butterfly or biased hinge

[delbert]

Anyone have any information on the design of a living butterfly or biased hinge such that is used on a flip top closure?

I have designed several living hinges in the past but I don't have any experience designing a living butterfly hinge.

The patent on this hinge has expired so there seems to be very little information out there right now.

Any help would be appreciated.

Thx,
Delbert

 

[Hacks]

Check this out...not sure if it's exactly what you are looking
for or not but it's informative nevertheless...


http://www.profilesmagazine.com/p15/tips_spinal.html

 

[delbert]

Thanks but that link is just a living hinge. I need info on a biased/butterfly living hinge like a snap closure/lid you might see on a bottle of shampoo.
Edited by: delbert

 

[mgnt8]

I've taken a stab at modeling one or two. The Spinal Bend feature won't work for it. The only way I see to model it in the open & closed position is two separate features or models. Otherwise keep your wall thickness at .010 to .015 and leave a little bit of slack on the edges for bending. Do you mind sharing the patent number?

 

[delbert]

I don't know what the patent # is but a firm that does nothing but design butterfly hinges assured me that it has expired.

I am not looking for modeling techniques, I can model the hinge. What i am looking for are some specs: formulas, radii, wall thicknesses, etc...

I could design the hinge from off the shelf examples, make a prototype mold in our shop and through trial and error make a hinge that works. But even small discepencies in the design could cause the hinge to be "lazy" and not snap very well if at all.

The firm that designs the closure hinges said for $4000 they would design the hinge between the two closure pieces and give me the finished closure with the hinge added. But they will not disclose their methods, formulas or any other information on how they would come up with the design.

THIS is what I am looking for. Seems like someone with butterfly hinge experience could make some money by writing a design guideline book.

Thanks,
Delbert

 

[AHA-D]

Or someone with experience can make more money by NOT writing a book ....


Alex