Patent US4022269A successfully refreshed from Google Patents.
US4022269A
Expired / Lapsed
US
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Die cast machines
Assignee: Shibaura Machine Co Ltd
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Filing: 1976-07-23
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Granted: 1977-05-10
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Expires: 1996-07-23
Abstract
Abstract In a die cast machine of the type wherein the piston of an injection cylinder is advanced by pressure gas admitted into the rear chamber of the cylinder while discharging pressurized liquid in the fore chamber, and the piston is retracted by pressurized liquid admitted into the fore chamber while forcing the gas in the rear chamber back into a gas accumulator, a control valve device is provided in the path of the pressurized liquid discharged from the fore chamber, and the control valve device is controlled so as to vary the flow quantity of the discharged pressurized liquid in accordance with the position of the piston during its forward movement. There are also provided two gas accumulators which are connected to the rear chamber of the cylinder through a valve device which is controlled so as to adjust the rate of increase of the pressure applied to the molten metal at the final stage of the injection casting operation.
Inventors
- 👤 Kazuyoshi Segawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:30
CPC Classifications
B; B22; B22D; B22D17/00; B22D17/20; B22D17/32
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
220 words
In a die cast machine including an injection cylinder and a piston contained therein for operating an injection plunger for injecting molten metal into a mould cavity, said piston dividing the interior of said cylinder into a fore chamber and a rear chamber, means for admitting pressurized gas from gas accumulator means into said rear chamber for advancing said piston and said injection plunger for injecting the molten metal into said mould cavity, and means for admitting pressurized liquid into said fore chamber to retract said piston thereby forcing the gas in said rear chamber back into said gas accumulator means, the improvement which comprises a control valve means connected in the discharge path of said pressurized liquid from said fore chamber, means for controlling the flow quantity of the pressurized liquid dicharged from said fore chamber and flowing through said control valve means in accordance with the position of said piston during the forward movement threof, thereby varying the speed of said piston, a plurality of gas accumulators, rear valve means connected between the rear chamber of said injection cylinder and said plurality of gas accumulators, and means for controlling said rear valve means so as to adjust the rate of increase of the pressure applied to the molten metal at the final stage of the injection casting operation.
Claim 2
Dependent Claim
220 words
In a die cast machine including an injection cylinder and a piston contained therein for operating an injection plunger for injecting molten metal into a mould cavity, said piston dividing the interior of said cylinder into a fore chamber and a rear chamber, means for admitting pressurized gas from gas accumulator means into said rear chamber for advancing said piston and said injection plunger for injecting the molten metal into said mould cavity, and means for admitting pressurized liquid into said fore chamber to retract said piston thereby forcing the gas in said rear chamber back into said gas accumulator means, the improvement which comprises a control valve means connected in the discharge path of said pressurized liquid from said fore chamber, means for controlling the flow quantity of the pressurized liquid dicharged from said fore chamber and flowing through said control valve means in accordance with the position of said piston during the forward movement threof, thereby varying the speed of said piston, a plurality of gas accumulators, rear valve means connected between the rear chamber of said injection cylinder and said plurality of gas accumulators, and means for controlling said rear valve means so as to adjust the rate of increase of the pressure applied to the molten metal at the final stage of the injection casting operation.
Claim 3
Dependent Claim
95 words
The die cast machine according to claim 1 wherein said rear chamber is connected to a low pressure gas accumulator through a check valve permitting gas flow from said low pressure gas accumulator to said rear chamber, a high pressure gas accumulator is connected to said low pressure gas accumulator via a pressure reducing valve, said rear chamber is connected to said high pressure gas accumulator through a check valve permitting gas flow from said rear chamber to said high presssure gas accumulator and through serially connected gas interception valve and a flow control valve.
Claim 4
Dependent Claim
85 words
The die casting machine according to claim 1 wherein a small gas accumulator is connected directly to said rear chamber, a large gas accumulator is connected to said rear chamber via a gas interception valve, said small and large gas accumulators are interconnected through a check valve permitting gas flow said small gas accumulator to said large gas accumulator, and said gas interception valve is operated in accordance with the gas pressure in said small gas accumulator and the liquid pressure in said fore chamber.
Claim 5
Dependent Claim
19 words
The die casting machine according to claim 3 wherein said gas interception valve is provided with flow control means.
Claim 6
Dependent Claim
79 words
The die casting machine according to claim 1 wherein said control valve means comprises a direction transfer valve having a first passage for supplying pressurized liquid to said fore chamber of the cylinder, and second and third passages having different flow rate for passing the pressurized liquid discharged from said fore chamber and means to switch the transfer valve from one passage to the other, and a flow contol valve connected in series with said second or third passage.
Claim 7
Dependent Claim
111 words
The die cast machine according to claim 1 wherein said control valve means comprises a first transfer valve having a first passage for supplying pressurized liquid to said fore chamber and a second passage for passing the pressurized liquid discharged from said fore chamber and means for swtiching said first transfer valve between said first and second passages, a pilot check valve connected to said fore chamber to discharge the pressurized liquid therefrom at a higher rate than said second passage of said first transfer valve, and a second transfer valve which is operated when said piston reaches a predetermined position during its forward movement for opening said pilot check valve.
Claim 8
Dependent Claim
29 words
The die cast machine according to claim 6 wherein said pilot check valve is provided with means for adjusting maximum speed of said piston during the forward movement thereof.
Claim 9
Dependent Claim
50 words
The die cast machine according to claim 6 wherein said control valve means further comprises a safety check valve connected between said fore chamber and said first transfer valve and said pilot check valve, and means for closing said safety check valve when the pressure of said pressurized liquid decreases.
Claim 10
Dependent Claim
88 words
The die cast machine according to claim 1 which further comprises an additional cylinder connected to the fore end of said injection cylinder to surround a piston rod of said piston to form a space between the inner surface of said additional cylinder and said piston rod, means to supply pressurized liquid into said space, and a sealing member provided about the periphery of said piston, said piston rod and said piston being provided with passages for supplying the pressurized fluid in said space to said sealing member.
References Cited (Backward Citations)
US3891126A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-09 | 1980-11-08 | 1981-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-09 | 1984-11-08 | 1985-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-09 | 1988-11-08 | 1989-05-10 | $7700.00 | Window Closed / Lapsed |