Physics of a torque multiplier

[atikovi]

Found this video of a 78:1 version. Only $100 for something I never knew I wanted.

 

[nmantas]

Found this video of a 78:1 version. Only $100 for something I never knew I wanted.

Those go for $34 shipped on eBay (slightly different ratio): https://www.ebay.com/itm/382509263039

 

[atikovi]

Those go for $34 shipped on eBay (slightly different ratio): https://www.ebay.com/itm/382509263039

Damn that looks so tempting at that price.

 

[Jim c]

Gotta wonder about the quality and durability at that price. But it really does seem tempting.

 

[crane_guy]

Multiplying 100 by 3 is 300... That's why they advertise it as X4, because an input of 100 multiplied by 4 would be 400.

I understand what you are saying, but math only works one way. You just don't add your input into a multiplication equation. You are mixing addition and multiplication.

I think its confusion between ratios and multiplication that is messing it up. 3 to 1 and 4 to 1 are not the same as 3x1 and 4x1..

All that said, to the poster saying the drill is not a good example is wrong. It is exactly the same principle, same gear set type, in practice.

Drill motor is the input, attached to the case. This is the "wrench" on the above scenario. Always and only inputs 100 inlbs

Human hand is the static arm, immovable object in the scenario. Resists the full force applied by the multiplication effect.

Screw is the output. The nut in the scenario. Receives 400inlbs

Your hand(immovable) resists the full and equal force applied to the screw. You can change the drill gearing for a higher multiplied output by puting the drill in gear 2, thus multiplying the motors input through a planetary gear set, slowing the output and increasing the output forve, applying 400 to the screw. Your hand will then resist the full amount of output, whether its twice as much or more. The motor input(100inlbs) is the same no matter what happens.

It is a good example if you can envision these processes. It puts the force into your hand, instead of an adjacent lug nut.. For me, that makes it all come together in my mind. When the drill stalls, I can input just a hair more force with my hand, and turn the screw more.. So in effect, 100% of force is applied to both the immovable object and the output nut or screw. 100%, equals out to zero, balanced, whatever your wording.

Sent from my LGLS676 using Tapatalk

A 4:1 multiplier is referring to the gear ratio, not the actual torque. I know in the fist post, op mentioned removing all variables, but the variables can't be left out. It's a 4:1 gearbox, not 4:1 torque multiplier

 

[Citation]

A 4:1 multiplier is referring to the gear ratio, not the actual torque. I know in the fist post, op mentioned removing all variables, but the variables can't be left out. It's a 4:1 gearbox, not 4:1 torque multiplier

The torque ratio is 4:1 minus what ever the frictional loses are.