What exactly is a damper gear or rotary gear?

[TheMachinist77]

I'm designing a flip-down door on a high end video/audio system and someone told me I needed this rotary damper or gear damper to slow the opening and closing of the door. I looked at the cassete tape decks, DVD players, CD-ROM and notice gears are making this happen.

My knowledge of gears can fit into a thimble. I have no idea how to set the gear ratio, what number of gear teeth I need, if the mating rotary gear has 11 teeth, what diameter size gear I need, etc.

Can you guys give me some useful pointers?

 

[SincoTC]

Most of these loading devices employ a damper of some kind, usually comprising a sprung loaded thin gear, bearing against a plate with a special grade of silicone grease whose shearing properties give that silky feel. The art is ensuring the right degree if damping without stick-slip and the ability to give long service without variation of these properties. You should find them fairly easily on the Web, We use some made by Ondrives. They can be quite small and cheap.

 

[hydtools]

I have also seen drives that turn a very small fan to slow the door opening. An air retarder of sorts.

Ted

 

[ScottyUK]

This is typical of the grease used:

http://www.rocol.com/lubricants/english/maintenance/damping/

Kilopoise is a Rocol trade name but it seems fairly well known as a generic name for high viscosity grease.


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If we learn from our mistakes I'm getting a great education!

 

[SincoTC]

Kilopoise is the Rocol trade name, we use a light and a heavy grade and our name for them is "Super-Snot" and "Mega-Snot". They're great, except when you have to get it off your fingers!!


Trevor Clarke. (R & D) Scientific Instruments.Somerset. UK

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[williedawg]

relative to what hydtools mentioned.... look inside your mom's/sister's/wife's music box. The mechanism typically has a small 2-bladed fan that spins to regulate the speed of the drum.

 

[hydtools]

See this catalog:

http://www.aishouston.com/images/ace_controls/catalogs/rdampercatalog.pdf

Ted

 

[hydtools]

See also:

http://www.richco-inc.com/browseframes.asp

Ted