Electric motorized brake-lock system

• US 5,505,528 A
• Filed: 10/03/1994
• Issued: 04/09/1996
• Est. Priority Date: 01/13/1993
• Status: Expired due to Term

• Current Assignee: MICO, Inc. (Wabco Holdings Incorporated)
• Original Assignee: MICO, Inc. (Wabco Holdings Incorporated)
• Inventors: Bangert, Terry M., Hamman, Seth W.
• Primary Examiner(s): Graham, Matthew C.
• Application Number:
  US08/316,822
• Time in Patent Office: 554 Days
• Field of Search: 303/10, 303/11, 303/DIG. 1, 303/DIG. 2, 303/DIG. 3, 303/DIG. 4, 303/116.1, 303/116.2, 303/116.4, 303/9, 303/9.61, 303/9.63, 303/89, 303/84.2, 303/6.1, 188/353, 188/265, 180/273, 180/286
• US Class Current: 303/89
• CPC Class Codes: B60R 25/08 operating on brakes or brake systems
• CPC Class Codes: B60T 11/18 Connection thereof to initiating means
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: B60T 17/16 Locking of brake cylinders
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00

Abstract

An automatic vehicle brake locking system, including an actuator (16) which segregates an auxiliary hydraulic fluid pump (42) from the normally used vehicle master cylinder (2). The actuator (16) is formed as a cylinder including a piston (36) which is biased to permit passage of hydraulic fluid which is pressurized by the vehicle master cylinder (2) through the actuator (16).

Claims

1. A method of automatically activating vehicle brakes in a vehicle of the type having a primary braking control system including a master cylinder for providing hydraulic pressure to control the vehicle brakes, the method comprising the steps of:

(a) fully pressurizing the vehicle brakes in response to a first predetermined vehicle operating condition, wherein the primary braking control system is removed from control of the vehicle brakes, and wherein the fully pressurizing step includes the steps of;

(i) activating an auxiliary hydraulic fluid pump to provide a source of pressurized hydraulic fluid;

(ii) segregating the master cylinder from the vehicle brakes in response to the pressurized hydraulic fluid, wherein the primary braking control system is not operatively connected to the vehicle brakes;

(iii) applying pressure to the vehicle brakes in response to the pressurized hydraulic fluid; and

(iv) deactivating the auxiliary hydraulic fluid pump when the vehicle brakes are fully pressurized; and

(b) fully de-pressurizing the vehicle brakes in response to a second predetermined vehicle operating condition, the fully de-pressurizing step including the step of returning control of the vehicle brakes to the primary braking control system by activating the auxiliary hydraulic fluid pump in reverse to withdraw hydraulic fluid pressure and operatively reconnect the master cylinder to the vehicle brakes.

2. The method of claim 1, further comprising the step of providing a first and second actuator, the first actuator for segregating the master cylinder from a first set of vehicle brakes and the second actuator for segregating the master cylinder from a second set of vehicle brakes.

3. The method of claim 2, further comprising the step of activating an audible alarm when the first vehicle operating condition occurs when hydraulic fluid pressure is below a predetermined value, whereby an operator is alerted that the brakes may not be fully pressurized.

4. The method of claim 3, further comprising the step of delaying the activation of the audible alarm upon initial activation of the auxiliary hydraulic fluid pump.

5. The method of claim 4, further comprising the step of monitoring hydraulic fluid pressure in the first set of vehicle brakes and comparing that pressure to the hydraulic pressure in the second set of vehicle brakes.

6. The method of claim 5, further comprising the step of continuously monitoring hydraulic fluid pressure during activation of the braking system, and activating the auxiliary hydraulic fluid pump in response to hydraulic fluid pressure dropping below a predetermined value.

7. An apparatus for pressurizing vehicle brakes while segregating a vehicle brake master cylinder from the vehicle brakes in response to pressure applied by an auxiliary automatic braking system hydraulic fluid source, the apparatus comprising:

(a) a cylinder, the cylinder having at least a first and second inlet orifice and at least a first outlet orifice;

(b) at least one piston, the piston residing in the cylinder and forming a seal with the cylinder to restrict fluid flow between the piston and cylinder, the seal including a pair of oppositely disposed and spaced apart u-cup seals substantially circumscribing the piston, the u-cup seals restricting fluid flow in opposing directions, the piston being aligned so as to permit opening and closing of the first inlet orifice in response to movement of the piston, and wherein the seal further includes a secondary seal circumscribing the piston and interposed between the u-cup seals;

whereby the secondary seal is configured to maintain a seal between the piston and cylinder in the event of a failure of either u-cup seal; and

(c) a first biasing spring, the first biasing spring being arranged about the piston so as to urge the piston to open the first inlet orifice, the application of hydraulic fluid from an auxiliary hydraulic fluid source to a second inlet orifice tending to counteract the effect of the first biasing spring and close the first inlet orifice, wherein the vehicle brake master cylinder is operatively connected to the first inlet orifice such that the master cylinder is operatively disengaged from control of the vehicle brakes when the first inlet orifice is closed by the piston.

8. The apparatus of claim 7, wherein the first inlet orifice is in fluid communication with the first outlet orifice when the first inlet orifice is opened by action of the first piston.

9. The apparatus of claim 8, wherein the piston has a spring loaded stem movable within the piston, the stem having means for sealing the first inlet orifice.

10. The apparatus of claim 9, wherein hydraulic fluid from an auxiliary brake locking system is supplied through the second inlet orifice, thereby closing the first inlet orifice, applying pressure through the piston and to the first outlet orifice, and permitting the auxiliary hydraulic fluid source to activate the vehicle brakes independently of vehicle brake master cylinder operation.

11. The apparatus of claim 10, further comprising a third inlet orifice and a second outlet orifice, the second outlet orifice being fluidly connected to a second set of vehicle brakes, wherein the at least one piston includes a first and second piston, the first and second outlet orifices being pressurized by the auxiliary hydraulic fluid source providing fluid through the second inlet orifice when the first and third inlet orifices are closed by operation of the first and second pistons residing within the cylinder, respectively.

12. In a closed hydraulic primary vehicle braking control system of the type having a master cylinder for providing hydraulic pressure to control hydraulically actuated brakes on the vehicle, a supplemental vehicle brake locking system comprising:

(a) a reversible auxiliary hydraulic pump for providing a pressurized auxiliary hydraulic fluid;

(b) isolating means, operatively interposed in a hydraulic circuit between the master cylinder and the brakes and operatively configured to receive the pressurized auxiliary hydraulic fluid, for isolating the master cylinder from the brakes when the auxiliary hydraulic fluid exceeds a predetermined pressure;

(c) auxiliary pressurizing means, operatively connected to receive the pressurized auxiliary hydraulic fluid, for pressurizing the brakes when the master cylinder is isolated from the brakes; and

(d) a controller, operatively connected to the auxiliary hydraulic pump and being selectable to operate in first and second operating configurations responsive to a predetermined vehicle operating condition, wherein when the controller is placed in the first operating configuration, the controller activates the auxiliary hydraulic pump to isolate the master cylinder from the brakes and fully pressurize the brakes, and wherein when the controller is placed in the second operating configuration, the controller activates the auxiliary hydraulic pump in reverse to de-pressurize the brakes and reconnect the master cylinder to the brakes.

13. The system of claim 12, wherein the isolating means and the auxiliary pressurizing means are disposed in at least one actuator, the at least one actuator including:

(a) a cylinder having first and second inlet orifices and an outlet orifice; and

(b) a piston residing in the cylinder and aligned so as to permit opening and closing of the first inlet orifice in response to movement of the piston, the piston being biased to urge the piston to open the first inlet orifice, wherein the application of pressurized auxiliary hydraulic fluid from the auxiliary hydraulic pump to the second inlet orifice tends to urge the piston to close the first inlet orifice and apply hydraulic pressure to the outlet orifice.

14. The system of claim 13, wherein the at least one actuator comprises first and second actuators, the first actuator having an output orifice operatively connected in fluid communication with a first set of vehicle brakes and the second actuator having an output orifice operatively connected in fluid communication with a second set of vehicle brakes.

15. The system of claim 12, further comprising first and second pressure sensors, operatively connected to sense the pressure of the pressurized auxiliary hydraulic fluid, the first pressure sensor for determining whether the pressurized auxiliary hydraulic fluid exceeds a first predetermined pressure, and the second pressure sensor for determining whether the pressurized auxiliary hydraulic fluid is below a second predetermined pressure, wherein the controller is operatively configured to receive signals from the first and second pressure sensors such that when the controller is placed in the first operating configuration, the controller de-activates the auxiliary hydraulic pump when the pressure of the pressurized auxiliary hydraulic fluid exceeds the first predetermined pressure, and such that when the controller is placed in the second operating configuration, the controller de-activates the auxiliary hydraulic pump when the pressure of the pressurized auxiliary hydraulic fluid falls below the second predetermined pressure.

16. The system of claim 12, wherein the predetermined vehicle operating condition is selected by means of an on/off switch such that the controller is placed in the first operating configuration upon closure of the switch and placed in the second operating configuration upon opening of the switch.

17. The system of claim 12, wherein the predetermined vehicle operating condition is selected by means of door interlock switch such that the controller is placed in the first operating configuration upon opening of a vehicle door and placed in the second operating configuration upon closing of the door.

18. The system of claim 12, wherein the predetermined vehicle operating condition is selected by means of a deadman switch such that the controller is placed in the first operating configuration upon an operator becoming dislodged from a normal operating position and placed in the second operating configuration upon the return of an operator to the a normal operating position.

19. The system of claim 12, further comprising an audible alarm configured to be activated by the controller when the controller is in the first operating configuration and hydraulic pressure is below a predetermined operating pressure.

20. The system of claim 19, wherein the controller is configured to delay activation of the audible alarm upon initial activation of the auxiliary hydraulic pump.

21. The system of claim 12, further comprising a visual status indicator configured to be activated by the controller when the hydraulically actuated brakes are pressurized to a predetermined operating pressure.

22. The system of claim 12, further comprising:

(a) front and rear brake activation lines, the front brake activation lines controlling operation of front brake cylinders and the rear activation lines controlling operation of rear brake cylinders; and

(b) a warning valve, operatively connected to the front and rear brake activation lines, for sensing a difference in hydraulic fluid pressure between the front rear brake activation lines.