pic: Inside the torque multiplier

[Richard Wallace]

Originally Posted by Conor Ryan

It multiplies the torque, by dividing the revolutions per minute. Since the power output cannot be greater than the power input.

Basically, its a gear reduction.

This is useful

Thanks for that link, Conor. The handtorque multiplier example shown there is an industrial grade unit with an epicyclic gear set.

The low-cost (read: Harbor Freight) unit does not have a conventional epicyclic gear set. It appears to operate differently. The input gear center hole pilots on an eccentric section of the input shaft, causing its tooth engagement point on the outer ring to revolve. The input gear revolves 33 times for every single revolution of the output gear, and both gears react against the teeth of the stationary ring. And as mentioned earlier, the gears are loosely pinned together in six places, allowing relative freedom of movement between the gears of about one tooth pitch. Also, the output gear rotation is opposite that of the input gear. So to loosen a lug nut you turn the crank clockwise. Maybe this really is a kind of epicyclic gear set, with the sun gear replaced by an eccentric -- sort of like a gear with one tooth?

I'm hoping someone with more experience in gear set design will jump in here an enlighten us to the mystery of this gear system. I am actually an electrical engineer, with just enough knowledge of mechanisms to be dangerous.