# Help With Design

• posted
Hi,
Here's the situation:
I need to move a fibreglass plate out the way using only one piston. The
plate will be about 200mm by 100mm, 5mm thick. The plate has to drop down,
then slide under the surrounding fibreglass leaving a hole open. It can
only use one double acting ram though, and it must be reversible so the
plate can be put back in postion.
Here's a diagram:
can do it with two, but I'd really prefer to do it with just one ram. Can
it be done?
Michael
• posted
If your plate were to have chamfered edges, then the initial drop down could be a diagonal movement, and the whole requirement could be achieved by a peg underneath the plate and to the side of it running in a groove that defines the desired trajectory.
Failing that, what is the mecahnism used on sliding doors seen on the side of some modern vehicles? AIUI, you impart a horizontal force only, and the door lifts out of the hole and then slide open.
Michael wrote:
• posted
Thanks Polymath, however I don't have enough space around, to allow for the chamfered method.
The sliding door method would work, but I will have to build it slightly different, as the door has to slid on the inside not the outside. I will consider this though. Thanks
• posted
I have an idea that may work, but of course it all depends how much space you have to play with and what you fix things to.
If you can fix a clevis in the centre of the plate that is the first step. You then need to make an L shaped angle bracket, one end of which would pivot in the clevis and the other pivoting around the cylinder end. This would have to be designed so that in the closed position the arms are normally inclined by around 15 degrees away from horozontal and vertical.
In the right angled corner of the bracket you need another pivot hole into which a pin is fixed and not allowed to rotate relative to the bracket. The pin, say for example 8mm dia, would then have 2 flat faces ground onto it, parallel to each other and also parallel to the topmost inclined arm, i.e. so they are all at 15 degrees, with say a size of around 6mm.
This fixed pin then needs to pivot in a matching diameter on another bracket on the same centreline as the pin. Coming off the centreline of the pivot hole you would then machine a 6mm wide horizontal slot( or parallel to the cylinder travel) to match the required length of travel on the cylinder.
The theory is that when the cylinder first starts to move it will pull one arm of the L bracket which will rotate the arm pulling the plate downwards, and also rotate the fixed pin in its matching hole until the point where the flats on the pin align with the slot machined in the second bracket,whereupon the whole assembly should be pulled along by the cylinder and guided by the flats in the slot. Returning to the orignal position should just be a case of reversing the piston travel. You would also need a little bit of vertical guidance but I'm sure you could work that bit out.
Should work I *think*, unless of course some of the better minds on here can see a problem I haven't thought of. It would probably need lowish pressure and slow speed.
Peter
• posted
Hmm, maybe do ist this way?

(Drawing this tokk longer than thinking it, so there may be some = errors...)
Another Michael. ;-)
• posted
Thanks Michael,
That drawing puts mine to shame :-)
Wow, the list is growing, I havn't got much time at the moment, but tonight should have lots. I will then evaluate all the designs and publish the chosen one on here later tonight. I will start on the piston tomorrow.
Peter, as I've already said I havn't much time, so havn't been able to read yours yet.
Any more designs just publish them and I'll get around to them tonight
Thanks for all the replys,
Michael
• posted
Michael, the other Michael & I are thinking along exactly the same lines but with different approachs. My idea is simpler but his is possibly a bit more secure. However, realising that my explanation hasn't quite done the trick and a picture is worth a thousand words as they say, have a look here
Regards
Peter
• posted
Hi!
To put Honor where the Wisdom is: The Idea to use a "flattened cylinder" to stop the rotation of the L-Shape ist great and will save him from=20 milling/sawing the curved glide-path in my idea.
maybe make "Best of both worlds" an use Your Idea together wiht my = approach of 2 (4) fixing points to the plate?
At first, I thougt to mount 2 of my glide-plates on each side of the = glass plate, one of them mirrored, so that the Ram can connect to a bar in the = Middle, and the opened hole is fully accessible, with no bars in the Middle...
Michael.
• posted
Thanks Peter, I can clearly see now what you mean. And again, another drawing to put mine to shame. :-) What do you guys use for them?
I think now I will go with Michael's idea. This is due mainly to the fact that the guides can be postioned at the side and won't block the opening like they do slightly on yours.
So now I have now excuse to not start making it....
Thanks Again,
Michael
• posted
"I Don't know what peter would reccomend..."
;-)
but I use Corel Draw 8.
Sometimes a "Pain in the ass", especially if You need to do 3D, but I know it since verson 4, so I can do mostly without looking in the Manual.
Michael.
P.S.:Sorry for my sometimes bad english, I'm a german Native...=20
• posted
Hi Peter, a very good design. What did you use for the drawing? I use Adobe PS CS & I never manage to get that standard of lovely curve shading that you managed on the cylinders. Did you use a filter? -- Dave Croft Warrington
• posted
I can't take credit for the curve shading I'm afraid, it was all done by the program. I drew it up in Solidworks as a 3D solid assembly model and the standard lighting settings did the effects.. It did mean I could check the idea worked though using the mates & simulation feature to move it, then I just moved it to different positions and saved it as a picture. If I'd learned how to work the animation plug-in in the last 5 years it could have had the full bells and whistles treatment:)
Peter

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