Method and apparatus for hydraulic pressing
AssigneesS.I.T.I. Societa Impianti Termoelettrici Industriali S.p.A., Ulrico Walchhutter
InventorsUlrico Walchhutter, Renato Bossetti
Life of this patent
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Abstract
In a hydraulic circuit a positive-displacement pump has a flywheel. An actuation motor is attached to the positive displacement pump. The pump is capable of directing liquid flow either towards the tank or towards a hydraulic cylinder. The control of flow direction is determined by a first valve which is connected on the output side of the pump in order to discharge the flow of the positive displacement pump either to the tank or to the cylinder. The opening speed of the first valve is controlled. A bistable valve feeds the pilot line of the first valve. A distribution valve, connected with the output side of the pump feeds two pressure lines.
Claims43
A hydraulic circuit for feeding a pressurized liquid flow to hydraulic actuation means by means of check valve means open towards said hydraulic actuation means, comprising:
- a positive-displacement pump which has a flywheel for storing kinetic energy;
- an actuation motor for said positive-displacement pump;
- first valve means for discharging to a tank a liquid flow from said positive-displacement pump so that said hydraulic actuation means are actuated by closing said first valve means;
- and
- control means to control a speed of an opening stroke of a poppet of said first valve means;
- wherein said flywheel accumulates kinetic energy during opening of said first valve means and yields kinetic energy during closing of said first valve means.
A hydraulic circuit for feeding a pressurized liquid flow to hydraulic actuation means, comprising:
- a positive displacement pump which has a flywheel for storing kinetic energy and which operates with a direction of flow directed towards a delivery line;
- an actuation motor for said positive-displacement pump;
- first valve means for discharging to a tank a liquid flow from said positive-displacement pump;
- a poppet for said first valve means which is slidable inside a seat, so as to close a liquid passage opening with a force which is generated by a pilot pressure of a pilot line;
- and
- two inputs for said pilot line which are connected one to a hydraulic accumulator and the other one to said delivery line, the input at higher pressure determining said pilot pressure;
- wherein said hydraulic actuation means are actuated by closing said first valve means;
- and
- wherein said flywheel accumulates kinetic energy during opening of said first valve means and yields kinetic energy during closing of said first valve means.
A hydraulic circuit for feeding a pressurized liquid flow to hydraulic actuation means comprising:
- a positive-displacement pump which has a flywheel for storing kinetic energy and which operates with a direction of flow directed towards a delivery line;
- an actuation motor for said positive-displacement pump;
- first valve means for discharging to a tank a liquid flow from said positive-displacement pump;
- a remotely controllable distribution valve unit connected with said delivery line;
- and
- a plurality of pressure lines connected with said distribution valve unit;
- wherein said hydraulic actuation means are actuated by closing said first valve means;
- wherein said flywheel accumulates kinetic energy during opening of said first valve means and yields kinetic energy during closing of said first valve means;
- and
- wherein one of said pressure lines is connected with said hydraulic actuation means.
Dependencies are inferred from the claim text.