The Hanger.docx

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The Hangler Dangler

Fixing Backpack Stability

Team 163:

Eric Poynter

Bryce Barringer

Thomas Janssen

Jake Working

May 16, 2014

Client: Rose-Hulman Graduate

Course: EM103 Introduction to Design

Advisor: Professor Sean Moseley

Executive Summary

The Ogio Epic 108090 is a mainstay among freshmen and sophomores that attend Rose-Hulman Institute of Technology. This backpack was chosen by the IAIT staff at Rose-Hulman and comes with the laptop bundle that all incoming freshman are supposed to buy. So, naturally, when students cannot make their own decision concerning a major part of their college experience (such as a backpack), they will have complaints surrounding said backpack. The Ogio Epic is an example of this and users have identified a main problem being the stability of the backpack and how well they are placed during class time.

A design was implemented, shown in Figure 1, which will solve both stability and organizational problems. Our product is designed to hang the backpacks up on the tables and out of the way. The large rotating head is equipped with a rubber bottom that inhibits sliding. The head is fully customizable as customers can choose a design featured on the top and the rotating feature makes it very portable. The hook then sets around the table’s edge and keeps the backpack balanced and stable.

The proposed idea is made out of low carbon steel and neoprene rubber. With the mathematical models, the factory of safety is 115. The carbon footprint is reduced by using recycled material.

Figure 1: The Hangler Dangler

Table of contents

The design problem

Scope of Work4

Background4

Prior Art5

Criteria6

The proposed solution

Summary8

Detailed description8

How well the design is expected to work

Criteria-based test results10

Strengths and weaknesses11

Next steps11

Works Cited12

Supporting evidence

User-needs research13

Alternative design concepts14

Materials selection16

Performance modeling17

Eco-audit18

The Design Problem

Scope of Work

For the last two years, incoming freshman students at Rose-Hulman Institute of Technology have been required to buy the Ogio Epic 108090 backpack as shown in Figure 2. This backpack has been chosen by the Institute for its advanced laptop carrying technology and multiple pockets for anything and everything an engineering student could carry. Yet, even with all of its desirable features, the backpack still lacks in many areas.

The problem our team is focused on is classroom organization alongside with keeping the backpack upright for ease of use. We came to this conclusion upon obtaining information from fellow students, freshman, and sophomores who were dissatisfied with the stability of the backpack. During class, stability issues led to organization problems as the backpacks would continually fall over and become a hazard. This, in turn, would affect the professors as students have witnessed multiple professors trip and come close to falling while just walking around desks.

Figure 2. The Ogio Epic 108090

Background

Backpack stability and organization may not be the first thing that comes to mind when deciding how to improve a backpack as an aftermarket attachment, but it was a major issue that repeatedly came up among our stakeholders. The stakeholders in this project are the main reason for our focus of stability in this project. We identified primary and secondary stakeholders that would be affected.

The primary, and obvious, stakeholders are Rose-Hulman freshman, sophomores, and faculty who currently have the Ogio Epic 108090. They would be the consumers for our product and their input is the most important for the design and functionality of our final product. If our potential consumers do not desire to purchase our product, this would become an issue in that our company would not make any profit and neither would the Rose-Hulman alumni who is funding the project.

Along the same lines as current students as stakeholders are the future students at Rose-Hulman. The next two waves of students will have to purchase the same Ogio Epic 108090 backpack. They cannot be interviewed for the product design but their opinions are presumed to be similar to current students.

Secondary stakeholders were chosen as those who would not directly buy the final product, yet still be affected. IAIT, the manufacturer, the company whom we buy our materials from, and the graduate funding the business were classified in this category and their opinions are still considered during the design process.

IAIT has a more technical stake in keeping the product safe for use at Rose-Hulman. The staff at IAIT has seen all sorts of mechanical errors as well as internal problems from students’ laptops. A product designed to elevate the backpack off the ground must not fail and cause damage to the contents of the backpack or the laptop. This would just create unnecessary problems concerning laptop damage for IAIT to deal with.

Students and faculty at Rose-Hulman with their mindful approach to recycling and sustainability would be more inclined to purchase a product that was made of recycled materials, recyclable itself, or even manufactured at a green factory. This poses structural limitations on what materials can be used to create our product.

Along with structural limitations, incorporating these green standards would also cost more. Green designs usually require more attention to detail which could potentially reduce the amount of automated manufacturing [2]. This attention to detail, however, would create a more environmentally friendly product.

Prior Art

Inspiration for our product came from current purse hangers. These purse hangers came in two distinct designs, one more portable than the other.

Figure 3. Collapsible Design

Figure 4. Rigid Design

Figures 3 and 4 show two purse hangers available to buy currently online. Both feature a rotating head for better portability when not in use and a custom design on that head. The difference is that the collapsible design is, in fact, collapsible. The part of the system that holds the purse can be wrapped around the head for maximum portability as compared to the rigid design that cannot be retracted.

Prices for these designs range anywhere from $7.95 to $13.95 for the collapsible hanger and $9.99 to $12.99 for the rigid hanger [1]. Some of the hangers available have a way to customize the head to a design that the consumer wants. All of these options were taken into consideration and inspired our own product.

Criteria

After identifying the specific problem of stability combined with classroom organization, our team set out to develop specific criteria in order to expand upon what design we could create.

All criteria was generated through the triple bottom line, which connects the economy, society, and environment as shown in Figure 5. Certain criteria only meet one part of the triple bottom line while others connect to two or all three. Yet once all of them have been combined into a final product, their individual strengths will complete the prototype.

Figure 5. The Triple Bottom Line

The chart below (Table 1) describes the seven criteria chosen to create a product that will accomplish the task of organizing classrooms and keeping the Ogio Epic 108090 upright. Cost, strength, size, portability, visual appeal, damage by failure, and environmental credentials are the criteria we decided upon to define our product.

Table 1. Criteria for Stability/Organization

Criterion

Requirement

Cost

The cost must be competitive with the prices listed in the “Prior Art” section, while less than $20.

Strength

Can hold any reasonable weight of a backpack. Reasonable meaning 50 lbs or less.

Size

No larger than the dimensions of competitive purse hangers. Able to allow hanging from any table.

Portability

Able to fit into any small side pocket on the Ogio Epic 108090 with little effort.

Visual Appeal

Majority of users surveyed “like” the design and ability to customize the head.

Damage by Failure

Causes no damage to laptop or other contents of backpack from same height the backpack would be hanging if it were to fall.

Environmental Credentials

Recyclable and useable for duration of college career to life.

Proposed solution

Summary

The Hangler Dangler (Figure 6) is designed to keep rooms organized and uncluttered by keeping the backpacks off the ground. Our hanger can do this by using a rubber head that rest on top of the table while an attached bent bar hangs around the edge of the table and goes underneath the table. The weight of the backpack rests directly underneath the rubber head to prevent the hanger from sliding off the table.

Figure 6. The Hangler Dangler

Detailed Description

We have found through observation and personal interviews that one of the biggest problems of the Ogio Epic 108090 backpack is the fact that it does not stay standing up when left unattended. This problem makes problems for the stakeholders.

First of all the unstable state the Ogio Epic is in right now makes it dangerous for the laptops. This creates a problem for IAIT. As the backpacks continue to fall down, it creates wear and tear on the laptop which can lead to hard drive failures as well as other breaks. This makes a problem for IAIT. Our design keeps the backpack much more stable, which protects the laptop. This will save IAIT time and money.

The next group of stakeholders are the students and teachers. They complain about the fact that backpacks our strewn across the floor. Not only does this give the campus a bad look, it proposes a dangerous tripping hazard for anyone walking through a classroom. Our design keeps the backpacks up off the floor by hanging them from a table.

Our solution also fixes another problem that students have. It can been inconvenient for students at times to get things out of the backpacks. By hanging the backpacks from the table it makes it always easy to get the things the students need to get out of their bag. This saves the students time and frustration.

Another area we focused on is the environmental and economic side of our product. Not only does our product add convenience for the users, we have also concluded that our product is environmentally friendly and very economical.

Our product is made from carbon steel and rubber. These materials have low carbon footprints, which means our product will have a low impact on the environment. Not only does our product have a low carbon footprint, it protects our laptops and bags. This means we don’t have to replace as many laptop parts or backpacks. This also makes our product economical because students and IAIT won’t have to pay for replacements.

Figure 7. Top view of the table hanger.

Figure 8. Profile view of the table hanger.

How Well the Design is expected to Work

In the development of the product there were certain criteria that were needed to be met. These were or will be analyzed through mathematical computations/models, environmental impact using CES EduPack, user preferences, and future tests with an actual prototype. Strengths and weaknesses are also discussed with future plans for the product.

Criteria-Based Test Results

Cost. Since our product is meant for the students of Rose-Hulman, we decided that it should be relatively cheap to purchase. It is not a required item to have and to get more appeal from consumers, a smaller price tag is ideal. Knowing that we wanted our product to be inexpensive, we molded other criteria around it i.e. strength, size, and environmental footprint.

Strength. When researching other similar concepts, we found the most durable to be made out of metal. Knowing this, we went to EduPack and found what material that had a high modulus of elasticity, while still being cheap and easy to work with. We found that low carbon steel was the best choice. Using different mathematical computations/models, we were able to find the correct dimensions to be used for different parts, and still keeping the product as compact as possible.

Size. Nobody wants something that is large and is awkward to carry it around so that they can place their backpacks in an organized manner during class. This would not only be a burden, but create more clutter in the classrooms. Knowing this, we wanted something smaller in size, preferably something that could be put in a pocket of the backpack, without adding substantial weight. By using our calculations for strength, we were able to design something that is able to be held in just one hand with relative ease.

Portability. We decided that our product should be able to be carried within a pocket of the backpack, without cramming or adding a substantial amount of weight. We designed the product to be made from two pieces, the top round half and the hook that holds the backpack. These two pieces are threaded together by having threads on one end of the hook and a threaded hole on the side of the top portion. They are able to be taken apart for easier storage and can be fairly flat when placed on top of one another, making it able to slide right into one of the small storage pockets.

Visual Appeal. Every student that attends Rose-Hulman feels that they are unique and not like everybody else, and we wanted to incorporate that feeling into our product. Our consumers could have the options to get a custom engraving on the top portion with any text they would like, to having the school logo in high gloss acrylic paint on the top. The possibilities are very broad because the top presents a canvas for the students to be creative in personalizing their own product, while still maintaining the sole purpose of backpack support.

Damage by Failure. In hindsight, our product is fixing the intended problem, but creates another large issue. If our product were to fail, it would cause a decent amount of damage from our speculation. The product is designed so that it will not fail unless misuse by a consumer. On the off chance that it were to fail due to factors we have not foreseen, then the users backpack may take a small fall to the ground. Even though the fall is not substantial, many backpacks contain precious items such as laptops, phones, tablets, and miscellaneous items. These items are easily broken if dropped from only small distance, and this could create a potential problem for users. This is why we planned ahead and gave the product a low chance of failure by using durable materials to hold up and also prevent slipping off the table.

Environmental Credentials. With green factors in mind, we decided that our design should last a long period of time and not wear out, while still being recyclable. We needed something strong and decided to go with a common grade of steel, low carbon steel, because it is strong and able to be recycled to many other uses. This is a good thing because a vast majority of the product is to be made from steel so it has a lifespan that will outlast most consumer’s backpacks. The steel is also a much better option than plastic because it recyclable, strong, and has a much longer lifespan.

Strengths and Weaknesses

As we were designing our product we decided that we should fulfill each of our criteria as best as possible. We also wanted to make our product more durable than any other similar product on the market. We were able to fulfill these goals by using a very sturdy material and changing the design from many similar products. We also simplified the design so that it is easy to manufacture, while not losing any of its other characteristics. Our design is sturdier than other similar products on the market and can be used to hang more than one small item, it can be used for something large, like an average college students’ backpack.

One very large downside to our design is the overall weight and length of the hook. Since the hook has to hold up to a large amount of stress, it is fairly heavy duty and requires a decent amount of material compared to other similar products. The whole weight of the product is a little over four pounds and that can be quite a bit over time. The backpack alone weighs this much by itself, from just the material. This means to have the backpack with the hangar in it, is well over eight pounds to carry.

Overall the product does more good than harm because it may weigh more than a student would prefer, but it solves the problem at hand and is very durable.

Next Steps

For our next steps we would like to do some real life testing with prototypes. This would be able to give us conclusive results on our estimations and prior research. By having full testing, we could give an estimated life span and find out how much weight the product could actually hold safely, since we do not have enough knowledge to currently have accurate mathematical models. By finding the final details out we would be able to market the design to Rose-Hulman students.

Following the extended testing, we would also like to do some market research by having participants use our product for an extended amount of time and report to us how they feel about it overall. By having this information we would be able to market it toward the students better, and make adjustments to our product by having the feedback. This would create a much better selling point and our client will benefit from the extra testing.

Works Cited

[1] “Floral Pattern Purse Hanger - ** Various Designs **." Amazon.com: Blue Floral Purse Hanger (Blue/Silver): Clothing. Web. 14 May 2014.

[2] “From the Forums: Why Do "Green" Products Cost so Much?" TreeHugger. Web. 14 May 2014.

Supporting Evidence

User-needs research

To determine the different problems that students and faculty were having with the Ogio Epic 108090 backpack, we went around various floors to ask students about their opinions concerning the backpack. While we did not document the exact number of students, we recorded all of the various concerns that they were having with their backpack. These students included both those who used the backpack as well as those who use a different backpack of their own choosing.

The main concerns that the students brought to us were the following: laptop venting/safety, no clips to attack things to on outside, back pain due to heavy loaded backpacks, they sit unsafely on the floor during class, zippers break easily, cup holder is too small, phone pouch is not practical for modern phones, and expressed concerns about weather proofing. After compiling these concerns with each other, our team focused mainly on the concerns that could be solved without actually problems into six different ones relating to the overall problems of structure and convenience that the backpack lacks. From these, we then decided to focus entirely on the fixing the stability of thy modifying any original part of the backpack. With this in mind, we narrowed down the various backpack so that we might design an attachment to help keep the backpack in an orderly manner during classes. By doing so, it would prevent the backpack from falling over so that the potential for someone to trip over it and damage the contents such as the user’s required laptop would be greatly reduced.

Alternative Design Concepts

Concept Selection

From an original list of 100 varying designs, we narrowed down our ideas into four main designs. We first cleared off the impractical designs that helped lead us to the more practical ones, and of these we set some criteria to help decide the final four. The criteria we considered was the actual size of the object, how portable it would be so that students would not be even more burdened with the design, how much damage the design would potentially prevent and how reliably it would do so, as well as the cost of the design considering our $60 given budget. With these in mind, we finalized our main designs to 1) be a ridged T-like structure, 2) a set of collapsible bars that the backpack would rest on, 3) a divider that would be inserted into the backpack to help localize the center of gravity, and 4) a hanger that could be set on any table from which the backpack could hang. After presenting our designs, our instructor made the ultimate decision for our group to make the table hanger for our design.

Alternative Design Concepts

Bar Clamps The first alternative design (Figure 10) that we considered focused on supporting the base of the backpack. The way it is designed to work is that the bars would be able to collapse in and expand out so it could conform to the current size of the backpack and keep the contents close together. This would help center the weight as well as give the backpack a rigid bottom that would greatly reduce the chances of the backpack falling over on its own. The ends of the clamps are shaped in a triangular manner so that there would be more support on either side if the backpack started leaning, and the height of the ends would prevent it from tipping out of the base.

With the triangular ends of the bars, they will not conveniently fit in the backpack with the books, making this an inconvenience for students to carry around with them. A great aspect of this design is that while it is portable, it could also be left in all of the classrooms and just provide the students with a convenient location to place their backpacks throughout the day and both students and professors wouldn’t have to worry about tripping over backpacks in the middle of the isles. A downside to this design though is that it is rather large and bulky in comparison to our other designs.

Figure 10. The Bar Clamps

The T-Support Another alternative design that we considered was the T-stand (Figure 11) that would let the backpack remain on the ground but would support it from the straps rather than the base. The name of this design comes from the general “T” shape that it has, and the stand sets rigid on the ground with the backpack hanging from it by the straps. The three legged base keeps the stand stationary when holding the backpack, centers the weight, and is capable of supporting loads heavier than a typical backpack’s weight. However, a key fault is the rigidity of the frame. Being rather bulky, there is no convenient way to transport and store the stand outside of class. The benefit of this is that it is compatible with any backpack of any size and unless used wrongly, the stand will not fall over on itself while in use.

Figure 11. The T-stand

Divider Insert Our third alternative design is a metal or hard plastic insert (Figure 12) that would divide the backpack into two sections causing the books to lean in towards the middle thus centering the weight. Our focus with this design was to look away from external attachments and look to supporting the backpack from the inside out. The great thing about this design is that unlike the bar clamps and T-stand, it sets inside the backpack and never has to be taken out, making transport of this design the most convenient. The thin wall in the middle would take up very little internal space and would allow for books to lean against it from either side to center their weight. The lips on either side of the base help prevent the books from falling flat and gives more support to the books if it is not a full load. The rectangular base creates a flat bottom that makes the backpack sturdier while resting on the ground.

While being the most convenient to transport, it is the most inconvenient to detach from the backpack once inside. With books on top of it, and the rigid frame of the design itself, the divider is very difficult to insert and remove. However, once inside the backpack, it has been designed to not take up too much space and to remain in the backpack all the time. Moreover, the lips on the ends of the base should prevent anything from getting stuck underneath so there should be no reason for the insert to be removed once in place.

Figure 12. The Divider Insert

Design Description

Materials Selection

We decided to use low carbon steel for the majority of the product. We chose this because of the high modulus of elasticity and low carbon footprint. Using EduPack, we found that low carbon steel was the ideal material because it was the only material to be pliable and have a decently small carbon footprint. We also decided to use neoprene rubber for the bottom side of the disk that sits on the table because it is renowned for the gripping qualities and we felt that it would keep the hook in place the best.

Figure 9. Carbon footprint versus Young’s Modulus for material selection.

Performance Modeling

We chose a weight of 80 lbs so that the hanger would have no problem supporting any backpack that someone might place on it with the assumption that the average backpack weight is somewhere between 20 and 30 lbs for the average Rose student and professor. The radius that we chose for the design was 0.25 inches and we made the whole design out of low carbon steel. Taking the average of the material’s yield strength/elastic limit, we got the numerator of the FOS to be amount 46.8 ksi and sigma to be 407.4 psi giving a FOS of 115. While this seems to be an excessively high factor of safety, we have not been able to test our product and this is using what we found to be the appropriate material of choice. With this factor of safety, we are very confident that this will not fail at any potential backpack weight within reason.

Eco-Audit

Using the EduPack software we were able to analyze the environmental impact of the table hangar. We used fifty percent recycled low carbon steel for the material and polyvinylchloride for the neoprene rubber because EduPack did not have a much closer equivalent. We also used recycling as the method of disposal for the product because it is nearly all recyclable. Table 2 and Figures 13 and 14 explain the results numerically.

Table 2. Eco-Audit of the Hangler Dangler.

Figure 13. Energy expenditure from the Eco-Audit.

Figure 14. Carbon footprint the Hangler Dangler will create from Eco-Audit.

In designing how the product were to be made, we decided it would be best to find materials that are easily disposed of, like steel able to be reused and used for a different purpose. Using recycled materials in creation of the product, it also lowered the carbon footprint overall because it did not have to be raw material found in nature; it could easily be reclaimed / recycled. The final design solves the issue or backpacks falling over and does it all in one small convenient, and environmentally friendly device.