Ultrasonic transmitting and receiving device

Claim 1

An ultrasonic transmitting and receiving device comprising the combination of a semi-cylindrical outer case having at least one opening in the front wall thereof, said opening extending around a major portion of the semi-cylindrical outer case so as to form an opening of substantially 180* , a semi-cylindrical screen mounted over said opening, an inner case housed in said outer case and pivoted thereto so as to be rotatable around a vertical axis within said outer case for controlling the direction of transmission of ultrasonic waves, the inner case being rotatable independently of the outer case so that the outer case remains in a fixed position regardless of the position of the inner case, a pair of chambers formed by said inner case and each having an opening in the front wall of said inner case, said pair of chambers being disposed above and below one another, at least one shielding plate disposed on the front of said inner case between said openings of said pair of chambers and extending horizontally to block direct transmission of ultrasonic waves between said pair of chambers, a pair of ultrasonic oscillating elements each of which is mounted in the upper region of one of said chambers and directed downwardly, one of said elements being an ultrasonic transmitter and the other being an ultrasonic receiver, a pair of reflectors each of which is mounted in the lower region of one of said chambers spaced from the corresponding oscillating element and inclined by about 45* with respect to said vertical axis of said chambers, said reflectors facing the respective openings of the respective chambers, and a pair of conical horns each of which is mounted between one of said ultrasonic oscillating elements and the corresponding reflector and expanding in diameter in the direction toward the reflector.