pic: Flaming Monkeys 2016 Power Take-Off Gearbox


Hello CD,

Our team is planning to use a custom designed and machined Power Take-Off gearbox this year. It is based off of VEXpro’s ball shifting gearboxes, but all plates and shafts will be custom made. Current specs are:

[]14.4 ft/s adjusted speed with 6 inch wheels according to JVN design calc
]6.8:1 reduction on PTO shaft, with probably another 3:1 from pulleys. According to JVN design calc, this gives 1400(!) lbs force at stall with a 2 inch diameter pulley.
[*]According to SolidWorks, ~4 lbs plus motors.

Slip rings/ spacers for gears are currently not shown in the model.

Please feel free to ask questions or make suggestions. Any input is appreciated!

GrabCAD link

What made you go with a custom ballshifter shaft over the COTS options? What made you go with a belt pulley output over a shaft or sprocket output?

whoops, misread

I imagine the ability to customize the length of the shaft to allow other gears to be placed on it. We are using a similar layout, and had to jump through some major hoops and do some weird things to make the COTS shifter shaft work. If we had the machining resources to build our own ball shifter shaft this season, we would have jumped on it in a heartbeat.

Custom can often be much simpler than COTS.

Go Monkeys Go!
See you a week from Sunday?

Team members will be there. Robot will be there too if it’s fully functional.

The main driving factor was actually price. These gearboxes are about half the cost of the rocketboxes or WCP DS with PTO. We also wanted the ability to fine tune the reduction and keep it compact while retaining 3 CIMS. The design we came up with required the ball shifting shaft to be driven directly by the motors, so we needed a custom shaft to keep the size small.

We are not set on belt output (lift system is most likely waiting until after bag), it was just in there for spacing.

Let me know if you have other questions or if that explanation was unclear.