AO_hitech
SF Bay Area
Senior Member
Joined: 08/09/2004
View Profile
|
Stressor wrote:AO_Hitech, your mechanical reasoning skills are certainly far more advanced than my own. I stand in your shadow.
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/rolleyes.gif "rolleyes")
|
tluxon
Kirkland, WA
Senior Member
Joined: 08/12/2001
View Profile
 Offline
|
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 -
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
|
TnAnFLA
Nokomis FL
Full Member
Joined: 02/18/2005
View Profile
|
Since I'm always willing to throw gasoline on a fire, I've put on my flame suit, so here goes. One thing I don't recall seeing in this Odessey of a thread is that the strut bars are actually adjusted by placing them under a compressive stress. And when the TT trys to yaw, that places yet more compressive stress on that side of the hitch assembly. Since the four bar linkage is not square, the force applied to the yaw-ward side of the linkage is effectively trying to collapse a rigid acutely angled assembly from the top of the angle, which is real hard to do. That's one of the reasons I think the hitch assembly instructions have you place the strut mounting brackets at 25 plus or minus 1/2 inch from the ball coupler. That sets the length of the lever arm working against the four bar linkage. Conversely, when you make a turn with the TV you're not trying to compress the linkage, but rather "pulling" on the top of the acute angles, which much more easily collapse and allow the hitch head to translate laterally.
All that prattle aside, I do think that Milt's obsequious (sp?) photo of the hitch with the come-a;ong has it backwards. The TT doesn't "pull" on the linkage when it trys to sway, it actually "pushes " on it (I think).
Just my $.02
Andy
31' Itasca Impulse
|
tluxon
Kirkland, WA
Senior Member
Joined: 08/12/2001
View Profile
Offline
|
Stressor wrote: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. Milt,
You provided a link to "the Skeptic's Dictionary". If you look around their site you'll find "A Practical Guide to Critical Thinking". I would bet it would make an interesting read to you. In it you'll find that the first step is introduced like this: Quote:Step 1: Adopt the Attitude of a Critical Thinker
The first step to becoming a proficient critical thinker is developing the proper attitude.
Such an attitude embodies the following characteristics:
· Open-mindedness
· Healthy skepticism
· Intellectual humility
· Free thinking
· High motivation
... You may or may not subscribe to the critical thinking philosophy, but I believe you are an open-minded person and you certainly have a healthy skepticism. I'm also certain that you'd be willing to let go of firmly held beliefs if sufficiently disproved. However, it doesn't always come across that way to me and I think that may explain why sometimes I don't follow you and/or may respond flippantly. I apologize for this.
It is clear that you have gone to great lengths to try to make your point, and we have put a fair effort into our attempt at a rebuttal. Neither side has made much headway and perhaps we never will, but I think it only detracts from our efforts in this thread when we insult the opposing viewpoint with flippant or sarcastic remarks. It's easy to get frustrated when trying to get agreement on a concept that's difficult to explain and visualize without pictures, video, and maybe even hands-on manipulation. Let's try to stay cognizant of that as we continue to add value to this thread.
Tim
|
tluxon
Kirkland, WA
Senior Member
Joined: 08/12/2001
View Profile
Offline
|
TnAnFLA wrote:...I do think that Milt's obsequious (sp?) photo of the hitch with the come-along has it backwards. The TT doesn't "pull" on the linkage when it trys to sway, it actually "pushes" on it (I think). Hi Andy,
I guess it depends on how you define the sway of a TT. I think of sway as the TT tongue trying to move side to side and that motion being multiplied by the TV. The way I understand the Hensley, part of the genius of the hitch is its ability to give to a certain amount of this side-to-side movement without transfering any of the forces to the TV with any kind of lever arm. In fact, as you trans-rotate a 4-bar linkage with the proportions the HA has, it moves several inches side-to-side with only a very slight change in angle between the TV and TT (approximately 5° each way). I believe this is far more effective in dampening the affect of a swinging (albeit ever-so-slight) TT on the TV than if the TV and TT were welded together.
Tim
|
|
|
tluxon
Kirkland, WA
Senior Member
Joined: 08/12/2001
View Profile
Offline
|
Somebody correct me if I'm wrong, but isn't the primary function of the strut to keep the TT square to the back "bar" of the HA?
|
bettered
UpCountry SC
Senior Member
Joined: 07/26/2004
View Profile
|
Well Hello fellows, and here we go again. We should be grateful to Dave Whittaker and to Andy for their inciteful observations. I'd like to take Dave up on his theory if we can find some dollys. that suggestion would put all this model speculation to rest and offer indisputable proof that there is no lock. None whatever.
Facts are stubborn, particularly in view of highly charged opinions, which may or may not be correct. Facts cannot be accused of being incorrect, but sometimes we confuse facts with results because we've not made all the appropriate observations. That's an observational problem, not a factual problem.
Andy's explanation is exactly correct, and although he called it prattle, I must agree the explanation is a bit difficult to envision. Let me try it another way. The beauty of this linkage is that the side link connections on the TT side are wider than those on the TV side. Neither link can be collapsed, permitting a turn (or sway) until some translation of the front or rear link occurs.
The front link translates when the TV is turned. As long as the TT/TV combination is generally straight AND THE TT WHEELS ARE ON THE GROUND, no realistic side force imparted to the TT can be great enough to translate the rear link of the HA. Put the wheels on dollys and push the TT sideways. The rear link will translate easily and as you can push the TT as far as the linkage can turn - what is it 190* lock to lock?
The fact that the TT/TV combination when aligned (as in towing) will not permit the TT to initate any side to side movement makes the HA ACT AS THOUGH IT WERE LOCKED. Call it a virtual lock, because sideways friction of the TT tires and wheels prevents translation. Remove that friction and the TT is free to rotate behind the TV because the intial motion of the rear link will be translational.
Thank you Dave and Andy.
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
|
Ron Gratz
full time RVer
Senior Member
Joined: 12/27/2003
View Profile
|
Stressor wrote: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.
What an amazing statement coming from a person who endlessly lectures others on his interpretation of "scientific method". His "scientific method" allows him to fabricate his own theory of how something works and allows him to ignore evidence which might prove otherwise. Of course, the rest of us must abide by other "rules" which do not apply to him.
|
bettered
UpCountry SC
Senior Member
Joined: 07/26/2004
View Profile
|
tluxon wrote:Somebody correct me if I'm wrong, but isn't the primary function of the strut to keep the TT square to the back "bar" of the HA?
I don't think so Tim. The rear link wants to be square to the TT centerline, but it's so the TT will track straight. The primary function of the strut bar(s) is to prevent all motion of the rear hitch bar (the orange part) relative to the hitch ball in the yaw plane; that is, to keep the orange part from turning on the ball thus forcing all turning through the linkage itself.
Ed
|
Ron Gratz
full time RVer
Senior Member
Joined: 12/27/2003
View Profile
|
bettered wrote:tluxon wrote:Somebody correct me if I'm wrong, but isn't the primary function of the strut to keep the TT square to the back "bar" of the HA?
I don't think so Tim. The rear link wants to be square to the TT centerline, but it's so the TT will track straight. The primary function of the strut bar(s) is to prevent all motion of the rear hitch bar (the orange part) relative to the hitch ball in the yaw plane; that is, to keep the orange part from turning on the ball thus forcing all turning through the linkage itself.
Ed
The function of the struts is to ensure that the TT cannot yaw relative to the rear (upper) unit of the HA -- i.e., so the ball coupler cannot pivot (yaw) relative to the ball.
However, it is of interest to consider what happens if the struts are adjusted so that the longitudinal axis of the TT is not perpendicular to the HA's rear link. Let's say the TT is 5 degrees out of alignment. If the HA locks up when the TV is moving straight ahead, then the misadjusted struts would cause the "locked" linkage to tow the TT at a 5 degree yaw angle. In reality, the linkage is not locked and the rear (upper) unit will rotate until the TT tracks at an angle between 0 and 5 (probably closer to 0) degrees.
|
|
|
