Automatic Hole-Cutter
for a Golf Course Green
by
KYLE C. HANSELL
Submitted to the
MECHANICAL ENGINEERING TECHNOLOGY DEPARTMENT
In Partial Fulfillment of the
Requirements for the
Degree of
Bachelor of Science
In
MECHANICAL ENGINEERING TECHNOLOGY
'~
''
at the
OMI College of Applied Science
University of Cincinnati
May2005
© ...... Kyle C. Hansell
The author hereby grants to the Mechanical Engineering Technology Department
permission to reproduce and distribute copies of the thesis document in whole or in part.
Signature of Author
Certified by
~
Accepted by
',(_ &
Janak Dave, PhD,
Thesis Advisor
¢ ~ Dr. Muthar Al-Ubaidi, Department Head
Mechanical Engineering Technology
ABSTRACT
Cutting golf holes at public and private golf courses has been done for
many years by manual hole-cutters. These manual hole-cutters have created
many problems over the years. Technology is changing and it’s time for an
Automatic Hole-Cutter for a Golf Course Green. This cutter will benefit both
employer and employee along with being beneficial to the golf course itself.
The Automatic Hole-Cutter for a Golf Course Green will change the way
all golf holes are created. The cup cutter is easily operable and will allow for any
age of employee to cut the cup.
The report includes a review of the design, fabrication, and assembly of
the hole-cutting portion of the Automatic Hole-Cutter. Also included in the report
are the project budget, manufacturer’s specifications, mechanical drawings,
instruction manual, project schedule, project data, and the project calculations.
2
TABLE OF CONTENTS
ABSTRACT……………………………………………………………………..……...ii
TABLE OF CONTENTS………………………………………………………..……..iii
LIST OF TABLES & FIGURES………………………………………………..……..iv
INTRODUCTION TO THE AUTOMATIC HOLE-CUTTER.………………..….…..1
BACKGROUND OF AUTOMATIC HOLE-CUTTER……………..………..1
PROBLEM WITH EXISTING HOLE-CUTTERS........................................1
SOLUTION TO HOLE-CUTTING PROBLEMS…………………..………...1
AUTOMATIC HOLE-CUTTER RESEARCH..............................................2
AUTOMATIC HOLE-CUTTER RESEARCH FROM SURVEYS………..…………4
AUTOMATIC HOLE-CUTTER OBJECTIVES………………..……………..………6
AUTOMATIC HOLE-CUTTER DESIGN SOLUTION...…………………..………...8
RESEARCH AND DESIGN ALTERNATIVES FOR HOLE-CUTTER.......8
FINAL DESIGN OF AUTOMATIC HOLE-CUTTER………………….…....9
HOW THE HOLE-CUTTING DESIGN WORKS…………………….……..14
POWERING AND WIRING THE CUTTER………………………..……….15
AUTOMATIC HOLE-CUTTER FABRICATION…………………………..………..17
TESTING THE AUTOMATIC HOLE-CUTTER……………….....……….………..18
FUTURE IMPROVEMENTS TO AUTOMATIC HOLE-CUTTER.……..…………19
THE CONCLUSION OF THE AUTOMATIC HOLE-CUTTER….……..………….21
BIBLIOGRAPHY………………………………….……………………………………22
APPENDICES
APPENDIX – A (Miscellaneous Figures)…………………..…….………23
APPENDIX – B (Project Data)…………………………..…….………..29
APPENDIX – C (Calculations)…………………………..………….…..37
APPENDIX – D (Manufacturer’s Specifications)………………..….…….50
APPENDIX – E (Mechanical Drawings)………………..…….………….59
3
LIST OF TABLES & FIGURES
TABLE 1
Measurable Objectives…………………………….…..……6
TABLE 2
Weighted Decision Matrix…………………………………..10
TABLE 3
Testing Results……………………………………..………..18
FIG. 1
Impact Hammer Design.…………………………….………8
FIG. 2
Final Design………………………………………….……….9
FIG. 3
Directional Slot Forces………………………………………12
FIG. 4
Threaded Rod/Nut Forces………………………….……….12
FIG. 5
Final Assembly…………………………………….…………14
FIG. 6
Wiring Diagram……………………………………..………...15
FIG. 7
Example of manual hole-cutter with scalloped blade….…24
FIG. 8
Example of manual hole-cutter with straight blade….……25
FIG. 9
Tabulated results from surveys……………………………...30
FIG. 10
QFD Matrix…………………………………………….……….31
4
INTRODUCTION TO THE AUTOMATIC HOLE-CUTTER
BACKGROUND OF AUTOMATIC HOLE-CUTTER: All golf courses require
the hole location on the green to be changed quite frequently (4 – 7 times a week
depending on the type of golf course). The movement of the hole allows for the
green to stay in good shape due to the amount of play from the golfers. The
conditions for cutting the hole can vary immensely due to the seasons and
weather conditions. To create these different pin locations a hole-cutter is used.
PROBLEM WITH EXISTING HOLE-CUTTERS: For golf course maintenance
no automatic device exists for cutting the hole in the putting surface. Manual
hole-cutters are the only things available on the market. The amount of labor
from the manual hole-cutters (See FIG. 7 & FIG. 8 in Appendix – A) can be fairly
intense for many individuals. This intense labor is especially difficult for retired
senior citizens which make up a fair amount of maintenance workers at the golf
course.
The soil density and weather conditions definitely play a major role in the
difficulty of the task at hand. From the hard work of the manual hole-cutter, other
tribulations begin to amount as well. Time, accuracy of the cut, and overall
appearance are some of the by-products that can result from the intense labor.
SOLUTION TO HOLE-CUTTING PROBLEMS: The solution is the Automatic
Hole-Cutter for a Golf Course Green. This automatic cup cutter will be almost
5
fully automatic except for transportation from the golf cart to the green which will
be done by hand.
Our group decided to break down our automatic hole-cutter into two
separate designs. One part of the design will deal with the lowering of the frame
using a system of linear actuators along with the chassis and controls. The
second part of the design, which is my part, will be the top half of the cup cutter
which is a system of a gear box, motor, threaded rod, and cutter blades to cut the
hole.
Everything on the top portion of this must be attached to a frame assembly
and connected to the main frame which my other group member will be
designing and building.
AUTOMATIC HOLE-CUTTER RESEARCH: The research for this product was
mainly centered around direct contact of individuals and/or organizations along
with patent research. My partner and I researched several companies and
interviewed a few local turfgrass employees to determine if any automatic holecutters exist. Lesco Golf Equipment, one of the leading golf course suppliers in
the Midwest, sells no type of automatic hole-cutter equipment or accessories[2].
The patent database also gave us no leads in regards to an automatic cup
cutter ever built. From this extensive research my partner and myself concluded
that no one had patented any type of device like the one we were building. This
was good news for any future marketability as well
6
After speaking with several golf course assistants and superintendents
along with my own research, it was concluded that there is no direct market for
the selling of automatic hole –cutters. Ed Minges, Superintendent of Circling
Hills Golf Course, said he was unaware of any such type of automatic hole-cutter
[3]. Mr. Minges has been in the golf course industry for over ten years.
Soil research was another aspect of the design process. Understanding
what the greens were made of was crucial in determining the forces needed to
cut the plug. Since our design was centered around greens at Circling Hills Golf
Course we needed to understand the properties of the greens there. Circling
Hills uses USGA sand based greens. The USGA greens consisted mostly of
sand so it was determined that the forces needed would be from that of cutting
into sand [4].
7
AUTOMATIC HOLE-CUTTER RESEARCH FROM SURVEYS
To achieve the best results possible for the surveys of our project, it was
decided to only send the surveys to individuals that would fully understand what
was being done with the automatic cup cutter. Therefore, surveys were sent or
given to golf course employees, superintendents, and other individuals in the turf
grass area.
Since we narrowed down our choice for customer survey recipients we
only sent it out to sixteen people. However, the sixteen surveys were extremely
beneficial. My design solution was directly centered around these results but
they were used to gain a good understand of what the customers would be
looking for.
From the surveys it was concluded that the following is what the
customers would like to see most:
1) Various speed capabilities
2) Minimum maintenance
3) Compact in size
4) Various Height Capabilities
5) Rechargeable power source
6) Ease of Transportation
The accurate cutting of the green was the most important from the surveys.
Since my portion of the project centers around the cutting of the plug, it was
important that I took that into consideration for the solution of my design.
8
For a complete list of the results from our surveys, please see FIG. 9 in
Appendix – B.
9
AUTOMATIC HOLE-CUTTER OBJECTIVES
From the surveys and our own research the needs for the project were
found. As mentioned with the survey section of this report it was determined that
speed and height capabilities, rechargeable power source, minimum
maintenance, compact in size, and transportation were among the most
important needs for a solution to our design.
With the surveys and research the following table was created to show our
measurable objectives:
Problem Element
Solution
Element
Labor Intensive
Lightweight, Frame
on wheels.
Time Consuming
Battery powered.
Accuracy of the cup
cut
Automated cutter.
Manual cut.
Automated.
Soil density
Heavy duty cutter
Weather Conditions
All weather device
Objective and its Measurement
Wheels and lightweight of frame allow for easy
movement of the cup cutter.
Cut time will be reduced by using battery powered
cutter.
But cutting the cup with an automated cutter a level and
consistent cup will be achieved.
Strenuous manual cut will be prevented by the
automated system.
By using the heavy duty cutter that is energized through
battery power, soil density should not be a problem.
Utilizing all-weather components and designing an
enclosed frame should allow for any weather
conditions.
TABLE 1 Measurable Objectives
As you can see from the figure the problem elements and solution elements were
organized to help achieve a sufficient means of a design solution.
10
The following are the final project objectives that would be used in the
proof of design concept: (See Appendix B for the actual Proof of Design)
1 The cutter must automatically cut a hole at a depth of 7” with a diameter of
4 ½” on a USGA sand based green.
2 The cutter must be able to automatically fully extract the hole plug from it’s
existing location
3 The hole plug must stay 90 percent intact with the sod portion being 100
percent intact until it reaches the final destination
4 The cutter must have a rechargeable power source that will allow for the
cutter to cut at least nine holes on the golf course
5 The cutter must be able to be completely controlled by the control deck
situated at the top of the automatic hole-cutter
11
AUTOMATIC HOLE-CUTTER DESIGN SOLUTION
RESEARCH AND DESIGN ALTERNATIVES FOR HOLE-CUTTER: The design
solution started out with much emphasis put on research of the product. By
getting all of the background information it allowed for a much better and more
customer oriented product. The research included everything with customer
surveys, key elements of design, and information to prove that no automatic
hole-cutter for a golf course green exists.
The customer surveys were collected after the research was finished. The
results were tabulated from the surveys and the quality function deployment was
then created (See FIG. 10 in Appendix – B). The QFD matrix is what gives you
the most important aspects of your design. With these important aspects, two
designs were chosen.
The first design alternative was an automatic hole – cutter that would cut
the plug through impact force with an impact hammer. The following figure is a
sketch of this design:
FIG. 1 Impact Hammer Design
12
In this design, the hammer drill would impact the fixture holding the cutter blades
and drive the blades down to cut the hole. A spring loaded mechanism would
help keep the impact hammer driving down.
This design alternative’s main advantage was it would be able to be used
on any green in any type of soil condition. However, it would create much more
wear on the parts and the operator would have to do much more work with it.
This work included raising the impact hammer and plug back up and steadying
the device as it hammered.
The next design was the threaded screw design and this design would
end up being the one used for the final design. The threaded screw design
would consist of the following:
FIG. 2. Final Design
13
The final design used a gear motor to turn an ACME threaded shaft, which would
generate the force to cut the plug.
The advantages of this design are it is able to cut and extract the plug all
with one source (the gear motor). It was also less expensive and would generate
less part wear. However, it was more limited to how much force it can cut into
the green.
Both designs were put into a weighted decision matrix and the screw
cutter design was the better design. The following is the weighted decision
matrix for the two designs:
TABLE 2 Weighted Decision Matrix
From viewing the table it can be determined that the screw cutter was definitely
the better design to use.
14
FINAL DESIGN OF AUTOMATIC HOLE-CUTTER: The final design began with
the determination of the amount of force it was going to take to cut into the USGA
sand based green (See Appendix – C for Calculations). An outside source was
used to help determining these numbers since these are unusual calculations for
a mechanical engineer to do. Professor Moussa Gargari of the University of
Cincinnati’s Construction Science Department assisted with these equations.
With Professor Gargari’s help, the bearing and friction force of cutting into a sand
based green were determined to be 66 lbs and 19 lbs respectively.
These soil calculations were basic calculations without any extreme soil
conditions. These extreme soil conductions could be from the compaction of the
soil from golfers stepping on it and/or dry soil at the end of the summer. With an
uncertainty of what these conditions could be an uncertainty load of three times
the original force was used in the calculations. Along with this uncertainty load
was a factor of safety of two. With these values in place, it was believed that
these factors would compensate for any extreme loading conditions.
The next part in the design process would be calculating the force put on
the shoulder bolt in the directional slot. The following figure shows the forces
and directional slot
15
FIG. 3 Directional Slot Forces
Since the angle of the slot was known along with the forces from cutting into the
sand, the normal force put on the shoulder bolts was obtained (See Appendix –
C for calculations). This normal force came out to be 30.23 lbf on one bolt.
With the normal force of the bolt in the directional slot, the nut/screw
forces were then obtained (See Appendix – C for calculations). The following is
a diagram of the forces acting on the threaded rod:
FIG. 4 Threaded Rod/Nut Forces
With the lead of the screw and the knowing the force on the pusher, the nut
torque was found. This torque was found to be 8.68 in lbf.
16
With this torque, the sizing of the motor was then found. Using a load
uncertainty of three, the motor torque was found to be 24.90in/lb. After the factor
of safety was put in, the motor was sized to at least 50 in lbs. By finding the axial
and radial cutter speeds (See Appendix – C for calculations) the motor speed
was then determined to be 170 rpm with a horsepower of .14. The motor was
selected accordingly (See Appendix – E for the actual motor being used). The
motor selected can handle 54 in lb of torque and has a hp of 1/6 and spins at 170
rpm.
The entire unit was also designed to handle a worst case scenario. The
worst case scenario for the automatic hole-cutter would be screwing down and
hitting a rock. The chances of this are extremely minimal but it was taken into
consideration anyway. This would stall the motor. With a stall torque of 302 in lb
from the motor, the max screw tangential force was then determined. The
threaded rod used for the design was an ACME 1” – 4 threaded rod with an
efficiency of 35 percent. With the stall torque, efficiency, and diameter of the
screw, the max screw tangential force was then obtained. With this max
tangential force and the specifications from the screw, the max axial force
heading back into the bearing was obtained. This force was found to be 2656
lbs.
The shearing of the bolts was analyzed and was negligible (See Appendix
– C for the calculations). However, the shearing was so minimal that shearing of
the shoulder bolts will never happen except for a defect in the product.
17
HOW THE HOLE-CUTTING DESIGN WORKS: The following is a final
representation of my part of the project:
FIG. 5 Final Assembly
From this representation it can be seen that a gearmotor powers a threaded rod
which turns itself on an ACME threaded nut. The ACME nut was welded onto
the pushing mechanism as seen above and then screw on to the threaded rod.
The pushing mechanism was locked into place from the shoulder bolts located
on the cylinder assembly. A second set of shoulder bolts are screwed into the
cutter assembly and are inserted in the directional slots on the cutting assembly.
18
These directional slots help cut the plug and allow for the gap created from the
cutting mechanism to be eliminated. If you view the inside assembly you will
notice a hinge and a large diameter hole on the inside of the assembly. This is
where a linear actuator will be mounted. The linear actuator (See Appendix – E
for linear solenoid) will provide the clamping force on the plug to keep it together.
The self closing hinge (See Appendix – E for self closing hinge) will take the
assembly back to its original state once the actuator is retracted.
POWERING AND WIRING THE CUTTER: The last part of the design is
powering and wiring of the automatic hole – cutter. The source had to be
rechargeable so a 12 volt car battery was determined to be the cheapest and
best route to go. The following is the wiring diagram for the motor:
FIG. 6 Wiring Diagram
19
In this diagram you will notice limit switches. These limit switches are located at
the edge of the pushing mechanism slot and will decide the seven inch distance
to cut the hole. The wiring diagram is the same for the actuator except without
the limit switches on it (See Appendix – A for wiring diagram of linear solenoid).
Fuses and relays were also used in the wiring of this project to ensure
safety of all the electronic parts. A 30 amp fuse was used and two 25 amp relays
were used in the wiring of the hole-cutter portion of this project.
20
AUTOMATIC HOLE-CUTTER FABRICATION
Overall, ordering the supplies for the Automatic Hole-Cutter encountered
few problems. The set date to order the parts for the Automatic Hole-Cutter was
March 20, 2005. That due date was met except for some minor parts and the
motor. The motor took a little bit longer due to purchase because of funding
issues. All parts were ordered from Grainger, Mcmaster-Carr, and Metals Depot
with the exception of some minor supplies purchased at local hardware stores.
April 25, 2005 was the set date to have the unit assembled. My partner
and myself failed to meet this date due to time delay issues with outside vendors.
However, we did make up some time and were able to complete our testing
deadline of May 10.
Most fabrication for the Automatic Hole-Cutter was done in-house except
for three components sent to Miami Products and Tri-State Tool and Grinding.
Miami Products had some time issues with machining of two of the parts which
set the Hole-Cutter’s assembly back a week. The welding of the project was
done in-house as well. The entire project was MIG (Metal Inert Gas) welded.
All final assembly and testing of the project were done at Circling Hills Golf
Course. The Circling Hills Maintenance Shop was used for assembly and the
actual testing was done on the golf course’s greens.
21
TESTING THE AUTOMATIC HOLE-CUTTER
Initial testing was done independently with the two separate assemblies.
However, not much could be done with the two separate entities. After the two
were combined final testing was then able to occur. Most of the final testing was
done on the Circling Hills Practice Green. Testing included the cutting of four
holes to see if the project worked. After that two more holes were cut and timed
to see how long it would take for the hole-cutter to cut as compared to the
previous times. Table 3 is a comparison of the manual time method with the
automatic time method.
AUTOMATIC HOLE-CUTTER FOR A GOLF COURSE GREEN
MANUAL HOLE-CUTTING TIME
1 3/4 HOURS FOR NINE HOLES
AUTOMATIC HOLE-CUTTING TIME
1 1/4 HOURS FOR NINE HOLES
TABLE 3 Testing Results
All testing and fabrication was finished on May 10, 2005 and our final
proof of design occurred on May 13, 2005 by Professor Janak Dave, project
advisor.
22
FUTURE IMPROVEMENTS TO AUTOMATIC HOLE-CUTTER
Operating and testing the Automatic Hole-Cutter on a golf course green
revealed some changes that could be made to improve the product. All of the
improvements are minor but would definitely help in selling the product to the
industry.
One recommendation that would be beneficial to the hole-cutter portion of
the design would be a greater angle in the directional slot to slow the cut down as
it penetrates the green. This angle would allow the cutter to spin more and cut
through the soil much better.
Other beneficial upgrades to the hole-cutter design would be a solid
cutting blade to allow for easier penetration into the soil. With two separate
blades the dirt plug tends to wedge itself up into the blades. This wedging action
makes it difficult to cut a deep hole in the green.
The chassis currently operates on one actuator. However, a second
actuator added to the back side of the chassis would allow for the back end to
elevate all the way up without struggling so much when a load is applied to it.
The only problem from adding a second actuator would be cost. The cost of
another actuator would be three hundred dollars.
Beneficial upgrades that could be added to the chassis would be selfpropelling it and installing a differential in one of the axles to allow for easier
turning. Having the chassis self-propelled would allow for the cutter to not have
to be brought up on the green. Instead it could be pushed up to the green from
the green’s lower surface.
23
Standing on the Automatic Hole-Cutter is fairly easy for a younger or
middle aged person but it can be awkward for a retired employee. Retired
Circling Hills Golf Course employees were able to stand on it but they found it to
be a little uncomfortable. A more accessible place to stand on the Automatic
Hole-Cutter would definitely be another improvement to the product.
24
THE CONCLUSION OF THE AUTOMATIC HOLE-CUTTER
The main goal of the entire project was to build and design a working
model that met all product specifications. The Automatic Hole-Cutter for a Golf
Course Green worked well, and with some minor changes, is definitely
marketable to the golf course industry. The Automatic Hole-Cutter could be
marketed to all golf courses with key interest to those courses that hire mostly
retired employees to handle their maintenance concerns.
The Automatic Hole-Cutter for a Golf Course Green not only worked but
exceeded many of the expectations set forth on it. With golf courses always
needing to change hole locations and with the hiring of more retired workers, the
Automatic Hole-Cutter could be very beneficial to the employer and the
employee.
25
BIBLIOGRAPHY
1.
Coursigns Inc. Golf Course Supplies.
http://www.coursigns.com/golf-course-cups.htm. 12/05/04
2.
Lesco. Products for Turf Care Professionals.
http://www.lesco.com/default.aspx?PageID=43&SubMenuItemID=98.
10/05/04
3.
Minges, Ed. Superintendent of Circling Hills Golf Course. Cincinnati;
09/25/04. Interview
4.
USGA. Green Section Recommendations.
http://www.usga.org/turf/course_construction/green_articles/putting_green
_guidelines.html. 01/10/05.
5.
Gargari, Moussa. Professor at University of Cincinnati Construction
Science Department. 01/28/05. Interview
6.
Mcmaster-Carr. Industrial Supply Company.
www.mcmaster.com. 03/14/05
7.
Grainger. Industrial Supply Company. www.grainger.com.
03/14/05
26
APPENDIX – A
MISCELLANEOUS FIGURES
WIRING DIAGRAMS
27
FIG. 7 Example of a manual hole-cutter on today’s market with scalloped
blade[1]
(THIS PRODUCT IS USED BY MANUALLY PUSHING IT INTO THE GREEN’S
SOIL WHICH CAN BE FAIRLY HARD TO DO)
28
FIG. 8 Example of manual hole-cutter with straight blade [1]
(THIS PRODUCT IS USED BY MANUALLY PUSHING IT INTO THE GREEN’S
SOIL WHICH CAN BE FAIRLY HARD TO DO)
29
WIRING DIAGRAM FOR MOTOR WITH LIMIT SWITCHES INCLUDED
30
WIRING DIAGRAM FOR LINEAR SOLENOID
31
FINAL ASSEMBLY OF PROJECT
32
APPENDIX – B
PROJECT DATA
33
Automatic Hole-Cutter for a Golf Course Green
Please indicate the level of importance you would attach to the following aspects of an Automatic Hole-Cutter
for a golf course green.
1 = Low Importance
1)
Product has various speed capabilities.
2)
5 = High Importance
1 (1)
2 (1)
3(2)
4 (6)
5 (6)
Product is easy to repair.
1
2
3 (5)
4 (4)
5 (7)
3)
Product Functions properly with minimum maintenance
1
2
3 (5)
4 (8)
5 (3)
4)
Product is appealing to the eye.
1 (15)
2
3 (1)
4
5
5)
Product can accurately cut green.
1
2
3
4
5 (16)
6)
Cutting tool rotates in both directions.
1
2 (3)
3 (4)
4
5 (6)
7)
As compact as possible.
1
2
3
4 (8)
5 (8)
8)
Product has various height capabilities.
1
2
3 (4)
4 (5)
5 (7)
9)
Product isn't noisy.
1
2 (14)
3 (1)
4 (1)
5
10) Rechargeable power source.
1
2
3
4 (8)
5 (8)
11) Product is easy to maintain.
1
2
3
4 (6)
5 (10)
12) Product is easy to operate.
1
2
3
4 (5)
5 (11)
13) Price of product.
1
2 (5)
3 (6)
4 (5)
5
14) Safety of product.
1
2
3 (1)
4 (1)
5 (14)
15) Ease of transportation.
1
2
3 (1)
4 (3)
5 (12)
Are there any other aspects you would like to see this product accomplish?
FIG. 9 Tabulated Results from Surveys
34
Strength
Durability
Maintenance
Ergonomics
Appealing
Noise
Space
New Features
Variable Speeds
Repairs
Can Rotate in Either Direction
Various Heights
Operation
Cost
Price
Safety
9
3
9
3
3
3
3
3
3
1
9
3
9
1
9
1
9
9
3
Relative Weight
Improvement Ratio
(Modified)
Sales Points
Improvement Ratio
Planned Design
Competitive Hole-Cutters
Customer Importance
Cost of Manufacture
Materials Used
Weight
Training
Dimensions
Type of Motor
Required Force
Adjustability (Time)
9 = Strong
3 = Moderate
1 = Weak
5
4
4
1
5
4
1.25
4
1.5
1.3
9.375
20.8
0.06
0.14
3
2
3
1
2
5
3
3
4
3
1.5
0.8
1.1
1.1
1.3
9.9
3.3
3.12
0.07
0.02
0.02
4
4
2
4
3
1
4
1
1
3
4
4
4
5
4
4
1
4
5
1.3333
1.5
1.3
1.3
1.5
1.3
24
5.2
10.4
30
5.2
0.16
0.04
0.07
0.20
0.04
5
5
44
3
2
3
5
1
2.5
1.5
1.5
7.5
18.75
147.55
0.05
0.13
1.00
Absolute Importance
0.0671 1.7486 1.0126 0.2013 0.0861 1.1437 1.4106 1.586 7.2559
Relative Importance
0.0092 0.241 0.1396 0.0277 0.0119 0.1576 0.1944 0.2186
FIG. 10 QFD Matrix
35
Gantt Chart
Fall and Winter Quarter
October
Task
Duration
Who
Product Research
Search Internet
Survey People
2 weeks
1 week
PC and KH
PC and KH
Other Research
Patent Research
2 weeks
PC and KH
Concept Design
Brainstorming
3 weeks
PC and KH
Frame
Tooling
Controls
Power Source / Motor
Lowering Frame
SolidWorks Drawing
3 weeks
5 weeks
1 week
6 weeks
6 weeks
3 weeks
PC
KH
PC
KH
PC
PC and KH
Manufacturing
Frame
Tooling
Controls
Power Source / Motor
Lowering Frame
Testing
1 week
4 weeks
2 weeks
2 weeks
3 weeks
PC
KH
PC
KH
PC
4
11
18
25
1
8
November
15
22
29
Design
Winter Presentations (March 2)
Tech Expo (May 19-20)
Items to be completed
Items completed
Items in progess
6
December
13
20
27
3
10
January
17
24
31
7
February
14
21
28
FOR FALL AND WINTER QUARTER
36
Gantt Chart
Spring Quarter
March
Task
Duration
Who
Product Research
Search Internet
Survey People
2 weeks
1 week
PC and KH
PC and KH
Other Research
Patent Research
2 weeks
PC and KH
Concept Design
Brainstorming
3 weeks
PC and KH
Frame
Tooling
Controls
Power Source / Motor
Lowering Frame
SolidWorks Drawing
3 weeks
5 weeks
1 week
6 weeks
6 weeks
3 weeks
PC
KH
PC
KH
PC
PC and KH
Manufacturing
Frame
Tooling
Controls
Power Source / Motor
Lowering Frame
Testing
1 week
4 weeks
2 weeks
2 weeks
3 weeks
PC
KH
PC
KH
PC
7
14
April
21
28
4
11
18
25
2
9
Design
Winter Presentations (March 2)
Tech Expo (May 19-20)
*
Items to be completed
Items completed
Items in progess
FOR SPRING QUARTER
37
May
16
38
SCREW CUTTER
Various Speeds
Accurate Cut
Rotates in both directions
Rechargeable
Easy to Operate
Safety Devices
Material Cost
Weight
0.12
0.24
0.08
0.2
0.18
0.12
0.06
Score
10
8
10
7
6
7
10
TOTAL =
Rating
1.2
1.92
0.8
1.4
1.08
0.84
0.6
7.84
HAMMER DRILL
Score
2
8
1
7
4
5
4
TOTAL =
Rating
0.24
1.92
0.08
1.4
0.72
0.6
0.24
5.2
39
BUDGET
Automatic Hole-Cutter For A Golf Course Green
MATERIALS
Description
Estimated Cost
12 V DC Gearmotor
$180
Material for Tooling
$60
Couplings
$5
Actuators
$30
Controls
$100
Rechargeable Battery
$30
Bearing
$30
Nuts and Bolts
$15
Cutting Blade
$55
ACME threaded rod
$30
ACME threaded nut
$6
Hinge
$3
Machining
$450
TOTAL
$994
LABOR
Description
Research
Design
Fabrication
Testing
Tech Expo
TOTAL LABOR
TOTAL LABOR COST ($25/Hour)
ESTIMATED TOTAL COST
Estimated Time
50 hr
100 hr
50 hr
20 hr
12 hr
232 hr
$5,800
$6,794
40
APPENDIX – C
CALCULATIONS
41
CALCULATION SPREADSHEET
I USED A LOAD UNCERTAINTY OF 3 TO ALLOW FOR SOIL
CONDITION CHANGES. IN THE FACTOR OF SAFETY SECTION YOU CAN
SEE THIS SPREADSHEET WITH THE FACTOR OF SAFETY OF TWO. THIS
SPREADSHEET DOES NOT INCLUDE THE FACTOR OF SAFETY.
Design Parameters
Cutter Rotation (deg)
Dia. Cutter (in)
Dia. Screw (in)
Screw Lead (in/rev)
Screw Efficiency
Normal Soil Force (lbf)
Tangential Soil Force (lbf)
Load Uncertainty
Travel (in)
Travel Time (s)
Motor Stall Torque (in-lbf)
Calculation Variables
Pin Tangential (lbf)
Pin Axial (lbf)
Screw Tangential (lbf)
Max Screw Tangential (lbf)
63
4.5
1
0.25
35%
66
19
3
7
9.88
302
57.00 Fts
20.15 Fsa
17.36 Ft
211.40
Design Criteria Values
α (deg)
70.54
Cutter Pin Normal Force (lbf)
60.46 Fslot(N)
Axial Screw Force (lbf)
218.15 Fp
Nut Torque(in-lbf)
8.68
Input Screw Torque (in-lbf)
24.80
Motor Torque (in-lbf)
24.80
Axial Cutter Speed (in/s)
0.71
Radial Cutter Speed (rev/s)
0.02
Screw Speed (rev/s)
2.83
Motor Speed (rev/s)
2.83
Motor Speed (rpm)
170.04
Motor Power (hp)
0.07
Worst Case Scenario
Max Axial Force (lbf)
2656.53
42
DIRECTIONAL SLOT FORCES
Fpush
Fts
α
F slot
Fsa
Fn
α = Tan-1 [7/(π (4.5)(63)/360)] = 71° (Design Criteria)
Fts * 3 = 19 *3 = 57 lbf (Calculation Variable)
Pin Axial Force
Fsa = 57lbf / tan (71°) = 20.15 lbf
Axial Screw Force
Fp = Fd + Fsa * load uncertainty
Load uncertainty = 3
= 66lbf +20.15lbf *3 = 218.5 lbf
Cutter Pin Normal Force
Fslot(N) = √(572 + 20.152) = 60.46lbf
43
THREADED ROD FORCES
Ft
Lead
Fpusher
Using a 1” – 4 ACME Threaded Screw and Nut
Efficiency of screw = 35 %
Coefficient of Friction = .15 (well lubricated nut and screw)
Screw Tangential
Ft = Lead / π(D) * Fp
= .25 / π (1) * 218.5 = 17.36
Nut/Screw Torque
T = Ft (D/2)
= 17.36 (1/2) = 8.68 in-lbf
Motor Torque = 8.68 / .35 = 24.80 in-lbf
(WITH UNCERTAINTY LOAD BUT NOT FACTOR OF SAFETY)
44
SIZING OF MOTOR
Motor Torque = 24.80
Axial Cutter Speed
Axial Cutter Speed = Travel / Travel Time
= 7” / 9.88 seconds = .71 in/s
Radial Cutter Speed
Radial Cutter Speed = cutter rotation / travel time
= [(63/360) / 9.88] = .018 rev / s
Screw Speed
Screw Speed = axial cutter speed / screw lead
= .71 / .25 = 2.84 rev/s
SCREW SPEED = MOTOR SPEED
Motor Speed in RPM = 2.84 * 60 = 170.04
Motor HP
Motor HP = motor speed * 2π * torque * (1/6600)
= 2.84 * 2π * 24.80in-lbf * 1/6600
= .07 HP
(WITH L0AD UNCERTAINTY BUT NOT FACTOR OF SAFETY)
45
WORST CASE SCENARIO
Worst case scenario would be if cutter hits rock.
Motor Stall Torque = 302 in-lb
Max Screw Tangential Force
Max screw tangential force = Stall torque * π * (D/Lead) * Screw
Efficiency
= 302 * π * (2/1) * .35 = 211.4 lbf
Max Axial Force
Max Axial Force = Max Screw Tangential * π * (D/Lead)
= 211.4lbf * π * (1/.25) = 2656.5 lbf
46
SOIL CUTTING CALCULATIONS
γs = 120 lb/ft3
(specific weight of sand)
π * 4.5 *(1/8) = 1.7in2 (area at bottom of cutter blades)
π * 4.5 * 7 = 99 in2 (area of cutting assembly)
Granular Soil Equation
Σ= γd
= 120lb/ft3 * (7/12) = 70 lb/ft2
Shearing Soil
Τ= μ σ
Friction coefficient = .4
= 70lb/ft2 * .4 = 28 lbft2
Friction Force
Pf = Τ * A
= 28 lb ft2 * (99/144) = 19 lbf
Bearing Force
Bearing Force = Τ * N q * A
= 70 (80) (1.7/144)
47
SHEARING OF BOLTS ON NUT/SCREW SLOT
(WITH LOAD UNCERTAINTY AND MAX FACTOR OF SAFETY)
FORCE ON BOLT
F=T/R
= 49.60 in-lbf / 2.5 = 19.83 lbf
SHEARING
V = 19.83 / [(π (.3752))/4]
= 179.62 lb-in
CONVERSION TO KSI & CHECKING FOR SHEAR
Convert to KSI = 179.62 / 1000 = .179KSI
.179 / 82.5 = .2 %
.2% /2 = .1 % (for 2 bolts)
BOLTS ARE FINE FOR NUT/SCREW SLOT. WELL UNDER THE
55% OF 150 KSI OF BOLT.
48
SHEARING OF BOLTS ON DIRECTIONAL SLOT
(WITH LOAD UNCERTAINTY AND MAX FACTOR OF SAFETY)
FORCE ON BOLT
F = 120.91 lbf
SHEARING
V = 120.91 lbf / [(π (.3752))/4]
= 1094.74 lb-in
CONVERSION TO KSI & CHECKING FOR SHEAR
Convert to KSI = 1094.74/ 1000 = 1.09 KSI
1.09 / 82.5 = 1.3 %
1.3% / 2 = .65 % (for 2 bolts)
BOLTS ARE FINE FOR DIRECTIONAL SLOT. WELL UNDER THE
55% OF 150 KSI OF BOLT.
49
POWER CALCULATIONS
USING 12 VOLT CAR BATTERY WITH 30 AMP HOURS
MOTOR
12 V
13.98 amps
ACTUATOR
12 V
3.4 amps
Pete’s Actuator 12 V
22 amps
RUN TIMES (IN BEST ESTIMATES)
MOTOR
TRAVEL TIME
10.7 seconds * 2 = 21.4 seconds (time to cut and extract plug)
21.4 seconds * 9 holes = 4 ½ minutes
Convert to hours (4.5 / 60 = .075)
13.98 amps * .075 = 1.05 Amp Hours
KYLE’S ACTUATOR
TRAVEL TIME
4 minutes * 9 holes = 36 minutes
Convert to hours (36 / 60 = .6 hours)
3.4 * .6 = 2.04 Amp Hours
50
POWER CALCULATIONS CONTINUED
PETE’S ACTUATOR
TRAVEL TIME
7.5 * 2 = 15 seconds
15 seconds * 9 holes = 2.15 minutes
Convert to hours (2.15 / 60 = .035)
22 * .035 = .788 Amp hours
ADDITION OF ALL EQUIPMENT FOR POWER USAGE
1.05 amp hours + 2.04 amp hours + .788 amp hours
= 3.878 amp hours
51
FACTOR OF SAFETY
A load uncertainty of 3 times the normal force was used in
the calculations. However, for safety purposes a factor of safety
of 2 was also used to go along with the load uncertainty.
All of the equations given besides shear calculations were
without a factor of safety. The following is the spreadsheet
without the factor of safety:
Design Parameters
Cutter Rotation (deg)
Dia. Cutter (in)
Dia. Screw (in)
Screw Lead (in/rev)
Screw Efficiency
Normal Soil Force (lbf)
Tangential Soil Force (lbf)
Load Uncertainty
Travel (in)
Travel Time (s)
Motor Stall Torque (in-lbf)
Calculation Variables
Pin Tangential (lbf)
Pin Axial (lbf)
Screw Tangential (lbf)
Max Screw Tangential (lbf)
63
4.5
1
0.25
35%
66
19
3
7
9.88
302
Shear Calculations
Nut Bolts
9.919694
Force on bolt (lbf)
Shear Stress (lb-in) 89.81438
Directional Slot Bolts
547.371
Shear Stress
57.00 Fts
20.15 Fsa
17.36 Ft
211.40
Design Criteria Values
α (deg)
70.54
Cutter Pin Normal Force (lbf)
60.46 Fslot(N)
Axial Screw Force (lbf)
218.15 Fp
Nut Torque(in-lbf)
8.68
Input Screw Torque (in-lbf)
24.80
Motor Torque (in-lbf)
24.80
Axial Cutter Speed (in/s)
0.71
Radial Cutter Speed (rev/s)
0.02
Screw Speed (rev/s)
2.83
Motor Speed (rev/s)
2.83
Motor Speed (rpm)
170.04
Motor Power (hp)
0.07
Worst Case Scenario
Max Axial Force (lbf)
2656.53
52
FACTOR OF SAFETY CONTINUED
The following spreadsheet is all of the calculations with the
Factor of safety of two times the load uncertainty:
Design Parameters
Cutter Rotation (deg)
Dia. Cutter (in)
Dia. Screw (in)
Screw Lead (in/rev)
Screw Efficiency
Normal Soil Force (lbf)
Tangential Soil Force (lbf)
Load Uncertainty
Travel (in)
Travel Time (s)
Motor Stall Torque (in-lbf)
Calculation Variables
Pin Tangential (lbf)
Pin Axial (lbf)
Screw Tangential (lbf)
Max Screw Tangential (lbf)
63
4.5
1
0.25
35%
66
19
6
7
9.88
302
Shear Calculations
Nut Bolts
19.83939
Force on bolt (lbf)
Shear Stress (lb-in) 179.6288
Directional Slot Bolts
1094.742
Shear Stress
114.00 Fts
40.29 Fsa
34.72 Ft
211.40
Design Criteria Values
α (deg)
70.54
Cutter Pin Normal Force (lbf)
120.91 Fslot(N)
Axial Screw Force (lbf)
436.29 Fp
Nut Torque(in-lbf)
17.36
Input Screw Torque (in-lbf)
49.60
Motor Torque (in-lbf)
49.60
Axial Cutter Speed (in/s)
0.71
Radial Cutter Speed (rev/s)
0.02
Screw Speed (rev/s)
2.83
Motor Speed (rev/s)
2.83
Motor Speed (rpm)
170.04
Motor Power (hp)
0.13
Worst Case Scenario
Max Axial Force (lbf)
2656.53
The motor torque doubles to 49.6 in-lbf. The motor
selected still meets these specifications. The shear calculations
in this spreadsheet were the ones used in the calculations.
53
APPENDIX - D
MANUFACTURERS SPECIFICATIONS
54
SHAFT COUPLING
55
SELF - CLOSING HINGE
56
Linear Actuator
57
3’ ACME THREADED ROD
58
ACME THREADED NUT
59
FLANGE MOUNT BEARING
60
FOUR SHOULDER BOLTS
61
12 VOLT DC GEARMOTOR
62
APPENDIX - E
MECHANICAL DRAWINGS
63
64
65
66
67
68
69