Dewalts Used Last year

[Xufer]

This year a few mentors and alumni from Team 521 Broke off and started a New team a few towns over.
Our machining capabilities are fairly limited and we are looking for a simple way Change gear ratios. The Nothing but Dewalts paper looks promising and we spoke of using them last year, but in the end decided against it. What i am wondering is how they faired in competition last year? I know many teams used them last year if you could explain any problems you had with construction or in competition that would be great.

Also has anyone thought about putting the new minibike cim into a dewalt deill transmission? If so was it successful?

Thanks a lot!
-The members of team 1470

[Jeff Pahl]

We used two of them last year, with the CIM motors. They were rock solid and are still working great after several months of demos and student "practice" with the robot. I highly recommend them!! The plate that goes between the yellow drill housing and the CIM to mount the whole thing is very easy to machine, you can get by with a drill press and a bandsaw as long as you lay the holes out accurately. However, machining the press-fit hole for the motor shaft in the existing Dewalt gear is not something to try with limited machining capabilities. Just plan on sending them out to be EDM cut.

We never did set them up to shift, the drivers seem to like them in 2nd so we just leave them there.

[Xufer]

I mostly worried about the servo shifting. That seems like a possible week point in the design.

A few years back i remember a team (i belive 177 bobcat robotics, i may be wrong) taking the drill motor housings and adapting the fischerprice motors to them. I belive they had a problem with the drills getting caught between 1st and 2nd.

Thank you.

[Richard Wallace]

931 built two NBD units with FP motors last year. One raised (rotated) the outboard section of our arm via a 2-stage sprocket system. The other was a spare.

We never needed the spare.

[Stu Bloom]

We used them last year and will definitely be using them again this year (for drivetrain, with CIM motors). Tremendously robust and relatively light weight WITH shift-on-the-fly capability.

I was also concerned about the servos being strong enough to shift these transmissions, but if you remove the detent clip under the shifting ring they work just fine.

Good Luck!!

[Joe Johnson]

I can say with confidence that these transmissions are FIRST-friendly.

We have just plain never had a failure.

I know of about 50 teams that use them. None have reported to me being unhappy with them. I would not/do not hesitate to recommend using them.

Joe J.

[Stu Bloom]

Also, for those interested, check my post HERE for more information/links and a source for the sometimes difficult-to-find parts you will need.

[Henry_Mareck]

we never had any problems with shifting, though we modified the shifter for only 1st and 2nd gear, never third. Worked great, defintley reccomend them. We have sent the sun gears off to be machined already(i think), and have already done the interface plates on our cnc mill for this year.

[Xufer]

Originally Posted by Henry_Mareck

we never had any problems with shifting, though we modified the shifter for only 1st and 2nd gear, never third. Worked great, defintley reccomend them. We have sent the sun gears off to be machined already(i think), and have already done the interface plates on our cnc mill for this year.

Im glad to hear these transmissions worked out so well for everyone i really hope we get to try them out this year.

[Xufer]

What is the estimated or actual weight of the Chippua + Dewalt package? Including the servo for shifting. but not including any out put gears/or sprockets.

[Bill_Hancoc]

what are some peoples suggestions for mounting a CIM-DeWalt combo to be chained to a single wheel?

Thanks for the help

[Xufer]

Originally Posted by Bill_Hancoc

what are some peoples suggestions for mounting a CIM-DeWalt combo to be chained to a single wheel?

Thanks for the help

See i was wondering about wether i want to put one on each wheel or combine the two first, but im not too sure about combining motors via chain. so i would also love to see some ideas.

[Joe Johnson]

Originally Posted by Xufer

See i was wondering about wether i want to put one on each wheel or combine the two first, but im not too sure about combining motors via chain. so i would also love to see some ideas.

There are other papers and threads on this topic, but here is my 2 cent again:

There is a very strong advantage to having a chain couple the 2 motors and the 2 (or 3 or more) wheels on each side: when a wheel if off the ground, the power from both motors is automatically diverted to the wheel (or wheels) that are still on the ground.

2 wheels each with its own motor with out a linkage such as chain between them saves a bit in weight and packaging (potentially), but when a robot rocks you back on your hind wheels during a pushing match, that wheel out in front that is off the ground is not doing you any good.

Joe J.