Hensley Arrow: How does it REALLY work?
There have been several discussions on this hitch that have become somewhat 'controversial'. I am NOT trying to stir this controversy/bashing back up. Instead, I'd like to see a good, intelligent di...
Forum Discussion
MacMan wrote:
Since the connection is "virtually" solid, couldn't it be considered that the "virtual pivot point" is non-existant, due to the excessive force that would be required to cause the Hensley to pivot at its hitch point when being reacted upon by the TT?
The 4-bar linkage connection is not "virtually" solid. It is not rigid in any sense. You would have to add a diagonal link to transform it into two triangles to make it rigid. The whole point of using a 4-bar linkage is to allow the orange portion to translate and rotate relative to the black portion or vice versa.
I think the most difficult thing to grasp in this discussion is the fact that, while the orange portion does translate and rotate, the effective pivot point is some 47" forward when the TT and TV are aligned straight ahead. The linkage does not prevent the orange portion from moving. The linkage does require that, in order for the orange portion to move to the side, it must simultaneously rotate.
A PullRite hitch produces the same result. In order for the hitch head to move to the side, the PR's draw bar must pivot about its pin. In fact, everything that is rigidly connected to the PR's draw bar must simultaneously translate and rotate if it is to move at all. The rotation (yaw angle) is the same at all points. The amount of translation is proportional to the distance from the pivot point.
It is not the HA's linkage which prevents the TT from swinging behind the TT. It is the lateral force on the TT's tires. Take the tire side force away and the TT can swing freely.
A main point to remember is that when the TT and TV are aligned straight ahead (or within several degrees) the pivot point is not at the hitch head.
Ron
