member, wherein in use one of said surfaces is in communication with one of the expansible chambers and the other surface is in communication with the other expansible.
- 6. Apparatus according to claim 3 wherein said average pressure maintaining means comprises a four-way linear valve including a housing means defining metering ports, a port control member in said housing, and means responsive to the position of the rotary output of the stepping motor for positioning the port control member relative to said ports.
- 7. An electrohydraulic mechanism, comprising:
- an electric stepping motor operable by digital command signals to rotate in increments, and including a rotary output;
- pumping means comprising a plurality of cylinders, and pistons within said cylinders movable axially;
- hydraulic motoring means including a plurality of cylinders, pistons within said cylinders, and means operable in response to sequenced pressurization of the cylinders, and attendant piston movement, to apply driving forces to the pistons of said pumping means;
- distributor valve means including a rotary control member and port means controlled by rotation of said rotary control member for communicating hydraulic pressure to a group of said motoring means cylinders which are in series while venting the rest of said cylinders;
- means connecting the rotary output of the electric stepping motor to the rotary control member of the distributor valve means; and
- valve means for said pumping cylinders, communicating each pumping cylinder with a hydraulic fluid inlet port during retraction of the pistons and with an outlet port during extension of the pistons.
- 8. A mechanism according to claim 7, wherein said hydraulic motoring means comprises a cylinder block in which the motoring cylinders are formed, and wherein the distributor valve means is centrally located within said cylinder block.
- 9. Mechanism according to claim 7, wherein there is an equal number of pumping and motoring cylinders, the pumping and motoring cylinders extend axially of the mechanism and are arranged in a ring about the center line of the mechanism, and the pumping and motoring cylinders are coaxial, and wherein each motoring piston is joined with a pumping piston.
- 10. A mechanism according to claim 9, comprising a wobble plate connected at its periphery to said pistons, for coordinating movement of the pistons.
- 11. A mechanism according to claim 10 wherein said valve means comprises a rotating ported disc, a crank shaft for rotating said ported disc, and means connected to the wobble plate for driving the crank shaft.
- 12. Apparatus for effecting incremental drive of a balanced piston hydraulic ram, comprising:
- a balanced piston hydraulic ram having a first expansible chamber on one side of the balanced piston and a second expansible chamber on the opposite side of the piston;
- a reversible positive displacement means operable in one direction to transfer hydraulic fluid from the first expansible chamber to the second expansible chamber, and operable in the opposite direction to transfer hydraulic fluid from the second chamber to the first chamber; and
- means for effecting incremental operation of said positive displacement means, comprising:
- hydraulic motoring means drivingly connected to said positive displacement means, said hydraulic motoring means comprising a plurality of cylinders, pistons within said cylinders, and means operable in response to sequenced pressurization of the cylinders, and attendant piston movement, to apply a driving force to said reversible positive displacement means;
- distributor valve means including a rotary control member and port means controlled by rotation of said rotary control member for communicating hydraulic pressure to a group of said cylinders which are in series while venting the rest of said cylinders to a return line;
- means for generating electrical digital command pulse signals; and
- an electric stepping motor operable by said electrical digital command pulse signals to rotate in increments, and including a rotary output connected to the rotary control member of the distributor valve means,
- with rotation of said rotary control member sequencing pressurization by progressively adding a cylinder to the forward edge of the pressurized group of cylinders and removing a cylinder from the trailing edge of the pressurized group of cylinders, to in that manner deliver driving pulses of hydraulic pressure to the hydraulic motoring means, with the pistons of each new group of pressurized cylinders functioning to drive the positive displacement means into a new position of equilibrium and then hold it in such position until there is another change in the make-up of the pressurized group of cylinders,
- whereby an increment of movement of the positive displacement means occurs in direct response to each command pulse that is received by the stepping motor, attended by an increment of fluid transfer between the expansible chambers of the ram and a corresponding increment of linear movement of the hydraulic ram.
- 13. Apparatus according to claim 12, further comprising means for maintaining a predetermined desired average pressure level between the two sides of the ram piston, to maintain output stiffness of the ram.
- 14. Apparatus according to claim 13, wherein said average pressure maintenance means comprises a regulating valve, and means operable in response to a fluid signal representing an average of the pressures on the opposite sides of the ram piston to meter flow from a supply pressure line to one of the expansible chambers and from the other expansible chamber to a return pressure line, to maintain the average pressure at a predetermined desired value.
- 15. Apparatus according to claim 14, wherein the regulating valve means comprises a slide member, a biasing spring acting on one end of the slide member, and two separate pressure surfaces at the opposite end of the slide member, wherein in use one of said surfaces is in communication with one of the expansible chambers and the other surface is in communication with the other expansible chamber.
- 16. Apparatus according to claim 13, wherein said average pressure maintaining means comprises a four-way linear valve including a housing means defining metering ports and a port control member in said housing, and means responding to the position of the rotary output of the stepping motor for controlling the position of the port control member relative to said ports.
- 17. Apparatus according to claim 16, wherein said means responding comprises a crank arm connected to the rotary output of the rotary stepping motor and linkage means interconnected between the crank arm and said and said port control member.
GOVERNMENT INTEREST
The government has rights to this invention pursuant to Contract No. F33615-77-C-2034 awarded by U.S. Airforce.
US Referenced Citations (28)