pic: Winch-atize me, Cap'n!!

[NShep98]

Originally Posted by Chris Hapstack

loading photo ...

This is what our climber would look like if it worked consistently.

[trumpthero786]

Looks very well built! I love custom gearboxes like this. I'd also love to see the rachet and pawl. It sounds better than using a socket wrench Thanks for sharing this!

[Chris Hapstack]

Originally Posted by trumpthero786

Looks very well built! I love custom gearboxes like this. I'd also love to see the rachet and pawl. It sounds better than using a socket wrench Thanks for sharing this!

No problem! Here's the ratchet attached to 60-tooth gear. Big thanks to our sponsor Lakeshore Cutting Solutions in Zeeland who waterjet cut this for us.

http://i.imgur.com/BVaQa2e.jpg

[Chris Hapstack]

A couple more pictures:

Gearbox plates shown with two copies of the ratchet and pawl (why not have an extra just in case?): http://i.imgur.com/JpiDqYV.jpg

Gearbox structure assembled: http://i.imgur.com/oZToaec.jpg

[trumpthero786]

Originally Posted by Chris Hapstack

No problem! Here's the ratchet attached to 60-tooth gear. Big thanks to our sponsor Lakeshore Cutting Solutions in Zeeland who waterjet cut this for us.

http://i.imgur.com/BVaQa2e.jpg

Ah cool. I see it now in the original picture too. Looks awesome.

[pilleya]

Looks great, there is some serious lifting torque produced in that gearbox. Planning on lifting the other alliance members? According to the JVN calc it could lift 3 150lb robots in under 4 seconds

[Chris Hapstack]

Originally Posted by pilleya

Looks great, there is some serious lifting torque produced in that gearbox. Planning on lifting the other alliance members? According to the JVN calc it could lift 3 150lb robots in under 4 seconds

Thanks!

The stall load is theoretically right around 1000 pounds, but I think we'll stick to just lifting ourselves so we can keep the current draw at a manageable level haha. Right now we're looking at about 15 amps per motor under the expected load.

Here are the exact numbers if anyone is interested (eternal thanks to JVN):
http://i.imgur.com/kmWySyK.png

(And always obey the curve: http://motors.vex.com/bb-775)

[Fusion_Clint]

Nice, I love the design.

I highly suggest steel gears for the final stage, we were using the vexpro gears and broke several teeth during the Bayou Regional which is the reason we were not able to hang during the quarter finals.

Our stall torque was just slightly higher than your calculated,

[pilleya]

Originally Posted by Fusion_Clint

Nice, I love the design.

I highly suggest steel gears for the final stage

Unfortunately Andymark does not sell 18 tooth steel gears with a 1/2 inch hex bore.

While the final stage gears might not be able to take the stall torque generated by the 775's, the ratchet means that the motors should never need to be be stalled.

[Chris is me]

Originally Posted by pilleya

Unfortunately Andymark does not sell 18 tooth steel gears with a 1/2 inch hex bore.

While the final stage gears might not be able to take the stall torque generated by the 775's, the ratchet means that the motors should never need to be be stalled.

It's not even just stall torque - it's torque under load, particularly with the long cantilever on the shaft. Pulling your robot up with one of these should work for awhile, but before you know it, you could snap teeth on that pinion gear, fall from the tower, and lose your regional. Happened to me in 2013. Still bitter.

If you could somehow double the face width of that gear (second pinion / output gear) that would help I think. Maybe you'll be okay with this, I dunno.

[Fusion_Clint]

Originally Posted by pilleya

Unfortunately Andymark does not sell 18 tooth steel gears with a 1/2 inch hex bore.

While the final stage gears might not be able to take the stall torque generated by the 775's, the ratchet means that the motors should never need to be be stalled.

They do sell this 19 tooth one, which I bet would also work.

http://www.andymark.com/Gear-p/am-0176.htm

We wound up using one of these paired with a this mecastercarr gear that we machined the bore ourselves. http://www.mcmaster.com/#6325k73/=11up3mm

Just trying to help.

It wasn't our first choice, but is nice not breaking teeth every other match.

[Chris Hapstack]

Originally Posted by Fusion_Clint

Just trying to help.

It wasn't our first choice, but is nice not breaking teeth every other match.

Yeah absolutely, thanks a bunch!

[BumblingBuilder]

How much does the entire apparatus weigh? Our team has been experimenting with mechanisms under intense weight constraints, and I'm interested in how much such a wickedly powerful custom gearbox setup such as this weighs.

[Chris Hapstack]

Originally Posted by Fusion_Clint

Nice, I love the design.

I highly suggest steel gears for the final stage, we were using the vexpro gears and broke several teeth during the Bayou Regional which is the reason we were not able to hang during the quarter finals.

Originally Posted by Chris is me

Pulling your robot up with one of these should work for awhile, but before you know it, you could snap teeth on that pinion gear, fall from the tower, and lose your regional.

Thanks for bringing up the gear tooth failure issue! If we end up breaking teeth, the plan is to buy some steel replacements from Boston Gear and hex-broach them ourselves. Also, I’m sure the winch could tear itself apart in many different places if it actually tried to lift 1000 pounds.

Originally Posted by BumblingBuilder

How much does the entire apparatus weigh?

The entire winch system here comes to 4.7 pounds (was hoping to get closer to 4, but oh well). That doesn’t include speed controllers, though.

[carpedav000]

Originally Posted by trumpthero786

Looks very well built! I love custom gearboxes like this. I'd also love to see the rachet and pawl. It sounds better than using a socket wrench Thanks for sharing this!

What's wrong with ratcheting wrenches?