Zip line cable used to pull supplies up mtn....

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    Cable Line Pull
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Discussion Overview

The discussion revolves around the feasibility and requirements for using a zip line cable to pull supplies up a mountain, specifically focusing on the necessary cable specifications, pulley systems, and winch requirements for a load of 1000 lbs over a significant elevation change and horizontal distance.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant inquires about the minimum type and size of cable required to support a 1000 lb load, considering a vertical elevation change of 1,000 feet and a horizontal distance of 1,800 feet.
  • Another participant suggests starting with a diagram to assist in calculations and emphasizes the importance of connecting the pull rope below the suspension cable to avoid tangling.
  • A participant notes that the minimum strength required for the cable is determined when it is vertical, but the force increases as the cable approaches a horizontal position.
  • One participant expresses the need to minimize sag in the cable while ensuring that the load does not touch the ground, mentioning the use of a pickup truck winch to achieve this.
  • There is a request for information on the smallest or cheapest electric or small engine-powered winch capable of lifting at least 1000 lbs and accommodating a drum for 2,000 feet of 1/4" cable.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the specific requirements for the cable, winch, or pulley system, and multiple viewpoints regarding the setup and calculations remain present.

Contextual Notes

Participants have not yet established the height of the supporting posts or the exact sag of the cable, which are critical factors in determining the cable specifications and winch requirements.

shane2
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If even feasible, what minimum type/size cable reqd with trolly attached that would have maximum 1000 lb load suspended from it, that would be pulled up, from atop, by second separate free line for the following location; 1,000 foot elevation change to where base anchor point was, horizontally, 1,800 feet distant, looking straight down over it? Before cable sag and stretch is taken into account, the length of cable appears to need to be about 2,060 feet long. Also, what minimum strength pull rope would be required for 1000 lbs, if trolley was typical, friction-wise? Also, any clue to what minimum size motor or engine would likely be reqd on drum to pull 1000 lbs via that free line? Thank you, in advance, for any insights.
 
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You should start by drawing a diagram of this. Then we can help you do the calculations. Also, the pull rope needs to be connected below, not above, to avoid rubbing against or tangling with the suspension cable and trolley.
 
OK, rough sketch here...
drawing.jpg
 
Great start.

Now, the minimum strength required by a cable supporting an object comes from when the cable is vertical. Then it only supports their combined weights. The closer to horizontal or straight you try to make the cable (the less it sags), the higher the force. So: how much can it sag without hitting the ground?
 
russ_watters said:
So: how much can it sag without hitting the ground?

Let's assume as little slack or sag as reasonably achievable, so that the restraining posts at each end are as short as possible, but still high enough to have load off the ground, and not dragging, at either or both ends. When I say 'reasonably achievable', the best I'll be able to do, after top of cable secured, is have a pickup truck winch at bottom end slowly pull and make cable more taut before securing it.

I won't be able to figure out, yet, just how high those posts will need to be. I've got to take into account the height of load and connecting straps up to the trolley at cable (guessing now about 6-8') and also how much we figure out that whatever chosen cable will likely be sagging below a straight line.
 
Last edited:
I'm also needing to find smallest/cheapest electric or small engine powered winch that'll safely lift, at least, 1000lbs, and has a drum that'll accept 2,000' of 1/4" cable.
 

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