Control system for regulating the quantity of pressure medium in a suspension system

• US 3,873,123 A
• Filed: 01/29/1974
• Issued: 03/25/1975
• Est. Priority Date: 01/30/1973
• Status: Expired due to Term

• Current Assignee: Knut Joneleit
• Original Assignee: Knut Joneleit
• Inventors: Joneleit, Knut
• Primary Examiner(s): Goodman, Philip
• Application Number:
  US05/437,611
• Time in Patent Office: 420 Days
• Field of Search: 280/124F,6H 267/65D,64
• US Class Current: 280/6.158
• CPC Class Codes: B60G 17/0152 characterised by the action on a particular type of suspension unit B60G17/01941 takes precedence

Abstract

The distance between the body and a wheel axle of a vehicle is determined by the quantity of pressure medium in the suspension system. A first and second switch each changes from a normally open to a closed position when the body of the vehicle is respectively too high and too low relative to the wheel axle. Closing of either switch initiates the charging of a capacitor in a stabilized timing circuit which includes a transistor having a base connected to the capacitor and an emitter connected to a voltage divider which is connected in parallel with the supply voltage and serves to keep the emitter-base voltage of the transistor independent of temperature and supply voltage variations. When the emitter-base voltage reaches a predetermined voltage, voltage is supplied to one terminal of each of two relay coils, the other terminal of which is connected to ground potential via a corresponding one of the switches when closed. The energized relay then causes energization of either a pump for increasing the pressure medium or a valve for decreasing the pressure medium.

Claims

1. In a suspension system for suspending a first member relative to a second member and wherein the distance between said first and second members varies as a function of the quantity of pressure medium in said suspension system, in combination, signal furnishing means for furnishing a control sIgnal when said distance between said first and second member varies from a predetermined distance by at least a predetermined increment;

supply means for furnishing a supply voltage;

timing circuit means energized by said supply voltage and connected to said signal furnishing means for furnishing a timing signal a predetermined time interval following receipt of said control signal, said predetermined time interval having undesired variations as a function of changes in said supply voltage;

stabilizing circuit means including a voltage divider circuit connected to said timing circuit means for stabilizing said timing circuit means with respect to said variations in said supply voltage;

level varying means for changing the quantity of said pressure medium in said suspension system upon energization; and

output circuit means connected to said timing circuit means, said signal furnishing means and said level varying means for energizing said level varying means in the presence of said control signal and upon receipt of said timing signal.

2. A system as set forth in claim 1, wherein said timing circuit means comprise a transistor having a base connected to said signal furnishing means and an emitter-collector circuit changing from a first to a second state upon receipt of said control signal, and a resistor-capacitor circuit connected to said supply means and said first transistor in such a manner that the voltage across said capacitor varies as a predetermined function of time when said emitter-collector circuit is in said second state;

wherein said voltage divider circuit is connected in parallel with said supply means and has a voltage divider tap; and

wherein said stabilizing circuit means further comprise a transistor having a base connected to said resistor-capacitor circuit, an emitter connected to said voltage divider tap and a collector connected to said output circuit means, said transistor changing from a blocked to a conductive state thereby furnishing said timing signal when the voltage between said base and said emitter reaches a predetermined voltage.

3. A system as set forth in claim 2, wherein said signal furnishing means comprise a first and second switch each having a first state when said distance between said first and second member is said predetermined distance, and a second state when said distance respectively exceeds and is less than said predetermined distance, said first and second switches furnishing said control signal to a first and second terminal respectively when in said second state;

wherein said level varying means comprise first and second level varying means for, respectively, decreasing and increasing said quantity of pressure medium in said suspension system; and

wherein said output circuit means comprise a first output circuit for energizing said first level varying means when said first switch is in said second state and in response to said timing signal and a second output circuit for energizing said second level varying means when said second switch is in said second state and in response to said timing signal.

4. A system as set forth in claim 3, wherein said first and second output circuit respectively comprise a first and second relay and a first and second relay control transistor respectively connected to said first and second relay, each for energizing the corresponding one of said first and second relays when the corresponding one of said first and second switches is in said second state.

5. A system as set forth in claim 4, further comprising holding circuit means for maintaining the energization of said second relay until said second switch switches from said first to said second state.

6. A system as set forth in claim 1, wherein said timing circuit means, said stabilizing circuit means and said output circuit means are mounted in a unit having a plurality of output terminals for connection to said supply means, said level varying means and said signal furnishing means;

further comprising at leaSt one fuse connected between said supply means and the corresponding one of said output terminals, for preventing damage to the circuit means in said unit upon short-circuiting of one of said terminals.