pic: what do you think?

[CD47-Bot]

loading photo ...

[sburro]

what do you think of this design?

[JVN]

How will you get the pneumatic to go to 3 different positions?

[sburro]

Originally Posted by JVN

How will you get the pneumatic to go to 3 different positions?

I do not know as of now. It is a design in the workings.

[Madison]

Presumably, the output is the rightmost shaft? How do the three center gears interface with the output shaft?

[patrickrd]

Looks good to me You just need to figure out a way to get the piston to stop mid-stroke... Maybe two pistons in series?? (don't know if anybody's every tried that ). There's probably quite a few clever mechanisms to do the trick.

- Patrick

[Tom Bottiglieri]

Originally Posted by patrickrd

Looks good to me You just need to figure out a way to get the piston to stop mid-stroke... Maybe two pistons in series?? (don't know if anybody's every tried that ). There's probably quite a few clever mechanisms to do the trick.

- Patrick

with this would you have 4 possible positions? Or 3? (While the primary cylinder is in, and the secondary cylinder is in, it is in stage 1. When the primary is in and the secondary is extended it is in stage 2. When the primary is extended and the secondary is in it is also in stage 2. When both are extended it is in stage 3)

[ngreen]

Originally Posted by patrickrd

Looks good to me You just need to figure out a way to get the piston to stop mid-stroke... Maybe two pistons in series?? (don't know if anybody's every tried that ). There's probably quite a few clever mechanisms to do the trick.

- Patrick

I would use a single and double solenoid(multi-positioning pnuematics) with three magnectic reed switches to stop you at the correct positions.

I would presume this would work quite well. I'm not as familiar with the programming side of it but it seems to me that this could be done.

[FotoPlasma]

Originally Posted by ngreen

I would use a single and double solenoid(multi-positioning pnuematics) with three magnectic reed switches to stop you at the correct positions.

If you use hardstops with the actuator, you'd only need one (max 2 for hysteresis) magnetic sensor.

[ngreen]

Yeah you could do it with one, with three I think you could know what position you were in easier (maybe not, I know you can still tell with one but three would easily tell you where you are) to make it into a automatic shifting system.

[JVN]

Seems like after all that hassle, it would just be easier to do a 4-speed similar to 33, or 968. (I'm especially partial to 968, but it is more difficult to manufacture than 33's).

Then again, I've found no need for more than 2 speeds.
You can get along fine with just 2, more is overkill.

John

[Tom Bottiglieri]

Originally Posted by JVN

Seems like after all that hassle, it would just be easier to do a 4-speed similar to 33, or 968. (I'm especially partial to 968, but it is more difficult to manufacture than 33's).

Then again, I've found no need for more than 2 speeds.
You can get along fine with just 2, more is overkill.

John

Well If you go for 2 speeds, your probably going to have a manual tranny set up where the driver switches speeds as needed. Going more than 2 implies you are going to have an automatic that switches accoring to speed and load. (See: Team 33)

Either one works, but a 4 speed gives a hungry programmer more to work on

[RogerR]

before you take my advice, realize that i'm not an expert (yet... )

it would apearr that there isn't enough space between the gears that are being shifted. i would say you need at least double the face width of the stationary
gears, otherwise you would end up engaging two different gearsets in mid-shift.

then again, i didn't see anything saying that this drawing was to scale, so this might be a non issue.

[Veselin Kolev]

Here's what I think.
If you want to just go for the design, meaning make it even though you probably will never use it, awsome. I think you're just going for a challenge, which is great. As for the mechanical part of it...

Sure, it looks like it'll work and all, if you get the right gear ratios, etc... but I myself have 2 "major"issues with this form of 3 speed. You notice that the spacing on the 3rd gear is a lot larger than for the first 2 gears. That is necesary to clear the first two from engaging, but it eats up space. Second, you are literally using the gear teeth as a shifting medium. Sure, cars do it too, but cars have syncros. Sure, other teams do it a lot, but I look at their gears by the end of the season and they are worn out a lot. For robotics purposes, sure it works. For anything else, I would look for a different method.
If you get a flexible coupler on the output shaft of this transmission so it takes the forces of shifting, your gears will probably be fine. Just look up "lovejoy" couplers online if you want an example of one.

If you're interested in slick transmissions, check out the white paper on the Technokats 2003 tranny. It's a two speed, but, as we've seen from other teams, it can be modified to be much more.

Other than that, this concept can work easily. Cool idea!

[Phil 33]

Are there any pictures/specifications about the killker bees transmission.

The design is being drawn up in CAD, and the code to make the transmission automated is being perfected. Before next season however, we will have CAD drawings, code, design details, etc.

i think that this might be problematic when it comes to meshing the gears

We had almost no problems with this. As Andy said, take the spot where the gears fit together perfectly, and move the center of the shafts apart 0.0015'' and its enough to allow the gears to mesh nicely. I believe we also originally filed the edges of the gears a bit to make them mesh a little better. Also, be sure to heat treat the steel gears to harden them which will reduce grinding. Making the gears a bit wider so they have more contact surface area also helps some.