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Posted by Ken Leung at 2/2/2001 1:05 AM EST


Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.


In Reply to: Van Door Motor
Posted by Brian on 2/1/2001 7:05 PM EST:



: Our team is attaching a 12 tooth gear to the van door motor. We have drilled a hole to attach it with a pin. The pin isn't the greatest thing every invented. Any ideas? Thanx

When you put pins on the Van Door shaft, you might want to watch out for the stress on those pins. Two years ago we had a giant arm rotating a basket 8 feet high, and we attached one spring pin on each motor, and they ended up breaking. We had to replace them with Titanium pins, and made it through the competition, until one of the pins broke a few months later.

Maybe you want to have two pins on a motor shaft instead of one... But be sure not to drill the two holes right across each other. Probably want to keep the pins apart a little bit. Using screws instead of the pin would work too. Just tap the hole and put the screw through the gear and into the shaft.

So last year we improve the attachment by using a key/keyway setup, just like the drill motor coupler new this year from small part, and it work extremely well. Never fail once through out the year. A key is basically a piece of square steel piece, like 1/8" x 1/8". Then the keyway is just a groove on the shaft and also the gear. On the shaft the groove is like 1/16" x 1/8", which is half the size of the key, while the other groove on the gear is the same size.

So when the gear fit onto the shaft, you rotate them to match the groove, and that's enough space for the key to slide in, and that basically lock the gear from free spinning on the shaft.

A third method is to simply weld the gear on the shaft.

Feel free to ask any questions.

-Ken Leung