Square Thread  Torque Required to Raise Load Formula & Calculator
 

Torque required to raise load calculator  step by step calculation, formula & solved example problem to find the torque required during raising the load by using the square thread (power screw) in power transmission. Load in Newton F, mean diameter d_{m}, mean collar diameter d_{c}, square thread pitch distance l, coefficient of friction for thread μ & coefficient of friction for collar &mu_{c} are the key terms of this calculation.
Formula
In mechanical engineering, the below mathematical formula is used to calculate the minimum torque required to raise load (T_{R}) for square thread power transmission.
Solved Example
The below step by step solved example problem may helpful for users to understand how the input values are being used in such calculations to calculate the torque required to raise the load or horizontally move against the force using the square threaded screw (power screw) in power transmission.
Example Problem
A vice using the square thread having the nominal screw diameter d = 12 mm, pitch width p = l = 2.5 mm, square thread frictional coefficient μ = 0.25, coefficient of friction for collar &mu_{c} = 0.25, mean diameter d_{m} = 10 mm, mean collar diameter d_{c} = 18 mm & the capacity of the vice clamp is 900 Newton. Calculate the torque required to tighten the vice clamp to its full capacity.
Solution
The given data
load in Newton F = 900 N
mean diameter d_{m} = 10 mm
mean collar diameter d_{c} = 18 mm
square thread pitch distance l = 2.5 mm
coefficient of friction for thread μ = 0.25
coefficient of friction for collar &mu_{c} = 0.25
Step by step calculation
Formula to find T_{R} = {[(F x d_{m})/2] x [l + (π x μ x d_{m})]/[(π x d_{m})  (μ x l)] + [(F x μ_{c} x d_{c})/2]}
If only nominal diameter & pitch of power screw given
mean diameter d_{m} = d_{n}  (p/2)
substitute the values in the above formula
= [900 x 10/2] x [(2.5 + (π x 0.25 x 10))/((π x 10)  (0.25 x 2.5))]+ [(900 x 0.25 x 18)/2]
= 3.53 Nmm
T_{R} = 3.53 Nmm
divide it by 1000 to convert it Nmm to Nm
T_{R} = 3.53/1000
T_{R} = 0.0353 Nm
In the field of power transmission by using square thread or power screw in mechanical engineering, it's important to analyse the torque requirement to move the load against the force. The above formula, step by step calculation & solved example problem may be useful for users to understand how the values are being used in the formula to find the minimum torque reuired to increase the load T_{R}, however, when it comes to online for quick calculations, this power screw torque required to raise the load calculator helps the user to perform & verify such mechanical engineering calculations as quick as possible.