help! Need search term!

[subsearobot]

Hi! I need a "spring" that behaves like a dome switch, but bigger:

the output of which would be a step function if plotted displacement vs. force. (there is no electrical requirement for this thing)

I hope for limited travel (<.050"), with a force threshold of about 8pounds. The item woudl need to have an outer diameter of about .875", and a bore of at least .50".

please comment on feasibility (this is a pie is the sky mechanism, I'm not sure it can be done, but would solve certain problems if so). Also, search terms for said item if I have described an off-the-shelf product! I will, of course, be calling my spring expert, but I like to approach manufacturers with a clue of what I really need...


thanks

 

[JohnRBaker]

Try "belleville washer" and "conical spring washer".

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[israelkk]

What do you mean by "a force threshold of about 8 pounds"?
Does it has to snap through (Bi-stable)? If yes, how much force is needed to return it to previous position?

 

[subsearobot]

I had dismissed bellvilles because I thought they had a rather linear force/displacement profile. Assumptions.... Nice, that would be easy! Not sure I have the axial space, but crossing my fingers.

Yes, I'd like it to snap through at about 8#, and return to original shape after the force is removed.

The concept being: a small handheld instrument, shaped like an electric toothbrush. Imagine attaching the "disposable toothbrush" to the body of the unit by pressing the two together. I want a tactile feedback that the person has installed if pressed together with enough force. I want the displacement to return when the force is removed. there's not very much space (axial, nor radial), so I'm looking for a space efficient solution.

other ideas are very welcome- I'm just spit-balling here.

(we are not making tooth brushes, just an example 'cuz secrecy.)

 

[israelkk]

It seems that it can be achieved in the outer and inner diameter limits. Maximum deflection is under 1 mm. However, I doubt you can find a spring off the shelf. You may need to custom design and manufacture it.

https://sites.google.com/site/israelkk/

 

[MintJulep]

This can be done with a "snap ring" and grooves on ID and OD and possibly a taper leading into the groove.

https://www.rotorclip.com/prod_constant_section_snap_rings.php

 

[Strong]

How about "ball detent locking mechanism"

Walt