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  • Who faced the ill-conceived design?

    Discussion in 'The main mechanical design forum' started by GoodCat, Jan 15, 2019.

    1. GoodCat

      GoodCat Well-Known Member EngineeringClicks Expert

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      Hello to all!
      I often I see frankly stupid decisions in the design of machines.
      How engineers dont consider the mechanic during plant design. They might design some configurations of machines in a way that the mechanics hands cant fit easily to repair.
      I want to note that the design of 70-80 years looks much better than the modern.
      What silly design have you come across?
       
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    3. MSHOfficial

      MSHOfficial Well-Known Member EngineeringClicks Expert

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      Well somethings are just horribly squeezed into. Like the CFM56-5B aircraft engine. Used by A320 family and Boeing 737 family. That engine was not made to be able to do anything by hand. All the engine piping work inside the covers need special rotating tools to operate with. Even screwing in screws need special longer, thinner screw drivers than the ones technicians have.
       
    4. john12

      john12 Well-Known Member EngineeringClicks Expert

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      Yeah, I've worked on some old car drum brakes that were so difficult to refit. I had to get a friend to help me out, and then I basically had to stand immediately in front of him, with him with his arms around me whilst we tried to hold the four different areas at once. My girlfriend at the time was starting to get a little jealous of how close we were!
       
    5. MSHOfficial

      MSHOfficial Well-Known Member EngineeringClicks Expert

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      HAHAHA. That was hilarious John.

      I once drove a Chevrolet, it was a huge car. Very spacious on the inside, huge trunk. However, everything other than that was squeezed into the car. Once we had to open up the radio and the multiple CD drive, and the connector plugs were really easy to open as we just had to pull them out. But when we were trying to get it back in, it was a disaster. Imagine putting a 2mm x 2mm x 6mm jack, and we are trying to put it into a 3mm x 3mm x 20 mm holder.

      We tried for a couple of hours, we did not have any tool that was small enough to fit in with that jack holder and also not damage the wire on the way out. We finally gave up and found a mechanic to do so, it took him a couple of hours too, to get the work done.

      But unlike us, he actually did it in the end, charged us about 100 USD to get 8 of those plugs in on both sides. Worst design I have ever seen, why would we need to put the pins in so deep and in such a restricted space. I never found the answer. I wonder if anyone else knows!
       
    6. tmark938

      tmark938 Moderator EngineeringClicks Expert

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      Along the same lines - car headlights!

      In the past I have tried on numerous occassions to change my own car headlight bulbs but I gave in. My hands were cut and scratched (maybe my fat fingers didnt help lol) and I now take it to the garage. However, it evens takes a good mechanic at least 20 minutes to replace a simple headlight. The cap and the bulb itself are squashed into the corner and its difficult to disconnect and then reconnect.

      Now, tell me, who designs this kind of stuff and why make it so difficult?
       
    7. john12

      john12 Well-Known Member EngineeringClicks Expert

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      Yeah, this is a big issue mechanics face I think - you never know when an 'easy job' will actually turn out to be a nightmare. I suppose they get more experienced at giving estimates (actually, I do the same in product design - I've underestimated jobs so many times in the past, but now I'm much better!).

      I don't know why cars are especially bad for this sort of thing. Perhaps it's because different teams design different sections (one does the dashboard, one does the headlights etc.) so when all of the elements get put together they don't work well together?

      This actually got me thinking about another example - I once took a ride in an old Soviet armoured personnel carrier and the ergonomics inside were terrible. I understand that it's an old design and that they're designed more more robustness than comfort... but there were sharp things sticking out everywhere - brackets and things like that.
      Surely if you're racing along over rough terrain you don't want these kind of things sticking out where people can smash into them by mistake.

      There were also loads of levers and other parts sticking up near the exit doors - not ideal if soldiers are jumping out in a hurry, with backpacks and webbing straps on - loads of stuff to get snagged on!
       

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