Guts are from the AM Sonic Shifter, belts are 5mm Pitch HTD(probably overkill looking back on it)and 2:1 Bevel output.
It’d be cool if someone took this to an actual robot.
Is the dog gear on the same shaft as the bevel gear? Have you done any investigation into how the thrust loads on that shaft will impact the dog?
The dog gear is on the same shaft as the 42T Belt pulley, not the bevel gear.
With how thin those belts are I wouldn’t say that it’s overkill.
What would be the benefit of this over a traditional shifting gearbox? The only thing I could think would be it’s slightly thinner, which leaves more room for stuff between the gearboxes. But that at the expense of an additional ~5% efficiency loss and a lot of added complexity doesn’t seem worth it to me. Is there something I’m missing?
It’s much more nifty.
It’s likely just for the packaging. OP is an alumnus of 192 GRT, who has a history of repackaging drive gearboxesfor space, at potentially some efficiency cost. It’s a choice, whether it’s worth it or not depends on what’s important for the rest of the robot/strategy.
Some other advantages this gearbox could provide is the ability to swap CIM motors easily, without disassembling the gearbox. If mounted in a traditional WCD setup, there’s easy access to the screws on top and a relatively small hole in the belly pan can make it possible to drop and swap the motors.
Very interesting. First thing I though of was “Wow, this looks like 192’s old gearboxes” and lo and behold, an alumnus of 192!
I really like this packaging. Giving up vertical space for space over the rails and between the rails is a really good tradeoff IMO, at the expense of cost and needing to align bevels. If you’re using 5mm HTD belts, WCP now sells a 12t pulley for CIMs as a COTS option.
Yea, Jason designed this while working at AndyMark last summer with our usual design philosophy of “using as many on the shelf parts as possible” We actually have had a 12T 5mm HTD CIM pulley in stock for a while for the DART, it just never made it up as it’s own product. I’ll see what I can do about fixing that next week.
You forgot the actual bevel gear one lol… 
Spot on. The ease of just dropping a CIM out of the bottom of the gearbox was definitely a huge plus.
The gearbox is largely done using only AndyMark parts, I’d be interested to see someone change some key features (First stage belt pitch/helical bevel gears) and get this thing more efficient.
Are you my spirit animal?
Doesn’t the use of belts on the first stage kinda defeat the purpose of ease of removal since belts can be a pain to get on and off and so can the accopanying pulleys?
Given that the pulleys seem to have set screws, I don’t think it would be difficult to get them off at all.
That really depends on how much tension is in the belts so yea good point if the belts are relatively loose but if the belts are really tight then getting it on and off may be very hard.
