Denso Window Motor Gear Box - Legal to use?

[itaipelles]

hi guys,
my team plans to use some kind of an elevator/lift for the robot for the frc 2012 rebound rumble.
to power the elevator, we plan to use a banebot RS-550.
the thing is, we really want to gear it down with a worm gear, so that the elevator won't go down unless the motor spins backwards.
we're quite low on budget this year, so we are searching for creative ideas for a worm gear for our banebot.
the best idea we've had so far, was to disassemble the denso window motor (it has 2 parts - the motor itself, and a 80:1 worm gear), and use its gear.
we did it, and successfully connected the banebot to the window motor gear!
it works very well, and we call it "The BaneDow Motor"

now, we are wondering, is it legal?
according to the blue box under rule 49:
"Note that for the Window motors and the AndyMark gearmotor, the gearboxes are considered integral to the motor, thus the motor may not be used without the gearbox."
On one hand, they say that the gearboxes are integral to the motors, and the motors are not to be modified,
but on the other hand, they only specifically say that the motor may not be used without the gearbox, while we plan to do the opposite - use the gearbox without the motor.

also, the blue box under rule 49 says:
"The intent of this rule is to maintain the maximum power level for each Robot"
logically thinking, all we want is a 80:1 worm gear, and we are low on budget. we do not hurt the intent of the rule, and not allowing us to use this gearbox will only make us buy a different one for a lot of money.

So, please help me!
is "The BaneDow Motor" legal?
Thanks a lot!!!
Itai Pelles,
Team 3316

[billbo911]

I'd say it's legal. But then again, I'm not the GDC. So I suggest you post the question on the official Q&A forum and get a definitive answer.

[dudefise]

We did something similar to this last year and we successfully passed inspections. However, I would recommend putting it on the Q & A for an official ruling. My interpretation, however, is that this rule refers to using the motor without the gearbox, rather than the other way around.

[JCharlton]

Do you still have any First Choice credits left? AndyMark had some lead screws which work well for linear motion, and won't backdrive. We ordered one but will be using a pneumatic cylinder instead. If there are veteran teams in your area they may have some spares, they were included in the KOP for many years.

[Tristan Lall]

Originally Posted by JCharlton

Do you still have any First Choice credits left? AndyMark had some lead screws which work well for linear motion, and won't backdrive. We ordered one but will be using a pneumatic cylinder instead. If there are veteran teams in your area they may have some spares, they were included in the KOP for many years.

Many of the ones in the past KOPs will spin under their own weight when supported by the lead screw nut (a sign of high efficiency). Also, the KOP lead screws aren't all the same—different ones have appeared in different years. If you want to resist backdriving, you'll need something else.

[Hawiian Cadder]

Worm gears don't actually prevent the motor from being back driven. In order to find how much force it will resist, take the resistance of the motor times the gear reduction divided by the efficiency of the gearbox. If this torque is greater than the rating for the gearbox be wary as it will shred the gears before the motor is back driven.

[Al Skierkiewicz]

The rule specifies that the motor and gearbox are one piece. They cannot be separated.

"Note that for the Window motors and the AndyMark gearmotor, the gearboxes are considered integral to the motor"

This is unlike the Globe motor where the gearbox was considered in some years, to be removable.

[apalrd]

In the past, we took a COTS Bosch window motor (nothing like it was ever in the KOP), took the actual motor off, and made an interface to a Fisher Price motor on the mill.

Since it used the US Car standard window motor interface, it was a drop in replacement for the Denso in terms of bolt pattern and shaft spline.

(unfortunately, I don't have a picture with me)