Chain Guard

[thesilence]

Is it required by the rules to have a chain guard covering a chain that runs at a low rpm (the chain is not on our drive train)?

Thanks in advance,
Bobby -Team 4601

[Jon Stratis]

R08:

ROBOT parts shall not be made from hazardous materials, be unsafe, cause an unsafe condition, or interfere with the operation of other ROBOTS.

Emphasis mine.

When looking at runs of chains, inspectors look at the possibility of injury more than anything else - there's no easier way to lose a finger than having a chain yank it through a sprocket. As far as that is concerned, speed isn't really much of a question. A slow moving chain and sprocket can cause damage just like a fast moving one. If at all possible, add a cover to it to make it safe!

[jvriezen]

Originally Posted by thesilence

Is it required by the rules to have a chain guard covering a chain that runs at a low rpm (the chain is not on our drive train)?

Thanks in advance,
Bobby -Team 4601

Will it draw blood if I have my finger stuck in there when it starts turning, or will it stall? Low RPM often means high torque.

There is no specific mention of chain guards anywhere in the rules as far as I know, but it falls under the more general rule about your robot not being 'unsafe'.

[thesilence]

The chain is on a PG71 motor (running at about 30% power through code), which has a 16.6 ft-lb stall torque. The chain itself turns a ramp that loads and then changes firing angle on our catapult launcher.

[FrankJ]

"Safe" is ultimately up the lead robot inspector. Generally speaking chain drives that are buried won't get questioned. Something that is exposed like on a manipulator that goes outside frame perimeter is going to get looked at a lot more closely.

[TheFrozenSlink]

Originally Posted by jvriezen

Will it draw blood if I have my finger stuck in there when it starts turning, or will it stall? Low RPM often means high torque.

Im no safety captain, but I would recommend not testing that.

[IVAN]

I have never seen a team be forced to put a chain guard on at any comp. I do know last year they had teams put on guards for their shooter wheels though i think that that was because those components on most robots were easily accessible and prone to mishaps

If you feel it is unsafe then you should probably add a guard if possible

[EricH]

Originally Posted by IVAN

I have never seen a team be forced to put a chain guard on at any comp.

I have. Try a belt run of something like 3-4 feet, ending with about 1' of chain, and covering the whole thing. I've seen that.

If there are spinning wheels, or spinning chain, and it's easy to get a finger simulator (3/4" dowel works well) in there, anticipate being asked to put a guard on.