EGR160DesignReport

Card Table Cart

InterEGR 160: Intro to Engineering Design

Lab Section 312

Professor: John Murphy

Instructor: Bob Rowlands

Student Assistants: Ka Tse, Kara Novotny

Presentation Tuesday, May 6, 2014

Client: Verona Senior Center

Team Members:

Kevin Abou-Zeid

Anjali Begur

Joey Burke

Matty Caulfield

Nathan Dobratz

Kayla Edwards

Alex Gehrke

Joe Goossens

Max Kahn

Danny Lerner

Marc McGuire

Ryan Michuda

Natalie Mysak

Chloe Olson

Ellen Restyanszki

Zach Self

Susan Yang

Ben Zastrow

Table of Contents

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I. Executive SummaryII. Introduction

● Client Summary● Problem Statement● Background Information● Design Specifications

III. Preliminary Designs● Brainstorming● Small Group Designing● Design Evaluations

IV. Integrated Design● Integrating Preliminary Designs● Changes After Combining Preliminary Designs● Design Review● Design Matrices

V. Modifications for New Purpose● Explanation● Problem Statement● Design Specifications● Design Limitation Changes’ Effects on New Design

VI. Preliminary Final Design● Measurements (With explanations of modifications)

VII. Fabrication● Methods

○ Day 1○ Day 2○ Day 3○ Day 4 ○ Day 5

● Testing and Analysis● Data Interpretation

VIII. Final Prototype● Summary of Final Design● Materials and Costs● Design Limitations

IX. Conclusion● Problem● Final Design● What the Team Learned● Design Limitations

X. Future WorkXI. ReferencesXII. Appendix A: Assembly & Installation Guides

● Materials List and Instructions for Assembly

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● Materials List and Instructions for InstallationXIII. Appendix B: Dimension DrawingsXIV. Appendix C:Product Design Specifications

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I. Executive Summary

The Verona Senior Center had 33 heavy floor tiles that they needed to transport from an

indoor room to an outdoor storage room several times each week. The cart design met this

need, allowing for transportation of eight tiles per load. It was designed with two bars in the

middle to lean the tiles on and a heightened edge on the base to make sure they wouldn’t slip

off. However, near the end of the design process the client informed the team that the

transportation of tiles was no longer necessary. Instead, the cart will be used to move six plastic

card tables within the Verona Senior Center. This information required some changes to the

design. The team built a similar cart to the original design with several small modifications to

reduce weight. The final product is capable of holding all six card tables at a time for easy

transportation and storage.

II. Introduction

Client Summary

Our client is the Verona Senior Center located on 108 Paoli Street in Verona, WI. The

senior center hosts activities for the senior citizens of the City of Verona. Some examples of

these activities are ping pong, Wii bowling, yoga, card games, musical and variety

entertainment and more. The various activities require the center to be rearranged frequently to

accommodate such a variety of events. For this reason, Program Director Chris Nye

approached the team because he needed to fix the issue of inefficient transportation of the

center’s dance floor tiles to and from storage. Later, Director Mary Hanson requested that the

cart be built instead for transportation of card tables, not floor tiles.

Problem Statement

The Verona Senior Center (VSC) has 33 heavy floor tiles that need to be transported

from an indoor room to an outdoor storage shed. The tiles need to go through a narrow

doorway, over an uneven sidewalk, and turn a sharp corner to reach the storage area. Currently

the VSC has no efficient way of doing this, as they typically carry the tiles one by one. The team

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proposes to create a cart that will be able to load eight tiles per trip. It can be loaded and

pushed by one person in order to significantly decrease time required to transport the tiles.

Background Information

To see what current solutions are available to transport tiles, the team researched

several different cart designs. SICO, a company that makes dance floor tiles similar to the ones

at Verona Senior Center, has two designs of dance floor caddies included on their website. One

design has the tiles leaning on a center bar and the other stacks the tiles vertically. Both

designs have a storage area for the edging pieces in the front of the carts and bars on the

bottom of the cart (Dance Floor Caddies).

Since the cart needs to be able to go over uneven sidewalks, turn easily, and carry over

300 pounds, it requires wheels that can handle these constraints. Looking at products from

Uline, some wheel types included swivel, polyolefin, and rubber rigid casters with a size suitable

for the load of the tiles and the sidewalk (Casters).

Design Specifications

The client specified a certain safety factor and several obstacles the cart needed to

overcome. The dimensions of each tile are 4’x4’x¾” and because the weight of one tile is 47.2

lbs, 33 tiles weigh nearly 1600 lbs. The client asked for a cart which could carry 8 of these tiles,

or 400 lbs, at once. In addition, there are 16 straight and 11 edged metal pieces lining the

assembled dance floor which need to be transported as well. A straight piece is 4’ long and

weighs 4.2 lbs; a corner piece is 6’ ¼” wide and weighs 4.6 lbs.

Obstacles to keep in mind during this project included a 30” wide doorway, elevated

outdoor sidewalks, and a right-angled corner to maneuver. The cart would also have to be able

to deal with winter conditions. The client specified a need for wheels with at least 4” diameter

and the ability to turn. The VSC asked for a cart specifically designed to meet these

requirements, with any extra purpose (such as a flatbed cart) being unnecessary.

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III. Preliminary Designs

Brainstorming

After deciding what the major challenges were that needed to be addressed, the team

brainstormed many different ideas for general designs, materials, wheels, handles, bases, etc

(Murphy, John). Once the team had come up with as many ideas as possible, each team

member was instructed to come up with a design to bring for the next week’s meeting. At that

meeting, four smaller groups were formed and each person presented their idea within their

subgroup. After everyone had presented, each subgroup created one design that combined all

the ideas that they liked from their group members. However, two of these groups had

extremely similar designs and subsequently they combined early in the process, resulting in

three group designs at the end of the session. The next week, each group presented their

design to the whole team.

Cart Base-Wood (particle board, plywood, 2X4)-Aluminum-Steel (angle iron, 80-20)-Plastic (PVC, PE)-Composite (carbon, fiberglass)-Rubber

Wheels-Ball-bearing swivel-Metal-Casters-Rubber (Solid, bike-style)-Locking-3 vs. 4 wheels-Treaded-Plastic

General Features-Ramp (with rollers?)-Detachable handle/sides-Rubber (for corners)-Metal pipe (for frame)-Open sides to cart for “walk-in” loading-Clamps to hold tiles in place

Handles-Metal pipe-Wood-Plastic-PVC-Rubber/foam grip (time and budget permitting)-Removable

General Design-Metal frame/wood slats-1 piece of metal (for base?)-Permanent sides-Adjustable sides-Foldable sides-Side ramp vs end ramp-Slots for tiles-8X1 or 4X2 or 6X1 or 7X1 tile arrangement-Staggered tile placement

Table 1. Group Brainstorming Chart. The table represents the brainstormed materials and

designs for the cart.

Small Group Designs

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Because of the large number of group members, the design process began on a small

scale. As mentioned before, during the first session the team divided into smaller groups and

shared individual ideas, and each idea contributed to a design. The small group designs were

then presented to the whole team for editing and improvement. Through this process, the team

composed and began to make decisions on three solid designs: the Toaster, the Dual Flatbed,

and the Center Bar.

The Toaster (Figure 1) design allowed the tiles to take up the least amount of space,

having them stored vertically. Each tile fit in its own groove in the base and top. The amount of

material being used was minimal and the tiles were stored securely. Despite these positives,

there were flaws to this design. The first flaw was safety; sliding in the tiles would have had a

significant pinching hazard. The second flaw was usability; it would have been challenging for

the user to aim and slide the tiles into each slot. Finally, the third flaw was manufacturability;

creating these grooves, lined up exactly, would have been challenging.

Figure 1: The Toaster. A sketch of the first brainstormed design for the cart; shows the

unique features (grooves) and the dimensions.

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The Dual Flatbed (Figure 2) design allowed for versatility as well as functionality. Each

tile was held on the cart by slots near the handle and was also able to lean on supporting side

bars. The unique aspect of this cart was that all parts, except for the handle, are removable.

This allowed for a functional flatbed cart that can be used for various other tasks. However, the

team found that having removable parts raised issues related to manufacturability, usability, and

stability. Manufacturing would have been difficult because of the precision needed to align and

make parts be able to fit together. Usability would have been a challenge because with each

removable part there is a chance for it to become broken or lost. Finally, in general, when

something is removable it is not as stable as it would be if it were fastened. This was the largest

issue with this design, because stability was important when taking into account how much

weight had to be held.

Figure 2: The Dual Flatbed. A sketch of the second brainstormed design for the cart; shows

removable parts (dividers, handel), unique features (static/swivel wheels) and dimensions.

The Center Bar (Figure 3) was the most economic design, featuring a bar across the top

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in the center that the tiles lean upon, much like a teepee. The base was composed of two split

planks, reducing weight and material, but still supporting the tiles. There was a slot in the handle

to hold edging pieces, as well as clamps to prevent the tiles from falling out. The flaws in this

design includes stability issues with having only one bar connecting the front of the cart to the

back.

Figure 3: The Center Bar. A sketch of the third brainstormed design for the cart; shows unique

features (center bar) and the dimensions.

Design Evaluations

To decide between these three designs the team created a design matrix (Table #2).

This process highlighted the advantages and disadvantages of each design. By the end of the

preliminary design process the team decided on a way to combine the best features of each

preliminary design.

IV. Integrated Design

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Integrating Preliminary Designs

After deciding to go with the center bar design as the main feature of the cart, the group

used the best ideas from the rejected preliminary designs and incorporated them into an

integrated design.

From the Dual Flatbed design, one of the best features was that the flatbed increased

durability and safety by allowing the cart base to hold more weight. Having a flat surface for the

base also increases the versatility of the cart so it can be used for other purpose as well rather

than solely to transport the tiles because the client mentioned that such a need could possibly

arise.

From the Toaster design, safety was the most attractive quality since the tiles couldn’t

shift out of place or fall out of the space the grooves provided. Although the group did not

directly use this feature for the integrated design, a safety mechanism - a chain attached from

the front of the cart to the back on both sides - was inspired by the toaster and added to a later

design. This eliminated the need for clamps, which were present in the original center bar

design. The chain is an improvement over the clamps as it is much more easily manufactured.

When the cart is moving the tiles might sway if loaded incorrectly so the chains stop the tiles

from falling off the cart. This feature also ensured that while loading or unloading the cart, the

bulky tiles couldn’t fall out onto the person and cause injury.

Changes After Combining Preliminary Designs

First, the team realized that if two tiles were placed on opposite sides, they could collide

above the bar, which creates a potential of causing damage to the tiles, and could cause either

one or both tiles to fall away from the center and off of the cart. As a result, a second center bar

was included in the design. The group did calculations to figure out the minimum distance that

two bars needed to be apart in order for two tiles at the most extreme angle to not touch. This

distance was found to be four inches or more apart while the bar was at a height of 32 inches

from the base.

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Secondly, the base was changed from a full flatbed in the preliminary integrated design

to a partial flatbed. The partial flatbed consists of five two by four pieces lying sideways on the

cart base with gaps in between them. This base was chosen over a full flatbed because the cart

would only be used to move large objects that wouldn’t fall through the spaces in between the

two by fours. The reason why five pieces of wood were chosen because that was the maximum

number of pieces to ensure that the grooves on the dance tiles wouldn’t get caught between

and wreck the two by fours over time. The two supporting beams were to make sure the two by

fours would not warp as much over time, which in turn makes the cart more durable, which was

the director’s main concern. These beams also served the purpose of increasing the safety

factor by allowing more weight to possibly be held.

Finally, the last noteworthy refinement was adding two thin wooden pieces along the cart

near the center. The purpose of these pieces was to increase safety and ease at which the tiles

were to be loaded. When a person is loading the tiles onto the cart without these pieces, they

have to be careful that each tile is angled towards the center so that it does not immediately fall

backwards at them. With these pieces in place, there is no way they can load the tile (if touching

the center bar originally) with the bottom too far inward so that it is at an outward angle. They

are optimally placed so that there was still room for at least four dance tiles to be placed on

each side to meet the original 8 tile requirement given by the client.

Design Matrices

In the group’s original meeting with the client, he informed us of the most important

factors that the VSC was looking for in the cart. Of course it had to address the original need,

but he valued some details more than others. For example, he stressed the importance of

durability because this cart was to be used regularly and needed to be sustainable. The team

used a design matrix (Table 2) with factors based on the client’s priorities to determine which

would be the best overall design. Five main factors were isolated: ease of use, durability,

manufacturability, safety, and versatility. The weights for these were, respectively, 5, 5, 2, 3, and

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1. The reason for ease of use having maximum importance was that at the time one person was

meant to load, move, and unload the heavy tiles from the cart. As mentioned earlier, durability

was stressed by the client as the most important part, so that was also weighed heavily as an

important factor. Manufacturability was lower on the scale (with a weight of 2) because the team

started with plenty of time, an abundance of people, and three designs which were not overly

complicated. Safety had an average importance factor because, while the client didn’t

specifically stress it, the team agreed that safety is always an important factor, especially when

dealing with heavy materials and a product that will eventually be placed into a public area.

Lastly, versatility was at the bottom of the scale; when asked, the client emphasized the

importance of a specifically designed cart for the tiles instead of one with several applications,

although anything extra wouldn’t hurt. This design matrix helped the team narrow the ideas

down to two, the Center Bar and the Dual Flatbed. These two has relatively close scores in the

matrix while the other one was substantially less efficient based on our factors.

Importance The Center Bar The Dual The Toaster

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Factor Flatbed

Ease of Use x5 5 → 25 3.5 → 17.5 2.5 → 12.5

Durability x5 3 → 15 5 → 25 3 → 15

Manufacturability x2 3 → 6 4 → 8 3 → 6

Safety x3 3.5 → 10.5 3 → 9 4 → 12

Versatility x1 2 → 2 5 → 5 1 → 1

Total - 58.5 64.5 46.5

Table 2. Design Matrix. This design matrix narrowed our design choices to The Center Bar and

The Dual Flatbed.

Since the Center Bar and the Dual Flatbed designs were close in efficiency based on the

design matrix, the group decided to discuss and then vote on which one to manufacture. This

was done by modifying both potential designs to incorporate the best ideas from each initial

design. The center bar modifications included a flatbed but a bar across the center to hold tiles

at the top, with a lip at each edge on the bottom to prevent slipping. The dual flatbed

modifications included a lip at the edge, but no center bar. The only other change to this design

was making all parts non-removable. The team then drew up another design matrix to finalize

the decision. Based on the results, the Center Bar with modifications became the design of

choice. For the Center Bar, the factors of durability, safety, and versatility changed slightly,

whereas the factor of safety was the only change with the Dual Flatbed. Since the bottom was

changed to a partial flatbed, the Center Bar design increased in durability and versatility. The lip

on the edge increased the safety of both cart designs.

Importance Center Bar (with Dual Flatbed Toaster (not

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Factor modifications) (with

modifications)

applicable)

Ease of Use x5 5 → 25 3.5 → 17.5 -

Durability x5 5 → 25 5 → 25 -

Manufacturability x2 3 → 6 4 → 8 -

Safety x3 5 → 15 4 → 12 -

Versatility x1 4 → 4 5 → 5 -

Total 70 67.5

Table 3. Design Matrix 2. This design matrix proved The Center Bar to be dominant over The

Dual Flatbed.

Design Review

During the design review Scott, the group reviewer, asked several questions about

different aspects of the cart, both physical and analytical. He concluded that issues needing to

be addressed were mainly regarding the possibility of brakes on the wheels and regarding rust

prevention. Based on the overall weight of the cart and the tiles, he suggested that we add

brakes to at least two wheels in order to increase stability while loading and unloading the cart.

Also, seeing as most of the cart is made of metal, Scott mentioned that rust could be a major

factor in the future. In order to address this issue, the team bought primer and spray paint to

cover the metal and reduce future rusting.

V. Modifications for New Purpose

Explanation

During the week of March 17th-21st the dance floor tiles were removed from the VSC,

which required a rapid series of modifications to the design. The new purpose that was decided

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upon for the cart was to build it so it could transport the six plastic card tables at the VSC from

room to room, along with providing efficient storage. Taking into account the time restraints at

this point and the fact that all materials had been received already, there was no way to

drastically modify the plans. This resulted in a decision to slightly modify the design from the

dance floor tile cart in order to fit the new requirements (see design specifications below).

Problem Statement

The Verona Senior Center has six plastic card tables. They need to be transported

within the center through a doorway, over a threshold, and around corners, all performed by one

person. They currently have no way of doing this other than carrying them one at a time. We

plan to create a cart that can hold all six tables at once in order to provide easy transport and

storage. The cart will fit into a 24” wide wooden alcove that is currently being designed by

another team.

Design Specifications

There are six light card tables that need to be maneuvered within the VSC. They will be

moved around several times per week (see PDS for full specifications). When the team

contacted VSC about what they still required as well as any changes they thought were

necessary to the cart design, the client emphasized that only one bar would be necessary and

that the cart did not have to be a flatbed. Since there were no longer any edging pieces either,

the section in the front part of the cart (between the handles) was rendered unnecessary as

well. Also, the new design did not need to be as long as the last one because the tables were

smaller in all dimensions than the tiles.

Design Limitation Changes’ Effects on New Design

Design limitations are changes to the final product that would have been made if the

original design was to carry tables. First of all, the wheels wouldn’t have to have such a high

capacity, be required to go outside, and need brakes. Also the cart wouldn’t need as much steel

and could be constructed with more wood for the frame and bottom.

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VI. Preliminary Final Design

Measurements (With explanations of modifications)

The final design did not drastically change from the design for the tiles. The overall

structure of the cart remained the same with new design elements included; however, the

materials for the original design were purchased prior to the new director making changes, so

some parts are in surplus and some overspecialized, such as the wheels. The final design is

now modified to carry six tables instead of eight tiles, greatly reducing the required weight

capacity of the cart. One middle bar instead of two is needed since the tables would not need

extra space in order to lean (see calculations). Also, the length of the cart was shortened to

53.5” and the height reduced to 42.14 inches. The wooden boards on the bottom were reduced

to having five 2”X4”s of length 23.88 inches running perpendicular to the cart.

Figure 4: Sketch of final design:

Shows general plan for final design before

fabrication

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VII. Fabrication

Methods

(Day 1, 4/2)

The group started by cleaning off all the metal with acetone. Each individual piece was

rubbed down 2-3 times to clean off oxidation and impurities. After the metal was cleaned, the

group sorted the metal. To begin, the pieces for the base were cut so they could be welded

together. Two of the 2x2 square steel tubings were measured out and marked at the 24 inch

mark and the two 2x2 angle iron steel pieces were marked at the 44 inch mark, all with a

sharpie marker and tape measure. Then the four 2x2 tubes and angle iron were taken to the

drop saw. Coolant was applied to the cut marks and the 2x2s were clamped into place. Then

the saw was placed to slow cut for the steel and slowly lowered onto the metal to cut it. This

was repeated for all four 2x2 pieces.

The angle iron was measured out to pre drill holes for the wooden bars that will go

across the frame. With two pieces of the cut angle iron, three holes were drilled with a center

drill, followed by a ⅜ inch drill bit. The first hole starts 11 inches from the end of the angle iron

with the spacing between each hole being 9 inches. All four pieces (two angle iron and two

square stock) were then taken into the welding shop and welded together to create the base

frame.

After the base was welded, most of the remaining metal pieces were measured and cut.

The center bar that goes across the top was measured out to 42 inches and cut by the same

method as the other metal. The angle iron for the uprights was cut to 32 inches by the same

means.

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Figure 5: Cutting the steel tubing

Shows method for cutting the metal into pieces

(Day 2, 4/9)

The team split up into 3 different groups for fabrication. One group worked on sanding

the base wood down by an eighth of an inch so that it would fit in the frame that was welded the

week before. Another group worked on grinding the welds that had already been created on the

bottom of the frame so that the base would be flush and the wheels could be bolted in easily to

the frame. The last team worked on welding the uprights that would then be attached to the

frame later via welding. One inch angle iron was used for the uprights that were welded to a

piece of one inch square stock steel on the base.

The holes that would need to be drilled for the wheels were marked by placing each wheel

down and outlining the holes onto the frame with sharpie. Next, the frame was taken to the drill

press and center punched as coolant was applied. Finally, a ⅜ inch drill bit was used to drill

through the steel. If a bolt did not go easily through, the hole was opened using a countersink.

This drilling process was done 11 more times, getting three bolts in the steel frame and one bolt

in each one of the pieces of wood for each wheel. Next, the group lined up the wood with the

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previously drilled holes on the angle iron and drilled the holes in the wood.

Figure 6: Drilling holes for bolts

Shows the team’s method for drilling holes in the metal with a drill

press.

(Day 3, 4/16)

Again the team split up into different groups. One group started the welding of the

handle and back upright part of the frame onto the base. The other groups worked on cutting

the metal for the rest of the frame and counterboring the wood so the bolts would not stick out of

the bottom of the cart and damage the tables. To cut the metal, one group took the 1 inch angle

iron and measured 13 and 7/16 inches to make a support for the handle. This created a right

triangle with 45 degree angles to help support the handle. Also, the metal had to be cut at 45

degree angles so it could be welded to the handle. After measuring and drawing in the cut at a

45 degree angle, the metal was taken to the drop saw. The saw was turned to a 45 degree

angle and then used to cut the angle iron with coolant. This was then repeated for the other 1

inch angle iron so both of the supports were ready to be welded.

The uprights were welded to the base of the cart and then the top pieces of the handle were

welded onto the uprights. Lastly, the center metal tube was welded across the cart onto each

end of the cart at the top of the uprights. At one end of the tube a gap was left in the weld to

prevent gas to collect inside the tube. At the same time, a different group went to counterbore

the existing holes in the wood. They had to acquire the correctly sized bit to open up each hole

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to fit a ¾ inch washer. They used a drill press on each of the eight holes.

Figure 7: Welding the frame

Displays the base frame of the cart base as it is about to be

MIG welded

(Day 4, 4/23)

On this day all of the metal and wood was spray painted black (after the wood had

primer applied to it first). For the next week the pieces all were allowed to dry.

(Day 5, 4/30)

The wooden 2X4s were bolted to the base metal to create a platform for the tables to

rest on. Then, the wheels were bolted onto the bottom of the base, and the cart was finally

functional and ready for some last testing.

Testing and Analysis

After completing the fabrication of the cart, it was necessary to test aspects of our final

product such as maneuverability and load capacity. To do this, the team simulated a load by

putting a person on the cart and maneuvering around hallways. After extensive testing with the

cart, it was concluded that it is easiest to turn the cart and maneuver it with the swivel wheels in

the back. After moving the swivel wheels to the back and the fixed-direction wheels to the front,

a person was again placed on the cart and pushed around. This helped to prove that the cart is

easily maneuverable around corners with a load of approximately 150 pounds.

In addition, the team reviewed the safety features of the cart. The lip on the base was

not sufficient in supporting a piece of plywood of approximately the same length and width as a

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card table. Due to this issue, a higher lip made of wood was added to the outside of the cart to

stop the tables from slipping off.

To test load-bearing capabilities three people weighing 150, 170 and 165 pounds all

stood on the cart at once and it was pushed around without breaking or flexing, showing that the

cart can hold more than 485 pounds, well above the desired 30 lbs for the tables. The strength

of the center bar was tested by having a person weighing 150 lbs hang off of it to see if anything

broke or moved, which it did not.

Data Interpretation

The above data shows that the cart is very strong and will easily satisfy the weight

requirements of the client. Additionally, the center bar clearly will not bend or break when the

tables are leaned against it, even if the Verona Senior Center acquires new, heavier tables.

Finally, adding the wood pieces along the sides was an important result of recognizing that the

original metal lips were not a sufficient safety feature.

Load Calculations:

For tables

(4 wheels)(lb held per wheel)/((wt of table)(number of tables)+wt of cart)

(4 wheels)(410lb)/((5lb/table)(6 tables)+99.61lb )=12.7 factor of safety

For dance floor tiles

(4 wheels)(410lb)/((47.2lb)(8 dance floor tiles)+(6 side pieces)(5lb)+99.61lb)=3.2 factor

of safety

VIII. Final Prototype

Summary of Final Design

Final Dimensions:

-Length of frame 44 ⅛ inches

-Length of handle 9 ½ inches

-Height of frame 35 ¼ inches

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-Height of frame and wheels 43 inches

-Width of frame 24 inches

The final design has the pole down the center of the frame to separate the tables on two

sides.This is used so the tables can rest up against the pole and be transported easily. The

wheels in the back swivel, increasing maneuverability. On the top of the frame we built an

extended handle to allow easier handling for the user. The length of the frame was determined

by the dimensions of the tables and the width was determined by the accessibility of the doors

in the senior center. Also, the wheels are extremely strong ensuring the durability and longevity

of the cart with two of the wheels on swivels to allow for easier maneuverability.

Figure 8: Finished cart

Completed cart with general dimensions

Materials and Costs

The materials the team chose to use were steel for the frame and pine 2x4s for the

base, along with rubber caster wheels. Steel was chosen because it is strong enough to hold

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the tiles (or tables) and it is relatively cheap but much easier to weld together than aluminum.

The 2X4s were chosen due to their strength and cheap price, along with them being very light.

Also there were some in the shop already so none needed to be purchased. Concerning the

wheels, the rubber caster wheels are very strong, can go over the sidewalk cracks that are at

the Verona Senior center, and they are extremely durable, which was a key client requirement.

The final expenditure total for the project was $326.51, which is about $26 over the

original budget. This was broken up into approximately $186 for the metal frame pieces, $96 for

the wheels, $12 for paint, and $32 for the miscellaneous materials (bolts, etc). The only time the

budget truly affected our design was when it came to the wheels, because there was a wide

variety of options in terms of which wheels to choose and how high quality (expensive) they

could and should be for the client’s needs (see XII for details).

Design Limitations

The main design limitations dealt with the budget, the dimensions, and the time frame to

complete the project. We were given a 300 dollar budget to manufacture the cart. The

dimensions are important because the cart has to be able to easily move through doorways and

be stored in a closet. Also, we were only given 11 weeks to finish the project and deliver it to the

customer.

IX. Conclusion

Problem

The Verona Senior Center desired an efficient method to transport their six plastic card

tables from one room to another within the center. They also wanted to be able to use whatever

method is devised (in this case, a cart) to provide storage for the tables as well.

Final Design

The final design for the cart consists of a metal frame measuring 24”X44” at its base and

a height of 42.1 inches. At the top of the cart there is a central bar running lengthwise in the

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middle of the cart for the tables to lean on. The handle is also made of metal, and is angled

outward at 45 degrees from the vertical to make pushing the cart around more convenient. The

metal base frame has five wooden 2”x4”s running widthwise to provide a surface for the tables

to rest on. It is painted black as a rust prevention measure.

What the team learned from the project

One of the biggest challenges the team had to overcome was coordinating the work that

every member was doing, considering that there were 17 people on the team. For the first few

weeks the team struggled to be productive because not everyone was able to voice their

opinion or contribute to the project. This was exacerbated by the fact that a majority of the

conversation took place at one end of the table and at the other end it was difficult to hear what

was being discussed. However, after about three weeks this issue slowly went away as the

team became more comfortable with each other and broke into three smaller groups to work on

separate pieces of the project.

Another learning experience for the team came the week after spring break. Upon

arriving to the lab after a week off, team members were informed that there was a change in

leadership of the client business, as the director of the VSC changed. This in itself didn’t present

a major problem until the team also discovered that the dance floor tiles no longer were in use

at the VSC and the cart as had been designed for almost two months was consequently not

needed either. This situation, while unfortunate, did provide a valuable learning opportunity

when the design had to be modified at the last minute to meet the new need at the VSC, moving

plastic card tables. Thankfully this change didn’t require any drastic modifications, as the budget

had already been reached and all materials ordered with the old design in mind.

This leads to a new issue that needed to be addressed, namely ensuring that the budget

provided to the team was approximately equivalent to the budget the team actually spent. This

didn’t cause any major issues seeing as the budget of ~$300 was large enough to purchase a

large quantity of metal for the frame, and also to purchase four heavy duty caster wheels. It did

24

however limit the choices of material that were available, which was a difficult decision to make

considering the team’s desire to create a cart that is both durable in the long term and fairly light

and maneuverable.

Design Limitations (those addressed and those not)

In the end, the team far exceeded the design limitations in that the original plan was to

hold 400 lbs at a time on the cart, but now the cart only needs to hold about 30 lbs. This was

somewhat countered by the reduction of the height and length of the cart due to the tables being

smaller than the dance floor tiles, but the final fabricated cart still has a safety factor of about 12

which is far beyond the factor of two that was the goal. Additionally, the cart most definitely will

be durable enough for a very long time seeing as it is made almost entirely of steel but will only

be holding plastic tables. Finally, the threshold between rooms will be easily maneuvered over

since the wheels that are on the cart were originally intended for the far more rigorous trip

across outdoor pavement and cracks in the ground.

X. Future Work

While the team is satisfied with the work they have done to create an efficient cart for

table transportation, there are several things that could be changed to optimize the final product.

First of all, if the team had been able to design for the new purpose for as long as for the old

purpose, they would have created the cart using less steel and more wood seeing as the card

tables don’t put nearly as much stress on the cart as the dance floor tiles would have.

Additionally the design could possibly be modified to address the smaller amount of table

compared to dance floor tiles, possibly by removing the center bar and leaning the tables a

different way, or using the slot guides that were a possible idea for the dual flat bed cart idea.

25

XI. References

Casters. Uline. http://www.uline.com/BL_1877/Casters. Last updated 2014. Accessed February

12, 2014.

Lecture: “Professional Design Process, IDEO video.” UW-Madison, Intro to Engineering 160.

February 6, 2014.

Murphy, John. Lecture: “1st Design Lecture.” UW-Madison, Intro to Engineering 160. January

30,

2014.

Portable Dance Floor Caddies. Sico, Inc. http://www.sicoinc.com/dance_floor_caddies.php. Last

updated 2013. Accessed February 12, 2014.

26

XII. Appendix A: Materials List, Cost, and Quantity

Card

Table

Cart

Description Length/

PN

Price QTY Total Date

Ordered

Date

Shippe

d

Date

Arrived

1/8" x 2" x 2" Angle, A-36 Hot

Rolled Steel

60" $ 15.66 2 $ 31.32 3/11/2014 Pick-Up 3/23/2014

2" Sq x 1.760" ID x .120" Wall

Square Steel Tubing

24" $ 9.72 2 $ 19.44 3/11/2014 Pick-Up 3/23/2014

1/8" x 1-1/2" x 1-1/2" Angle, A-36

Hot Rolled Steel

36" $ 7.29 4 $ 29.16 3/11/2014 Pick-Up 3/23/2014

1/8" x 1-1/2" x 1-1/2" Angle, A-36

Hot Rolled Steel

18" $ 3.74 1 $ 3.74 3/11/2014 Pick-Up 3/23/2014

1-1/2" Sq x 1.260" ID x .120" Wall

Square Steel Tubing

24" $ 8.23 3 $ 24.69 3/11/2014 Pick-Up 3/23/2014

1/8" x 1-1/2" A-36 Steel Flat, Hot

Rolled

12" $ 1.45 1 $ 1.45 3/11/2014 Pick-Up 3/23/2014

27

1/8" x 1" x 1" Angle, A-36 Hot

Rolled Steel

18" $ 2.52 1 $ 2.52 3/11/2014 Pick-Up 3/23/2014

1/8" x 1" x 1" Angle, A-36 Hot

Rolled Steel

36" $ 4.91 2 $ 9.82 3/11/2014 Pick-Up 3/23/2014

1/8" x 1" x 1" Angle, A-36 Hot

Rolled Steel

60" $ 8.03 2 $ 16.06 3/11/2014 Pick-Up 3/23/2014

1/8" x 1" A-36 Steel Flat, Hot Rolled 18" $ 1.43 1 $ 1.43 3/11/2014 Pick-Up 3/23/2014

1" OD x 0.834" ID x .083 Wall DOM

Steel Tube

60" $ 23.22 2 $ 46.44 3/11/2014 Pick-Up 3/23/2014

SUBTOTAL $ 186.07

Shipping N/A

TOTAL $ 186.07

6 x 2" Rubber Rigid Caster H-

3326R

$ 18.00 2 $ 36.00 3/11/2014 3/12/20

14

3/13/2014

6 x 2" Rubber Swivel Caster with

Brake

H-

3326S

WB

$ 23.00 2 $ 46.00 3/11/2014 3/12/20

14

3/13/2014

SUBTOTAL $ 82.00 3/11/2014 3/12/20

14

3/13/2014

Shipping $ 14.23

TOTAL $ 96.23

Hex Hed Bolt 3/8-16 879152

03

$ 0.22 50 $ 11.22 3/12/2014 3/14/20

14

3/26/2014

Flat Washer 3/8 Screw 677466

02

$ 0.06 100 $ 4.07 3/12/2014 3/14/20

14

3/26/2014

Hex Nut 3/8-16 674711

28

$ 0.06 100 $ 6.02 3/12/2014 3/14/20

14

3/26/2014

28

SUBTOTAL $ 21.31

Shipping $ 10.98

TOTAL $ 32.29

Painter's Touch Ultra Cover 2X Flat

Black Primer Spray - 12 oz

557477

7

$2.98 2 $5.96 3/12/2014 Pick-Up 3/26/2014

Painter's Touch Ultra Cover 2X Flat

Black Spray Paint - 12 oz

557479

4

$2.98 2 $5.96 3/12/2014 Pick-Up 3/26/2014

TOTAL $11.92

Pine 2X4s 6’ 0 2 0 NA NA NA

GRAND TOTAL (3 orders) $ 326.51

XIII. Appendix B - Timeline as a Gantt Chart

Gantt Chart

29

XIV. Appendix C - Product Design Specifications

There are 6 card tables and the dimensions of the card tables are 36”x36.5”x2”. They

weigh about 5 pounds each for a total of 30 pounds. Because the card tables are stored inside

the building, the cart does not need to go over any bumps in pavement. It does however need to

clear a threshold of a doorway between the room the tables are used in and the room they are

stored in. Also the cart will be used much more frequently, about 2 or 3 times a week so it must

be able to withstand frequent repetitive use. Finally, the cart also may be used as a permanent

storage platform for the tables when they are not in use, so it must not flex or wear down if the

tables rest on it for long periods of time.

30