Crab Drive

[Joe_Widen]

Well we built basically our whole robot out of lexan(polycarbonate), so we have a bunch of scraps. Now, since its basically just so everyone can get the general idea, not function, I'm making out of 1/4" lexan. The hole module is pretty much 3 3*6 pieces of lexan, 2 3*3 pieces, 2 1*3 pieces, a few standoff's, and some angle iron. I have a parts list for one that is strong, made of aluminum, inclueds driveshafts, gear, keys, bearings, and costs less than two andymark 2-speed shifters.

Parts (11.76:1 gear ratio)


Modules
8 Steel Plain Bore 14-1/2 Deg Spur Gear 20 Pitch, 48 Teeth, 2.4" Pitch Diameter, 3/8" Bore
4 Steel Plain Bore 14-1/2 Deg Spur Gear 20 Pitch, 15 Teeth, 0.75" Pitch Dia, 3/8" Bore
12 Steel Ball Bearing Plain Open for 1/2" Shaft Dia, 1-1/2" Od, 7/16" W
8 Steel Ball Bearing Plain Open for 3/8" Shaft Dia, 1-1/8" Od, 3/8" W
1 Fully Keyed Steel Drive Shaft 3/8" Shaft Od, 3/32" Keyway Width, 12" Length
1 Fully Keyed Steel Drive Shaft 1/2" Shaft Od, 1/8" Keyway Width, 24" Length
1 Plain Steel Oversized Key Stock 3/32" X 3/32", 12" Length
1 Plain Steel Oversized Key Stock 1/8" X 1/8", 12" Length
1 Alloy 7075 Aluminum Rectangular Bar 1/4" Thick, 4" Wide, 6' Length
1 Alloy 6061 Aluminum Rectangular Bar 3/16" Thick X 3" Width X 6' Length
1 Alloy 6061 Aluminum Rectangular Bar 1/4" Thick, 5" Width, 3' Length
1 Alloy 6063 Aluminum Round Tube .750" Od, .620" Id, 8' Length
20 Aluminum Female Threaded Hex Standoff 3/8" Hex, 1" Length, 10-32 Screw Size
10 Aluminum Female Threaded Hex Standoff 1/2" Hex, 3" Length, 1/4"-20 Screw Size
(angle iron was at our school)

Total Cost: $654.93