System for warning the approach of an emergency vehicle

• US 4,238,778 A
• Filed: 09/12/1977
• Issued: 12/09/1980
• Est. Priority Date: 09/12/1977
• Status: Expired due to Term

• Current Assignee: Kinya Ohsumi
• Original Assignee: Kinya Ohsumi
• Inventors: Ohsumi, Kinya
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Groody, James J.
• Application Number:
  US05/832,286
• Time in Patent Office: 1,184 Days
• Field of Search: 340/32, 340/34, 340/33, 340/694, 340/696, 343/225, 343/226, 343/227, 343/228, 235/92 EV, 325/363, 325/364, 325/55, 325/64, 325/466, 325/117, 325/54, 325/400, 325/398, 325/319, 325/406, 325/312, 455/352, 455/227, 455/68, 455/99, 455/57, 455/232, 455/238, 455/345
• US Class Current: 340/903
• CPC Class Codes: G08G 1/0965 responding to signals from another vehicle, e.g. emergency vehicle

Abstract

An electronic transmitter-receiver system for warning a motor vehicle driver of the approach of an emergency motor vehicle such as an ambulance is disclosed. A transmitter equipped emergency motor vehicle transmits an omnidirectional, short range, radio frequency warning signal. A warning signal receiver associated with a motor vehicle proximate to the approaching emergency motor vehicle emits an audible warning within the passenger compartment of the motor vehicle in response to the radio frequency warning signal. The audible warning is heard by the driver of the motor vehicle thus alerting him to the impending traffic hazards associated with an approaching emergency motor vehicle. The intensity of the audible warning increases as the distance between the emergency motor vehicle and the motor vehicle to be warned decreases. The warning signal receiver includes means for disabling selected sound producing devices within the passenger compartment of the motor vehicle, such as a radio or a ventilation fan, in response to the warning signal.

Claims

1. A system for warning the approach of an emergency motor vehicle comprising:

a warning signal transmitter constructed and arranged for mounting on an emergency motor vehicle, said transmitter including means for generating and transmitting a radio frequency warning signal; and

a warning signal receiver constructed and arranged for mounting on a motor vehicle to be warned of the approach of the emergency motor vehicle, said receiver including means for detecting said radio frequency warning signal, means for comparing the intensity of said detected signal to a threshold signal of predetermined intensity, said means for comparing providing an ON switching signal only when the intensity of said detected signal exceeds the predetermined intensity of said threshold signal, means for generating an audible frequency tone similar to a siren sound of the emergency motor vehicle, means for emitting the audible frequency tone within the passenger compartment of said vehicle to be warned only when said ON switching signal is provided, means for varying the intensity of said audible frequency tone in proportion to the intensity of said detected signal, and means for disabling selected sound producing sources within said passenger compartment when said ON switching signal is provided.