Easiest/most economical way to build a pickup roller

[jlian]

We were thinking about using a hex shaft with wheels. However, we're not too sure what the best way is to secure the wheels on the shaft (hex shaft collars + hex hubs seem a bit too involved/expensive)

I was looking at Team O-RYAN's Ri3D video and the wheels seem to be secured without much setup.

We are a rookie team so we don't have a lot of resources.. Nor do we have scrap material from previous years. Anything we want to build we would have to order.

Is there an easy way to build this pickup?

[androb4]

Originally Posted by jlian

We were thinking about using a hex shaft with wheels. However, we're not too sure what the best way is to secure the wheels on the shaft (hex shaft collars + hex hubs seem a bit too involved/expensive)

I was looking at Team O-RYAN's Ri3D video and the wheels seem to be secured without much setup.

We are a rookie team so we don't have a lot of resources.. Nor do we have scrap material from previous years. Anything we want to build we would have to order.

Is there an easy way to build this pickup?

They built their intake using very basic parts. To build an intake like theirs, I would pickup some aluminum square tubing from a local hardware store, shaft (preferably hex shaft from VEX), shaft collars, wheels that fit the shaft, bearings that fit the shaft, sprockets, chain, and a geared motor.
You can PROBABLY do without bearings

[Mike Starke]

Hex shaft collars are a great way to go! What wheels are you using? Some wheels come with a hex built in, if not, a hex VersaHub from VEXpro would be a great fit!

[wilsonmw04]

Originally Posted by Mike Starke

Some wheels come with a hex built in,

Check out Banebot wheels. They are cheap and made to take hex shafts. or AM star tube.


http://www.andymark.com/product-p/am...m?1=1&CartID=0

http://banebots.com/c/WHB-WM-HS4

[BBray_T1296]

Originally Posted by wilsonmw04

Check out Banebot wheels. They are cheap and made to take hex shafts. or AM star tube.


http://www.andymark.com/product-p/am...m?1=1&CartID=0

http://banebots.com/c/WHB-WM-HS4

It's called a Churro Tube by the way

[pfreivald]

Hex shaft, a couple of hex bearings, two Banebots wheels, and some PVC to use as spacers to hold the wheels in place--it'll last you all season and is about as cheap as a mechanism gets!

[geomapguy]

Originally Posted by pfreivald

some PVC to use as spacers to hold the wheels in place--

Still pretty cheap to get hex shaft collar clamps from Vex too!!

[jlian]

So I should get

- Aluminum tubing from local aluminum shop (http://www.alustock.ca/Square-Tube-SC-1x0.125-AMR1465)

- AndyMark or VexPro hex shaft (http://www.andymark.com/product-p/am-2291.htm?CartID=1)

- 2 BaneBots Wheel, 2-7/8" x 0.8", 1/2" Hex Mount (http://banebots.com/pc/WHB-HS4-298/T80P-295BA-HS4)

- 2 BaneBots Wheel, 3-7/8" x 0.8", 1/2" Hex Mount (http://banebots.com/pc/WHB-HS4-398/T80P-395BA-HS4)

- 10 (?) Clamping Shaft Collar - 1/2" Hex ID (http://www.vexrobotics.com/shaft-collars.html)

We have some geared motors (http://www.andymark.com/product-p/am-0915.htm) coming as a part of FIRSTChoice. What should we do in terms of sprockets: 25 series (http://www.andymark.com/product-p/am-2182.htm) + (http://www.andymark.com/product-p/am-0749.htm)?

Putting the shaft through the aluminum tubing - how is this done? Is there enough space for hex bearings?

[androb4]

Originally Posted by jlian

So I should get

- Aluminum tubing from local aluminum shop (http://www.alustock.ca/Square-Tube-SC-1x0.125-AMR1465)

- AndyMark or VexPro hex shaft (http://www.andymark.com/product-p/am-2291.htm?CartID=1)

- 2 BaneBots Wheel, 2-7/8" x 0.8", 1/2" Hex Mount (http://banebots.com/pc/WHB-HS4-298/T80P-295BA-HS4)

- 2 BaneBots Wheel, 3-7/8" x 0.8", 1/2" Hex Mount (http://banebots.com/pc/WHB-HS4-398/T80P-395BA-HS4)

- 10 (?) Clamping Shaft Collar - 1/2" Hex ID (http://www.vexrobotics.com/shaft-collars.html)

We have some geared motors (http://www.andymark.com/product-p/am-0915.htm) coming as a part of FIRSTChoice. What should we do in terms of sprockets: 25 series (http://www.andymark.com/product-p/am-2182.htm) + (http://www.andymark.com/product-p/am-0749.htm)?

Putting the shaft through the aluminum tubing - how is this done? Is there enough space for hex bearings?

I would get the shaft and wheels from VEX just to minimize the vendors for convenience.

[geomapguy]

Originally Posted by androb4

I would get the shaft and wheels from VEX just to minimize the vendors for convenience.

Well he might be using the BaneBots voucher

But yes, get the hex shaft from Vex..(cheaper)

[sanddrag]

I'm a bit concerned about bending a 1/2" 7075 hex shaft over a 26" span. We've done it before. So, I'm considering using a 3/4" hex shaft. Am I out of my mind here?

Also, I'd like to build a pickup very similar to Ri3D 1.0, but I noticed, that robot didn't have bumpers. That's why it works so well. Bumpers make a BIG difference. I did some "Crayola CAD" on the geometry of it, and I can't find a way to avoid A LOT of compression on the ball during the point at which it goes over the bumpers, while still maintaining good contact and forward reach when the ball is on the ground. Any ideas there? Maybe we'll be okay with a 13" gap in the bumpers, which should help some.

[MichaelBick]

Originally Posted by sanddrag

I'm a bit concerned about bending a 1/2" 7075 hex shaft over a 26" span. We've done it before. So, I'm considering using a 3/4" hex shaft. Am I out of my mind here?

Also, I'd like to build a pickup very similar to Ri3D 1.0, but I noticed, that robot didn't have bumpers. That's why it works so well. Bumpers make a BIG difference. I did some "Crayola CAD" on the geometry of it, and I can't find a way to avoid A LOT of compression on the ball during the point at which it goes over the bumpers, while still maintaining good contact and forward reach when the ball is on the ground. Any ideas there? Maybe we'll be okay with a 13" gap in the bumpers, which should help some.

Interesting question. Just for sake of not popping balls we have been considering rollers instead of wheels. This would allow you to only exert forces on the end of the shaft too.

[Dan Richardson]

Originally Posted by sanddrag

I'm a bit concerned about bending a 1/2" 7075 hex shaft over a 26" span. We've done it before. So, I'm considering using a 3/4" hex shaft. Am I out of my mind here?

Also, I'd like to build a pickup very similar to Ri3D 1.0, but I noticed, that robot didn't have bumpers. That's why it works so well. Bumpers make a BIG difference. I did some "Crayola CAD" on the geometry of it, and I can't find a way to avoid A LOT of compression on the ball during the point at which it goes over the bumpers, while still maintaining good contact and forward reach when the ball is on the ground. Any ideas there? Maybe we'll be okay with a 13" gap in the bumpers, which should help some.

We found the shaft flexed quite a bit. We were concerned about yielding on a impact or fatigue over time. We created a center strut support in our design. It was just another piece of channel that we sectioned to slide into place.

This provide seemingly sufficient support and significantly reduced our concerns. This could have just as easily been 2 off center supports to further alleviate concerns.

[jlian]

Originally Posted by jlian

We have some geared motors (http://www.andymark.com/product-p/am-0915.htm) coming as a part of FIRSTChoice. What should we do in terms of sprockets: 25 series (http://www.andymark.com/product-p/am-2182.htm) + (http://www.andymark.com/product-p/am-0749.htm)?

Putting the shaft through the aluminum tubing - how is this done? Is there enough space for hex bearings?

Can someone help me on these?

[jblay]

Originally Posted by wilsonmw04

Check out Banebot wheels. They are cheap and made to take hex shafts. or AM star tube.


http://www.andymark.com/product-p/am...m?1=1&CartID=0

http://banebots.com/c/WHB-WM-HS4

I would not recommend using the churro tube for sure, it's not designed for such stresses.

Originally Posted by sanddrag

I'm a bit concerned about bending a 1/2" 7075 hex shaft over a 26" span. We've done it before. So, I'm considering using a 3/4" hex shaft. Am I out of my mind here?

I feel like anything that would bend a steel hex shaft, even 1/2 inch means you are over compressing the ball and I'd be concerned about popping it. We bent what I think was brass today when we over compressed on one of our prototypes.

Also gonna throw out there that the banebots wheels are insanely good at gripping this ball. In my, walk around the shop and touch stuff to the ball, they were by far the best. Didn't have any VEXpro wheels around though, I've heard good things about them as well.