Variable pitch linear actuator with variable thrust

Claim 2

In a linear actuator having a housing with a longitudinally extending cylindrical bore and a plurality of wheels in said housing, a shaft, said shaft being rotatably and slidably mounted in said bore, means for urging said wheels each being disposed adjacent said bore, means for urging said wheels against the surface of said shaft for controlling movement of said housing with respect to said shaft as said shaft is rotated with respect to said housing, said means for urging including means for simultaneously varying the pressure applied to each of said wheels, said pressure-varying means being responsive to an externally controlled device so that the thrust of said linear actuator may be varied from an external source as said shaft rotates with respect to said housing.

Claim 3

The invention of claim 1 wherein said housing further includes radially extending bores for each wheel, said wheels being rotatable within said bores about the axis of said bore.

Claim 4

The invention of claim 1 wherein said means for varying the pressure applied to said wheels includes a diaphragm for each wheel, said diaphragms being connected to a source of fluid pressure, said diaphragms urging said wheels against said shaft in accordance with the pressure applied against said diaphragms.

Claim 5

The invention of claim 1 wherein said linear actuator further includes a longitudinally movable plate, said plate being connected to each of said wheels, said wheels being rotated about an axis perpendicular to said shaft in accordance with the movement of said plate.

Claim 6

In a linear actuator having a housing with a longitudinally extending cylindrical bore and a plurality of wheels mounted in said housing, a shaft, said shaft being rotatably and slidable mounted in said bore, said wheels each being disposed adjacent said bore, a longitudinally movable plate, said plate being connected to each of said wheels via an elongated bar and an arcuate link, said wheels each having a lever member for varying the pitch of said wheels, said lever members each being connected to said arcuate link so that said wheels are rotated about an axis perpendicular to said shaft in accordance with the movement of said plate, means for urging said wheels against the surface of said shaft for controlling movement of said housing with respect to said shaft as said shaft is rotated with respect to said housing, said means for urging including a member for varying the pressure applied to said wheels, said member being responsive to a remotely controlled device so that the thrust of said linear actuator may be varied from a remote source.

Claim 7

In a linear actuator having a housing with a longitudinally extending cylindrical bore and a plurality of wheels mounted in said housing, a shaft, said shaft being rotatably and slidable mounted in said bore, said wheels each being disposed adjacent said bore, a longitudinally movable plate, said plate being connected to each of said wheels via an elongated bar and an arcuate link, said wheels each having a lever member for varying the pitch of said wheels, said lever members each being connected to said arcuate link so that said wheels are rotated about an axis perpendicular to said shaft in accordance with the movement of said plate, means for urging said wheels against the surface of said shaft for controlling movement of said housing with respect to said shaft as said shaft is rotated with respect to said housing, said means for urging including a member for varying the pressure applied to said wheels, said member being responsive to a remotely controlled device so that the thrust of said linear actuator may be varied from a remote source.

Claim 8

The invention of claim 5 wherein said housing includes a pair of end walls, said walls having a plurality of openings, said elongated bare each being slidably mounted in said openings to move with said plate.

Claim 9

In a linear actuator having a housing with a longitudinally extending cylindrical bore and a plurality of wheels mounted in said housing, a shaft, said shaft being rotatably and slidably mounted in said bore, said wheels each being disposed adjacent said bore, a longitudinally movable plate, said plate being connected to each of said wheels, said wheels being rotated about an axis perpendicular to said shaft in accordance with the movement of said plate, means for urging said wheels against the surface of said shaft for controlling movement of said housing with respect to said shaft is rotated with respect to said housing, said means for urging including a member for varying the pressure applied to said wheels, said member being responsive to a remotely controlled device so that the thrust of said linear actuator may be varied from a remote source, said housing further including a pair of axially extending projections, said projections adapted to be rotatably mounted in a supporting saddle so that said housing may be rotated while said shaft remains stationary to provide linear motion to said housing along said shaft.

Claim 10

In a linear actuator having a housing with a longitudinally extending cylindrical bore and a plurality of wheels mounted in said housing, a shaft, said shaft being rotatably and slidably mounted in said bore, said wheels each being disposed adjacent said bore, a longitudinally movable plate, said plate being connected to each of said wheels, said wheels being rotated about an axis perpendicular to said shaft in accordance with the movement of said plate, means for urging said wheels against the surface of said shaft for controlling movement of said housing with respect to said shaft is rotated with respect to said housing, said means for urging including a member for varying the pressure applied to said wheels, said member being responsive to a remotely controlled device so that the thrust of said linear actuator may be varied from a remote source, said housing further including a pair of axially extending projections, said projections adapted to be rotatably mounted in a supporting saddle so that said housing may be rotated while said shaft remains stationary to provide linear motion to said housing along said shaft.

Claim 11

The invention of claim 7 wherein said saddle includes a pivotable lever member and a pair of linking bars, each of said linking bars having a pivotable forked member secured thereto, said for members being slidably mounted about the periphery of said plate so that rotation of said lever member causes movement of said plate for varying the pitch of said Wheels.

Claim 12

In a linear actuator having a housing with a longitudinally extending cylindrical bore and a plurality of wheels mounted in said housing, a shaft, said shaft being rotatably and slidably mounted in said bore, said wheels each being disposed adjacent said bore, said wheels each being pivotable about an axis perpendicular to the axis of said shaft, means for urging said wheels against the surface of said shaft for controlling movement of said housing with respect to said shaft as said shaft is rotated with respect to said housing, a longitudinally movable plate, said plate being connected to each of said wheels so that movement of said plate longitudinally changes the pitch of said wheels with respect to said shaft.

Claim 13

In a linear actuator having a housing with a longitudinally extending cylindrical bore and a plurality of wheels mounted in said housing, a shaft, said shaft being rotatably and slidably mounted in said bore, said wheels each being disposed adjacent said bore, said wheels each being pivotable about an axis perpendicular to the axis of said shaft, means for urging said wheels against the surface of said shaft for controlling movement of said housing with respect to said shaft as said shaft is rotated with respect to said housing, a longitudinally movable plate, said plate being connected to each of said wheels so that movement of said plate longitudinally changes the pitch of said wheels with respect to said shaft.

Claim 14

The invention of claim 9 wherein said housing further includes a longitudinally extending projection which includes said longitudinal bore, said plate having a central opening through which said projection extends, and said wheels each having lever members, said lever member of each wheel being connected to said plate by a pivotable linking member and an elongated bar.