design project 1: shopping cart · team 5 ii executive summary this paper discusses the design of a...

Submitted by:

Nadine Geagea, Dominick Forlenza, James Smith, Maria Hudock, Junghun Kim

Submitted to: Dr. Xinli Wu

July 29, 2015 EDSGN 100 July 29, 2015

Introduction to Engineering Design Section 204, Team 5

Design Project 1: Shopping Cart

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Executive Summary

This paper discusses the design of a foldable, easy-to-use shopping cart that can hold 100 pounds and costs less than fifty dollars to produce- unless serving multiple purposes. Customer-needs

assessment and the Internet helped determine suitability for groceries and durability most important to shoppers. Cheap, strong materials were appealing and allowed profit.

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Table of Contents

1. Cover Page…………………………………………………………………….…..(Nadine)

2. Abstract (Dominick) ……………………………………………...…………………ii

3. Introduction 3.1 Issue Summary (James).….…………………....……………………………………1

4. Description of Design Task 4.1 Problem Statement (James)………………………………..……………….….……1 4.2 Mission Statement (James)……………………………………………………....…1 4.3 Design Specifications (James)………………………………..……………………..1

5. Design Approach 5.1 Project Management (Gantt Chart) (Nadine).…………………….….…………….2 5.2 Customer Needs Assessment (Maria)….………………………………………..…3 5.3 Concept Generation (Maria)……….……………..……………………..………....3-6 5.4 Design Selection Matrices (Maria)………….…………………………….………..7-9

6. Final Design and Prototype 6.1 Working Drawings (Maria, Kim, James)…………………...…..…… …….……9-10 6.2 Prototype Scale and Images (Maria)………….……..………………….……….…11 6.3 Design Features (Nadine)…………....….……..……………………….….…….…11-12 6.4 Operation Instructions (Nadine and James)….……..………………….….……….12

7. Engineering Analysis 7.1 Working Mechanism (Kim)……………....….……..…………………….…...……12-13 7.2 Cost Analysis (Kim)…………….……..………………….….………………….…14

8. Conclusion 8.1 Summary (Maria)………….……..………………..…………..……………….……14-15

9.Acknowledgements (Nadine) ……………………………………………………………….15

10. References (Dominick)………………………………………………………………………16

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3. Introduction

3.1 Issue Summary In New York City and other highly populated areas it is often difficult to find a way to transport groceries due to the lack of vehicles and due to high-rise buildings. The Engineer’s solution: to build an economical and storable cart. The team conducted a survey was to see what individuals cared most about in a collapsible shopping cart. The findings resulted in a shopping cart that had a variety of storage areas, collapsible, and affordable.

4. Description of Design Task

4.1 Problem Statement Consumers need an easier way to transport groceries by foot after leaving the store. The transportation means must have a reasonable capacity and be collapsible for easy storage. 4.2 Mission Statement In order to provide a more convenient and reliable means to transport consumer goods by foot at a minimal cost, a collapsible cart with set capacity was conceptually designed and evaluated. 4.3 Design Specifications

• The shopping cart’s bottom frame 3ftx1.5ft with a 3/4” thickness

• The height was 3ft. The top frame for delicates is 1.5ftx0.75ft with a 3/4” thickness • The top and bottom frame are collapsible to the main frame, which is 3ft tall. • The shopping cart has two different compartments the top being for eggs, bread, and

other delicate grocery items. • The bottom could be used for any other groceries (water, soda, other bulky items) the

folding shopping cart material altogether came to a total of $32.57. • The shopping cart has a weight capacity of 150 pounds.

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5. Design Approach

5.1 Project Management (Gantt Chart)

Table 1. Gantt Chart

Team 5 Cart Gantt Chart

Task Start Date End Date Completion

Week 1

Week 2

Week 3

Week 4

Week 5

(7/1) (7/7) (7/14) (7/21) (7/28)

Establishing goals and scheduling 2-Jul

100%

Information Gathering 2-Jul

100%

Cost and Risk Assessment 9-Jul

100%

Brainstorming 2-Jul

100%

Design Matrix Selection 9-Jul

100%

Set of Working Drawings

(BluePrints) 14-Jul

100%

Build and Test Design Prototypes 14-Jul

100%

Evaluate Design Prototypes 14-Jul

100%

Design Documentation and

Presentation 21-Jul

100%

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5.2 Customer Needs Assessment A questionnaire was distributed to evaluate customer needs and preferences in basic considerations as well as specialty areas. Below are the summarized results of the distributed survey.

• Audience reported going to the grocery store between 1-8 times every 2 weeks. • Most use a car to transport groceries greater than 5 miles, while a cart was reported as the

method of transport for a half-mile commute. • A range of 2-15 grocery bags per trip was reported. • Commute lengths ranged from 5-30 minutes. • Terrain considerations were stairs, uphill sidewalks, crowds, slower-moving elderly

people in area, and hot cars (consideration for cold foods). • Most important factors to the audience were having separate compartments to keep

crushable/breakable foods safe, raw meat separate, cold foods preserved, comfort and speed of use.

• Most consumers would not prefer to pay more than $20 for a cart. • Average scores for qualities rated on a scale of 1-5 (5 is most important):

Table 2. Average Design Scores Ease of use: 4.8 Durability: 4.8

Weight capacity: 4.3 Collapsibility: 4.2

Cost: 4.0 Weight of cart: 4.0

Safety: 3.8 Attractiveness: 2.2

These results were used to drive creative design features and to determine and factor importance for the weighted design matrix. The initial six designs inspired by these criteria follow. 5.3 Concept Generation The team members each developed 3-5 rough sketches to represent various cart concepts. After discussing each, the following six designs were chosen to continue for further evaluation.

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DESIGN A: Premade Baskets

Figure 1. Design A

DESIGN B: Folding Briefcase

This extremely compact design focused on ease of use, collapsibility, and

attractiveness. The flat, compacted cart could be carried easily in the hand,

looking as stylish as a standard briefcase. Flaps fold up from each side of the case

and are stuck together with Velcro to form a wagon-like cart with telescoping dragging handle for use. Straps are also

used to hold the case together when entirely folded. Caster wheels swivel in and out of grooves in the case for even

flatter storage. Figure 2. Design B

After browsing online for cost-contained materials, a simple design utilizing premade grocery baskets in a minimal metal frame was conceived. With this design, groceries would be placed in baskets that rested in a collapsible frame. The baskets could be removed for easy unloading of groceries. After, the frame would fold up and be placed in the stackable baskets for storage.

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DESIGN C: Zipper Collapsible

This cart design focused on collapsibility and easy item

removal. It can be made extremely compact because of simple cloth construction on top of a rolling platform. A zipper runs from the base to

the top of the expanded cart by circling around it several times, allowing for either internal divisions or for

optional sizes. The more the cloth is zipped, the larger the

volume of the higher bag. The more the cloth is unzipped, the

larger the fabric strap for pulling and the easier the

access to items towards the bottom of the cart no bending

and reaching into the cart). A handle is used to pull the rolling platform around. Figure 3. Design C

DESIGN D: Nylon Strap Foldout

This design makes use of very durable yet economical materials and simple design. A metal frame forms two platforms suspended and spanned by strong nylon straps. A small upper basket keeps breakable groceries separate from large items on the bottom. Straps allow the frame to fold up into a tall and flat storable form. Figure 4. Design D

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DESIGN E: Fishnet Basket with Scooter

This design incorporates a fold-down scooter foot board to make pushing easier and add a second use. A fishnet basket holds a large volume of goods without adding a lot of weight, while nylon straps across the bottom support heavier items. The basket folds down and the bottom platform and scooter boards fold up to yield a wider-than-others, but still compact, folded cart. A handlebar serves both to guide the scooter/cart and to carry the folded item.

DESIGN F: Accordion Folding Cart This design works like the compressible water bottles of a stiff plastic. It can be expanded by pulling up the plastic walls to be self-supporting, and a bit of downward effort on the top faces gives a compressed form. An inner shelf sits between the plastic ridges to separate food items. Items can be loaded through the removable top (bottom is accessed by removing shelf). The upper container rolls on a flat platform on caster wheels. Figure 6. Design F

Figure 5. Design E

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5.4 Design Selection Matrices

After initial concept generation, the six concepts above were evaluated in a simple design matrix using Design A as the standard. Table 3. Simple Design Matrix

Simple Design Matrix - Project I

Design A - Premade Baskets

Design B - Folding Briefcase

Design C - Zipper Collapsible

Design D - Nylon Strap Foldout

Design E - Fishnet Basket with Scooter

Design F - Accordion Folding Cart

Ease of use 0 -1 -1 0 -1 0 Suitability for groceries

0 0 -1 0 0 -1

Collapsibility

0 0 1 1 -1 1

Cost of materials

0 0 0 1 -1 -1

Weight capacity

0 0 0 1 0 0

Safety 0 0 1 1 -1 -1 Durability 0 -1 -1 1 -1 -1 Sum + 0 0 2 5 0 1 Sum - 0 2 3 0 4 4 Sum 0 7 5 2 2 3 2 Net Total 0 -2 -1 5 -5 -3 Rank 2 4 3 1 6 5 CONCLUSION: keep?

Yes Revise/combine?

Revise Yes No No

Designs A and D were chosen to continue with potential for improvement, with Designs B and C chosen to continue as ideas for modification/inclusion.

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After modifications of the designs that were retained from the first design matrix, a second design matrix was used to select the final concept. The categories of consideration were ranked based on the average rating on a scale of 1-5 given by consumers to the area, converted to a percentage.

Table 4. Weighted Design Matrix

The modified version of the original Nylon Strap Foldout cart was chosen to be developed into a conceptual prototype.

Weighted Design Matrix - Project I

Standard - Premade Baskets

Folding Briefcase

Nylon Strap Foldout - Modified

Zipper Collapsible Modified

Weight Score

Weighted Score

Score

Weighted Score

Score

Weighted Score

Score

Weighted Score

Attractiveness

0.43 3 1.29 3 1.29 3 1.29 2 0.86

Ease of use

0.83 3 2.49 3 2.49 4 3.32 3 2.49

Suitability for groceries

0.97 3 2.91 3 2.91 5 4.85 2 1.94

Collapsibility

0.80 3 2.40 4 3.20 4 3.20 5 4.00

Cost of materials

0.87 3 2.61 2 1.74 2 1.74 4 3.48

Weight capacity

0.77 3 2.31 5 3.85 5 3.85 3 2.31

Safety 0.80 3 2.40 3 2.40 4 3.20 3 2.40 Durability 0.97 3 2.91 2 1.94 4 3.88 3 2.91 TOTAL 2 19.32 19.82 25.33 20.39 Ranking 4 3 1 2 Conclusion: keep?

no no yes no

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6. Final Design and Prototype

6.1 Detail Drawings Figure 7: Detail 1

Figure 8: Detail 8

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Figure 9: Detail 7

Figure 10: Detail 4

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6.2 Prototype Scale and Images

Scale Used 1:4 Figure 11: Prototype Photos

Figure 12: Cart Drawing with BOM 6.3 Design Features One of the main design features is the collapsibility of the cart and the fact that it takes up minimal space, as shown in the working mechanism and working drawing. The cart is also able to withstand over 100lb of force, with a rating of 150lb. The cart also has multiple compartments

Scale Used 1:8

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that are available to store delicates on the top basket and more bulky items on the bottom. This is more than just a traditional shopping cart, with added hooks to store more groceries. There is a specific place for each different type of grocery. Coupled with its lightweight frame for easy travel, this cart is simple to use but practical at its core. 6.4 Operation Instructions Collapsing the cart

1. Unhook top basket from mainframe. 2. Lift up the back of the top basket until it’s parallel with the handle bar. 3. Lift up the bottom unit until it is parallel with the handle and top basket part. 4. It is now in its fully collapsed stage and is ready for storage.

Setting up the cart for use

1. Pull the bottom basket down until it is fully secured on the ground. 2. Push the top basket down until it is aligned with the bottom basket. 3. Hook the top basket to the mainframe to fully secure it by resting the hook on the main

bar. 4. Cart is fully assembled and ready for use.

* Weight capacity is 50lb on the top basket and 100lb on the bottom basket.

7. Engineering Analysis

7.1 Working Mechanism

In order to make a strong and collapsible storage space, a hooked frame with a triangle profile was used. Swivel connection enables the frame to fold to a smaller form. By using hook attachment, the base leg of the right triangle detaches from the vertical frame and folds inside it. To make sure the frames fold parallel to each other, each vertical pole set (blue, orange, green) is positioned at a different width. A hook device locks the swivel frames in place for use.

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Figure 13. Working Mechanism 1

On the upper cart basket, the

triangle frame holds up the basket, but the bottom design needed swivel connection and fixed connection at the same time to withstand the weight and to fold in to save space. To solve this problem, a rotating locking device was used to hold the vertical frame from falling. The brake doesn’t stagger the folding mechanism (block bottom frame and upright frame from folding parallel) because it rotates to the side.


The cart is made of 3 big frames: Triangle hook frame, Vertical frame, and Horizontal frame. In order to make these frames fold into each other, swivel connection was used in connecting these 3 big frames and to make sure they are not interfering with each other’s folding, Triangle hook frame is located in inner level, Vertical frame is in middle level, and Horizontal frame is in outer level.

After cart is folded, another nylon strap is located on the handle so that user can tie the cart and keep the folded form without opening.


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7.2 Cost Analysis

Rather than using a solid material like a traditional cart, a combination of hollow framing and meshing was used, saving expenses of materials. Cheap, durable material was needed for the meshing. Nylon was ideal due to its durability and the characteristic of it being fabric. By using nylon instead of solid metal to make the base, cost and weight was reduced dramatically while maintaining superior durability. Cotton net was used as a guardrail for the goods on the basket. It also allows for it to be attached to the triangle hook frame, and when it is collapsed, not get caught. However, for future models of the cart, plastic could be utilized rather than the aluminum used for the bars, should a more economical plastic be found that meets the needs that of these poles. Also, netting could be bought in bulk as opposed to for a single cart to reduce costs.

8. Conclusion

8.1 Summary Through this project, the team gained valuable exposure to the specific steps of the design process. The team also learned how to work effectively with, and the benefits of having, a variety of team members. From learning effective concept generation strategies, to the importance and surprising insight of customer needs surveys, to working efficiently with a limited budget, to the technical difficulties of constructing a conceptual prototype, to communicating unique and innovative problem-solving perspectives, each new experience helped the team members to become more creative and critical thinkers.

Some improvements could be made to the prototype design. It was discovered during prototype building that there was not a sufficient locking mechanism to keep the cart posts upright. A small break was added, but in a larger product, a more complex or sturdier locking system might be needed. Improvements in the members themselves that the team will work on for the next project are increased communication, time management, and dispersion of work. Also, the team will continue to build a knowledge base of how to design and build prototypes, including specifying tasks and locating materials.

Some small bad experiences emerged from the team members being new to the design process: it was at first difficult to define the path to the final product and to locate materials. Through experience, the team became much more comfortable with the process. Another

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downside was discovering that there was no locking mechanism on the cart to hold it upright, but it was resolved with a last-minute and creative fix.

A suggestion for future implementation of this project is to include more specific requirements for certain steps, mostly in the report format. Examples provided by previous design teams aided to specify what was necessary to include in the introduction, abstract, etc. More examples like this would be helpful.

Overall, the team had an amazing experience working with members from different backgrounds, learning each others’ strengths and weaknesses, and building the best prototype possible given the time and resource constraints. Each individual provided excellent constructive criticism and creative insight that will be utilized in bettering everyone’s Engineering Design capabilities.

9. Acknowledgements

The team would like to thank Dr. Xinli Wu for his assistance and contribution to this project, and

also The Pennsylvania State University’s SEDTAPP in the College of Engineering.

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References

1. The Home Depot, 'Allied Tube & Conduit 3/4 in. EMT Conduit-101550 - The Home Depot', 2015. [Online]. Available: http://www.homedepot.com/p/Allied-Tube-Conduit-3-4-in-EMT-Conduit-101550/100400406. [Accessed: 13- Jul- 2015].

2. Mcmaster.com, 'McMaster-Carr', 2015. [Online]. Available: http://www.mcmaster.com/#brass-grommets/=y7k5zb. [Accessed: 13- Jul- 2015].

3. Mcmaster.com, 'McMaster-Carr', 2015. [Online]. Available: http://www.mcmaster.com/#catalog/121/3544/=y7k32y. [Accessed: 13- Jul- 2015].

4. Mcmaster.com, 'McMaster-Carr', 2015. [Online]. Available: http://www.mcmaster.com/#catalog/121/2970/=y7k5pb. [Accessed: 13- Jul- 2015].

5. Mcmaster.com, 'McMaster-Carr', 2015. [Online]. Available: http://www.mcmaster.com/#nylon-wheel-standard-casters/=y7k582. [Accessed: 16- Jul- 2015].

6. Mcmaster.com, 'McMaster-Carr', 2015. [Online]. Available: http://www.mcmaster.com/#catalog/121/1547/=y7k3iy. [Accessed: 20- Jul- 2015].

7. Mcmaster.com, 'McMaster-Carr', 2015. [Online]. Available: http://www.mcmaster.com/#string-ties/=y7k4ru. [Accessed: 20- Jul- 2015].

8. Amazon.com, 'Amazon.com: Beistle 50301-BK Decorative Fish Netting, 4 by 12-Feet: Kitchen & Dining', 2015. [Online]. Available: http://www.amazon.com/Beistle-50301-BK-Decorative-Netting-12-Feet/dp/B001MQBJV0. [Accessed: 20- Jul- 2015].

design project 1: shopping cart · team 5 ii executive summary this paper discusses the design of a...

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