US3015522A

US3015522A - Automatic safety brake system

Info

Publication number: US3015522A
Application number: US848655A
Authority: US
Inventors: Richard B Spikes
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-10-26
Filing date: 1959-10-26
Publication date: 1962-01-02
Anticipated expiration: 1979-01-02

Description

United States Patent Ofilice 3,015,522 Patented Jan. 2, 1962 3,015,522 AUTOMATIC SAFETY BRAKE SYSTEM Richard B. Spikes, 2421 4th Ave., Los Angeles, Calif. Filed Oct. 26, 1959, Ser. No. 848,655 8 Claims. (Cl. 303-9) The present invention relates to improvements in a braking system, and more particularly to braking systems for wheeled vehicles which provide a reserve braking action in case of damage to the normal braking means.

Many vehicles, such as automobiles, utilize hydraulically actuated brake shoes which frictionally contact brake drums or disks carried by the vehicle wheels in order to stop or slow down the vehicle. When, for any reason, hydraulic pressure is lost, there is a corresponding loss of braking action.

Dual braking systems have been proposed wherein travel of the foot pedal past a designated point will mechanically pull on cables, which will in turn force the brake shoes into contact. The loss in braking efliciency between the hydraulic and mechanical systems i dangerous, and, by giving a false sense of confidence to the driver, is likely to result in serious accidents.

A further objection to the described system is the necessity of design compromises to permit the free run of the actuating cables and to provide the necessary space for the mechanical system.

The present invention contemplates a dual, or doubleacting, braking system which is entirely hydraulically actuated. This provides equal braking efl'iciency for both the primary and secondary or reserve actuating systems, and the flexibility of location possible with hydraulic lines solves the design problems having to do with lack of. space.

It is, therefore, a principal object of the present invention to provide a hydraulic brake system having a primary brake actuating means and a second, reserve hydraulically operated brake actuating means which will automatically take eflect in case of breaks or leaks in the primary por' tion of the system.

Another object of the present invention is to provide a dual braking system having primary and auxiliary hydraulic means for actuating the same brake shoes with a similar degree of efliciency so as to provide a smooth transition from the primary to the auxiliary braking means.

A further object of the invention is to provide a dual braking system of the character described in which the transition from the primary to the auxiliary actuating means is signalled to the foot of the operator to inform him that some flaw exists in the primary system.

A still further object of the present invention is the provision, in a dual braking system of the character set forth, of a valving means which permits the use of a single master cylinder for both systems.

And finally, it is proposed to provide a valving means of the character described which is actuated by travel of the foot pedal or other brake actuating control past a predetermined point, and which will visually signal to the operator that the valving means has operated to cut ofl the primary system and connect the reserve system.

Further objects and advantages of my invention will appear as the specification continues, and the new and useful features of the same will be fully defined in the claims hereto attached.

FIGURE 1 shows a plan schematic view of a dual braking system constructed in accordance with the present invention and applied to a four Wheeled vehicle;

FIGURE 2, an enlarged vertical sectional view of the master cylinder and associated structure taken substantially on the plane of line 22 of FIGURE 1;

FIGURE 3, an enlarged vertical sectional view of the brake assembly and actuating cylinders taken substantially on the plane of line 3-3 of FIGURE 1;

FIGURE 4, an enlarged vertical section view of a valving means taken substantially on the plane of line 4--4 of FIGURE 1; and

FIGURE 5, a plan sectional view of a valving means taken substantially on the plane of line 5-5 of FIG- URE 4.

While I have shown only the preferred form of my invention, I wish to have it understood that various changes or modifications may be made within the scope of the claims hereto attached, without departing from the spirit of the invention.

Referring to the drawing in detail, it will be seen that the brake system of the present invention consists basically of primary and auxiliary brake actuating means 11 and 12, which are operative upon energization to apply friction brakes 16, energizing means 13 for the actuating means which is controlled by a manually operable member 14, and sensing means 17 operable to disconnect the primary brake actuating means 11 from the energizing means 13, and simultaneously connect the auxiliary brake actuating means 12 thereto, upon movement of said member 14 beyond a predetermined range of movement.

FIGURE 1 illustrates the arrangement of parts used in connection with a four wheel vehicle. As here shown, the brakes 16 are of the internally expanding type in which a pair of

brake shoes

18 and 19 are pivoted on pins 21 for outward movement into contact with the inner periphery of a brake drum 22 mounted upon the vehicle wheel (not shown).

The

brake shoes

18 and 19 are urged outwardly by a cam 23 positioned between the confronting free ends of the brake shoes. Rotation of the cam in either direction, from the neutral position illustrated in FIGURE 3, will urge the brake shoes apart and into frictional contact with the brake drum 22.

The primary brake actuating means 11 is designed to rotate the cam 23 in one direction, when energized, while the auxiliary actuating means l2 urges the cam in the opposite direction when the sensing means 17 connects the auxiliary actuating means 12 to the energizing means 13.

As may be best seen from FIGURE 3 of the drawings, the primary actuating means 11 includes a hydraulic cylinder 24 which is supported by the vehicle axle housing (not shown) in position for its piston '26 to displace a lever 27 connected to cam 23 for applying the brakes whenever fluid under pressure is supplied to cylinder 24.

Mounted in aligned opposition to cylinder 24 i a similar cylinder 28 forming part of the auxiliary actuating means 12. The piston 29 of cylinder 28 bears against the side of lever 27 opposite to cylinder, 24 and serves to rotate the cam 23 in the opposite direction whenever fluid under pressure is supplied to cylinder 28.

It will be noted that the

cylinders

24 and 28 are of the same size, and the effective lever arm they employ in rotating cam 23 is the same. This results in identical braking eflect whichever cylinder is operating.

Fluid under pressure is supplied by the energizing means 13, which here consists of a master brake cylinder 31 operated by the usual brake pedal arm 32 providing the manually operable member 14, see FIGURE 2. Preferably, the master brake cylinder 31 is somewhat longer than the conventional unit in order to provide for a somewhat longer travel for the piston 33 in it chamber 34. Otherwise, the construction is conventional and includes a. fluid reservoir 36 and piston return, spring 37.

A supply line 38 communicates the master cylinder chamber 34-with valve means 39 which form a part of the sensing means 17. Preferably, there are two valve means mounted on the front and rear of the vehicle and operative for selectively communicating the supply line 3 38 with either the primary brake actuating cylinders 24 or the auxiliary cylinders 28.

As here shown, the valve means 39 each consists of a two-way valve having a pair of conduits 41 leading to the primary cylinders 24 of the adjacent wheels, and a pair of conduits 42 leading to the auxiliary cylinders 28.

The valves 39 are here or" the rotary type, shown in FIGURES 4 and of the drawings, and consist of a rotor 43 mounted for limited rotation in a housing unit 44. The supply line 38 opens to the hollow center of the rotor 43 from which extends

radial passages

44a and 44b.

The passages 44a are proportioned to register with ports leading to conduits 41, in one terminal position of the valve and passages 44b are formed to register with the conduits 42 in the other terminal position of the valve. The passages 44a are normally aligned with conduits 41, while passages 44b communicate with relief ports 46 through cut-out portions of the rotor. These connections are reversed when rotor 43 is moved to its other terminal position.

Passages

44a and 44b are blocked off when not in registry with their respective conduits and ports 46 may be connected to reservoir 36 through suitable conduits (not shown).

As will be noted from FIGURES 1, 4 and 5 of the drawing, the valves 33 are double two-way valves, that is, there are two ports leading to primary supply lines 41 and two ports leading to auxiliary supply lines 42. This structure insures that opening of either set of ports will be simultaneous and proportional and thus application of the brakes on the opposite sides of the vehicle will be completely balanced at all times.

The sensing means 17 includes means for operating the valve between its terminal positions to shut off fluid from the primary cylinders 24, should they or their supply conduits develop a leak, and to supply the fluid to the auxiliary or reserve cylinders 28. This means here consists of a solenoid 47 adapted to drive a rack gear 48 which is enmeshed with a pinion gear 49 secured to the valve rotor 43. Upon energization of the solenoid, the

rack will move and cause the valve rotor to move to the terminal position actuating the auxiliary cylinders.

The solenoid is connected by

leads

51 and 52 to a source of electrical energy, such as the vehicle battery (not shown). Interposed in one of the leads is a switch 53 which is mounted in the path of travel of the brake pedal 32 or piston 33 so as to be closed when the piston passes a predetermined position in the cylinder chamber 34.

Whenever a predetermined quantity of fluid is lost from the system, the piston 33 will pass the predetermined point and the switch 53 will complete the circuit to the solenoid 47. The loss of fluid may be caused by leakage from any part of the system, but usually occurs due to wear or injury of the wheel cylinders or the flexible conduits leading thereto.

Completing of the circuit to the solenoid 47 will cause the valves 39 to swing to their other terminal position, disconnecting the primary cylinders 24 and their conduits 41 from the pressurized system, and connecting the auxiliary cylinders 28 to the master brake cylinder.

The elfect of this is to cause the cam 23 to swing in the opposite direction and apply the brakes. A light 54, mounted on the dashboard and connected into the solenoid circuit, visually indicates when the reserve brake actuating means comes into play. The operator can also feel the changeover during the tiny period in which the cam 23 swings to its auxiliary braking position.

While the dual braking system has been described for use in connection with four-wheel vehicles, it should be noted that the system is equally effective with vehicles having more or less wheels. When used with multiple wheel units, one valve 39 may conveniently serve each pair of wheels, although other arrangements may be made.

Thus, it will be seen that I have provided a novel double-acting braking system having primary and auxiliary brake actuating cylinders, which will automatically switch from the primary to the auxiliary cylinders upon loss of a certain amount of fluid from the system. This gives the driver complete control of braking under all conditions and even if the primary actuators become inoperative due to breaks or leakage. Such control is an important factor for safety, and may prove the diiference between life or death.

I claim:

1. In a dual braking system for automotive vehicles, a primary hydraulic brake actuating cylinder at each wheel, a master cylinder adapted for producing fluid under pressure upon movement of a piston therein, an auxiliary hydraulic brake actuating cylinder at each wheel, valve means connecting said primary brake actuating cylinders and said auxiliary brake actuating cylinders to said master cylinder in first and second terminal positions respectively of said valve means, and sensing means operatively connected to said piston and adapted for actuating said valve means from said first position to said second position upon movement of said piston past a predetermined point in said cylinder.

2. In a dual braking system for automotive vehicles, a primary hydraulic brake actuating cylinder at each wheel, a master cylinder adapted for producing fluid under pressure upon movement of a piston therein, an auxiliary hydraulic brake actuating cylinder at each wheel, valve means connecting said primary brake actuating cylinders and said auxiliary brake actuating cylinders to said master cylinder in first and second terminalpositions respectively of said valve means, said valve means including electrically powered actuating means for moving said valve means between said terminal positions, and sensing means operatively connected to said piston and adapted for actuating said valve means from said first position to said second postion upon movement of said piston past a predetermined point in said cylinder, said sensing means including an electrical circuit having a switch operable upon said movement of the piston past the predetermined point.

3. In a dual braking system for automative vehicles, a primary hydraulic brake actuating cylinder at each wheel, a master cylinder adapted for producing fluid under pressure upon movement of a piston therein, an auxiliary hydraulic brake actuating cylinder at each wheel, a fluid supply conduit from said master cylinder, a pair of valves positioned in communication with said conduit at the front and rear of the vehicle, said valves being of the two-way type and adapted for selectively connecting said conduit with the primary and auxiliary actuating cylinders of the front and rear sets of wheels respectively, and valve operating means having an operative connection to said piston and formed for controlling said valves to communicate said conduit with said primary actuating cylinders while said piston is positioned in a predetermined portion of said master cylinder and for reversing said valves when said piston is out of said predetermined portion of said master cylinder.

4. In a dual braking system for the wheel of an automotive vehicle having friction brakes for slowing rotation of the wheel, a pair of hydraulic brake actuating cylinders, a master brake cylinder having a fluid supply, a two-Way valve connected to said brake actuating and master cylinders and formed for selectively supplying fluid under pressure from the master cylinder to one of said brake actuating cylinders in one terminal position and to the other actuating cylinder in its other terminal position, and electrically operated means for positioning said valves in one terminal position during normal operating condition of said master cylinder and for positioning said valve in the other terminal position upon depletion of said fluid supply at said master cylinder.

5. A dual braking system of the character described in claim 4 and wherein said two-way valve is of the rotary type, and said electrically operated means is adapted to rotate said valve.

6. A dual braking system of the character described in claim 5 and wherein said electrically operated means includes a rack and pinion drive for said valve, a solenoid connected to said rack, and an electrical switch operable by movement of the piston in said master cylinder beyond a predetermined position.

7. In an automotive vehicle having brake drums carried by each wheel for frictional engagement by outwardly movable brake shoes pivoted on the vehicle, a dual braking system, comprising a cam rotatably mountable between the brake shoes at each wheel and formed to spread such brake shoes when rotated in either direction, an arm extending from said cam for rotating the latter when the arm is displaced from a centered position, primary and auxiliary hydraulic cylinders mounted in confronting relation with said arm interposed therebetween for displacement in a first direction when fluid un- 'er pressure is supplied to said auxiliary cylinder, a master cylinder adapted for producing fluid under pressure upon movement of a piston therein, valve means connecting said primary brake cylinders and said auxiliary brake actuating cylinders to said master cylinder in first and second terminal positions, respectively of said valve means, said valve means including electrically powered actuating means for moving said valve means between said terminal positions, and sensing means operatively connected to said piston and adapted for actuating said valve means from said first position to said second position upon movement of said piston past a predetermined point in said master cylinder, said sensing means including an electrical circuit having a switch operable upon said movement of the piston past the predetermined point.

8. A dual braking system as defined in claim 7, and wherein said valve means includes a valve having a rotor movable between terminal position and formed with passages adapted for communicating said master cylinder with said primary cylinder during the first position of the stroke of said piston and with said auxiliary cylinder upon a continuing portion of said stroke whereby the changeover from said primary to said auxiliary cylinder will release the brakes for a tiny instant and thus signal the driver that the system has switched to auxiliary braking.

References Cited in the file of this patent UNITED STATES PATENTS 1,650,286 Livingston Nov. 22, 1927 2,464,469 Tremolada Mar. 15, 1949 2,649,169 Holman Aug. 18, 1953 2,871,827 Euga Feb. 3, 1959