I need help figuring out the most efficient way (NOT electronically) to manually compress plastic in a small confined space. I was thinking there were small compression shocks that would help to triple my human body force but have been unsuccessful in finding something that works.
closed as too broad by Air Oct 14 '16 at 16:47
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Levers are your friends: a lever allows you to multiply up the force of your own strength. Here's a manual can crusher, demonstrating this:
Your hand moves three or four times the distance that the crushing part does; as a result, the crushing part moves with three or four times the force that your hand does.
A bench press or arbor press, combined with a suitable die for horizontal containment, will allow you to produce rather high forces and pressures.
Do you have any numbers — volume, pressure, etc. — regarding exactly what it is you're trying to achieve?
EDIT: I have to confess that I missed the waste-disposal tag on my first reading, so my first suggestion isn't very practical in that application. Probably the most compact mechanism that can provide both the required force (about a ton) and the travel distance (18" to 24") is the "scissors jack" — but it requires a lot of cranking to operate that might not sit well with users.
I'm not clear from your question if you are trying to crush a plastic object, or manipulate hot plastic (eg for injection molding.) Lever systems are certainly a good option as has been mentioned in other posts, but depending on your application, a compact lever may not provide enough force for you..
If you need more force, hand-pumped hydraulic jacks will let you get a serious amount of force in a small space. For example, Enerpac makes a 2.25"x1.5" cylinder that generates 5 tons of force or a 5"x5" cylinder that generates 60 tons of force. Hydraulic hand pumps are readily available although the cylinder will move very slowly.