Design help required please - Automatic drawer raise/tilt.

[f1reshark]

Hey everyone,

I'm after some help and advice regarding a little project that I'm attempting. I'm sure that you experts can come up with some solutions to this. I'd be very grateful to all that can offer some input.

I want to automate a table drawer so that it opens to a certain point, stops, and then the small, inner hinged shelf raises to the table top level.


Here are some basic diagramsthat may display what I mean a little clearer:


Position 1 (Drawer closed)

The green arrows represent the movement that I need to automate


Position 2 (Drawer open and shelf raised)

The shelf will contain some mounted controlls - so not much weight at all.

I'm by no means an electronics expert, but I assume that a motor would do the trick. How exactly would that work/be connected up?

Supply voltage would be 12V


I'm open to all ideas...


Many thanks

f1reshark

[panjabi_j4tt]

You could maybe use an actuator to get the draw to come out but not too sure about the shelf, maybe some kind of spring loaded system but that idea would mean manually pushing the shelf back down. Could use two actuators one for pushing the draw out and one for raising the shelf. Sorry but my knowledge on actuators isn't great but a friend uses one to make his tv rise out of a cupboard.

[davehk]

you could raise the shelf using dowels each side running in a channel in the drawer sides that follows an appropriate contour - no need for springs. That would automatically raise and lower the shelf as the drawer goes out and in.

So all you need is the actuator to operate the drawer, a couple of microswitches for limit stops, and a couple of push buttons or a screen control switch. If you want to be able to just push the switch momentarily add a couple of relays.

No electronics needed as such - it's just like an electric screen

[f1reshark]

Thanks to you both so far for your kind replies and information.

DaveHK, can you elaborate on your dowels theory for me - sounds interesting.

By dowels, do you mean the wooden peg type? How exactly would that work?


Thanks again

[davehk]

OK, so your platform is hinged as shown in your diagram. Cut out the inside of each side of the drawer so that it's just a frame - leaving a large rectangular hole (you're not going to store anything in here!)

Sink a stainless steel pin each side of the platform at the trailing end long enough to protrude right through the hole you cut in the drawer side and into the carcass.

Rout a channel in each side of the carcass that the pins will ride in, with a suitable contour to raise the platform as the drawer opens. You'll find that the pin actually needs to be in a block attached underneath the drawer to get sufficient lift. The trailing end of the platform will need to be chamfered if you want it to be flush with the top of the carcass when raised.

Dismantle an old VHS recorder and look at the mechanism for loading/unloading tape and you'll get the idea.

[f1reshark]

One word DaveHK:

Genius!


Thanks for the suggestion and I know it'll work.


Cheers again.

[davehk]

You won't actually have to cut out much of the drawer sides - just the arc traced by the pins as the plaform moves.

Candle wax is good for lubricating the channels the pins run in.

Let us know how it turns out - with piccies - or better still a video clip of it working.