Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
258 words
A valve operator comprising: a. a housing; b. an externally threaded valve stem supported in said housing; c. a nut on said valve stem supported in said housing; d. first reversible drive means; e. a first gear train connecting said first drive means to said nut for driving said nut rotationally thereby to move said stem axially in one direction or the other according to the direction of rotation of said nut; f. a pair of roll-ramp units mounted in said housing in opposing relation to each other, one unit on each side of said nut; g. each roll-ramp unit comprising a stationary cam surface, a movable cam surface, and roller means providing roller contact between said stationary and movable cam surfaces; h. thrust bearing means on each side of said nut between each roll-ramp unit and said nut; i. second reversible drive means; j. a second gear train connecting said second drive means to said movable cam of each roll-ramp unit by way of a gear sector for concurrently driving said movable cams through but a fraction of one revolution, thereby to drive said roll-ramp units concurrently in opposite manner for exerting thrust against said nut in the axial dirction of said stem, thereby to move said stem axially in one direction or another according to the direction of rotation of said second drive means, the total extent of said movement of said stem by said second drive means being within a distance not exceeding the sum of the rise of said stationary and movable cam surfaces.
Claim 2
Dependent Claim
258 words
A valve operator comprising: a. a housing; b. an externally threaded valve stem supported in said housing; c. a nut on said valve stem supported in said housing; d. first reversible drive means; e. a first gear train connecting said first drive means to said nut for driving said nut rotationally thereby to move said stem axially in one direction or the other according to the direction of rotation of said nut; f. a pair of roll-ramp units mounted in said housing in opposing relation to each other, one unit on each side of said nut; g. each roll-ramp unit comprising a stationary cam surface, a movable cam surface, and roller means providing roller contact between said stationary and movable cam surfaces; h. thrust bearing means on each side of said nut between each roll-ramp unit and said nut; i. second reversible drive means; j. a second gear train connecting said second drive means to said movable cam of each roll-ramp unit by way of a gear sector for concurrently driving said movable cams through but a fraction of one revolution, thereby to drive said roll-ramp units concurrently in opposite manner for exerting thrust against said nut in the axial dirction of said stem, thereby to move said stem axially in one direction or another according to the direction of rotation of said second drive means, the total extent of said movement of said stem by said second drive means being within a distance not exceeding the sum of the rise of said stationary and movable cam surfaces.
Claim 3
Dependent Claim
85 words
A valve operator according to claim 1 characterized in that: a. first control means, including counter means, are provided operatively associated with said first drive means for controlling said first drive means to drive said stem axially from fully open position to an almost-closed position; b. second control means, including torque sensing means, are provided operatively associated with said second drive means for controlling said second drive means for driving said pair of roll-ramp units for moving said stem axially between almost-closed and fully-closed positions.
Claim 4
Dependent Claim
45 words
A valve operator according to claim 2 characterized in that: a. said stationary cam surface is annular; b. said movable cam surface is annular; c. said thrust bearing means are mounted between said movable cam surface and said nut, on each side of said nut.
Claim 5
Dependent Claim
70 words
A valve operator according to claim 3 characterized in that: a. each of said movable annular cam surfaces is integrally connected to a gear sector; b. said gear sector is driven by said second gear train for moving said annular cam surface through a fraction of 360*; c. said fraction of 360* being less than twice the fraction of 360* represented by one rising incline of said annular cam surface.
Claim 6
Dependent Claim
22 words
A valve operator according to claim 4 characterized in that said first and second drive means each includes a worm and gear.
Claim 7
Dependent Claim
89 words
A valve operator according to claim 5 characterized in that: a. said second drive means drive the movable cam surfaces of both roll-ramp units in the same direction at the same time, and b. said pair of opposing roll-ramp units, one on each side of said nut, are so opposingly related that when said movable cam surfaces are driven in the same direction at the same time, said rollers of one unit climb up the cam inclines while the rollers of the other unit roll down the cam inclines.
Claim 8
Dependent Claim
25 words
A valve operator according to claim 6 characterized in that said cam surfaces are so contoured that the angle of incline decreases near the crest.
Claim 9
Dependent Claim
103 words
A valve operator according to claim 6 characterized in that said cam surfaces are so contoured that the angle of incline decreases near the crest. a. said second drive means drive the movable cam surfaces of both roll-ramp units in the same direction at the same time, and said pair of opposing roll-ramp units, one on each side of said nut, are so opposingly related that when said movable cam surfaces are driven in the same direction at the same time, said rollers of one unit climb up the cam inclines while the rollers of the other unit roll down the cam inclines.