×
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

Linkage pushrod mechanism design

Linkage pushrod mechanism design

Linkage pushrod mechanism design

(OP)
Hi,

I have what I think is a simple problem to solve but I just do not know the details of the correct way to do it. I need to connect a lever arm to a push-rod by rod end bearing similar to this https://www.ondrives.com/bem-05lh-ss.

My question is what kind of pin or fastener should be used to connect the two items without any play/float in the linkage? If the hole bores are 5mm should I size a Transition Fit 5mm pin between them and fasten retaining nuts to threaded ends? Should i used busings in the bore?

Thanks for any help you can give

Richard

RE: Linkage pushrod mechanism design

Why not ask the manufacturer?

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

RE: Linkage pushrod mechanism design

Any standard cylindrical part can be used. I have used shoulder bolts in the past. They are good, but only if applied correctly. If applied incorrectly they can easily break. I have also used a welded or press-fit dowel pin. You can also use a yoke arrangement where you capture the pin and rod end between two fixed features like a bolt head and nut, or retaining rings.

RE: Linkage pushrod mechanism design

Quote:

without any play/float in the linkage

Then by definition a transition fit will not do. You will need and interference fit.

RE: Linkage pushrod mechanism design

you want to screw the rod-end into a linkage member ?

the normal approach (at least in my business) is to tap the hole and to secure the rod-end with a jam nut. If you want to lock it down tight, add an anti-rotation device for the jam nut

another day in paradise, or is paradise one day closer ?

RE: Linkage pushrod mechanism design

Even if you get zero play in the connecting bolt, your race (especially Teflon lined as specified) will wear. Do you need zero play in both push and pull, or just in one direction?

RE: Linkage pushrod mechanism design

I assume the linkage needs to pivot with reasonably low effort once in a while.
Do you R-E-A-L-L-Y need zero clearance ?
0.002" radial clearance would not suffice?

How much force must these 5 mm pivot shafts endure?
Through how many degrees must the linkages pivot?
How may cycles?
What is the environment?

Possibilities I'd be considering, with the limited input you provided.
true, zero clearance
1 - those hinges made from thin metal plate. ( 90 degree motion or so )
2 - plastic "living" hinges. http://www.spencerindustries.com/index.cfm?pfile=P... ( 90 degree motion or so )
3 - axially preloaded tapered bushings ( full rotation )
4 - axially preloaded tapered roller bearings ( full rotation )
5 - axially preloaded ball bearings ( full rotation )

Low radial force required - castellated metal or plastic bushings that snap onto the shaft with negative clearance, but low radial force.

Preloaded ball and socket joints, hydraulically preloaded as done many millions of times as shown here -
http://grumpysperformance.com/oilpassage.jpg


RE: Linkage pushrod mechanism design

Clamp the spherical race of the rod end tightly between the inner faces of a lever arm clevis ears using a shear fit bolt. Torque the bolt so that there is sufficient clamped friction between the spherical inner race and clevis faces to ensure any rotational motion at this joint occurs at the spherical bearing race interface, rather than at the bolt.

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