FOUR WHEEL SKID CONTROL SYSTEM

• US 3,768,874 A
• Filed: 04/05/1972
• Issued: 10/30/1973
• Est. Priority Date: 04/05/1972
• Status: Expired due to Term

• Current Assignee: Hugh E. Riordan
• Original Assignee: Hugh E. Riordan
• Inventors: Riordan, Hugh E.
• Primary Examiner(s): Buchler, Milton
• Assistant Examiner(s): Kunin, Stephen G.
• Application Number:
  US05/182,188
• Time in Patent Office: 573 Days
• Field of Search: 188/181 303/20,21 317/5 324/160-162 340/52R,52B,262,263
• US Class Current: 303/188
• CPC Class Codes: B60T 8/17613 based on analogue circuits or digital circuits comprised of discrete electronic elements

Abstract

A four wheel skid control system in which the operation of a first wheel through skid control apparatus controls the basic brake pressure and a second wheel, during skid control, utilizes the controlled basic brake pressure to maintain maximum retarding force while a third wheel utilizes the controlled basic brake pressure and follows the speed of the first wheel and a fourth wheel utilizes the controlled basic brake pressure and follows the speed of the second wheel.

Claims

1. In a skid control system for controlling the fluid pressure provided to the brakes of at least two wheels of a wheeled vehicle, said system comprising:

first speed sensing means for sensing the wheel speed of the first of said wheels and for providing a first wheel speed signal representative of the wheel speed of the first of said wheels, second speed sensing means for sensing the wheel speed of the second of said wheels and for providing a second wheel speed signal representative of the wheel speed of the second of said wheels, detection means for detecting the occurrence of an incipient skid condition at the first of said wheels and for providing a control signal in response thereto, first control means for modulating the pressure provided to the brakes of the first of said wheels in response to said control signal, and second control means receiving said first and second wheel speed signals connected with the brakes of the second of said wheels for modulating the pressure provided to the brakes of the second of said wheels without modulating the pressure provided to the brakes of the first of said wheels to control the speed of the second of said wheels in accordance with the first speed signal during said modulating of the pressure to the brakes of the first of said wheels in response to the detected occurrence of an incipient skid condition.

2. The system of claim 1, with said first and second wheel brakes being operative from a common fluid system.

3. The system of claim 2 with said second control means comprising a cut-off valve for blocking the brakes of the second of said wheels from the common fluid system when the speed of the first and second wheel speed signals reach a preselected relationship.

4. The system of claim 3 with said common system including a common power booster and with said preselected relationship being when the second wheel speed signal of the second of said wheels falls below the first wheel speed signal.

5. The system of claim 4 further comprising third and fourth of said wheels having brakes all operative from the common system and further comprising third speed sensing means for sensing the wheel speed of the third of said wheels and for providing a third wheel speed signal representative of the wheel speed of the third of said wheels, fourth speed sensing means for sensing the wheel speed of the fourth of said wheels and for providing a fourth wheel speed signal representative of the wheel speed of the fourth of said wheels, third control means for controlling the speed of the fourth of said wheels in accordance with the speed of the third of said wheels.

6. The system of claim 5 comprising fourth contrOl means operative on the pressure as determined by said first control means and with the third of said wheels for maintaining the deceleration of the third of said wheels at a magnitude to optimize retarding force.

7. The system of claim 6 with said third and fourth control means each including a cut-off valve operative for blocking fluid pressure from the common fluid system to the brakes of third and fourth of said wheels, respectively.

8. The system of claim 7 with said third control means operative with its said cut-off valve to maintain the speed of the fourth of said wheels proximate that of the third of said wheels.

9. The system of claim 8 with said second control means including first comparator means to provide a signal to actuate the associated said cut-off valve when the speed of the second of said wheels falls below the first and with said third control means including second comparator means to provide a signal to actuate the associated said cut-off valve when the speed of the fourth of said wheels exceeds the speed of the third of said wheels.

10. The system of claim 2 further comprising third and fourth wheels having brakes all operative from the common system and further comprising third speed sensing means for sensing the wheel speed of the third wheel and for providing a third wheel speed signal representative of the third of said wheels, fourth speed sensing means for sensing the wheel speed of the fourth of said wheels and for providing a fourth wheel speed signal representative of the fourth of said wheels, third control means for controlling the speed of the fourth of said wheels in direct accordance with the speed of the third of said wheels.

11. The system of claim 10 comprising fourth control means operative on the pressure as determined by said first control means and responsive to the third wheel speed signal for maintaining the deceleration of the third of said wheels at a magnitude to optimize retarding force.

12. The system of claim 11 with said third and fourth control means each including a cut-off valve operative for blocking fluid pressure from the common fluid system to the brakes of the third and fourth of said wheels, respectively.

13. In a skid control system for controlling the fluid pressure to the brakes of at least two wheels of a wheeled vehicle which are operative from a common fluid system including a common power booster, said system comprising:

first detection means for detecting the occurrence of an incipient skid condition at the first of said wheels and for providing a first control signal in response thereto, first control means for modulating the pressure to the brakes of the first and second of said wheels from said common fluid system in response to said first control signal, and second control means connected with the second of said wheels comprising a cut-off valve for blocking the brakes of the second of said wheels from the common fluid system where the speed of the second of said wheels attains a preselected relationship with the speed of the first of said wheels during said modulating of the pressure to the brakes of the first of said wheels in response to the detected occurrence of an incipient skid condition, said second control means including first comparator means to provide a signal to actuate said cut-off valve when the speed of the second of said wheels attains said preselected relationship with the speed of the first of said wheels.

14. The system of claim 13 further including:

third and fourth wheels all operative from the common system, second detection means for detecting the occurrence of an incipient skid condition at the third of said wheels and for providing a second control signal in response thereto, third control means for affecting the pressure to the brakes of the third of said wheels from said common fluid system in response to said second control signal, and fourth control means for controlling the speed of the fourth of said wheels in accordance with the speed of the third of said wheels, said fourth control means including a cut-off valve operative for blocking fluid pressure from the common fluid system.

15. The system of claim 14 wherein said fourth means is operative with its cut-off valve to maintain the speed of the fourth of said wheels in a predetermined relationship with the speed of the third of said wheels.

16. The system of claim 15 wherein said fourth control means includes second comparator means to provide a signal to actuate the associated cut-off valves when the speed of the fourth of said wheels attains said predetermined relationship with the speed of the third of said wheels.

17. In a skid control system for controlling the fluid pressure provided to the brakes of at least two wheels of a wheeled vehicle, said system comprising:

first speed sensing means for sensing the wheel speed of the first of said wheels and for providing a first wheel speed signal representative of the wheel speed of the first of said wheels, second speed sensing means for sensing the wheel speed of the second of said wheels and for providing a second wheel speed signal representative of the wheel speed of the second of said wheels, first control means including detection means for detecting the occurrence of an incipient skid condition at the first of said wheels for providing a first control signal in response thereto, said first control means including means for controlling the pressure provided to the brakes of the first of said wheels in response to said first control signal, and second control means receiving said first and second wheel speed signals for comparing said first and second wheel speed signals and for providing a second control signal in accordance with a relationship between said first and second wheel speed signals, said second control means including means receiving said second control signal for controlling the pressure provided to the brakes of the second of said wheels, said second control means being adapted for controlling the pressure provided to the brakes of the second of said wheels without delay so that said second control means can control the pressure provided to the brakes of the second of said wheels during the initial period of said modulation of the pressure to the brakes of the first of said wheels in response to the detected occurrence of an incipient skid condition.

18. In a skid control system for controlling the fluid pressure to the brakes of at least two wheels of a wheeled vehicle which are operative from a common fluid system including a common power booster said system comprising:

detection means for detecting the occurrence of an incipient skid condition at the first of said wheels and for providing a control signal in response thereto, first control means for modulating the pressure to the brakes of the first of said wheels in response to said control signal, second control means connected with the second of said wheels comprising a cut-off valve for blocking the brakes of the second of said wheels from the common fluid system when the speed of the second of said wheels exceeds that of the first, during said modulating of the pressure to the brakes of the first of said wheels in response to the detected occurrence of an incipient skid condition, third and fourth of said wheels all operative from the common system, said second control means including first comparator means to provide a signal to actuate the associated said cut-off valve when the speed of the second of said wheels exceeds the first, third control means for controlling the speed of the fourth of said wheels in accordance with the speed of the third of said wheels, and fourth control means operative on the pressure as directed by said first control means and with the third of said wheels for maintaining the deceleration of the third of said wheels at a magnitude to optimize retarding force, said third and fourth control means each including a cut-off valve operative for blocking fluid pressure from the common fluid system, said Third means operative with its said cut-off valve to maintain the speed of the fourth of said wheels proximate that of the third of said wheels, said third control means including second comparator means to provide a signal to actuate the associated said cut-off valve when the speed of the fourth of said wheels exceeds the speed of the third of said wheels.

19. In a skid control system for controlling the fluid pressure provided to the brakes of at least two wheels of a wheeled vehicle, said system comprising:

first speed sensing means for sensing the wheel speed of the first of said wheels and for providing a first wheel speed signal representative of the wheel speed of the first of said wheels, second speed sensing means for sensing the wheel speed of the second of said wheels and for providing a second wheel speed signal representative of the wheel speed of the second of said wheels, first control means including detection means for detecting the occurrence of an incipient skid condition at the first of said wheels for providing a first control signal in response thereto, first modulating means for modulating the pressure provided to the brakes of the first of said wheels in response to said first control signal, second control means receiving said first and second wheel speed signals for comparing said first and second wheel speed signals and for providing a second control signal in accordance with a difference in said first or second wheel speed signals, and second modulating means receiving said second control signal for modulating the pressure provided to the brakes of the second of said wheels, said skid control means being adapted for controlling the modulation of the pressure provided to the brakes of the second of said wheels without controlling the modulation of the pressure provided to the brakes of the first of said wheels during said modulation of the pressure to the brakes of the first of said wheels in response to the detected occurrence of an incipient skid condition.

20. In a skid control system for controlling the fluid pressure to the brakes of at least two wheels of a wheeled vehicle which are operative from a common fluid system including a common power booster, said system comprising:

first detection means for detecting the occurrence of an incipient skid condition at the first of said wheels and for providing a first control signal in response thereto, first control means for modulating the pressure to the brakes of the first and second of said wheels from said common fluid system in response to said first control signal, and second control means connected with the second of said wheels comprising a cut-off valve for blocking the brakes of the second of said wheels from the common fluid system when the speed of said wheels indicates the occurrence of an incipient skid condition at the second of said wheels.