1956 Packard Panther Project

1958 Allison "Interdependent" torsional system

William D. Allison, a Hudson engineer, invented a unique torsion bar suspension system before World War II. In 1947 he demonstrated it to Packard because Hudson did not have the finances to develop his new system. In 1951, an intensive development program by Packard and Mr. Allison (now a Packard employee). It culminated with the introduction of Torsion-Level Suspension in the 1955

(Illustration from "Packard Master Serviceman's Training Book.")

Basically, the entire car "floats" on four points, the front & rear opposite twist lever arms of two long (106" in Juniors, 111" in Seniors) torsion bars, one on each side. The major advantage of this arrangement is that any reaction at the wheel, such as hitting a bump or pothole, is transmitted to the opposite wheel (front or rear) and NOT the frame, greatly reducing twisting stress on the frame. Another positive effect to wheel reaction is that the opposite (front or rear) wheel reacts in the opposite direction, tending to keep the car dynamically level, in other words, very little pitch is experienced, if the shocks are in good condition.

Two additional short (46" in Juniors, 51" in Seniors) torsion bars connect the rear suspension with a levelizer mechanism. This electro-mechanical system, after a 7-10 second delay, applies more or less twist to the short torsion bars which lift or lower the rear. This keeps the car statically level, compensating for loaded weight such as additional passengers and/or luggage in the trunk.

Explanation continued...
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