×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

Wrap spring on rod - axial force calculation

Wrap spring on rod - axial force calculation

Wrap spring on rod - axial force calculation

(OP)
Hello everybody,

I want to use a wrap spring, pretensioned mounted on a rod, as a brake (to lock the sliding of the rod in axial direction. What should be the calculation approach for the capable axial locking force, depending on the interference between spring and rod, number or spring's coils, etc.? Any documentation I could use (idealy downloadable pdf file(s))?

Thank you in advance.
 

RE: Wrap spring on rod - axial force calculation

I have no knowledge of such use of helical spring for brakes or clutches. The wrap spring brake/clutch is ussually working for rotational braking because the friction between the coils and the shaft tends to decrease the inner diameter of the spring thereby increasing the gripping torque on the the rotating shaft.

When you will push the shaft linearily the spring inside coil diameter will increase (compressed spring diameter grows when loaded).

RE: Wrap spring on rod - axial force calculation

One consideration will be friction. Another consideration is once the spring is torqued around the rod and grip force is applied, you can quickly overstress the moment arm and exceed the yeild strength of the material. Since you are dealing in Bending stresses the % stress before yeild is quite higher. This solution may take some trial and error. Feel free to send me a drawing of our problem and I can possible help with your solution.

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!


Resources