Traction devices for towed vehicles

A traction device for a towable vehicle of a type including an extendable portion adapted to be held to a draft frame, the extendable portion supporting a frame holding two ground engageable wheels, a common lever arm pivotally secured relative to the frame, and drive means to rotate the wheels, the arrangement being characterized according to this invention in that the said drive means comprise in each case a ratchet supported by the lever arm so as to be movable with respect to the arm and engageable in ratchet manner with respect to the wheel, the ratchet being adjustably supported so that in one position of the ratchet, an oscillatory movement of the lever arm about its pivot support will result in rotation of the wheel around in one direction and with the ratchet in a second position, such oscillatory movement of the lever arm will result in rotation of the wheel around in opposite direction to the first said direction, the lever arm being thereby effective to both steer the ground engageable wheel and effect a driving rotation;

• each of the said wheels being differentially rotatable about its central axis and the drive means as characterised exists for each of the said wheels;
• and,
• the ratchet in each case including a spring loaded plunger supported by a pivotally adjustable control arm and a ratchet member pivotally supported and including two engaging tongues positioned to, in one position, engage with one tongue the respective wheel to effect the respective ratchet section in one rotational direction, and in a second position to engage with the other tongue the respective wheel to effect the respective ratchet action in a reverse rotational direction, the ratchet member including a track and the plunger being adapted to engage and slide along the track to hold the ratchet member in either of the two said positions to resiliently hold the respective tongue in a ratcheting position in respect to the wheel.