Plastic Snap In/Out Ball & Socket Design

Question

Plastic Snap In/Out Ball & Socket Design

TStuart (Mechanical)

(OP)

17 Apr 01 13:52

Are there any standard design parameters for constructing a snap in/out ball and socket joint for plastic components? For example, what percentage over center should the socket be molded to allow for the ball to snap in and out of joint. Or do designers run FEA on each case to determine pull-out stresses?

Thanks,
Tom

**guest0821** (visitor) · Answer 1 · 2001-04-17 18:06:13

Seems to me it might be a constant proportion limited by the elastic limit of your material.
Gap
Tolerance
over center distance
friction
extra support from a cup of other material could change everything!

friction will be dependant upon material and force
force will be dependant on deflection and material
deflection will be dependant on tolerance and gap and over center distance.

solve in 2d and integrate to get 3d. Doubt you'll need anything more exotic than a pencil, paper, and a calculator or spread sheet to get pretty close

Larry

diamondjim (Mechanical) · Answer 2 · 2001-04-20 22:56:15

T.
Assuming that you are only using a small tang
or interference at 120 degrees or at 180 degrees
I would make the tangs have an interference of
about 1/64 or less and only go in from the surface
a 1/32 depending on the cage cross section. Note
that many such designs are commercially available.
I do not know if you are designing radial bearing,
linear bearing or what.

Come Join Us!

Posting Guidelines

Plastic Snap In/Out Ball & Socket Design