Patent US3956973A successfully refreshed from Google Patents.
US3956973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Die casting machine with piston positioning control
Assignee: BASIC ALUMINUM CASTINGS Co
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Filing: 1974-01-02
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Granted: 1976-05-18
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Expires: 1994-01-02
Abstract
Abstract A die casting machine has a piston rod connected to its main ram for positioning the ram as the piston rod extends and retracts from a cylinder. A control system is provided which directly senses the position, velocity and acceleration of the piston rod. A smooth continguous outer surface is formed on the piston rod. Magnetic and non-magnetic materials spaced alternately axially along the rod provide a series of magnetic discontinuity fields along the piston rod. Transducers are provided to sense the magnetic discontinuities as the piston rod moves to provide signals indicative of the position, velocity and acceleration of the piston rod. An electrohydraulic servo valve is electrically connected to the transducers and to a control console for moving the piston rod and for recording its position, velocity, and acceleration.
Inventors
- 👤 Leonard J. Pomplas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:58
CPC Classifications
F; F15; F15B; F15B15/00; F15B15/20; F15B15/28; F15B15/2815; F15B15/2846; B; B22; B22D; B22D17/00; B22D17/20; B22D17/32; B29; B29C; B29C45/00; B29C45/17; B29C45/76; B30; B30B; B30B15/00; B30B15/16; B30B15/18; F01; F01B; F01B31/00; F01B31/12; F15B15/2861; G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/20; G01D5/2006; G01D5/2013; G01P; G01P15/00; G01P15/16; G01P3/00; G01P3/42; G01P3/50
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
183 words
A cylinder and reciprocating piston combination, comprising: a. a cylinder body defining a chamber and having an open end; b. a piston movable in said chamber in response to a supply of pressurized fluid to said chamber; c. a piston rod connected to said piston for movement therewith relative to said body and extending through said open end; d. said piston rod being formed from a first magnetic material having a peripheral surface including a plurality of axially spaced groove portions said peripheral surface and said groove portions being covered by a second non-magnetic material which provides a smooth outer wear surface for said piston rod; e. packing means carried by said body and forming a seal circumferential of said wear surface to inhibit the escape of pressurized fluid through said open end; and f. transducer means positioned near said wear surface, said first and second materials cooperating to define a magnetic discontinuity means for cooperating with said transducer means to produce electrical pulse signals for indicating the passage past said transducer means of one of the groove portions in said peripheral surface.
Claim 2
Dependent Claim
183 words
A cylinder and reciprocating piston combination, comprising: a. a cylinder body defining a chamber and having an open end; b. a piston movable in said chamber in response to a supply of pressurized fluid to said chamber; c. a piston rod connected to said piston for movement therewith relative to said body and extending through said open end; d. said piston rod being formed from a first magnetic material having a peripheral surface including a plurality of axially spaced groove portions said peripheral surface and said groove portions being covered by a second non-magnetic material which provides a smooth outer wear surface for said piston rod; e. packing means carried by said body and forming a seal circumferential of said wear surface to inhibit the escape of pressurized fluid through said open end; and f. transducer means positioned near said wear surface, said first and second materials cooperating to define a magnetic discontinuity means for cooperating with said transducer means to produce electrical pulse signals for indicating the passage past said transducer means of one of the groove portions in said peripheral surface.
Claim 3
Dependent Claim
17 words
The apparatus of claim 1 wherein said second material fills the groove portions in said peripheral surface.
Claim 4
Dependent Claim
22 words
The apparatus of claim 1 wherein said first material is a ferrous metal and said second material is a substantially non-ferrous metal.
Claim 5
Dependent Claim
13 words
The apparatus of claim 3 wherein said second material is a chrome coating.
Claim 6
Dependent Claim
11 words
The apparatus of claim 1 wherein threads form said groove portions.
Claim 7
Dependent Claim
17 words
The apparatus of claim 1 wherein said second material extends at least partially into the groove portions.
Claim 8
Dependent Claim
46 words
The apparatus of claim 1 wherein said transducer means includes at least two transducer units mounted at axially spaced positions along the path of movement of said piston rod to provide successive variations in electrical signals when said piston rod moves relative to said transducer units.
Claim 9
Dependent Claim
209 words
A cylinder and reciprocating piston combination, comprising: a. a cylinder body defining a chamber and having an open end; b. a piston movable in said chamber in response to a supply of pressurized fluid to said chamber; c. a piston rod connected to said piston for movement therewith relative to said body and extending through said open end; d. said piston rod having a substantially cylindrical core formed from a ferrous metal having a circumferentially grooved peripheral surface, said peripheral surface being covered by a substantially non-ferrous metal coating which extends at least part way into the grooves of said peripheral surface and which extends across peripheral core portions between such grooves to define a smooth, substantially cylindrical outer wear surface extending coaxially of said core; e. packing means carried by said body and forming a seal circumferential of said wear surface to inhibit the escape of pressurized fluid through said open end; and f. transducer means positioned near said wear surface, said ferrous metal core and said non-ferrous metal coating cooperating to define a magnetic discontinuity means for cooperating with said transducer means for providing a variation in an electrical signal indicative of the passage past said transducer means of one of the grooves in said peripheral surface.
Claim 10
Dependent Claim
209 words
A cylinder and reciprocating piston combination, comprising: a. a cylinder body defining a chamber and having an open end; b. a piston movable in said chamber in response to a supply of pressurized fluid to said chamber; c. a piston rod connected to said piston for movement therewith relative to said body and extending through said open end; d. said piston rod having a substantially cylindrical core formed from a ferrous metal having a circumferentially grooved peripheral surface, said peripheral surface being covered by a substantially non-ferrous metal coating which extends at least part way into the grooves of said peripheral surface and which extends across peripheral core portions between such grooves to define a smooth, substantially cylindrical outer wear surface extending coaxially of said core; e. packing means carried by said body and forming a seal circumferential of said wear surface to inhibit the escape of pressurized fluid through said open end; and f. transducer means positioned near said wear surface, said ferrous metal core and said non-ferrous metal coating cooperating to define a magnetic discontinuity means for cooperating with said transducer means for providing a variation in an electrical signal indicative of the passage past said transducer means of one of the grooves in said peripheral surface.
Claim 11
Dependent Claim
11 words
The apparatus of claim 8 wherein said non-ferrous metal is chrome.
Claim 12
Dependent Claim
12 words
The apparatus of claim 8 wherein threads form said grooved peripheral surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |