Woodwork guy trying to solve coffee problem

One of the few good things about the crisis is that my sons are staying with us, and I’m helping my middle son with his project of stripping out a transit van and refitting as a camper. Of course when and where he’ll ever be able to use a camper in coming years is a moot point ... but that’s by the by.

Now, what with him being a coffee nut, the fit-out absolutely has to include his pride and joy, his thumping great coffee machine and grinder. No matter that he has a total of 1200 x 550mm space for kitchen counter, of which coffee making will take up half; nor that the machines weigh about 50kg combined, and the coffee machine is over 750mm tall.

Well there is a solution, namely a lift: when down the coffee machine is stored below the work surface and the top of the lift is flush with the work surface, giving you a cooking prep area; when up the coffee machine is brought level with the work area. Basically this lift has to raise a platform roughly 500 x 500 up by 800, with the space below it being about 100 high. With the machines weighting 50kg, and making allowance for the weight of the structure and also downwards force from coffee tamping I think we should be allowing for 100kg.

It’s his birthday soon and I’d like to do this for him. I’m looking for a quality solution, not something horrible rickety and jerky. Now I’m reasonably practical and can work fairly precisely (eg cabinetry), but this is outside my experience.

What I’m envisaging is that the lift comprises a lower platform and an upper platform, both about 500mm square, and 800mm apart (top to top), held together say by threaded rod struts with 4 guide columns running through the corners. These could be full height (floor to ceiling) if desired but better if this can be avoided.

I’ve got three different ideas of how to drive it, which I throw out there to get the creative juices flowing ...
  1. 4 linear actuators with 800mm travel, one in each guide column; they’d have to be the type of actuator that can be sync’ed by being driven by a suitable controller.
  2. Rotating lead screws in each column (the column would have to be slotted), with a corresponding nut on each corner of the lift. The lead screws would have a cog either the top or the bottom, driven by a central gear to maintain synchronicity. The central gear could be driven direct by a motor, but if it was belt driven then the motor could be outside the lift space and then wouldn’t be constrained by height
  3. Build a scissor mechanism below the lift, driven by a small high force linear actuator.

DRawings and photos attached.IMG_20200409_115231.jpgIMG_20200409_115322.jpgIMG_20200409_115231.jpg

Any thoughts on this gratefully received!

That's quite an espresso set-up; I can understand why he enjoys his espresso so much!

I was envisioning something pushing up from the bottom; but that doesn't have to be the only solution. Something pulling from the top might also work. The problem with not having a geared mechanism to do the raising and lowering is the high possibility for misalignment.

Something which might work is a variable desktop mechanism. You could buy an inexpensive one (manual or electric) and re-purpose the mechanism to do the "heavy lifting." I'm thinking of a full desktop, not one of the smaller devices which sits on top of an existing desk and can be raised or lowered. THOUGH, I have one of those desktop versions which has a nifty gas-charged device (like the rear light-gates of many hatchback autos have!) for infinite adjustment of the desk height (it's not one with fixed detents). I also have a kit I bought, on which I could put my own preferred desktop on which can be electrically raised and lowered (using a 110/220 VAC power supply.... probably not the best idea in a caravan--but if he's using his espresso machine and grinder he probably has access to AC power!). Again, the full-size variable height desktops use a geared mechanism to keep both sides raising and lowering at the same rate, preventing misalignment. And, the total travel might be close to or exceed what you need for this application.

Whenever I have a need for something unique like this, I turn to my trusty McMaster-Carr catalogs. I still have paper copies around, and get one whenever I have the chance. But, they are on-line--though I find perusing the on-line version very difficult as it is "organized" in a fashion that usually doesn't make it conducive to browsing through. A paper copy of the catalog can be so easy to thumb through, and dog-ear pages to come back to.

Anyway, you're probably somewhere in Europe or the UK and they probably have something similar to McMaster-Carr (a US company). I have ordered from McMaster-Carr when working outside the US and paid the delivery charges--a small price for getting the perfect items which aren't always available in Borneo or Oman or Port Dickson or Jakarta.

Please let us know how this turns out. I have a similar espresso liking (bordering on a fetish, truth be told...), and can't carry my preferred machine in my caravan at the present time, and am thinking of some other modifications that might make something like this possible....