Hi! Can anybody tell me please that if a human rotates some thing for example gear manually (by his hand), how high torque can it apply manually. i.e., what proportion of his weight or any thing else?

 

As far as I know that depends on the system that enables the rotation. I could be wrong but I think you need to be more specific if you want a better answer.

 

thanks for your interest. Actually i want to design a manually operated gear mechanism. this shall be driven by hand rotation of screw attached to pinion. I have to put some value of torque in solidedge spur gear designer.

 

The torque a person can produce depends on the length of the lever (crank) arm, whether the person is pushing or pulling, whether they're standing or seated, etc.

 

Exactly what Dana said. You need to work out your project before you start with modeling, and not the other way around.

 

Hello zubair

Average human hand can apply 100N force easily. so you can consider F=100N for your calculation.
and according to this force you can calculate Torque (T=F x R).

further this torque is also dependent on friction.

 

Way too many variables to consider in this example! Add a crank handle to the mechanism to eliminate some of them.

 

I read in machine design by Robert Norton that a human force can provide force upto 60 lbf

 

Check out this page:

http://www.roymech.co.uk/Useful_Tables/Human/Human_strength.html

The data on this page details the applied force (mean, range, standard deviation) for both females and males of a particular age range, for various loading scenarios (e.g. turning a circular knob, twisting a lid, etc)

If you review the related links at the bottom of the page you'll come across more detailed data covering different age ranges and more loading scenarios.

 

hi,,I have looked up.but only find the grip strength(about 350N). i guess that the torque depends on human's wrist force which should be smaller than grip strength(maybe it's 200N), hope helpful.