Re: Window motor to toughbox?
 

A window motor driving a toughbox with the second stage of gearing removed would be just about right to run an arm.

We thought about it a while and decided to use a V belt and pulley system, driven by a window motor, with a latex tube supporting the weight of the arm. Seems to work so far....but this is the prototype, not the finished product. One interesting thing about using a window motor with a geared or chained connection to the arm, is that you have to remove the robot from the field after the match, and if the arm is pointing up it's hard to get the arm back down. The belt lets it slip. Adjusting the belt tension so it slips when you want, and not when you don't, can be tricky.

http://www.youtube.com/watch?v=3vY2_h2GBIs

Re: Window motor to toughbox?
 

I would really suggest testing different approaches to make the fp with gearbox work, what is the weight being held on the end of the arm? You could use counter-weights, springs, surgical tubing, etc... to help offset the weight of the arm. Since the tubes do not weigh very much most of your weight is the mechanism. Play around with different systems, this way you won't overheat your motor. :) You have it built already so make some modifications on it and actually test the performance.

Re: Window motor to toughbox?
 

That's a good suggestion. We made our arm with a piece sticking out the back, that we can attach surgical tubing to. The tubing pulls the back of the arm (past the pivot about 4 inches) downward, which lifts the other end of the arm up. With 8 strands (two loops wrapped twice around) it does the job. We made an easily adjustable lower anchor so we can change the tension quickly to balance it just right.

Re: Window motor to toughbox?
 

7 RPM is not that bad for an arm!

Re: Window motor to toughbox?
 

Yeah, every time you run into a problem brainstorm the simplest ways first. In my Mech. Engineering courses in college we learned, on day one, "KISS" (Keep It Simple Stupid) and it really sums it up. What is easier? Adding some tubing? or devising a whole new gearbox system?

But keep working you guys are still making good time :)

Re: Window motor to toughbox?
 

We had about 40 lbs on our cim/toughbox setup without a problem, but it will take experimentation with the FP. Definitely try it out and abuse it before you use it on the real bot if you do decide to try it. Better cook it now than in comp (hopefully it wont cook though) :rolleyes:

Re: Window motor to toughbox?
 

FP and CIM motors are very, very different in how they are built and how much stall current they can handle before overheating.

Re: Window motor to toughbox?
 

Ok, after more playing with the motors and gearboxes today, we figured out that window motors into the toughbox just wont happen.

Next thing were trying is two window motors powering a sprocket with 15 teeth, to a sprocket with something around 60 teeth. We have the 15 tooth sprocket, we just need to figure out what to use for the other one.

Any suggestions?

We can't machine our own stuff, so its whatever we can find..if we could just figure out a range of how many teeth on the bigger sprocket then we'd be good