Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: airman00 on August 31, 2007, 05:09:21 PM
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I need to know the amount of torque needed to twist off a bottle cap from a soda bottle. Can anyone guess an approximate torque? Or where I can find that out from?
Thank you,
Eric
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securly mount a 1ft long rod to teh cap. and lay the bottle down, with teh cap hanging off of a table, and then start adding weights at the end of the rod.
once it twists off, you know how many ft/lb you need
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securly mount a 1ft long rod to teh cap. and lay the bottle down, with teh cap hanging off of a table, and then start adding weights at the end of the rod.
once it twists off, you know how many ft/lb you need
Account for the torque provided by the rod too, of course.
Unless you mount the center of the rod to the cap, then it cancels itself out.
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securly mount a 1ft long rod to teh cap. and lay the bottle down, with teh cap hanging off of a table, and then start adding weights at the end of the rod.
once it twists off, you know how many ft/lb you need
Account for the torque provided by the rod too, of course.
Unless you mount the center of the rod to the cap, then it cancels itself out.
yeah didn't think of that.
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Account for the torque provided by the rod too, of course.
FYI, its:
torque = .5 * (weight of rod) * (length of rod) + (weight of object) * (length of rod)
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Account for the torque provided by the rod too, of course.
FYI, its:
torque = .5 * (weight of rod) * (length of rod) + (weight of object) * (length of rod)
I *always* been confused on that:
Torque= rF (disntace * force)
Weight is a force, but to calc weight dont u have to say W = mg (mass and grav. acc. 9.8m/s^2)!?!?
So if u mass it on a scale thats the mass right?? so u have to multiply it dont u?
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Wrong, you can scale only the weight, not the mass. Then you can calculate the mass using the formula you mentioned.
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Weight is mass times gravity.
Weight is a force, while mass is not.
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securly mount a 1ft long rod to teh cap. and lay the bottle down, with teh cap hanging off of a table, and then start adding weights at the end of the rod.
once it twists off, you know how many ft/lb you need
Account for the torque provided by the rod too, of course.
Unless you mount the center of the rod to the cap, then it cancels itself out.
Unless he uses one of those mass-less rods! ;D
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Couldnt he just use a torque wrench,just find a way to fit the cap in there.
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when calculating the torque the direction is also important.
T=rf is wrong
Correct
T=RxF (cross product)
=R*F*sin(angle) (absolute value)
=det [i j k ]
[Fx Fy Fz]
[Rx Ry Ry]
where det is the determinant of the matrix.
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Couldnt he just use a torque wrench,just find a way to fit the cap in there.
AFAIK torgue wrenches are made for high amounts of toruqe
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..not to be mean or anything..
BUT:
Just use a big servo and call it a day. Its going to be less then friction that human skin can withtake.. as such, its not going to be a lot.
my guess is under 40ft/lbs.
Probaly far under.
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my guess is under 40ft/lbs.
I think you meant 40lb*ft ;D
btw, thats a lot!
Im guessing more like 5lbft . . .
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ya I did mean that lol thanks Admin.
I agree its also FAR under 40, 40 would probaly shatter the glass while trying to twist.. lol