The Tree Shark -A Tree Pruning Device-

1. The Tree Shark-A Tree Pruning Device- Designed By: Brian Carlin Bryan Fors Anne Petrofsky

2. Problem Statement Design: • New light-weight tree pruning device • Operated by one person • Use in remote areas by people such as Forest Service employees, farmers and homeowners living in rural areas Specifications: • Reach up to 15 feet in height • Cut branches up to 2 inches in diameter in reasonable time • Safe to operate • Easily stored

3. Reasons For Pruning Branches obstructing roadway After Pruning • For exposure to light and air • Removal of dead or diseased wood • Maintains tree strength • Aesthetically pleasing • Assist with space for additional planting • Safety • Trimming branches near power lines/electrical equipment, roadways or sidewalks

4. Pruning Methods Crown Thinning: Process of removing branches from the crown of the tree • Aesthetically pleasing • Maintains tree structure • Allows for exposure to light and air • For both the tree and surrounding plants • Crown Raising: Process of removing branches from the bottom of the tree • Creates clearance underneath tree • Assists with obstruction of sidewalks or roadways

5. Pruning Methods Damage Prevention • Trimming at appropriate section of limb • Proper Tools • Don’t damage bark • Don’t cut live portions of tree • Promotes healing of new cut

6. Safety-OSHA Requirements T.C.I.A. – Tree Care Industry Association O.S.H.A. – Occupational Safety and Health Administration Regulatory bodies who work together to provide comprehensive guidelines for the tree care industry. They stress the importance of the safety of the tree professional and the protection of their company. • Circular Saw blade regulations: • Blades over two inches in diameter shall have a constant pressure switch and shut off can be accomplished by a single motion of the same finger(s) that turned it on • Protective guards shall cover both the top and bottom of the radial blade • Bottom guard shall make contact with the material that is being cut at all times. • General guidelines : • Wear Eye Protection • Wear Protective Footwear • Operating 10 feet from power lines over 700 volts if not properly trained through OSHA

7. Current Market Manual Pulley System Pros: Lightweight Cheap Cons: Most are a fixed length Not meant for branches larger than 1” diameter Requires 3-cut sequence to trim • Pole Saws/Chainsaws • Pros: • Able to cut larger branches • Availability • Cons: • Require gas/oil mixture to run or wall outlet • Heavyweight • High risk of blade “Kick-back” • Less accurate cut • Hydraulic System • Pros: • Powerful • Cons: • Expensive ($1000+) • Weight issues • Mobility

8. Conceptual Design Process Straight Reciprocating Lopper • Dependant upon operator’s force • Difficult to maneuver • Blade sharpness determines cleanliness of cut • Requires multiple “pulling” actions to sever limb fully Chainsaw/Band saw • Angle of cutting needs to be precise • Perpendicular angle difficult to obtain • High risk of “kick-back” force • Likely in hard wood • Any imperfections in wood • High risk of blade “kick-back” during rotation – can’t hit tip of blade • Cuts less accurate due to blade schematic • Run by engine or wall outlet • Blade unprotected during use Blade Options Circular Saw • Diameter of blade indicative of limb cutting ability • Easily replaced blade • Blade teeth move in one direction • Angle of approach less imperative • Blade able to reach high RPM to cut cleanly in any direction

9. Conceptual Design Process Solid Pole • Less flexibility • More rigid • Length restriction due to bending • Cheap • Difficult storage • Fixed Length Pole Options Telescoping Pole • Extendable and retractable for easy storage • Can operate at several lengths • Locking collar can provide reinforcement • and rigidity • More expensive

10. Conceptual Design Process Gasoline Engine Outlet • Heavy/bulky • Pull start, could cause inconvenience • Gas and oil maintenance • Spark plug maintenance • Unhealthy emissions • Restricted by extension cord • Must have outlet readily available • Able to draw as much current necessary Power Source Battery Power • Rechargeable • Lightweight • Easy replacement • Increased range/mobility • Environmentally friendly – no emissions

11. Ansys Calculations-Proof of Concept • Predicted Parts • Aluminum Telescoping Pole • 12’ Length • Circular Skill Saw • 4700 RPM • ¾ Hp H = Tn / 63025 H = Horsepower (hp) T = Torque (lbf-in.) n = Shaft Speed (RPM) 10lb Load Creates 3.436” Deflection

12. Proof of Concept • Aluminum Pole • 8’ Length • Power • Wall Outlet - 120V • Head Fixture • Circular Saw • Jigsaw • Sawzall Circular Skill Saw • Jigsaw • Excessive vibrations • Unclean cut-bark tearing • Only cut 1” diameter branch • Sawzall • Too heavy to fixture Jigsaw Sawzall • Circular Saw • 4700 RPM • ¾ Hp • 12 lb • Clean cut • Cut 1”-3” diameter branches • Minimal kickback and vibrations

13. Tree Shark-Final Design Circular Saw Head Battery and Trigger Telescopic Pole Secondary Handle Final Prototype Cost: $500 Estimated Mass-Produced Cost: $125

14. Parts List Makita 6 ½ ” Skill Saw Trigger Placement Handle Battery Pack Specifications: Diameter: 6-1/2" Arbor: 5/8" No Load Speed: 3,700 RPM Max. Cutting Capacity: 2-1/4" Battery: 3 Ah Net Weight (w/battery): 7.1 lbs Removed Guiding Bracket Motor and Circular Blade

15. Parts List Secondary Handle Secondary Handle Lower Handle Conceptual Drawing Actual Spring Locking Mechanism Aluminum Telescopic Pole Double Insulated Coiled Wiring Specifications: OD (Section 1): 1.786” ID (Section 1): 1.767” OD (Section 2): 1.574” ID (Section 2): 1.486” Minimum pole length: 6’7” Maximum pole length: 12’

16. Ansys Calculations-Final Design H = Tn / 63025 H = Horsepower (hp) T = Torque (lbf-in.) n = Shaft Speed (RPM) Moment from Blade: 17.74 lbf-in Total Deflection: 1.374” = 4lb Load Applied (total saw weight) +

17. Ansys Calculations-Final Design Total Stress: 4,621 psi Yield Strength for Aluminum: 40,000 psi Highest Stress Location

18. Fixture Calculations-Final Design Head Fixture T brackets fastened inside motor housing Handle Fixture #10-32 Round Head Fasteners Steel T-Brackets n = SpAt – Fi /CP n = load factor At = tensile-stress area of bolt Sp = proof strength Fi = preload C = fraction of external load P carried by bolt P = external tensile load N = number of bolts Factor of Safety for Head Fixture: 245 #6-32 Round Head Fasteners #10-32 Round Head Fasteners Steel T-Brackets Factor of Safety for Handle Fixture: 550

19. VIDEO

20. Future Optimization • Lower Overall Weight – Improve Maneuverability • Increase Blade Diameter – Improve Cutting Larger Branch Diameters • Develop Permanent Molded Plastic Fixtures

21. Questions?? 2”

22. Fixtures-Final Design Secondary Handle/BIOMECHANICS Secondary Handle: -32” from base -Mechanical advantage of .22 3rd Class Lever Both arms positioned with available room for flexion or extension

23. Proof of Concept-VIDEO Jigsaw

24. Vibration Calculations Pole Natural Frequency: 20.89 Hz Natural Frequency Equation: fn= (1/2*pi) √(k/m) f n = natural frequency k = spring constant m = mass Motor Natural Frequency: 60 Hz