OT Electric Domestic Oven Adaption

Hi, I am a member of a local voluntary group of mostly engineers who design and produce and donate specialist one-off mobility aids for the elderly and disabled. They have just been asked about modifications to a domestic, electrical oven - so they naturally passed it to the female electrical engineer in the group...

Basically, what is needed is for the two shelves of the oven to be capable of sliding out their full length, whilst supporting the weight of what may be a large turkey, without sagging and with nothing normally protruding beyond the normal mechanical envelope of the oven.

I can't think of what electrical engineer has to do with this - hence the OT - but any thoughts on solutions, no matter how off the wall, would be welcome. There are clearly some very bright cookies lurking around this group...

My present thought is to put wheels on the sliding trays and run them on tracks fitted into the oven and with extension tracks that can be clipped on by the user when the oven door is open. By mounting the front of the permanent track on an offset bracket, the load pushing it down and hence slightly forward would be translated by a lever into offsetting the rear track bracket, to move the rear of the track forward and slightly more lower. A small spring would pull it back to the normal position when unloaded. Thus, as the tray slides out so that its entire weight and leverage is applied to the front bracket, the rear bracket will pull the back of the rail lower - thus producing a slightly uphill gradient for the tray, which will get even more uphill the more weight on the tray. This should be enough to counter the bending (non-permament) of the extended rail with the applied weight.

Any alternative thoughts, or suggestions of more appropriate groups?

I had thought of using the ball-bearing heavy-weight drawer slides from surplus electronic equipment racks - but somehow don't think that they would cope with the conditions in a cooker..They do do wonders for drawers in kitchen cupboards though..

Many thanks,

Sue

Reply to
Palindr☻me
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My first thought. The ones I have for my drawers are all metal with metal ball bearings. A quick google and then some phone calls to the manufactures will get the answer. Heck they may even donate them for your cause. The total weight will determine the distance you can go. My drawer slides go 18 inches at 75 pounds total. A turkey has some serious center of gravity issues.

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Not the glitziest web page. You MUST have pdf enabled to see the pages. They are friendly and helpful. Yep also close to where I live. At least you will have something to look at and ponder until the phones work on Tuesday

You realize that the shelves will be come fixed vertically doing this. That in itself might be a deal breaker.

Reply to
SQLit

e

Thanks for that! I will see what they say - as you mention=20 they are friendly they may indeed be helpful rather than=20 just fall about laughing.

My present thought is to actually only fit one set of rails=20 at the very bottom of the cooker but provide a few different=20 height lift-off spacers (much as most microwave ovens are=20 supplied with) that can be placed over the bottom tray to=20 give multipe layers. It is a fan oven, so positioning within=20 the oven is not that much a factor.

Someone in another forum has suggested using an oven with an=20 open-down door and mounting the continuation rails in the=20 inside of the door - so that as the tray runs forward on its=20 rails, it can continue to run forward on rails on the door.=20 It seems a very simple and elegant solution - I wonder why=20 they don't fit them? It may need little drop-in bridging=20 pieces to join up the rails - but that should be trivial to=20 design and make.

--=20

Sue

Reply to
Palindr☻me

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Thanks for that! I will see what they say - as you mention they are friendly they may indeed be helpful rather than just fall about laughing.

My present thought is to actually only fit one set of rails at the very bottom of the cooker but provide a few different height lift-off spacers (much as most microwave ovens are supplied with) that can be placed over the bottom tray to give multipe layers. It is a fan oven, so positioning within the oven is not that much a factor.

Someone in another forum has suggested using an oven with an open-down door and mounting the continuation rails in the inside of the door - so that as the tray runs forward on its rails, it can continue to run forward on rails on the door. It seems a very simple and elegant solution - I wonder why they don't fit them? It may need little drop-in bridging pieces to join up the rails - but that should be trivial to design and make.

the door opens down the rails would have to be flexible, to change direction as the door goes from vertical to horizontal. or up you would end up with an slanted rail that would surely unload the "turkey" by gravity.

I really do not understand that concept at all.

Reply to
SQLit

You might ask the manufacturer. Don't tell them you plan to modify it as they will then stop talking to you, but ask if they have any kits to do what you want. I know that many US manufacturers offer Braille knobs or different handles for their appliances.

If that doesn't work, I think the drawer slides are your best option. Find some slides that don't have any plastic pieces, and clean out the grease (if any) with some not-too-nasty solvent like alcohol. You can use them dry, but there is grease that is made to be used on machines that process food. Talk to an oil company that supplies lubricants to industry, or perhaps go down to the local bakery, brewery, or meat-packing plant and offer to buy the maintenance guy lunch in exchange for a few grams of grease. A quick Google yields

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which looks like it might do what you want.

You might have to narrow the shelf a bit to get it to fit in between the slides.

Standard disclaimers apply; I don't get money from any of the companies mentioned above.

Matt Roberds

Reply to
mroberds

No, that is where the bridging pieces come in. There would be fixed rails on the bottom of the oven and fixed rails on the inside of the door. When the door was full open the rails would line up but there would be a gap between the bottom rails and the door rails - the bridging pieces would bridge the gap. As the wheels on the tray came out of the oven, then would initially be running on the bottom rails, then the bridging pieces and then the door rails.

Reply to
Palindr☻me

Thanks Matt. I actually have some heavy duty drawer slides (the type with an intermediate slide so the drawer can be extended completely out of the carcass). They are all-metal with no plastic. My only worries are the lubricants that will take 350 deg C. The oven sides get much hotter than the set temperature because that is where the heating elements are.

I can easily weld up some new trays to fit and get them chrome plated at a local shop that does such things.

I will have a go at yellow pages for the oil company references but lubricants aren't my field at all!

Reply to
Palindr☻me

Just looked at my oven, made in Australia, but principle should be much the same. Door opens down and is almost flat with bottom of oven when right down. If there was a set of rails on the bottom of the oven and another set on the door with just enough gap to clear the opening and closing, then the tray could have 2 sets of wheels or slides close to the front edge and that would allow it to bridge the gap without putting pieces in. For the number of movements and the relatively small weight slides with no rotating parts and no lubrication, might be enough.

Reply to
John G

Depending on how creative you get, you could probably find a dozen or more solutions to this problem. I have to agree that using a heavy-duty set of steel rails (Like the kind you find in heavy-duty filing cabinets) is probably the best idea. You are correct in worrying about the lubricants though. Here is another solution to deal with that. Have you considered replacing the steel wheels with solid teflon wheels? Then you could eliminate liquid lubrication altogether.

I know, this is the point where most people say, "Yeah right. Where on earth am I supposed to find solid teflon wheels!?" Good question. There are two possibilities that come to mind. Some time ago I found a place on the Internet that sold me the solid teflon balls that I needed for a project. I don't remember their name, but mention it only to prove the point that solid teflon parts are available commercially. They weren't very expensive either. I think I paid about $20 for 50 of them. If that doesn't pan out, there is always custom fabrication. In most cases this would be cost prohibitive, but it just so happens that my father is a retired machinist with a lathe and a surplus of old teflon parts in his garage. He may get a kick out of a project like this. (Disclaimer: I haven't asked him yet.)

If the latter sounds interesting, drop a line in this thread and I'll let you know how to get in touch with me. Good luck on your project!

-Peter P.

Reply to
Peter

meat-packing

seems like any sliders with ball bearings will soon get gummed up inside an oven. what about a fork lift device that reaches into the oven picks up the turkey, elevates it to table or counter height and sits it down again?

or maybe a simple adjustable height tray on wheels with a hook and winch to slide the turkey on to it.

Reply to
TimPerry

I like the miniature fork lift idea !

A modified small AC lift *Table, [* not sure if that's what they call em?]

Think about it };-) They won't have to bend down to the oven too long to baste and whatever else is done to turkeys and heavy baked goods ..... it could be lifted right up to them., rolled over to the table and served :-) yumm

I've seen some pretty snazzy electric carts with wired controls you can probably modify as well., money is a matter? why am i not a millionaire:( oh well

You get some weird challenges Sue

buena suerte

Reply to
Roy Q.T.

Reply to
robert grant

Anything you add to the inside of the oven will need to survive repeated delta T without deforming etc. Wheels will gum up at the axel and the wheel hub/axel will expand/contract due to delta T. You really need a simple, cheap, no moving parts solution.

If the oven in question is not already built with the following design (or a variation) this may help: The addition of one stud to each side of the oven near the front may be what you need. "Drawn" below is the existing oven tray with the added stud:

___________________________0______ === === === ===

=== are oven "bumps" or "rails" that the existing tray rests on and 0 is the stud. You could weld a lip to the rear of the tray such that it can't slide beyond the stud unless the front of the tray is lifted. There will be significant force against the stud with the tray fully extended, so how you mount it is important. Make it STRONG. I would affix a backing plate. By the way, I always assumed that this is the way most ovens are built to begin with, but your post got me thinking that perhaps that is not true.

You lose a couple of inches of your requirement (that the tray slide all the way) with the above proposed solution, as the loaded tray cannot be pulled out beyond the stud. So - is sliding the tray out where all but about 4 inches sticks out workable and useful? Is the oven in question already made that way? (It should be, in my opinion.)

That brings us to plan B. Instead of modifying the oven with parts that would be subjected to large delta T, how about an external transfer rack? You bring it to the oven, slide the oven tray out part way or all the way - whatever works - then slide the turkey off the oven rack onto the transfer rack.

The transfer rack can be a hinged affair with wheels so that when in operation it looks like a table, but it folds up for storage. The rack that receives the turkey would be removed for washing and to allow the thing to fold. H in the "diagram" below is the hinge. The washable rack would drop in at the proper height, locking the unit into a rectangular shape:

.| .| . | . | | | | | | | | | | |--------| | |---- rack----| | | | | | | |--------| | | . o | . o H-------------H o o

Are you by any chance associated with the group in Swindon that helps disabled folks? When I was devising a window opener for a disabled friend I contacted them. They do some very clever things! If you are not associated with them already, they might be able to help.

Ed

Reply to
ehsjr

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