Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Accelerating a Mass with pneumatics

Accelerating a Mass with pneumatics

Accelerating a Mass with pneumatics

Hey all,

Not sure I am posting in the right forum, but here it goes.

I need to simulate a mass falling from 10 meters, but only have about a meter of height to do it in. Therefore I need a method of accelerating the mass to a certain velocity, and then release the weight halfway through its travel so the mass is in free-fall at the time of impact.

The first thought that comes to mind is a pneumatic system with a magnet as a release. As long as the stroke of the piston is shorter then the 1 meter height, it would essentially give the weight a "boost" at the beginning of its drop. However i do not know if this is possible with pneumatics. Has anyone heard of a piston that would be capable of this kind of velocity? it is a 7 lbs mass.

OR if you have another method of how to accelerate a mass with these conditions, id love to hear about it.



RE: Accelerating a Mass with pneumatics

Gunpowder. smile

Fe (IronX32)

RE: Accelerating a Mass with pneumatics

Pnuematics for motion control are typically not a good ideal.  Repeatablity and control using air (compressible gas).  If you want to accelerate a mass, maybe using a timing pulley and timing belt arrangement might be better.  This hooked to a motor with variable speed drive, might do the trick.  If you need more control and precision with acceleration then hook the system to a servo drive.


Richard Nornhold, PE

RE: Accelerating a Mass with pneumatics

A flywheel?

Since you will be accelerating faster than gravity you would not need to release only at the bottom of stroke.  I was thinking of a punch press design.  You may need the ram to quickly reverse stroke and get out of the way of any bounce.  Have the down stroke of the ram trigger a mechanical release of the object at begining of stroke.  Vary the speed of flywheel as needed to tweak impact velocity.

Or just cut a hole in the roof....

Barry Payne, Titular Despot Emeritus

RE: Accelerating a Mass with pneumatics

I'd just use a big compression spring with a pin release. Easy, adjustable (put a screw behind a plate at the top), and cheap.

"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." -Scott Adams

RE: Accelerating a Mass with pneumatics

Thanks all for the posts! Ill look into them further.

RE: Accelerating a Mass with pneumatics

Consider a simple lever arrangement.
Pin the lever at one end and locate a weight of ten times (or 100 times if this varies with the square ? ) at 10% of the lever length from the pin. This will produce a 10 g acceleration. Provide a strong "stop bar" at the end of the lever at the opposite end from the pin at the height tou require for the "free fall" to start.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close