Abstract: A linear actuator comprising a hollow first cylindrical shaft with helical threads on its exterior surface and helical threads of opposite pitch on its interior surface and a second cylindrical shaft having an exterior surface with helical threads of the same pitch as on the interior surface of the first shaft and a motor for rotating the first shaft and relative to the second shaft end a base member. The second cylindrical shaft is coaxial with and adjacent the first shaft surface and its threads engage the threads of the first interior surface. Helical threads on the base member of the same pitch as the first shaft exterior surface threads are coaxial with and adjacent the first shaft exterior surface and engage the helical threads of the exterior surface of the first cylindrical shaft.

Abstract: A caging system is used in a magnetic platform which is mounted on a pointing system on a spacecraft. The magnetic platform supports a payload, and provides a frictionless support in all conditions. The caging system clamps the payload in a caged condition and provides a frictionless support in an uncaged condition. The caging system includes a plurality of caging actuators. Each caging actuator has an upper support structure which connects to a snubber member, and has a lower support structure which connects to a first ring and to a coaxial second ring for clamping the snubber member. A cylindrical cam member has a plurality of groove surfaces and the first and second rings respectively have a plurality of cam followers. Clockwise rotation of the cam member urges the rings together. Counterclockwise rotation urges the rings apart. A second, auxiliary caging actuator is provided.

Abstract: A controlled capillary ball bearing cage composed of a plurality of layers woven mesh containing warp and woof strands. Selected removal of warp strands forms uniformly spaced cylindrical lubricant reservoirs around the circumference of ball bearing pockets machined into the cage.

Abstract: A full rotational, substantially zero friction electrical conductor assembly conducts relatively high electrical currents between a pair of relatively rotatable members. Electrical conductor modules are axially stacked to provide multiple circuit capabilities wherein each module has a pair of electrical conductive rings affixed to the rotatable members defining an annular radial gap therebetween. A plurality of resilient filamentary conductor loops are disposed between these conductive rings, and the loops contact, roll on, and are captured by the conductive rings thereby providing electrical continuity between the relatively rotatable members. Loop separating spools are interspaced between and in rolling contact with the conductor loops to prevent the loops from touching one another and generating frictional losses. A circular raceway, carried by one of the rotatable members, keeps the spools in rolling alignment with the loops.

Abstract: A full or partial rotational, substantially zero friction electrical conductor assembly conducts the electrical currents of a large number of electrical circuits between a pair of relatively rotatable members in a minimum axial length. A plurality of concentric, annular, radially spaced gaps are formed between corresponding concentric, concave surfaced, electrically conductive rings affixed to the members, such that a large number of circuits may be accommodated in a reduced axial length assembly. Resilient, filamentary conductor loops are disposed between the conductive rings, and the loops contact, roll on, and are captured by the concave surfaces of the conductive rings, thereby providing electrical continuity between the relatively rotatable members. The conductor loops are sealed within individual structural enclosures, thus, providing an environmentally clean and rugged assembly.

Abstract: A tool for use with a full rotational freedom, substantially zero friction electrical contact assembly of the type disclosed in U.S. Pat. No. 4,068,909 comprising a notched rod of a diameter less than the normal concentric gap between the conductor rings, for receiving conductor loops in hanging relation thereon, the rod being mounted in a support base which includes a guide means for radially and axially positioning the rod within a preassembly eccentric gap between the normally concentric conductor rings. Upon closing the eccentric gap to its normal concentric relation, the loops are captured by the conductor rings and the notched rod is withdrawn.

Abstract: A full rotational freedom, substantially zero friction electrical contact assembly for conducting electrical currents between relatively rotatable members of sensitive instruments such as gyroscopic devices and the like and a method of and apparatus for the assembly thereof is disclosed. Each electrical transfer unit of the assembly comprises a pair of coaxial, concentric, coplanar, continuous, concave conductor rings, one mounted on a relatively fixed member and the other mounted on the rotatable member, the relative diameters of the rings providing a substantial annular radial gap therebetween. A resilient, electrically conducting, continuous, filamentary loop is disposed in the radial gap such that its generally flat outside surface contacts and rolls on the concave surfaces of the concentric conductor rings.