Hensley Arrow: How does it REALLY work?

willald wrote:
And, as I said, the point where that advantage goes away, will almost NEVER happen, due to the Hensley's design, and the path through which it pivots. It could happen if there was no tension between the tow vehicle and trailer, and I think thats the point we really need to keep in mind here, thats been overlooked before.

Yes, the PullRite has a fixed point location, and behaves just like a 5er. This gives great stability, too, and perhaps a bit less complex. However, it does NOT give the same effect of 'locking' the trailer in a straight line, like the Hensley does.

Will

Well, Will, let me try another approach.

When the HA-equipped TT and TV are aligned straight ahead, the HA's two side links, if extended forward, would converge at a point located on the TV's centerline and about 47" ahead of the ball coupler. So, lets just replace the two 5"-long side links and the HA's lower (front) unit with two 47"-long side links which converge at the same angle and are attached to each other at their front ends and to the TV via a pinned connection.

In essence, we have just converted the HA to a PullRite. Instead of having a 4-bar linkage, we now have the TT attached to the TV via a rigid triangle (an "A-frame") attached to a pivot point 47" ahead of the ball. For the "aligned straight ahead" condition, the HA's 4-bar linkage functions as though it were a 47"-long extension of the TT's tongue with a pivot point at the front end. Kinematically, it functions the same as a PR hitch and, as you have agreed, the PR does not have any "locking" effect. Neither does the HA.

The "pulling tension" on a conventionally coupled TT does not "lock" it from swinging; the "pulling tension" on a PR-coupled TT does not "lock" it from swinging; and the "pulling tension on a HA-coupled TT does not "lock" it from swinging. On all TTs, it is only the lateral force on the tires and the TT's inertia which control the swinging.

Ron