Abstract: A fin control actuator for missiles carried on aircraft has a device which locks the fin shaft against aerodynamic loads and prevents the transmission of these loads through the drive train. The fin shaft lock includes a plunger which has a cam having a locking portion for engaging the output shaft and preventing the output shaft from rotating in one direction when the plunger is in the locking position. The cam also has a camming portion for engaging the output shaft and pushing the plunger to the retracted position when the output shaft rotates in the opposite direction. The plunger is urged into the locking position by a spring and is held in the retracted position by a permanent magnet. The fin lock device is reusable and does not consume any power after it is set.

Abstract: A magnetic brake provides braking or locking capability and is remotely controlled by electric power. The magnetic brake comprises a rotatable shaft and a brake disc mounted on the shaft. A non-rotating core housing assembly located around the shaft includes a permanent magnet and a bipolar solenoid. A magnetic armature adjacent to the core housing assembly is capable of movement toward the core housing assembly and toward and into engagement with a brake disc to prevent rotation of the shaft. A spring urges the armature away from the core housing assembly and into engagement with the brake disc. The brake does not use any electric power to maintain the brake in the set mode with the rotating shaft fully locked, or in the released mode with the rotating shaft fully released. The permanent magnet is of sufficient strength to hold the armature against urging of the spring until an opposite polarity is supplied by the solenoid.

Abstract: A mechanism is disclosed which produces linear motion from a rotating input while preventing the transmission of back forces in either direction. The mechanism includes a housing with an output shaft mounted for rotation within the housing. A rotatable input drive means is mounted coaxial with the shaft. The drive means includes a radially extending impelling portion. The output shaft extends axially on both sides of the impelling portion. A tubular hub is fixedly mounted on the housing and extends around the output shaft on each side of the impelling portion of the drive means. A pair of coil springs are wrapped around the output shaft with one spring on each side of the impelling portion of the drive means. Each spring has a release toe at one end which extends axially to the impelling portion and which is capable of being engaged by the impelling portion upon rotation of the drive means. The other end of each spring engages the shaft, so that the spring rotates with the shaft.