What COTS parts would you like to see?

[Tal_Esh]

Didn't know it is being sold, greath news

[Mk.32]

Originally Posted by jwfoss

-4"x1.5" and 4"x2" Aluminum Wheels with 1/2" Hex Broach
-Anti-backdrive stage for VersaPlanetary
-Disc Brake set up with 1/2" Hex or "Standard" Sprocket Hole Pattern

Discs brake you want eh?
https://electricscooterparts.com/discbrakes.html

I learned that BRK-512 works with BRK-480L and has a hole pattern that is close enough to work with the AM 1.875in hole pattern with number 10s.

[jwfoss]

Originally Posted by Mk.32

Discs brake you want eh?
https://electricscooterparts.com/discbrakes.html

I learned that BRK-512 works with BRK-480L and has a hole pattern that is close enough to work with the AM 1.875in hole pattern with number 10s.

Thanks for the heads up, did you also buy the caliper from the same company? If so which one, and do you have any images of integration into your robot? Thanks!

[Monochron]

Originally Posted by jwfoss

Thanks for the heads up, did you also buy the caliper from the same company? If so which one, and do you have any images of integration into your robot? Thanks!

Seconding!

[Greg Needel]

Originally Posted by Monochron

Seconding!

We used a mechanical brake this year, and had good success integrating one like this onto the robot. https://www.ombwarehouse.com/univers...e-caliper.html


We actually just used a sprocket as the disk without problems.

[Brandon Holley]

Originally Posted by Kevin Ainsworth

Dido on the ratchet and pawl for a 1/2" hex bore. We modified McMaster ones for both our winch and climbing mechanism this year.

Boom.




-Brando

[Ryan Dognaux]

Originally Posted by Mk.32

Discs brake you want eh?
https://electricscooterparts.com/discbrakes.html

I learned that BRK-512 works with BRK-480L and has a hole pattern that is close enough to work with the AM 1.875in hole pattern with number 10s.

We've also used disc brakes for the past 2 seasons. It was extremely helpful in 2015 for holding our elevator's position without stalling motors.

I'm about 99% sure we purchased this kit from Amazon - https://www.amazon.com/Signswise-Mou...rds=disc+brake Came with 2 disc brakes and 2 caliper kits. Great for a practice bot and competition bot setup.

The hole pattern was close enough to get 3 or 4 bolts aligned to mount a 1/2" hex hub. We used a small pneumatic actuator to pull the caliper's brake cable, worked great. You can see a video of it here.

[Mk.32]

Originally Posted by jwfoss

Thanks for the heads up, did you also buy the caliper from the same company? If so which one, and do you have any images of integration into your robot? Thanks!

I have listed both model numbers for the disk and caliper: BRK-512 and BRK-480L. You should find both parts on the website. The caliper uses a regular old bike cable.

Heh.. ironically this was an happy accident. As I did not buy these parts for FRC but for a gokart I race at makerfaires (us mentors gotta have something to build in the off season). And I used AM tires for the front, and realized that everything lined up nicely so it saved me the trouble of making an adapter hub.

You can also make your own disks to if you have basic milling abilities, take piece of .09 flat stock and drill the holes you want into it. You do not need any of the fancy cutouts and speed holes/etc of the commercial disks. Just need the stock to be flat.

[Mike Schreiber]

Originally Posted by happyWobot

Yes I have. Generally I've been very pleased with the VP. Through 4 events they held together running a shooter that worked outside the robot perimeter. They took unbelievable punishment. But they have one potential flaw. We saw the shaft fly out of the VP twice this whole season. Mind you right before the second time the case was making a rattle we couldn't identify. It was trying to tell us something. And then it flew out during a match.

We eventually settled upon the theory that the C ring holding the shaft in place had become worn or weakened. We replaced the ring with one from a soare VP case when putting it back together and it went for another 2.5 events.

It was frustrating knowing that it could do that. For a case that disassembles so easily just didn't make sense that a better design that prevented that from happening could not have been used. But like others, I agree that the output end to the VP gearbox is severely underutilized from a design and function perspective. There is a lot of potential there. Longer shafts, angled output, greater variability of shaft lengths, etc. I could even imagine a U transfer case directing the output back towards the motor for space critical uses.

I've seen this occur because the snap ring is over stretched when being installed. It is easy to deform these if you're not careful. Don't open up your pliers too far, just the bare minimum to clear the spline, this should ensure a nice fit when they spring back.

[Michael Hill]

Originally Posted by Mark Sheridan

The spline is a separate piece. The shaft and spline are combined with a dutch key. I almost did this last season: Press out the shaft and insert a new one and drill in a new hole for the dutch key.

Do you have any pictures of this? I looked at our VP output shafts and couldn't find anything that resembled this. Maybe I'm just blind.

[Mark Sheridan]

Originally Posted by Michael Hill

Do you have any pictures of this? I looked at our VP output shafts and couldn't find anything that resembled this. Maybe I'm just blind.

http://www.vexrobotics.com/217-2894.html

You can see it in this picture. There are two dowel pins used as keys, thus making them dutch keys. 100% of mine look like this but our shafts were sourced from 2013, 2014 and 2015. Its not a published spec, so vex could have another revision that is not made this way. We found a way that avoided taking apart this feature, i am not sure how hard it is. I used the dutch key professionally as an emergency reinforcement of key way, they were not drilled straight so once the dowel pins were inserted, we knew it has really hard to take apart thus threw away the assembly when there was down time.

[Michael Hill]

Originally Posted by Mark Sheridan

http://www.vexrobotics.com/217-2894.html

You can see it in this picture. There are two dowel pins used as keys, thus making them dutch keys. 100% of mine look like this but our shafts were sourced from 2013, 2014 and 2015. Its not a published spec, so vex could have another revision that is not made this way. We found a way that avoided taking apart this feature, i am not sure how hard it is. I used the dutch key professionally as an emergency reinforcement of key way, they were not drilled straight so once the dowel pins were inserted, we knew it has really hard to take apart thus threw away the assembly when there was down time.

Wow, ours don't look like that at all. Our's have a continuous back side, but there's a small hole in the middle.

[Aren_Hill]

Originally Posted by Michael Hill

Wow, ours don't look like that at all. Our's have a continuous back side, but there's a small hole in the middle.

It does depend on the shaft, the 1/2" hex shaft does not have this as it is machined from solid, same for the 1/2" round. But the 3/8" and 8mm shafts are two piece units.

-Aren

[Michael Hill]

Originally Posted by Aren_Hill

It does depend on the shaft, the 1/2" hex shaft does not have this as it is machined from solid, same for the 1/2" round. But the 3/8" and 8mm shafts are two piece units.

-Aren

Makes sense. That's exactly what I was looking at. I think we've got an 8mm output shaft somewhere I'll have to check out. Thanks!

[DonRotolo]

tl;dr

A good elbow joint, using most any motor, light and under $400. That woud be a great COTS part.