calculate the torque required

[sorinh]

I have a 60000lb loaa on the end of a 3" stem with a 3 threads per inch ,acme. this needs to be raised by rotating thre not on the other end being i nsde a gearbox. What's the torque required ? any help thanks.

 

[sorinh]

raised by a rotation NUT inside the gearbox

 

[sorinh]

more information:
I have calculated the torque in frictionless scenario got 265ft_lbs
Considering:
Acme thread: 2a is 29degrees
pitch is 1/3: 3threads per inch
coefficient of friction: for bronze nut and stainless steel stem, lubricated I have found value from 0.05 to 0.12. that result in value of the torque from 500ft_lbs to 1,150ft-lbs.
So what is more real value the 500ft_lbs (about twice the value of frictionless) or the 1,150ft_lbs (four times more the frictionless value) ?

 

[GregLocock]

0.05 seems to me to be a very low figure for a nut. Even 0.12 seems low to me.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[dvd]

For a stainless steel screw on a machine screw actuator, Duff-Norton lists efficiencies around 18%. It is not the same pitch as your screw, however, and Duff-Norton's load rating for a 3" screw is less than your 30 ton load. You will probably get a lot closer to the number by following their published numbers. Who made your components? Have you talked to them?

http://duffnorton.com/Public/18503/StainlessSteelMS.pdf

 

[sorinh]

dvd,
AUMA are furnishing the actuators.
as they are installed and miscomunication took placed between them and the manufactory of the stem, I have determined that we may have wrong actuator.
The miscommunication was generated by the fact that nominal torque is listen at 145o, then up to 10minutes for 950, 10 to 20 minutes to 670 and 20 to 30 minutes to 500.
SO what i know is the maximum force of 60000 to get this started.