What Torque is Needed for a Hydraulic Motor to Lift a 10 lb Box 20 Feet?

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Discussion Overview

The discussion revolves around calculating the torque required for a hydraulic motor to lift a 10 lb box 20 feet using a chain and sprocket system. Participants explore the mechanics involved, including the dimensions of the sprocket and the weight of the chain, while disregarding friction.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant outlines the setup involving a 10 lb box, a 6” diameter sprocket, and a chain, seeking to determine the necessary torque for the hydraulic motor.
  • Another participant suggests the use of a counter-weight on the opposite side of the loop to assist in lifting the box.
  • A participant expresses confusion about the scenario involving anchors, questioning the practicality of having one anchor at each end of the chain and suggesting a diagram for clarity.
  • Calculations for torque are presented, converting units and providing both imperial and metric results, but the context of the setup remains debated.
  • One participant indicates a shift in approach, considering using a 12VDC motor instead of a hydraulic motor for cost reasons.

Areas of Agreement / Disagreement

Participants express differing views on the setup and mechanics of the system, particularly regarding the role of anchors and the practicality of the proposed solution. No consensus is reached on the best approach or the calculations presented.

Contextual Notes

There are unresolved assumptions regarding the setup, particularly the role of the anchors and the implications of using a hydraulic versus a DC motor. The calculations provided depend on specific interpretations of the system's mechanics.

dakotahm88
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TL;DR
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.
 
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dakotahm88 said:
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.
 
Could you attach a 10-lb weight at the opposite side of the loop, as a counter-weight?
 
Not in this particular scenario
 
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.
 
dakotahm88 said:
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
 
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Baluncore said:
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.
 
Do you now know the answer, or what question you should have asked, and what information is required?
 
  • #10
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.
 
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