If you’re a mechanical engineering wonk, you might appreciate this latest video from [Henry Segerman] wherein he demonstrates his various expanding racks.
[Henry] explains how the basic “double-rack” unit can be combined to make more complex structures. These structures are similar in spirit to the Hoberman sphere, which is a compact structure that can be expanded to fill a large space.
The double-rack units get a lot more interesting when you combine two or more of them. They each have rails that accommodate additional double-racks, holding the double-racks together. Because of how the gears from each double-rack are connected to the teeth of the others, expanding two double-racks causes all connected units to also expand.
Through the rest of the video, [Henry] shows you the marvelous myriad ways the basic structures can be combined to make remarkable expanding racks. He also explains some of the missteps and gotchas that his latest designs avoid based on his experience.
If you’re interested in such things, you might also like to check out Lathe Gears Make A Clock or Gear Up: A 15-Minute Intro On Involute Gears.
Do you have your own mechanical engineering hacks? Let us know on the tips line!
Neat exposition – these are commonly used on expandable tables and the like.
They are also used in high quality linear bearings. With regular drawer sliders, the ball cage usually creeps to one end or the other. With the high end version (such as used in prescicion grinding machinetools) the pinion in the center keeps the cage with the balls in the correct position.
The last bit reminded me of a book I once read. It was of a warehouse (I think it was 17x17x17 meter) that you could fold up and put in your pocket to take with you. Quite a neat trick. The biggest limitation was that you always had to fully unfold it before you could put anything in it or take it out. It was SF somewhere in the ’80-ies or ’90-ies, but I can’t recall the title.
It was called The_Advanced_Dungeons_and_Dragons_Players_Handbook published by TSR.
This seems like somethign that would be a good trick for a satellite engineer to keep up their sleeve.
Should have used a Penrose Triangle. That would fix the problem.