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

Linear guide selection

Linear guide selection

Linear guide selection

I am developing a lifting mechanism for which I need to know the linear guide selection procedure along with the load calculations

RE: Linear guide selection

There is no general procedure or set of calculations for plug-and-chug of arbitrary mechanisms.

You might be able to get help here if you specify the geometry of the mechanism, including link lengths, stroke, weight of the object being lifted, and desired cycle time.

Mike Halloran
Pembroke Pines, FL, USA

RE: Linear guide selection

Linear bearing manufacturers publish calculation guides for sizing their rails properly. Whose rails have you put in your model?

RE: Linear guide selection

Your mechanism appears to be a pair of columns, each fitted with a cantilevered shaft that rises under power. The shaft ends are stubs that fit into a reel carrying 6 tonnes of something, that is unwound passively at up to 70 ipm or fpm for ?pm.
The stubs engage the reels by means of a mechanism that may be mechanical or hydraulic the moves the columns toward or away from each other.
The linear guides carry the bending moment from the cantilevered shafts holding the reel ends, plus whatever loads might accrue from misalignment of the columns from their drawn position.
Is that about right?

- The tension brake looks a bit small for continuous duty, but ~ok if it's a lock/park brake.
- It will need a guard to protect personnel from contact or burns.
- I hope there is some mechanism or structure, not shown, keeping the columns in good alignment.
- If only the span adjusting mechanism carries the moments between them, it may have severe stiction problems, and the allowed misalignment and resulting moments will severely tax the linear guides.
- Any equations you develop for guide selection must include misalignment, which basically means it has to include the stiffness of the entire combined hoist structure.

All of the roll handling equipment, which this basically is, that I have ever seen does not include linear guides or sliding ways or any such friction- susceptible component.
Most of them comprised frames cut from very sturdy plate connected with very sturdy tie-bars or shafts, and accomplished movement by means of rotation, not translation.
Hinges were typically easily replaceable mounted bearings bolted to frames, or replaceable bushings inserted in bushing holders welded to plates, or some similar arrangement that could be repaired in minutes.

Mike Halloran
Pembroke Pines, FL, USA

RE: Linear guide selection

Thank you for the help

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