Hydraulic brake actuator for trailers

Claim 2

A hydraulic brake actuator for a wheeled trailer connected to a towing vehicle, said towing vehicle being provided with brakes and said trailer being provided with hydraulic brakes, comprising: a hitch means connecting said trailer with said towing vehicle; a master brake cylinder mounted on said trailer for producing hydraulic fluid pressure, said master cylinder including a piston movable in one direction in a cylindrical space to produce said hydraulic fluid pressure and said piston being movable by engagement with a plunger; means for transmitting said hydraulic fluid pressure to said trailer brakes; and means associated with said hitch for causing said master brake cylinder to produce hydraulic fluid pressure upon relative movement between said towing vehicle and said trailer in either direction while said hitch remains connected to said vehicle, said means being constructed and arranged to move said plunger toward said master cylinder when relative movement between said towing vehicle and said trailer takes place in oNe direction and to move said master cylinder toward said plunger when said relative movement takes place in the opposite direction.

Claim 3

A hydraulic brake actuator as defined in claim 1, wherein said means associated with said hitch means includes resilient means opposing movement of said plunger toward said master cylinder and also opposing movement of said master cylinder toward said plunger.

Claim 4

A hydraulic brake actuator as defined in claim 1, including lever means for manually moving said plunger toward said master cylinder.

Claim 5

A hydraulic brake actuator as defined in claim 3, including: chain means connectable between said lever means and said towing vehicle for moving said lever means to move said plunger in the event of failure or disconnection of said hitch means; and ratchet means for maintaining said lever means in a position to which said lever means is moved.

Claim 6

A hydraulic brake actuator as defined in claim 1, including: a shaft formed as a part of said hitch means, one end of said shaft being connected to said towing vehicle and said shaft having a rearwardly facing shoulder; bearing means for said shaft mounted on a frame of said trailer; front plate means normally abutting the rear of said bearing means and engageable by said shaft shoulder; rear plate means to which said master cylinder is affixed so as to be movable therewith, said rear plate means being connected to the opposite end of said shaft; guide means for movement of said master cylinder generally parallel to said shaft and constructed and arranged to restrict rearward movement of said master cylinder beyond a predetermined point; resilient means urging said front plate means and said rear plate means apart; and said plunger means being movable rearwardly by said front plate means and said master cylinder being movable forwardly by said rear plate means.

Claim 7

A hydraulic brake actuator for a wheeled trailer connected to a towing vehicle, said towing vehicle being provided with brakes and said trailer being provided with hydraulic brakes, comprising: a hitch means connecting said trailer with said towing vehicle; a master brake cylinder mounted on said trailer for producing hydraulic fluid pressure; means associated with said hitch for causing said master brake cylinder to produce hydraulic fluid pressure upon relative movement between said towing vehicle and said trailer in either direction while said hitch remains connected to said vehicle; means for transmitting said hydraulic fluid pressure to said trailer brakes; means for controlling the transmission of said hydraulic fluid pressure to said trailer brakes responsive to the application of the brakes of said towing vehicle; means connectable with said towing vehicle for independently causing said master brake cylinder to produce hydraulic fluid pressure upon breakage or disconnection with said hitch means, whereby said trailer becomes detached from said towing vehicle; and means associated with said transmitting means and responsive to a predetermined pressure, in excess of that normally produced in applying said trailer brakes, for permitting transmission of said hydraulic fluid pressure from said master cylinder to said trailer brakes when said pressure exceeds said predetermined pressure, said pressure responsive means being independent of said controlling means responsive to the application of said towing vehicle brakes.

Claim 8

A hydraulic brake actuator for a wheeled trailer connected to a towing vehicle, said towing vehicle being provided with brakes and said trailer being provided with hydraulic brakes, comprising: a hitch means connecting said trailer with said towing vehicle; a master brake cylinder mounted on said trailer for producing hydraulic fluid pressure; means associated with said hitch for causing said master brake cylinder to produce hydraulic fluid pressure upon relative movement between said towing vehicle and said trailer in either direction while said hitch remains connected to said vehicle; means for transmitting said hydraulic fluid pressure to said trailer brakes; means for controlling the transmission of said hydraulic fluid pressure to said trailer brakes responsive to the application of the brakes of said towing vehicle; means connectable with said towing vehicle for independently causing said master brake cylinder to produce hydraulic fluid pressure upon breakage or disconnection with said hitch means, whereby said trailer becomes detached from said towing vehicle; and means associated with said transmitting means and responsive to a predetermined pressure, in excess of that normally produced in applying said trailer brakes, for permitting transmission of said hydraulic fluid pressure from said master cylinder to said trailer brakes when said pressure exceeds said predetermined pressure, said pressure responsive means being independent of said controlling means responsive to the application of said towing vehicle brakes.

Claim 9

In a hydraulic brake actuator as defined in claim 6 including: a housing having an inlet passage connected with said master brake cylinder and an outlet passage connected with said trailer brakes; means for controlling the transmission of said hydraulic fluid pressure to said trailer brakes responsive to the application of the brakes of said towing vehicle, said towing vehicle being provided with a stop light controlled through an electrical circuit and said controlling means including a plunger movable by an elEctrical solenoid connectable to the stop light circuit, whereby hydraulic fluid pressure is transmitted to said trailer brakes through said controlling means only when said towing vehicle brakes are applied; said controlling means including a valve normally covering a port between said inlet passage and said outlet passage and said valve being movably mounted on a stem connected to said solenoid plunger, so that said valve will normally be held against said port by pressure in said inlet passage but will be forced off said port when the pressure in said outlet passage exceeds the pressure in said inlet passage; and said means responsive to a predetermined pressure includes a relief valve controlling flow between said inlet passage and said outlet passage through a separate port in said housing and resilient means urging said relief valve toward a seat.