[Robot360]

For multi-stage telescoping lift designs where the actuation motor actively drives the stages up and down, how are the actuation cables typically kept tensioned? I have searched throughout the forums and white papers, and have not seen much on specifically how the cables kept tensioned.

For instance, with a continuous-style telescoping lift design, the up-feed cable and down-feed cable should ideally feed in and out at the same rate, but since they wrap around drive pulleys, their effective feed rates will differ from each other as the lift extends/retracts since their pulley-wrap radius differs depending on how much cable is on each drive pulley (assuming the cable wraps onto itself). Thus, in that case, an active tensioner would be needed to take up the slack. A possible exception could be if the cables spiraled around the drive pulleys in a single layer (so the wrap radius remains constant), but in that case, is something done to ensure the single-layer spiral wrapping?

A similar cable-tensioning issue could potentially exist with cascade-style telescoping lift designs, too.

Are there schemes in place to ensure the cables always remained tensioned without an active tensioner?

For this thread, I am only referring to designs where one motor (or a group of coupled motors) drive all of the stages, not designs where each stage has its own motor.

I would appreciate your insight. Thanks!