AUXILIARY BRAKING SYSTEM

• US 3,809,191 A
• Filed: 08/25/1971
• Issued: 05/07/1974
• Est. Priority Date: 08/04/1969
• Status: Expired due to Term

• Current Assignee: Herber Jay Woodward
• Original Assignee: Herber Jay Woodward
• Inventors: Woodward, Herber Jay
• Primary Examiner(s): Halvosa, George E. A.
• Application Number:
  US05/174,756
• Time in Patent Office: 986 Days
• Field of Search: 188/16R,16P,16F,16A,158,162,364 60/6,54.6M 92/50,69,75 192/83 74/89.13,89.15,89,520
• US Class Current: 188/106.00A
• CPC Class Codes: B60T 13/741 acting on an ultimate actuator
• CPC Class Codes: B60T 17/22 Devices for monitoring or checking brake systems; Signal devices
• CPC Class Codes: F16D 2121/02 Fluid pressure
• CPC Class Codes: F16D 2121/24 using motors
• CPC Class Codes: F16D 2123/00 Multiple operation forces
• CPC Class Codes: F16D 2125/26 Cranks
• CPC Class Codes: F16D 2125/40 Screw-and-nut
• CPC Class Codes: F16D 2125/52 with non-parallel stationary axes, e.g. worm or bevel gears
• CPC Class Codes: F16D 2125/66 Wedges
• CPC Class Codes: F16D 2125/68 Lever-link mechanisms, e.g. toggles with change of force ratio
• CPC Class Codes: F16D 51/48 with two linked or directly-interacting brake shoes
• CPC Class Codes: F16D 65/22 adapted for pressing members apart , e.g. for drum brakes
• CPC Class Codes: Y10T 74/18792 including worm
• CPC Class Codes: Y10T 74/20588 toggle

Abstract

Electromechanical auxiliary braking systems are provided to supplement hydraulic braking systems. A reversible electric motor drives means for mechanically urging the brake shoes into or out of engagement with the brake drum. In some forms of the present invention, the mechanical means are located within the hydraulic cylinder of the hydraulic brake system and act upon the pistons thereof, while in other forms, the electromechanical system is completely independent of the hydraulic system and acts directly on the brake shoes.

Claims

1. A dual actuation braking system comprising:

opposed brake shoes mounted for movement into and out of engagement with a circumscribing brake drum;

a hydraulic brake cylinder carried between the brake shoes within the brake drum and including opposed pistons hydraulically actuable by pressurized brake fluid applied to a central chamber within the hydraulic brake cylinder by means external thereof to the central chamber to drive said brake shoes into engagement with said drum;

resilient means for urging said brake shoes out of engagement with said drum;

an electric motor mounted adjacent the hydraulic brake cylinder;

an aperture formed in one side of said hydraulic cylinder at the central chamber and intermediate said pistons;

a shaft rotatably coupled to and driven by said motor projecting at a threaded end thereof through said aperture into the central chamber of said cylinder, a seal being interposed between the shaft and the cylinder at the aperture to constrain leakage of brake fluid from the central chamber; and

mechanical means disposed within the central chamber of said cylinder in said brake fluid for movement therein in the presence of brake fluid independent of whether said brake fluid is under pressure or in the absence of fluid in said cylinder because of leakage or the like, said mechanical means being connected within the cylinder by an internally threaded nut to the threaded end of and actuated by said shaft by threaded movement of the nut along the shaft between first and second positions in response to the rotation of said motor, said mechanical means further comprising a pair of drive rods within the cylinder each having one end thereof connected to said nut and the other end thereof mounted to a plate means adjacent to a piston for driving engagement with a respective one of said brake shoes through the pistons, the length of said drive rods being such that, when said nut is moved from said first position to said second position, said drive rods serve to displace the pistons and force said brake shoes into engagement with said drum and hold said engagement until released by said motor.