×
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

Heart Shaped Box Cam
3

Heart Shaped Box Cam

Heart Shaped Box Cam

(OP)
Hi all, I'm trying to use a box design heart shaped cam to obtain a uniform velocity profile in traversing motion (see attachment) the problem is the cam jams in the dip, i've tried making other versions of the cam without the dip but then it just gets stuck in the new section.

The material is laser cutter acrylic (ok maybe not brilliant for friction but its convenient!)

RE: Heart Shaped Box Cam

What is the follower, how is its motion constrained, what is the radius of the follower "tip" relative to the slot width?  Can you live without the follower dropping into the notch?  Try making the inside of the notch have a radius larger than the follower tip.

RE: Heart Shaped Box Cam

I think you have a pressure angle problem in 'the dip'.
To resolve it, you need to make the base circle bigger, i.e. move the dip farther away from the center.  That may in turn force you to use a larger blank or a smaller stroke.
 

Mike Halloran
Pembroke Pines, FL, USA

RE: Heart Shaped Box Cam

(OP)
btrueblood:
the slot is 3mm wide and the inside of it varies from 5mm from the centre of the cam to 45mm. The follower is just a bar with a pin in the slot (clearance fit). The bar is also constrained to move in one place as it passes through a slot.

MikeHalloran:
this looks like good advice, moving the slot outwards by 5mm makes a lot of difference! Thanks

RE: Heart Shaped Box Cam

a suggestion to improve the design would be to have a roller at the pin, rather than a fixed pin, especially with plastic as the base material for the cam.  (It almost looks like an obround at the end of the bar..)

RE: Heart Shaped Box Cam

(OP)
Ah yes, the one we actually manufactured is round :)

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