US3601180A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure-casting machine
Assignee: Buehler AG
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Filing: 1969-09-24
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Granted: 1971-08-24
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Expires: 1989-09-24
Abstract
Abstract A pressure casting machine includes a chill mold, mold-closing means, a filling bush opening into the mold and a pressing ram displaceable in the filling bush. A hydraulic pressing unit is associated with the ram and includes a shot cylinder, a hydraulically operated shot piston, and a multiplier cylinder connected with the shot cylinder and having a multiplier piston which is hydraulically loadable on both sides and hydraulically connectable to the shot piston. An accumulator is chargeable by a pressure medium source, and hydraulic components interconnect the pressure medium source, the accumulator, the shot cylinder and the multiplier cylinder. A hydraulic line connects the multiplier cylinder, on the side of the multiplier piston facing the pressing ram, to the pressure medium source. An overflow valve is interposed in this line and is adjustable as to operating pressure. A controllable shutoff valve is connected to the overflow valve and acts as a precontrol for the overflow valve. The overflow valve is in the range of influence of the hydraulic pressure effective on that side of the shot piston facing away from the pressing ram. A switching device, operable in dependence on the pressure, is in controlling connection with the shutoff valve and operative to effect hydraulic connection of the multiplier piston and the shot piston in accordance with the operating pressure of the overflow valve and within the pressure range limited by the accumulator. The pressure-responsive control means may be purely hydraulic or may be a combination of electrically and hydraulically operated components.
Inventors
- 👤 Alfred Nef
- 👤 Siegfried Erhard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:39
CPC Classifications
B; B22; B22D; B22D17/00; B22D17/08; B22D17/10; B22D17/20; B22D17/32
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
246 words
In a pressure casting machine, for the casting of metal melts in chill molds, including mold closing means, a filling bush opening into the mold, a pressing ram displaceable in the filling bush and having a hydraulic pressing unit associated therewith, the pressing unit including a shot cylinder, a hydraulically loadable shot piston displaceable in the shot cylinder, and a multiplier cylinder correlated with the shot cylinder and having a multiplier piston displaceable therein, hydraulically loadable on both sides and hydraulically connectable to the shot piston, an accumulator hydraulically chargeable by a pressure medium source, and hydraulic components interconnecting the pressure medium source, the accumulator, the shot cylinder and the multiplier cylinder: the improvement comprising, in combination, a hydraulic line connecting said multiplier cylinder, on that side of said multiplier piston facing said pressure ram, to said pressure medium source; an overflow valve interposed in said hydraulic line and adjustable as to operating pressure; a controllable shutoff valve connected to said overflow valve and acting as a precontrol for said overflow valve, said overflow valve being in the range of influence of the hydraulic pressure effective on that side of said shot piston facing away from said pressing ram; and a pressure dependently operable switching device in controlling connection with said shutoff valve and operative to effect hydraulic connection of said multiplier piston to said shot piston in accordance with the operating pressure of said overflow valve and within the pressure range limited by said accumulator.
Claim 2
Dependent Claim
246 words
In a pressure casting machine, for the casting of metal melts in chill molds, including mold closing means, a filling bush opening into the mold, a pressing ram displaceable in the filling bush and having a hydraulic pressing unit associated therewith, the pressing unit including a shot cylinder, a hydraulically loadable shot piston displaceable in the shot cylinder, and a multiplier cylinder correlated with the shot cylinder and having a multiplier piston displaceable therein, hydraulically loadable on both sides and hydraulically connectable to the shot piston, an accumulator hydraulically chargeable by a pressure medium source, and hydraulic components interconnecting the pressure medium source, the accumulator, the shot cylinder and the multiplier cylinder: the improvement comprising, in combination, a hydraulic line connecting said multiplier cylinder, on that side of said multiplier piston facing said pressure ram, to said pressure medium source; an overflow valve interposed in said hydraulic line and adjustable as to operating pressure; a controllable shutoff valve connected to said overflow valve and acting as a precontrol for said overflow valve, said overflow valve being in the range of influence of the hydraulic pressure effective on that side of said shot piston facing away from said pressing ram; and a pressure dependently operable switching device in controlling connection with said shutoff valve and operative to effect hydraulic connection of said multiplier piston to said shot piston in accordance with the operating pressure of said overflow valve and within the pressure range limited by said accumulator.
Claim 3
Dependent Claim
48 words
In a pressure casting machine, the improvement claimed in claim 1, in which said switching device includes means operable to reduce the pressure controlling said shutoff valve, and which is simultaneously effective on said shot piston, by a predetermined magnitude below the pressure then prevailing in said accumulator.
Claim 4
Dependent Claim
108 words
In a pressure casting machine, the improvement claimed in claim 1, in which said switching device controls said shutoff valve with a time delay for reversal of said shutoff valve; a second hydraulic line connecting the pressure medium admission of said shot piston and said shutoff valve; throttle means interposed in said second hydraulic line; a branch line connecting said second hydraulic line to said accumulator; a pressure vessel interposed in said branch line; and a mechanical separating member movable in said pressure vessel; said mechanical separating member being subjected to the pressure prevailing in said accumulator as well as to the pressure effective on said shot piston.
Claim 5
Dependent Claim
30 words
In a pressure casting machine, the improvement claimed in claim 3, in which said switching device controls said shutoff valve with a variable time delay; said throttle means being adjustable.
Claim 6
Dependent Claim
50 words
In a pressure casting machine, the improvement claimed in claim 3, in which said switching device controls said shutoff valve with a variable time delay; said mechanical separating member comprising a piston displaceable in said pressure vessel; and means adjustably limiting movement of said last-named piston in said pressure vessel.
Claim 7
Dependent Claim
33 words
In a pressure casting machine, the improvement claimed in claim 3, including a pressure reducing member, having a constant pressure drop, interposed in said branch line between said pressure vessel and said accumulator.
Claim 8
Dependent Claim
48 words
In a pressure casting machine, the improvement claimed in claim 1, in which said controllable shutoff valve is an electrically controllable shutoff valve; said switching device including a hydraulic pressure operated electric switch controlling said shutoff valve as a function of the pressure effective on said shot piston.
Claim 9
Dependent Claim
41 words
In a pressure casting machine, the improvement claimed in claim 7, in which said switching device controls said shutoff valve with a variable time delay; said switching device including an electric time delay circuit in controlling relation with said shutoff valve.
Claim 10
Dependent Claim
91 words
In a pressure casting machine, the improvement claimed in claim 7, including at least one electric excitation regulator for said switch-off valve; said hydraulic pressure operated switch being effective, in one position, to connect said regulator in effective controlling relation with said shutoff valve and, in another position, to disconnect said regulator from effective controlling relation with said shutoff valve; said excitation regulator and said hydraulic pressure operated electric switch providing for the control of at least one overflow pressure to be effected by said shutoff valve in said overflow valve.
Claim 11
Dependent Claim
79 words
In a pressure casting machine, the improvement claimed in claim 9, including two adjustable excitation regulators operatively associated with said shutoff valve; said hydraulic pressure operated electric switch being effective to selectively connect a selected one of said adjustable excitation regulators to said shutoff valve; connection of one excitation regulator to said shutoff valve effecting blocking of said multiplier piston, and connection of the other excitation regular to said shutoff valve controlling the magnitude of the multiplier after pressure.
Claim 12
Dependent Claim
73 words
In a pressure casting machine, the improvement claimed in claim 1, including a second hydraulic line connecting said shot cylinder, on that side of said shot piston facing said pressure ram, to said pressure medium source; a third hydraulic line connecting said first-mentioned hydraulic line to said second hydraulic line; and a check valve interposed in said third hydraulic line and blocking flow from said first-mentioned hydraulic line to said second hydraulic line.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-23 | 1975-02-22 | 1975-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-23 | 1979-02-22 | 1979-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-23 | 1983-02-22 | 1983-08-24 | $7700.00 | Window Closed / Lapsed |