Group 16 - Craftsman Lawn Mower/RFP

Background

Group 16 consists of the following members:

Peter Penasack (Project Manager)

Peter is the owner of Apac Equipment, Inc. which sells mechanical equipment for process applications. He is studying mechanical engineering to improve his understanding of processes and designs to improve his sales skills. Peter plans to remain at his current position well after graduation.

Peter's Project Role Responsibilities are:

• Manage and delegate all work associated with the project.
  
• Keep project on task and on time.

Matthew Duggan (Reassembly/Disassembly Co-Lead)

Matthew attended Erie Community College where he obtained his Associates in Applied Science in Civil Engineering in May 2008. He came to The University at Buffalo in September of 2008 where he gained a knowledgeable background in architecture and business before selecting a degree in mechanical engineering. Currently, Matthew bartends at T.G.I. Friday’s while he works towards his Bachelors degree. After Graduation, Matthew plans to continue expanding his education and experience to meet the requirements for the P.E. exam, where upon completion hopes to run his own private engineering firm.

Matthew's Project Role Responsibilities are:

• Identify necessary tools for reassembly process.
  
• Assist with disassembly.
  
• Inventory components during reassembly process to gaurantee that all components have been placed back in the unit.

Adam Lloyd (Disassembly/Reassembly Co-Lead)

Adam has earned his Associates degree in Engineering Science from Erie Community College and is currently in pursuit of his Bachelors in Mechanical Engineering at the University at Buffalo. In addition to being a full time student, Adam works part time for the Delaware North Company and is an active volunteer fireman. He hopes to obtain an internship over the summer, before he graduates, to receive valuable work experience in engineering. After Adam graduates with his Bachelors in Mechanical Engineering, he plans to pursue work in the field while also continuing his education with a Master’s in Business degree.

Adam's Project Role Responsibilities are:

• Inventory all items/components during disassembly process.
  
• Identify necessary tools for disassembly.
  
• Assist with reassembly.

Alex Elhage (3D Modeling Lead/Photographer)

Alex is a sophomore in the Mechanical Engineering department and currently works part-time for the department. Alex also plans to complete a minor in Computer Science. After his anticipated graduation in 2014, Alex plans to attend graduate school and pursue further education in mechatronics. Alex hopes to be able to assist in research during his undergraduate career at UB in order to gain experience that will be helpful as a future graduate student and employee.

Alex's Project Role Responsibilities are:

• Photograph all product components and disassembly/reassembly process.
  
• Create 3D models or all necessary components.

April Bouquard (Wikipage Coordinator/Communication Liason)

April received her B.S. in Elementary Education from Buffalo State College in December of 2003 and an Ed.M. in Literacy from the Univeristy at Buffalo in December of 2006. She is currently working full time at a local engineering company as a Program Analyst and earning her B.S. in Mechanical Engineering from the University at Buffalo. Upon completion of her degree, April would like to continue employment at her current company as a Product Engineer or Process Manager.

April's Project Role Responsibilities are:

• Create the Wiki page and edit all material that is posted.
  
• Point of contact between professor and group.<alleney@buffalo.edu>

Time Management

Diagram 1: Gantt Chart

The Gantt Chart above shows when each task and sub-task should be started and completed to make sure we complete the project on time.

Meetings: We will meet every Monday and Wednesday after class from 5 p.m. to 7 p.m in Capen Hall and as needed throughout the rest of the project.
Conflict Resolution: Any conflicts will first be resolved within the group. As a group, we will evaluate any issues and try to formulate a plan of how to resolve the issue. The group leader will be responsible for adddressing conflict issues, but each member of the group will have the opportunity to voice concers to the team. If we are unable to resolve the conflict among the group, we will seek the help of either the TA or Instructor.

Group Analysis

Referring to Table 1, it can be seen that Group 16 has the skills necessary to complete the project. These skills include:

• A public speaker
• Individuals with strong technical experience
• An individual with prior 3D modeling experience

But, the two main flaws of the group are time management and organization. To make sure these weaknesses do not impact the project there is a specific schedule that is to be followed, as well as, an individual responsible for tracking all class documents.

Table 1: Group Analysis

Pre-Dissection

Initial Product Assessment

Device: Craftsman 6 HP 21 inch lawn mower. Please refer to Table 2 for the product specifications.

Table 2: Product Specifications

Section 1: Development Profile
This product was manufactured in 1999 and its primary function is to trim grass in suburban areas with lawns of about an acre or less. It was designed to be used by the average consumer and was not intended for commercial use. It was designed for use in regions that are generally humid and receive moderate levels of rain allowing grass to grow. This product is in the mid-range price point, which allows it to be affordable to many middle class income families.

Section 2: Intended Usage

• Intended Usage- The product is a relativity easy to operate landscaping tool. It is used to cut grass to different heights while collecting grass clippings.
• Intended Market- The simplistic design and user friendly handling allows the lawnmower to have a relatively diverse market of operators. The push lawn mower's affordability and maneuverability make it ideal for smaller lawn homes.
• Job Performed- This product's base function is cutting grass. Features such as the grass catching bag and mulcher add the ability for the operator to perform multiple jobs. The four-stroke 6-horsepower Craftsman engine gives the operator adequate power to tackle difficult landscaping jobs.

Section 3: Energy Profile

In a lawn mower, the primary energy input to the system is gasoline, which contains stored chemical energy released open combustion. The desired output is rotational kinetic energy, which is meant to rotate the cutting blades and cut the grass. There are many intermediate steps, however, as shown in Diagram 2. A more detailed description of these steps can be read below the diagram.

Diagram 2: Engery Flow

1. There is a mass transfer of gasoline into the gas tank where it is stored for use.

2. The operator pressing the primer bulb generates pneumatic energy.

3. Pneumatic energy is used for a mass transfer of gasoline into the carburetor where it is mixed with air.

4. The operator opens a valve from the handlebar which allows a mass transfer of gas/air mixture into combustion chamber from the carburetor.

5. The operator pulls on pull start cable, generating rotational kinetic energy in the crankshaft.

6. The rotating crankshaft pushes the piston to generate linear kinetic energy.

7. Chemical energy from the gas enters the combustion chamber where is compressed by the linear kinetic energy of the piston, releasing thermal energy and exhaust, and generating linear kinetic energy in the piston through the expansion of air.

8. The linear kinetic energy of the piston is converted to rotational kinetic energy of the crankshaft.

9. The rotational kinetic energy from the crankshaft is utilized in rotating the cutting blades of the lawn mower.

Section 4: Complexity Profile

Components used:

There are an estimated 250 components used in this lawn mower which are incorporated into four major subsystems. They are:

• Controls
• Blade Housing
• Motor
• Push Arm

Components complexity:

Component complexity is based on four categories: geometry, manufacturing, size and interactions. The following matrix, shown below in Table 3, grades each subsystem on a scale of one to five, with five being the highest, in each of the complexity categories:

Table 3: Complexity Matrix

• The controls subsystem consists of a pivot bar that takes input from the user and transfers that information to a valve which controls the intake of fuel and air into the combustion chamber. Controls are small in size and require a low level of manufacturing, but are critically important in the interaction between the human and the machine.
• The blade housing is made from cast aluminum. It requires a medium level of manufacturing, and is one of the larger subsystems on the lawn mower.
• The motor operates on a four-stroke cycle and requires a high level of interaction between internal components to function. A high level of manufacturing is required, and mass-wise it is the largest subsystem.
• The push arm consists only of formed aluminum bars. They provide interaction between human input and the body of the lawn mower to push, but this is a relatively unsophisticated interaction.

Section 5: Material Profile

Main materials that are clearly visible:

• The four-stroke 6 HP Craftsman steel engine block houses engine parts
• The paper air filter with plastic housing traps dirt and sediment from air before being introduced into the engine
• A steel muffler reduces sound of the exhaust gases by passing them through baffles
• The steel carburetor mixes the gasoline and air for combustion
• Throttle with steel spring and bracket controls amount of fuel-air mixture
• Engine oil cap and reserve are both plastic
• Plastic gasoline tank with cap
• Steel lawn mower housing protects operator from spinning blade with plastic mulcher door
• Four plastic hubs with treaded rubber tires
• Mesh fiber grass catching bag
• Foldable steel operator handle with throttle control bar
• Plastic starter handle with pull start cord

Main material not visible:

• Steel piston/cylinder
• Primer used to inject small amount of gasoline into carburetor for cold starts
• Steel blade
• Steel drive shaft
• Steel gears connecting power of engine to spinning blade

Section 6: Interaction Profile

The user interface to the lawn mower is not overly complicate but, there are step that must be taken for proper operation of the mower. The order of these steps is important and they are vital to safe operation of the mower. The steps used to properly start the mower for example include:

1. Depress the red primer ball fully five times (not needed for a warm engine)

2. Hold the operator presence control bar down to the handle

3. Pull the starter cable not allowing it to snap back

4. The mower will run until the presence control bar is released to the up position

As you can see the day to day operation of the mower is not very complicated and is quite easy. Although this is true there are some things that you may not be equipped to do at home without the proper tools and training. Things that should be completed on a regular basis for proper maintenance of the mower and engine are shown below in Table 4:

Table 4: Maintenance Schedule

This is a basic maintenance schedule for the home owner. If you are not trained to perform these tasks, please consult a trained professional. If there are any other problems with the unit, you should consult the owner’s manual or your local retailer for professional repair.

Section 7: Alternative Products

Table 5 shows the specifications, advantages and disadvantages of four different alternative products.

Table 5: Alternative Products

Anticipated Tools Required

The following tools will be needed to complete the disassembly/reassembly of the product:

• Gloves
  
• Safety glasses
  
• Metric open end wrench set sizes 8-15 mm
  
• Philips Head screw driver sizes #1, 2, and 3
  
• Flat Head screw driver sizes 2-7
  
• 1 pair of 9 inch Channel Locks
  
• 1 pair of Needle Nose Pliers
  
• 1 pair of Diagonal Pliers
  
• 1 claw hammer (16 oz)
  
• 1 Ball Pein hammmer (8oz)
  
• 3/8 inch ratchet wrench with socket sizes 8-15 mm
  
• 1 broom
  
• 1 hand brush
  
• 10 inch bar for extra leverage on the wrenches

Dissection Plan

This dissection will not just be a complete tear down of the mower. Along the way, our team will be observing and recording how all the components of the mower interact and contribute to the operation of the unit. Throughout this process, we will be learning and understanding how the mower functions. To make it easier to reference and describe, we will be numbering and taking photographs of all the parts we come into contact with.

Separation Plan: (1 hr)
1. Clean the lawn mower of any loose debris
2. Drain the oil from the mower
3. Remove the blade from the bottom
4. Detach cable from handle to engine
5. Remove the bolts holding on the engine
6. Place engine on side for later dissection

Mower body plan: (1 hr)
7. Remove the wheel brackets from the frame
8. Remove mower handle
9. Remove bag door and springs that function it allow with side door
10. Remove any remaining parts still attached of frame of mower

Engine Plan: (3 hr)
11. Twist off the air filter
12. Remove the spark plug
13. Remove plastic cover off the engine
14. Unbolt and remove the exhaust system
15. Remove and examine the throttle control unit
16. Pull off engine gas line
17. Detach and remove the gas tank
18. Unbolt and remove carburetor cover
19. Disassemble carburetor
20. Disassemble and examine the pull start system
21. Disassemble and examine the drive shaft system to the blade
22. Open up engine cylinder and drain any remaining oil
23. Remove the piston and crank
24. Pull/unbolt all remaining components remaining on the engine block

Main Page

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References

[1] Moran, Michael J., & Shapiro, Howard N. (2008). Fundamentals of Engineering Thermodynamics: Hoboken, NJ: John Wiley & Sons, Inc.
[2] "Owner’s Manual Craftsman® 6.0 Horsepower 21” Multi-cut Rotary Lawn Mower." Hammerwall.com. 03 Oct 2011 <hammerwall.com>