tluxon
Kirkland, WA
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From a few posts back:Stressor wrote:Whatever Tim, the fact is that the links are at 90 degrees to the hitch bar when the angular difference between the Tow vehicle and travel trailer is approximatly 30 degrees.
I have a Hensley Arrow Hitch, and I looked and I measured. Are you talking about the side links? Or one side link and one end bar? When I ran the sketch which is based on the Hensley patent dimensions through all the possible angles, there was no point at which both side links were at 90 degrees to the hitch bar. Perhaps your hitch is a special edition that wasn't addressed in the patent? In that case, I'll just have to take your word for it, but it doesn't make any sense.
Stressor wrote:...In operation the rear of the travel trailer moves very little, until the steering wheel is turned...
...it does not translate at all during straight ahead pulling. So when you hit the brakes on a slight downgrade at a stop sign on a curve, you won't see any translation that's not initiated by the TV? Other HA owners have commented on a type of surging under such conditions that's indicative to me of a translation. If I remember right, I believe it's even been aluded to at least once in this thread.
Stressor wrote:A TV camera would be nice, but Hensley did that already and it shows a lot of translation as the tow vehicle travels in and around a series of pylons. I can post a link to a short clip of that part of the Hensley video that may be helpful to readers of this thread. Should I put it up?
BTW, I think you're being a little unfair to Ron - perhaps because he wasn't in agreement with you. Sometimes we say things that can be interpreted in more than one way and we're misunderstood, and I think this is what happened with what Ron was saying. The way I interpret it, he was saying that because the ball was securely attached to the rear bar, that when the rear bar translated it brought the ball with it. I'm positive he was referring to when the angle between the vehicles was changing. I also think his numbers regarding how much the rear bar and ball translated with respect to the original centerline upon turning were very close.
Tim
Tim -
wife Beverly & 2 boys who love camping
2002 K2500 Suburban 8.1L 4.10 Prodigy
2005 Sunnybrook 30FKS HP Dual Cam
Replaced 2000 Sunnybrook 26FK on 8/6/04
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Ron Gratz
full time RVer
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Stressor wrote:
I don't know where Ron gets his stuff, and last time we talked, he was still swearing that the upper orange hitch assembly pivoted on the ball.
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/biggrin.gif "biggrin")
Once again Milt is having trouble separating fact (see below) from fiction (see above). I guess Milt believes that, if you misrepresent the truth to enough people enough times, some of them will begin to belive you. Or, perhaps Milt can show where I have made such a statement and I will owe him an apology.
Ron
Posted: 05/23/05 05:45pm Link | Quote | Print | Notify Moderator
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Stressor wrote:
...Let us not trivialize or ignore the statements made. The orange head of the Hensley does not move, relative to the trailer tongue, period. ...
Milt, I'm afraid other members are going to think you do not read my posts before responding to them. I have never said that the orange portion moves relative to the trailer tongue. In fact, I have said that the tongue is rigidly connected to the orange head via the struts and the ball coupler.
Ron
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tluxon
Kirkland, WA
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Milt, you asked this of Ed:
Stressor wrote:You have not addressed the lack of translation in the hitch picture. The application of a very large off center rotational force from the travel trailer end of the linkage has not resulted in any rotation, translation, or what have you. What is your explanation for this? You say it is not locked up, can you explain the lack of movement?
I thought Ron provided a pretty good explanation for why there was no translation in response to the force you applied.
I'd like to add to this. It has to do with the direction from which the force was applied. In order to get translation, you would have to apply a force tangent to the path made possible by the linkage, which is elliptical. This would be almost 90 degrees from the direction of force you applied, so I'm not at all surprised that you didn't see any translation in that direction. It would be very hard to spin a bicycle wheel by pulling on one of the spokes.
Follow?
Tim
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Stressor
Whitefish Bay, Wisconsin
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Whatever. That was a direct quote by you Ron, in your PM to me. You really do not know how the hitch works, despite the precision of your measurements.
Bye.
Milton Findley (and Kerene)
A small piece of my mind...
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tluxon
Kirkland, WA
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Stressor wrote:Whatever. That was a direct quote by you Ron, in your PM to me. You really do not know how the hitch works, despite the precision of your measurements. People often say things that are interpreted to be incorrect, but the full body of their work makes it easy to see that they don't believe what you first concluded they did.
In this case you don't even have to work that hard. Unless I'm missing something, Ron clearly stated that he doesn't believe the trailer coupler moves with respect to the rear bar of the HA linkage, yet you hold firmly to your first interpretation that he does. I'm sorry but I just don't get it.
I happen to think Ron has a very good understanding of how the hitch works, and I believe many readers of this thread feel the same. Just because you don't agree with him doesn't automatically make him wrong. Or maybe that's the only way it CAN be? Hmmmmmmm.
Hang in there, Milt. I believe if we keep plugging away at this thing we'll find more common ground.
Tim
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willald
NC
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Let me see if I can make an attempt, to 'combine' the two different schools of thought here, into something we can all agree on:
Milt (Stressor) argues that the 4 bar linkage, in actual, practical use on the Hensley, basically prevents any pivoting AT ALL from the trailer's perspective, and from the trailer's standpoint, everything is locked in line, like a straight truck. Based on how us Hensley owners have observed our rigs behave, its very easy to believe this.
Tim (tluxon) argues (and has lots of fact to support such) that there IS indeed pivoting that can take place from both ends (tow vehicle or trailer), but it MUST pivot through the 'projected' virtual pivot point/elliptical path, that we have outlined/discussed in great (and fascinating!) detail.
Perhaps BOTH of you are right, to a certain extent:
I would submit, that Tim is right in that pivoting does take place from both ends. However, due to the way the pivot point is projected, it is VERY difficult (almost impossible) for the trailer to initiate much pivoting at all through that pivot point/elliptical path.
So in essence, from the trailer's perspective, it cannot pivot. Or, the pivoting it DOES do, since it pivots through the virtual pivot point/elliptical path we have outlined, is pivoting that does not affect the tow vehicle at all, so it basically eliminates all swaying as we know it.
How does this sound? Can we all agree on this? Or, am I over-simplifying it too much? ![[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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Stressor wrote:Ed,
Mr. Gratz does not understand the linkage. I have read his remarks for some time, and his understanding of the hitch is imperfect. Some of it he has down very well, but he is unable to visualize the operation in use. He still thinks the hitch pivots on the ball.
Here is a quote from him:
,..." The rear link, which actually is the upper (rear) housing, does move side to side and the ball is securely attached to it. When the rear link moves, the ball also must move. It makes no difference whether the ball moves about 5" to one side or moves precisely 4.768" to one side. The point is – the ball does move side to side. The figure of 4.768" derives from the assumption that the front pins are 7.125" center to center, the rear pins are 7.875" center to center, and it is 5.000" center to center from a front pin to a rear pin. If you prefer to use different numbers and different tolerances, I can provide the corresponding maximum side to side movement."
This statement can only be true if the rear struts are very, very loose.
My apologies to all who are tired of reading my rebuttals to half truths and untruths.
Yes, Milt, that is a direct quote from a PM I sent you. The statement is true even if the struts are very, very tight.
Can you please tell all of us where I stated that the hitch pivots on the ball? Can you please point out where I even mentioned the words "hitch" or "pivot"?
Ron
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bettered
UpCountry SC
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"Cannot" is a pretty strong way to put it. One specific situation -- downhill entering a curve particularly if slippery or with a faulty brake controller is a hazardous condition for the Hensley. The same situation would be hazardous for any other hitch, only more so.
The hockey puck scenario is interesting but somewhat unrealistic to the extent that each wheel in a typical TT is seeing about a ton of weight. That times any nominal friction coefficient yields at least 100# of friction (per wheel) to resist any reactions at the hitch. As we have seen in the calculations, the actual disruptive loads are probably going to be less than this.
As long as the TV itself is not sliding or until it starts to lose traction, whether aggravated by the TT or not, the TT will remain under control of the TV. I would not want to trust my life or my rig to any other arrangement.
Beyond that, I'm in substantial agreement with Will.
BetterEd
DW + 2 grandkids + Mini Schnauzer
2005 Chev 3500 Crew D/A 6.6L LLY, 6 x 6 DRW, 3.73
Tru-Flow + Banks, 2005 Flagstaff 831FKSS
Hensley + Prodigy
"Genius may have its limitations...." E. Hubbard 1856 - 1915
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willald
NC
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Alright, betterEd, let me try to refine the summarization somewhat:
Perhaps BOTH of you are right, to a certain extent:
I would submit, that Tim is right in that pivoting does take place from both ends. However, due to the way the pivot point is projected, it is VERY difficult (almost impossible) for the trailer to initiate much pivoting at all through that pivot point/elliptical path.
So from the trailer's perspective, it essentially canot pivot except in extreme circumstances. Or, the pivoting it DOES do, since it pivots through the virtual pivot point/elliptical path we have outlined, is pivoting that does not affect the tow vehicle at all, so it basically eliminates all swaying as we know it.
'Extreme circumstances' above, refers to situations where the brake controller is not adjusted right and heavy braking is done, such that the trailer is 'pushing' the tow vehicle more than it should. This situation would be made worse, if it happened when curving. (Which is why, even with a Hensley hitch, you still have to make sure the rest of your rig is set up correctly).
Can we all agree on this?
Will
Will and Cheryl
2021 Newmar Baystar 3014 on F53 (7.3 V8) Chassis ("Brook")
2018 Jeep Wrangler JK ("Wilbur")
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2lMan
Brewer, ME
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I can agree on this...
These actions, make the trailer/tv connection, "virtually solid" when looked at from the TT end, as in acting on the tow vehicle.
It theoretically can move, but would require huge, HUGE forces to do so.
Works for me...
Craig
2003 GMC Yukon XL 2500 8.1L 4.10 Axle - 2002 Sprinter Quad Bunkhouse
Home is where you bring it!
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