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Physics of a counterweight


Simpleton7016

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I am considering the purchase of a counterweight for my 716H (e-bay item 7732905564). As I sit here at my desk (and away from my garage), I am having a hard time visualizing the physics of it. The main thing I want to accomplish is to add weight to my rear-end for use when snow blowing. However, I do lift the thrower a lot when making my turns. Won't this just make it heavier and more difficult for me to raise with my lift lever? What is the primary functional purpose of a counterweight - to add weight to the rear end or to add leverage weight to the snowthrower? The rear weight that I have now is extremely bulky and difficult to attach (it was a handy-man special from the previous owner). This counterweight looks extremely easy to install for winter-use, and like most everyone, the more time I can save, the better!! And what the heck is a "counterweight bracket" (e-bay item 7732906703)? Do I need this if I have a rear hitch lever-type assembly?
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On the older 'B' series tractors the rear lift went down as the front lift came up, thus, having a wt hanging in the rear lift tube makes the impl on front raise easier. On the newer tractor that had cable lift to the rear instead of a rod, both ends go the same direction. It is possible to re-rout the cable to get the same affect as the good ole tractors. There have been over the years many detailed, pictured posts here doing such a deed. Might try a seach for 716 rear lift or something like that and see what you find.
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The 716H uses the cable lift on the rear. As my 716H came from the factory, the rear lift went up at the same time as the front implement went up. This would make the attachment harder to lift if a weight were added. I just bought a different rocker shaft that had two cable attachments. One makes front and rear move together, and if you attach the cable to the other position the fron and rear lifts will move opposite. I think this type of rockshaft was developed when they came out with the heavy duty tiller, so that you could push the lever forward to lift it which gives you the ability to lift more weight. Any way, if you change to this type of rockshaft (I think mine is off a 7100 series tractor, but don't really remember), then you can change the direction of rear lift motion and have the rear going down when the front comes up. This will allow added rear weight to make the front implement easier to lift. Roy recently made this conversion to one of his tractors. You should be able to find that topic. That so called "counterweight bracket" is really the rear lift, to which the lift cable attaches, and it has the tube to which a tiller would attach, or the rear counterweight that you saw on ebay. Most AC700 series tractors did not have rear lifts from the factory. It was an option. I put one on mine.
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OK, that's what I thought, but couldn't remember for sure. Changing over the rocker shaft sound like a pain in the rump....or at the very least, a summer job. :) Thanks for confirming. I just want an easy way to add significant weight to the back of my machine. If I remember, I will take some pictures of the rear weight that I have today. I swear to God, I pinch my finger at least twice a year when I put that rear weight on and off! :(
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Take a look at page 20 - Lift Arm Installation in the following document. It shows an auxillary lift arm that was bolted to the lift shaft to allow the rear attachment to move in the opposite direction of the front attachment. If your 716 has a lift arm similar to the one shown you could fabricate a similar bracket you would not need to replace your existing lift shaft with one off a newer 7100 series or the later 7000 series. I've not been able to locate a part number for this "special lift arm" but thought it was interesting when I ran across it. http://www.simplicitytechpubs.com/6767PRINT/PDF_files/TP_100_2977_02_AT_S.pdf
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Erik, If all you want is more weight for the rear wheels, and don't need a counterbalance, then just make a bracket that bolts to your hitch to hold the weight. I use some of the 45 pound suitcase weights (were originally green) on the rear of my tractors for snow activities, like pushing and blowing. I will probably attach them to the rear lift of the 716H this year, since the hydrolift doesn't care as much as my left arm did with the manual lift. I haven't changed the rockershaft yet.
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Steve, it looks as if the special lift arm is just a piece of bracket put in place to allow the cable to attach to the opposite side of the lift arm allowing the rear implement to act backwards from the front. It looks as if adding this would allow the rear lift to not have to reroute the cable in order to acheave reverseing the the lift. Although I'll be the first to say I don't know that much about the RBT caractoristics, I thought that rerouteing the cable woulod do this, but it looks as if Simplicity came up with a better way. I think I recall someone saying that reouteing the cable changed the amount of lift height you had. Maybe this mod. solves that problem.
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The special lift arm that is shown in the link above is made onto the rockershaft that I bought. I wasn't aware there was a bolt on unit till now. If someone has one of those bolt-on units, that would be a piece that I would like to duplicate. It would eliminate the need to change the entire rockershaft in order to change lift direction. Dave, I had limited motion with the stock lift bracket, since the crimp on my cable would jam against the cable pulley and stop the motion before the hydraulic cylinder reached its limit. When the direction is changed, the pulley is removed, this prevents the jamming and will give a longer stroke on the lift. I think Roy saw this on his conversion also.
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Thanks for the picture, Maynard. Guess I wasn't thinking too clearly. Since I have the newer rockershaft that I haven't installed yet, I could get the dimensions from it. Maybe I will make one or two during the holidays, since I am off between Christmas and New Years. I think I know a couple of people who may be interested in these units, if I make some up.
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Let me make the first one for myself. From that I will know how much work it is going to be and also how much I would want to sell them for. According to Jack's, this part is no longer available from the factory.
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Finally got around to snapping some pictures of my rear weight... crude and effective, but i am in the market for something simpler and easier to install. Somewhere, either on this site or other, I saw a really cool box that someone fabricated where weight could be added one at a time. The weights even had handles for easy addition and removal. I can't find the pics anymore, but if someone could post them, that would be great. Side note: Will wheel weights work in and of themselves, or is additional weight needed even with wheel weights?

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I solved the same problem by going to McDonalds a few extra times... no back tire spin at all... I suggest that the weights added are better for your heart however..
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That is a good idea you have for weight on the back of your tractor.I had the same problem on the back of my AGCO 2027 Diesel not knowing what to put in the weight box.I just bought 5 bags of salt ,that way i dont have to worry about rust and such.When spring is here i will just fill the softner.
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