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Simple structure en...
 

[Closed] Simple structure engineering maths check..

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do what everyone else does, stick a palette on a forklift truck.


 
Posted : 15/08/2013 4:54 pm
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It would have to be a very small forklift...


 
Posted : 15/08/2013 4:56 pm
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Is the fat guy on a conveyor belt ?


 
Posted : 15/08/2013 5:07 pm
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[url= http://www.udesignconfigurable.com/29-supported-cantilever-rolling-ladder.html ]This thing might inspire you - but look how substantial it has to be for a rating of 226 kg![/url]


 
Posted : 15/08/2013 5:24 pm
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Have you considered the WaH Regs?
Maximum permissible user weight for any Cat 3 PPE is 136kg/21.5S so that rules out you 200kgs straight away.


 
Posted : 15/08/2013 5:34 pm
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[b]gofasterstripes[/b], I suggest you change your design to make the inclined strut vertical, right to the top beam, like the link [b]slunk [/b]gave, then you tell your bosses "This is a [i]concept[/i], to be worked up by qualified engineers - there's a lot of legislation to be complied with and I don't have the qualifications or experience to produce a certifiable design for this kind of device". [apologies if I'm running down your skills but from what you've posted that does appear to be the case]. It takes 7 years minimum to be a CEng. They will be putting themselves at risk if they rely on your design, even if it's tested. They'll be putting you at risk as well but they have the legal responsibility and are at greater risk.


 
Posted : 15/08/2013 6:08 pm
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Hi guys.

I think i will do as Greyboard says. TBH a disclaimer was in the plan from the start*, and I have kept and dated my calcs to show I have used all the care I can, but as you have rightly pointed out my engineering maths is pretty pants for some reason [IDK - I excelled at all my coursework and Maths for engineering exams, but I haven't used it in a year and a half and with no-one here doing anything similar I seem to have brain-rot].

Thanks for all your help, and I take comfort that there's nothing like this on the market, so either we've had a unique idea or it's damn hard to make such a device.

I have done only 2 years of an undergraduate Product Design course, and it would seem there's a reason for the other 5 years required for CEng status, eh?

I do feel disappointed that I haven't been able to get this sorted from the structural point of view, but I guess I just need to up my game significantly before I can handle this sort of calculation. Esp as I was 69.4% average last year and I want a 1st, dammit 🙂

Hope you all have a lovely evening and no badly engineered platforms collapse under you 😉

*Not that I thought I'd get it this wrong, but I realise my boss is rather want to rush into things, and I don't want someone's injury on my hands because they didn't check what certs this would need.

EDIT: Yeah I've got a copy of the WAH, but we've got a very fat** engineer and I really wanted him to be able to use it [i]if[/i] there's a way he can legitimately, I was going to let the legal bods look into that.

**He is also a lovely guy, just bloody huge!


 
Posted : 15/08/2013 6:45 pm
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Nah. Don't be hard on yourself. With the constraints you've worked with you have done very well, imo.

As you say, there's a reason there's nothing similar out there.

Do as greybeard says and explain what you've done and what you think the next steps should be. Back it up with some e-mails.

FWIW, we used an experienced precision, automated systems manufacturer to develop us an automated flush rig that had to handle IPA. They developed and manufactured the whole thing and then found that there were loads of standards relating to IPA. They had to redesign the wholewhole thing again and have it re-manufactured.
And this is a team of engineers who have made some bloody impressive kit. They just dropped the ball on this one


 
Posted : 15/08/2013 7:32 pm
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have you looked at aircraft ladders or boarding equipment, there might be some ideas there for you 😉


 
Posted : 15/08/2013 8:31 pm
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Hey, compositepro, could you engineer it if it was carbon fibre? I bet that it would suit the application - light and stiff!


 
Posted : 15/08/2013 8:59 pm
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you can buy carbon ladders for boats i think you can pull this off easily with aluminium


 
Posted : 15/08/2013 9:30 pm
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OK, ta.


 
Posted : 15/08/2013 10:49 pm
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30kg and to take 200kg or even 136kg for that reach. Ain't gonna happen.
Stick some sinkable/sprung loaded wheels on it and bugger the 30kg bit


 
Posted : 15/08/2013 11:52 pm
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If your asking people to carry it too, you need to consider manual handling regs maybe? It used to be around 25kg per person


 
Posted : 16/08/2013 6:34 am
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Oh wow, 'morning!

Yes, don't worry - I know. Currently the unit weighs around 28 and is handled in two separate parts.


 
Posted : 16/08/2013 7:05 am
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Whatever design you come up with, do a free body diagram form the complete frame first. This will give you the overall reaction loads to the applied load. You can then start to take the structure apart to calculate the internal loads. Each internal part should be in equilibrium so the sum of the vertical and horizontal forces should equal zero as well as the moments on each part.


 
Posted : 16/08/2013 11:26 am
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