Table of Contents

Linear Actuator Base Arm/Elbow Joint Future Plan

Previous Issues:

• Rack and gear meshing slop

• Uniform linear movement through bearings

• Drive motor needs replacement

Improvement Ideas:

• Mount second gear to face of primary gear

• Replace linear roller bearings with sleeve bushings

• Replace motor with higher torque version

Linear Actuator

Gears/ BushingsFasten new gear to primary gear to increase contact area of gear to linear rack

Chose sleeve bushing to increase surface contact on rack to increase stability

Will reduce twisting and bending slopEliminate linear ball bearing for smoother motion

MotorCurrent motor is inopperable

256:1 Motor ordered to replace the 64:1 motor previously in place.

Higher Torque, but lower speed

Base Setup

POT

Drive Gear

Current Base Setup

~1/8” slop from lazy susan

Drive Gear

New Base Setup

Direct Drive Motor

Base Plate Connection

DriveBearing

Moving part of

motor

Arm/Elbow Problems

1/8in armsArm twists too muchNot rigid enough assembly

Elbow helical gearsCreates lateral loads on armLow gear ratio results in small torque

increasesExposed gearing picks up debris

Quick Fix Ideas Channel Arm Idea

Lighter, strong, resists torsion, but hard to make

Square Tube IdeaHeavier, strong, and

easier to make

New Arm 1st iteration

Progress so far

Test Assembly: Chipping Rock

Goal: Replace the linear actuator with a more powerful assembly to break rock.

Future Milestones

1st Iteration redesign – Nov. 28thth

Interim Report Fall Semester – Dec. 9th

Final Design Decision – Dec. 2008

Senior Design Expo – May 2008