Electromechanical control actuator system

Claim 2

A motion-transmitting apparatus comprising: a fixed support, a primary drive means adapted for rotary movement and engaged by a first set of threads with said fixed support, said primary drive means adapted for axial movement relative to said fixed support in response to rotation, a secondary drive means adapted for rotary movement, a coupling means engaged by a second set of threads with said primary drive means and by a third set of threads with said secondary drive means, said first and second sets of threads having the same sense but different pitches, a coupling stop means adapted to prevent rotation of said coupling means, an actuator engaged by a fourth set of threads with said secondary drive means, said third and fourth sets of threads having the same sense but different pitches, and an actuator stop means adapted to prevent rotation of said actuator.

Claim 3

A motion-transmitting apparatus according to claim 1 wherein the difference in pitch between said first and second sets of threads is different from the difference in pitch between said third and fourth sets of threads.

Claim 4

A motion-transmitting apparatus according to claim 2 wherein the pitches and senses of said first, second, third and fourth sets of threads are adapted to produce relative axial movement between said coupling means and said actuator in response to rotation of said primary and secondary drive means.

Claim 5

A motion-transmitting apparatus according to claim 3 wherein the pitches and senses of said first, second, third and fourth sets of threads are such that a given amount of rotation of said primary and secondary drive means in the same direction produces axial movement of a given magnitude between said actuator and said fixed support, and said given amount of rotation of said primary and secondary drive means in opposite directions produces between said actuator and said fixed support a greater magnitude of relative axial movement.

Claim 6

A motion-transmitting apparatus according to claim 4 including a common drive mechanism adapted to rotate said primary drive means and said secondary drive means at the same angular velocity.

Claim 7

A motion-transmitting apparatus according to claim 5 including individual drive means adapted to permit independent rotation of said primary and secondary drive means.

Claim 8

A motion-transmitting apparatus according to claim 6 including biasing means adapted to maintain pressure between said first, second, third and fourth sets of threads.

Claim 9

A motion-transmitting apparatus comprising: a fixed internally threaded support, a hollow primary drive cylinder adapted for rotary movement and having external threads that engage the internal threads on said fixed support and form therewith a first set of threads, said primary drive means adapted for axial movement relative to said fixed support in response to rotation, a hollow secondary drive cylinder adapted for rotary movement, a hollow coupling cylinder having external threads that engage internal threads on said primary drive cylinder and form therewith a second set of threads, said first and second sets of threads having the same sense but different pitches, said coupling cylinder also having internal threads that engage external threads on said secondary drive cylinder and form therewith a third set of threads, a coupling stop means adapted to prevent rotation of said cylindrical coupling means, an actuator having external threads that engage internal threads on said secondary drive cylinder and form therewith a fourth set of threads, said third and fourth sets of threads having the same sense but different pitches, the difference in pitch between said first and second sets of threads being different than the difference in pitch between said third and fourth sets of threads, and an actuator stop means adapted to prevent rotation of said actuator.

Claim 10

A motion-transmitting apparatus comprising: a fixed internally threaded support, a hollow primary drive cylinder adapted for rotary movement and having external threads that engage the internal threads on said fixed support and form therewith a first set of threads, said primary drive means adapted for axial movement relative to said fixed support in response to rotation, a hollow secondary drive cylinder adapted for rotary movement, a hollow coupling cylinder having external threads that engage internal threads on said primary drive cylinder and form therewith a second set of threads, said first and second sets of threads having the same sense but different pitches, said coupling cylinder also having internal threads that engage external threads on said secondary drive cylinder and form therewith a third set of threads, a coupling stop means adapted to prevent rotation of said cylindrical coupling means, an actuator having external threads that engage internal threads on said secondary drive cylinder and form therewith a fourth set of threads, said third and fourth sets of threads having the same sense but different pitches, the difference in pitch between said first and second sets of threads being different than the difference in pitch between said third and fourth sets of threads, and an actuator stop means adapted to prevent rotation of said actuator.

Claim 11

A motion-transmitting apparatus according to claim 8 wherein the pitches and senses of said first, second, third and fourth sets of threads are such that a given amount of rotation of said primary and secondary drive means in the same direcTion produces axial movement of a given magnitude between said actuator and said fixed support, and said given amount of rotation of said primary and secondary drive means in opposite directions produces between said actuator and said fixed support a greater magnitude of relative axial movement.

Claim 12

A motion-transmitting apparatus according to claim 9 including a common drive mechanism adapted to rotate said primary drive means and said secondary drive means at the same angular velocity.

Claim 13

A motion-transmitting apparatus according to claim 10 including individual drive means adapted to permit independent rotation of said primary and secondary drive means.

Claim 14

A motion-transmitting apparatus according to claim 11 including biasing means adapted to maintain pressure between said first, second, third and fourth sets of threads.

Claim 15

A motion-transmitting apparatus according to claim 12 wherein said coupling and actuator stops comprise key means engaging said fixed support.

Claim 16

A motion-transmitting apparatus according to claim 13 wherein the difference in pitch between said first and second sets of threads is substantially equal to the difference in pitch between said third and fourth sets of threads.