Sprocket torque question

[dakotahm88]

TL;DR Summary

Sprocket question

Need some help.
Trying to lift a 10 lb box 20 feet.
Hydraulic motor driven.
Bucket attached to chain anchors on each end of the chain.
6” diameter sprocket on top and bottom, the bottom sprocket will be driven by a hydraulic motor.

How much torque does the hydraulic motor need? Weight of chain let’s say is 25 lbs for this example. Disregard friction.

 

[dakotahm88]

TL;DR Summary: Sprocket question

Need some help.
Trying to lift a 10 lb box 20 feet.
Hydraulic motor driven.
Bucket attached to chain anchors on each end of the chain.
6” diameter sprocket on top and bottom, the bottom sprocket will be driven by a hydraulic motor.

How much torque does the hydraulic motor need? Weight of chain let’s say is 25 lbs for this example. Disregard friction.

Forgot to add, let’s say we’re moving 1 foot per second.

 

[Lnewqban]

Could you attach a 10-lb weight at the opposite side of the loop, as a counter-weight?

 

[dakotahm88]

Not in this particular scenario

 

[Baluncore]

The ships anchors, attached to both ends of the chain, will prevent the chain from moving. The hydrostatic pressure of the water, will be insufficient to drive the hydraulic motor, up the chain.
Maybe a diagram would help.

 

[Baluncore]

How much torque does the hydraulic motor need?

6" diameter = 3" radius ; 10 lb force.
Torque = 3" * 10 lb = 30 inch⋅pound = 2.5 ft⋅lb .

3" radius = 0.0762 m
10 lb = 4.536 kg
Force = 4.536 * 9.8 = 44.45 newton.
0.0762 * 44.45 = 3.387 N⋅m

 

[sophiecentaur]

The ships anchors, attached to both ends of the chain, will prevent the chain from moving.

I can't picture this on a "ship". One anchor up and one anchor down is not a useful scenario and wouldn't that be the case with one anchor at each end of a chain?
We do need a diagram because, in my mind, the two sides of the chain loop would balance.

 

[dakotahm88]

Nothing to do with a ship. lol. Here is a chain anchor. https://www.magnasourceinc.com/item...MIwaSn1_HYhwMVXhOtBh2ucAjzEAQYASABEgK66vD_BwE

 

[Baluncore]

Do you now know the answer, or what question you should have asked, and what information is required?

 

[dakotahm88]

yes I was calculating everything correctly, just didn’t seem realistic. I’m going to give it a go. I’ll post results! Probably going to use a 12VDC motor instead of hydraulic. Much cheaper to assemble.