proFeign
Cast Iron
- Joined
- Oct 2, 2007
- Location
- Santa Barbara, CA
Question for engineers/PEs etc in re: torque multiplying "ratchet" looking tools
McMaster and some other supplier offer (for no small $$ by the way) a thing that looks like a big/long 1/2" driveish ratchet with a slightly larger head on it and apparently a gear mechanism inside that multiplies torque. I have a BS in ME and while that sounds good on paper I wonder if it's possible in real life.
In other words torque in is reaction torque and it seems like the fastener torque will be applied to the handle, gear reduction or not, and the user will have to apply the same amount of torque to achieve equilibrium. If there's a tie down/bolt down point in the ratchet area that's a different thing but for statics if you take your control surface to be around the ratchet head with the fastener torque as your perimeter on one side and your input torque via the handle on the other side torque in = torque out regardless of gearing (?). I think this might be oversimplified as I know you'd be doing more work on the handle than the fastener if it's geared way down, but reaction torque still the same? Equations would be welcome, since it's probably going to take them to convince me that someone a lone person standing on the ground could generate more torque on a fastener than he is applying on the handle of a wrench, in spite of the lesser degree of rotation, respective to each part.
This is something that has bothered me since I first saw parts of this nature... If it works and I've overlooked something obvious that would be great but I figure without an anchor point for the gear reduction (like locking an orbital ring to a stationary piece of the part) I don't know how you'd get more torque into a fastener than your body's putting into a wrench even if you move the handle 100 degrees for every ten of output...
McMaster and some other supplier offer (for no small $$ by the way) a thing that looks like a big/long 1/2" driveish ratchet with a slightly larger head on it and apparently a gear mechanism inside that multiplies torque. I have a BS in ME and while that sounds good on paper I wonder if it's possible in real life.
In other words torque in is reaction torque and it seems like the fastener torque will be applied to the handle, gear reduction or not, and the user will have to apply the same amount of torque to achieve equilibrium. If there's a tie down/bolt down point in the ratchet area that's a different thing but for statics if you take your control surface to be around the ratchet head with the fastener torque as your perimeter on one side and your input torque via the handle on the other side torque in = torque out regardless of gearing (?). I think this might be oversimplified as I know you'd be doing more work on the handle than the fastener if it's geared way down, but reaction torque still the same? Equations would be welcome, since it's probably going to take them to convince me that someone a lone person standing on the ground could generate more torque on a fastener than he is applying on the handle of a wrench, in spite of the lesser degree of rotation, respective to each part.
This is something that has bothered me since I first saw parts of this nature... If it works and I've overlooked something obvious that would be great but I figure without an anchor point for the gear reduction (like locking an orbital ring to a stationary piece of the part) I don't know how you'd get more torque into a fastener than your body's putting into a wrench even if you move the handle 100 degrees for every ten of output...