Trailer brake system
AssigneeStromberg-Hydramite Corporation
InventorWilliam T. Salam
Life of this patent
Estimating the term…
Abstract
A unitary braking system for a towing vehicle and a towed vehicle in which a pneumatic pressure force is added to the towing vehicle's master cylinder generated pressure force for applying the towed vehicle brakes during normal operation, and, upon loss of pressure in the master cylinder brake system due to unintended separation of the towing vehicle and towed vehicle the towed vehicle brakes are automatically applied by a spring controlled or other preloaded mechanical force applied to the towed vehicle's brake system.
Claims1
In a braking system for a towing vehicle having a hydraulic brake system and a towed vehicle having a hydraulic system, the combination of
- a source of hydraulic pressure carried by the towing vehicle,
- a coupling unit carried by a towed vehicle for transmitting hydraulic pressure forces generated in the towing vehicle brake system to the towed vehicle brake system,
- said coupling unit including means for converting hydraulic pressure forces generated in the towing vehicle brake system into a mechanical force, and means for converting the aforesaid mechanical forces into a hydraulic pressure force in communication with the towed vehicle brakes by means of
- a hydraulic pressure port which opens into a closed chamber having a movable piston therein,
- a second closed chamber having a port which is connectable to said hydraulic pressure conduit means,
- said second closed chamber having a movable piston therein,
- mechanical link means extending between the aforesaid movable pistons and effective to generate pressure in the second closed chamber, and thereby the hydraulic pressure conduit means, in response to movement of the movable piston in the first closed chamber in a brake applying direction, and
- return means for returning the second movable piston and mechanical link means to a brake pressure release position upon release of the application of force to the first movable piston,
- a hydraulic pressure line connecting the source of hydraulic pressure to the coupling unit,
- hydraulic pressure conduit means extending from the coupling unit to the towed vehicle brakes,
- a pneumatic/hydraulic force generating unit in the hydraulic pressure conduit means between the coupling unit and towed vehicle brakes,
- said pneumatic/hydraulic force generating unit being carried by the towed vehicle and being located a fixed distance from the coupling unit,
- said pneumatic/hydraulic unit being activated by pressure derived from the coupling unit,
- said pneumatic/hydraulic unit being effective to increase the pressure applied to the towed vehicle brakes upon application to it of pressure from the source of hydraulic pressure carried by the towing vehicle, and
- means for mechanically setting a towed vehicle brakes upon operation of the towed vehicle and the towing vehicle brake system in the event of failure of the hydraulic brake system.
Dependencies are inferred from the claim text.