1640 Pivot Drive

Value Engineering22 November, 2010

1640 Pivot Drive – 2010 version

Our first year with Pivot DriveCombines agility with forceProvides competitive advantageEnables game-specific drive modesComes 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 – unrepairableSet screws unreliable Transfer axle drift Wheel drift

Pivot repairs (x-wheel tread changes) take too much timeSide plate bolts loosened in usePivot Angle not very accurate

Cost

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

Pivot 7ePivot tube / Pivot top joint strengthenedTransfer axle redesigned to eliminate need for set-screwsPVC spacer replaces Collar on sprocket side of wheelClamp collar replaces simple set-screw collar non-sprocket sideSealed 1” Ball Bearing Races Replace button heads with flat headsPivot side tabs allow #10 screws on bracePins for side & brace alignmentMore relief for mass reductionTiming belt replacing steering chain

Straw man – Modular Pivot

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

Straw man – Modular Pivot

Straw man – Modular Pivot

Straw man – Modular Pivot

Straw man – Modular Pivot

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” standoffsStick with (5) bottom plate bolts – eliminate side wall fasteners to chassis frameAdd 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 tensioningUse ball bearing race for top of BaneBots P60 shaftTie top plate to top frame?Steering belt needs a tensioning means

Actions - OrganizationWe need the mill moved and set-upWill we have a CNC lathe? If so, need this set up tooNeed tools. Ben Kellom to develop listWe 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 frame7075 Al should be considered for specific high-stress, non-welded partsConsider thermal fit for miter gears & 9T sprocket on transfer shaft

Participants

DouglasMollyShashaAndrew

Ben KellomGary DeaverDavid MoyerSiri MaleyClem McKown

Faith McKownRita WallJohn Weissman