The Tree Shark -A Tree Pruning Device-

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The Tree Shark-A Tree Pruning Device-

• Designed By
• Brian Carlin
• Bryan Fors
• Anne Petrofsky

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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

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Reasons For 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

Branches obstructing roadway
After Pruning
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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

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Pruning Methods

• Damage Prevention
• Trimming at appropriate section of limb
• Proper Tools
• Dont damage bark
• Dont cut live portions of tree
• Promotes healing of new cut

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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

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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

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Conceptual Design Process
Straight Reciprocating
Lopper

• Dependant upon operators 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 cant 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

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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

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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

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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
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Proof of Concept
Circular Skill Saw

• Aluminum Pole
• 8 Length
• Power
• Wall Outlet - 120V
• Head Fixture
• Circular Saw
• Jigsaw
• Sawzall

• 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

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Tree Shark-Final Design
Circular Saw Head
Battery and Trigger
Secondary Handle
Telescopic Pole
Final Prototype Cost 500 Estimated
Mass-Produced Cost 125
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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
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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
67 Maximum pole length 12
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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)

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Ansys Calculations-Final Design
Total Stress 4,621 psi Yield Strength for
Aluminum 40,000 psi
Highest Stress Location
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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
Factor of Safety for Head Fixture 245
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
10-32 Round Head Fasteners
6-32 Round Head Fasteners
Steel T-Brackets
Factor of Safety for Handle Fixture 550
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VIDEO
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Future Optimization

• Lower Overall Weight Improve Maneuverability
• Increase Blade Diameter Improve Cutting
  Larger Branch Diameters
• Develop Permanent Molded Plastic Fixtures

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Questions??
2
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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
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Proof of Concept-VIDEO
Jigsaw
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Vibration Calculations
Pole Natural Frequency 20.89 Hz
Natural Frequency Equation fn (1/2pi)
v(k/m) f n natural frequency k spring
constant m mass
Motor Natural Frequency 60 Hz