In/out motion by twist 2

The pink rod has prismatic joint with blue body.
Twist the knurled grip clockwise to get out motion of the rod.
Twist the knurled grip back to get in motion of the rod.
The red pin fixed to orange core slides in the slot of green barrel cam.
The green spring and suitable shape of the cam slot keep the rod stable at its in/out positions.
The disadvantage of this mechanism: the in/out stroke length can not be large because the cam pressure angle must be kept small enough for easy motion.
The mechanism can be applied to twist pens.

STEP files of this video:
http://www.mediafire.com/file/j6v60xs...
Inventor files of this video:
http://www.mediafire.com/file/cj0607r...