US3835647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple speed hydraulic drive circuit
Assignee: SPX Technologies Inc
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Filing: 1972-01-27
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Granted: 1974-09-17
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Expires: 1992-01-27
Abstract
Abstract THE DISCLOSURE CONCERNS A HYDRAULIC POWER CIRCUIT PARTICULARLY SUITED FOR USE IN DRIVING THE ELEVATOR OF AN EARTH-MOVING SCRAPER, AND WHICH AFFORDS THREE DRIVING SPEEDS IN THE FORWARD DIRECTION AND ONE DRIVING SPEED IN REVERSE. THE CIRCUIT PREFERABLY EMPLOYS TWO FIXED DISPLACEMENT PUMPS OF DIFFERENT CAPACITIES, AND A PAIR OF PILOT OPERATED CONTROL VALVES WHICH SELECTIVELY CAUSE THE OUTPUT OF EITHER OR BOTH PUMPS TO BE DELIVERED TO THE DRIVE MOTOR. THE CONTROL VALVES ARE SO ARRANGED THAT THEY MAY BE INCORPORATED IN A SINGLE, CONVENTIONAL VALVE BODY, AND THAT NEITHER HAS TO BE SIZED TO HANDLE THE COMBINED OUTPUTS OF BOTH PUMPS.
Inventors
- 👤 T Huffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:37
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/4148; F15; F15B; F15B11/00; F15B11/02; F15B11/04; F15B11/042; F15B11/0426; F15B13/00; F15B13/02; F15B13/04; F15B13/042; F15B13/0422; F16H61/44; F16H61/444; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/20576; F15B2211/20584; F15B2211/255; F15B2211/30; F15B2211/305; F15B2211/30505; F15B2211/30525; F15B2211/31; F15B2211/3105; F15B2211/3111; F15B2211/32; F15B2211/329; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50518; F15B2211/50527; F15B2211/50536; F15B2211/515; F15B2211/5151; F15B2211/5153; F15B2211/5154; F15B2211/70; F15B2211/705; F15B2211/7058
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |