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Digital Hydraulic Actuators

IP.com Disclosure Number: IPCOM000094828D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 59K

Publishing Venue

IBM

Related People

Raider, JW: AUTHOR

Abstract

The incremental digital actuator in drawing A uses two bistable valves 1 and 2 for control of output ram 12. Valves 1 and 2 are actuated by solenoids, not shown. Valve 2 is used to control its direction of motion. Valve 1 is used to control its amplitude of motion. With valves 1 and 2 in the up position as shown, the fluid supply pressure is directed through lines 3... 6 to the bottom of volume piston 7 and is thus maintained in the extreme upper position. When valve I is placed in the lower position, the fluid pressure is directed against the top of piston 7 through lines 3, 4, 8 and 9. In turn, piston 7 is moved to the extreme lower position thus displacing a calibrated volume of fluid from volume cylinder 16 and into the right side of actuating cylinder 10 through lines 6 and 11.

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Digital Hydraulic Actuators

The incremental digital actuator in drawing A uses two bistable valves 1 and 2 for control of output ram 12. Valves 1 and 2 are actuated by solenoids, not shown. Valve 2 is used to control its direction of motion. Valve 1 is used to control its amplitude of motion. With valves 1 and 2 in the up position as shown, the fluid supply pressure is directed through lines 3... 6 to the bottom of volume piston 7 and is thus maintained in the extreme upper position. When valve I is placed in the lower position, the fluid pressure is directed against the top of piston 7 through lines 3, 4, 8 and 9. In turn, piston 7 is moved to the extreme lower position thus displacing a calibrated volume of fluid from volume cylinder 16 and into the right side of actuating cylinder 10 through lines 6 and 11. Thus, output ram 12 moves a calibrated distance to the left.

Because of the larger area on the right side of ram piston 12a, the supply pressure fluid, provided by line 13, on the left side of cylinder 10 is forced into supply pressure line 13. Restriction 14 is placed in line 13 to provide damping of ram 12. If valve 1 is next moved upward, the fluid supply pressure through lines
3... 6 causes piston 7 to move upward and displace another calibrated volume of fluid into cylinder 10 through the lines 9 and 11. Successive alternate downward and upward movements of valve 1 cause ram 12 to continue discrete motions to the left.

To achieve motion to the right for ram 12, assuming valve 1 is again in the upper position, valve 2 is placed in the lower position.

The fluid return pressure now propagates to the bottom side of piston 7 via lines 6, 5, 4 and 15, causing piston 7 to be forced and maintained in the lower position. As a result, one calibrated volume of fluid is withdrawn from the right side of cylinder 10 and placed into cylinder 16 again in the upper position, valve 2 is placed in the lower position. The fluid return pressure now propagates to the bottom side of piston 7 via lines 6, 5, 4 and 15, causing piston 7 to be forced and maintained in through lines 11 and
9. Ram 12 is forced to the right by the supply pressure which is maintained, via line 13, on the left side of piston 12a of cylinder
10.

If valve 1 is next moved downward, the fluid return pressure is now directed on the top side of piston 7 through lines 9, 8, 4 and 15. As a result, piston 7 moves upward causing an...