×
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

stainless tube sliding inside another stainless tube

stainless tube sliding inside another stainless tube

stainless tube sliding inside another stainless tube

(OP)
I have taken over a job where I need to have stainless tubes slide inside other stainless tubes for a marine ladder application. The guy that designed this up didn't do a very good job of thinking about it. The top flare interferes with the inside of the mating tube as well as you can see he just extruded it and shelled it which makes it expensive to mfg as drawn up.
The customer also wants to do some bushings.





I am looking for others thoughts about how to implement this. My initial thoughts are to put a swage in on the outside tube just below the flare at the end of the inside tube. This would act as the hard stop for loads that go on the ladder in the extended position.

When folding up the ladder and extending the ladder they want a some what smooth low effort feel. So I am thinking of doing a thin PTFE bushing down at the bottom stake on the inside of the outside tube and the stake would hopefully keep the bushing in place. The one on top could also be a stake with a piece of bushing material.

No tooling has been developed for this project. It will be mfg over in china.

RE: stainless tube sliding inside another stainless tube

Do the swaged areas of the tubes carry the person's weight from the bottom tread up to the top bracket? Not sure I'd trust that design for a 250 lb. person. I'd trust it even less if this is installed on a swaying, tipping, heeling/yawing boat in heavy seas, where one leg sees a lot more load than the other, and the angle of loading is shifting as much as 45 degrees from vertical. Far less after the first user hammered on the treads or the tubes to collapse the structure after its first extension, when the legs bound up because they weren't evenly fed into the upper tubes. Does this assembly have to pass a safety inspection, or get a UL or other safety rating for sale in the US or other state?

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