Abstract: A flow rate transducer has a housing in which a cylindrical fluid chamber and a support portion surrounded by an annular guide groove formed coaxial with the fluid chamber are formed. Rotatably carried by the support portion is a vane wheel having plate pieces arranged circumferentially of the vane wheel at regular intervals and extending in the guide groove. A light emitting element and a light receiving element are disposed to face a locus defined by the rotated plate pieces so that, every time the plate pieces pass by the light receiving element, the light receiving element produces an electrical signal to measure the flow rate of a fluid in the fluid chamber. The support portion has vane wheel speed adjusting chambers each having an L-shaped configuration and opening to said guide groove for minimizing the flow rate measurement errors of the flow rate transducer both in the high and low rate regions.

Abstract: In a flow rate transducer of the type arranged to detect the rotational speed of a blade wheel by transmitting a light beam from one side thereof to the other, a printed circuit board for carrying thereon a light-emitting element and a light-receiving element is provided. The light-emitting element and the light-receiving element are received in recessed portions of a casing made of a transparent material, where all parts including the printed circuit board contained in the casing are fixedly supported by a synthetic resin filling. The optical axes of the light-emitting element and the light-receiving element can be readily adjusted to align before assembled in the casing. The size and shape of the recessed portions may be arranged to correspond to the size and shape of the corresponding light-emitting element and the light-receiving element so that optical axes alignment can be automatically performed when fitted therein.

Abstract: A radiator cap composed of a cap body, a compression gasket assembly connected to the cap body and adapted to open and close in accordance with the pressure of the coolant in the radiator, a float engaged with the cap body so as to move up and down in accordance with the level of the coolant. The upper edge of the float is formed so that upon contact with a gasket assembly, a valve is formed with said gasket assembly. A reed switch secured to the cap body is opened or closed in response to movement of the float so that the reed switch actuates suitable warning means when the level of coolant falls over a predetermined line.

Abstract: Liquid level detectors known in the art are, for the most part, designed so that they are mounted in a vertical direction to the liquid level. However, with the recent trend toward using liquid containers of more complicated shapes, there has existed a need for a liquid level detector of a type that can be mounted in a horizontal direction with respect to the liquid level. Moreover, there has existed a need for a liquid level detector of a type which requires as small a mounting opening as possible. In accordance with the present invention, there is provided a liquid level detector in which a permanent magnet is fixedly mounted on the central portion of a float having a long and slender shape, e.g., elliptic or rectangular shape and being enabled to slide along a case containing a reed switch therein and to positively bring the reed switch into operation to detect the liquid level, and which thus meets the above-mentioned requirements.

Abstract: A central warning apparatus for vehicles which comprises a plurality of sensors mounted to the plurality of portions of vehicle to be inspected, discriminator circuits for discriminating an abnormal state of the sensors, display units connected to the discriminator circuits so as to be effected in response to the abnormal state, an OR-gate circuit connected to the output of respective discriminator circuits, and a main warning unit connected to the OR-gate circuit so as to be effected by an output therefrom for warning that there arises an abnormal state at at least one of portions to be inspected.