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
I like that Tim. The Hensley may not be a 4-bar linkage, it may only be a 2-bar linkage, in that only 2 bars can move. Your demonstration allows the upper and lower bars to pivot freely, but on the hitch, this is not allowed by virtue of a lot of steel, and the geometry of the links.
A more appropriate demonstration would occur if you grasped the top bar, (TV), in your left hand, and the bottom bar, (TT), in your right hand, and then, pulling outward with both hands, tried to turn the ends of either one in towards the other. If the geometry is correct, only the bar with the shortest distance between the pivot points will allow a "Turn" to occur.
On the hitch, suspended from the TV, this is simulated by grasping the weight distribution bars or the strut connecting pins, leaning back, and pulling less on one side than the other. On a true 4-bar, that you have demonstrated, this would result in a turn, but on the Hitch, it does not.
And in the interest of helping clarify the VPP concept, it is useful in explaining how the TT tracks behind the TV, and why the trailer backs up the way it does. It is also useful in explaining where the side loads are felt when the trailer attempts to shift its angle relative to the Tow vehicle because it represents one end of a lever.
Reversing the hitch is easier than one would think, just put the TV in reverse and watch what happens to the trailer as the steering wheels are turned and the forces are reversed.
A more appropriate demonstration would occur if you grasped the top bar, (TV), in your left hand, and the bottom bar, (TT), in your right hand, and then, pulling outward with both hands, tried to turn the ends of either one in towards the other. If the geometry is correct, only the bar with the shortest distance between the pivot points will allow a "Turn" to occur.
On the hitch, suspended from the TV, this is simulated by grasping the weight distribution bars or the strut connecting pins, leaning back, and pulling less on one side than the other. On a true 4-bar, that you have demonstrated, this would result in a turn, but on the Hitch, it does not.
And in the interest of helping clarify the VPP concept, it is useful in explaining how the TT tracks behind the TV, and why the trailer backs up the way it does. It is also useful in explaining where the side loads are felt when the trailer attempts to shift its angle relative to the Tow vehicle because it represents one end of a lever.
Reversing the hitch is easier than one would think, just put the TV in reverse and watch what happens to the trailer as the steering wheels are turned and the forces are reversed.
