What's new
What's new

Quick release spacer

Strostkovy

Stainless
Joined
Oct 29, 2017
I'm designing jigs for our welding robot that is arriving soon, and a common thing to need is a spacer that fits between two sections of a weldment to hold a critical dimension. When hand welding the extra time it takes to force the spacers out isn't a huge deal, but it matters more when trying to keep up with a robot, as well as having to deal with galling. Sometimes we use spreader bars and adjust the force to maintain an opening, but the robot can't do that either.

So what I would like to design is a spacer assembly that either has a lever or pneumatic cylinder that goes from being solidly at a known thickness (able to withstand moderate clamping forces) and then be easy to quickly shrink it my 1/16" or so.

Has anybody seen or made something similar? I've come up with a few concepts but nothing very elegant.
 

DanielG

Stainless
Joined
Oct 22, 2014
Location
Maine
I haven't seen anything off the shelf. The last place I worked built their own for use in aircraft jigs. They were quite thick though. How thick of spacers are you dealing with?
 

Strostkovy

Stainless
Joined
Oct 29, 2017
I haven't seen anything off the shelf. The last place I worked built their own for use in aircraft jigs. They were quite thick though. How thick of spacers are you dealing with?

3/4 is the smallest, but typically several inches
 

tonymor

Aluminum
Joined
Feb 9, 2017
Location
Chambersburg PA USA
Some kind of sketch of what you're working on would probably help.

Here's something we're actually just trying out at the moment to keep two plates correctly spaced while we weld.

Two separate plates with steps milled in them. Blue line is your spacer thickness, red line is your clamp.
The step where the plates meet is milled back further.
When the clamp is released the spacer can collapse in on itself.


Spacer.jpg
 
Joined
Jan 24, 2022
These are great problems to figure out. For similar one-off situations, I've used Allen keys as "cams" -- the corner to corner dimension is greater than the flat-to-flat (on a 3/8" key, that differential is about 1/16"), and they come with a built-in lever. Maybe some modified version of that?
 

Strostkovy

Stainless
Joined
Oct 29, 2017
Some kind of sketch of what you're working on would probably help.

Here's something we're actually just trying out at the moment to keep two plates correctly spaced while we weld.

Two separate plates with steps milled in them. Blue line is your spacer thickness, red line is your clamp.
The step where the plates meet is milled back further.
When the clamp is released the spacer can collapse in on itself.


View attachment 341066

That might be just the elegant solution I was looking for. I might use a coarse thread cap screw and some math so that 1/4 turn releases it the right distance.

Even better is that I can make this on our laser with stacked plate
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
Cam or eccentric? Carr-Lane has a bunch of fixture components with cam mechanisms. Might be worth a look for inspiration.
 








 
Top