Big Clumsy Cam Followers don't work for me
Big Clumsy Cam Followers don't work for me
(OP)
I am working on a design involving a cam and follower. The nearest approximation of the shape of the cam is an ellipse and the follower continuously rotates around the inside of this ellipse (it is an internal cam). The problem I have is that there is very little space to accommodate the follower, or to be more exact the motion envelope of the follower. I was thinking if I could line the internal surface of the Cam with ball bearings, or equivalent, then I wouold not have to use a follower with incorporated bearings thus allowing the assembly to be more compact. My question is has anyone ever seen anything like this done before. The problems I am having are, amongst others,:
a)How to maintain the ball bearings in position around the internal surface of the Cam
b)How to design a follower that will ride smoothly across the ball bearings and not create a "bumpy" effect
Any replies would be gratefully received
a)How to maintain the ball bearings in position around the internal surface of the Cam
b)How to design a follower that will ride smoothly across the ball bearings and not create a "bumpy" effect
Any replies would be gratefully received





RE: Big Clumsy Cam Followers don't work for me
INA Permaglide
Fill what's empty. Empty what's full. And scratch where it itches.
RE: Big Clumsy Cam Followers don't work for me
RE: Big Clumsy Cam Followers don't work for me
It may be possible to get this done with an external cam, rather than the slot cam you are using.
RE: Big Clumsy Cam Followers don't work for me
RE: Big Clumsy Cam Followers don't work for me
Do you really need the exact move profile you have in your design?
Can you move the cam to somewhere that is not so space limited?
An eccentric ball bearings like harmonic drives uses. With this the outer race would flex and provide the linear motion.
A linear ballscrew actuator and program the move profile.
A rack and pinion with eccentric drive.
A gear motor with crank and program the move profile.
Use two small cam followers.
Run a roller chain/kevlar belt around two sprockets in an ellipse and connect to chain/belt.
Run steel on bronze and call it a wear item.
Barry1961
RE: Big Clumsy Cam Followers don't work for me
As a general comment to others who do not get satisfactory answers here,try to be clearer in posing your problem at the very least. I know engineers sometimes have difficulty in this area, but do the best you can.
RE: Big Clumsy Cam Followers don't work for me
Bengy2
RE: Big Clumsy Cam Followers don't work for me
Good luck on this.
RE: Big Clumsy Cam Followers don't work for me
Barry1961 has made the point that when stuck with a "impossible" design problem try to stay open to totally different methods of doing it. I believe I have done this but still find no alternative which is adequate. I will produce a diagram and post it here in the coming days (maybe under a new thread). Maybe some fresh ideas will come from this.
Thanks to all for you help,
Bengy2
RE: Big Clumsy Cam Followers don't work for me
http://www.cunningham-ind.com/index.htm
RE: Big Clumsy Cam Followers don't work for me
Steven Fahey, CET