US3255778A — Servo valve mechanism

Claim 1

Independent Claim 252 words

A CHATTERLESS SERVO VALVE ASSEMBLY FOR CONTROLLING THE DIRECTION AND AMOUNT OF MOVEMENT OF A FLUID MOTOR WITH HIGH PRECISION, SAID SERVO VALVE ASSEMBLY COMPRISING A CYLINDRICAL HOUSING RECIPROCABLY SUPPORTING A SPOOL VALVE THEREION HAVING A PAIR OF LANDS SPACED TO EITHER SIDE OF A PRESSURIZED FLUID SUPPLY GROOVE, A PAIR OF ANNULAR GROOVES IN SAID HUSING HAVING A WIDTH AND SO DISPOSED RELATIVE TO SAID LANDS AS TO PROVIDE EXACTLY EQUAL CONDITIONS OF FLOW AND FLUID PRESSURE BETWEEN SAIF FLUID SUPPLY GROOVE IN SAID SPOOL AND SAID PAIR OF GROOVES IN THE PRECISE NEUTRAL POSIITON ONLY OF SAID SPOOL AND UNEQUAL FLOW BUT CONTINUING BALANCED PRESSURE CONDITIONS IN ALL OTHER POSITIONS TO EITHER SIDE OF SAID NEUTRAL POSITION, SAID SPOOL HAVING AN EXHAUST GROOVE ON THE REMOTE SIDES OF EACH OF SAID LANDS, THE REMOTELY SPACED RIM EDGE OF EACH OF SAID LANDS BEING GROUND OFF AT A PLURALITY OF EQUALLY SPACED ELONGATED AREAS EXTENDING CIRCUMFERENTIALLY ALONG SAID RIM EDGES, EACH OF SAID AREAS BEING IDENTICAL WITH ONE ANOTHER AND LYING AT AN ANGLE TO THE SPOOL AXIS AND BEING WIDEST AT ITS MIDPORTION AND TAPERING SHARPLY IN OPPOSITE DIRECTIONS INTO MERGER WITH SAID RIM EDGES WITH THE SURFACE OF EACH OF SAID ELONGATED AREAS LYING IN A CONICAL SURFACE HAVING ITS AXIS PARALLEL TO THE AXIS OF SAID SPOOL AND ITS CENTER RADIALLY OFFSET BY AN IDENTICAL DISTANCE FROM SAID SPOOL AXIS AND FURTHER CHARACTERIZED IN THAT THE CIRCUMFERENTIAL LENGTH OF SAID AREAS IS SEVERAL TIMES THE TRANSVERSE WIDTH THEREOF.

Claim 2

Dependent Claim 252 words

A CHATTERLESS SERVO VALVE ASSEMBLY FOR CONTROLLING THE DIRECTION AND AMOUNT OF MOVEMENT OF A FLUID MOTOR WITH HIGH PRECISION, SAID SERVO VALVE ASSEMBLY COMPRISING A CYLINDRICAL HOUSING RECIPROCABLY SUPPORTING A SPOOL VALVE THEREION HAVING A PAIR OF LANDS SPACED TO EITHER SIDE OF A PRESSURIZED FLUID SUPPLY GROOVE, A PAIR OF ANNULAR GROOVES IN SAID HUSING HAVING A WIDTH AND SO DISPOSED RELATIVE TO SAID LANDS AS TO PROVIDE EXACTLY EQUAL CONDITIONS OF FLOW AND FLUID PRESSURE BETWEEN SAIF FLUID SUPPLY GROOVE IN SAID SPOOL AND SAID PAIR OF GROOVES IN THE PRECISE NEUTRAL POSIITON ONLY OF SAID SPOOL AND UNEQUAL FLOW BUT CONTINUING BALANCED PRESSURE CONDITIONS IN ALL OTHER POSITIONS TO EITHER SIDE OF SAID NEUTRAL POSITION, SAID SPOOL HAVING AN EXHAUST GROOVE ON THE REMOTE SIDES OF EACH OF SAID LANDS, THE REMOTELY SPACED RIM EDGE OF EACH OF SAID LANDS BEING GROUND OFF AT A PLURALITY OF EQUALLY SPACED ELONGATED AREAS EXTENDING CIRCUMFERENTIALLY ALONG SAID RIM EDGES, EACH OF SAID AREAS BEING IDENTICAL WITH ONE ANOTHER AND LYING AT AN ANGLE TO THE SPOOL AXIS AND BEING WIDEST AT ITS MIDPORTION AND TAPERING SHARPLY IN OPPOSITE DIRECTIONS INTO MERGER WITH SAID RIM EDGES WITH THE SURFACE OF EACH OF SAID ELONGATED AREAS LYING IN A CONICAL SURFACE HAVING ITS AXIS PARALLEL TO THE AXIS OF SAID SPOOL AND ITS CENTER RADIALLY OFFSET BY AN IDENTICAL DISTANCE FROM SAID SPOOL AXIS AND FURTHER CHARACTERIZED IN THAT THE CIRCUMFERENTIAL LENGTH OF SAID AREAS IS SEVERAL TIMES THE TRANSVERSE WIDTH THEREOF.

Claim 3

Dependent Claim 169 words

AN ARTICLE OF MANUFACTURE COMPRISING A CIRCULAR ONE-PIECE VALVE MEMBER HAVING AN ANNULAR GROOVE ENCIRCLING ITS MIDPORTIONS AND SPACED BETWEEN A PAIR OF IDENTICAL LANDS LYING IN A COMMON SURFACE OF REVOLUTION, THE REMOTELY SPACED RIM EDGES OF SAID LANDS BEING IDENTICALLY RELIEVED AT A PLURALITY OF AREAS EXTENDING CIRCUMFERENTIALLY THEREALONG, SAID RELIVED AREAS TAPERING SHARPLY AT THEIR OPPOSITE ENDS TO POINTS OF MERGER WITH THE NONRELIEVED PORTIONS OF SAID REMOTE RIM EDGES AND HAVING A LENGTH CIRCUMFERENTIALLY OF SAID VALVE MEMBER SEVERAL TIMES GREATER THAN THE WIDTH THEREOF AND SAID RELIEVED AREAS LYING IN IDENTICAL SURFACES OF REVOLUTION HAVING CENTERS IDENTICALLY OFFSET FROM THE AXIS OF SAID VALVE MEMBER, AND SAID IDENTICAL SURFACES OF REVOLUTION BEING SPACED EAUIDISTANTLY FROM ONE ANOTHER CIRCUMFERENTIALLY OF EACH OF SAID REMOTELY SPACED RIM EDGES WHEREBY PRESSURIZED FLUID FLOWING ACROSS SAID IDENTICAL SURFACES OF REVOLUTION IS EFFECTIVE TO MAINTAIN SAID VALVE MEMBER BALANCED AND CENTERED COAXIALLY OF AN ENCLOSING HOUSING IN WHICH SAID VALVE IS ADAPTED TO BE MOUNTED IN CLOSE-FITTING SLIDING RELATION.

Claim 4

Dependent Claim 169 words

AN ARTICLE OF MANUFACTURE COMPRISING A CIRCULAR ONE-PIECE VALVE MEMBER HAVING AN ANNULAR GROOVE ENCIRCLING ITS MIDPORTIONS AND SPACED BETWEEN A PAIR OF IDENTICAL LANDS LYING IN A COMMON SURFACE OF REVOLUTION, THE REMOTELY SPACED RIM EDGES OF SAID LANDS BEING IDENTICALLY RELIEVED AT A PLURALITY OF AREAS EXTENDING CIRCUMFERENTIALLY THEREALONG, SAID RELIVED AREAS TAPERING SHARPLY AT THEIR OPPOSITE ENDS TO POINTS OF MERGER WITH THE NONRELIEVED PORTIONS OF SAID REMOTE RIM EDGES AND HAVING A LENGTH CIRCUMFERENTIALLY OF SAID VALVE MEMBER SEVERAL TIMES GREATER THAN THE WIDTH THEREOF AND SAID RELIEVED AREAS LYING IN IDENTICAL SURFACES OF REVOLUTION HAVING CENTERS IDENTICALLY OFFSET FROM THE AXIS OF SAID VALVE MEMBER, AND SAID IDENTICAL SURFACES OF REVOLUTION BEING SPACED EAUIDISTANTLY FROM ONE ANOTHER CIRCUMFERENTIALLY OF EACH OF SAID REMOTELY SPACED RIM EDGES WHEREBY PRESSURIZED FLUID FLOWING ACROSS SAID IDENTICAL SURFACES OF REVOLUTION IS EFFECTIVE TO MAINTAIN SAID VALVE MEMBER BALANCED AND CENTERED COAXIALLY OF AN ENCLOSING HOUSING IN WHICH SAID VALVE IS ADAPTED TO BE MOUNTED IN CLOSE-FITTING SLIDING RELATION.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1969-06-13	1969-12-13	1970-06-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1973-06-13	1973-12-13	1974-06-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1977-06-13	1977-12-13	1978-06-14	$7700.00	Window Closed / Lapsed

Servo valve mechanism

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