Boom pole and top link

   / Boom pole and top link #11  
Compare a typical 3-point boom to the lift arm of a post hole digger to see what I think the OP meant.

Bruce
 
   / Boom pole and top link #12  
How about making it bend in the middle like the newer backhoe booms? This would allow you more clearance for whatever you were trying to lift.
 
   / Boom pole and top link #13  
How about making it bend in the middle like the newer backhoe booms? This would allow you more clearance for whatever you were trying to lift.


Most of the boom poles I have used have about a 60 degree bend in the boom about 18 to 24 inches from the end, works pretty good.
 
   / Boom pole and top link #14  
So what is really the question??

The style that require the separate toplink lift more weight, but not as high.

The style that is like a PHD (without using the TL), will lift higher, but wont lift as much weight
 
   / Boom pole and top link #15  
   / Boom pole and top link
  • Thread Starter
#16  
So what is really the question??

The style that require the separate toplink lift more weight, but not as high.

The style that is like a PHD (without using the TL), will lift higher, but wont lift as much weight

How did you arrive at this generalization?

If the boom is long (tall), the force vectors bring the weight of the load very close to the far ends of the three point lower arms in spite of carrying the load some distance clear of the tractor.

allowing a load nearly equal to the capacity of the lift. Adding a TL does not change this relationship.

The "typical" boom pole does tend to act more like a cantilever than a crane however.

Something I have never liked for moving heavy loads. And if it's light and low, I just use the bucket
 
   / Boom pole and top link #17  
How about adding a hydraulic top link for additional functionality?

Just a random thought.

That works well for me, with a regular 3pt type.

The ones without the top link will pivot higher and faster - which requires more power from your 3pt as you double the speed/height, you need more lifting pressure.

--->Paul
 
   / Boom pole and top link #18  
How did you arrive at this generalization?

If the boom is long (tall), the force vectors bring the weight of the load very close to the far ends of the three point lower arms in spite of carrying the load some distance clear of the tractor.

allowing a load nearly equal to the capacity of the lift. Adding a TL does not change this relationship.

The "typical" boom pole does tend to act more like a cantilever than a crane however.

Something I have never liked for moving heavy loads. And if it's light and low, I just use the bucket

The top link style lifts a 1:1 ratio, lift the 3pt 2 feet and the boom raises 2 feet.

They type without the top link work like a sissors lift, multiplying the height & speed of the end of the boom pole - depending on the angles used, could lift 2x as high, and require 2x as much power from the 3pt.

--->Paul
 
   / Boom pole and top link #19  
How did you arrive at this generalization?

If the boom is long (tall), the force vectors bring the weight of the load very close to the far ends of the three point lower arms in spite of carrying the load some distance clear of the tractor.

allowing a load nearly equal to the capacity of the lift. Adding a TL does not change this relationship.

The "typical" boom pole does tend to act more like a cantilever than a crane however.

Something I have never liked for moving heavy loads. And if it's light and low, I just use the bucket

The top link style lifts a 1:1 ratio, lift the 3pt 2 feet and the boom raises 2 feet.

They type without the top link work like a sissors lift, multiplying the height & speed of the end of the boom pole - depending on the angles used, could lift 2x as high, and require 2x as much power from the 3pt.

--->Paul

Correct you are Paul. (rambler)

The 3PH by nature is a parallelogram linkage. Allthough most of the time it is not set up as a perfect parallelogram. Even adjustments made to the toplink length and location (mounting hole) can effect lift capacity. If it were set up as a true parallelogram though, its lift capacity would be the SAME at ANY point on the boom. (provided enough front end weight).

Think about it this way, The amount of travel distance of the hooking point on the boom in relation to the amount of travel at the "ball ends" of the 3PH is going to be how much you can lift.

If you have a boom pole and set the 3PH up in a true parallelogram fashion, the hook of the boom, even 8' back, will have the exact same amount of travel as the 3PH ball ends. You can even modify (with toplink adjustments) the 3PH to where the hook has LESS travel than the 3PH, and you will be able to lift even MORE than the 3PH is rated for at the ball ends. And if you seet it up where the hook moves more, you will have less lift capacity.

BUT...with a PHD type without a separate TL, ANY point behind 3PH pivot is moving MORE than the 3PH ends, thus MORE range of travel but LESS lift capacity.
 
   / Boom pole and top link #20  
Just thought I'd throw this in on a side note. I had a neighbor (passed away several years ago) that was using a boom pole without the top link and the pin that connects the pole to the top link connection broke. The pole came up and then moved forward pinning him against the steering wheel. He was lucky to just have some bruising and was very sore for about a week. Could have been much worse. So be careful and make sure the pins are secure and in good condition.
 
 
 
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