JBarca wrote:
Hi Joe,
OK I am not following your wording. The traditional WD hitch applies forces in different directions on the TT A Frame then the Andseron does.
However you used the words "standard spring-loaded wiper arm".
What are you referring to as a standard spring loaded wiper arm?
Do you mean a windshield wiper arm acting on a windshield of your auto? If so need a little help with the analogy.
John, I hope Joe doesn't mind if I try to answer on his behalf.gijoecam wrote:
I had a bit of a revelation last night on my way home from work... For those having a hard time envisioning how the system redistributes the forces, look at a standard spring-loaded wiper arm. The spring on the wiper arm applies force on the trailer the same way the chains/bushings on the Andersen system apply force to the trailer tongue.
Just thought I'd share it in case anyone had problems understanding what's pulling who where.![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/smile.gif "smile")
-Joe
I had a bit of a revelation last night on my way home from work... For those having a hard time envisioning how the system redistributes the forces, look at a standard spring-loaded wiper arm. The spring on the wiper arm applies force on the trailer the same way the chains/bushings on the Andersen system apply force to the trailer tongue.
Just thought I'd share it in case anyone had problems understanding what's pulling who where.
-Joe
Hi Joe,
OK I am not following your wording. The traditional WD hitch applies forces in different directions on the TT A Frame then the Andseron does.
However you used the words "standard spring-loaded wiper arm".
What are you referring to as a standard spring loaded wiper arm?
Do you mean a windshield wiper arm acting on a windshield of your auto? If so need a little help with the analogy.
The schematic diagram in this patent document represents what I would consider to be a standard spring-loaded wiper arm.
Now, think in terms of Part 2 being the ball mount, Part 3 being the ball (pivot point), Part 1 being one side of the A-frame and chassis rail, and Part 4 being the WD tensioning spring as used in the Anderson hitch. Spring tension produces a torque about the pivot point. This torque causes the wiper blade to be pressed against the windshield.
The blade's force against the windshield is the analog for the added force of a trailer's tires against the pavement. Per Newton's third law, the pavement, in turn, pushes up against the tires. It is this added upward force against the TT's tires which causes load to be removed from the TV's rear axle, with some of it being transferred to the front axle.
I think the spring-loaded wiper arm provides an excellent analogy for how the Anderson hitch can function as a weight distribution hitch.
Ron
Hope this new and old diagram helps
Just made this one up and follow the lines showing where the ball will
contact with the Anderson Hitch. The basic image is of how a traditional
WD Hitch or any traditional coupler system has the ball up against the
'front' of the coupler...towards the TV
This new image takes that and have added some lines showing where the
latch would now become the resting place for the Anderson WD forces
![[image]](http://img.photobucket.com/albums/v77/bentoy/Towing/AndersonWDhitchvectordiag1.jpg)
Repeat this vector diagram showing how the Anderson forces pull the
bottom of the ball/shank towards the trailer via the chains and plastic
springs.
As the trailer tongue now moves forward, towards the TV, it pulls the
coupler's front 'cup' or 'glob' (my verbiage) away from the ball. That
ball then moved towards the trailer (away from the TV) to rest on the
coupler latch.
![[image]](http://img.photobucket.com/albums/v77/bentoy/Towing/couplercrosssectioncontacta.gif)
Here are some other images so folks won't have to go back and forth
![[image]](http://www.andersenhitches.com/uploads/WD%20on%20frame%20med-sm.jpg)
![[image]](http://i23.photobucket.com/albums/b378/JBarca/Hitch%20Setup/Anderson/towball.jpg)
![[image]](http://i23.photobucket.com/albums/b378/JBarca/Hitch%20Setup/Anderson/trunrad.jpg)
![[image]](http://img.photobucket.com/albums/v77/bentoy/Towing/Andersonrenderingforces-1.jpg)
Ron Gratz wrote:
The schematic diagram in this patent document represents what I would consider to be a standard spring-loaded wiper arm.
Ron
The schematic diagram in this patent document represents what I would consider to be a standard spring-loaded wiper arm.
Ron
Ron, Sorry I cannot get that link to work. It says it needs a plug in. I'm on a 1 month old PC, Win 7 Pro and even updated Quicktime, Silverlight and Windows Live essentials in attempts to have it find the right plug in it is missing, still no go.
In this case an image is worth a lot of words. I'll try and get the image to work but not having any luck right now.
I can visualize the moments working, but still want to see your file.
Thanks
John
John & Cindy
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10
CC, SB, Lariat & FX4 package
21,000 GCWR, 11,000 GVWR
Ford Tow Command
1,700# Reese HP hitch & HP Dual Cam
2 1/2" Towbeast Receiver
2004 Sunline Solaris T310SR
(I wish we were camping!)
JBarca wrote:
I can visualize the moments working, but still want to see your file.
John, how's this?I can visualize the moments working, but still want to see your file.
![[image]](http://i1073.photobucket.com/albums/w386/RonGratz/WiperArmSchematic-1.jpg)
This schematic diagram represents what I would consider to be a standard spring-loaded wiper arm.
Now, think in terms of Part 2 being the ball mount, Part 3 being the ball (pivot point), Part 1 being one side of the A-frame and chassis rail, and Part 4 being the WD tensioning spring as used in the Anderson hitch. Spring tension produces a torque about the pivot point. This torque causes the wiper blade to be pressed against the windshield.
The blade's force against the windshield is the analog for the added force of a trailer's tires against the pavement. Per Newton's third law, the pavement, in turn, pushes up against the tires. It is this added upward force against the TT's tires which causes load to be removed from the TV's rear axle, with some of it being transferred to the front axle.
I think the spring-loaded wiper arm provides an excellent analogy for how the Anderson hitch can function as a weight distribution hitch.
Ron
WOW, that is exactly a perfect analog!
And pivot pin #3 has constant force on the back side of the pin just like the ball coupler latch.
You are towing the camper by part number 2 (the ball mount) and unless the wind drag, tire drag, tire brakes etc never overcomes the spring force, the TT will be pulled by the spring and continue to pull the camper into the back side of the tow ball only resisted by the coupler latch.
How did you dig up that cross section???
Thanks
John
BenK wrote:
...1. Has anyone factored in the weight of the tongue pressing down on the ball, countering the force trying to pull the latch into the ball?
the weight of the tongue only pushes 'down' on the ball and into
the tapered friction material...
...1. Has anyone factored in the weight of the tongue pressing down on the ball, countering the force trying to pull the latch into the ball?
the weight of the tongue only pushes 'down' on the ball and into
the tapered friction material...
What you appear to missing is that when the weight of the tongue is pressing down on the ball, the ball shaped contour of the coupler is resisting the tougue from moving forward on the ball. The only way the tongue can move forward is for it to raise up. The springs of the Anderson hitch would have to exert enough force to force the coupler to ride up the ramp formed by the curvature of the ball. It would take a lot of force to do that.
None of the vector drawings I've seen in this post account for the effect of the tongue pushing the ball into the dome shaped socket. The force it would take to cause the tongue to rise enough to allow it to move forward would be considerable.
I was able to get my hot little hands on a PDF copy of the installation instructions. In a nutshell, the tension on the chains is adjusted only enough to relevel the tow vehicle. It's not a fixed, one tension fits all adjustment of tension. A heavier tongue will require more tension than a lighter one.
Jeannie
JBarca wrote:
How did you dig up that cross section???
It's from the first page of the patent document.How did you dig up that cross section???
Ron
![[image]](http://i1073.photobucket.com/albums/w386/RonGratz/WiperArmSchematic-2.jpg)
Lady Fitzgerald wrote:
What you appear to missing is that when the weight of the tongue is pressing down on the ball, the ball shaped contour of the coupler is resisting the tougue from moving forward on the ball. The only way the tongue can move forward is for it to raise up. The springs of the Anderson hitch would have to exert enough force to force the coupler to ride up the ramp formed by the curvature of the ball. It would take a lot of force to do that.
None of the vector drawings I've seen in this post account for the effect of the tongue pushing the ball into the dome shaped socket. The force it would take to cause the tongue to rise enough to allow it to move forward would be considerable.
I was able to get my hot little hands on a PDF copy of the installation instructions. In a nutshell, the tension on the chains is adjusted only enough to relevel the tow vehicle. It's not a fixed, one tension fits all adjustment of tension. A heavier tongue will require more tension than a lighter one.
BenK wrote:
...1. Has anyone factored in the weight of the tongue pressing down on the ball, countering the force trying to pull the latch into the ball?
the weight of the tongue only pushes 'down' on the ball and into
the tapered friction material...
...1. Has anyone factored in the weight of the tongue pressing down on the ball, countering the force trying to pull the latch into the ball?
the weight of the tongue only pushes 'down' on the ball and into
the tapered friction material...
What you appear to missing is that when the weight of the tongue is pressing down on the ball, the ball shaped contour of the coupler is resisting the tougue from moving forward on the ball. The only way the tongue can move forward is for it to raise up. The springs of the Anderson hitch would have to exert enough force to force the coupler to ride up the ramp formed by the curvature of the ball. It would take a lot of force to do that.
None of the vector drawings I've seen in this post account for the effect of the tongue pushing the ball into the dome shaped socket. The force it would take to cause the tongue to rise enough to allow it to move forward would be considerable.
I was able to get my hot little hands on a PDF copy of the installation instructions. In a nutshell, the tension on the chains is adjusted only enough to relevel the tow vehicle. It's not a fixed, one tension fits all adjustment of tension. A heavier tongue will require more tension than a lighter one.
Then how does the one decouple the trailer from the TV?
The ball has to move rearward (away from the TV) and out of the coupler
glob (front section that has the coupler glob go below the ball
hemisphere.
Once away from the front of the coupler glob, there is NOTHING below
the ball hemisphere other than the latch pawl, which is moved out of
the way when the latch is lifted
That is what am trying to get folks to understand and why personally
think that force on the latch would not be good for it
The following diagram is for a Shelby Industries Class III Posi-Lock Coupler. This coupler seems to be quite robust as regards its ability to transfer forward thrust to the ball.
Unfortunately the instructions for the Shelby Industries Class IV A-Frame Coupler do not present the same level of coupler detail. However, I would assume the Class IV coupler is even more robust than the Class III.
I have added my interpretation of how trailer forward thrust is transferred to the hitch ball.
![[image]](http://i1073.photobucket.com/albums/w386/RonGratz/ShelbyCoupler.jpg)