Counter-balance Lift Assist using Rear Weight

[Handy Don 12,663]

There have been a lot of threads that discuss ways to rear-mount weights to offset front loads or to help with traction.

What I'm wondering is: Has anyone has ever put the rear weights on a pivot with a lever that pushes a shaft under the tractor to give a lift assist?

One thought I had was a shaft similar to a snowblower lift but it would come from the rear and attach to the back side of the "flag" (the flag being attached to the rock shaft arm).

The weight pressing down at the rear translates to upward lift force at the front.

Depending on the leverage at the rear mount, 100 lbs of rear weight could get directly translated into 100 lbs or more of lift assist. In concept, not unlike a teeter-totter.

The weight is still in the back doing its traction job but by allowing it to pivot up and down, it is also helping with a front-mounted heavy blower or a scoop bucket (or in my case, a flail mower).

If this has been done, I'd sure appreciate the doer sharing pics of the design!

[SylvanLakeWH 26,155]

[ebinmaine 68,887]

9 minutes ago, SylvanLakeWH said:

Pass the popcorn...

[DennisThornton 4,769]

New to me.

[rayshorses 102]

The old Preistman excavators had a similar concept. The counter weight slide back and forth to allow the long reach boom balanced. I think your idea would be alot easier than trying to tighten the spring we have now.

[JoeM 7,874]

Strap a 2x4 under that rear axle and stand on it to see what happens. ??

 

 

[Handy Don 12,663]

1 hour ago, rayshorses said:

The old Preistman excavators had a similar concept. The counter weight slide back and forth to allow the long reach boom balanced. I think your idea would be alot easier than trying to tighten the spring we have now.

I can see these were moved by a cable system linked to how far the boom was deployed. Neat.

Tower cranes regularly use cable-controlled sliding counter weights, too. Movement is based on strain gauges that detect "bend" in the tower as the load increases or decreases--can even accounts for windage. 

It is the springs I'd like to ditch. They are a pain to install and their force depends on the amount they're stretched so it isn't even. And they mount at an angle to where the force is needed.

 

[wallfish 17,114]

There was a post a while back where the guy did something similar. Had the weight in the back and it lift assisted his snow plow. Couldn't find the thread but will keep looking.

[lynnmor 7,388]

With 100 pounds on the front and 100 pounds on the front, will put 200 vertical pounds on the pivot point, so keep that in mind if you build it.

[Handy Don 12,663]

50 minutes ago, wallfish said:

There was a post a while back where the guy did something similar. Had the weight in the back and it lift assisted his snow plow. Couldn't find the thread but will keep looking.

Thanks, I hope you find it. I did a bunch of searches with words I thought made sense, but came up empty.

 

42 minutes ago, lynnmor said:

With 100 pounds on the front and 100 pounds on the front, will put 200 vertical pounds on the pivot point, so keep that in mind if you build it.

Yes. If the front load is 200 lbs against the lift mechanism and the assist from the back is 100, and the assist shaft and the front lift shaft are aligned, then the forces would be:

-200 backward against the front of the flag

-100 frontward against the back of the flag

The extra 100 frontward to balance things out comes from the tractor lift through the rock shaft arm so its pin need only carry 100lbs.

The only 200lb pin is at the place where the front load attaches to the lift shaft.

 

The rear weight geometry would need care since it still has to safely support 100lbs and accommodate the leverage forces at the pivot from the lift assist action and any tractor movement. A simple inverted "L" bracket would have 100 down from the weight and 100 rearward as the resistance to the assist, so the pivot must handle those loads comfortably.

 

This would permit removal of the lift shaft assist spring for single stage blowers or plows. If no new load is being added to the front, no changes needed. But a front support spring might still be needed to balance the lift forces against a tilting implement (I'm looking at you, right side balance spring on the 2-stage blower).

 

Yep, a lot of variables. That's why I'm interested is seeing one that works and how it was done!

[Lee1977 6,873]

4 hours ago, wallfish said:

There was a post a while back where the guy did something similar. Had the weight in the back and it lift assisted his snow plow. Couldn't find the thread but will keep looking.

Extend the snow plow frame and add weight there to take weight off the plow, that would be easy. The blower is different it would take a cable a pulley up under the tractor to reverse the motion to lift the blower.

[Mickwhitt 4,796]

I looked at the idea of doing the above when I built my snow plow A frame. 

But I couldn't see a need when the plow needs down pressure rather than assistance in lifting, which is more than catered for by the lift mechanism as is.

I fitted a separate weight rack above the tow hitch to increase traction weight.

The pivot point would have to be pretty beefy if you were going to put weight on both ends of the plow frame, as would the attachment point as all this weight would be pulling down on the locking cams. 

Im not sure there would be any benefit in taking this approach but if anyone wants to do it and show the results I'd be interested. 

Mick 

 

 

[ebinmaine 68,887]

1 hour ago, Mickwhitt said:

Im not sure there would be any benefit in taking this approach but if anyone wants to do it and show the results I'd be interested

For a plow I'd agree. 

We don't run a blower but I can see them being a bear to lift. 

[squonk 41,649]

Putting weight here means putting pressure there. I can't help thinking of the late 60's and early 70's tractors that I've run across with the cracked hood stands from the pressure that the twisting force of the rockshaft puts on it. These tractors were designed for "so much" and adding weight or other mods to pull more or lift more than the original design will compromise something else.

Edited February 11, 2021 by squonk

[JoeM 7,874]

46 minutes ago, squonk said:

original design will compromise something else

Yep, at work I called it the butterfly affect.

We would have a bracket or arm that in time would fatigue and crack. Minor fix. Reinforced the arm and the pin would rip the eyes out of the machine, major fix.  

Have to make sure the juice is worth the squeeze!

 

Mike I liked your idea of putting wheels on the blowers. I thought if those were caster wheels might not even have much of a need to pick up the blower??

[The Tuul Crib 7,338]

Sounds like fulcrum to me.

or maybe it's levity! 

[ebinmaine 68,887]

58 minutes ago, JoeM said:

caster wheels

Joe I've experimented with that a little bit and I found that the caster wheels need to be fairly large and are not prone to wanting to spin on the snow and or rough ground

[squonk 41,649]

Yup thought of casters but I rareley turn with the blower down and find the tractor will steer better with the blower raised and more weight on the wheels.

[JoeM 7,874]

1 hour ago, ebinmaine said:

rough ground

I was thinking asphalt or concrete.

 

I have a trail mower that I use to rough cut the banks and it has 6 inch zero turn casters on the front. If you keep them greased they spin pretty good. Might be to big for blower??

 

You and squonk live the snow country and a blower has to be an asset. We got like three to four over night and the ground (my gravel drive) is frozen and I can plow with the shoes up.  

 

 

 

 

[ebinmaine 68,887]

21 minutes ago, JoeM said:

thinking asphalt or concrete

I was wondering that.

 

I think the larger caster wheels like you're talking about might be perfectly fine behind a side extension wing. 

 

Certainly something I'm going to keep in mind when and if I get around to making something out of the monster walk behind I have. 

[Lee1977 6,873]

6 hours ago, squonk said:

Putting weight here means putting pressure there. I can't help thinking of the late 60's and early 70's tractors that I've run across with the cracked hood stands from the pressure that the twisting force of the rockshaft puts on it. These tractors were designed for "so much" and adding weight or other mods to pull more or lift more than the original design will compromise something else.

Using weight would be the same as using springs, would still take the same amount of force to lift the implement, just lessen the force require to pull the lift. 

[squonk 41,649]

34 minutes ago, Lee1977 said:

Using weight would be the same as using springs, would still take the same amount of force to lift the implement, just lessen the force require to pull the lift. 

Correct, BUT I know how guys are. Make it easy to lift and next thing you know they are trying to lift something heavier. And before you know it, something else breaks. I've seen dozens of horses with cracked hood stands. They didn't get that way sitting in a barn doin nothing.

[RandyLittrell 3,885]

I see no point for a blade, but a counter balance for a blower would be nice. I think a better plan would be for the weight to be on its own frame and pivot point ahead of the rear wheels. This way it would support itself and just provide lift towards the front the blower subframe. No added stress to the original lift. 

 

 

 

Randy

[Handy Don 12,663]

Man, take a day off from reviewing posts and it's like being back at work after vacation with your inbox stacked to the ceiling.

Thanks for the commentary!

 

On 2/11/2021 at 7:29 AM, squonk said:

Putting weight here means putting pressure there. I can't help thinking of the late 60's and early 70's tractors that I've run across with the cracked hood stands from the pressure that the twisting force of the rockshaft puts on it. These tractors were designed for "so much" and adding weight or other mods to pull more or lift more than the original design will compromise something else.

Agreed. Presumably there would be a solid rear frame already set up for weight, like some of the 2" receiver setups, and thought through to make sure all the forces are accounted for. The weight is all carried at that end down to the transaxle (if only weight were the only goal, then @ebinmaine's filled tires and wheel weights make more sense ).

If the counterbalance is connected directly to the front via, say, the pushrod flag, then there is no extra force on the rockshaft or the hoodstand rails involved in the lifting. See the first sketch below.

 

23 hours ago, Lee1977 said:

Using weight would be the same as using springs, would still take the same amount of force to lift the implement, just lessen the force require to pull the lift. 

Yes (and if that is less, then the forces on the rockshaft are also less).

 

3 hours ago, RandyLittrell said:

I see no point for a blade, but a counter balance for a blower would be nice. I think a better plan would be for the weight to be on its own frame and pivot point ahead of the rear wheels. This way it would support itself and just provide lift towards the front the blower subframe. No added stress to the original lift. 

Randy

Right, if the implement uses weight to do its job, reducing weight (downforce) makes no sense.  

Definitely more for blower, sweeper, front-mounted rotary mower, scoop bucket, or my fairly heavy flail mower.

Can you explain how you see the pivot ahead of the rear wheels being better than a pivot behind the axle? Maybe just to make the counter-balance lift rod shorter?

 

On 2/10/2021 at 11:50 PM, Lee1977 said:

Extend the snow plow frame and add weight there to take weight off the plow, that would be easy. The blower is different it would take a cable a pulley up under the tractor to reverse the motion to lift the blower.

One goal is to not have a plow frame. I keep thinking cable but as you surmise, getting the motion reversed is the trick! It'd take, I think, two pulleys in back and two pulleys in front. See second sketch below.

 

Quick (and admittedly crude!) sketches of current thinking just to show where the general ideas.

First is the via a counter-balance lift rod connected to the existing lift rod. Weight pivot/lever is a modified version of many existing rear weight support designs

 

This is a rough idea of the cable routing method. I'm sure with some thinking it could be better!

[squonk 41,649]

How much weight are we going to put on the front to keep the wheels on the ground.