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Old 09-07-2012, 09:54 AM   #421
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Originally Posted by purman View Post

Mstephens: if you read the whole thread then I don't see why you would have any questions as to it working? IT DOES.

I haven't put mine on the scales (but plenty have and the numbers are out there) but when my tire to wheel well measurements are within a 1/4 or original, I know it is distribution weight.. END OF DISCUSSION.
Purman: I did read the whole thread. And, I did not see any mechanical analysis of the hitch aside from T. Andrews "back of the napkin" calculations. I saw a lot of claims and some argument about the claims. That is why I still have questions. It's an interesting idea, but has a rather unorthodox means of WD.

If you enjoy horsewhipping me for being curious about the physics, go ahead, I have a thick skin and don't mind.
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Old 09-07-2012, 10:15 AM   #422
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Purman: I did read the whole thread. And, I did not see any mechanical analysis of the hitch aside from T. Andrews "back of the napkin" calculations. I saw a lot of claims and some argument about the claims. That is why I still have questions. It's an interesting idea, but has a rather unorthodox means of WD.

If you enjoy horsewhipping me for being curious about the physics, go ahead, I have a thick skin and don't mind.
In defense of mstephens, he is asking questions and trying to find explanations for why the hitch works, not saying that it doesn't. It is going to help a lot more to discuss how the design works than to put someone down for questioning it. The answers should be available from the manufacturers. I too am curious about the forces on the chain. Assuredly, this hitch must have been engineered and that data should be available.

So, for those who are using this hitch, who I assume are wanting others to use it, I might suggest that less sensitivity toward questions and more helpful answers would better serve expanding the user base.

Ken
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Old 09-07-2012, 10:21 AM   #423
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In defense of mstephens, he is asking questions and trying to find explanations for why the hitch works, not saying that it doesn't. It is going to help a lot more to discuss how the design works than to put someone down for questioning it. The answers should be available from the manufacturers. I too am curious about the forces on the chain. Assuredly, this hitch must have been engineered and that data should be available.

So, for those who are using this hitch, who I assume are wanting others to use it, I might suggest that less sensitivity toward questions and more helpful answers would better serve expanding the user base.

Ken

Hear, hear! me too, x3 on the WD physics. I too scratch my head on the tension required with the small angle and distance from the chain attachment point to the ball relative to leverage.

I TOO AM NOT SAYING IT DON'T WORK.....I'm having trouble reconciling the physics is all.
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Old 09-07-2012, 10:33 AM   #424
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Take the 34' & Excursion example. To push the front axle of an Excursion down 1/4" requires about 200 pounds of weight. The front axle is just over 16' from the ball that means the hitch needs to exert 3200 pounds of torque on the reciever to transfer that weight. Likely 400 pounds is being transfered to the excursion's rear axle 5' away so that will take another 2000 pounds of torque for a total of 5200 ft pounds of torque on the receiver.

The equation is not as simple as this. Weight is not transferred to the rear axle it is removed from the rear axle with the help of the TV rear springs and the WD hitch. If you remove weight from the rear axle you by lifting the rear of the TV you will add weight to the front axle. I have the 34 ft Airstream and the Excursion.

One other element is that this hitch will always transfer weight in the direction the trailer is pointing. A conventional weight distribution hitch set up properly will always transfer weight to the front wheels of the tow vehicle instead of the outside rear wheel in a turn.

Now think about this for a minute. Move a Reese or Draw Tight system to one side and apple upward force on the bars. Those bars will produce a torque force to rotate the receiver and reduce some of the force transferred to the front axle. Yes this will happen with any hitch but it is not a significant force when compared to the natural roll to the outside, effected by speed, of a vehicle turning.

I have stated before that I spent a night sleeping on this one before i bought it. Yes I had to dig deep back into my mechanical classes to finally figure out how the ball /coupling acted in the system. Woke up the next day and placed my order.

Yes the hitch works on my 34/Excursion. What many have missed is the fact that it not only works for WD but eliminates porpoising. Now for those that will question that let me say the ring out of a mechanical system using urethane as a spring is much less than that of a steel spring system. That is way they use urethane mounts for equipment rather than steel springs.

Any system that produces desirable a secondary effect and cost significantly than the competition warrants consideration.
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Old 09-07-2012, 10:53 AM   #425
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For those that may question my support of this system in light of the fact that I have posted what I see as modifications to the system let me say this. I have modified every WD hitch I have owned or installed them on a trailer the manufacture claimed could not be done. In each case I have advised the manufacture of the problem that warranted the modification. There responses I assume are based on cost analyses by there accounts and advice from there lawyers. I doubt the engineers are ever brought into the question. Had then been the problem may not have existed in the first place.
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Old 09-07-2012, 10:55 AM   #426
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Originally Posted by mstephens View Post
Purman: I did read the whole thread. And, I did not see any mechanical analysis of the hitch aside from T. Andrews "back of the napkin" calculations. I saw a lot of claims and some argument about the claims. That is why I still have questions. It's an interesting idea, but has a rather unorthodox means of WD.

If you enjoy horsewhipping me for being curious about the physics, go ahead, I have a thick skin and don't mind.
No Horsewhipping here, sorry. It just gets old when the same concerns are brought up over and over again, and addressed over and over again, over 31 pages. It's not like people go to the Hensley or ProPride thread and say; "this can't work, I don't believe you that it works, I want to see the physics, and then expect none engineers to come up with them"

If you wanted just the physics of it, why not ask that directly? You didn't in your original post. Best why to get them is to call Andersen. They are always willing to talk to anyone who calls.

Funny thing is: the physics are basically (not exactly) the same. It puts torque on the bottom of the the ball, twists it, and pushes down on the front, distributing weight. Just because it does it by pulling more than lifting doesn't mean it doesn't get the job done...



I encourage you to call Andersen. I'm sure they would be glad to talk you through the physics of it, if this is your biggest concern. Many of us here have called them and they are glad to talk to anyone.

Then like the rest of us, you will want to buy one, and never go back
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Old 09-07-2012, 11:06 AM   #427
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"It just gets old when the same concerns are brought up over and over again, and addressed over and over again, over 31 pages."
===
But realize that the "over and over" is just verbal claims and counter claims, not physics and math. What I was in search of is the simple force diagram of the hitch. So, even though you see it as over and over, I haven't even seen it yet as ONCE!
But no offense taken. Like I said, I have a very thick skin.

I'll draw out a force diagram based on guesstimates of the distance of the chain plate from the receiver. See if I can make it work out.
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Old 09-07-2012, 11:14 AM   #428
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Originally Posted by mstephens View Post
"It just gets old when the same concerns are brought up over and over again, and addressed over and over again, over 31 pages."
===
But realize that the "over and over" is just verbal claims and counter claims, not physics and math. What I was in search of is the simple force diagram of the hitch. So, even though you see it as over and over, I haven't even seen it yet as ONCE!
But no offense taken. Like I said, I have a very thick skin.

I'll draw out a force diagram based on guesstimates of the distance of the chain plate from the receiver. See if I can make it work out.
You didn't ask for one..
I would still call Andersen, I'm sure they can supply you with one..
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Old 09-07-2012, 11:30 AM   #429
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This is getting like those commercials "I'm 99.999 percent sure; than your not positive" or "Try it, you'll like it!"
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Old 09-07-2012, 12:16 PM   #430
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It transfers weight and reduces sway. Unlike w.d. bars, it uses a horizontal rather than vertical force to transfer weight so there is greatly reduced "bounce" from uneven roadways. It's relatively inexpensive, greaseless, and lightweight. Users have been satisfied with its performance. If not they'll take it back and refund your money.

Do we need to know more to "try it"? Mine's on the way.

doug k

If this works well for customers, I would expect many imitations in the near future. W.D. bars are an effective but cumbersome design.
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Old 09-07-2012, 12:24 PM   #431
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I thought I might try to explain and analyze how the Andersen hitch provides the weight distribution to a tow vehicle. This is not easy, and I may not succeed, but here is my attempt. I will compare it with a conventional round bar system (RB), which uses bent bars which go into the hitch head, and are supported on the trailer side by snap up brackets and chains.

First, visualize the conventional RB from the side, lets say the road side. Sit on the ground (in your mind) and look at a hooked up TV and trailer. TV will be on the left, trailer on the right.

When hooked up, the RB system tries to twist the hitch head upward, or counter clock wise (CCW) by the lever arm provided by the length of the bar. The twist is provided over a few inches of metal which is inserted in the socket of the hitch head. The long end of the bar is supported by the chains from maybe 28 inches back on the bar. Those in turn are held up by the snap up bracket and apply additional force on the tongue, from about 28 inches back from the ball. The ball thus has the tongue weight on it, plus part of the forces from the chain from the spring bar . The CCW twist, is provided by the bent spring bar in the socket. We all know from years of experience that the conventional RB system works and re distributes forces forward, putting more downward force on the front tires.

Now look at the Andersen system from the same view, that is sitting on the ground on the road side of the hitch, TV on your left, trailer on the right. Assume that it is hooked up and properly adjusted.

The ball on the Andersen is a long tapers shaft from the top of the ball to the bottom where the triangular plate attaches. That ball shaft rides in a metal tapered socket which also has friction material in it (which we will ignore for now). The tapered socket is attached to the TV rigidly, via the hitch shank/stinger setup. Now pull rearward on the triangular bottom attachment with the chains which attach to the frame through some plastic bushings (ignore for now) and attach to the frame via the frame brackets. That rearward pull is resisted by the rigid trailer frame and the force is put forward on the frame of the trailer, and into the coupler and then to the ball, pushing on the rear side of the ball. We now have a triangle, with one short side (the ball and shaft) and two long sides, one the chains of the hitch, the other the frame of the trailer. With the ball and shaft being pulled from the bottom and pushed from the top there is a CCW twist applied to the ball/shaft side of the triangle. Since that short leg of the triangle can only move by twisting the metal tapered socket in which it rides, which twists the shank/stinger which goes into the TV we have the same result we had in the RB distribution system. Actually the short end of the triangle we are visualizing is about the same length in either the Andersen or the RB system. The twist on the TV hitch then transfers forces forward through the TV frame to put downward pressure on the front tires. Both the Andersen and the RB system accomplish the same thing, a CCW twist on the TV hitch box.

In the Andersen, the chains on the bottom, via the triangular plate, essentially do the pulling of the trailer, not the ball. The tongue downward force is still carried on the ball, and provides the pressure needed to make the friction material work for the anti sway feature of the hitch. The plastic bushings on the ends of the chains provide some flexibility in the system and the "anti-chug" feature that can help the ride quality.

The essential difference is that on the Andersen the ball/shaft carries the CCW twisting force needed for weight distribution, where in the RB system the bent spring bars do the CCW twisting. The twisting lever arm (short side of the triangle) is approximately equal in either system.

I am hopeful that this "sit on the ground on the road side of either hitch and look at them" approach will help people understand how both the RB and the Andersen work.

There are many good hitches on the market, and for 34 years I have used Reese and Draw Tight conventional WD hitches which were always satisfactory. I happened to need a new hitch, and found the Andersen. It works well and has some advantages in low weight, and smooth ride, as well as a very good built in sway control. However, every hitch out there is a bit different, and I don't think any are "bad" and should be excluded from your consideration. Each is somewhat different in weight, hookup operation, sway control, grease and lube needed and other factors. It is great to live in an economic climate where we have many choices. Depending on our perceptions and needs, we can decide the merits of each system and purchase accordingly.
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Old 09-07-2012, 12:41 PM   #432
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I made a drawing that shows my understanding of how the weight distribution works, it is a ruff drawing and I am sure many people will disagree with it.
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Old 09-07-2012, 12:48 PM   #433
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This is getting like those commercials "I'm 99.999 percent sure; than your not positive" or "Try it, you'll like it!"
NOPE 100% sure.
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Old 09-07-2012, 01:08 PM   #434
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NOPE 100% sure.
No question about it, 100% sure also.
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