Window motor to toughbox?
 

We need some sort of motor/gearing system to lift our arm. Today we tried the fisher price with the gearbox, and it worked wonderfully except it doesn't stay put when you take the power off it, as in it can be forced to turn. So we want to try to attach two window motors into a toughbox that we used last year in our winch that pulled us up the tower.

Does anyone have any ways/suggestions to get the window motors to work with the thoughboxes? One suggestion we had was to take a hacksaw to the plastic on the shaft so you just have the bare metal. But then how does that attach to a gear?

Re: Window motor to toughbox?
 

Carefull with your hacksaw. The last time I took a close look at the window motors that shaft does not turn.
Bruce

Re: Window motor to toughbox?
 

we just chain drive a sprocket and get the gear ratio that we need by using different size sprockets. We sometimes have to use a second set of sprockets to step it down to the desired speed

Re: Window motor to toughbox?
 

sprocket between two adapters would be the simplest.

Re: Window motor to toughbox?
 

most toughbox gearsets are very slow, however, with the KOP box this year, it provides 18 ft-lbs, and rotates 90 deg in ~1 sec

Re: Window motor to toughbox?
 

Could you explain this? What adapters?

Re: Window motor to toughbox?
 

Sorry for the double, but my main reason for wanting to use a window motor is because they don't backdrive

if there was another way we could stop motors from doing this, such as FP through the FP gearbox, that would be amazing...

Re: Window motor to toughbox?
 

From the KOP, Top of page 15, part # Denso-6 : Coupler, Denso motor, black, injection molded plastic, 6 tooth

Re: Window motor to toughbox?
 

The motor adapters are for interfacing with the plastic output of the motors. They are black plastic disks with conical protrusions extending from one face and have a center bore that accepts a keyed shaft on the cone and a bolt circle on the disk.

Re: Window motor to toughbox?
 

take what he suggested, put a keyed bar between the 2 adapters to hold it snug.. and put a sprocket on the bar somewhere. That's what were doing for some max lift power.

Re: Window motor to toughbox?
 

We've attached a window motor to a CIMplebox for our arm, but we had to machine a keyed adapter shaft to go from the plastic window motor adapter to the small gear. It seems to be working quite well so far; the gear reduction produces an ideal rate of rotation and sufficient torque to lift our manipulator.

A chain-based system would work, but you still have to find a way to attach the sprocket to a gear. The KOP sprockets are just too narrow to fit over the adapter without modification.

Either system would require a lot of structural support, since the window motor adapter isn't firmly attached to the motor axle. Bearings on the axle are also a good idea, to prevent cantilevering.

Also, the metal shaft doesn't rotate, so cutting away the toothed plastic bit won't do you any good.

Re: Window motor to toughbox?
 

why dont use use code to put enough voltage on the fp to hold it in place, you'll have to fumble with the values a little bit to get it right, but its worked for us (offseason project). We did it with a cim on a toughbox though.

Re: Window motor to toughbox?
 

Couldn't you easily cook the motor if it needed a significant amount of torque to hold up?

Re: Window motor to toughbox?
 

You could use the FP(or a Banebots motor, if you were so inclined) through a gearbox to turn a worm that turned a worm gear, essentially making a big window motor.

Re: Window motor to toughbox?
 

I don't recommend you put a window motor in a toughbox for one reason. A window motor in a toughbox would be SLOW. Window motors have a free speed of 84RPM (already pretty slow) by themselves and gearing that down to the 12.75:1 gear ratio of a standard Toughbox would give you a free speed of 6.6 RPM and a speed of 3.1 RPM at nominal torque.

Why don't you just use the window motors by themselves instead? In the KOP you got adapters for the window motors so you can attach the motors directly to a 5/8" shaft. Plus window motors have more than enough power by themselves to move just about anything you can ask them to. Just make sure you don't cantilever the shaft

Also you don't need a gearbox for the window motors because they already have one. The metal silvery thing sticking out the side of the window motor is a motor and the black part is the gear box which houses the worm gear (the reason window motors won't back drive). Before you get any ideas no you can't modify the window motor by separating the gearbox from the motor like you can with the Fischer price motors. The gear box is considered to be intergal to the motor which means you modify the gear box you modify the motor, which is against the rules. If you want a more explanation of window motor modification see this thread

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