CAD or very clear explanation pls.
The cutaway on page 41 of https://wcproducts.info/files/frc/manuals/GreyT%20Telescope%20-%20User%20Guide.pdf kind of shows it.
Basically, a couple springs are up at the top of one stage with their end stretched out and attached to the bottom of next inner stage. These springs are constantly pulling up on that inner stage, trying to extend the arm. A rope or cable is attached to the innermost stage holding back the arm from extending, and is used to retract the arm.
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There is another way to mount the constant force springs, thay can also be mounted pulling the inner stage downwards. Both ways are good but each has its own advantages and disadvantages.
For example the configuration you showed uses the spring to generate the force upwards to pull the inner stage towards that direction but because of that extra force you would need to use more power with the engine and can cause the time it takes you to open/close your arm to reduce by a lot.
And on the other side there is the configuration using the springs to pull downwards. This can be better due to the direction of the force the spring generate. It would help the engine to pull the arm downwards and will reduce the time it takes the arm to move in the same direction.
But over all both configurations are good it depends only on what you and your team would chose. For example this year our team chose to use the configuration you suggested but i also saw teams using the configuration that uses the springs to pull downwards (like 5635).
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This video is a little long but it walks through the end to end fabrication & assembly of the Thrifty Telescoping Tube kit and should give you a better understanding of how the concept works:
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yeah intuitively I thought the CF springs were spooled at the bottom of the stage so it pulled down on the intermost stage, Thus keeping the telescoping climber in an fixed downward positions. and when forcefully unwinded it would force the mechanism to go up. I never thought from Christopher’s response that the CF spring was on top of the stage pulling another stage up which when thinking about makes sense.
PSA. When you have the springs on top pulling the arm up you are fighting gravity. If you fall over and the power is turned off (match end) gravity isn’t pulling on the lifter and this can result.
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