Stressor
Whitefish Bay, Wisconsin
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ttsr4us wrote:I have read this with great interest. I am a Hensley owner and it taimed my sway problem which my Reese Dual Cam was unable to do. I am reaching some understandind about how this hitch works but am not quite there yet. One problem I have is that I am able to move the hitch from the TT end when I insert a bar into the hitch to unlock the drop down bar which prevents the hitch from moving when disconnected from the trailer. I can rotate it around quite freely buy pushing into the TV direction and applying a rotating force at the same time. So is this a force direction issue, ie tension rather than compression which would also explain why the brakes on the trailer have to be set correctly? Sorry to stir the pot but I have not seen this aspect discussed. (I may have missed it)
If I read this correctly, you are actually moving the tow vehicle end when you are inserting a bar to move the lock out of the way. You have become the stinger and tow vehicle. It is not a force direction issue, it is strictly a linkage issue. The linkage is narrower at the TV end, and movement can occur due to simple leverage.
Milton Findley (and Kerene)
A small piece of my mind...
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Stressor
Whitefish Bay, Wisconsin
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tluxon wrote:ttsr4us wrote:...I can rotate it around quite freely buy pushing into the TV direction and applying a rotating force at the same time. So is this a force direction issue,...? Exactly! The force must be applied in a direction that complies with the tightly restricted elliptical-like path of the linkage in order to get it to move. Any other direction and/or combination will be met with incredible resistance, making many conclude that it is "locked" or rigid. It's not, but good luck ever getting a trailer to apply force and direction needed to pivot the hitch.
Brian, I believe you're the first Hensley owner to perceive the possibility of this behavior. You deserve some kind of award!
Tim
Tim,
Take the next 5 seconds and explain to us what you understand about come-a-longs, vehicle recovery straps, and willow trees.
The linkage is locked up from the travel trailer end, it moves freely from the TV end. See the pictures.
At what point does incredible resistance become locked up? In real life, 3/4 inch clevis pins do not bend. I have convincingly proven that there is no way to pivot the hitch from the travel trailer end without destroying hitch components, and had I kept on, I might have destroyed my TV hitch reciever, but the Hensley would not have pivoted, because it can't.
* This post was
edited 06/07/05 06:48am by Stressor *
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bettered
UpCountry SC
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Joined: 07/26/2004
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Stressor wrote:bettered wrote:ttsr4us:
I'm thinking you're pushing the head of the hitch in the direction of the TV and then TRANSLATING the black part of the hitch to the side. I suggest that you can't rotate it because of the linkage, but rather by translating it sideways, the linkage then forces the rotation. But of course with the TV attached, this is impossible, because you can't translate or rotate the hitch bar without moving the TV. And for those who haven't experienced this action, it's acheived with the hitch attached normally to the TT. The Orange part of the hitch is in this case immobile.
Ed B
This is true up until the linkage reaches 90 degrees, then it breaks over, see the link I posted after the pictures. The Hensley linkage only rotates about 160 degrees before running into itself.
All of the turns are through the linkage, and displacing the linkage changes the angular relationship between the truck and the travel trailer.
One more time, repeat after me, the hitch assemblies do not move relative to their attachment points on their respective vehicles. All movement occurs in the linkage.
Milt
Milt, the first three words were all you needed to say. A HA owner and Mechanical Engineer, I well understand the mechanics of linkages and the HA. Besides, I'm 5 years older than you..
Ed B
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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tluxon
Kirkland, WA
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I couldn't teach my 6-year old how to ride a bike without training wheels until HE himself wanted to learn. The best instructors in the world would be powerless to show you where your assumptions are faulty if you're convinced you already know everything he could teach.
I'm sure you're the only one in the world who's qualified to use a come-along, vehicle recovery strap, and willow trees. I hope I speak for everyone here when I say that it's very impressive that you knew how to set it all up. Too bad the clevis pin didn't cooperate better with your experiment.
Let me ask you this. When you set up your experiment, did you make any arrangements to LESSEN the friction between the tires of your tow vehicle (especially the front, but all four need to be ABLE to move) and the ground? Such as being at least at typical highway speeds or on a very slippery surface? How are you so sure that the reason your come-along couldn't "pivot" the hitch wasn't because no provision was given for the tow vehicle to ALLOW the front part of the hitch to translate with respect to the rear portion of the hitch? If you don't make that provision, all you've done is show that in your experiment you had sufficient traction to prevent the linkage from translating through its range of motion in response to the force imposed.
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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willald
NC
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Wow, this topic has gone a loooong time, and is great!
I am starting to get worried, though, that the 'disagreement' between the mechanical engineer (tluxon) and Hensley owner (Stressor) is about to make this thread get hateful. Please, lets not let that happen. This has been one of the best, most informative threads on the Hensley ever. Lets keep it that way.
Stressor made an EXCELLENT point, with the experiment with the hitch and strap to a tree. However, tluxon is correct, in that pulling on the hitch this way, does not allow the hitch to pivot through the elliptical path/virtuall pivot point, so it indeed would not move.
Anyway, I just sent an Email to Hensley, requesting that they have one of their engineer types, come on here and contribute to the thread. They probably won't do such, but I still thought I'd ask and see. ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
Will
* This post was
edited 06/07/05 08:55am by willald *
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tluxon
Kirkland, WA
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Will, you can rest assured that I harbor no ill feelings toward Milt, and will do my best to keep the thread on a helpful note.
Thank you for contacting Hensley. I myself will try to get a response from them as well, but understand any reluctance they might have to clearing up the "mysteries" of the hitch. There is a perceived "magic" about the hitch that they may prefer to leave that way. If they don't see how clearing this up can sell more hitches, I'd be surprised if anyone there would want to invest time explaining it in a public forum.
Tim
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bettered
UpCountry SC
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Wow Tim! You said a mouthful there. The "magic" of the hitch is probably why it demands the price Hensley gets. And that's true with everything that's for sale at 'high' prices in our society. As individual consumers, we have to decide when our need for something expensive (value) rises to the level of the seller's price. That's what keeps our economy percolating along...
Have you ever noticed how much stronger you value something before you buy it than after you own it? In the case of the HA, my sense is that most owners do not regret the price they paid for it - maybe more so when the road is slippery...
Hmmm.
Ed B
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Stressor
Whitefish Bay, Wisconsin
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I harbor no ill will either, but I know how to lock up a 4 bar linkage, and I know what the pictures prove. Now, if one of these worthy gents will simply describe how and why the linkage is locked it will save me the trouble. There is no magic, there is only mechanical stuff.
Note that the linkage will lock very readily on a table top, one does not need a truck, a travel trailer, or anything else, just a hitch sitting on the table.
Bettered, you have left the realm of engineering with your last post and entered into the realm of philosophy. Well done, we psychologists love that stuff.
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BurbMan
Indianapolis, IN
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Ed, The high price is not "magic"....it's function of an enforcable patent, and low volumes. In today's mass market, specialty trailer hitches is not a high-volume segment. Hensley hand-builds these things at their small local factory...if they could automate production in China, they could probably cut costs in half. Of course, they'll only get the attention of a Chinese mfr if they contract for large quantities.
Maybe Reese will bring out their own version when the patent expires??
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Ron Gratz
full time RVer
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Milt (a.k.a. stressor) has posted results from a "demonstration" which is intended to prove that an unrestrained rear unit (orange portion) of a HA will not move when subjected to a lateral force. The demonstration proves nothing of the sort, and it is misleading.
The demonstration is misleading because it ignores the fact that force is a vector. Force has both a MAGNITUDE and a DIRECTION. In this demonstration, the magnitude of the force is irrelevant, although it is presented as being of utmost importance. The direction of the force is of utmost importance, but it has been ignored.
Given that the objective of the demonstration was to show that the rear unit would not move when subjected to a force, it was very fortunate that the black willow tree was located where it was. This fortunate location meant that the POW-R-PULL force would be applied almost exactly in line with the right side link when the hitch was aligned straight ahead.
As Milt stated, "...the hitch will attempt to line up the linkage with the direction of the pull." However, there was no need for the rear unit to move appreciably because the right link already was lined up before the force was applied. If the tree had been a couple feet to the right or a couple feet to the left, the right link and the rear unit would have moved accordingly.
The demonstration also is misleading because the force is applied at the right strut pin location rather than at the ball or at the left strut pin location. Attaching the cable to either of these locations would have caused the rear unit to move to the right.
The post states, "This is intended to simulate a side load on the travel trailer end ..." If so, it is an extremely poor simulation. The images clearly show the cable to be nearly parallel to the longitudinal axis of the hitch and, therefore, the cable force would produce little or no side component. If Milt really had wanted to simulate a side load, he should have attached the cable to either the ball or the left strut pin.
There was no need to go to the trouble of rigging up the POW-R-PULL. It would only be necessary to push laterally by hand on the unrestrained rear unit to see how easily it moves side to side.
Although Milt's incomplete "demonstration" did not test the effect of the angle of the imposed force, it is easy to predict what would have happened:
1. If you pull on the rear unit with a force angled to the LEFT, the rear unit will move to the LEFT.
2. If you pull on the rear unit with a force angled to the RIGHT, the rear unit will move to the RIGHT.
3. And, if you are so lucky as to pull with a force at just the correct angle, the rear unit will not move at all. I guess Milt was just lucky.
Milt achieved nothing more than a result that a fortuitous (for him) and misleading (for the rest of us).
Ron
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