PURPOSE: To make it possible to prevent a vehicle from moving due to insufficient braking force, by detecting the moving speed of a vehicle which initiates to move from its rest condition, and by issuing a discriminating signal when the moving speed is within a predetermined low speed range, for warning the movement of the vehicle.
CONSTITUTION: A vehicle initiates to gradually move on a sloping road surface when the braking force of the vehicle is insufficient upon the vehicle being brought into a stop on a sloping road etc. Pulse signals which are therefore generated by a speed sensor 20 in proportion to a moving speed such as, for example, 5km/hr, are delivered through a wave shaping circuit 30 to a discriminating circuit 40 in which the signals are converted into voltage signals for being compared with a voltage corresponding to a speed of zero and a voltage correpsonding to a speed of 5km/hr. An AND gate 46 issues a discriminating signal between the speeds, for flashing a lamp 61 in combination with pulse signal from an unsatble multivibrator 51. Then, a buzzer 62 is actuated in predetermined intervals by the unstable multivibrator 51 after the elapse of a predetermined time period due to a delay circuit 56. Accordingly, the driver may promptly take necessary operations for surely stopping the vehicle.
YAMADA KOUKICHI
KUROYAMA TOSHINOBU
TOYOTA MOTOR CO LTD