Linear actuator with speed controlling brake

An actuator comprising:

• a recirculating ball screw device including a ballnut journaled for rotation about a first axis, and a lead screw drivingly connected to and carried by said ballnut;
• a force transmitting reciprocating member attached to said lead screw and mounted for reciprocating movement along a path at least partially coincident with said first axis;
• and
• a centrifugally actuated brake operatively connected to said reciprocating member in a manner to be driven by and to limit the speed of said reciprocating movement of said reciprocating member along said path;
• said centrifugally actuated brake including in combination,
• a radially inner driven member mounted for rotation about a second axis and including a radially extendible first frictional surface configured to move radially outward from an initial retracted position incident with a non-rotating condition of the driven member to a maximum extended position in response to centrifugal forces generated as a result of rotation of the driven member, and
• a stationary radially outer member having disposed upon a cylindrical radially inner surface thereof a second frictional surface,
• said second frictional surface being spaced radially outward from said first frictional surface at a distance less than said maximum extended position of the first frictional surface whereat the first frictional surface will be caused to frictionally contact the second frictional surface in response to rotation of said driven member;
• said driven member of said brake including;
• a shaft rotatable about said second axis and having a radially directed hole passing perpendicularly through said shaft;
• a guide pin extending through said hole and from alternate sides of said shaft;
• a pair of circular arch-shaped brake shoes slideably mounted on said guide pin on alternate sides of said shaft, said first frictional surface being provided by a radially outer surface of said brake shoes;
• a retainer attached at each end of said guide pin for retaining said brake shoes thereupon;
• and
• a spring disposed between said retainer and said brake shoe at each end of said guide pin for urging said brake shoes toward said retracted position.

An actuator comprising:

• a force transmitting reciprocating member including a lead screw of a recirculating ball screw device;
• said reciprocating member being mounted for reciprocating movement between a first position and a second position along a path;
• said lead screw of said reciprocating member being drivingly connected to and carried by a ballnut journaled for rotation about a first axis at least partially coincident with said path;
• self contained force producing means operatively connected to said reciprocating member for storing energy when said reciprocating member is disposed between said first and second positions along said path and applying force for urging said reciprocating member toward said second position along said path;
• and
• reset means operably connected to said reciprocating member for returning said reciprocating member to said first position along said path, and for simultaneously resetting the force producing means.

An actuator comprising:

• a recirculating ball screw device including a ballnut journaled for rotation about a first axis, and a lead screw drivingly connected to and carried by said ballnut;
• a force transmitting reciprocating member attached to said lead screw and mounted for reciprocating movement along a path at least partially coincident with said first axis;
• and
• a disengageable locking device for preventing rotation of the ballnut;
• said locking device being capable of selectively preventing rotation of the, ballnut in either direction;
• said locking device further being capable of allowing rotation of the ballnut in one direction while simultaneously preventing rotation of the ballnut in an opposite direction;
• said locking device including in combination:
• a ratchet wheel having radially spaced ratchet teeth attached to said ballnut for rotation about said first axis in a plane of rotation perpendicular to said first axis;
• a pawl having a first end pivotably mounted for angular rotation between a first and a second angular position within said plane of rotation about a pivot point located radially outward of said ratchet wheel along a line extending radially from said first axis in the plane of rotation,
• said pawl having a second end configured to engage said ratchet teeth of said ratchet wheel when said pawl is disposed in either said first or second angular positions;
• and
• a locking pin engageable to prevent said pawl from rotating angularly in the plane of rotation within a circular sector centered at the pivot point and angularly bounded by the first and second angular positions;
• said ratchet teeth, pawl, and locking pin being configured and operatively interconnected such that when said locking pin is engaged with said pawl in said first angular position, said pawl engages said ratchet teeth in a manner which allows said ballnut to rotate freely in one direction of rotation and prevents said ballnut from rotating in an opposite direction of rotation;
• said ratchet teeth, pawl, and locking pin also being configured and operatively interconnected such that when said locking pin is engaged with said pawl in said second angular position, said pawl engages said ratchet teeth in a manner which allows said ballnut to rotate freely in said opposite direction of rotation and prevents said ballnut from rotating in said one direction of rotation;
• said ratchet teeth, pawl, and locking pin also further configured and operatively interconnected such that when said locking pin is disengaged, said pawl may be angularly rotated by said ratchet teeth from one of said first or second angular positions to the other of said first or second angular positions.

In an aircraft having a deployable ram air turbine attached thereto in a manner allowing the ram air turbine to move between a stowed position and a deployed position whereat the ram air turbine extends into the surrounding airstream,

• an ejection jack attached between said aircraft and ram air turbine for moving the ram air turbine between the stowed and deployed positions,
• the ejection jack including a recirculating ball screw device having a ballnut journaled for rotation about a first axis, and a lead screw drivingly connected to and carried by said ballnut;
• said lead screw being free to move axially along said first axis, and including a force transmitting reciprocating member attached to said lead screw with said force transmitting reciprocating member being mounted for reciprocating movement along a path at least partially coincident with said first axis;
• said ballnut being free to rotate about the axis in response to axial movement of the lead screw incident with reciprocating movement of the force transmitting reciprocating member along the path;
• with said reciprocating movement of said reciprocating force transmitting member of said ejection jack causing movement of the ram air turbine between the stowed and deployed positions.

In an aircraft having a deployable ram air turbine attached thereto in a manner allowing the ram air turbine to move between a stowed position and a deployed position whereat the ram air turbine extends into the surrounding airstream,

• an ejection jack attached between said aircraft and said ram air turbine for moving the ram air turbine between the stowed and deployed positions, said ejection jack including:
• integral drive means including a recirculating ballscrew device having a force transmitting reciprocating member for moving the ram air turbine from the stowed position to the deployed position;
• and
• internally contained, resettable, stored energy force producing means operatively connected to said force transmitting reciprocating member to provide motive force thereto;
• said integral drive means including reset means for returning said ram air turbine to said stowed position and for simultaneously resetting said force producing means.

In an aircraft having a deployable ram air turbine attached thereto in a manner allowing the ram air turbine to move between a stowed position and a deployed position whereat the ram air turbine extends into the surrounding airstream,

• an ejection jack attached between said aircraft and said ram air turbine for moving the ram air turbine between the stowed and deployed positions, said ejection jack including:
• integral drive means including a recirculating ballscrew device having a force transmitting reciprocating member for moving the ram air turbine from the stowed position to the deployed position;
• and
• disengagable locking means for restraining the ram air turbine at a point along a path extending between and including the stowed and deployed positions.