| 摘要 |
Herein disclosed a theft prevention system for trailers using the customary pneumatic trailer braking system having spring applied parking brakes that apply when in absence of in an air pressure supply line to the trailer. A normally closed solenoid valve is connected in series with the pressurized air supply line that supplies air to release the trailer parking brakes and a keypad/transmitter on the trailer body must be caused to actuat e the solenoid valve to release the trailer parking brakes. The solenoid valve is preferably provided with a pneumatic latch so that the parking brakes will remain released as long as air pressure is provided to the trailer once the system is disarmed properly , by an authorized operator, by appropriate security means to prevent unauthorized u se wich may be key pad for entry of an identification number.
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