Stressor
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Joined May 29, 2001
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Re: Hensley Arrow: How does it REALLY work?
bettered wrote: Stressor wrote: The lateral force is applied to the whole rig under those conditions, because the Hensley linkage is locked up tight, and with the exception of whatever play there is in the components, the rig is as stiff as a two inch steel bar can be stiff. If you actually own a Hensley Arrow, you can demonstrate this to yourself on your next outing. Drive along and watch the rear end of your trailer for a while. Stop for a break, and while you are there, loosen the struts on the Hensley by a turn. Drive on, and watch the rear end of your trailer. You will see movement that was not there before. In a locked linkage, there is no virtual pivot point. Steering input from the tow vehicle unlocks it, and as soon as things straighten out, it is locked again. The trailer cannot exert a yaw force in a Hensley equipped rig. Check out the Hensley web site, they explain how the hitch "actually works" very clearly. :B The links between the upper and lower components of the hitch are fixed in place about their axis of rotation by double tapered roller bearings (both top and bottom) in the hitch, entirely similar to the way wheels are mounted on axles. If this system operates as you've suggested, why don't we have cars driving down the road suddenly "locking up" and skidding out of control to a panic stop. With millions of cars on the road, surely one of them would have experienced lockup by now. Bettered, you are another one who needs to buy a clue. :B1.7KViews0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
The lateral force is applied to the whole rig under those conditions, because the Hensley linkage is locked up tight, and with the exception of whatever play there is in the components, the rig is as stiff as a two inch steel bar can be stiff. If you actually own a Hensley Arrow, you can demonstrate this to yourself on your next outing. Drive along and watch the rear end of your trailer for a while. Stop for a break, and while you are there, loosen the struts on the Hensley by a turn. Drive on, and watch the rear end of your trailer. You will see movement that was not there before. In a locked linkage, there is no virtual pivot point. Steering input from the tow vehicle unlocks it, and as soon as things straighten out, it is locked again. The trailer cannot exert a yaw force in a Hensley equipped rig. Check out the Hensley web site, they explain how the hitch "actually works" very clearly. :B1.7KViews0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
Garfie|d wrote: 6MISFITZ wrote: Ron, On my thread, there was a story from what happened to Garfield in a corner with his trailer, so I do agree that the hitch won't save me from every law of physics or that of a ham fisted maneuver by the driver and that towing requires more attention - no matter what hitch. Gee, I think I was just insulted!!! LOL! ;););) (Kidding Mike!) :) Anyway, this thread extension appears to be focusing around an incident that I experienced last summer, so I thought I should clarify things, expecially because it underscores the need to ensure there's proper braking pressure to the trailer to control the Hensley even in situations where it may not be thought necessary. I experienced a situation last summer where I was slowly coasting into an intersection to make a 90 degree left turn. I was in a small town and there was no traffic around and I had the whole intersection to myself. I rolled into the intersection doing 10-15 kph and quickly cranked on the wheel without applying the brakes. After pulling a long trailer for a while you get into the habit of pulling well into the intersection and turn sharply, and that's what I did. What happend next I didn't foresee, although I should have. The short wheelbase Yukon turned very quickly as usual, but of course the trailer wanted to keep moving forward in a straight line, so it did. With no brakes to slow it down, it pushed against the Hensley which pivoted to the right and slammed against the stops with enough force to cause the rear wheels of my Yukon to lose traction and skid several feet towards the curb. As soon as I started sliding I instinctively hit the brakes which allowed the trailer to pull back on the Hensley and immediately halted the spin. If we were going much faster we easily could have jacknifed the whole rig. As I see it there were three major factors that attibuted to this incident: 1. I didn't apply (even lightly) the brakes to help control the trailer in a decelerating change-in-direction manouver. 2. The intersection was wet as it had recently started to rain. It had also been very recently paved and was covered in a mixture of oily water. 3. The short wheelbase of my Yukon worked against me as it turns VERY quickly. A longer WB vehicle wouldn't have been able to turn as quickly and might have prevented this incident. I consider myself a conservative driver (expecially when it comes to towing) but this incident really caught me by surprise because of the low speed involved. What I've learned from this is the need to apply the brakes in pretty well any decelerating speed manouver in order to ensure the Hensley is well behaved. It also convinced me that there is no way I will ever tow the trailer on snow or ice. I hope this helps to clarify things. This I believe. :B758Views0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
More nonsense. All you have to do is take your Hensley Arrow equipped rig out on a vacant stretch of road, and turn down the gain on the brake controller. Then brake while steering. Merely changing lanes while braking hard will do the trick. The tongue will move either left or right as the linkage collapses, the trailer will stay directly behind the tow vehicle for the simple reason that it can't go anywhere else under those conditions. And none ever have. :B The RGIH might work differently, but then, he don't sell many hitches.656Views0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
Ron Gratz wrote: TnAnFLA wrote: Ron, I think you've got it backwards. Andy, I'll accept that. That's why I said, "I think (but cannot prove)". This just demonstrates Milt's point that a person who does not own a HA should not comment about a HA. Whether the struts are in tension or compression will not change the fact that simply snugging up the struts does not result in any net forces acting on the HA's side links and front link. And if my recollection of physics is accurate (not a sure bet at all) the net force on the coupler/ball should be zero if both struts are of equal length. Both struts are "pushing" with equal force on opposite sides of the ball coupler. The struts are at an angle to the TT's longitudinal axis. If the right strut is in compression, it will exert a force to the rear and to the right on the right side of the A-frame. The left strut would exert a force to the rear and to the left on the left A-frame. The net lateral force between coupler and ball is zero. However, since both struts exert a rearward force on the A-frame, the coupler must exert a rearward force on the ball. Ron Ron, 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. Once again, an entity has been multiplied.244Views0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
tluxon wrote: Milt, if your proof is so good, why isn't anyone agreeing with it? As far as the "principle of parsimony", the whole idea of being simple is to also be complete. Your proof has been anything but complete. For one, you've failed to explain how Hensley was able to make a pivoting pin that had the intelligence built into that only allows movement if initiated from the front "bar" but not the rear "bar". Also, please explain why I've seen several Hensley owners comment that sometimes they see a slight wiggle from the TT but they couldn't feel it in the TV. Sounds like a great anti-sway device, but it sure doesn't sound like a "straight truck" to me. Tim Tim, You have failed to grasp the simple mechanical linkage that the Hensley Arrow represents. You are multiplying entities even as you write. It is totally predictable that if there is a slight wiggle from the TV, there will be a slight wiggle observed in the TT. The hitch is simply working as designed, according to simple mechanical principles. No scientist ignores data in favor of speculation. There are many many unsupported hypotheses here, none of which are demonstratable, falsifiable, and many of which ignore published information, and for that matter, video tape of the hitch in operation.246Views0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
All I am seeing is assertions without proofs, without any evidence, not even a photograph of a Hensley Arrow waving in the breeze, in an unlocked condition. Ron, there is no need to assume anything, we have hitches and hitches. Set up an experiment to prove or disprove your assertions. Remember: Occam's razor is also called the principle of parsimony. These days it is usually interpreted to mean something like "the simpler the explanation, the better" or "don't multiply hypotheses unnecessarily." William's Web site. AOHightech, your mechanical reasoning skills are certainly far more advanced than my own. I stand in your shadow.146Views0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
Ah, down to the two multipliers of entities without end. :B The liberal scientific method requires us to accept the simplest possible explanation that covers all the bases. The ghost of Sir William of Occam stands guard with a cudgel in hand for those who would violate this principle. Tluxon, Science does not care for legalese. I believe that the hitch projects the pivot point, as indeed it must in order for the linkage to lock up. I believe that this does in fact limit sway, and therefore the document is technically correct. How it does it seems to be missing from the patent application as it frequently is, and Hensley has recently granted us access to this information, illustrating it liberally, and telling us exactly how it does it. It is now up to us to accept it or come up with a better idea. I accept it. Ron, I do know the answer, and you are right, I am not telling. I am not telling because it has no bearing on how the Hensley works. There are no forces acting on the hitch that are not applied straight line through the struts. The hitch pivots left and right freely from the TV end, and not at all from the TT end. Moving the cable left or right means nothing because in operation there exists no mechanism for such a force to be applied. You have violated scientific method by positing something that does not exist and demanding an explanation of what would happen if it did. As an engineer, it should not be difficult for you to visualize the answer. If the force vector is straight back, and the hitch is locked up, moving the vector left or right would translate some of the force into a twisting moment while the remainder would still be pulling straight back. This has nothing to do with why the hitch is locked up, because that is a function of three pivot points being aligned, two made of steel and one virtual. Hensley appropriately calls this a converging linkage. The hitch ball is another red herring. I believe what Hensley says about its function, in that it is allowed to rotate and to pivot up and down to some extent, limited by the struts, and not at all side to side, prevented by properly adjusted struts. The pattern of wear on mine indicates that this is what is happening, and the movement allowed is demonstratable by using adjusting the weight distribution jacks separately, or in concert, to position the hitch head. Owners of the hitch know the principles of operation of the weight distribution jacks well, because this is what allows us to hitch up if the TV is tilted or off plane in relation to the TT. You might also note that most of us recommend that the purchaser also buy a Tongue Twister. The reason for this is that the hitch head moves not at all side to side. One more thing needs to be said. This thread is about the Hensley Arrow hitch and how it works. It is well known, and accepted almost universally, that the Hensley Arrow prevents sway. It makes sense to discuss the hitch alone because the hitch is the only difference between a trailer that can sway and a trailer that cannot. It makes no sense at all to make statements to the effect that the Hensley Arrow prevents sway by working in concert with numerous items that existed before the Hensley was installed. If the only difference in the equation is the Hensley, it is the Hensley that makes the difference.377Views0likes0CommentsRe: Hensley Arrow: How does it REALLY work?
AO_hitech wrote: Stressor wrote: This picture proves, real world, inarguably, that the Hensley hitch locks up from the travel trailer end. Okay, I'm new here. I can't see how that picture shows anything. If I do the same thing to a standard WD hitch and connect the come-along to where the WD bars attach I'll get the same results. So, how is that showing the HA locks up from the TT perspective? AO, Thanks for posting that wonderfully instructional picture. The cable is not attached at the same point as the weight distribution bars, those are what is flapping in the breeze out to the sides in the picture. Go here if you will, and read what it says. You will be caught up in no time flat, the Hensley is really a simple device and virtually foolproof.375Views0likes0Comments
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