×
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

Hydraulic Piston twist

Hydraulic Piston twist

Hydraulic Piston twist

(OP)
If you have a clevis that is just screwed on and not locked, on the end of a piston rod. Could the rod twist and unscrew the clevis (the clevis can't rotate)?

RE: Hydraulic Piston twist

If there is nothing to prevent the piston from rotating then it is a possibility however slight.

RE: Hydraulic Piston twist

Most clevises that I have encountered are split and have a threaded fastener to cinch the internal threads tight around the external threads, reducing the risk of backoff.

I barely ever use them and haven't had one come apart yet.

RE: Hydraulic Piston twist

I have seen cylinder rods unscrew themselves.  This was mostly on high cycle lightly loaded applications.  I have never seen a large cylinder rod end that was not locked with a jam nut or a type of thread locking compound like Loctite.

Barry1961
 

RE: Hydraulic Piston twist

Pistons try to follow the hone helix when the seal is under high pressure. Locking threaded fasteners in a hydraulic cylinder application is difficult. Jam nuts and thread locking compounds are not the best choices, as they frequently fail. Welded pin mounts seem the best. If it must be threaded, a split nut clamped, or a large dowel pin through the shaft and clevis seem the best. The push and pull forces combined with side loads tend to make the threads move between each other.

RE: Hydraulic Piston twist

(OP)
Thanks guys, I'll lock it somehow

RE: Hydraulic Piston twist

Use a thread lock, typical in the oilfield.  Something like Bakerlok or equivalent would "glue" the mating pieces together.  You apply heat, like from a blow torch or equivalent to break them apart.

I've used this extensively in the field, never a problem.  The glue itself is like a Crazy Glue, so very strong.  You can pick up a small bottle at any fastener supplier, inexpensive and practical.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

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