Self propelled lawnmower redesign

From DDL Wiki

Revision as of 00:28, 9 October 2008 by Dtorres (Talk | contribs)
(diff) ←Older revision | Current revision (diff) | Newer revision→ (diff)
Jump to: navigation, search


Executive Summary

In this report we will present our findings upon further analysis and brainstorming ideas to modify our Toro Self propelled Lawn Mower. Our report consists of Major Stake holders and Needs, Research, Design Concepts, Pugh chart, Gantt chart, Conclusions and Recommendations, Related existing products, In the Lawn care industry, there are various stakeholders; Manufacturers, Retailers, and Consumers. More detail as to specific needs of each stakeholder is elaborated in the Stakeholders needs section. In order to further understand where we could improve the self-propelled mower, we felt it was necessary to do research on use and maintenance of the product. To provide even more information, we sought out consumer and retailer feedback on everyday use and maintenance of the Toro self-propelled lawnmower. Based on the information and feedback gathered, we’ve concluded six areas of possible improvement; Vibrations and User Comfort, Difficulties with Bagging System, Stalling engine in long grass, Difficulties with maintenance and cleaning, Transportation and storage of mower, Safety issues. In Design Concepts, we’ve compiled a list of possible innovations that we felt were within our abilities based on the knowledge gathered in research and from our brainstorming sessions. We’ve briefly gone over our top 4 ideas which include a traveling hitch, garbage bag attachment, Suspension kits and a blade Tachometer. The details on each idea are further explained in the Design Concepts section. Our ideas were then analyzed and compared to our current product, a Toro Self Propelled Lawn Mower. Upon comparison to the datum, we discovered that two of our ideas were beneficial all around, 1 was slightly under par, and the third was a possible setback in overall rating of the mower. The results to this analysis are in the Pugh chart section. In our Gantt chart, we have listed milestone dates, and a possible schedule to keep us on track. We’ve listed our expected date of completion and have allotted a fair amount of time to finish the final report and still have time to modify our final design. In Summary, Our conclusion from testing and comparison is that the trailer hitch innovation would be the most beneficial at this time. It was the most balanced in benefit and thus the highest rated design concept.

Stakeholder Needs

The following is an updated list of the stakeholders involved with our product, and each of their needs.

1.) Manufacturer: The manufacturer is responsible for taking the raw materials shipped to them and processing them into a finalized product.
- The product must be easy to assemble to reduce time of assembly and subsequently, labor costs.
- The materials comprising the product must be properly selected so that each part of the product accomplishes its function, but at the cheapest cost possible.
- Cheap and efficient manufacturing processes like stamping/plastic mold injection.
- The product must also have easily accessible parts in order to fix them or replace them entirely.

2.) Retailer: The retailer is responsible for delivering the product to the consumer from the manufacturer.
- The product must be marketable --> In order for the retailer to sell the product to the consumer, the product must be captivating and aesthetically pleasing.
- In order to keep many of the products in stock, they must not be too cumbersome. This is also necessary for an effortless delivery to the consumer.

3.) Consumer: This group includes anyone who seeks to mow any lawn, ranging from lawn owner to commercial lawn mowing businesses.
- The product must be well secured and comprised of appropriate materials to ensure user safety.
- The product must be lightweight and so that any user can mow any type of lawn.
- Durability is required because the consumer can't always afford the time required to repair the product.
- It must be conveniently adjustable in order for the consumer to cut a lawn at whatever the desired height may be.
- In many cases, the consumer is required to move the lawn mower to another location, so it must be transportable.


Research 1

In our attempts to find areas for innovation we sought out different sources to diagnose problems with the current lawnmower design. Our first test involved the four members of the group. Each of us was given the opportunity to use the mower in a variety of common situations. These situations included mowing high grass, short grass, uphill, downhill, etc. We also had each member test loading and unloading the mower into a van/truck. Another test we had each member do was start and refuel the mower. Instead of immediately discussing our opinions and observations we wrote them down so that we would each have an unbiased opinion. We then compared the results and diagnosed the crucial problems. We discussed possible solutions to these issues and compiled a list. The key ideas were isolated and these became the ones that we will focus on.

Research 2

The next step in our market research was to go out and ask people who deal with lawnmowers everyday what problems they commonly saw. We went to a local lawnmower service and repair center to speak to experts about the project. We asked them what aspects of the lawnmowers they commonly complain about and their suggestions for improvements. They seemed to find the same problems as we did in our initial test and had very similar solutions. We showed them our ideas for innovation and asked for their honest opinions on feasibility. They liked some of our ideas a lot while others they said would probably not work or they had seen similar solutions that didn’t work. After performing this market research we were able to narrow it down to four design concepts. These concepts are all a direct response to complaints of the stakeholders and seek to resolve key issues with the lawnmower. They all seem to be feasible and within the scope of this course and our resources.

From both research studies we were able to compile a list of major flaws we found in the current design of our lawnmower. These categoreis were...

1. Vibrations and User Comfort

2. Difficulties with Bagging System

3. Stalling engine in long grass

4. Difficulties with maintenance and cleaning

5. Transportation and storage of mower

6. Safety issues

Then from these categories we began to brainstorm a list of 100 design innovations to remedy each problem. We found it easier to come up with innovations when we thought of them as solutions to stakeholder's problems.

Design Concepts

After our brainstorming process we began to narrow down our ideas. We weeded out some of the impractical and unfeasible ideas. We then picked some of our better solutions and arranged them in a chart based on the problem they helped resolve.

Vibrations and User Comfort Bagging System Long Grass / Stalling Maintenance and Cleaning Transportation and Storage Safety

Pneumatic Tires Garbage Bag Attachment Engine Tachometer Self Cleaning Deck Mower Hitch Attachment Key Ignition

Front and Rear Suspension Grass Compactor Blade Feedback Control Self Sharpening Blades Snap-together parts that can be easily disassembled Push-Button Starting

Rising/Retracting Turning Castor Wheels Rotating Discharge Chute Low R.P.M. Warning Light System Run Timer Foreign Object Recognition

Air Suspension Carbide Blade Tips Dashboard with System Check Lights Brakes/ Wheel Locking Mechanism

Concept 1

One of the most frequently stated problems our test audience came up with during our product research was the difficulty in transporting the lawn mower. We first identified that far less than even half of lawn mower users would even have access to and adequate vehicle to move the mower in. The second problem we addressed was if the owner had a moving vehicle was the difficulty in lifting the heavy mower alone. Lifting the mower into a truck bed required a lot of strength and power from the user. In addition the vehicle often became dirty from the gasoline, oil, and lawn clippings left behind. Another problem addressed was safely securing the mower in a vehicle, required many straps and bungee cords.

In this concept we solve many of the previous problems with our trailer hitch attachment. The hitch assembly is very simple and consists of 2 main parts. The first part is a hitch post (number 1 below) that would slide into the female fitting on the vehicle hitch. The second part would a channel bracket (number 2 below) that would slide onto the hitch post. This channel bracket would be mounted to the deck of the mower. When the user wanted to transport the mower all he or she would have to do is pick the mower up and slide the channel bracket onto the hitch post. There will need to be some further design to lock the mower in place, but the basic idea is established in the sketch below.

Concept 2

The garbage bag mower attachment is intended to remove the redundancy in the bagging process. In the normal lawnmower the bag that collects the grass clippings gets full and has to be emptied into garbage bags. This process can be messy and cumbersome. This redesign seeks to remove that transfer process by installing a rack at the rear of the mower which a garbage bag will rest on and collect clippings. When the bag is full it can be removed and replaced with ease, eliminating the need to transfer the clippings. The rack would likely be built of thin but strong steel bar and the garbage bags would ideally be generic. The rack would be attached in such a way that it could be easily removed.

Concept 3

An additional common compliant when using the self propelled lawn mower is the vibration the user feels in he hands and arms. These vibrations occur when the mower is passing over bumpy terrain. We decided that a good way to solve this problem would be by adding front and rear suspension to the lawn mowers wheels. We designed this by adding a small shock tower to hold the damper in place. We also added independent A-arms to allow the wheel to flex up and down, and to give the shock a place to mount. The rear design hasn't been completely thought out to this point, due to a few major complexities. We found that we would need a flexible drive shaft and hub carriers. Due to the complexities of this system we decided it might require more money and time than we had available.

Concept 4

Our fourth design was derived from the problem many people reported with cutting long grass and having the engine stall out. When the mower would get into too thick of grass the blade rpms would drop greatly. Then sometimes the engine would slow down so much that it would stall out. The user in many cases often found it hard to determine when the rpms were dropping too low, and in a few cases were not able to slow the mower in time to prevent engine stalling.

In order to remedy this problem we developed the idea of integrating a blade tachometer into the mower. We designed it similar to cyclometers found on bicycle speedometers. We decided we could attach a magnet to one side of the mower blade. We then would place a magnet sensor above the blade on the lawnmower deck. So then every time the blade would pass by the sensor it would count it off and be able to compute the blade rpms from this. We finally designed the system to have an easy to read tachometer display attached to the mower handle. We also thought about integrating a warning light that flash on the display when the mower's rpms dropped too low. We thought that this design feature would allow users to slow down or stop forward movement of the mower until the rpms got higher than the warning value.

Pugh Chart

In the following Pugh chart we decided to compare our 4 best innovations to each. We also compared them directly to the stock self propelled lawn mower. We used the weighting system of 0-5 to determine how important we felt each category was to the stakeholder. We made safety our biggest priority since the consequences of having an unsafe product could be detrimental to the user. We also chose to rate portability and cut quality high priority. We thought if the mower didn't produce the quality of cut the user was looking for, it would never chosen over other designs. Also we thought portability was a very high priority because many stakeholders rely on the mower to service more than one lawn. If the mower wasn't easily transported, commercial applications could be completely ruled out of our target sales group. We then used the +, 0 , and - system to rate each innovation in each category. Some of the standout +'s were the portability of the trailer hitch and the comfort of the suspension. Some of the major drawbacks pointed out in the chart were price of the tachometer and suspension kit, and the portability of the garbage bag system. These major perks and drawbacks had great influence on results of the chart.

Description Standard Self Propelled Mower Mower with Trailer Hitch Assembly Mower with Garbage Bag Attachment Mower with Suspension Mower with Blade Tachometer
Criteria Weight Datum Design 1 Design 2 Design 3 Design 4
Safe 5 0 - 0 0 +
Comfort 2 0 0 0 +++ 0
Portable 3 0 +++ -- 0 0
Usability 3 0 + + ++ ++
Durable 2 0 0 0 -- 0
Maintenance 2 0 0 0 -- -
Affordable 2 0 0 - -- --

Cut Quality 3 0 0 0 + ++
+ 0 12 3 15 17
0 24 13 14 10 7
- 0 5 10 16 10
Net Score 0 7 -7 -1 7

The results of our chart showed that the trailer hitch idea and blade tachometer proved to be viable options for our prototype. Both options tied with a net score of a 7 as compared to the other scores of 0, -1, and -7. After this chart we were able to narrow our possible prototyping down the trailer hitch and tachometer. At this point we eliminated the garbage bag attachment, and mower suspension from our study. We then reexamined the remaining ideas in search of our final proposal.

Gantt Chart

Conclusions and Recommendations

From our market research, Pugh chart analysis, and usability tests we've come to the general consensus that Concept 1 would be the optimal design for Prototype I. Most importantly, the Trailer Hitch Design (Concept I) scored highest on the Pugh chart. This concept scored greatest in the criteria of portability and usability, which encompass many of the issues consumers of this product most commonly face. Frequently, consumers must transport the lawn mower from one location to another, proving to be a tedious, arduous, and dirty process. Concept 1 solves all of these issues and would greatly benefit a vast array of self-propelled lawn mower users. Along with the resolution of these issues, we feel that this prototype provide a simple and cheap manufacturing process. With proper choices of material and manufacturing methods this design can be manufactured at a nominal cost. Compared to our other concepts, this design was more simple and yielded equally propitious user benefits. Therefore, it was the most prudent design choice for the first prototype.

Team Member Roles

Dave Torres: Executive Summary, Design Concepts, Brainstorming
Alex Kalberer: Design Concepts, Research, Pugh Chart, Related Existing Products, Brainstorming
Rich Zuckerman: Research, Design Concepts, Related Existing Products, Brainstorming
Graham Bannantine: Stakeholder Needs, Gantt Chart, Design Concepts, Brainstorming, Conclusion and Recommendations


The following is a list of initial ideas for innovation on the lawnmower. This was a general brainstorm and some of the ideas tend to be more abstract. Even so, they were able to hone our thought process such that we would come up with more feasible solutions.

1. Feedback system for blade

2. Battery powered

3. Cutting strings instead of blades

4. Turning front wheels

5. Rising casters for easier maneuvering

6. Leaf catcher/shredder

7. Grass incinerator

8. Grass watering device

9. Grass fertilizing device

10. More user-friendly/ergonomic push handle

11. Automatic throttle/choke control

12. System check light panel (similar to car dashboard)

13. Electric ignition

14. iPod dock

15. Cup holder

16. Brakes on wheels for steep hill cutting

17. Hill assist for steep hills

18. Stereo system

19. Run timer (to help schedule maintenance)

20. Baffled muffler (noise reduction)

21. Grass compactor for increased storage of cut grass

22. Side chipper/shredder

23. Hybrid engine system

24. Diamond tipped blade

25. Four smaller blades instead of one big one

26. Snap together parts for easy transportation

27. Integrated weed-whacker (clips onto side)

28. Mounting arm to attach directly to trailer/hitch

29. Line making system (check how straight cut is and keep in line)

30. Rotating side discharge chute (similar to snow blower)

31. Cell phone alert system

32. Headlights for night use

33. Fan, cooling system

34. Umbrella (sun/rain)

35. Compartment to store items (tools)

36. Remote controlled

37. Key ignition

38. Key code for safety

39. Cooler (drinks)

40. Cable locking system

41. Tracks like on snow-mobile for traction

42. Ball shaped steering design (roll any direction)

43. Leaf blower system

44. Riding skids

45. GPS (route storage)

46. Self cleaning (washing system)

47. Bike seat (riding)

48. Reverse drive

49. Hovering deck

50. Automatic blade sharpener

51. Timer ($ to charge client)

52. Multiple angled handle to ease pushing

53. Throttle control similar to motorcycle (or drive control)

54. Extra large fuel capacity (in reservoir)

55. Fuel level gauge

56. Turn screw system

57. Handle suspension

58. Blade tachometer/odometer

59. Front suspension

60. Make all wheels adjust at the same time

61. Integrated fertilizer spreader

62. Air suspension for wheels

63. Bagging system redesign (garbage bags)

64. Introduce compressor to belt that stores energy to lift ride height

65. Introduce system connecting wheel axles to frame that allow raising/lowering

66. Adjust blade height instead of deck height

67. Replace cables with wireless

68. Studs on tires for better grip

69. Tank treads instead of wheels

70. Engine kill switch if blade is more than six inches from the ground

71. Hand crank with mechanical advantage instead of engine

72. Blade is attached to spring so that hitting a rock won’t damage the engine drive shaft

73. Rear view mirrors to watch for monsters

74. Computer that remembers cutting routes and can reproduce them

75. Cruise control

76. Warning horn

77. Rake in front to prevent foreign objects from hitting blade

78. Hooks for easy storage

79. Blade angler for trench digging

80. Clippers instead of blade

81. V-shape with multiple blades for reaching corners

82. Flower sensor so it doesn’t kill flowers

83. Engine uses bio-fuel for efficiency

84. Weather radar/alert system

85. Leaf sweeper in front to clear path

86. Powered by bicycle pedaling from user

87. Emissions reduction for indoor mowing

88. Thatching/aerating system

89. Bump leveler to even out bumps

90. Weed puller/killer

91. Metal detector to search yard for buried treasure

92. Attachment for mowing over tree roots

93. Trailing vacuum to suck up clippings

94. Heater on handle for cold weather mowing

95. Windshield for eye protection

96. Spoiler for down force at high speeds

97. Air conditioning system for hot days

98. Teflon coated inner deck to grass build up

99. Ergonomic grips on throttle handle bar

100. Chariot attachment to ride behind mower

Related Existing Products

Toro's Newest Self-Propelled Line of Mowers Specifications

Honda's Current Self-Propelled Mower

Cub Cadet's Current Self-Propelled Mower with Caster Wheels

Personal tools