Schryer: The Full Shoe ExperienceTM

by Dan Koenig, Shane Kiger, Sam Boland, and Pragya Singh

EDSGN 100HPenn State

March 20, 2015

Executive Summary

The objective of this project was to create a unit that would effectively dry a pair of shoes while simultaneously freshening them. After significant research, several concept designs were generated using the 3-3-3 and Gallery Methods. Taking into consideration practicality and effectiveness, the concept selections were then narrowed down to three final designs, which were then compiled into a concept scoring matrix. The scoring matrix determined the design concept that most effectively facilitates airflow, is easy to manufacture, and is convenient to use. The design not only dries shoes efficiently and effectively, but also also normalizes odors to a pleasant scent. This design will hopefully become an appliance that most households will have in order to maintain shoe quality, as well as to save time.

Introduction

The project’s main purpose was to utilize the airflow provided by a motor, which carried a certain number of constraints and limitations to the design. One usage of the motor’s airflow is drying, which led the design team to select the idea of a shoe dryer, or “Schryer”. The objective of the shoe dryer is to significantly cut down on the drying time, as well as normalize odors caused by bacterial growth, which will ultimately maximize the durability of shoes.The design team recognized that in order to dry the shoes as quickly as possible, airflow needs to be maximized into the direction of the shoes’ opening. In addition, the unit needed to be designed in a way that is convenient to use.

Research

Before concept generation can begin, preliminary research must be conducted in order to properly understand the task at hand. The motor was measured and wind speed was calculated to determine the limitations of the dryer. Online sources were also consulted to gain further knowledge of similar shoe drying products in the market.

Motor Characterization

The varying watt usage, wind speeds, and drum speeds at each of the three settings are presented in Table 1.

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Table 1: Specific measurement of wattage, wind speed, and drum speed at each of the motor’s three settings.

Image 1: Motor of an air conditioning unit that will provide airflow for the dryer

Customer Needs

In order to determine customer needs and their correlating specifications, online research was conducted by consulting shoe dryers that are currently available on the market. There are a number of target specifications that need to be reached for maximum customer satisfaction. These range from drying in a timely manner to being able to fit larger pairs of shoes. A list of these customer needs were compiled into Table 2 and consulted for ideas during concept generation.

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Table 2: Compilation of target customer needs and their correlating design specifications.

Concept Generation

Realizing the Problem

Before the first step of concept generation, it is essential to determine the important factors that will ultimately shape the design. In order to create a more realistic scenario, the team created a “person” for whom they were designing a shoe dryer and freshener. Take a caddy who just went two loops in the pouring rain because crazy members are not afraid to play in any condition. The caddy walks in his front door and he hears his sneakers squeaking and sees it leaving a water trail with his every step. Currently, he has to stuff newspaper into his shoes. This does a half-decent job at drying the shoes but it fails to reach every surface of the shoe. Also, after ten hours of working, his shoes have quite the unpleasant stench. The newspaper causes the shoes to retain this horrific smell while drying. This caddy needs a new and viable option. The concepts that were generated were based on this scenario as well as the customer needs mentioned in the previous section.

Generating Concepts

The team utilized the 6-3-5 Method which fit nicely for the group of four. The team used a modified 3-3-3 Method to jumpstart concept creation. Each person began by writing three ideas in the far left hand column of the three-folded paper. Then the paper was passed to the next member and then passed again until all three columns were full of ideas. Some of these ideas, shown below, became the possible designs in the concept scoring matrix.

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Image 3: The three columns of the 3-3-3 Method are shown in the image above. The sequential member

could either build upon the design of the previous member or generate a novel one.

Another concept generating tool the team used was the Gallery Method. Using the raw designs from the 3-3-3 Method, the team hung the pieces of paper on the Whiteboard. Using markers, each member further elaborated on the design from their individual sheet they deemed best. After ten minutes of drawing and describing at the board, each member presented their design to the group. The three designs that were voted to be most likely to succeed were chosen and were used in the concept scoring matrix.

Image 4: An overview of the Gallery Method used to generate concepts for a shoe dryer and freshener.

Each member was given a section of the board to demonstrate their ideas to his or her colleagues.

From the Gallery Method, the three best ideas were selected as preliminary concepts to be further tested.

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Preliminary Concepts

● Hook Dryer: This concept uses a very simplistic design to direct the airflow in a manner than most effectively enters the shoe openings. Shoes are suspended from hooks directly in front of the motor in order to facilitate the maximum amount of air into the shoes. The bottom base of this design slants upward to push the air out of a smaller opening. A flap with slits is positioned in the front to push air back into the unit and further minimize drying time. Some sort of freshening device is placed at the opening of the motor to normalize odors.

Image 5: The Hook Dryer concept employs a simplistic design that controls air flow directly into the opening of the hanging shoes.

● Shoe Incubator: This concept is focuses on dramatically increasing the number of shoes that can be dried at once within the unit. By essentially creating “drawers” that will be pulled out for the shoes to be placed in, the dryer can be expanded in length to fit multiple pairs at once. A vent will be present at the end to allow air to exit the apparatus. A freshener pack is placed near the front of the motor opening to eliminate bad odors.

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Image 6: The Shoe Incubator concept maximizes the number of shoes that can be simultaneously be dried and user comfort by utilizing “drawers.”

● Wind Tunnel: In this concept, a triangular block will be placed behind the heel of the shoe to allow the flowing air to optimally enter the shoe and effectively dry and freshen it. On the top of the unit, slits are placed to direct airflow out of the dryer.The concept ultimately failed because the motor would have to be placed on its side for the design to work. Placing the motor on its side drastically decreased its wind speed. This would have lengthened the time needed to properly dry the wet shoes.

Image 7: The Wind Tunnel concept uses a slanted platform in order to control airflow into the opening of the shoes, allowing air to circulate around.

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Concept Scoring

After finalizing three preliminary concepts to compare, a concept scoring matrix was utilized in order to decide on one final design to prototype and perform iterations on. This matrix is displayed below on Table 3.

User Friendliness (7.5)

Time/Airflow Facilitation (20)

# of shoes(10)

aesthetics(5)

manufacturability(7.5)

total

Hook Dryer 2 4 2 4 3 147.5

Shoe Incubator

3 2 5 3 2 142.5

Wind Tunnel

4 2 2 2 4 130

Table 3: The Concept Scoring Matrix used varying weights to determine which of the preliminary concepts most effectively achieves the objective.

Weights ranging from 1 to 20 were used for the concept scoring matrix and were determined by the specifications derived from customer needs, as well as by a marketing perspective. From there, the concept was scored on a scale of 1 to 5, with five meaning that the concept met the need the best and one meaning the concept did not meet the need well.

● Time/Air Flow Facilitation: This was considered the most important aspect of the design, since proper and effective airflow will maximize the drying time needed for the shoes. As such, it was assigned the highest weight of 20.

● Number of shoes: For a user of this product, the ability to fit multiple pairs of shoes is important, as it provides more convenience. It also sets the product apart from competitors, so it was given a weight of 10.

● User friendliness: The concept design needs to be simple enough that the user can use it easily. Being able to comfortably place shoes vs. hanging the shoes comes into play. This was assigned a weight of 7.5.

● Manufacturability: Ultimately, the design should be simple enough to manufacture in large amounts without taking too much time in the assembly process. A weight of 7.5 was deemed appropriate.

● Aesthetics: The dryer will be integrated within households, and should therefore have design that leans to the simple, clean side. This was not a very crucial aspect to the design however, and was given a weight of 5.

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Prototyping

In order to properly visualize the airflow and determine what aspects of design can be improved upon, prototypes were created and iterations were performed over them. Following the initial design of the Hook Dryer, the first prototype was created out of cardboard, tape, and wire. Three small slits of 1” by 5” were placed in the front flap of the prototype to facilitate escaping air. An anemometer was placed in front of the motor and in front of the slits, reading about 4 m/s and 8 m/s respectively.

Image 1: The first prototype follows the design aspects of the Hook Dryer as closely as possible.

The second prototype implemented larger slits to test the correlation between wind speed and slit size. The new slits were doubled to 2” by 5”. The anemometer now read 4.5 m/s near the motor and 7 m/s in front of the slits.

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Image 2: Prototype 2 utilizes larger slit sizes in order to increase wind speed coming out of the dryer.

Because the shoes are to be placed near the mouth of the motor, the design team recognized that it would be important to maximize the wind speed coming out at that position. Since the slit openings appeared to be increasing the wind speed dramatically, the design team decided to test if placing the slits in front of the motor before the shoes would more effectively dry the shoes. This iteration is displayed below in the third prototype. The new reading on the anemometer read 0.45 m/s, meaning this idea was ineffective.

Image 3: The third prototype has large slits placed in front of the motor, just before the shoes

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Calculations

Air flow measures the volume of air passing through the apparatus per unit of time. This will effectively contribute as a factor for how quickly something will dry in the machine.

Wind Speed (at opening) Conversion:20mph *(5280 ft/mi) *(1/3600 h/s) = 29.33 ft/s

Cross Sectional Area (of opening):10.5in*(11.5in) = 120.75 in^2= 0.839 ft^2

Air Flow = Cross Sectional Area x Wind Speed29.33 ft/s *(0.839 ft^2) = 24.6 ft^3/s

=1,476 ft^3/min (CFM)

The small scale test consisted of hanging wet rags on the hooks and running the blower for 5 minutes. The weight of the rags were measured while dry, and then immediately after getting wet. After five minutes in the device, the rags were removed and weighed again. To calculate the percent of water (by weight) removed from the rags, the weight of initial weight of water was first determined. This was done by subtracting the weight of the dry rag from the weight of the initially wetted rag. After the test was run, the rags were weighed again. The weight of the dry rags was again subtracted from this measurement to yield just the weight of water left in the rag. The weight of water before the test minus the weight of water after the test showed how much water had evaporated throughout the drying process. This calculation was then divided by the initial water weight and multiplied by 100 to achieve the percentage of water removed.

Rag 1: Water Weight = Wet Weight - Dry Weight0.284 - 0.106 = 0.178 lbs

Post Test Water Weight = Weight After 5 Mins - Dry Weight0.232 - 0.106 = 0.126 lbs

Water Evaporated = Water Weight - Post Test Water Weight0.178 - 0.126 = 0.052 lbs

Percent of Water Removed = (Water Evaporated/Water Weight) x 100(0.052/0.178) x 100 = 29.2%

Rag 2: Water Weight = Wet Weight - Dry Weight0.218 - 0.108 = 0.110 lbs

Post Test Water Weight = Weight After 5 Mins - Dry Weight0.184 - 0.108 = 0.076 lbs

Water Evaporated = Water Weight - Post Test Water Weight0.110 - 0.076 = 0.034 lbs

Percent of Water Removed = (Water Evaporated/Water Weight) x 100(0.034/0.110) x 100 = 30.9%

Table 4: Weights of Wet Rags After Being Hung in Schryer

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Dry Weight (lbs)

Wet Weight(lbs)

Weight After 5 Minutes in

Device (lbs)

Percentage of Water

Removed (%)

Rag 1 0.106 0.284 0.232 29.2

Rag 2 0.108 0.218 0.184 30.9

Table 4: This table illustrates the effectiveness of the dryer by comparing weights of 2 rags when dry, wet, and after being placed the the device for 5 minutes.

Final Design Description

After multiple iterations with the prototypes, the design of the Schryer was finalized. Unlike the prototypes, the full scale model of the Schryer was constructed out of wood to provide a more robust structure to hold the shoes. Shown below are the dimensions of the front, side, and top views of the completed Schryer model.

The CAD drawing of the Schryer, showing the dimensions of the front, side, and top.

Looking at the side view, the wooden structure is 13 inches long on the top, with a front opening that is 12.25 inches long. The total height from the floor to the top of the

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structure is 17.25 inches. This is also the height of the rear opening. The openings on the front and back are both 10.5 inches wide, as are visible in the front drawing. The top view shows the location of the hooks. Each hook was 0.5 inches in diameter, 3 inches from the front opening, and 2 inches from the side of the box. Where the shoes hang, the air blows out from the fan at 20 miles per hour (8.94 m/s).

As is visible in the view below, the final wooden model includes stilts for support on the front end of the wooden structure. Unlike the cardboard prototypes, the wooden model was too heavy to support itself and would fall away from the fan if not supported better. The stilts were one inch thick and protruded 5 inches down towards the floor.

Isometric front-side view of the Schryer, highlighting the stilt supports.

Another modification from the third prototype to the final model is the inclusion of the Febreeze pack to freshen up the shoes. The Febreeze pack was not included in the previous prototypes because the design team only had one that could be permanently attached. Though not pictured in the figure below, the Febreeze pack is located directly in the center of the hooks, one inch from the opening to the fan.

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The front view of the Schryer.The Febreeze pack is visible in final model presented to class, but not in the CAD model.

There are also two additional modifications that are hidden by the blower. The first is the Command Strips that were intended to be used to temporarily adhere the wooden structure to the blower. The Command Strips lined the edges of the wooden structure, meeting in the top corners, and adhering the structure to the flanges of the blower. Due to the fact that the final model constructed by the group was not level, the Command Strips did not come into contact correctly with the blower, and were ineffective.

The final modification to the design was added shortly after the small-scale test using damp rags. During the test, the turbulent winds occasionally caused the rags to come in contact with the blades of the blower. This was something that could potentially cause damage to the shoes, so it needed to be remedied. The solution was to include a piece of screen material, 3 inches in height, glued to the opening on the blower end, 4.5 inches from the top of the box. This band protected the shoes from coming in contact with the blades of the blower during the full-scale test.

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The rear-side isometric view. Command Strips are located where the blower and wooden structure meet. The band of screen material is not included in the CAD model because it was not originally planned to be

a part of the device.

If the device was to go through another design iteration, there are four improvements that should be made. The first would be to use a latch mechanism to attach the wooden structure to the blower. This would be much more reliable than Command Strips, and would do a better job of adhering the structure to the blower. The next improvement would be to cover the whole opening on the blower end with screen, ensuring that the shoes are more protected and will never come in contact with the blower. The third and final improvement would be to place the hooks on a track so that they are able to move forwards and backwards in order to dry shoes of varying size. There is a lot of unused space in the Schreyer, so it would be easy to accommodate larger footwear, such as boots, if the hooks were able to slide back farther away from the blower. For a final modification, a tray could be placed under the blower opening to collect any water that drips from the shoes.

Conclusion

Though the design is by no means perfect, it accomplishes the goal of creating a shoe dryer rather well. An effective shoe dryer must satisfy 5 customer needs: drying time is less than 2 hours, a freshener cartridge is placed inside, allows room for 12 to 13 inch shoes, weighs less than 10 pounds, and has sleek and clean design.

With more advanced equipment and more time, the aesthetics of the design could definitely be improved by using a higher quality wood, and rounding the edges of the

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box. However, it is safe to say that the Schreyer still meets the “sleek and clean design” requirement because the angles are pleasing to the eye.

The final design of the Schreyer features a Febreeze cartridge near the opening on the blower side, in between the hooks, to meet the “shoe freshening” requirement.Because the opening near the blower, where the hooks are located, is 17.25 inches tall, the Schreyer can very easily fit shoes upwards of 12 inches long with ease. This satisfies the “accommodating all sizes” requirement.

Although a full scale, full time test could not be completed with a real wet pair of shoes due to time constraints, the data collected during the small scale test is enough to prove that the Schryer can dry a pair of shoes in under two hours. As can be seen in Table 4, after hanging in the Schryer for 5 minutes, almost a third of the moisture was removed. Although the material that shoes are made out of is likely more absorbent and would probably take longer to dry, the data from the small scale test is more than enough to prove that the drying process will be a short one, no matter the amount of moisture in the shoes.

The Schryer was constructed out of lightweight wood and weighed less than 10 pounds. However, with more time and money, the Schreyer could very easily be constructed out of a lightweight plastic to minimize weight.

Overall, the Schryer met all of the most important requirements, and performs its function well. With more time and money invested, the Schryer could very easily outperform its competition, and become a staple in the homes of Americans.

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References1. "Duct Velocity." Engineering Toolbox. Web. 18 Mar. 2015.

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