pic: Fischer Price motor are very powerful

[Jay H 237]

So that's what a "sprocket cam" looks like!

Is that just from normal use, or did it bind/the movement was restricted somehow? I'll also guess that the gear wasn't hardened otherwise it would've snapped (or something else would've let go) instead of twisting like that.

[/Pyro]

I am confused about this picture. It looks as if the gear was designed that way. It appears to be bolted twice to an aluminum block that appears to be attatched to an arm. Some clarification would be nice.

[CrazyCarl461]

Originally Posted by /Pyro

Some clarification would be nice.

I'm sure the two tabs used to be collinear. The tremendous moments about each of the bolts caused them to slip from their fastening and swing around bringing the rather thin rim with them. It is an easy fix. Just extend each tab so that it goes all the way across. That way, there is one member that can take some shearing and tension forces instead of all off the torque being transferred right to the two bolts in the form of a giant force couple.

Make no mistake: The Fisher-Price motor is an absolute beast. So be careful when pocketing sprockets! Leave some steel to help you out.

-Carl

[Will Hanashiro]

Originally Posted by /Pyro

I am confused about this picture. It looks as if the gear was designed that way. It appears to be bolted twice to an aluminum block that appears to be attatched to an arm. Some clarification would be nice.

this is what happened to our arm (322) durring one of our earlier attempts to hang. this particular sprocket wasnt directly connected to the fishers, but to two window motors that control our wrist. we tried to hang with our wrist slightly bent, and because window motors lock in place, the sprocket gave into the weight of a 130 lbs bot trying to hang. gravity tried to straighten the wrist, and the motors tried to hold the wrist in place, and crunch... there goes our sproket. ...but yea, it was the fishers that lifted the robot up to begin with...

Originally Posted by /CrazyCarl461

I'm sure the two tabs used to be collinear. The tremendous moments about each of the bolts caused them to slip from their fastening and swing around bringing the rather thin rim with them.

yep that pretty much what happened.

[Bduggan04]

We have similar drive sprockets from last year, only it bent into a triangle because it had three mounting points. We learned Our lesson though, leave a ring around the center when you lighten sprokets.

[Code\\Pilot]

one of our f-p motors got burned in the quarter finals, so we were not able to hang, they were powerful, but get too much heat in direct pulling.
So we lost 50 points and the chance to go to the semi finals.