Abstract: A frame structure has a structural unit containing six elongated posts, each post having first and second ends, the structural unit capable of having at least an unfolded state where the six posts are substantially contained in one plane and a folded state where the six posts extend substantially parallel to each other. The frame structure has post-midpoint joints formed in each of the posts for supporting the posts of the structural unit foldably at approximate midpoints of the posts; a central joint for supporting the posts of the structural unit at the first ends of each of the posts rotatably in a plane perpendicular to the plane of the unfolded state. The six posts of the structural unit are positioned in the unfolded state such that the posts extend radially from the central joint within substantially one plane, so that a line connecting the second ends of the six posts of the structural unit forms substantially an equilateral hexagon.

Abstract: An unfoldable connected structure has a structural unit movable in a folded and an unfolded state. The structural unit includes five arm units, and each of the arm units include an inner arm member having first and second ends, an outer arm member having first and second ends, an elbow joint mechanism movably connecting the first end of the inner arm member to the first end of the outer arm member, a shoulder joint mechanism movably connected to the second end of the inner arm member, and a wrist joint mechanism movably connected to the second end of the outer arm member; and means for connecting the arm units radially through their respective shoulder joint mechanism to form a frame of a pentagonal pyramid configuration when the structural unit is in an unfolded state. The unfoldable connected structure forms no void at its outer surface when it is in an unfolded state, has improved structural strength, and allows smooth folding and unfolding action.

Abstract: A guide for as transmission device such as a chain or belt, is injection molded using a sandwich-molding process. The sandwhich-molded guide comprises a slide rail on which a chain or belt slides, and a rail supporting member intergrally provided along with the slide rail. The slide rail is composed of a material the principle component of which is first polymeric material having wear resistance and heat resistance, and the rail supporting member is composed of a material the principle component of which is a second polymeric material having higher strength than the material having the first polymeric material as its principle component. The slide rail and the rail supporting member are intimately joined to each other by injection molding using the sandwhich molding process.

Abstract: A frame structure has a structural unit containing six elongated posts, each post having first and second ends, the structural unit capable of having at least an unfolded state where the six posts are substantially contained in one plane and a folded state where the six posts extend substantially parallel to each other. The frame structure has post-midpoint joints formed in each of the posts for supporting the posts of the structural unit foldably at approximate midpoints of the posts; a central joint for supporting the posts of the structural unit at the first ends of each of the posts rotatably in a plane perpendicular to the plane of the unfolded state. The six posts of the structural unit are positioned in the unfolded state such that the posts extend radially from the central joint within substantially one plane, so that a line connecting the second ends of the six posts of the structural unit forms substantially an equilateral hexagon.

Abstract: An unfoldable connected structure has a structural unit movable in a folded and an unfolded state. The structural unit includes five arm units, and each of the arm units include an inner arm member having first and second ends, an outer arm member having first and second ends, an elbow joint mechanism movably connecting the first end of the inner arm member to the first end of the outer arm member, a shoulder joint mechanism movably connected to the second end of the inner arm member, and a wrist joint mechanism movably connected to the second end of the outer arm member; and means for connecting the arm units radially through their respective shoulder joint mechanism to form a frame of a pentagonal pyramid configuration when the structural unit is in an unfolded state. The unfoldable connected structure forms no void at its outer surface when it is in an unfolded state, has improved structural strength, and allows smooth folding and unfolding action.

Abstract: A guide for a transmission device such as a chain or belt, is injection molded using a sandwich-molding process. The process avoids the need for a complex mold and complex manufacturing steps. The guide exhibits enhanced mechanical strength and excellent sliding contact properties and wear resistance in a compatible manner, and is also light in weight and has excellent durability. The sandwich-molded guide comprises a slide rail on which a chain or belt slides, and a rail supporting member integrally provided along with the slide rail. The slide rail is composed of a material the principal component of which is a first polymeric material having wear resistance and heat resistance, and the rail supporting member is composed of a material the principal component of which is a second polymeric material having higher strength than the material having the first polymeric material as its principal component.

Abstract: A system for spotting moving objects based on a plurality of artificial satellites including: a step of taking images at the same point in time by using imaging devices respectively mounted on at least two units of artificial satellites located separately from one another of which the positions can be defined at every moment in time; a step of discriminating a large number of stars at infinity and a small number of moving objects located near the earth through a synthetic processing by superimposing upon one another at least two images of spots obtained from the image taking at the respective satellites; and a step of specifying the positions of the discriminated moving objects from data of images forming positions of the moving objects on the basis of the large number of stars at infinity.

Abstract: A time-synchronous communication system comprises: fixed stations having distance measuring/time reference synchronization and maintaining unit, receiving/processing unit, transmitting/processing unit, and communication data processing management unit; mobile stations having distance measuring/time reference synchronization and maintaining unit, transmitting/processing unit, receiving/processing unit, and communication data processing management unit; and relay stations having distance measuring radio wave transmitting/processing unit, time reference synchronization and maintaining unit, and radio wave relay unit for relaying transmission radio waves from the fixed stations and the mobile station.

Abstract: A satellite-based position-determining system comprises at least two satellites deployed in geosynchronous orbit and equipped with a receiver, transmitter and clock and a user's equipment of unknown position equipped with a clock and a receiver and transmitter for communications with said satellites. At least one satellite and the user's equipment emit range-finding signals based on their own clocks, and each of them receives the other's range-finding signal and measures the time period from the emission of its own range-finding signal to the reception of the other's range-finding signal. Time errors of both clocks are calculated from the above time periods in order to synchronize both the clocks and the position of the user's equipment is determined.