Abstract: A detection signal of a frequency corresponding to a rotational frequency is applied to a frequency-voltage converter and its converted voltage signal is provided to a sine-cosine current generator, from which sine-wave and cosine-wave currents having sine and cosine values corresponding to the voltage value of the voltage signal are supplied to a cross-coil rotary magnet type indicator for providing an indication of the rotational frequency by a pointer. When the power source is cut off, interruption of the power source voltage supply to the frequency-voltage converter and the sine-cosine current generator is delayed by delay means and, in the delay time, the input to the sine-cosine current generator is reduced, returning the pointer to the zero point. The indicator further includes a zero-resetting magnet which interacts with the rotary magnet to force the pointer to move to said zero point.

Abstract: A signal generator which generates one pulse for each predetermined distance of travel of a vehicle. A rotary member is driven by the rotation of a wheel of the vehicle, and the rotary member has arranged thereon reflecting and non-reflecting portions alternately with each other about a rotary shaft of the rotary member. A pair of optical transmission lines are disposed to confront at one end the surface of the rotary member on which the reflecting and non-reflecting portions are arranged. Light is emitted from a light emitting element to the other end of one of the optical transmission line, and light reflected by the rotary member is incident to the other optical transmission line and received by a photo detector provided at the other end of the optical transmission line. In dependence on whether the reflecting or non-reflecting portion of the rotary member lies opposite to the optical transmission lines, the output from the photo detector varies to provide a travel-distance signal.

Abstract: A luminant pointer for use in a meter is disclosed, which comprises a finger portion having a trapezoidal sectional shape with the transverse width of its upper face being selected to be longer than that of its lower face, and a layer of color paint provided on the lower face of the finger portion. The entire upper face of the finger portion of the pointer having such a construction can thus glow with the color of the paint in spite of the fact that the color paint layer is provided merely on the lower face having a considerably smaller area than that of the upper face of the finger portion of the pointer. Therefore, the amount of the paint required for the luminant indication purpose is decreased to reduce the rate of absorption of light by the paint, thereby obviating the tendency of sharp reductions in the intensity of light advancing from the radially inner end toward the radially outer end of the finger portion of the pointer on the meter dial.

Abstract: A rotation displaying device for displaying the rotating speed of an engine, especially, that of an agricultural machine such as a combine harvester, in colors classified by the low speed, standard speed and high speed. The device comprises a rotary shaft rotating at a speed proportional to the rotating speed of the engine, and a color pattern plate urged in one direction by the centrifugal force produced by the rotation of the rotary shaft. The color pattern plate is provided on its surface with a pattern of three different colors, and the color pattern changing with the successive displacement of the color pattern plate is viewed through a single central displaying opening of a display plate to display the low speed, standard speed and high speed of the engine.

Abstract: The present invention relates to a selective absorption surface of a solar collector in which a coating layer consisting of the predetermined composition of metal oxide is tightly adhered to a substrate having the mirror-like surface in the predetermined thickness.The composition of metal oxide consists of those comprising 0.001 - 0.15 wt % of C, 0.005 - 3.00 wt % of Si, 0.005-10.00 wt % of Mn, 11.00 - 30.00 wt % of Cr, 0.005 - 22.00 wt % of Ni, optionally, 0.75 - 5.00 wt % of Mo and the balance being Fe or those comprising instead of Cr, 0.001 - 5.0 wt % of at least one of metals selected from the group of N, Cu, Al, V, Y, Ti, Nb, Ta, U, Th, W, Zr, and Hf, the atom ratio of Metal/Carbon + additional element being more than 5.0. An acidic oxidation method and an alkaline oxidation method are applied to manufacture oxide of the metal compositions.It has been observed that the superior selective absorption surface showing high energy absorption factor at a wave length of 0.3 - 2.5 .mu.

Abstract: A solar water heater of natural circulation type provided with a reflector for improving the heat collecting efficiency of a heat collector especially in the winter season. The reflector is disposed to satisfy two essential conditions. The first essential condition provides that solar radiation reflected from the reflecting surface of the reflector be substantially entirely directed toward the heat collecting surface of the heat collector at the southing time of the winter solstice, while the second essential condition provides that solar radiation incident upon the heat collecting surface of the heat collector be not excessively interrupted by the reflector at the southing time of the summer solstice.

Abstract: An absorption refrigerator of natural circulation type comprising a first generator connected to the lower end of a gas-liquid lift and a second generator connected to the upper end of the gas-liquid lift. A solution of an absorbing medium, which may be an aqueous solution of a salt of lithium, is heated in the first generator to be lifted through the gas-liquid lift into the second generator, and the lithium salt solution is then concentrated to a predetermined concentration in the second generator.

Abstract: The present invention relates to providing incombustible polyolefin molding compositions having good properties such as electric insulating property, flexibility, heat resisting property, antismoking property and mechanical property. The said superior properties are brought about by adding zirconium oxide to the polyolefin composition.In particular, the superior antismoking property is brought about by the synergistic effect of adding zirconium oxide and aluminum oxide or hydroxide to the polyolefin composition. The polyolefin molding composition of the present invention is suitable for the coating composition of electric wire.

Abstract: An absorption refrigerator of natural circulation type employing water as a refrigerant and lithium salt as an absorbing medium, in which a U-tube is disposed in a conduit portion between a condenser and an evaporator and is connected at one end thereof to a separator in addition to the condenser and at the other end thereof to a refrigerant reservoir. A cooling conduit extends into this refrigerant reservoir to maintain substantially constant the internal pressure of the reservoir so that the amount of the refrigerant stored in the reservoir can be controlled depending on the pressure difference between the separator side of the U-tube and the reservoir side of the U-tube. Therefore, the concentration of the lithium salt solution circulating through the refrigeration system can be controlled depending on the temperature of a heating medium supplied to a generator.