Pushing with a 3pt hitch...

[Max2310]

A while ago, I saw in a post someone who mentioned that a 3 pt hitch is made to pull not to push. A wasn't able to find some concrete information on that subject. I do agree that it must be stronger pulling but is pushing is something that should be avoid? Since I saw that post, every time I'm using my back blade in reverse, I think of that and ask myself that same question

 

[BrianWillan]

A while ago, I saw in a post someone who mentioned that a 3 pt hitch is made to pull not to push. A wasn稚 able to find some concrete information on that subject. I do agree that it must be stronger pulling but is pushing is something that should be avoid? Since I saw that post, every time I知 using my back blade in everse, I think of that and ask myself that same question

Think of it this way.... Most 3 pt hitch snowblowers are designed to be operated while driving in reverse. IE pushing. Granted from a simple physics stand point you can certainly pull more than you can push, but I imagine that it is all relative.

Cheers

Brian

 

[JohnDeere4300]

A while ago, I saw in a post someone who mentioned that a 3 pt hitch is made to pull not to push. A wasn't able to find some concrete information on that subject. I do agree that it must be stronger pulling but is pushing is something that should be avoid? Since I saw that post, every time I'm using my back blade in reverse, I think of that and ask myself that same question

You can read this....hope it helps.



http://www.tractorbynet.com/forums/attachments/50397-3-pt-hitch.html

 

[PILOON]

I push snow, spread gravel all the time in reverse.
Also one is always pushing when using a rear mounted snow blower.

As with all ground contact implements you should only push/pull and not ram or slam into hard contact.
In other words don't collide with an object, if you want to extract a rock or root ball, the safe technique would be to 'kiss' it and reverse applying power as you lift the 3-point, i.e., lift and roll it out!
Naturally backgrading with smaller, like 3-4" stones should not be a problem.

Let the hydraulics do the hard work, they will act like a cushin or buffer.

 

[zzvyb6]

Push or pulling with a 3 pt hitch mechanism is not about strength, but about load reaction mechanics. A blade, rake, plow, tiller etc. hitting an obstruction will tend to cause the implement to raise when the hitch geometry is properly arranged in forward motion. In reverse, the same geometry will tend to buckle the load path: The implement will dig in instead of wihdrawing.

Sometimes there is an advantage for each method. For example, I often run my 3pt tiller over my gravel driveway. Going forward, the tiller just jumps over the packed stone. Going in reverse, the tiller digs in and there is no jumping around. Likewise, if you mount a snowplow off the back of your tractor and push it in reverse, the plow will gouge a rut if it can dig in. Same thing if you go forward with it and the mount is angled downward. If you mount the frame ramping upward from the tractor frame to the plow, it will not dig in and ride an uneven roadway pretty well.

Its all about load path (geometry).

BTW: That's another reason I'm not a fan of loader mounted plows. Most operators set the plow frame at a downward angle and wind up messing up the koader frame, driveway or can't steer it.

 

[Spudland_Dave]

Think of it this way.... Most 3 pt hitch snowblowers are designed to be operated while driving in reverse. IE pushing. Granted from a simple physics stand point you can certainly pull more than you can push, but I imagine that it is all relative.

Cheers

Brian

Well, thats true, but technically your not pushing the snow at all...only pushing the weight of the "Blower Box" to keep it fed of snow...so your not really applying undue stress..

Take it from someone who bent a 3pt arm like a Taco with my Box Blade...

What I now do is only box blade in reverse on Loose stuff I've piled up or spread out...no more reverse scraping...The same goes for snow blowers, its not an issue to snowblow the fresh stuff, but I wouldnt just ram it into a snowbank full of ice & such...

 

[JB4310]

It really is just the lift arms or draft arms, what ever the proper term is for them, that are the weak link. There should be a way to make them capable of pushing what ever the tractor can throw at them. something like a trucks front plow frame.

Many of these implements are designed to be used in reverse, so no one can say you should never push with your 3 pt. I agree with the snow blower it's kinda pulling itself with the auger, but boxes and blades are designed to push as well as pull the tractors 3 pt systems should be built to handle it.

The rear of the tractor is known to be the heaviest, seems like all that's needed is to make the arms a little heavier.

I installed a truck plow on my 3 pt this year, and as great as it worked I couldn't recommend it to others here in good confidence for 2 reasons.
First, I think I did bend one of my arms a tad, almost not perceivable, but I was ramming snow banks with it, something I said I was not going to do. The rear plow was originally supposed to just be for cleanup after the front loader but it became apparent the the plow was so much quicker and I just used the loader to manage the banks and piles made by the plow.
Second, I thought I might take some heat for making such a recommendation that many here believe to be unorthodox or destructive.

So I won't recommend it to others but I will keep pushing with mine, My lift arms are pre bent right at a critical point making them vulnerable to further bending, just may reinforce my lift arms and be a little more respectful of the geometry.

JB.

 

[3RRL]

A while ago, I saw in a post someone who mentioned that a 3 pt hitch is made to pull not to push. A wasn't able to find some concrete information on that subject. I do agree that it must be stronger pulling but is pushing is something that should be avoid? Since I saw that post, every time I'm using my back blade in reverse, I think of that and ask myself that same question

Like Dave and JB said, many of the implements are made to push, not just pull.
That said, most of the lower drag links (or lift arms) have 2 bends in them. One is at the housing of the tractor and the other is at the swivel eyes so that the end of the links are facing straight back, perpendicular to the lift pins on the implement. That means there is an inherent weakness designed into them to take compressive load. They are not in a straight line with the load being pushed backwards so they could bend much easier than when pulling with them.

I personally don't move snow but do a lot of ground engaging dirt moving with my box blade. I've learned to be careful and try to push already loosened dirt by pushing in reverse. When I pushed really hard dirt and boulders, I bent those links. Here are a couple photos of the designed bends in the links on my tractor, and also of the bent ones.



Since I really wanted to use the pushing in reverse feature, I ended up reinforcing my drag links. I used a couple old 3/4" thick scarifiers and welded them to the bottoms of the drag links once I straightened them out. they are welded with heavy gussets and now the links form a "T" with the reinforcement on them. They are much stronger now. I do a lot of bulldozing in reverse and since this modification, I've had no problems of bending, nor has the tractor mount (for the links) suffered any damage. I still try to watch how much force I use pushing in reverse since my tractor is 55hp and weighs about 8,000lbs loaded. I still advocate using the implements in reverse since there are great benefits from such use. Just be sure you have the reinforcement and watch what you are doing and never slam into your object pile. That goes for going forward or reverse and for FEL use as well.
Rob-

 

[JB4310]

Since I really wanted to use the pushing in reverse feature, I ended up reinforcing my drag links. I used a couple old 3/4" thick scarifiers and welded them to the bottoms of the drag links once I straightened them out.

I know I'd seen that type of reinforcement before, don't know if it was yours or someone else's but that looks like the best way to strengthen those arms without interfering with the range of movement or accessory placement on the 3pt or PTO.

I'm gonna do the same thing.

JB.

 

[kthompson]

I understand the design of harnessed used on horses or mules was so they could push the load with their shoulder and not really pull it as they could push more than pull. Suspect a human can push more than we can pull also.

On running the tractor in reverse to me the most likely time to damage it is with speed and then hitting that sudden load or stop. Have done a fair amount of box blade, rear blade and bush hogging in reverse that if memory is correct with no damage. But do so in slower speeds. Have also learned to have both stabilizer tight to help prevent the side shift to the lift arms. Don't take this as any brand bashing but some brands just use lighter lift arms than others. Noticed that very much when really looked at tractors with Cat 2 lifts. Some had Cat 2 arms that were same weight as their Cat 1 models, which were about normal with other companies on Cat 1's. You also could have a brand who used the Cat 1 in HP range that others have gone Cat 2 arms or even a dealership (importer also I guess) installed lighter weight than that model calls for to make a little extra.

 

[AKfish]

Since I really wanted to use the pushing in reverse feature, I ended up reinforcing my drag links. I used a couple old 3/4" thick scarifiers and welded them to the bottoms of the drag links once I straightened them out. they are welded with heavy gussets and now the links form a "T" with the reinforcement on them. They are much stronger now. I do a lot of bulldozing in reverse and since this modification, I've had no problems of bending, nor has the tractor mount (for the links) suffered any damage. I still try to watch how much force I use pushing in reverse since my tractor is 55hp and weighs about 8,000lbs loaded. I still advocate using the implements in reverse since there are great benefits from such use. Just be sure you have the reinforcement and watch what you are doing and never slam into your object pile. That goes for going forward or reverse and for FEL use as well.
Rob-

Rob - nice work!

We all do it (reverse plowing, etc.). It's really a matter of being sensible about what you're doing.

And as mentioned - you can cause damage to implements going in a forward direction, too. I bent the vertical lift arm on the draft link while using my 7' rear blade. I was down in a road ditch with narrow shoulders and caught the right corner of the blade on the shoulder while moving forward. The momentum of the tractor and the leverage of the blade "pretzled" the opposite lift arm. Lesson learned.

The great thing about this site is the opportunity to learn from the experiences of others.

P.S. Are the gussets meant to allow contraction/expansion of the shank during the welding process instead of causing distortions to the 3pt arm? Thanks.

AKfish

 

[3RRL]

P.S. Are the gussets meant to allow contraction/expansion of the shank during the welding process instead of causing distortions to the 3pt arm? Thanks.

AKfish

Thanks AK,
Regarding your question, I re-read what I wrote and saw it was misleading.
What I meant to say was the weld was laid down in many passes so the weld itself ended up like a 1" wide gusset.
I merely tacked the reinforcing steel several places before running my first set of passes. I ran several passes and let the links cool down slowly...no special treatment after that. I guess I could have stress annealed them after welding but elected not to do that. One thing for sure, they came out very very heavy duty.
Rob-

 

[tatra805]

Would like to add to the push-pull thing:

- 3pt arms and leverage points are not a push design but a pure pull design
why a dozer or fel has a different construction. Does not mean you cannot push with it but design is pull. (self centering btw)

- reversing over long distances, eg snow pushing etc wears out your gearbox faster. Small gears high rotation and you get the point. (check your oil temp when reversing over prolonged period compared to similar labour in forward mode and you will see the difference )

- differentials (the ring and pinion teeth) are set up to grip in forward drive and not in reverse, Therefore never pull in reverse (and so, push in reverse) Jumping teeth on R&P are not something you are really waiting for. Possibly some gears in the gearbox / drivetrain also.

- Reversing you have more grip with your tires(might seen funny but is the case) that means you will actually be able to push harder in reverse before your tires start slipping. Slipping tires can be a safety margin to not damage your drivetrain.

Add the above together in a scenario where speed, traction and inertia come together with an abrupt stop and yes you will break, bend and damage something.


about the horse harnesses: the point of using a collar versus a breast harness is to enable the horse to throw at best its weight in the harness for ease and power on torque requiring moments. (collar better) But also and in first place that it is quite hard to attach something at the back of a horse to pull something(no hitch there)

 

[Knight]

Would like to add to the push-pull thing:-

about the horse harnesses: the point of using a collar versus a breast harness is to enable the horse to throw at best its weight in the harness for ease and power on torque requiring moments. (collar better) But also and in first place that it is quite hard to attach something at the back of a horse to pull something(no hitch there)

You could use a rope and tie a horse tail to load knot.

 

[600rider]

I think the most important thing to remember is to adjust your sway chains so there is not a lot of play side to side as that is what will bend your 3ph arms when you hit something immoveable. When you have everything adjusted right I belive it is equaly strong and pushing or pulling will be ok. I do not belive there is any disclaimer in my owners manual that says DO NOT PUSH WITH THE 3PH! just be smart about it. Ken.

 

[kebo]

Question for 3RRL..... I notice you have top-n-tilt with tilt on BOTH sides. I was reading the CCM website and it was saying that it's not good to have tilt on both sides. The reason they gave was that you could possibly apply downpressure on both sides thus lifting the rearwheels off the ground and upsetting the machine or possibly causing something else bad to happen. Have you ever given that any thought??

 

[3RRL]

Question for 3RRL..... I notice you have top-n-tilt with tilt on BOTH sides. I was reading the CCM website and it was saying that it's not good to have tilt on both sides. The reason they gave was that you could possibly apply downpressure on both sides thus lifting the rearwheels off the ground and upsetting the machine or possibly causing something else bad to happen. Have you ever given that any thought??

Good question kebo,
I don't want to deviate to much from Max's thread about pushing with the 3pt, so forgive me...
I purposely used 8" stroke very big 3-1/2" cylinders with 1-1/2" rods for the side links. I was trying to get the set up to apply down pressure with the box blade when fully extended. Well, I miscalculated and even fully extended there is still about 1" gap when fully extended on both sides. What it does do successfully is allow me to cut gutters easily that way since the box is shoved down into the ditch pretty good. To me, that is a good thing. Again, you just need to be aware that it can lift the tractor up a little and use your head when doing work with it.
Here is a video. When fully tilted, you can see the cylinder just starting to lift the tractor rear tire.
Rob-

 

[AKfish]

I think the most important thing to remember is to adjust your sway chains so there is not a lot of play side to side as that is what will bend your 3ph arms when you hit something immoveable. When you have everything adjusted right I belive it is equaly strong and pushing or pulling will be ok. I do not belive there is any disclaimer in my owners manual that says DO NOT PUSH WITH THE 3PH! just be smart about it. Ken.

Ken, very good point about the sway link chains. I probably adjust mine 2-3 times every hour of use. So, you always need to keep payin' attention to them.

But... when you really get goin' on a project - it's not always "convenient" to stop and take up the slack. So, you need to be paying attention and cautious when pushing in reverse because with some sway in the 3pt; things can go real wrong - real fast!

One additional point to consider regarding pushing in reverse on the 3pt. The 3pt normally "floats" and when pushing into a berm or pile the arms will move up the slope of the pile. But, there's only so much upward rotation available before the arms "bottom out" or stop. If you've got a big pile and some momentum behind the tractor - when the 3pt stops moving upward - the 3pt links - can bend!!

AKfish

 

[600rider]

AKfish
That is true about running up a pile with the 3ph but I have had 3 tractors with 3ph and have done some heavy pushing in hard clay soil and probably even abused the tractors some but have not bent an arm on any of the tractors in over 15 years, maybe I've just been lucky! but with proper adjustment you have less of a chance of bending something. My Kubota B7510 has a cotter pin to lock the turnbuckel where I put it so it doesn't lossen up.

 

[Max2310]

This is all very interesting, thanks!! It's greatly appreciated!

Max