1640 Pivot Drive Value Engineering 22 November, 2010

1640 Pivot Drive – 2010 version Our first year with Pivot Drive Combines agility with force Provides competitive advantage Enables game-specific drive modes Comes at a price: Mass (40 lb) 8 Motors & motor controllers $s for materials Requires highly-skilled drivers Programming is formidable High-level machining & assembly capabilities

Value Engineering Value Engineering seeks to widen the gap between a device’s value (to the user/customer) and its cost by: Increasing the value (performance); Reducing the cost (traditionally $s, but mass, motors, driver skill,… apply as well); or both

Observed Performance Deficiencies Pivot tube / Pivot top joint failed on two occasions – unrepairable Set screws unreliable Transfer axle drift Wheel drift Pivot repairs (x-wheel tread changes) take too much time Side plate bolts loosened in use Pivot Angle not very accurate

Cost Mass Pivot mass 40 lb $s – 2010 Pivot materials cost $1,250 Machining – get best value for machine time Programming – 2 nd run should be easier Driver Skills – we need 2 new drivers trained (May)

Pivot 7e Pivot tube / Pivot top joint strengthened Transfer axle redesigned to eliminate need for set- screws PVC spacer replaces Collar on sprocket side of wheel Clamp collar replaces simple set-screw collar non- sprocket side Sealed 1” Ball Bearing Races Replace button heads with flat heads Pivot side tabs allow #10 screws on brace Pins for side & brace alignment More relief for mass reduction Timing belt replacing steering chain

Straw man – Modular Pivot Target – Replace a Pivot in 5 minutes Modular unit includes Pivot, Motors, Encoder(s), chains, belts,… Unit inserts into bottom of chassis (7) ¼”-20 bolts + electrical connections L & R spares will be needed (2) mounting orientations possible

Straw man – Modular Pivot

Straw man – Mounting Options

Actions – Pivot 7e Use 1” OD x ¼” wall 6061 tube for Pivot tube. Eliminate bottom lip & inset. Eliminate alignment hole. Rely on tight (thermal) fit. Drill (6) weight reduction holes in the 22T sprocket

Actions – Straw man Module Replace 2” x 1” U-channel spacers with 2” standoffs Stick with (5) bottom plate bolts – eliminate side wall fasteners to chassis frame Add stiffening rib to top plate along Pivot – CIM axis Top of stiffening rib to double as encoder mount base Use timing belt for CIM-Pivot drive (in lieu of chain) Set CIM in a pivoting mount to allow belt tensioning Use ball bearing race for top of BaneBots P60 shaft Tie top plate to top frame? Steering belt needs a tensioning means

Actions - Organization We need the mill moved and set-up Will we have a CNC lathe? If so, need this set up too Need tools. Ben Kellom to develop list We will need to design and build jigs for fabbing these parts, aide accurate assembly, welding the chassis and the drilling bolt holes in the chassis

Notes (captured thoughts) The Pivot Module is amenable to inclusion of shock-absorbing mounts between the module & chassis frame 7075 Al should be considered for specific high-stress, non-welded parts Consider thermal fit for miter gears & 9T sprocket on transfer shaft

Participants Douglas Molly Shasha Andrew Ben Kellom Gary Deaver David Moyer Siri Maley Clem McKown  Faith McKown  Rita Wall  John Weissman