Failure detection circuit for anti-skid braking system

• US 5,176,429 A
• Filed: 11/29/1990
• Issued: 01/05/1993
• Est. Priority Date: 12/01/1989
• Status: Expired due to Fees

• Current Assignee: Nissinbo Industries Incorporated
• Original Assignee: Nissinbo Industries Incorporated
• Inventors: Hamada, Toshihiro, Junichi, Kaneko
• Primary Examiner(s): Graham, Matthew C.
• Application Number:
  US07/621,459
• Time in Patent Office: 768 Days
• Field of Search: 303/92, 303/100, 364/426.03
• US Class Current: 303/122.05
• CPC Class Codes: B60T 2270/406 Test-mode; Self-diagnosis
• CPC Class Codes: B60T 2270/414 Power supply failure
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: Y10S 303/09 Plural processors

Abstract

An improved failure detection circuit for anti-skid braking systems is disclosed. The failure detection circuit sends electrical test pulses to the individual valves which control the flow of pressurized brake fluid to the individual brakes and uses a feedback signal from these valves to determine a failure in any of these circuits. The failure detection circuit also includes a voltage monitoring circuit which monitors the voltage which is supplied to the anti-skid braking controller while applying an electrical load to the main power circuit for the controller such as by testing a plurality of valves at once. If the voltage drops below a minimum acceptable level, it indicates an actual or incipient failure of the main power supply circuit. This indication can be used to trigger a warning or to shut down the anti-skid braking system as can a detection of a failure in an individual circuit.

Claims

1. A failure detection circuit for the main electrical power circuit in an anti-skid braking system comprising:

(a) an electrical power source;

(b) a plurality of solenoid valves, each solenoid having a power lead and a ground lead;

(c) a common terminal which connects the power lead of each of the plurality of solenoid valves with one another;

(d) a logic circuit for controlling current which flows from the common terminal to ground through each of the solenoid valves;

(e) a main electrical power circuit connected between the electrical power source and the common terminal for feeding electrical power to the solenoid valves;

(f) a voltage monitoring circuit for detecting drops in voltage below a given threshold voltage value in the common terminal;

(g) a serial circuit of a lamp, and a diode connected between the electrical power source and the common terminal, the diode preventing current from flowing from the common terminal to the lamp; and

(h) a switching circuit connected between the common terminal side of the lamp and ground;

wherein current flows from the electrical power source to ground through the lamp at once when the switching circuit shuts and open by using a pulse signal thereby reducing the voltage in the common terminal and permitting the voltage monitoring circuit to detect a drop in voltage below the given threshold voltage value when the main electrical power circuit fails.