Fisher Price Gearbox
 

My team is interested in using the Fisher Price Gearbox to raise our arm. The only problem is that we don't know of any way to connect the gearbox to a sprocket that will run the chain to the gear on the pivot point of the arm. Are sprockets that would work with #35 chains sold? Or is there some kind of work-around?

For this plan, would I have to find a way to make them myself?

Re: Fisher Price Gearbox
 

Get some octogon stock that will fit tightly into the white output part on the FP tranny. Put a hose clamp around the outside of the white part. You now have something you can bolt into or put a shaft with keyway into. Your location is Los Angeles but I don't recognize the team number. If you can get to Hermosa Beach I can show you what we have done over the years.

BTW we stole the above idea from Kingman (team 60) years ago. The only time we had a problem was when a programmer (who shall remain nameless) left our arm against a hard stop when testing a new program version. Of course the motor went the "wrong" way and I wound up rebuilding an FP tranny. Fortunately we had several around.

Re: Fisher Price Gearbox
 

I just did a casual search of McMaster-Carr for octagon stock, and I seem to be batting zero. Where does one go to get octagon stock?

Re: Fisher Price Gearbox
 

I can vouch for this method as well. used in 04/05.

Also, cough * Joe Ross* cough

Re: Fisher Price Gearbox
 

McMaster sells it up to 2" page 3510

Re: Fisher Price Gearbox
 

Thanks. I understand what you're saying about how to do this, I'm just wondering where I'll be able to get the part (octagon stock, that is). I couldn't find anything on google, and my team doesn't really have the resources to manufacture something like this (no CNC machine or anything). Do you have the link to a place that sells/makes this type of piece?

EDIT:

I went to that site but I only see hexagonal bars. Could you be more specific? thanks.

Re: Fisher Price Gearbox
 

I couldn't find any either and I checked the usual suspects.

I guess we just made our octogon pieces. They are not high precision. The way we mount the FP gearboxes has lots of slop. The ones we made were 1" or 1 1/2" thick. You could machine them out of square stock if you have a mill.

If not you can use a band saw. Lay out an octogon of the proper size on the aluminum plate. Cut the shape out wit a band saw, taking care to make clean cuts. It is OK to be slightly oversize. Then file down to the layout marks. If you really have to, you could probably use a hacksaw, but it is hard to get a good cut that way.

Re: Fisher Price Gearbox
 

I guess I don't understand what you mean? They have hexagon bars in the correct size. What are you looking for?

Re: Fisher Price Gearbox
 

Fisher Price sells a hub that fts over the white piece. It is flat on one side and with a spacer you can bolt a sprocket to it. We ran a 1/2" shaft through the middle and made the spacer fit to that. You'll need to put a collar on the shaft to keep the hub from coming off the white piece.We did it on our 2005 robot. We used two FP transmission/motors facing each other with the sprocket between them. I couldn' find a good picture of the assembly. If you need one PM me and I;ll see if I can get a picture in the next couple of days. (yes! we still have all of our previous years robots around!)

Good luck!

Re: Fisher Price Gearbox
 

Here's a pic showing both methods mentioned on this thread...

http://www.travisusd.k12.ca.us/vande...n/DSC00303.JPG

On the top FP Transmission we're using an octogon adapter with a hose clamp that we made back in 2003.
On the bottom Transmisison we've used the plastic coupler that FP sells (used to come in the kit) and acually broached it and stuck a shaft through it. We have also bolted plate sprockets directly onto that plastic coupler.

BTW: That setup was all for prototyping purposes only.

Re: Fisher Price Gearbox
 

Here is a link to a picture of the hub!
http://www.householdappliance.com/on...4602249big.jpg
Check out part # 33 on this drawing.
http://www.householdappliance.com/do...08C7A42169.pdf
This is a link to a place that sells the parts.
http://www.householdappliance.com/po...gearboxes.html

Re: Fisher Price Gearbox
 

they want octagonal bars.

Re: Fisher Price Gearbox
 

I NEED HELP!!!!!!
 

I WANT TO KNOW ARE THE BUMPERS INCLUDED IN THE MEASURMENTS OF THE ROBOT?:confused:

Re: Fisher Price Gearbox
 

I found myself in a similar conundrum today. Thankfully I found this thread. I was able to rough-cut half inch nylon (or whatever the plastic is) and then using a belt sander and patience, get a rough octagon that fits snuggly in the FP gearbox.

Then there's getting the hole in the middle. That's the real pain, if you do it rough like I did. I tried using an old FP gearbox (we have a dozen, I think) as a guide for the hole. Didn't work too well, wobbles a lot and I had an off center hole. I also had the entire gearbox swinging around when it got jammed on the 15/32" drill bit that was in the drill press. :ahh:

I'm glad that I, a mentor, didn't delegate that task.

I'm going to redo both octagons it using a turntable that mounts on the mill's table. (drilling the center hole first)