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US 4,637,272 AGranted
Ballscrew actuator
AssigneeSundstrand Corporation
InventorsDuane R. Teske, Henry E. Senasack, Jr., Mark Wilkins
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AssigneeSundstrand Corporation
InventorsDuane R. Teske, Henry E. Senasack, Jr., Mark Wilkins
Estimating the term…
There are many requirements for an actuator where safety considerations dictate several independent means of actuation. This invention pertains to an actuator utilizing a single ballscrew with drive units associated therewith to provide a level of redundancy which permits full performance with any one credible failure and emergency performance with any two credible failures and, thus, the actuator is dual failure tolerant with full performance after any two credible failures. The ballscrew actuator has a pair of rotatable ballnuts associated with a ballscrew and carried by separate housings movable toward and away from each other. The ballscrew is twice the length of the desired actuating movement, with one-half of the length of the ballscrew being stored in each housing. Primary and backup drive units each having a drive motor are carried by one housing and each have a worm gear set and a selectively engageable clutch for selective driving of the first ballnut. A second housing mounts an emergency drive unit having a drive motor which, through a worm gear set, drives a second ballnut. Normal operation of the actuator is derived from operation of either the primary or backup drive units and, when there is a failure in the operation of both of these drive units, the emergency drive unit can be operated to assure movement of the actuator for safe positioning of a device moved by the actuator, such as the payload and support structure of a space vehicle.
An actuator utilizing a single linear ballscrew and which is dual failure tolerant comprising, a pair of ballnuts on said ballscrew which may translate relative to each other lengthwise of said linear ballscrew, first and second housings for connection one with each of a pair of members that are to be moved relative to each other and each having one of the ballnuts rotatable therein, a pair of independently operable drive units on the first housing and each having a drive motor, means for drivingly connecting one or the other of said drive motors to a first of said pair of ballnuts rotatable in the first housing including clutch means having disengaged positions and engaged positions for connecting one or the other of the drive motors to said first ballnut, and a third drive unit on the second housing including a drive motor, and means drivingly connecting the third drive unit motor to the second of said pair of ballnuts.
A ballscrew actuator utilizing a single ballscrew and which is dual failure tolerant comprising, a pair of housings connectable one to each of a pair of members that are to be moved relative to each other, a pair of ballnuts rotatably associated with the ballscrew and rotatably mounted one in each housing, said ballscrew having a length approximately equal to twice the distance of movement between said members and being stored approximately one-half in each housing when said members are in proximate relation to each other, a first of said pair of housings rotatably mounting a first of said pair of ballnuts, a primary drive unit and a backup drive unit mounted on said first housing for selectively rotating said first ballnut, each of said drive units including a drive motor, a driven worm gear, a shiftable clutch geared to the worm gear, and means for engaging and disengaging the clutch with the first ballnut, a second of said housings rotatably mounting a second of the ballnuts, and an emergency drive unit mounted on said second housing including a drive motor and a driven worm gear geared to the second ballnut.
A ballscrew actuator utilizing a single ballscrew and which is dual failure tolerant comprising, a pair of housings, a pair of ballnuts rotatably associated with the ballscrew and rotatably mounted one in each housing, said ballscrew having a length stored in each housing when said housings are in proximate relation to each other, a first of said pair of housings rotatably mounting a first of said pair of ballnuts, a primary drive unit and a backup drive unit mounted on said first housing for selectively rotating said first ballnut, each of said drive units including a drive motor, a shiftable clutch, and means for engaging and disengaging the clutch with the first ballnut, a second of said housings rotatably mounting a second of the ballnuts, and a third drive unit mounted on said second housing including a drive motor geared to the second ballnut.
An actuator which is dual failure tolerant comprising, a ballscrew, a pair of ballnuts on said ballscrew, first and second housings each rotatably mounting one of the ballnuts, a pair of independently operable drive units on the first housing and each having a drive motor, means for drivingly connecting one or the other of said drive motors to a first of said pair of ballnuts associated with the first housing including a pair of clutches having disengaged positions and engaged positions for selectively connecting one of the drive motors to said first ballnut, and a third drive unit on the second housing including a drive motor, and means drivingly connecting the third drive unit motor to the second of said pair of ballnuts.
Dependencies are inferred from the claim text.