Abstract: An automatic door closing hinge is configured in such a manner that first balls (43) are engaged with a first cam groove (35) formed on an outer peripheral surface of an operating rod in a cylinder (2) at opposed positions so as to have a substantially V-shape at opposed positions thereof, the first balls (43) are engaged with a compression ring (4) urged downward by a compression coil spring (5), the movement of the first balls (43) with respect to the first cam groove (35) is in conjunction with the movement of the compression ring, second balls (65) are engaged with a second cam groove (36) formed under the first cam groove (35) and having substantially the same shape as the first cam groove (35), the second balls (65) are engaged with the piston (6), the movement of the second balls (65) with respect to the second cam groove (36) is in conjunction with the movement of the piston, and air on the lower side of the piston (6) in the cylinder is gradually flowed out according to the movement of the piston.

Abstract: An automatic door closing hinge configured to absorb a shock by an air damper which can be installed on a double swing door opening inward and outward and a double swing door structure provided with the automatic door closing hinge are provided.

Abstract: A plane transformer has both a primary plane coil and secondary plane coils fitted in a fitting groove formed on a substrate composed of a magnetic substance. At least either of the primary plane coil and the secondary plane coils is separated into two, so that an output voltage is variably controlled by changing the numbers of turns of the primary and secondary plane coils. The plane transformer can be small in size and thickness, reduces generated heat, and hardly emits electromagnetic noises.