Well.... Grab a
and maybe a beverage...
..or...just find something better to do.....
In the first diagram: "A", You can see the line of travel of the piston is even with the bottom of the pulley. You can see it has a full range of travel....however, it's weak point is shown in the diagram. First, it's been backing up until this point, so it has zero power, at this point, the leverage is the weakest....now to even consider engagement to start crushing a can....it would need to go inbetween where it is now and another 1/4 turn....at that point , however, the angle between the piston and connecting rod would be very weak....(We'll come back to this a couple of times later.
Looking at "B": We see the same plane of travel with the the piston at it's strongest position : max force of angle, and nearly the max inertia
Now, this is great to start crushing a can, but from there to somewhere around that x coming up is all the travel you get in that direction....So, what I shot for in Poboy Crusher one was x on the left (to engage the can) to x on the right to finish the crush.
That actually worked very well....however, dummy that I am, I failed to consider something.....Look back at figure "A".....Now.....this is where the piston needs to change direction on the backstroke...only at the top (12: o'clock)....(approximately) ....anyway that sharp angle promoted binding, (especially with the sloppy tolerances on crusher one).....So...I had to look to improve the angles at that point ..
Raising the travel line towards the center is the obvious solution....(as well as a longer rod....but I'm not going there right now....
So....in "C": We see the benefits and drawbacks of a centerline track:
First off....it has the longest possible travel, however, obviously, it would have to get to x before you can even think about trying to crush a can...and then you would be at "D" midway through the crushing process....not good....
Now, you could engage around 10:00. (remember, this is turning counterclockwise) ....and you would basically have the same powerstroke as crusher one...The problem is at "D": we have that weak point that basically can either jam or go backwards! !!!
So tomorrow I post up some pics of how I set it up with the critical points of contact and direction change....(It's all a bit of a crapshoot and a "best guess " until it fires up....
.....and you'll see it's a camping sized propane cylinder...