Dolly 2.0 Final Report
Blake Savas, Kene Thornley, Tommy Nguyen, Tryston Taylor
Jordan Applied Technology Center
Engineering Design and Development
For the Engineering Design and Development class, we were to learn the design process. To do so we were split into groups and assigned to come up with a problem in the world that could be solved with technology. When we had decided upon a project we were to design and build a prototype to solve our problem. When the prototype was built it was to be tested thoroughly in order to prove conclusively that the project solved the problem. Throughout the entire process we were to maintain an up to date recording of all of our data and results as well as other documentation.
Table of Contents
Test Reflection 1
Why Buy the Product 3-4
Current Solutions 7-9
Design Specifications 10-16
Schedule/Gantt Chart 17
Concept Development 17-22
Prototype Design 23-26
Build Procedure 26-29
Test Reflection 35-37
Participant Feedback 37-38
Evaluation of Prototype 43
We were given instruction to create a solution for an everyday problem, one that does not currently have a solution, or improve an existing solution. There was no limit on how complicated the problem had to be, as long as a solution could be made to solve it. In this project we worked as a team to come up with a problem, design, and build a solution to that problem. We followed the design process step by step to help us achieve the best possible solution for our project. In this report, we outline each step in the process for beginning to end, finishing with the final design and results of our project.
Most often disabled, injured, or elderly, people have difficulty or are unable to transport their city provided garbage can down their drive way to the curb. When doing so they put themselves at risk of injury.
Statement of Purpose
Create a mechanical device to attach to a trash bin that enables users to move their trash bin without risking injury and without having difficulty doing so.
During the research phase of our project while we were exploring the main problems with moving trash bins, it came out that there are and have been serious injuries resulting from standard operation of a trash bin. Our device will make the operation of a trash bin relatively easy for most any user. Moving a trash bin from one location to another will no longer need be a risky and dangerous task.
According to research conducted in Australia, garbage bin injuries occur frequently to the elderly and in most cases require hospitalization, most injuries that are documented occurred with elderly patients around the age of 75. In an Australian medical journal, The Herald, researchers concludes that elderly people are at risk of injury, mainly around the age of 75, and the researchers also concluded that a re-design of the bin handles or help with moving the bins would be necessary to solve the problem.
In another case a man confined to a wheelchair displayed the need to have assistance moving a city provided trash bin down to the curb, especially in the winter. This man leaves his trash bins outside and in the winter snow sometimes gets in, on, and around the wheels, freezing them in place and making the trash bin immovable for him.
In yet another case an old man was injured moving his trash bin down to the curb. His trash bin was very heavy and as the elderly man was moving the trash bin down his long gravel drive way, the trash bin quickly moved into stationary position (carried by the weight inside the trash bin) and the elderly man was thrown over the bin. He sustained minor injuries such as bruised ribs and legs and a broken arm.
Figure 2-Injured Elderly Man
To discover how our product could be marketed, we first wanted to narrow down exactly who our device can help and how it can help them all in different situations. Because our device can help most anybody we were forced to narrow our target consumer market to acquire a small pool of people who it would help the most. We listed those consumers along with how the device would help each of them most. The information is listed on the next page.
Buyers Injured Persons Disabled Elderly
Users Persons with basic injury Those with permanent injuries Anyone
i.e. Broken Arm i.e. muscular dystrophy over age 60
Description Even with a broken arm or The dolly 2.0 acts as a stabilizer Muscle weakness
leg a user can operate our for both the trash bin and the does not matter,
dolly 2.0 user, making vertigo and other hardly any force
similar disabilities manageable is needed.
Chart 1-Target Market
Buyers: This chart represents the three major buyers of the dolly 2.0. Those people who have an injury such as a broken arm, those who are disabled with permanent injuries such as muscular dystrophy, and those who are elderly by our standards (over age 60) who have weak muscles.
Users: Most injured people will not need to have use of our device due to short injury time, however if it is a long term injury our product will become useful. People with physical disabilities will have use for our device because it could help them do a physical task that would otherwise be physically impossible for them to do. Those who are elderly may find use in our device because they may wish to retain their independence in their old age and may not desire assistance from others when doing basic things, such as moving a trash bin.
Why buy the Product? As an injured person it is sometimes difficult to move various objects around, let alone a heavy trash bin. An injured person would purchase this product because the need to move their trash bin while injured and may find that when they recover that they will continue to have use of the dolly if ever their trash bin becomes too heavy for them to move. A physically disabled person would have difficulty moving objects period. With assistance from our dolly, in certain cases a user would find the product very useful and may also make their life easier for them in a small way. As one becomes older it becomes more and more difficult to move heavy objects and as one loses the ability to do so they can no longer take care of themselves. The dolly 2.0 eliminates one area where they may no longer be able to do something for themselves; moving a trash bin down to the curb.
To ensure that the market we selected for our target market had a true desire for use and purchase of the dolly 2.0, we took a survey and held interviews in a few neighborhoods located in the West Jordan. The survey and interview were meant to discover whether or not our product was both a viable solution as well as one that is marketable. The results and content of the survey and interviews are as follows.
Survey: Market Survey conducted in West Jordan, Utah
A fifty person interview that determined whether or not we felt the problem was justified according to users.
- Have you ever had a difficult time moving a garbage can from one place to another?
- Yes No
- 45 People, or 90% 5 People, or 10%
- If yes, was the trouble due to the garbage can being too heavy?
- Yes No
- 36 People, or 80% 9 People, or 20%
- Would a device to assist you in moving the trash can help?
- Yes No
- 41 People, or 82% 9 People, or 18%
- Would you buy such a device?
- Yes No
- 29 People, or 58% 21 People or 42%
- If the device also had other uses such as a dolly or other lifting assistant, would you buy the device?
- Yes No
- 37 People, or 74% 13 People, or 26%
Data graph and explanation on next page
In this survey we obtained information from a wide range group of people, all of which have or do regularly operate a trash bin. From the information on this graph we gathered that moving trash bins is an actual problem in the eyes of the consumer. We also felt that the data confirmed that the consumers felt that our dolly could help solve the problem and that they would consider paying for such a device.
Interviews: Interviews held in the Sandy Utah area
These questions were the standard for all interviewees.
1. Have you had trouble moving trash cans and if so have you had any major incidents?
2. Have you had any major incidents with heavy objects like a washing machine or heavy box?
3. Would you buy a device that would help move your trash cans?
4. Would you buy the device if it was made for lifting other objects and/or had other uses?
Standard responses picked from 10 interviews
1. They have had trouble moving heavy trash cans before but no major incidents that they remember.
2. They have had incidents with heavy objects before.
3. They would not buy it if the device only had one use, that being moving trash cans.
4. They would buy it if it was made for heavy objects in general, like a dolly.
From the information gathered we found that the dolly would be successful but not to the extent we would have liked. As a group we decided that the dolly needed to have extra features that no other dolly has and possibly have the dolly be versatile enough to be used for other things.
When we added this information to the questions, we received a more positive feedback than we had previously with the dolly only having a base function.
From the interviews we further confirmed the data gathered from the surveys, that being that our dolly 2.0 was a viable project and that the problem of moving trash bins was worth solving, in the eyes of the target market.
Various versions of the dolly have been made throughout time and thus we are far from being the first people to make an attempt at innovating the dolly to make it better to fit a specific need. The inventions that follow are existing solutions to the problem but do not solve the problem as well as we would like. We hope to take aspects from each of these dollies and add a few improvements of our own to make the dolly as functional as possible. Each idea is listed below with a description of the device, and well as why we think our device would perform better.
Existing Product: Wheelie bin mover
This concept of the dolly is specific to a certain model of wheelie bin, or trash bin, and only operates within the parameters of that model trash bin. It uses two levels of hooks and two different attachments to secure the trash bin onto the dolly. When the dolly is in place it is locked in and the parts attachments must be removed when removing the trash bin.
-It solves the unique problem of moving a specific trash bin
-It is very effective within the parameters
of the trash bin that it is designed for.
-It is not versatile in and way
-It requires assembly with
attachments to hold the trash
bin in place
Existing Product: Stair Climber Sack Truck
This version of the dolly uses a tri wheel concept that allows it to climb up and down stairs. The three wheels rotate around the main axis and act as the main traction for the dolly. When the dolly encounters a bump or a stair, the wheels rotate to wrap around the bump or stair, allowing the dolly to continue to roll. This concept is a great solution to part of the problem but it is also very expensive due to the design of the wheels.
Figure 4&5-Stair Climber Stack Truck Isometric and Side views
Can climb stairs and over bumps easily. Does not attach anything.
Can be used for many different objects. Very expensive.
Existing Solution: Gas Cylinder Trolley
This dolly uses the pull out wheels design to create a stable movement for the gas cylinder. The operator does not have to support the load at all. If the operator wants to climb a curb with the trolley they simply push back on the handles to raise the front wheels. We took the idea for an extra set of pull our wheels from this design. We found that it would be the best way to move a load without having to bear the weight of it.
Figures 6&7-Gas Cylinder Trolley Operation Views
Enables user to move load without bearing Only able to transport Gas Cylinders
weight. Has no scoop to hold anything of any
Easy to attach load to dolly. meaningful size
Now that we have a full understanding of the problem and current solutions to the problem, an outline for the design is needed. In order to create the best possible solution to the problem, aspects from each of the other designs must be combined and entirely new features must be added as well. As a team we listed the criteria for how the dolly should perform and what specific types of features that it needs. The criteria are as follows.
Size and Weight
The size and weight of our device will be corresponding to the sizes of several other devices already being readily made today. The reasons these constraints are being used is, our device is meant to be compatible with these other devices and so it MUST correspond to their sizes. Because of these constraints the size may only vary within, and not without, the sizes ranging in; 43 and a half inches, to 45 inches in height, 24 inches to 22 inches in width, and 33 and a half inches, to 34 and a half inches in depth. Also the devices weight is wanted to fit within a restraint of our ideal, 25 Lbs., with no more variation in the overall weight than plus or minus 3 pounds, which is 22 to 28 lbs. respectively.
Though not always very pleasing to the eyes of most, to an engineer a well-designed implement or device will be well appreciated. What most people are looking for is the effectiveness of the common tools found in most hard-ware stores. By this state of thought I believe performance, ease of use, and looks, all fall under the definition of aesthetics. And so we will make our device as best we can to have fewer edges to create less wear in the users hands, and make the greatest mechanical advantage possible with the tools and time we have. Also we want the device to be useable in several applications, not just wheelie bins, so as to increase the amount of time the device is used, and thus the amount of time the person would spend with this device in their presence to assess the aesthetics each time. We will also like the implement to be partially treated, so the material will not deteriorate as quickly.
The material used in the creation of any invention, or innovation is crucial to the performance outcome of said device. Because of this we cannot allow the use of just about any material. The material we are looking for must be light and easily formed, malleable. Also we would prefer that the material will not be very expensive, but not so cheap that it is probably worthless. Working within said preferences above the preferred material will mostly likely be a formed alloy. One of the most common alloys that would be used for this would be aluminum, or titanium. Because of the price costs on titanium we will most likely be going with aluminum, and while light, this is also a fairly strong material. We prefer it be solid and not hollow as this promotes bending, and want it to be at least 1/6 inch thick.
The ergonomics of the product consist mainly of the handles and handle grips in order to give the user an easier time of maintaining control of the product while it is in use and to minimize the stress put on the hands that is created from using the device while it has a load. The handles will be angled and designed for in use ergonomic function so that the design is easiest to use while it is being used for its intended purpose which is to carry heavy loads easily and efficiently. Ergonomic design also pertains to the 4 wheel design which gives the product more stability and ease of use for the user of the product. The first set of wheels are the pivot point for the device which is where the initial load is placed, the second set of wheels are purposed for in use activity as it provides and angle that the entire load rests on and creates a very stable and controlled device while it is in use. By creating a stable and easily controlled design the product allows for easier use and a more efficient time while lifting and transporting heavy objects from one location to another. The device will provide the best mechanical advantage along with ease of use that we can provide as to make the job easier for the user overall. Turning mechanism for easier maneuvering is being considered.
The operating environment of the device constitutes of average environment change and standard weather patterns. The device CANNOT operate within extreme heat or cold such as in flames, the heat from a welder, being soaked in water and then frozen, liquid nitrogen, and other extremes that may break or damage the device significantly, damage to the device includes broken components, inability to function properly due to issues in the device itself due to wear and tear, abuse of the device, and unforeseen complications, damage to the device also includes complete destruction of the device. Difficulty may occur in snow covered terrain, icy pathways, rough terrain such as stairs or gravel covered roads, and or on natural terrain. Operating environment would be best in average weather on pavement, indoors on carpet, and in the bed of a moving van. The operating environment should be most consistent with heavy objects, specific instances include moving to a new location, moving a heavy object, moving a heavy trash can, or transporting many items at once by using the device.
This product is meant to last the entire lifetime of an average user, that average being thirty to forty years. This is assuming that a user would not consider buying this product until they reach the age of twenty at the earliest. The main users of this product however are people over the age of fifty, meaning that if a person were to live to ninety, this product would last them at least until that age.
The main components of service of this product are the overall care of the product, meaning that it should be kept out of all extreme conditions for maximum lifetime usage. The brake pads, which may need to be replaced every five to six years depending on how much they are used, which is an individual variable that will need individual attention for every user. The final service component is the needed replacement of lost or broken parts such as a nut that may fall off due to excessive usage or a wheel that may deflate due to excessive use. There may be other unforeseen product errors that require the user to replace a missing or broken part; the previous two are just examples of something that may occur.
Aspects such as service life of the steel used to build the dolly 2.0 must also be considered. The service life of steel pipe depends upon rates of external corrosion and internal abrasion. The service life can be increased by the use of proper coatings and cathodic protection. Technology for control of corrosion is available and well documented. With attention to coatings and cathodic protection, the service life of steel pipe can be extended indefinitely.
The dolly 2.0 is meant to be an innovation that will not need any improvement on the overall design in the future. Because the design is already an innovation, it is unlikely, however not impossible, that it can and will be improved upon in such a way as to make the previous design obsolete. Foreseen changes include the possibility of a new tire design being implemented on the dolly 2.0. If a new material was discovered that was in the same price range as the material being used to make the current dolly 2.0, and therefore would not make the design any more expensive, and had better attributes such as better strength and durability, the material may then be implemented in the design. Perhaps someday new structural designs may come out that would make it possible for the dolly 2.0 to use even less material, in which case the designs would be applied to the dolly 2.0 to make it cheaper while still maintaining its structural integrity and purpose. These are the foreseen changes in the way the product may be made.
However, it is estimated that the overall design of the dolly 2.0 will not change in the foreseeable future. The components that make up the design may be innovated and applied to the design to make it stronger, cheaper, or both, but the design itself is not expected to change.
The dolly 2.0 is meant to be made of high strength carbon steel. The material has proven to be extremely strong and durable against most conditions, even some extremes, when put into use. The high strength of steel results in lightweight pipe that can resist internal pressure, and can also resist external pressure when the pipe is not pressurized. Higher strength steels are available but would make the product too expensive for the average consumer. Longitudinal strength (beam strength) of steel pipe is of value wherever the pipe is subjected to variable loads or is supported on non-uniform bedding, such as when the steel will be put under pressure from the various loads that are meant to be put onto it while the product is in use. The high strength of steel and the low Poisson ratio and coefficient of thermal expansion/contraction, combine to make steel pipe relatively resistant to longitudinal stresses. Because of its toughness, steel can tolerate considerably more deformation than less ductile materials. Toughness is measured by the area under the stress-strain diagram. Steel is tough because of the wide ductile range and the high ultimate stress which is over 65,000 psi for typical pipe-grade steel, which is only slightly higher than the steel being used to make the dolly 2.0. Brittle material that fails at yield stress has toughness only within the elastic range. This is the resilient range wherein the material rebounds when unloaded. Strain of steel at elastic limit, often referred to as the proportional limit, is 0.14%. These attributes allow for much reliability and versatility in the material being used to make the dolly 2.0.
This product is meant to last a very long time. One should be able to put it through just about any type of longitudinal stress that is over extraneous. There are exceptions to every rule and there are bound to be situations that cause the device to break, however, it is built to withstand extreme situations and those situations that would most likely break the device would fall under the category of non-liability on the part of the design.
The standard need of consumers who uses curbside waste containers, for them to fill the container, not be able to spill, and it is manageable to carry to the curb for Waste Collection trucks. There are three types: trash cans (receptacles often made of tin, steel or plastic), dumpsters (large receptacles similar to skips) and wheelie bins (light, usually plastic bins that are mobile). For a small residential zone, the typical containers are trash cans, while for a larger residential it is the wheelie bin. The dumpster is primarily for urban residential zones like apartment buildings.
The design made as an innovation to the waste containers with the exception of the dumpster, the customer wants it to be easier to move the trash bins/wheelie bins to the curb. The device is able to support the from a 120-240 liter range of waste. If the device has a concept like a hand truck, the wheels can lock so that the bin does not fall over, under weather conditions or at a steep slope, including a mechanism to slow down if the bin is pulling the user down. Also it has a handle or grip that they can hold to move it, than the frame itself. The device has a way to attach and detach the bin to it to be more secure, when moving it. For a general populace that the device could be design so that it is universal for any type of bin they have.
The design objectives behind the bin were efficient use of space and safety: to provide at least as much space as the older round bins, while reducing the risk of injury caused by moving it. This is important for both the householder and the waste collector, who risked injury through lifting the traditional bin or from sharp or possibly contaminated objects in garbage bags. The early standard for these bins was the German DIN Standard 30740 and DIN 30700 parts 1 + 2 and later RAL-RG 723/2, but the European Union the specification of wheelie bins is now governed by the European Standard EN840, Part 1 of which covers the construction and dimensions of two wheeled bins with a range of capacities.
The performance of the device is to be assisting the householder to move their bins to the curb without a less risk factor. Device must be having a general dimension to fit each type of bins (except the dumpster). Dimensions for bins ranges from 3ft x 2ft x2ft to 4ft x 2ft x 3ft. Device must be at angle when in place of moving the bin. It is at a 3-4 degree angle. Device must have a strong frame capable of holding up to 240 liters of trash. Drive must have a scoop that can support a 240 liter bin. Device must have an attaching and detaching slide for each different kind of the bin, and is capable of securing the bin while moving. Device must support the bin to stay at the curb without falling or slipping at a steep slope. Also be able to slow down when moving the bin with a heavy bin or if it is at a steep slope.
Prototype: The initial design will be build out of already existent materials. The frame will be created from a hand truck (Standard hand truck varies from $50-60). Wheels are $5-10. The Hook mechanism is going to cost of $20-30. Brake system is $5-10. Parts of the frame are going to be $10. Total amount is going to be $80-120.
Final Product: The final design will be build out of raw materials. Frame structure is made out of ½” SCH 40 9.840 OD X .109 wall) A-500 ERW Structural Carbon Steel Pipe is $30. Wheels ranges from $5-10. Hook mechanism is $20-30. Brake system is $5-10. Total is $60-80.
Safety and Legal Issues
The safety and legal issues involved in the dolly 2.0 consist of any sustained injury while using the device, any damage caused to property owned by an individual or organization, any damage caused to the load while product is in use, any design flaws that may cause issues in situations, any components that break easily or quickly, any pieces or components that degrade quickly or become fatigued over a relatively quick period of time, any loose or free hanging components that can snag on other objects. Product testing will require extensive testing on all parts of the product including live user testing in which a wavier will be required in order to test and use the product during the testing phase of the project, wavier included at the bottom of this specification. Product must be safe enough for anyone physically capable of using the device so that the user does not sustain injury while using the product or cause damage while using the product.
To help keep the team on track with what needed to be done in the project in order to be done on time, we came up with a Gantt chart. This chart lists out every activity we did throughout the project, and the time allotted for each activity. This was used to keep us from straying too far from where we needed to be or spending too much time on any given part of the project. The key sections of the project were the research of the problem, justification of the project, design and build of the project, testing of the design build prototype, and documentation for final presentation. Further information and more detail can be found in the actual Gantt chart in the appendix.
As a group we had basic ideas for what we wanted to do. We knew that the design would look like a dolly but other than that we had no idea what we were going to do with the design. We started out with a verbal brainstorm, not really writing ideas down as we went but all taking mental notes as the discussion went on, taking the parts and ideas for the dolly that we each liked. We each took those ideas and made a group sketch to get us started. We would then take this sketch and assign out different sections of the dolly to design. Each member would then sketch their section and computer design would commence from there.
When starting this project, prototyping was a major objective to be accomplished. We had to figure out what parts we could actually put into place in our prototype to fit our budget and desired for function. We had a few parts that could not be added to the prototype because of time and money constraints, but most of the parts made it into the prototype build design. We chose the main features of the design that were unique to our dolly to assemble and build.
Bonus Wheels: The idea for the bonus wheels came from one of the designs for a dolly that had been previously designed and used for another purpose, the Gas Cylinder Trolley. They are similar in that the bonus wheels extend out and are used to bear the weight of the dolly and are used by the operator to push the dolly into moving position. We took this and adapted it to our design by making a few slight adjustments. Those adjustments comprised of a change in the length and position of the bars relative to the dolly, an extra bar in the middle for support and retraction use, and a different locking mechanism for the bracket section of the bonus wheels.
Hooks: The idea for the hooks came from the need to not have any removable parts on the dolly. In the dolly design Wheelie Bin Mover, there are parts that must be attached and removed in order for the dolly to function fully. We needed a part that would remain on the dolly but could also move and adjust to many different types of residential trash bins. Originally we wanted to have a belt to attach the trash bin to the dolly and have that belt enclosed in the Retractable Belt Casement but this proved too time consuming to build and put onto the dolly and too expensive to buy. Instead we went with the alternative design, the hooks. This proved to be a very good decision as it allowed for us to fail and redesign something on our project multiple times. This is an important thing to learn in the design process. Not everything will work the first or even the second time you test it. It may take multiple re-designs to get it right. The hooks were re-designed six times total and the final product came out to be a combination of them all.
Brakes: The idea for the brakes came about in the brainstorming session. We wanted our dolly to be unique from most other dollies and so we came up with a few ideas to set our design apart from the others. One of those ideas was to put brakes on the dolly to stop it on slopes. We figured that our target market was those who are short of strength and if they have a driveway that is steep, especially in winter, a heavy trash bin on a heavy dolly would go down that at a relatively fast rate and the operator would not be able to stop it, without a brake that is. So we put a brake on our dolly and the addition proved to help our design by making it safer. The design for the system itself was inspired from other systems of similar design. Our design was simply improvised and based off of those other, most common designs.
Extended Scoop: The need for the extended scoop came about when we realized that the leverage created by a normal scoop for a dolly was not enough to fit the needs of the average residential trash bin. We simply needed a longer scoop to create the necessary leverage to lift the trash bin. We extended the scoop from around six inches long and a foot and a half wide to sixteen inches long and two feet wide. This made the bottom very heavy as the steel plate that was added was a quarter inch thick. To counter balance this we added a plain steel plate to the top of the frame to weigh it down so that it could go into sitting position without being pulled back into standing position by the weight of the new scoop. This new scoop allowed our dolly to pick up and hold a trash can with as few problems as possible. Though it created other problems that had to be fixed, the important thing was that it fixed the biggest problem of not being able to pick up a trash bin at all.
Other Miscellaneous Parts: There were many other parts that had to be designed and built or bought for the dolly 2.0. However most of them are not unique to the dolly 2.0. Most of the parts comprise of nuts, bolts, and the original frame of a standard dolly. These parts were not included individually in the prototype design description because we as a group felt that it was not necessary to include parts that we did not design and build ourselves.
Cost of prototype: There are many different materials and parts to take into account in the prototype design of the dolly 2.0. Those materials include a dolly frame, a brake lever, 12 feet of brake lines, 4 feet of rope, barbecue wheels and axle, multiple sheets of ¼ inch steel plating (no exact amount available due to weld cuts), bicycle brake pads, two ½ inch springs, 10 feet of 1/2 inch EMT steel bar, and 20 nut and bolt pairs of varying length and size. With all of the materials and tools used to build the prototype, the total cost was roughly $130. We did not pay that price because of donations and parts that we already had, but that is the total cost of the parts. We paid around $80 in total. This fit within our target cost for the dolly at the beginning of the project.
Projected cost of actual build: To reduce the cost of the dolly 2.0 without also reducing its strength and ability to perform its intended task, it needs to be made of as few materials as possible. The axles, scoop, nuts and bolts all need to be made out of A-500 ERW Structural Carbon Steel (refer to Target Cost pg. 19). This is to ensure the strength of all of the main supporting parts. The rest of the parts such as the frame, brake lever, hooks, and bonus wheel system can all be made out of aluminum (type to be decided). This will reduce the weight of the dolly 2.0 considerably, allowing it to perform better as well as become cheaper. The overall cost of materials will total out to be 80-90 dollars.
We talked to a few experts in the areas of design and metallurgy during the design phases of our project. There were many people whom we talked to but there were two men who stood out as our main contacts who gave us most of our expert feedback.
John Titus (firstname.lastname@example.org)- Design Expert with more than 30 years’ experience in the field of testing and design. We contacted Mr. Titus mostly through email. We discussed our project with him up through to the end of the design phase of the project. He gave us feedback on our design and gave us information on better designing our project.
Ray Nelson- Metallurgy and Construction Expert with more than 35 years’ experience in construction and metal work design. We contacted Ray towards the end of our project, when we were in the process of actually building our prototype. He gave us feedback on improvements that could be made to the dolly, types and sizes of metal to use in the weld process, and how a final product could be made when the time came.
We attempted to contact many more agencies, companies, and individuals, however, all but these two men failed to send a return message or opted to not be involved in our project.
This is the process by which the dolly needs to be built from start to finish. The purpose of having this is so that any person who wishes to build the dolly 2.0 can do so with a set on instructions.
The frame needs to be built before any other component; otherwise the Dolly 2.0 will not be possible to assemble later. There are multiple places where the 10 foot pipe needs to be bent. Starting at one end, bend the EMT pipe at 63 in 90 degrees, from that end. Repeat process once more (considering the new bend the starting point for the next bend) and the end product would be a curve pipe while assuming the bottom half where the pipe is not bent.
This is where the scoop would be using the steel plate, cut at 19” x 9.25”. By using thin steel plates 18” x 1”, these would further support for the frame putting at 9.875”, 20.75”, 31.625”, and 37.75”. The scoop and the rest of the steel plates are then to be welded to the frame. The leftover EMT pipe will make the handle. Repeat step 1 but at a shorter length of 6 in. The next step in the process will be to create the support bars. These are each 1.5 feet long except for the bar connecting them which is 2.75 feet long. These are flat bars that will attach to the first part made (the long U shaped bar that was bent at the beginning of the process). Cut out three 1.5 feet long bars and a fourth 2.75 foot long bar. Flatten all four out. Once flattened, attach and weld the three shorter bars to the first, long bar that resembles a giant U. Attach the short bars at 3 feet from the base, 3.5 feet from the base, and 4 feet from the base. Attach and weld the fourth long flat bar to each of the three shorter flat bars starting with the one attached closest to the top of the large U bar.
In addition to the frame slits are made starting at 32 “and are .7” and 1.7”. These are where the hooks are to be attached and will make it possible for the dolly to be versatile and compatible with various trash bins. A total of 8 slits, 4 on each side with the beginning facing the horizontal, and the rest vertical. The hooks themselves will be created through the 3D printer out of ABS plastic, or high temperature plastic, to ensure strength of the prototype. The dimensions for the hooks are 3.9” x3.5” x.6 and the cuts that are needed to be made are at 1.7” high and at a R2.08 and 1” and at the top of R3.25.
The frame at this point is done for the most part except for the additional holes needed to insert the other components of the wheels, bonus wheels, and the brake system. These holes need to be drilled on both sides of the frame at 7.6 inches up from the base, and 2.9 feet up from the base. The wheels are to be placed on the outside of the frame with a steel axel of .6” x 18” going through it at 6.5” with the same diameter of the axel. The wheel dimensions are 10” x 4”. Part of this assembly is also the brake system, which requires an assembled brake similar to that of an average bicycle brake system. Only one brake handle is needed and is attached to the top and it should be facing forward, so that if you lose control of the Dolly you are able to brake quickly and with ease. The wires to connect the brake pads to the brake handle themselves are needed to be at least 55” to reach and have slack so that the entire system does not catch or get stuck on any part of the dolly. The wire is to be attached to the frame using wire connecting brackets of the according size attached at various set intervals on the frame of the dolly. The brake pads are attached through the truss support plates toward the bottom at 7” high by the brake lever which is premade and to be bought along with the other materials. It is made with EMT pipe that has a ¼ inch hole cut slightly off center to allow for single dimension rotation. It also has a hole at one end to allow it to be bolted and has a hair cotter pin to force the brake pad to rub into the wheels and slowly stop it.
To build and assemble the bonus wheels, you begin by first cutting out all of the necessary EMT bars. Begin with the 10 foot EMT bar and measure out two 9 inch sections, two 10 inch sections, two 18 inch sections, a 23 inch section, two 2 inch sections, and a 4 inch section. For the PVC spacers cut out an 8 inch section and two 1.5 inch sections. Cut the 4 inch section of the EMT laterally in half; making two 4 inch half pipes. Next you must drill all of the holes in the bars to be able to assemble them. Drill all the way through for all of the holes. All holes are to be drilled using a ¼ inch bit. Start with the two 9 inch bars and drill a hole at both ends of the bars; the holes are both .5 inches in from the ends of the bars. Next are the two 10 inch bars. Repeat the process for the previous bars on these bars. At one end of the bars (it does not matter which until it is time to assemble) drill a perpendicular hole .5 inches from the hole(s) just drilled. Next are the two 18 inch bars. Repeat the process of the 10 inch bars on these bars. Next is the 23 inch section. Drill holes on both sides that are 2.5 inches in from the ends. Drill holes perpendicular to the first holes and .5 inches inside of them. Next are the two inch sections. Flatten all of them out to start. Then repeat the process for the 9 inch bars on these bars. Finally drill holes at one end of both the 4 inch half pipes .5 inches in from that end.
Now that all of the parts are cut, drilled, and welded, the dolly can be fully assembled. Attach all of the bracket parts using the bolts and nuts. Attach the 18 inch bar to the frame using the holes at one end of the bars and the top holes in the frame. Next slide on the 1.5 inch PVC spacers on either ends of the 23 inch bar, the wheels on the inside of them, and the 8 inch PVC spacer in the middle. Next attach the 23 inch bar to both the 18 inch bars using the corresponding holes (which will line up and be self-explanatory). Next create the moving parts of the brackets, the folding bars. Attach the 4 inch half pipe to the 10 inch bar. Next attach the 9 inch bar to the 10 inch bar using the 2 inch flat bar as the connecting part. Repeat process for second folding bar. Attach 10 inch bar to the 18 inch bar closest to the wheel. Then attach the other end of the folding bar (the 9 inch bar
Figure 18-Final Assembly
end) to the lower hole on the frame. Repeat process for other side. Finally you attach the brake handle to the frame handle so the handle is backwards when pulling the dolly. Attach the brake assembly to the support trusses for the axle. Insert the wire to the brake handle and return spring in the brake assembly. The dolly is now complete.
In order to find if our design was functional and if it needed any improvements, we went through a phase of testing. Testing included having each of the team members test the prototype first, to ensure that it was safe for others to use. After we had made sure that the dolly was safe for others to use and operate, we commenced testing. We tested multiple age groups starting with the youngest, 18-25 year old. This was a control to see how a fit able bodied person could operate the dolly. If an elderly person or injured person could not operate the dolly with equal success as a fit able bodied person, the design would be considered a failure. After we had tested the young we tested the elderly. The test procedures and data are as follows.
Incremental Testing Summary
The testing plans for the Dolly 2.0 are separated into three sections: materials, components, and the full assembly. Preliminary testing will be the mechanical aspects of the materials, such as strength and durability of the materials the dolly is made out of.
In the final assembly, the entire dolly 2.0 will be made out of a high strength, rust resistant steel alloy (except of course the rubber tires). The prototype however is made out of regular high strength steel, EMT, and PVC piping. All of the materials combined in the prototype should resemble the strength of the final assembly and are therefore fit for accurate testing. Finding the actual strength each of these materials will require research of prior dog bone testing.
Each component will be tested separately from the main assembly to ensure functionality. Component testing consists of individual testing of each part, such as the ability of the brakes to operate and force a moving load to come to a stop. After each component is tested, they will be brought together for the full assembly testing. Full assembly testing comprises of how each component interacts with the others and how well the overall dolly is able to function according to the specifications.
Prototype Testing 2/12/14 2/26/14
Wheel Testing 2/12/14 2/12/14
Hook + Strap Functionality 2/13/14 2/13/14
Brake Testing 2/14/14 2/14/14
Durability Testing 2/19/14 2/21/14
Environment Testing 2/22/14 2/23/14
Safety Testing 2/23/14 2/24/14
Final Product Testing 3/03/14 3/05/14
The tests will provide positive data for the Dolly if it can assist someone in moving their trash bin without difficulty. The first component to be tested is the wheels; the wheels must hold a trash bin and its load, and be able to move smoothly over the terrain. It includes both the front and back wheels, meaning the bonus assembly must also work. The second component to be tested is the hooks, both hooks needs to be able to secure the trash bin, handle the stress/load of the materials in the bin, and be able to adjust easily between the three sizes set on the dolly 2.0. The third component to be tested is frame durability; the frame itself needs to show resilience against the large amounts of stress that it is expected to undergo while in use. The fourth component to be tested is the brake system; the brakes must be able to stop a standard 200 lb. fully loaded dolly. The fifth test is the durability of the full assembly, whether or not the entire system together is able to handle the various stresses that it is expected to go through. The environment testing is the sixth test to be held. The environment testing consists of testing the dolly in various standard terrains which the dolly should able to tread through such as asphalt, loose gravel, and dirt. The seventh test is safety, the dolly must be user friendly, with very little sharp edges, few mechanical hazards, and able to handle the load for the user without a system failure that could result in injury.
In order to perform most of the testing, the Dolly must be assembled completely or nearly so. At this point in time, the prototype should be being built so that it can be tested and reflect accurately on the design. Some of the components on the dolly must be separated from the dolly in order to complete testing of those components. All the full assembly testing will require trash bins of various sizes, to ensure that as a whole, the dolly is of universal size for the many different trash cans employed by different cities. The dolly needs to be tested on different terrains, such as grass, mud, ice, gravel, and cement. For the actual data and results of the testing, each test will include a survey for users to provide feedback and their current place of residency to ensure that the testing was done in many different places, with many different trash bins.
Some of these materials are needed as a precautionary measure to be used in the event of a component failing or other reason and needing replacement for further testing.
- 10 ft. EMT Pipe
- 9.875”, 20.75”, and 31.625”, 37.75” Steel Plates
- ¼ in. diameter by 23 in. length Steel Axle
- 15 in. PVC Pipe
- (2) 5 or 8 in. Diameter Wheels
- (2) 10 in. Diameter Wheels
- (8) 5/16 by 3 in., and (10) 5/16 by 1.5 in. Bolts and Nuts
- Brake parts: Brake Handle (standard size), 53 in. of
- (2) 1 in. Hair Cotter Pins
- (3) Trash Bins-120 gallon, 150 gallon, 180 gallon
- Camera capable of video and image recording
Each component of the assembly has specific criteria it must meet for testing. The frame must be universal and have the ability to accommodate any size, for any kind of trash bin, and must have the durability to last for at least the average life cycle of a regular dolly (13-18 years on average). The hooks must be able to grab and release any kind of trash bin. The wheels must be as durable as the frame for the most part, easy to change, and capable of holding the average maximum trash bin weight (200 lb. weight limit standard for city dump vehicles). The bonus wheels must be as durable, if not more, than the other set of wheels, easy to replace, and also capable of holding the average maximum trash bin weight. The brakes must be not wear out too quickly and also must be able to stop a runaway dolly. The scoop attached to the frame must not bend under the maximum weight for a trash bin as previously stated. The hooks must be able to hold the trash bin in place and release it when necessary. The straps are an additional precaution if the hooks are not able to properly attach to the bin, and for additional support.
The Assembly must fulfill design requirements: Be able to assist the user to bring their trash can with little to no difficulty.
- The wheels should be attached to the frame for testing including the bonus wheel assembly. Each wheel is filled with the appropriate air pressure of 22 psi for the large ones and 17 psi for the smaller bonus wheels.
- Apply the maximum weight to the bonus assembly (200 lbs.). This component of the dolly should move forward and backward with ease and no weight may be applied on the bigger wheels at this time. When the bonus wheels are folded out, the angle it should be to support the frame is approximately 45 degrees from the ground.
- All the wheels should carry a total of 200 lbs. bigger wheels of 200lbs. and smaller wheels of 200 lbs. The testing will consists of putting weights of various sizes on the dolly and moving them at least 50 feet without failure or increased difficulty.
1. The hooks and the strap should be attached to the frame, the strap below the slots for the hooks but above the place for the bracket attachment. Each hook must be able to turn at a 90 degree angle in the horizontal direction facing the scoop and moving up and down to each slot with ease. The strap should adjust to any size trash bin for additional support or in cases where the hooks cannot be used. The entire strap should be a minimize length of 5 feet and maximum of 7 feet.
2. The test for both the hooks and the strap will be moving various sized trash bins that are fully loaded and attached to the full assembly by either the hooks, straps, or both.
- The brake parts should be attached to the frame with the pads touching the front wheels when the brake is pulled. The wiring from the handle to the pads is at least 55in., depending on the amount of adjustment slack attached to the system.
- The testing will require the maximum weight with the largest trash bin. The brakes must be able to stop the fully loaded trash bin in motion with ease.
1. This testing requires the entire assembly, where it is under extreme pressures for data results of its strength and resilience. Pressure points will be on the bonus assembly including the brakes, hooks and the slits, and the frame as a whole. Applying pressure to the weakest parts of the bracket is essential to ensuring the strength and durability of the dolly 2.0.
- The testing will require various weights and trash bins with movement. Terrains will be grass, mud, gravel, rocky, snow, and ice. The dolly must be taken over these terrains without much difficulty or need to adjust the dolly in any way.
Final Product Testing
1. This testing will be all the testing at once to make further improvements and if necessary redesign components.
Because of the target consumer group being elderly, injured, or disabled, safety is an especially high priority for all testing. The users of the dolly 2.0 will be responsible for various loads while they are using the product, the dolly must be able to hold these loads without fail to ensure that the main safety risk, that being the full load of the dolly falling, does not happen. The dolly must be able to function on many different terrains. If it were to fail on any terrain not considered to be extreme or not standard for trash bin use, (ex. 70 degree slope, field of lava, body of water, etc.) the product would be considered unsafe.
The device has very consistent results and performs quite simply. The initial limitations affected the results in that because of having a shorter leverage at the scoop, some testers had trouble leaning the bin back (this proved to be the only major problem with the device). Once placed in the pulled down position, the device performed flawlessly and succeeded in its designations in all tests thus far. The data that we have obtained points in a fairly successful direction and can be taken positively. It gives some feed back into what parts of the device still have need for modification.
Overall the testing was carried out through our design specifications and test procedures. From our results, we gather that the users were able to use the majority of the dolly’s functions without difficulty. They were able to set up the dolly position (bringing down the bonus wheels) and moving it without any weight every single time. The problems occur when they are testing the dolly with a heavy/maximum weight and are trying to pull the bonus wheels down. Most were able to secure the trash bin, but some could not pull it down, which means they could not move the bin at all in a real life situation. Initially the weight was being centered at the top instead at the bottom of the dolly due to our lack of functioning hooks and the use of simulated ones instead. We fixed part this problem by manufacturing functioning steel hooks to test and another part by adding a longer scoop. This did not fix the problem entirely though it helped. Even with the improvements it would require the user to put more stress than needed in the original design specifications, meaning that stress is being applied in areas that were not predicted in the original design. With the targeted audience as the elderly, disabled, and injured, it makes it difficult to have any incorrect weight distribution.
Initial design recommendations were the scoop and hooks. By extending the scoop, the weight at the bottom of the trash bin is more supported by the dolly. It would distribute the weight of the trash bin to the dolly and put the majority of the stress at the bottom, which makes it easier for the user to pull down the dolly into rolling position. The hooks that were designed work but cannot be properly tested due to our inability to afford to making because of cost and other factors. The hooks we had were only able to be tested without weight because of the strength of the plastic they are made out of. The current slits which the hooks are able move to adjust the height are in the incorrect positions as well. They are slightly off. The hooks were not able to grab the trash bin from their position, but this was partly due to their design as well. Further modification has enabled the hooks to properly grab the trash bin. It needs to be made out of metal to give it more strength and prolong their use. While making these improved hooks, modifications are to be made so that they can fulfill the design specifications requirements. The test results with the new steel hooks indicate that they are successful in their purpose.
As a whole the data collected shows need for a few more improvements. One such improvement is a step lever bar at the base of the dolly which a person would press their foot onto to get the dolly into moving position. Another improvement would be a metal brace in front of the dolly’s main wheels to stop them from coming in contact with the wheels of a trash bin. Another improvement would be the brake wire. Instead of having two wires connecting there should only be one wire so as to make it easier to adjust. Some of these improvements will be added to the dolly before final presentation. If they can be added with the time given then they will be added.
All of the testing data shows that the product design works and is successful overall but most likely is open to much improvement to the overall design so it is more efficient as a final product. The results imply that we are successful if one looks at the overall goal of the project. Our goal was to make it easier to move a trash bin from one point to another. Without fail, our device made this possible. The only difficulty came when moving the trash bin into a moving position. Seeing as this is a problem with trash bins already, we can confidently claim success in our goal. We may solve the other problem in the future by making changes in our design, but for now we are successful. The design solution performs as intended and is a partial solution to the problem. With the improvements it will be a full solution to the problem.
Most participant feedback is positive and does not include need for improvements. Most participants included in their personal feedback things like “works great” or “I like the design” or even “When can I get one?”. Some included a more detailed response. One response from an elderly woman, age 66, is as follows, “Scoop is not long enough. Thus it did not reach far enough under the garbage can to offer the support needed to pull the can back far enough with sufficient leverage.” Another response was from a man with an injured shoulder. His response is as follows, “Very nice. Had a hurt shoulder, very easy to lean back and prop up.” Most of the feedback and conversation with the test subjects indicated that our design was good but could use some improvements, which is to be expected as this was a prototype. Those who could not use the device fully stated that they would still consider purchasing the product if improvements were made to it that would allow them to do so. The necessary improvements to the design will be made before the final presentation.
One of the current failures is due to the scoop. It is not long enough which makes the leverage go down. This makes it very difficult to move the dolly into the moving position.
With the adjustments added with metal hooks and a bigger scoop, the dolly works better than it did before. The trash bin is now firmly secure, it fulfills the design specification. The main problem is still the weight distribution, the dolly is not counterbalancing the trash bins weight and it is making it hard to pull down. A solution we have to this is adding a step bar for the people to step on in addition to pulling back on the dolly.
Evaluation of Prototype
Throughout the testing process we found many good aspects about our design as well as a few bad things. The pros and cons of the device are as follows.
- Original Idea
- Functions as Intended
- Low Manufacturing Cost
- Visually Stimulating
- Easy to Use
- Assists Those Who Need It
- Solves Problem
Improvements and Recommendations
Though we did get the idea across for the Dolly 2.0 prototype, we still have many future plans for the innovation and many improvements to be made to the design.
One aspect about our design that we would like to improve upon is the bracket design. In our prototype the bars would slip in and out of position too easily and would not lock into place when in use. We would like to have brackets that have an automatic locking mechanism when the bars go in and out of use. One locking position for storage and one locking position for when the dolly is being used. This would solve the problem of the wheels coming out when the dolly is not being used and the opposite problem of the wheels not staying out when the dolly is being used.
Another improvement that could be made is the wheels on the bonus wheel system. On the prototype they are made out of barbeque wheels and these do not allow for much freedom of motion. Though it would add to the cost of the design, we would have liked to have had wheels that go in multiple directions, or Omni wheels. These wheels would give the dolly a much larger range of motion and would allow a user to move the dolly around objects much easier. These wheels are expsive and could not be used on the prototype.
Another improvement that we would like to make to the dolly is the brake system. The brake system on the prototype was thrown together based off of the parts we had available. We would like to have a brake system that is specifically designed for and around the wheels of the main axle and wheels. This would improve the effectiveness of the brake system by increasing the contact between the pads, and the rim of the wheels. It would also make the brake system more compact and adjustable like that of a bicycle. Along with being better fitted to the dolly, we would like to move the wires for the brakes onto the frame of the dolly, so they would not be hanging loose and have more of an opportunity to become unusable. This would make the system enclosed and allow for the dolly to become more compact.
Finally, we should like to make the entire system more compact. The current system is too bulky for easy storage and would be difficult to transport anywhere. Some improvements that could be made to make the system smaller include putting the scoop on hinges, adjusting and customizing the sized of the wheels, and changing the length of the bars on the bonus wheels system.
Putting the scoop on hinges would solve most of the compact-ability problem. With its 16 inch length, it currently takes up too much space. The hinge would allow the scoop to fold up towards the dolly and lock into place.
Changing the size of the wheels would allow for the design to become further compact. Making the wheels as small as possible would be best for this design. They would take up less space and allow for easier storage. Along with changing the size of the wheels, the size of the bars that attach them to the frame must be changed as well. The length of the bars depends on two variables: the weight distribution of the dolly and the size of the wheels.For the final build of the dolly it will be made out of more aluminum than anything else. This will make it lighter and change the center of mass. The change in the size of the wheels coupled with this would change the length of the bars that attach the wheels. They would most likely become longer. The higher up the dolly is able to sit, the easier it is for an operator to use and having longer bars creates a higher operating position.
As this project came to a point of culmination, we find that we learned far more than we expected to this year. The process of designing and building something complicated, and doing it properly, is a tedious one. Sections of our project that we thought would take only two weeks to finish ended up taking up the time of just over a month. Not everything that one would expect to work on an invention works. We found these things out by experiencing them first hand in our project. There were many more things that we learned about the process and other things as well and all this knowledge will be useful to us in the future. This project was both frustrating and fulfilling at the same time. Though we struggled at times, we believe that overall it was worth the time taken to complete it.