Abstract: In a Vuilleumier heat pump, hot and cold displacers are supported by coil springs in respective buffer chambers. Further, there are respectively provided forced vibration systems of the hot and cold displacers using, as exciting force, force applied to respective displacer rods due to a difference between a pressure fluctuation of a working gas in an inner working space and a pressure in the buffer chambers. A linear motor is also provided to drive the hot displacer so as to reciprocate. It is thereby possible to provide the Vuilleumier heat pump in which a mechanism for driving the hot and cold displacers can have a small-sized and simplified structure, and no restriction is imposed on an arrangement of hot and cold cylinders.

Abstract: A card carrier in use with an optical data record/reproduction system for reading data from and writing data to a card, including a press contact slide member (26, 27) which prevents a table for carrying the card from being tilted and deviated from a predetermined traveling direction, and a table drive member which prevents the transfer of a vibration to the table. With this arrangement, data is exactly written into and read out from the card.

Abstract: This device is an arrangement for detecting a signal for effecting a focus control of an optical head with respect to an optical information recording medium by making use of a reflected light beam from the optical information recording medium. On an optical path for a reflected light beam reflected from the recording surface of the optical recording medium, a photodetector is provided. This photodetector is composed of a plurality of elements arranged symmetrically in the transverse cross section of the light beam. Thus, an output of the outside element and an output of the inside element of the plural elements arranged in the transverse cross section of the light beam are used to detect a focus error, thus to utilize the signal detected for the focus control.

Abstract: This device is an arrangement for detecting a signal for effecting a focus control of an optical head with respect to an optical information recording medium by making use of a reflected light beam from the optical information recording medium. On an optical path for a reflected light beam reflected from the recording surface of the optical recording medium, a photodetector is provided. This photodetector is composed of a plurality of elements arranged symmetrically in the transverse cross section of the light beam. Thus, an output of the outside element and an output of the inside element of the plural elements arranged in the transverse cross section of the light beam are used to detect a focus error, thus to utilize the signal detected for the focus control.

Abstract: A read/write apparatus for information memory card which is improved in durability of the card and the apparatus itself, and in reliability of information processing.When a card is completely inserted, a connector is swung toward the card until contactors of the connector are pressed on terminals of a memory built in the card, so that the memory and an information processing unit are connected via the connector to facilitate flawless information exchange therebetween, whereby data processing is ensured.Upon completion of information processing, the connector is detached from the card so that the movement of the card causes no wear or damage on the contactors nor the card itself.

Abstract: In an optical memory card reading device of the type comprising a card feeding means for feeding a card inserted into an insertion inlet into the device, an optical reader means for illuminating the memory surface of the optical memory card thus fed in and receiving the reflected light rays from the memory surface and a circuit for converting the information read out by the optical reader means into an electric signal which in turn is analyzed to detect the contents in the memory, an optical memory card reading device characterized by the provision of a card cleaning means which is disposed adjacent to the card insertion inlet for cleaning the memory of the inserted card.

Abstract: An improved Stirling engine has a piston and a crosshead slidably disposed inside a cylinder and secured to one another by a piston rod so as to reciprocate as a single body with a space formed between the crosshead and the piston. An oil-deflecting guard for deflecting oil which is scattered by the movement of the crosshead is disposed between the crosshead and the piston and is supported so as to move with the crosshead. A first oil-absorbing member for absorbing oil which enters the space above the oil-deflecting guard is disposed on the oil-deflecting guard on the piston side thereof. A second oil-absorbing member is disposed between the first oil-absorbing member and the piston with a space therebetween. The space between the crosshead and the piston can be connected with the inside of a crankcase by oil drainage holes.

Abstract: A non-linear resistive element which is formed by sintering a body of zinc oxide which includes cobalt, strontium, barium, yttrium and magnesium.