초록 ▼

There is disclosed a theft prevention system for trailers with the customary pneumatic trailer braking system. A normally closed solenoid valve is connected in the line that supplies air to release the trailer parking brakes and a signal receiver adapted to receive an electrical signal from a transm

There is disclosed a theft prevention system for trailers with the customary pneumatic trailer braking system. A normally closed solenoid valve is connected in the line that supplies air to release the trailer parking brakes and a signal receiver adapted to receive an electrical signal from a transmitter in the tractor cab must be caused to actuate the solenoid to open the valve to release the trailer parking brakes. The signal from the transmitter to the receiver may be transmitted over the electrical cable from tractor to trailer or may be a radio transmitted signal . The solenoid valve is provided with a pneumatic latch so that the parking brakes will remain released as long as air pressure is provided. The signal transmitter is provided with security to prevent unauthorized use which may be a key switch, a key pad for entry of an identification number, a magnetic strip card reader or other device. The solenoid valve and receiver are secured in a locked cabinet and a by pass valve is also located within the cabinet. The receiver may be programed to require the lights to be turned on in whole or in part or sequentially to release the brakes.

대표청구항 ▼

1. In a tractor-trailer transport vehicle having a tractor with a cab, a trailer, electrical cables and connectors therebetween, said tractor having an air pressure operated brake system with air pressure supply means and a parking air supply line to a parking brake air line of said trailer, a safet

1. In a tractor-trailer transport vehicle having a tractor with a cab, a trailer, electrical cables and connectors therebetween, said tractor having an air pressure operated brake system with air pressure supply means and a parking air supply line to a parking brake air line of said trailer, a safety and security system comprising:an electric signal transmitter installed in said cab; a signal receiver in said trailer adapted to detect signals from said transmitter and produce a low voltage output; a solenoid valve in said trailer responsive to be activated by a low voltage DC output from said signal receiver and adapted to open a normally closed valve from said parking brake air line to said parking air supply line, wherein said solenoid valve includes a latch element responsive to high pressure air in said parking brake line to hold said normally closed valve in an open position in response to a predetermined minimum air pressure in said parking brake air line; whereby the parking brakes of said trailer can only be released when an appropriate signal is transmitted from said cab-installed transmitter.