Laser cut thickness.

A project log for COSV - Cam Open Source Ventilator

Roller cam based portable BVM ventilator.

Daren SchwenkeDaren Schwenke 04/02/2020 at 13:400 Comments

The thickness for the bearings versus the parts when laser cut was a little bit of a problem.  The bearings are 7mm and common material is 6.35mm or 3.175mm.

14mm is a nicer number, and also allows us to use washers on both sides of the arm bearings, which eliminates the stress on the bushings and the odd thickness requirement there.

So two arms cut from 6.35mm sandwiching a third cut from 3.175mm and we got a total thickness of 15.875mm.

Two regular washers positioned on either side of the bearings will make up that difference, and provide a larger clamping surface for bolting it together.  The bushings then just keep the bearings centered and don't have to support the compressive load anymore.  Also keeps things from flopping around.

Then for the cam we also use two stacked bearings.  More area to wear on, and the bolt heads from the cam bolts no longer needs as much clearance as they will be at the same height as the now thicker cam surface.

I'll model it today and put up an image of this so you can see what I'm talking about, but I think this will be better.  No new parts needed either, just duplicates of what we already have too, minus the paddle.  It will need a wider hole.