Hi, I feel the mechanism is OK as its the first this you have designed based on your requirement. I feel you can further optimize it by having a grooved cam profile in the shaft itself. The handing arm an have a small link with roller which can go in the cam slot.
I feel that the mechanism is way too complex. If I understand what you're trying to do, collapse the arm with a rotary motion, then the blue translator should hook directly to the lever attached to the green arm with just a link to allow rotation motion to straight line motion or the blue part could have a slot to accommodate the relative motion.
are you trying to convert rotation to translation or vice-versa? if vice versa i think as someone mentioned above you my have singularities to deal with.
I can't see that working in reality. Too complex and fragile. An alternative would be to flip the cam upside down. Have a cam wheel ride on it attached to a link that passes through the green collar. Put a pin through the lower end of the link which runs in a slotted plate attached to the green arm.
For a simpler method I would suggest two spring wrap clutches on the cylinder attached to the lever by short cables. As the lever is pumped in and out the clutches will alternately drive and return rotating the shaft. If a continuity of rotation is required a flywheel on the shaft would provide a measure of energy storage and delivery. Does this make sense? or do you need a drawing.
How about using a cable, lifting the lever instead of pushing down on the lever. Place a pin off-center on the upper plate. Attach the cable end using some form of bearing sleeve. Place a pulley in the plane of the rotating pin, so that the cable will be pulled away from the pulley as the shaft rotates. Place another pulley at 90° to change the direction of the cable to a vertical plane. Attach the other end of the cable to the lever on the arm, so as the shaft turns, it pulls the cable, lifting the arm, and as it proceeds around it lowers the arm. Pin offset and lever length are all that need to be changed to get the proper travel. Pulley diameter is important to ensure proper cable life. Depending on the scale, any high modulus tension element (sections of belt, aramid fiber, wire rope, chain) could be used. Redundant elements can provide reliability and safety, and permit easy change-out of the tension elements as required. Lifting on the lever will automatically reduce instead of increase friction and binding. Simple, compact, cheap.
Like this approach. Basically a bicycle (or tricycle) pedal arrangement. Couldn't be much simpler. Still needs the flywheel to power the shaft through the dead area but that's not a serious drawback. Still need an answer from the original architectural poster about what the rotating shaft is doing for 12 hours. Who is pumping the lever on a 12 hr shift
This is a simple, cheap and robust way of doing it. https://www.dropbox.com/s/w2rwi98kms6pswz/2013-03-29 12.02.19.jpg Please excuse the swift hand sketch.
One thing you can use which let's go from rotation to translation is a CAM. A CAM is a profile that is superimposed on top of a circle. The bumps and valleys translate the CAM Follower up and down which creates a translation motion. CAM is connected to a motor or something like that. Hope that helps. Look up CAM on youtube.
The linkage has too much force on it, specially the last one on the green bar. Do you consider lead screws gears? This would be a lot simpler with a slot-cam driving the lever of the green bar directly. You can also control the timing much better? No yellow part, a simple pivot somewhere, not red parts or blue part. What is the scale and load of the mechanism? What is the environment?
