Best mechanical extension springs according to redditors

There's a detailed instructable on this here: http://www.instructables.com/id/Making-Glove-One-a-3D-printed-wearable-cell-p/#step0


It looks like the finger bases are connected to the hand piece with extension springs : http://www.amazon.com/gp/product/B005V4HQ9I/ref=ox_sc_act_title_1?ie=UTF8&m=ATVPDKIKX0DER

And the finger segments are attached together with "snap-fit hinges" of some sort.

Page 744 of this book has more info: http://books.google.com/books?id=FzPEJyDTqtEC&pg=PA744&lpg=PA744&dq=plastic+snap+fit+hinge&source=bl&ots=xDFTctcUB7&sig=v5YWQS5q6mHpVmjcrXauBUp6vVk&hl=en&sa=X&ei=NRzPU5uAJrPesAT7_4DQAg&ved=0CGAQ6AEwCA#v=onepage&q=plastic%20snap%20fit%20hinge&f=false

(Plastics Engineering Handbook Of The Society Of The Plastics Industry)

Here you go:
https://www.amazon.com/gp/product/B000H5SJGA/ref=ox_sc_act_title_2?smid=A1AUFI5NHGNZ61&psc=1
https://www.amazon.com/gp/product/B0031HT8JS/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

​

You can also do the trunk:

https://www.youtube.com/watch?v=o5Dun6iNnoY

StrongArm 6304 Jeep Grand... https://www.amazon.com/dp/B0031HT8JS?ref=ppx_pop_mob_ap_share

I bought two of these. Had to buy two singles for some reason amazon wouldn’t ship a pair to California.

Century Spring C-77 2 Count... https://www.amazon.com/dp/B000H5SJGA?ref=ppx_pop_mob_ap_share

Bought this spring.

There are several how to videos. The process is simple and takes 5 minutes. remove oem shock replace, remove second oem shock replace. Test opening function. Then pull up the cover that has the illuminated frunk release button and replace heavy spring with lightweight one.

One of the how to videos showed that doing this does not prevent the frunk safety catch from operating.

Edit video https://imgur.com/a/K3cUFZ1

Century Spring C-77 2 Count... https://www.amazon.com/dp/B000H5SJGA?ref=ppx_pop_mob_ap_share

Took those and and relaxed the latch spring with them.

It looks like it would, but I'm not sure what the difference is between a long low force extension spring and a long multiple rotation torsion spring. I may try an extension spring an see how it works out. Might be good enough for a prototype.

 

Here is something close to what I am looking for. This is obviously designed as an extension spring, not a torsion spring, but it has similar dimensions.

I think rigging it so that the door closes automatically would be the way to go. Low tech.

Maybe a weak spring could provide enough force to slowly pull it shut without adding so much resistance that it make it hard for her.

Or, perhaps a stiff material (or spring in compression) could be mounted outside, such that it flexes when the door is open, but provides resistance to push the door shut.

If you wanted to use a technical solution, then perhaps it would be possible to rig something up by adapting an online project for an automated door opener/closer.

I just think that having a door sensor trigger an alarm that you then have to manually check and call her on the phone for her to go close the door is very much the long way to solve the problem, when a $10 spring from the hardware store might solve the problem directly. :-)

I replaced the frunk spring with this one and I can easily close with one hand now.


Century Spring C-77 2 Count 1-7/8" Extension Springs with 11/32" Outside Diameter https://www.amazon.com/dp/B000H5SJGA/ref=cm_sw_r_cp_api_i_OyYzDbMDNBKG9