Number of FP Motors
 

When we were designing I remember someone telling me we were limited to two fisher price motors. Now I'm going through the rules and I can't see anything that limits using fisher price motors. Am I missing it??

Also, If anyone can help me think of a way to speed up our mechanism that currently is using a globe motor, the standard gearbox and the gates belting that came in the kit, I would appreciate it.

Re: Number of FP Motors
 

I dont know where the rule is (prob in KoP section), but you are only permitted 2 FPs.
EDIT: It is listed in the KoP Checklist, as 2 motors. I am 100% positive you are only permitted 2 FPs.

Unfortunately, I havent used those belts and stuff in the kit before, so I cant help you there.

Re: Number of FP Motors
 

You got 2 in the KOP so you can use 2, no more than that.

I'm probably not the best person to answer your question regarding globes, but I think I can ask some questions that may help others answer it better.

1. What are the "bands in the kit"? The surgical tubing bands? The Gates belts?
2. Could you gear it differently? If using the gates belts, use different size pulleys on one end or the other?
3. What other motors do you have available (or which ones are already on your robot, whichever is easier)
4. What does the globe interface to, a sprocket, a pulley, a spool, etc.?

Re: Number of FP Motors
 

sorry for the lack of detail, my head hurts and I can't get a vivid picture of our robot in my head, and I can't remember part names very well

1. the Gates belts
2. We could try that If I remember right we have the smaller pulleys on the motor
3. we've used all 4 CIMs and 2 FPs
4. I think it's a pulley it came in the kit with the gates belts

Re: Number of FP Motors
 

Try using a banebots RS550 motor. There are a whole selection of gearboxes
. If you are currently at a regional and cant order one, ask other teams what banebot gearboxes they have

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buy different pulleys? (you can get them on McMaster, they're called timing belt pulleys)

Re: Number of FP Motors
 

one other option is to remove the gearbox on the globe and replace it with a modified banebots gearbox or modified dewalt gearbox or modified fp am planetary gearbox. This isnt a simple fix but despite to many peoples knowledge the globe motor is actually a pretty useful motor once the gearbox is removed. i beleive its around 11000 rpm. however i am not 100% sure this is legal but i see no specific reason why it wouldnt because your not modifing the motor just the gearbox. we are currently facing a similar issue with our robot but we still have the two fp to use if we need too.

Mcmaster doesnt sell the same kind of belt as gates belt in the kit . Since gates isnt a distributer, we got our extra belts from motion industrials who were very helpful and provided a product that was not stocked at there location the same day.

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Our team actually disassembled the globe motor transmission and took out a stage. We started out using these for our rollers to grab the ball, but they were too slow. Upon the removal of a stage, they are much faster and work very well for their purpose

Re: Number of FP Motors
 

Now I'm curious, who has used a Banebots gearbox on a Globe motor before? Is it as simple as pressing on a Banebots pinion, and screwing it together?

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How hard was this? What do you do? Is it possible to do at a regional without any machining?

Re: Number of FP Motors
 

Removing a stage is going to require shortening the ring gear on the outside of the transmission or removing the planet gears of a stage and locking the Sun/Carrier of one stage to a later stage. Neither is incredibly difficult, but it will take some time. The important thing to remember however is that this isn't going to net you any increase in power. Your mechanism will move something like 3-5 times faster (I haven't looked at the guts of a globe yet) but it will also only provide one-third to one fifth as much torque. You might have better luck speeding up your mechanism by attaching a banebots RS-550 or RS-540 to it, if you have them available. if you're using all 4 CIMS, 2 FPs, and both BBs, then you've effectively exhausted your supply of high powered motors and you'll simply be left with globes, window lifts, etc. However, if I recall the progression of motors correctly, the van door motor often ranks just a bit higher than the globe for power.

Re: Number of FP Motors
 

The team I used to work with did this. All we did was mill off a stage on the ring gear (the casing), and index 3 holes into the casing. Pull a stage out, slap it back together, three screws/roll pins in, and you've got a 400rpm Globe motor. Quite useful, actually.

Re: Number of FP Motors
 

We know about the loss in torque.

294 designed a 2.5" roller to to be driven with a belt reduction. they now realized that is a lot slower than it should be (considering on 973 we have them 1:1 to a 5" roller) they want to fix it. They don't have the belt available to switch ratios, and can't simple switch the two pulleys.

We/they have 3-4 globes to try this out on and if we can find a way to do it at the regional it'd be the easiest way to fix this issue.

Re: Number of FP Motors
 

Adam,

Removing a gear stage is probably your best bet, then. The smartest move would be to remove a stage and have the machine shop mill or lathe down the ring gear to make it shorter. The quickest way, however, would be to remove the planets from a stage and weld that stage's sun gear to that stage's planet carrier/ the next stage's sun gear. As long as you clamp everything up straight and true, this should work just fine. If you've got a Globe to burn, I'd try this first for a quick fix.

Re: Number of FP Motors
 

We have a spare Globe motor lying around our shop somewhere that I'll take a look at next time I'm in there. Can anyone elaborate on exactly how to take out out a stage without welding, milling, or anything that uses anything more than basically hand tools?

Re: Number of FP Motors
 

We dealt with that issue a couple of years ago. We milled down the casing on the gearbox of the globe by .25". We then pulled out the one level of planetary gears and increased the speed to something like 450rpm if I remember correctly. We did all the stats on it and have it in the shop somewhere. You do lose the proportional amount of torque however.

Re: Number of FP Motors
 

A few mentors on 254/968 decided welding the two stages and grinding off the gears would be a good method. They did it to one of their own, but didn't end up using it so they just let us use it. Worked out great for us and it only took the Ames Fabricator 20-30 minutes.

Re: Number of FP Motors
 

How do I remove the gearbox, I just got into our shop and can't find any way of taking out the pins holding it on

Re: Number of FP Motors
 

You have to press the pins into the body of the gearbox. You will feel them release/drop in when they get deep enough. Then it is just a matter of pulling them apart (should not require any force)

Re: Number of FP Motors
 

Andy,

I can't think of any sane way of dropping a stage without welding, milling or some such. If you're in a real crunch, I'd just make all the preparations for welding two stages together and plan on being first in line at the Machine Shop on Thursday morning. I suppose if you're attempting this on the stage right out of the motor then you could try degreasing the pinion on the motor and the carrier above it and fusing them with JB-Weld or some industrial strength metal-metal epoxy, but I wouldn't want to think of that as more than a temporary solution, to be replaced with a more permanent solution when you have access to a welder. You might have more success at it if you try this with the next stage up from the motor and simply degrease the gears and fill the entire stage with JB-Weld or some such, and then dremel off the teeth of the planet gears and any excess JB weld so the whole mish-mash spins freely inside the ring gear. This would atleast spread out the load a fair piece. That's the only method I can think of aside from hack/chopsawing the ring gear to length or mechanically munging up the planets so they don't spin and stay fixed around the sun.

Re: Number of FP Motors
 

we've tried pushing out the pins and drilling them out, we've got them almost all the way out but theres something right at the end that is stopping us. Any more suggestions on how to get these pins out.

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They are quite easy to push out with a punch (even a centerpunch or drill bit). They fall into the gearbox at first, but if you then push them too far after they are already free they can jam into the guts. We had that happen to one and it was a royal pain.

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well, we ended up drilling out the pins and we'll probably tap them and use set screws to hold the gearbox on. We are most likely going with the welding method but we plan on preparing the other one just in case the weld breaks.

Re: Number of FP Motors
 

Just remember to weld the stage closest to the motor that you can, since that's under the least load. If you can assemble things such that there's still a few planets in place but your welder can still tack the stages together, it'll help keep things aligned and reduce binding in your final assembly.

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That's whats they did at SD. They welded the planets on the removed stage in place, and ground off the outer teeth.

Re: Number of FP Motors
 

That's probably a better option unless you need weight or don't have access to a grinder.

Re: Number of FP Motors
 

I just want to clarify about something we just did. We took the gear that is on the motor (sun gear?) and welded it to the plate with the sun gear of the next stage. We removed the first stage's planetary gears altogether. Did we do everything alright?

Re: Number of FP Motors
 

Provided everything is properly aligned, that will work fine. Just make sure everything runs smoothly when it's all reassembled.

Re: Number of FP Motors
 

We used JB-weld the entire time at silicon valley and it didn't break the entire three days.

Thank you everyone for the help

Re: Number of FP Motors
 

Hah, we have had a bad experience with JB weld recently. The 4-40 threading of one our fisher price motors got stripped. We dirlled it out and replaced it with 6-32 threading, but there wasn't enough tapped depth to work at all. So we ended up JB-welding it to the andymark planetary gearbox, which worked until it snapped of in Portland. We then replaced the JB weld with more JB weld, and epoxy on the outside, which didn't work at all. Then we put 8-32 bolts in to prevent the motor from spinning around, and proceeded to secure it in place with large amounts of hot glue and zip ties. We subsequently bought a handful of fisherprice motors from ifi, and a new gearbox from andymark, and replaced it all at SVR. (phew)

Back on topic, team 100 originally used globes on their accumulating mechanism (rollers on top and bottom). At portland it was rather slow, so they replaced it at SVR with the banebots motors, (I think with small banebots gearboxes as well). We asked them about it and they said it delivered just as much torque while being twice as fast. They were #1 seed, and went on to win SVR as the competition's best hurdler.

Re: Number of FP Motors
 

How did you JB Weld the motor pinion to the first planetary stage and make sure everything was concentric? I'm trying to do this with one of our globe motors now, and was going to leave the first stage planetary gears in for concentricity alignment purposes, and then just dremel off the outer teeth so they don't mesh with the ring gear.

Re: Number of FP Motors
 

Richard,

57 had this done at LSR by the welder. Twice. We had an extra globe about, so we laid a degreased first planetary stage on top of the pinion and had him tack the gears in place from the top side, then grinding the outsides of the planets off and grinding the top of the carrier smooth. Grounding through the globe chassis wasn't particularly nice to it, thus the having extra globes. We haven't had a chance to run with it yet, but it looks fairly promising. Also, don't lose the washer you need between that stage's planets and the motor face. One of the students assembled one without that and it wasn't very happy with him.

Re: Number of FP Motors
 

is there any chance to do this to a globe motor without having to weld or mill or lathe???

We don't have those tools, and have run into the same problem as previously mentioned.

Re: Number of FP Motors
 

I'm using JB Weld (a strong form of epoxy for metal/metal contact), which you can get at any local hardware store for $5 or so.

According to Andy L (a little further up in this thread), it was strong enough for him. Mine is still drying right now, so I'll let you know how it holds up when it's done.

Re: Number of FP Motors
 

I believe you can pull it off with just JB Weld or a similar metal filled epoxy. It would be easiest to degrease the first and second stages and JB Weld them together with the planet gears in place for alignment, then grind off the outside teeth of the now frozen planet gears. I as I understand the gearings, this would give you approximately 5.5 times more speed with the requisite drop in torque. I'm a little antsy about this mod because that stage could be under as much as 7 in-lbs of torque. It's not a whole lot if you get the parts well cleaned and bonded, but I don't know if the JB Weld will hold up under it with poor bonding.

Better would be if you could JB Weld the first planetary stage to its sun gear, or atleast fix the first stage's planet gears in place with JB Weld. I think this would require a little more care, but the first stage is dealing with lower torques , so I think it would hold up better. Plus it's only a ~3.8x change in speed and torque, which might suit you better.

Re: Number of FP Motors
 

We removed the planetaries
Generously applied JB Weld
Put the gears together(Sun and plate thingy)
Put the motor back in the gearbox and the planetarys of the next stage put it in the right place