[robbmorganf]

I love this idea, particularly empowering people to move without feeling like they need electrical assistance.

If this is to become a widespread product, I think it needs to address two linked issues: (a) the product appears to be tuned to the specific weight of an individual, so that the counterweights/springs are neutral in use. Changing between individuals (or changing weight should the individual gain/lose weight) should be easy to do and hopefully transparent. (b) the product can't be accessed if it is on a different floor. Without the weight of a user, if unlocked, it would skyrocket upwards. I don't want to lock into the paradigms of an elevator, but the user needs to be able to access the product even if another user moved it.

Unfortunately, the only thought I have to solve these issues is to electrify it, or perhaps a clever hydraulic system. In any case, I think with batteries, it need not consume power from the grid.

[toss1]

While electric or hydraulic would be the easy way to make it move on its own when it's on the wrong floor, but not the only way. I'm sure that a system with a rope, pulley, and latching could be used to move it up or down just fine, albeit a bit more slowly. For moving from the higher to the lower level, one could design a setup so it just ratchets itself down with gravity, just clicking down a few cm at a time instead of just releasing and falling down, and this could also serve as a bit of a safe/speedy descent mode if the user can't do the whole motion one day. For ascending, just releasing the catch and pulling up on a pully/winch with a ratcheting mechanism would get it up there fine.

I really like these designers' ethos of not using electricity, and it'd be best to keep that intact as capabilities are added.

[robbmorganf]

I think it currently stores energy in a spring, hence helping the user go up and recovering energy on the way down.

I was just suggesting that if the energy can be stored in a battery or hydraulic accumulator, it's easier to change the "counterweight" force. In both cases, I think it can be done without any net assistance from the electrical grid.