My car has a clever cup holder lid that, when lightly tapped, opens slowly and smoothly by itself. Anyone know what its hinge is called? I have looked in McMaster Carr's catalog but can't find spring hinges that work this way. I took apart my Sony video camera with a similar tape-ejection mechanism and it seems to operate with two different-strength expansion springs and curved tracks. I would like to add this type of spring to a small box lid but I don't want to disasemble my car's cup holder or visit a junk yard to find one! Anyone know a source?
Dave

I don't have a source but it somes similar to a constant torque spring mechanism. Basically, two spring loaded cans that transfer between the two. I was going to suggest McMaster Carr.

Have you tried C&H Sales or American Scientific's websites. They have a lot of weird closeout stuff.

Richard

Go look for the "magic" calculator, it is a spring flip back top that moves slowly, they are just a couple bucks for a take apart item, that will still leave you with a calculator to use!

Richard, I couldn't find my slow-opening spring hinge at American Science and Surplus. C&H Electronic Sales' site must be down because it wouldn't load using either of my browsers. I'll try again tomorrow. Wish I knew the name of this type of hinge, it would make searching more efficient. Kay, I will look for a "magic calculator'. Where did you see these? I live in Sacramento and we may have chain stores like yours in central California.

Ask your auto mechanic the name of the supplier or go to a junk yard and get one.

Sorry, I don't know what it is called. Could you use a spring loaded hinge to open with a counter balanced reel? Just brainstorming.

Richard

Hi Dave, I am in Stockton, and the calculator I had was a promo from Baycon for inspector gadget, but I will look it up , they are out there pretty commonly, usually from the imprint folks. give me a few and I will find a source for you
k

Here is a link to a supplier, realize they sell them in bulk for promotional work, but you might be able to order a single one as a sample, otherwise google on flip top calculator!
http://www.bestimpressions.com/fliptopcal.html

Thanks Kay. After reading your message I went to the web looking for "flip top calculators" and found literally dozens of companies selling them in bulk as advertizing novelties. I wil look locally to find a single one so I can play with the lid. Sounds like a good possibility!
Dave

Michael Baker is a hinge expert. Maybe he will see this thread and chime in??? Wish I could help. SOunds interesting though.

-=tabman

Dave, I also recall Tony Andruzzi giving information in making a self opening hinged lid for a box, (or book) it moved slowly due to the weight of the box lid. It was in one of his books, and somewhere in the Invocation. If you think it would work, shoot me a PM and I will try to get you the exact source. Very easy to make, and quite inexpensive, maybe $5 for enough of the material to last you several hinges.
Not sure of your needs, so it may not be what youare looking for.
k

If you still have a problem finding a single calculator, try actually going to a trade show. Usually, access to the vendor booths are free. Go and look interested and you should be able to have many vendors give you them for free. With many new victims in hand, the method of operation should be easy to figure out. If I can find a victim in my pile of junk, I'll take it apart and let you know.

Alan

Dave;
Use a regular spring hinge or custom make what you need lubricated with damping grease. This is what is used on CD players, calculators, etc. You may get a sample kit here:

http://www.nyelubricants.com/2002_311.htm

These special greases are very "tacky" and will do the job. Good luck.
Jim

Thanks Kay, I wil look for the mentionin Invocation. Jim, I had never heard of "damping grease". What a clever, and logical idea to slow motion! Thanks for the link.
Dave