Ron Gratz
full time RVer
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Joined: 12/27/2003
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drfife wrote:Ron, actually the struts are static if the hitch is not towing.
The struts can be in tension or compression while towing depending on the direction of the applied forces.
The struts are nothing more than fixed length rods.
Yes, you snug them up during installation, but they should not be forced into compression.
Stressor wrote:--- I meant to tell you, the struts can only be in compression, either less or more compression. There is absolutely no way to put one in tension, as it is a two part assembly, and simply falls apart.
When they are installed and correctly adjusted, they are in considerable compression.
They could be welded in place and it would make no difference in the operation of the hitch.
Russell,
I'll let you Hensley owners sort this one out. As I said earlier, it doesn't make any difference if they are in tension or compression as long as they prevent the coupler from pivoting (yaw) on the ball.
Ron
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TnAnFLA
Nokomis FL
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Joined: 02/18/2005
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drfife wrote:The struts can be in tension or compression while towing depending on the direction of the applied forces.
Actually, you'd best hope they stay in compression while towing. When you snug them up, tightening the nut places them in compression. Ideally not a lot, but definitely in compression. If the forces on the TT are enough to take them out of compression, it would have the same effect as loosening up the lock nut to the point that the struts are no longer snug, and then the coupler is free to rotate on the ball on the upper unit of the Hensley. And if it got too loose, all bets are off on effective sway control, since you've added yet another pivot point.
Andy
31' Itasca Impulse
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BurbMan
Indianapolis, IN
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Joined: 09/20/2001
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bettered
UpCountry SC
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Joined: 07/26/2004
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TnAnFLA wrote:drfife wrote:The struts can be in tension or compression while towing depending on the direction of the applied forces.
Actually, you'd best hope they stay in compression while towing. When you snug them up, tightening the nut places them in compression. Ideally not a lot, but definitely in compression. If the forces on the TT are enough to take them out of compression, it would have the same effect as loosening up the lock nut to the point that the struts are no longer snug, and then the coupler is free to rotate on the ball on the upper unit of the Hensley. And if it got too loose, all bets are off on effective sway control, since you've added yet another pivot point.
Andy
They COULD be in tension or compression and still work by restraining the head - as Ron says, but the choice is altogether design dependent. As now designed, they cannot be in tension - as Andy says. They would come apart. So they are in compression only to the extent that the strut on one side pushes across the ball (pivot) and put an equal compressive force on the other. The force does not want to be so great as to cause a bind, merely to (as Ron says) to prevent rotation about the ball in yaw. I think their only function is to force the yaw movement into the linkage while allowing roll and pitch movements about the ball when going over uneven ground.
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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Trail-Mate
Frederick, MD
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Joined: 01/22/2004
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You guys have done a great job of analyzing this Hitch. Hensley had a display setup at the Hershey Show. I watched the person display and describe the hitches operation. The displayer stated the the hitches links that form the trapaziod. He then said to draw a line from the links forward they will intersect at 5 1/2 feet forward. So acording to him the pivot point is now there. So from the trailers perspective it can't cause motion on the TV because the pivot point location is not actually a pivot point so its locked. The TV can turn the hitch because that virtual pivot point does not exhist looking back from the TV. That is they way it was explined at the Show. They had the model that they show in the video in the booth. I also got a free hat.
1997 Ford F250 Extended Cab, 7.3 Diesel, 8 foot bed.
Reese 16K Hitch
(Moved into Shed) Hensley Arrow
Jordan Brake Controller, Hensley TruControl Gold Shelved.
Open Range 5th Wheel, Roamer RF392 BHS
Happy Camping !!
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willald
NC
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Trail-Mate wrote:You guys have done a great job of analyzing this Hitch. Hensley had a display setup at the Hershey Show. I watched the person display and describe the hitches operation. The displayer stated the the hitches links that form the trapaziod. He then said to draw a line from the links forward they will intersect at 5 1/2 feet forward. So acording to him the pivot point is now there. So from the trailers perspective it can't cause motion on the TV because the pivot point location is not actually a pivot point so its locked. The TV can turn the hitch because that virtual pivot point does not exhist looking back from the TV. That is they way it was explined at the Show. They had the model that they show in the video in the booth. I also got a free hat.
Would have been very entertaining, if Ron, Tim, Don & I could have been at that display, and had a discussion with the displayer there. ![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
His initial point about the two sides intersecting at 5 1/2 feet, may or may not be 100% accurate. I measured the sides on my Hensley, and as you'll see early in this thread, we used these measurements, and came up with a figure of about 47" forward (about 4 feet). Not sure which is more accurate (4 or 5 1/2), but we'll leave that minor detail alone for now.
Still, his ascertion that the pivot point is 'not there', confuses me. If the trailer pivots, it DOES pivot through this virtual pivot point as we called it, so I don't understand why he says the point is not there. Sounds like a little marketing gibberish and double-talk going on there. Granted, we have established that for several reasons its nearly impossible for the trailer to induce any pivoting, but we won't go down that path again.
Anyway, like I said, sure would have been entertaining, if those of us that had this loooong, detailed discussion about the Hensley, could have discussed it with the displayer you saw at the show there.
Will
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Trail-Mate
Frederick, MD
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I'm just passing on what was said by the displayer. I may have the number off some I though he said 5 1/2 feet but it might have been 5. I'm sure he did not say 4. Like I said. You guys have done a great job.
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willald
NC
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Trail-Mate wrote:I'm just passing on what was said by the displayer. I may have the number off some I though he said 5 1/2 feet but it might have been 5. I'm sure he did not say 4.
Right, I understand that you were just passing on what you saw/heard. Appreciate you doing that, it is interesting to hear that Hensley's projected pivot point is 5 1/2 feet forward, we estimated it at more like 4 feet forward. Becomes a question of, did we mis-measure or miscalculate somehow, or did Hensley stretch the truth a bit, for marketing? Perhaps a little of both.
Quote:Like I said. You guys have done a great job.
Yeah, there was some great discussion here. We have some really, really smart people in these forums. I think this thread was proof of that.
Will
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BurbMan
Indianapolis, IN
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Will I think when he said "it's not actaully a pivot point, it's locked" he was referring to the trailer coupler/ball and not the VPP.
Almost all of us agree that the trailer is locked from rotating by the Hensley Hitch. Let's re-open that can of worms....![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/rolleyes.gif "rolleyes")
Milt, are you with me?
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Ron Gratz
full time RVer
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Joined: 12/27/2003
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willald wrote:--- it is interesting to hear that Hensley's projected pivot point is 5 1/2 feet forward, we estimated it at more like 4 feet forward. Becomes a question of, did we mis-measure or miscalculate somehow, or did Hensley stretch the truth a bit, for marketing? Perhaps a little of both.
Will,
If you or another HA owner could get Hensley Mfg. to divulge the exact center-center spacings for the linkage pins, we could settle the question of how far the pivot point is projected forward. In the straight-ahead towing configuration, it is a matter of simple trigonometry to determine the point at which the side links would converge.
The Hensley patent document gives the following C-C spacings for the linkage pins:
Left front to right front = 7.125"
Left front to left rear = 4.5"
Right front to right rear = 4.5"
Left rear to right rear = 7.875"
Other Hensley information suggests that the front to rear spacings are 5.0" Sure would be nice to know what Hensley says the values are.
Ron
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