Control circuit for vehicle leveling system

Claim 1

A control circuit for a vehicle leveling system to restore a vehicle height to be within a reference vehicle height range by operating either a first drive means to raise a vehicle body or a second drive means to lower the vehicle body when said vehicle height is out of said reference vehicle height range, comprising: a first detecting means for generating a directional signal of vehicle height change in the form of either a HIGH signal or a LOW signal; a second detecting means for generating a command signal of vehicle height adjustment in the form of either an OFF signal or an ON signal; main circuit means for selecting for operation either said first drive means to raise said vehicle height or said second drive means to lower said vehicle height in response to said directional signal, and for determining whether or not said drive means is to be actuated; holding circuit means, connected between said second detecting means and said main circuit means, for increasing the duration of said OFF signal for a predetermined length of time when said OFF signal appears instantaneously, and for transmitting said OFF signal with said duration to said main circuit means; and said holding circuit means comprising a monostable multivibrator connected so as to receive said command signal from said second detecting means, and an OR gate connected so as to receive said command signal from said second detecting means and an output from said monostable multivibrator.