In the manner of the Lazy Susan what is a plausible means of power?
Any suggestions?
Are you asking about powering the turn of a lazy susan?
You can drive it with a belt, wrap the belt around the outer edge of the lazy susan, wrap the other end onto a well geared motor and you got yourself a powered lazy susan.
Yea that a really good idea, any other suggestions?
I’ve seen this in the 2006 Behind the Design book:
Take a small-ish motor, put a reasonably grippy wheel on it (or, better, on the gearbox), and plant said grippy wheel firmly on the part of the lazy susan you want to rotate.
We did this in Lunacy. Direct-driven window motor with (I believe) about a .5" diameter cylinder coming out of the shaft with something akin to sandpaper glued on. Also on the lazy-susan some grip-tape we bought from Lowe’s. We did have to lubricate the lazy-susan and make sure that no hardware would interfere with rotation, but this is a normal consideration.
This was several years ago on a different team that I work with now, so some of the specifications may be off but I think they are close.
I saw a video where a team lined the edge of the lazy susan with gear teeth. They placed a smaller gear meshed against it and powered it with a motor. It was able to run back and forth pretty well.
Our team used a large lazy susan bearing back in 2006. We mounted a polycarbonate plate on it around which was placed a timing belt turned by a pulley on our drive motor. We found that the lazy susan bearing did not take well to the side pressure necessary to turn the load we had on top. The metal of the bearing would open up a little, making the bearing run loose and taking the tension off the belt.
If I were using the bearing again, I think I would use a drive puck on one side with a couple of idlers on the other side to keep stress off the bearing itself.
Dr. Bob
Chairman’s Award is not about building the robot. Every team builds a robot.
This is what my team did in 2009.
2791 did this in 2009 with good success. They didn’t use the turret for autonomous so they just needed a few limit switches and it was good to go.
1714’s 2009 turret used a very large acetal plate gear for a turret. I would recommend that if your shop happens to have a massive, ventilated plastic laser cutter in it and you’ve done that sort of thing a hundred times before, but for most teams it’s out of reach.
Yep, that was us!
The top disc had a larger diameter than the bottom disc to leave room for the wheel to drive it. If your lazy susan has 2 of the same size discs, just add something to the top one to make it a larger diameter.
We custom built ours.
http://www.chiefdelphi.com/media/photos/33185
Ignore the motor up top as that was a shooter motor, and look at the one attached to the wheel on the lower left-ish side of the picture.
In Lunacy, we used one of these lazy susan bearings http://www.leevalley.com/en/wood/page.aspx?p=44014&cat=1,250,43298,43316 which are much better quality. We had to make some modifications to it and it did come on the way back to the pit after our first practice match when our bot fell off the wagon. We were able to find most of the ball bearings and put it back together. There’s a removable threaded plus which is used to put the balls in. Lesson learned - no running. It supported the weight of our tower, and tiltable 4 wheel shooter. It worked well until late last year when the race finally cracked. We cut a Gates belt apart and epoxied pop-riveted it to the circumference of the lazy susan and then used a window motor to drive it.
I like the machined lazy susan bearing, as opposed to the cheap stamped ones.
You could use a timing belt for the drive mechanism. With a small drive sprocket and large turret sprocket you would have a dramatic speed reduction & torque increase.
For very large sprockets you don’t need teeth completely around the perimeter. Any more than 6 teeth engagement at a time is redundant. Just make sure the sections that don’t have teeth have the same radius as the bottom point of the tooth.
Example (of course you would have a hollow hub):
https://lh3.googleusercontent.com/-hslfIQvSaw4/TxQaTxj_jtI/AAAAAAAAN1M/oEV8_KSwISs/s800/Partial%2520Teeth%25201.jpg
https://lh5.googleusercontent.com/-jr0RYWiWDPs/TxQax2xl91I/AAAAAAAAN1g/pfDVYHqYZvI/s800/Partial%2520Teeth%25202.jpg