simultaneous operation of 4 pneumatic components
simultaneous operation of 4 pneumatic components
(OP)
what is the best (cheapest) way to ensure simultaneous operation of 4 separate pneumatic components. The cylinders will be identical and must lift together (squarely,...is that a word?). I was thinking of using a single large valve feeding a manifold which feeds the supply lines to the components. Any suggestions?





RE: simultaneous operation of 4 pneumatic components
i am not sure how wide the area plus the weight you want to lift but if it is not too great yes you are better off using a large valve with flow control and just using one big cylinder lifting the whole plate.
or another combination is using a manifold for four valve supplying your cylinders with individual flow control so you can control the speed but the chances of going out of square is greater than the first set up i mentioned above...
can you give more info on the application including the weight and speed of lift?
dydt
RE: simultaneous operation of 4 pneumatic components
The apparatus will be about 8 feet long, 2 feet wide, 3 feet tall and could be made from aluminum etc. With the load i would estimate total at 100-150 lbs. Lets go nuts and say 250. I don't think i would want to try and do this with one cylinder in the center.
RE: simultaneous operation of 4 pneumatic components
RE: simultaneous operation of 4 pneumatic components
If multiple cylinders are used, you'll need to run them slow enough so that the pressure is not flow-limited.
Additionally, you can mechanically arrange for the load to be driven from a single point. if you have two cylinders; they can be coupled to a crossbeam that supports your load at its c.g. through a pivot support.
TTFN
RE: simultaneous operation of 4 pneumatic components
RE: simultaneous operation of 4 pneumatic components
Probably your best bet would be to center one flow control valve in the center of the two cylinders and drastically oversize your flow capablities to ensure that pressure does not drop too much during operation.
RE: simultaneous operation of 4 pneumatic components
If you want to see what I did send me your email address and I will email you that section of the machine.
lesliehowell@howellconsulting.com
The name consulting is for more resonable insurance.
Sincerely yours,
Leslie H. Howell
RE: simultaneous operation of 4 pneumatic components
RE: simultaneous operation of 4 pneumatic components
<nbucska@pcperipherals.com>
RE: simultaneous operation of 4 pneumatic components
You'd be bitter off reconsidering your mechanism. Using some minimum constraint design techniques, you could develop a system that could operate off of one cylinder. I could offer support on that or you could refer to a book like Lawrence Kamm's Designing Cost Efficient Mechanisms.
CHUCK
www.pitzerconsulting.com/hidden/index.html
RE: simultaneous operation of 4 pneumatic components
I've Just bult a machine with a lift very similar to the one that you describe, we used a single 80mm bore cylinder & two pivot points to lift a total mass of around 300 kg with a travel of around 150mm, I can email you some photos if you like
Regards Russell Gee
RE: simultaneous operation of 4 pneumatic components
Good luck
RE: simultaneous operation of 4 pneumatic components
It sounds like you have a very interesting project. I have developed several multi-cylinder lifting systems (synchronous-lifting) for a variety of industries, and the problems I encountered are identical to those you have described. I have seen several lifting-system applications that attempted to accomplish the task by tying all the lifting cylinders together to a single valve. The consistent problem with this approach (as you’ve already realized), is that unless the center of gravity of the load sits directly at the geometric center of the lifting stations, the cylinders will “see” different load values. Because the cylinders are driven from a single valve, they all see the same pressure, and thus have the same lifting force. Attempting to raise or lower an “unbalanced” load like this will result in the lightest-loaded cylinder moving the fastest, and the heaviest loaded cylinder moving the slowest. Not good if you are trying to lift something and position it accurately. This approach may well be workable for lighter load applications that do not require a high degree of positional accuracy. However, I have had to develop lifting systems capable of lifting several tons with an accuracy tolerance of +/- 1 mm between cylinders, and the single valve theory just would not cut it. The only method that I’ve found to provide absolute robust operation of a multi-cylinder lifting/positioning system is to use position sensing of each cylinder and feed that information back to a microcontroller. The controller in turn operates a single valve per cylinder, servoing on the position of each cylinder from a datum reference. In this manner, each cylinder is independent of the other cylinders; changes in system pressure; or lifting load changes as the load may shift during the lift sequence. If your lifting application is a dedicated system (i.e. you’re always going to be lifting the same thing to the same position), then the single valve or mechanical balance system might work. However if your application will encounter varying loads with different weight distributions, then a “semi-intelligent” lifting system may be the only practical solution. To answer your initial question of the “best (cheapest) way to ensure simultaneous operation of 4 separate pneumatic components” is usually an engineering contradiction in terms. We are always searching for the “best” and most cost-effective solution, but those two guys rarely play well together. You can have the “best” OR you can have the “cheapest”, but trying to get both really makes our profession interesting. Best of luck with your project!
RE: simultaneous operation of 4 pneumatic components
RE: simultaneous operation of 4 pneumatic components
If you have not already built the device in question, let me know, and I will provide you with all the guidance you want.
RE: simultaneous operation of 4 pneumatic components
Just curious -- sorry I really don't have a solution for the pneumatic load balancing problem. If the load is identical weight for each lifting operation and is positioned precisely the same each time then all of the folks who have respomded have reasonable solutions.
Goo Luck,
ietech
RE: simultaneous operation of 4 pneumatic components
Basically, you have all confirmed my original thoughts on this dilema. There are several good ideas here.
And, you're right "BEST" and "CHEAPEST" don't get together very often.
This project was kiboshed by the customer, but, again thanx for your comments!!!