Digitally positioned actuator

Claim 2

Actuator apparatus comprising: a housing having a compartment located therein; digital pulse responsive positioning means; control means selectively applying each successive digital pulse to said positioning means to cause incremental rotation in either of two directions of said positioning means; fluid operated axially movable actuator means Having an actuator piston with a chamber defined therein, said actuator piston being mounted in said compartment; means for supplying pressurized fluid to said actuator means; means for moving said actuator piston in one axial direction; a pair of valves disposed in said actuator piston chamber of said actuator means; rigid motion transmission means directly connected to said positioning means and directly operatively adapted to independently position said pair of valves; and said rigid motion transmission means responsive to bidirectional motion of said positioning means independently displacing each of said valves to control a flow of operating fluid to said actuator piston to thereby position said actuator piston in the other axial direction and establish an intermediate dead band wherein neither of said pair of valves is open.

Claim 3

The apparatus of claim 1 wherein: said actuator piston is axially disposed in said compartment and defines first and second chambers; said pair of valves is disposed in said actuator piston chamber such that opening one of said valves admits pressurized fluid to said first chamber, and opening the other of said valves exhausts pressurized fluid from said first chamber; and wherein there is further provided, follower means comprising said actuator piston, said pair of valves and said rigid motion transmission means constructed and arranged to produce a finite axial movement of said actuator piston responsive each displacement of said motion transmission means.

Claim 4

Actuator apparatus in accordance with claim 2 in which said positioning means includes a stepping motor and a rack and pinion gear assembly.

Claim 5

Actuator apparatus in accordance with claim 3 in which said control means includes: means for generating a feedback signal commensurate with the actual position of the stepping motor output shaft; means summing said actual position feedback signal and an input signal to generate a resultant control input signal; and means phasing said digital pulses to said positioning means responsive to said resultant control input signal.

Claim 6

Actuator apparatus in accordance with claim 2 in which said positioning means includes a stepping motor and a ball and screw assembly.

Claim 7

Actuator apparatus in accordance with claim 5 in which said control means includes: means for generating a feedback signal commensurate with the actual position of the stepping motor output shaft; means summing said actual position feedback signal and an input signal to generate a resultant control input signal; and means phasing said digital pulses responsive to said resultant control input signal.

Claim 8

A power actuator device having an output member comprising: a source of pressurized fluid; positioning means having a discrete rotational movement in response to each received electrical pulse; control means selectively positioning each successive electrical pulse in response to a control input signal to rotate said positioning means in either of two directions; actuator means including an actuator piston fixedly secured to said output member; an axially movable rigid member connected to said positioning means and operably attached to flow control means, including a plurality of valve means, positioned in said actuator means to thereby direct said flow of pressurized fluid to said actuator piston and to effect an adjustable dead band in said flow control means whereby said plurality of valve means are simultaneously closed; and followup means including said actuator piston acting in concert with said rigid member to control the flow of pressurized fluid to said actuator means independent of an acceleration force environment and thus position said followup means such that each incremental rotary position of said positioning means produces a corresponding incremental linear position of said output means.

Claim 9

A power actuator device having an output member comprising: a source of pressurized fluid; positioning means having a discrete rotational movement in response to each received electrical pulse; control means selectively positioning each successive electrical pulse in response to a control input signal to rotate said positioning means in either of two directions; actuator means including an actuator piston fixedly secured to said output member; an axially movable rigid member connected to said positioning means and operably attached to flow control means, including a plurality of valve means, positioned in said actuator means to thereby direct said flow of pressurized fluid to said actuator piston and to effect an adjustable dead band in said flow control means whereby said plurality of valve means are simultaneously closed; and followup means including said actuator piston acting in concert with said rigid member to control the flow of pressurized fluid to said actuator means independent of an acceleration force environment and thus position said followup means such that each incremental rotary position of said positioning means produces a corresponding incremental linear position of said output means.

Claim 10

A power actuator device in accordance with claim 7 in which said Positioning means includes a stepping motor and a rack and pinion gear assembly.

Claim 11

Actuator apparatus in accordance with claim 8 in which said control means includes: means for generating a feedback signal commensurate with the actual position of the stepping motor output shaft; means summing said actual position feedback signal and an input signal to generate a resultant control input signal; and means phasing said digital pulses responsive to said resultant control input signal.

Claim 12

A power actuator device in accordance with claim 7 in which said positioning means includes a stepping motor and a ball and screw assembly.

Claim 13

Actuator apparatus in accordance with claim 10 in which said control means includes: means for generating a feedback signal commensurate with the actual position of the stepping motor output shaft; means summing said actual position feedback signal and an input signal to generate a resultant control input signal; and means phasing said digital pulses responsive to said resultant control input signal.

Claim 14

Actuator apparatus operated in a substantial acceleration or vibratory induced field comprising in combination: a linearly movable output member; a source of pressurized fluid; digital pulse actuated bidirectional rotary positioning means; control means selectively directionally applying each successive digital pulse to said rotary positioning means to cause incremental rotation in either of two directions of said positioning means; actuator means including a pressurized fluid operated actuator piston having a chamber located therein, said chamber including means controlling the flow of said pressurized fluid to said actuator piston; said actuator piston fixedly connected to said output member, a rigid linear motion transmission member connected to said positioning means and said flow control means such that for each incremental bidirectional rotary movement of said positioning means a corresponding incremental linear movement of said motion transmission member is produced; and said flow control means having separate inlet and exhaust valves so constructed and arranged that said valves are independently linearly positioned by said member to control the flow of said pressurized fluid to said actuator means such that, unaffected by vibratory or acceleration generated forces, a finite position of said linearly movable output member is registered for each finite rotary position of said positioning means, and a dead band is established wherein both said inlet and said exhaust valves are closed.

Claim 15

Actuator apparatus operated in a substantial acceleration or vibratory induced field comprising in combination: a linearly movable output member; a source of pressurized fluid; digital pulse actuated bidirectional rotary positioning means; control means selectively directionally applying each successive digital pulse to said rotary positioning means to cause incremental rotation in either of two directions of said positioning means; actuator means including a pressurized fluid operated actuator piston having a chamber located therein, said chamber including means controlling the flow of said pressurized fluid to said actuator piston; said actuator piston fixedly connected to said output member, a rigid linear motion transmission member connected to said positioning means and said flow control means such that for each incremental bidirectional rotary movement of said positioning means a corresponding incremental linear movement of said motion transmission member is produced; and said flow control means having separate inlet and exhaust valves so constructed and arranged that said valves are independently linearly positioned by said member to control the flow of said pressurized fluid to said actuator means such that, unaffected by vibratory or acceleration generated forces, a finite position of said linearly movable output member is registered for each finite rotary position of said positioning means, and a dead band is established wherein both said inlet and said exhaust valves are closed.

Claim 16

A power actuator in accordance with claim 12 in which said flow control means comprises: a first fluid supply passage located in said actuator piston, said inlet valve positioned intermediate said first passage such that pressurized fluid is delivered to a first side of said actuator piston responsive to the opening of said inlet valve; and a second fluid passage located in said actuator piston with said exhaust valve positioned therein such that pressurized fluid is exhausted from said first side of said actuator piston responsive to the opening of said exhaust valve.