Questioning Lift Angle

[Doofy]

Any Mechanical Engineers or Math Wizards here to answer a question? I rebuilt my Snowplow A-Frame and made it one foot longer than it was, hoping to get a better angle. Question: Is the Lift chain at to great of an angle to the pump? Would a straighter lift, say to the center cross brace be less stress? Thanks for any insight.

 

[zzvyb6]

Stress, as in internal forces and moments constrained within a material will be higher but probably well within the yield (strain) boundary of the metal. What you've lost is the displacement range (won't lift as high because of angle). So, put another eyebolt and the central crossmember and get it back Stress ought to be just fine.

The problem you face withe the extra length is steering. Any side-force on the plow times the increased moment arm distance means it must be counteracted by the front AND rear tires. If nothing there changes, you will have a harder time driving straight (or more correctly going where you want to go.)

 

[ruffdog]

Any Mechanical Engineers or Math Wizards here to answer a question? I rebuilt my Snowplow A-Frame and made it one foot longer than it was, hoping to get a better angle. Question: Is the Lift chain at to great of an angle to the pump? Would a straighter lift, say to the center cross brace be less stress? Thanks for any insight.
View attachment 672775View attachment 672776

Yeah, I would try it at the center cross brace as it is more of a straight pull for the lift arm. Yes, your plow is further out front and will take more pressure to lift it but it should do fine. It wouldn't take much to do a simple test.

 

[Doofy]

Stress, as in internal forces and moments constrained within a material will be higher but probably well within the yield (strain) boundary of the metal. What you've lost is the displacement range (won't lift as high because of angle). So, put another eyebolt and the central crossmember and get it back Stress ought to be just fine.

The problem you face withe the extra length is steering. Any side-force on the plow times the increased moment arm distance means it must be counteracted by the front AND rear tires. If nothing there changes, you will have a harder time driving straight (or more correctly going where you want to go.)

Thank You for the insight. That Beast goes where you point it. F-350 Crew Cab Diesel with chains on the rear. Only problem is that the overall length is 27'-6". Glad I just do mine and a couple of neighbors and no real congested areas to plow.

Would there be any advantage to tying the front chain to the middle chain for the Lift? I would increase my blade lift some and also take some of the stress off of were the blade mounts. This is a Straight Push only, no angling.

 

[MF RED in MT]

Maybe you could extend the tube steel at where the top of your chain connects to regain your original lifting angle.

KC

 

[LD1]

Why was the A-arm lengthened?
Moving the chain back would mean less stress on the chain and higher lifting height, but the pump might not lift it. Those meyer pumps are rated to lift the plow as designed and not much more. get some snow built up and packed on the blade and they struggle.

Just off the cuff, by moving the chain point back you will need roughly twice the hydraulic force to lift the plow....which I think it will struggle if it will do it at all.

And your a-frame angle is less than desirable. I hope you never plan on angling that plow, cause I dont think you will like what you see

 

[RoyKing]

You are going to get less lift, and you have increased the load. To get the lift back you need to extend the lift arm, but that will also increase lift load, but that pump looks healthy.

 

[Doofy]

You are going to get less lift, and you have increased the load. To get the lift back you need to extend the lift arm, but that will also increase lift load, but that pump looks healthy.

That is an old Meyer T-6 pump from the 60s. Slow and loud but it gets the job done. I think I have 5 or 6 of these for spares. I did burn up one motor about 15 years ago. Not sure what the rated lift is for this pump but the plow is very heavy.

 

[Doofy]

Why was the A-arm lengthened?
Moving the chain back would mean less stress on the chain and higher lifting height, but the pump might not lift it. Those meyer pumps are rated to lift the plow as designed and not much more. get some snow built up and packed on the blade and they struggle.

Just off the cuff, by moving the chain point back you will need roughly twice the hydraulic force to lift the plow....which I think it will struggle if it will do it at all.

And your a-frame angle is less than desirable. I hope you never plan on angling that plow, cause I dont think you will like what you see

The mount points on the truck are to high and the angle was to sharp with the shorter A-Frame. The trip springs had to be tightened to the max to get the plow flat to the ground.

The welds broke on the cross support of the old A-Frame and I managed to twist everything in to a pretzel. The only thing salvageable was the front chain point and rear truck mount point. With the a-Frame 12" longer, I can loosen the trip springs up some and still have the plow sit flat.

 

[Doofy]

This plow is a Hodge-Podge of Meyer and Western and is for straight plowing only, no angle. We are ready for snow so I should know in the next week or two how it does and if I need to make more changes.