Evener to single tree adjustable attachment

[Carl Russell]

Mark, the greater advantage would probably come from a deeper double-tree, making a larger diameter sweep, which would increase the mechanical advantage, but would not probably affect the proportionality.

I agree about the article. Someone want to take that on??:D

Carl

[Tim Harrigan]

A deeper double tree would accentuate the load distribution as Carl mentioned. The length of the double tree is not so much the issue as the relative difference in length from side-to-side. It would also be possible to design a evener that would shift the load to the lagging animal by pinning the load in front of the end points.

[Andy Carson]

I have plotted the effect of different offset depths (from 0 to 12 inches) on the load carried by the leader horse at various positions from even to ahead by 16 inches.

Overall, making the offset deeper makes the evener more responsive from the point of view of distributing the load. The cost for this is that the evener cannot tolerate large differences in horse position. You will notice, for example, that I have not plotted the 16 inch displacement for the 6, 8, 10, and 12 inch offset eveners. A foward movement of 16 inches is not possible on these eveners as that degree of movement will effectively straighten it out.

So, if you have horses that run almost even all the time and want to have a strong load “distributing” effect (rather than a load “evening” effect), it might be useful to increase the offset. If your horses often run uneven at times and you need to maintain the ability to have greater than 12 inch differences in horse position, it’s better to stick with the 4 inch offset. Based on these graphs, I would have predicted that a 4 inch offset would be best. It is very interesting that this seems to be popular.

[Tim Harrigan]

@Countymouse 23654 wrote:

…Based on these graphs, I would have predicted that a 4 inch offset would be best. It is very interesting that this seems to be popular.

Yes, isn’t it fun to prove in the laboratory what the old-timers proved in the field? And isn’t it fun to understand exactly what is was they proved by trial and error and perceptive observation. Maybe this is a case where ignorance is not bliss. Old farm tools are full of these subtle examples of mechanical advantage, from the seemingly simplest hand tools to more complicated threshing machines. These are the real innovations that advanced agriculture and are too often taken for granted.

[near horse]

Hi Andy,

Nice graph and so it brings up some questions for me (again). Would the value of having the larger setback be that it would more quickly shift the load to the leading horse as it pulled ahead and subsequently provide the slower horse the lever advantage to get back “up to even” sooner?

Point well made Tim. It’s funny (not ha ha) that these tools and machines, many of which were designed not too many generations back, are almost like piecing together remnants of an ancient culture. It’s hard to find (if any at all) the prototypes (the things that needed “tweaking” to be most functional) most stuff we see has had enough of the “bugs” worked out so as to be “in production”. I imagine the early not so perfect stuff got recycled into something else (back into the foundry).

But it’s interesting to think of some guys out in that field, say 150 years ago, trying out a new evener setup. You can almost hear them, “Well, what if you lengthened this side here ….”

“No, no. How ’bout setting the hitch point back a bit?”

“That might work. Let’s see …” “Jebidiah, you got your calcula .. err I mean abacus handy?”

When we look back at the design and fabrication of these old tools and machines (long before there was CAD), we should really be impressed. Unfortunately, I think we too often gloss over the time, thought and real ingenuity that produced this stuff. When we discuss the mechanics/physics of this equipment, both online here and at live events like NEAPFD, it prods me to take another look at why something is designed one way over another. But just as important, I feel a deeper respect for those who worked out the details of how to design “a better mousetrap.

I’ll say that if you want to spend time pondering all sorts of HD equipment, its mechanics etc, the Abbey Collection at Tiller’s (Scott, MI) is pretty unbelievable. I had the opportunity to spend a few hours in there and that was hardly enough. It was like the Smithsonian of HD equipment and really helped to have a knowledgeable person like Dick Roosenberg guiding us. I think Tim can attest to the quality of the collection. So if you’re in the IN, OH, MI IL area, see if you can make an appointment to check it out.

[Andy Carson]

I had a question about my math, so I’ll go into a little more detail about how one could do the lever arm calculations. I really do appreciate the questions, because I do flub up sometimes. I think I got this one right though.

The torque on the lever arm is given by the formula Torque = Force * Distance. Assuming there is no movement around the hitch point the torque on the heavy and light side is equal, that means F1*D1=F2*D2. As the total load is 600 lbs, we also know that F1+F2 = 600. That means that F2 = 600-F1. A substitution into the first equation yields F1*D1=(600-F1)*D2. Multiplication gives F1*D1=600D2-F1*D2. Rearranging gives F1*D1+F1*D2=600*D2, then F1*(D1+D2)= 600*D2 and finally simplifies to F1=(600*D2)/(D1+D2). Now it’s easy to plug in numbers. For a 4 inch off set with one horse ahead by 4 inches, one arm is 21.38 inches long and the other is 19.81 inches. F1=(600*21.38)/(21.38+19.81)=311 for the lead horse. 600-311 = 289 for the trailing horse. I have to admit, I did this a different way and got the same answer, but I think this is the way you were supposed to do this is school…

[CharlyBonifaz]

thank you, that helps 😀 I should have listened to my teacher instead of dozing off…

[LostFarmer]

Another way to look at it is to sum the moments about a point. If you pic the hitch point as the location that is in equilibrium and sum moments about that point, will get the same answers. I think your math is correct on this one. :rolleyes:

Now say on a pulling evener, if you fix the hook or allow the hook to pivot which is better. According to my calculations you could achieve the same thing with a hook that is fixed and extended back a distance.

In my case I use a simple double tree that has 1/2 inch increments that I can move a horse in or out. Leaving the hook to pivot it can make a difference to a smaller or weaker horse without having to have one horse ahead or behind to make the evener work.

My mentor and neighbor friend that got me started driving horses fabricates equipment. He is pushing 80 and still putzing around the shop daily. He once told me the longer he works on this horse stuff the more he realizes it is a mistake to get too far from the original. He has built over 50 sleighs now and about that many carts and wagons. His designs have evolved but come back to not far off the original. Another young welder kid took one of his carts to copy but did several things to make it easier to fabricate. The result was it pulled all wrong and was awkward. Humble pie tasted pretty bitter as he went back to what the old man had done.

[Tim Harrigan]

LF, I think you are going to have to be more descriptive or include some calculations for me to understand what you are getting at. The evener under discussion does not require one horse to be ahead or behind in order to re-distribute the load, but it will redistribute the load when that happens. That is the cleaver part of the design. You also have the option of moving one end in to shorten the lever arm for the stronger horse. That changes the load distribution when they are pulling even. So this evener does both, it allows one horse to have more of the load all the time, but it will also apply a differential correction in redistribution to the faster or stronger horse that forges ahead. The more that horse charges ahead the more of the load it has to carry, and the load shift increases at an increasing rate the more out of sync they get.

I would like a little more clarification on the system you are referring to.

[near horse]

@Carl Russell 23554 wrote:

Here are the pix I was supposed to post a couple of weeks ago.

43″ evener

Offset holes are about 1/2″ on center

Single-trees 29″ steel tube makes clevises 30″ on center

What happened to the pics of the evener? I also tried to look in the Gallery of Old DAP photos but it won’t let me access those. Am I in trouble or something : (

My farrier feeds with his team and is really interested in this evener — H_E_L_P!

NOTE – I used my super sleuthing skills to track down said photos on Carl’s FB page. Thanks Carl for keeping that stuff available. Still can’t get into the old DAP photos though.

[Ronnie Tucker]

lost farmers mentor is right you need to stay pretty close to what is tried and true ways.too many people try to reinvent the wheel. some improvements come about but nothing drastic.learn the basics.

[Author]

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