Alibre CAD. Parker pen retracting mechanism

This is an interesting Alibre project if you want a practical and clever mechanism to draw then manipulate.
I've been goofing about a bit and stumbled across this by pure luck.

How many of us have taken our retractable ball point to bits at some point in the last 50 years and stared at those funny little plastic cams... and slipped the spring on and off the pointy end?
We listened to that double click as it did its business... and then something in class happened and we scrambled to get it put back together and get writing again...

The Parker retractable ball point pen and its mysterious inner workings apparently took a team of over 60 people to design and sold over 500,000,000 units.
At 1p a unit royalty.. well 1d up to 1970 actually... that's £2.5 million quid when a decent house with a garden was £1000 a pop.

and you can do it in Alibre.

I have tried to simplify it as much as possible and what you have here is like a rotating bolt mechanism that the armaments industry uses, where the same movement produces a different result in the cycle, and it is a very reliable mechanism that can be repeated thousands of times.

The bottom spring keeps the mechanism in compression at all times and forces the cams to do their job.
You can see the writing point go up and down, towards and away from the plane as I cycle the top push button.The really clever bit is that the turn goes an eighth-way on the down push(45 degrees), and another eighth movement happens as you release it, using both the down and the up movement to go 90 degrees and creating that double-click sound from one thumb press.
This also means the ball point tip rotates as it is used and extends its useful life.
I have put little nodules onto the writing tip so you can watch it go round.

I got my inspiration from these guys.   • How a Retractable Ballpoint Pen Works