Patent ID: 8638203

Claim:
An alarm system for an articulated vehicle, comprising: (a) a first part adapted to attach to a vehicular hitch member, the first part including: (i) a first electrical contact and a second electrical contact connected in parallel to an alarm circuit, the first and second electrical contacts being spaced apart in a first horizontal direction, and (ii) a conductive post disposed between the first and second electrical contacts and extending vertically, the post forming a part of the alarm circuit, the post being biased in a first position and moveable between the first position and a second position in which the post contacts the first electrical contact and completes the alarm circuit, and between the first position and a third position in which the post contacts the second electrical contact and completes the alarm circuit, the post including a conductive coil spring and a tensioning mechanism for tensioning the coil spring, wherein tension in the coil spring biases the post in the first position; and (b) a second part adapted to attach to a trailering hitch member, the second part including: (i) a first arm and a second arm independently coupled to the second part and extending in a second horizontal direction towards the post in a common plane at a first adjustable angle with respect to each other, wherein the first and second parts, when attached, are disposed so that the first arm moves the post from the first position to the second position as the articulated vehicle turns in a first direction, and so that the second arm moves the post from the first position to the third position as the articulated vehicle turns in a second direction opposite the first direction.