Workbench mobility by mechanical cam

[Redlunn]

I'm sure you're all sick of looking at all the various attempts at making a workbench mobile,...but here's one more. My "optical breadboard" table is quite heavy and the bins only make it worse. I liked the stability of having it on solid feet but occasionally it would be nice to roll it out of the way. I looked at a number of other designs utilizing acme threads or hydraulic jacks but I wanted to go a different route here. My main criteria for success was fast acting and single point lift. I didn't want to walk around pumping on a jack on each side just to lift the table on casters. The solution I chose was to use a cam on a rotating shaft to apply a downward force on the casters, thus lifting the table. Spanning across the length of the table, between the bins and table top, is a 2" diameter tube. Welded to this tube are cams that engage a bolt head attached to a floating caster assembly. One cam and caster assembly on each end of the table but both operated by the same shaft. So, rotating the shaft 90 degrees will cause both ends of the table to lift and it can be maneuvered as needed. I have not measure the torque required to rotate the shaft but it is easily accomplished with one hand.

I'm pretty happy with how it turned out but I'm always open to potential improvements.



Here is the table resting on it's feet.


Here you can see the 2" tube below the table top.


This a closeup of the cam when not lifting.


And this is a closeup of the cam when lifting.


Yep, those feet are off the floor...


Here you can see the actuator handle at it's 90 degree lift position. Straight down is it's normal position when not lifting table.

Thanks for checking it out.

Redlunn

 

[Old Man Roger]

Pretty awesome.

 

[bullnerd]

Very cool, and nice table!

You should have just used the air bags! Run some lines, and quick connects and gauges and use a bicycle pump!

LOL, just kidding, very nice job.

 

[tarbellb]

This is SWEET!

I love all the different approaches to lifting a table, but this one seems really well executed and much more inline with what I would want to do.

What are those pads/pillows between the top and base? Pneumatic? Insulation?

Thanks for sharing.

Oh, how do you think those bolts are going to hold up with the cam action grinding on them, are they greased?

 

[joe49]

While not a fan of MacGyver tables, yours is a good idea.

 

[Bigblue&Goldie]

I have to ask, what is an "optical beadboard" used for?

 

[Redlunn]

I have to ask, what is an "optical beadboard" used for?

I believe it's intended purpose is for optics experiments. Like lasers and mirrors. The table is made out of a honeycomb structure that is supposed to be ultra rigid.

What are those pads/pillows between the top and base? Pneumatic? Insulation?

Oh, how do you think those bolts are going to hold up with the cam action grinding on them, are they greased?

The pads between the legs and base appear to be for vibration suppression. They don't serve much purpose at this time.
The bolts are 3/4" diameter and the cam is greased. I had considered a roller cam follower but opted for the simple solution. Time will tell but no signs of wear at this point.

 

[tarbellb]

It looks awesome, I am sure the cam system will hold up fine.

Thanks for sharing.

 

[gte718p]

I believe it's intended purpose is for optics experiments. Like lasers and mirrors. The table is made out of a honeycomb structure that is supposed to be ultra rigid.



Optical tables are awesome, though the prices new are insane. In addition to being very rigid, they have very good vibration isolation. You can also get them insanely flat. The good ones are lapped in addition to the grinding. I saw one advertised as +-.00001m over a km obviously the table is not a km long, but if it was it would not vary much.

 

[matt_i]

That's a great design, how did you machine (or fabricate) the two cams?

 

[Redlunn]

Optical tables are awesome, though the prices new are insane. In addition to being very rigid, they have very good vibration isolation. You can also get them insanely flat. The good ones are lapped in addition to the grinding. I saw one advertised as +-.00001m over a km obviously the table is not a km long, but if it was it would not vary much.

Yes, I'm sure a nerd somewhere cries every time I beat this table with a BFH. I was that nerd at first but I'm over it now.

 

[Redlunn]

That's a great design, how did you machine (or fabricate) the two cams?

Thanks! Cams were designed in Solidworks then cut on my homebrew CNC plasma table. Nothing super precise but it seems to do the job.