Ron Gratz
full time RVer
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Joined: 12/27/2003
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Will,
Why do you feel that the HA's ability to reduce the magnitude of lateral loads combined with its ability to move the pivot point closer to the TV's rear axle is not a sufficient explanation of its anti-sway capabilities?
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smthbros
WI
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Joined: 02/15/2004
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Ron,
Thanks for taking time to explain how the Hensley works. I made a model out of sheet metal strips. It appears to me that in order for the front of a trailer (with a HA) to move sideways the motion of the rear of the TV is in the opposite direction. Might this be a third reason for why the HA works?
J Smith
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willald
NC
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Ron Gratz wrote:Why do you feel that the HA's ability to reduce the magnitude of lateral loads combined with its ability to move the pivot point closer to the TV's rear axle is not a sufficient explanation of its anti-sway capabilities?
Well, that depends on how/why you believe the Hensley 'reduces the magnitude of lateral loads'. Perhaps you already hashed that out earlier in this thread and I glossed over it. If so, I apologize.
If you include in there that the reason it reduces that lateral load, is because of the 'locking' the Hensley does (on trailer side) when being pulled, then yes, I would agree, that this is a sufficient explanation.
However, I do not feel that strictly the Hensley's ability to move the pivot point forward 47" is enough of an explanation, to explain what I and others have experienced towing with it. If that was truly all it was doing, I firmly believe our towing experience would not be quite as good as it is now, with the Hensley. Perhaps there is another explanation, but I don't know what it might be. That was why I started this thread, to try and find that explanation. ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/biggrin.gif "biggrin")
Will
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BurbMan
Indianapolis, IN
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Joined: 09/20/2001
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Ron, nobody is discounting or disputing the value of the analyses you put forth on this subject. You've been able to quantify the physics and geometry of the HA equation very clearly, if not a bit complicated for your average marketing guy
I'll go out on a limb and say that both Will and I agree with everything you have said to this point. However, what we are saying is that in addition to all that, the tension that exists between TV and TT as the TT is being towed adds additional resistance to ANY movement of the 4-bar linkage, particularly inputs from the TT.
Can you formulate a proof that shows that these forces do not affect the behavior of the HA? I think that would effectively let the air out of our tires.
Don
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willald
NC
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BurbMan wrote:Ron, nobody is discounting or disputing the value of the analyses you put forth on this subject. You've been able to quantify the physics and geometry of the HA equation very clearly, if not a bit complicated for your average marketing guy
I'll go out on a limb and say that both Will and I agree with everything you have said to this point. However, what we are saying is that in addition to all that, the tension that exists between TV and TT as the TT is being towed adds additional resistance to ANY movement of the 4-bar linkage, particularly inputs from the TT.
Can you formulate a proof that shows that these forces do not affect the behavior of the HA? I think that would effectively let the air out of our tires.
I agree with Don 100% here. We agree with everything you've said, Ron, and all of your analysis. We just think (based on what we've personally experienced, and seeing how the Hensley pivots) that there is a bit more to it that is being overlooked, thats all.
That 'more to it' is that when the Hensley is under tension/pulling, it really appears that this effectively locks the trailer, and prohibits it from inducing any pivoting. When that 'pulling' affect goes away, then all your analysis/diagrams indicating how the Hensley allows pivoting, are right on.
As far as Ron proving these affects do not change behavior, that'd be just about as difficult, as us PROVING these affects DO change behavior. LOL! Either way, one of us is going to have to build this 'model' we've talked about, and see what happens. ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
Will
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Ron Gratz
full time RVer
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Joined: 12/27/2003
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smthbros wrote:Ron,
Thanks for taking time to explain how the Hensley works. I made a model out of sheet metal strips. It appears to me that in order for the front of a trailer (with a HA) to move sideways the motion of the rear of the TV is in the opposite direction. Might this be a third reason for why the HA works?
J Smith
J,
The model I've constructed has a "front link" which is 7 1/8", two "side links" which are 5", and a "rear link" which is 7 7/8". I put the front link in a vise to simulate the fixity of the rear of the TV and then observe how the other three links move. Since I don't know how your test was conducted, it's hard to comment on what you observed.
However, let's assume you're observing a northbound TT which, for whatever reason, has swung toward the east. If you are standing at the front of the TT, the rear of the TV will appear to have moved to the west. If you're standing at the rear of the TV, the TT will appear to have moved to the east. And, if you are standing at a point in between the front of the TT and the rear of the TV, the TT will appear to move east while the TV appears to move west. This will happen with any kind of hitch system. I don't think it's a special characteristic of the HA.
Ron
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Ron Gratz
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willald wrote:Well, that depends on how/why you believe the Hensley 'reduces the magnitude of lateral loads'. Perhaps you already hashed that out earlier in this thread and I glossed over it. If so, I apologize.
Will,
I am deeply distressed to read that you might have glossed over one of my spurious explanations. I even gave the post a bold font title, How the HA Reduces Lateral Loads Imposed by TT on TV so you would be sure to read it. Well, anyway, apology accepted.
Quote:If you include in there that the reason it reduces that lateral load, is because of the 'locking' the Hensley does (on trailer side) when being pulled, then yes, I would agree, that this is a sufficient explanation.
No, I did not include that effect because it does not exist. The HA doesn't need it.
Quote:However, I do not feel that strictly the Hensley's ability to move the pivot point forward 47" is enough of an explanation, to explain what I and others have experienced towing with it. If that was truly all it was doing, I firmly believe our towing experience would not be quite as good as it is now, with the Hensley. Perhaps there is another explanation, but I don't know what it might be. That was why I started this thread, to try and find that explanation.
There does not need to be another explanation. Sufficient explanation is given here. That amount of reduction is all you need to get the effect that you and others have experienced.
Ron
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Stressor
Whitefish Bay, Wisconsin
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Joined: 05/29/2001
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Ron Gratz wrote:
No, I did not include that effect because it does not exist. The HA doesn't need it.
![[image]](http://home.ripway.com/2005-1/238631/Folder%20Name/Hensleytext006.JPG)
This photograph proves that the locking effect does exist. Rocker/Rocker 4 bar linkage theory predicts the lock.
Despite your long winded, and spurious remarks previously, changing the angle of the pull does not change the fact that it is locked.
The hitch locks to input from the travel trailer side, and anybody who has one can easily prove it to himself, by simple duplication of the set up pictured.
Milton Findley (and Kerene)
A small piece of my mind...
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willald
NC
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Hmmm...Looking at Milt's picture, I'm trying to visualize another model we could build, that will prove the point about locking (when Hensley is under tension), and prove it beyond reproach by even someone like Ron.
What if we were to somehow mount the drawbar on something solid, like maybe a workbench? Basically, mount the drawbar pointing down, and mount it on something REALLY solid. Mount it, such that it could handle a lot of weight.
Then, attach the Hensley hitch to the drawbar (all pointing down). We'd then have to build a 'model' A frame of a trailer, perhaps with 3 pieces of 2x4 wood, and mount this to the Hensley, the same way it normally mounts to the trailer A frame (using the struts). Now, we just have to mount something really heavy to the bottom of the wood A frame we built, so that it pulls down real hard on the Hensley. For this example, lets say we mounted, an anvil (lol).
NOW, after we have this, try pushing the wooden A frame side to side. You will find, that in order to make it pivot, you'd have to overcome a LOT of resistance, because you'd literally be lifting the weight of the anvil in order to make it pivot, since the Hensley's pivot path forces the Hensley to move forward (up in this case) as it swings away from a straight line. The path through which it would pivot (making you lift the anvil) would NOT be the same as a simple pendulum with respect to the Hensley's Virtual pivot point, as Ron would suggest. It would be more like a pendulum where the arm shortens as it swings to either side.
Make sense? Who wants to volunteer to build this?
Will
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Ron Gratz
full time RVer
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Stressor wrote:This photograph proves that the locking effect does exist.
Milt,
For the test condition depicted in your photo, what was the horizontal angle between the cable and the TV's longitudinal axis?
Quote:Rocker/Rocker 4 bar linkage theory predicts the lock.
Can you provide a link to a reference which supports this statement?
Quote:Despite your long winded, and spurious remarks previously, changing the angle of the pull does not change the fact that it is locked.
Did you change the angle of the pull?
Did you pull, say, 10 degrees to the left and 10 degrees to the right of the angle shown?
Do you have photos to show the cable pulling at other angles?
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