Monthly Archives: May 2012

How Post-war Bicycles are Made

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I thought this was a fantastic “how it’s made” video from post-war Britain.

Couple of highlights for me: (“Spoilers”, watch video first)

  • OH&S? What? A delightful lack of regard for safety in many many places;
    • Worker dipping hot bike frames into some kind of cleaning bath, vapour enveloping him… Facemask, or protective clothing? Nope.
    • All manner of spinning, pressing, other moving parts… no guards anywhere, just try not to lose a finger/eye/arm.
    • Worker dipping bike frames into an enamel paint bath all day, with his bare hands.
  • Amazing machinery… The gadget that cuts the teeth into the main gear? (nom nom nom) Or any of the forging/pressing stuff? Wow.
  • The bottom bracket of each bike is formed from a single circular piece of steel, pressed into a cylinder, then gradually into the very complex final shape.
  • No Bowden cables back then, if you look carefully during the assembly steps these bikes actually use a Rod Brake system, and presumably something similar for the gear changer.
  • Very similar to today’s bikes. I’m sure you could take any person from the video, put them on a 2012 carbon-fibre fancy-bike, and they’d have no trouble riding it around. Compare to today’s fancy cars, and even working out what to do with the key. ^_^

More folding bed linkage design

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I’ve refined the earlier linkage design, and managed to simulate it in Phun! (Unfortunately while being easy to use and great for doing simulations, it doesn’t really rate as a proper CAD package; lacking the concept of ‘measurement’ for a start)

Video

Another advantage of this design, I think, is that when the bed is open there’s no gap between the bed and the wall. Many folding beds have this gap, and need a panel anchored to the inner edge of the bed to protect the user rolling down into the mechanism.

A few other challenges have arisen in designing this bed. Namely;

  • How to fit a desk somewhere into the design, either that folds down with the bed (so as to end up flat on the floor) or that folds up out of the way before folding the bed down.
  • How to fit a wardrobe into the space. The metal bed frame I’m using is 1900 mm tall. The thin IKEA PAX wardrobe is 500 mm wide. The *entire* room is ~2400 mm wide. So maybe I’ll need to figure out how to narrow the wardrobe slightly.
  • How to get this all done before my sister-in-law comes to stay!