As part of a school project, I have to design a 33cl can compactor. For the moment I am studying different systems (connecting rod/crank, eccentric, cam, etc...). I'm currently working on a cam system: the cam pushes the push rod which itself will crush the bobbin... In order to keep the roller in contact with the cam, I plan 2 springs. But I have trouble determining by calculation on the one hand the springs I need, then to determine the force needed both to compact the bobbin and the force necessary to tension the 2 springs.
To crush the can, I start with a force of 1500 N. To this force, I have to add a force F for the springs, but I don't know how to determine it... The stroke that compacts the bobbin is 90 mm.
Is my reasoning correct? Ps: I'm attaching a screenshot.
Thank you in advance for the help you can give me.
Since you choose a cam, I believe that you complicate yourself Covid, sorry, complicate your life. All you have to do is makea cam path so the round trip is insured without spring, which simplifies your design. Also, if you put a cam path on top and underneath your push rod will still be centered with my stress on the axles.
Moreover, 1500 N is totally excessive, 60 N is more than enough for three reasons. From the moment you use an eccentric (a connecting rod or a cam), the force increases to an infinite force (within the limit of the RDM).
In addition, he has a great trick to reduce the effort to be made if the two ends of the can are strictly parallel then the effort at the beginning is important (remember if you stand on a bobbin the slightest flick on the cylinder (the side) there makes you crush instantly (you just have to remove your fingers very quickly ;-) if not boo-boo). So if you make sure that the two compression pieces are not quite parallel, (or that there is a growth on one of the two compression plates) the forces to be made are ridiculously low, especially if you use a cam.
Thank you Zozo, thank you Aliende, thank you Gt22,
Not bad the trick of non-parallel planes to compact the can, but I would have to be able to determine the less force I don't need anymore by calculation - (Don't bother, just thinking to myself).
I use a belt because the eccentric will be driven by an electric motor: so I illustrated a belt in SdWks, should we favor something else? Gears, chain??
Thank you again for your answers, have a good weekend!
A simple geared motor will do the trick, it's more compact, more instant torque, more reliable in dirty environments (compacted cans make juice and sugar everywhere.
For the calculation, if you have a water pack placed on your can and give two simultaneous flicks on each side with a stick and Prouiiiqk it's compacted. Start with a bottle, then two, then three on a wooden plate and you'll see. You can replace the water pack with a little brother or sister, it will amuse them right now.
Remember with a geared motor and a cam the forces are proportional. So very strong when the bearing is on the outer diameter of the cam. The compression speed is not constant either if you make a simple cam (like my model.
Kind regards
PS: be careful, it seems to me that the large cans do more than the race you indicate.
Yes, but! As @Fabrice says he has explored [[ study of different systems (connecting rod/crank, eccentric, cam, etc...). I'm currently working on a cam system]]: I only proposed a very slight improvement of his ASM. ;-) ;-)
It spins at 7500 rpm and I would like my cam to spin at 10 rpm... Is it an exaggerated speed for the engine or won't it cause problems? I'm going to use gears at first before trying something else.
As far as the spring calculation is concerned, it's a bit complicated for me, so I'm not going to take it into account.
The youtube video of the crank connecting rod compactor allows me to propose another idea, quite simply, and yes it's easier for me to do without springs.
Finally, I have a professional Baccalaureate EDPI level and I followed a literary course in the past, so I'm not an engineer, there are a lot of things I don't know so I discover, I understand and I learn. The interest for me is not to do things perfectly but to get something positive out of them.
