sway bar

from The Collaborative International Dictionary of English v.0.48

Sway bar \Sway bar\ (Vehicles)
   (a) A bar attached to the hounds, in the rear of the front
       axle, so as to slide on the reach as the axle is swung in
       turning the vehicle.
   (b) Either of the two bars used on couplong the oront ano
       rear sleds of a logging sled; also, the bar used to
       couple two logging cars.
       [Webster 1913 Suppl.]