US 4,430,637 A · Automotive trailer connection recognition system

Abstract

To provide an indication of the presence of a trailer connected to a vehicle, operating as a tractor, without any additional terminal or contact elements on a plug-socket connector between the electrical system of the tractor and the trailer connected thereto, a logic gate (11), preferably a NAND-element, is connected to the output line of the direction flasher circuit, or other suitable connecting line, to a low-resistance load on the trailer, for example the brake light (19a), position lights or the like, the resistance circuit element including a connection from the positive power supply through a resistor (12) having a value which is high with respect to that of the lamps on the trailer (19, 19a) so that, with the trailer disconnected, an effectively 1-signal will be applied to the logic circuit but, upon connection of a low-resistance lamp, that is, upon connection of a trailer socket, the signal at the logic gate will drop to a O-signal although the current through the lamp is insufficient to cause lighting thereof. Energization of the respective flasher lamps, which is only short-time, may cause flashing of the indicator which can be suppressed, for example, by inclusion of an R/C circuit in the control system for the indicator lamp.

Claims16

Dependent claims

Automotive trailer connection recognition system for use with a tractor electrical system comprising:

power supply buses (1, Ch);
a blinker system on the tractor including means (8) generating blinker pulses;
at least two tractor blinker lamps (7) of a first predetermined resistance on the tractor;
a blinker switch (2, 3, 3', 3", 3'") selectively controlling connection of at least one of the blinker lamps (7) to the blinker pulse generator means (8);
a severable trailer connector (10);
at least two trailer blinker lamps (19, 19a) of a second predetermined resistance connected to the trailer connector (10:
connection means (9') connecting the blinker switch means to the trailer connector (10) for severable connection to the trailer blinker lamps;
resistance sensing means (11, 12) connected to said connection means (9') including logic means (11) recognizing a high-resistance or low-resistance condition on said connection means (9') and providing an outtput signal if the resistance sensing means senses a connected low-resistance condition on said connection means;
and mean (5, 6;
22, 23, 24) for isolating the at least two tractor blinker lamps (7) on the tractor from said connection means (9') unless said lamps are energized from said power supply buses (1, Ch).

7 more elements

Dependencies are inferred from the claim text.

Automotive trailer connection recognition system

Life of this patent

Automotive trailer connection recognition system

Life of this patent

Abstract

Claims16