Ultrasonic rangefinder

• US 4,796,726 A
• Filed: 11/06/1987
• Issued: 01/10/1989
• Est. Priority Date: 05/29/1984
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Obayashi, Hiroaki, Kobayashi, Hiroshi
• Primary Examiner(s): STEINBERGER, BRIAN
• Application Number:
  US07/117,807
• Time in Patent Office: 431 Days
• Field of Search: 181/108, 181/109, 181/110, 181/123, 181/124, 181/139, 181/144, 181/146, 181/147, 181/151, 181/192, 181/DIG. 1, 181/208, 367/99, 367/106, 367/130, 367/140, 367/162, 367/165, 367/173, 367/176, 367/188, 367/910
• US Class Current: 181/123
• CPC Class Codes: G01S 7/521 Constructional features
• CPC Class Codes: G01S 7/527 Extracting wanted echo signals Doppler systems G01S15/50
• CPC Class Codes: G10K 11/002 Devices for damping, suppressing, obstructing or conducting sound in acoustic devices G10K1/06 - G10K1/10 take precedence; for electro-mechanical transducers for communication H04R3/002
• CPC Class Codes: G10K 11/004 Mounting transducers, e.g. provided with mechanical moving or orienting device mountings specially adapted to a particular sound-producing device, see the preceding groups G10K1/00 - G10K9/00, e.g. G10K1/26, G10K1/28, G10K9/22; arrangements of sonic watch equipment on submarines B63G8/39; buoys B63B22/00
• CPC Class Codes: G11B 20/1876 Interpolating methods

Abstract

An ultrasonic rangefinder capable of detecting a distance between a vehicle and an object with high accuracy is shown. The measure of microphones for transmitting and receiving ultrasonic waves is chosen so that detour waves are restricted.

Claims

1. An ultrasonic rangefinder for measuring the distance between the rangefinder and an object, said rangefinder comprising:

means for transmitting an ultrasonic wave toward the object and having a transmitting surface;

means for receiving an ultrasonic wave reflected from the object and having a receiving surface;

a casing having two cavities for housing said transmitting and receiving means, respectively, and provided with a signal-processing unit for processing signals supplied from the transmitting and receiving means to measure the distance between the rangefinder and the object, said signal-processing unit being disposed in a concave portion formed in a connecting section between the transmitting and receiving means; and

a foaming insulator having an independent cell structure and covering the interior walls of at least one of said cavities whereby ultrasonic waves from the transmitting means are prevented from directly propagating to the receiving means through the interior of the casing.