A arms and a 3rd link

[Rick S.]

Artie,
This discussion is not about a point of view. Weather you realize it or not, it's really either black or white.
This is being discussed here because some people do want to learn, and would like to understand why this works. I'm only trying to educate those who want to understand.
I really seems that some of you are either offended, that someone else may have an understanding of something that you do not.  Or you are so arrogant that you can't possibly be wrong. I'm no post monger for sure. You don't see me giving advice to everyonere that asks a question here.  But you can bet that when I do post, it's about something that I've done my homework on. And that's no BS!   

[artie on edge]

I give up.Go for it boys. I hope its worth it.

[Nutz4sand]

I have seen the light and it is good.
I was looking at the pics and what not on "the other site" and finally figured it out. Now when I look at it I cannot see why I could not before. The biggest downside it appears to have is its not well accepted. But it should be.   

[fabr]

I think I may have figured out why we don't agree.Bear in mind we both know why it works and all we disagree on is you dogged determination to tell me I'm wrong. Soooo PLEASE keep an open mind here for a moment.OK?
 If I understand you right you say that the link forward attachment pivots on an axis running the length of the buggy. The key point to me is that you maintain that this POINT that lies along this AXIS is the axis the link pivots on.To me the AXIS the link pivots on is the AXIS that is perpendicular to the link or parallel with the heim bore (the heim bolt). That PIVOT  AXIS intersects the longitudinal AXIS at a POINT in space along it. Is this how we disagree even though we both understand the how and why it works? BTW keep your panties from bunching.It sounds like a valium may be needed soon!

[fabr]

I have seen the light and it is good.
I was looking at the pics and what not on "the other site" and finally figured it out. Now when I look at it I cannot see why I could not before. The biggest downside it appears to have is its not well accepted. But it should be.

I agree.I'm leaning strongly towards doing an H-arm setup on the rear of this buggy and the added link IMO is a good idea even if it's as a "floating nerf bar" for the lower arm.

[Engineer]

Really need pictures for those who haven't see this on "the other site". LOL

Looks like Rick found the "sweet axis".  Cad doesn't lie.

If your going to use Cardboard, I recommend putting it under the buggy to keep oil drips off the floor.....   

If you don't have Cad put the front mount on the axis of an A-arm, and the rear mount on that same arm.  Wouldn't even need a heim in the rear.

I don't see the gain of mounting the rear point on the carrier, except it looks trick and makes people scratch their heads.......

Kudos on the design Rick, and nice work on the build.  Did you find the point with a three point circle, or just trial and error?

[Nutz4sand]

Even if you do not have cad the arm they use is not on the "same" A-arm axis so to speak. It's commonality with the steeering tierod many speak of is if you see it in the pics is the pivot point on the frame is the same distance and height inward and above the A-arms frame mount as the actual A-arm pivots on the hub. Thus no binding.

I at first thought it was just like a wider A-arm which can be as wide as you can fit it to the other end of the frame. But its in a differnet area.

The forward rod has to connect to the hub to prevent the bushing wear if it connected right to the A-arm. Thats why it was brought into existance. The A-arms bushing wear. So it really cannot connect to the arm alone and do what it ws built for. 

[Rick S.]

Correct!

[Rick S.]

Mastrfabr,
My dogged determination is not to prove you wrong, You may find this hard to believe, but it's really not about you. It's about defending what I know to be fact. You are a well respected member on these sites. Alot of people will believe whatever you say, just because you say it's so. They line up behind you, right or wrong.  My terminology about the rod's axis is correct. I understand that there is a pivot point at the forward end of the rod, and this axis can be viewed from the side.  Yes, it is an axis, but not the rod's axis. The axis that the rod rotates about can only be viewed from the rear of the buggy. In vehicle design we call this the x axis.
The y axis is looking from the side and the z is from above or below. Everyone understands what we're talking about when we refer to the earth's axis.
It's not open to interpretation there is only one earth's axis. Same with the rod.
Yes, The earth rotates about the sun, but the sun is not the earth's axis. I will post the pics. of the link mock up. But what I really need to do is get some video. I think it would become crystal clear in a video.

[fabr]

I'm flattered by your assumption that I have a following.I don't really think that is the case but thanks anyway. I really believe we're understanding all of this the same way but can't seem to agree on words.That's the problem with typing shit instead of talking shit. Just a pun!  Post that vid up!

[Rick S.]

I do have a digital video camera, but I'm not sure how to re-size a video for posting.
Also we only have dial up out here in the sticks.  I think you know how that goes.
I could take a video and mail it to another member for posting. unless someone has another idea? Anyway these photos will have to do for now.
The first is from the rear. You can see the end of the axis rod, to the right and between the a arm attachment points. on the upright you can see the pivot that carries the rear of the link. the link itself can be seen between the a arms

This photo shows the entire fixture.

This photo shows the attachment point on the upright. I designed this so that the axis rod can plunge through the yoke. it can also be locked down to prevent the rod from plunging.
The plunge can be measured for actual deflection. It also must plunge to simulate different lengths for the link rod.

Here I simulate a link that originates from midway down the axis. To measure its deflection the forward link pivot is locked down on the axis rod. A dial indicator is fixed to the rod and it's contact point is set against the rods plunging yoke. I cycle the suspension and measure the deflection as the rod plunges through the yoke at the upright. With this gauge, deflection measurements for rod lengths midway and shorter will be measured at the upright.

This one shows a short link. You would never mount a link like this, but I show it, and measure it to prove the point. If I would have thought this out a little more, I would have made this gauge so the rod could have been pushed all the way between the a arms, to the rear housing plate. Where the link would actually be going rearward. This would have shown how the rod can even go to the rear.
I think I'll take this apart and mount it that way, just to illustrate. (I'll post another photo.)

This photo shows the longest link I can simulate with this gauge. If this gauge were full scale the link would be around 4 ft. For this measurement the rod is locked down at the upright and allowed to plunge along the axis rod. It's measured here with the indicator attached to the axis rod.


The short link deflection is .01 midway is .015 and long is .02
If you remember the debate on the other site, I never claimed there would be no deflection. only that there would be no bind. This gauge was designed to measure this deflection and simulate the axis with a rod. It is not a precision gauge. I built it in my garage.
Just like we do our buggies. If you use the link, and place it right, you will have similar deflection numbers to these. Maybe even better. On my gauge I can see how the heat from welding pulled the far end over a little. This is why the long link numbers are a bit higher than the short.  Normally the long link deflection numbers would be less than the short. At least this is what makes sense in my mind. Just imagine how much flex you get in your arms without these rods. I'd be willing to bet that it's 10 times these measurements. Think about it.

[Admin]

Rick, you can post videos on photobucket as well, thats were you host your pics right?

[Rick S.]

I'll try to figure it out this week. I've never even put a video from the camera onto this computer. I'm on vacation for the next 9 days, so I'll give it a try.

[Engineer]

Oh my.  You built that whole jig just to prove the link will work?     That's awsome.  You have the jig...... and they are arguing that it won't work because??


 

[Rick S.]

Because they have not seen the proof.
Here is the photo that shows the link going to the rear.
measured deflection was only .005
Which actually does confirm that the heat from welding warped it a little.
The sweet spot lies on an axis that runs the entire length of the buggy and beyond.