584,798 active members*
4,187 visitors online*
Register for free
Login
Results 1 to 8 of 8
  1. #1
    Join Date
    Aug 2005
    Posts
    135

    Question Constant Force Pneumatics?

    Can anyone help me?

    I have an Airpel double acting pneumatic cylinder.
    Here's what I would like to do;
    Have a mass balanced in any linear position just like a constant force spring.
    Q:
    Is there a special valve(system?) required to be able to do this?
    I just cannot seem to find the right keywords for Google.

    Thanks!

  2. #2
    Join Date
    Jul 2004
    Posts
    233

    Re: Constant Force Pneumatics?

    Yes,

    What you do, is use a "Precision Air Regulator"... this is like other air pressure regulators, except... it will maintain an exact setting. So you want 20lbs of pressure. If the pressure is higher, it will release some air, and if the pressure drops, it will add some air. You always have exactly 20 lb's of pressure. the regulator handles it all for you. As well, with the regulator, it is easy to adjust.

    Warning: They are not cheap... maybe around $100.00 for a small one.
    Robot & Machine Design - BLUECNC4, GreenCNC3, RedCNC2L, SilverCNC2; CNC Software!
    www.truemachinedesign.com - - - - - - - - - - - - - www.truemachineautomation.com

  3. #3
    Join Date
    Aug 2005
    Posts
    135

    Re: Constant Force Pneumatics?

    Aha! Thank you jeffserv for your help.:banana:

    I just wish you were wrong about the cost. Even on eBay they're expensive. I need 6 of them

  4. #4
    Join Date
    Jun 2005
    Posts
    24

    Re: Constant Force Pneumatics?

    If you connect one of the inlets to an accumulator tank that has a significantly larger volume then the cylinder, you can just pressurize the tank to your desired force and leave it alone.
    It's not going to be perfectly uniform but you can get pretty close if you have a big enough accumulator.
    It works much like a very - very - long spring.
    Larger diameter and shorter run piping would reduce drag when it's changing position quickly.
    Not pretty, but it's cheap.

  5. #5
    Join Date
    Oct 2004
    Posts
    178

    Re: Constant Force Pneumatics?

    what you want is not a pressure regulator if I understand your question, but meter out flow control valves on each end of the cylinder. This gives you good control of speed, without a loss of power

  6. #6
    Join Date
    Aug 2005
    Posts
    135

    Re: Constant Force Pneumatics?

    Well, the answer from jeffserv doesn't explain how the regulators would work for double acting cylinder. I suppose just leave one open?

    So I hope I can make it clearer what I mean;
    I need to be able to move a mass to a new position and make it stay there, hopefully nice and "rigid" as possible. When I apply a force to the mass, it should move until I take my hand off it then stay there.
    I suppose there should be a way for a valve (or whatever) at either end to monitor the pressure and once one is higher than the other, transfer air to the opposite end.
    It won't be changing position quickly either, in fact it will be mostly stationary and any motion when force is applied will be quite slow.

    Sounds like greggv has probably got the answer. I'll look into these valves.
    Thanks everyone.

  7. #7
    Join Date
    Feb 2009
    Posts
    6028

    Re: Constant Force Pneumatics?

    Look up auto leveling air isolators. Same concept your trying to achieve.

  8. #8
    Join Date
    Aug 2005
    Posts
    135

Similar Threads

  1. Constant Drilling Force
    By mcfa001 in forum Mechanical Calculations/Engineering Design
    Replies: 4
    Last Post: 04-26-2012, 06:44 PM
  2. Constant Force Springs
    By rrobb in forum Benchtop Machines
    Replies: 2
    Last Post: 09-06-2011, 08:23 PM
  3. Pneumatics Help Needed
    By devers6 in forum Benchtop Machines
    Replies: 22
    Last Post: 01-15-2011, 04:25 AM
  4. Constant Force Spring for Counter Balance
    By biomed_eng in forum DIY CNC Router Table Machines
    Replies: 2
    Last Post: 10-25-2006, 03:10 PM
  5. How to make a Constant Force Spring
    By jwvica01 in forum Benchtop Machines
    Replies: 0
    Last Post: 06-28-2005, 01:17 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •