Retractable umbrella
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Contents |
Executive Summary
Major Stakeholders and Their Needs
Four major stakeholders were identified in the life cycle of the umbrella: the consumer, the retailer, the manufacturer and the distributor. The following table summarizes the needs and desires of each stakeholder. Each of them is described in detail in the following subsections.
Stakeholder | Needs | Desires |
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Consumers |
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Retailers |
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Manufacturer |
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Distributors |
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Consumer
An umbrella is a product commonly used by people to refuge from rain and other environmental phenomena. Most people have had at least one umbrella in their lifetime, therefore consumer diversity was considered during the evaluation of their needs. The requirements of the consumer can be summarized as:
- Rigidity: the product needs to be able to support itself in the hands of the person using it.
- Portability: consumers want a product that they can carry around all day, they need a product that is compact and easy to carry.
- Appearance: the products should appeal the consumer.
- Low cost: as a product that users carry all day, umbrellas tend to be lost or forgotten often. A low cost device could be replaced more often, than an expensive one. In addition, many consumers would not want to spend a large amount of money in a commonly used object.
- Safety: umbrellas have many small components and outstanding elements, they need to be safe for people to use.
- Durability: consumers want a product that does not need replacement often
- Light-weight: commonly, consumers carry umbrellas all day with them, most would opt not to carry or use it if it is too heavy.
Retailer
The fact that umbrellas are commonly used object makes their market a competitive one. Retailers needs are focused on making their product profitable. The following list summarizes their needs:
- Appearance: the product needs to be appealing to the consumer to be competitive .
- Price: the product needs to have a reasonable price that will yield revenue.
- Reliability: the product needs to be reliable, since its reputation reflect on the name of the retailer.
- Safety: the product needs to be safe, since the retailer is responsible for accidents that an error in the product could cause.
Manufacturer
Manufacturers want to minimize the cost and time of manufacturing processes. The following list summarizes their needs:
- Simplicity of the design: manufacturers need a simple design with simple geometries
- Modularity of the design: manufacturers need a modular design that optimizes the processes of manufacture.
- Materials: low cost and non-toxic materials minimize the cost of the manufacture.
- Manufacturing process: low cost
- Storage: minimum the weight and overall dimensions make the object easier to store and transport.
Distributor
Distributors want to minimize the cost and time of distribution of the product. The following list summarizes their needs:
- Compact: the product needs to be easy to pack and able to survive distribution
- Modularity: the product needs to have modular replacement parts
- Storage: minimum the weight and overall dimensions make the object easier to store and transport.
Product History
The use of the collapsible umbrella dates back to the 1st century A.D. According to wikipedia, “the oldest reference to a collapsible umbrella dates to the year 21 A.D.” (4) The collapsible umbrella is said to have been designed in China “for a ceremonial four-wheeled carriage” under the rule of Wang Mang. Over the years the collapsible umbrella received significant redesigns, each of which helped create the common design present in contemporary collapsible umbrellas. One notable redesign was the incorporation of a telescoping frame, credited to Hans Haupt of Berlin (5). Haupt’s initial purpose for the telescoping umbrella was to have it function as a cane and an umbrella. The telescoping frame allowed him to carry both around at a size that fit into his pocket. Another notable redesign was the incorporation of new materials such as cotton, plastic film, and nylon to replace original silk.
Product Functionality and Use
To open the umbrella, the user presses the button on the handle and allows it to extend and then expand fully. Then he or she holds the umbrella over her or his head, so as to prevent the elements from reaching her or him. To close the umbrella, the user pulls the rider down until it is locked back into the handle.
Mechanical Function
The mechanical function of the umbrella consists of two portions: (1) Opening the umbrella and (2) Closing the umbrella. There are specialized terms used in this description. Please refer to the relevant drawings for a better understanding of what the specialized terms are referring to. The specialized terms are placed within quotations.
Opening the Umbrella:
To open the umbrella, the release button is pushed (refer to Figure 2). This causes protrusion A to move out of Hole A. As a result, the rider is free to move away from the base. The rider moves away from the base and moves upwards because it is attached to the top rod via linkages 4 and 21 of Figure 2. The “top rod” is attached to the “upper spring,” which is attached to the “middle rod.” The “middle rod” is attached to the “lower spring,” which is attached to the “bottom rod.” As a result, the “rider” springs upwards away from the handle. Because the springs and rods are all interconnected, the whole telescoping mechanism also springs into its full length. During this, the “flatside-down rider latches” spring out to secure the telescoping mechanism and prevent it from recompression. The “flatside-up rider latch” also springs out but for a different purpose. This latch prevents the “rider” from leaving its terminal position.
During the extension of the telescoping mechanism, there is also another mechanism at work: “the umbrella arm mechanism.” The umbrella arm mechanism is divided into two sections. The umbrella is also folded into these two sections. As a result, the two sections have the length of umbrella when it is closed up. Specifically what happens is the following: As the “rider” moves up, “angle α” decreases which causes “section 1” to extend into the positive x direction. Component “5” pushes section 2 out but not as much as “section 1,” resulting in “section 2” extending outwards into the positive x direction also. The combined effort of all the arms extending the positive x (or positive r direction, radially) causes the umbrella to open up.
Note: The arms on our umbrella does not have component “61” and “62” that is shown in the diagram.
Closing the Umbrella:
When closing up, the user needs to push in the “flatside-up rider latch” to free the “rider” from being secured. Then user then needs to pull the “rider” towards the handle. This will require force since the user is going against the compressive force of the spring. As the umbrella moves down the three rods of the telescoping mechanism, it engages with the curved side of the “flatside-down rider latches.” This pushes the “flatside-down rider latches” inward and frees the rods of the telescoping mechanism. This allows the umbrella to be retracted. When the “rider” moves down into the handle, it locks with “protrusion A” and remains there in the closed state. On the other hand, “the umbrella arm mechanism” does the same thing as it does when “opening the umbrella” except it is in reverse.
Bill of Materials
Assembly List
Parts List
Part Number | Name | Quantity | Mass, g | Function | Material | Manufacturing Process | Image |
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01 | Elastic Rope | 1 | 3 | Provides a convenient mode of carrying the umbrella when not in use | Rubber + Polyester | Cut from source rope and tied into loop shape | |
02 | Rope Clip | 1 | < 1 | Clips over tied end of elastic rope handle (part #01) to prevent fraying. Also the sight of brand logo | Plastic | Injection Molding | |
03 | Handle Mechanism Casing | 1 | 38 | To house release mechanism. Added weight and rigidity of clear cylindrical block enhances stability and strength | Plastic | Injection Molding | |
04 | Screw | 1 | < 1 | Attaches handle casing (03) to the anchor (05) and to the telescoping rod (08) | Steel | Subtraction & Deformation | |
05 | Anchor | 1 | 4 | Houses release button (06) and handle spring (25). The rod of the umbrella (08) fits into a slot at the bottom of this part. A small notch at the top of this component keeps the release button (06) and rider (07) in proper alignment. A hole near bottom of component is location where the screw (04) attaches this component to the handle mechanism casing (03) and also to the rod. | Plastic | Injection Molding | |
06 | Release Button | 1 | 4 | Releases latch inside handle to allow rod extension | Plastic | Injection Molding | |
07 | Rider | 1 | 11 | Once pushed upward by user, activates arm mechanism | Acrylic | Injection Molding | |
08 | Telescoping Rod and Spring | 1 | 46 | Holds the umbrella in place. A spring inside this set of concentric tubes allows umbrella to expand and contract. | Steel | [Insert Manufacturing process] | |
09 | Supporting Rider | 1 | 4 | Serves as an additional location to anchor struts (08) (instead of fastening them to the rider along with component 17. | Plastic | Injection Molding | |
10 | Supporting Ring 1 | 2 | <1 | Fastens struts (18) to supporting rider (09). Fastens wire connector A to rider (08) | Aluminum | Metal Deformation | |
11 | External Upper Spring | 1 | 20 | Adds elastic potential energy to compress and release the umbrella. It allows it to contract and expand. | Steel | Deformation | |
12 | Top Notch | 1 | 3 | With the help of supporting ring 2 (13), attaches vane A (16) to the top of the telescoping rod (08) | Plastic | Injection Molding | |
13 | Supporting Ring 2 | 1 | <1 | Fastens Vane A (18) to the top notch (12). | Aluminum | Metal Deformation | |
14 | Pin | 1 | <1 | Attaches top notch (12) to top of telescoping rod (08) | Steel | Subtraction | |
15 | End Cap | 1 | <1 | Seals top end of telescoping rod. Also serves as site of brand logo. | Plastic | Injection Molding | |
16 | Vane A | 8 | <1 | Connects top notch (12) to (22). Acts as part of the first four-bar linkage | Aluminum | Stamping & Deformation | |
17 | Wire Connector A | 8 | <1 | Joins the rider (07) to the strut (18) | Aluminum | Deformation | |
18 | Strut | 8 | <1 | Connects supporting rider to vain. Acts as part of the first four-bar linkage | Aluminum | Stamping & Deformation | |
19 | Link | 8 | <1 | Acts as part of the first four-bar linkage. | Aluminum | Stamping & Deformation | |
20 | Linking Staple | 8 | <1 | Provides a platform for connecting wire 434523423 to link 435342664 | Aluminum | Deformation | |
21 | Wire Connector B | 8 | <1 | Part of second four-bar linkage | Aluminum | Deformation | |
22 | Vane B | 8 | <1 | Acts as second four-bar linkage | Aluminum | Stamping & Deformation | |
23 | Butterfly Connector | 8 | <1 | Joins wire connector B (21), Vane B (22), and rib (24). Acts as part of second four-bar linkage. The cloth (26) is attached to this component via string | Aluminum | Stamping & Deformation | |
24 | Rib | 8 | <1 | Provides additional length for the canopy arm. The cloth (26) is attaches to this component via string | Plastic | Injection Molding | |
25 | Internal Spring | 1 | 4 | [Insert function] | Steel | Deformation | |
26 | Cloth | 1 | 60 | Shields user from the elements | Polyester | Sewing |
Analysis
Detailed Product Analysis
Design for Manufacturing & Assembly (DFMA)
Manufacturing
Guideline | Good Design Choices | Areas for Improvement |
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Minimize Part Count: Eliminate fasteners, part consolidation |
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Standardize Components: Take advantage of economies of scale & known component properties | ||
Commonize Product Line: Economies of scale and minimum training and equipment |
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Standardize Design Features: Common dimensions for fewer tools and setups |
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Keep Designs Simple: simplest way to achieve needed functionality |
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Multifunctional Parts: |
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Ease of Fabrication: Choose materials easy to work with |
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Avoid Tight Tolerances: Causes exponential cost increases |
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Minimize Secondary & Finishing Only where needed |
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Taking Advantage of Special Process Properties: | ||
Other: |
Assembly
Guideline | Good Design Choices | Areas for Improvement |
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Minimize Part Count: Eliminate unnecessary parts | None
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Minimize Assembly Surfaces: and sequence them | None
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Use Subassemblies: Can be assembled and tested separately, can be outsource |
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Mistake-proof: unambiguous, unique assembly orientation |
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Minimize Fasteners: snap fits and part consolidation |
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Minimize Handling: Position for insertion or joining is easy to achieve | ||
Minimize Assembly Direction: ideal is to add each component from top to base | ||
Provide Unobstructed Access: Consider assembly path | ||
Maximize Assembly Compliance: chamfers and radii help assemble parts with variance | ||
Features that have no functionality but support assembly: | ||
Other: |
Failure Mode Effects and Analysis (FMEA)
The two main issues that need to be dealt with in FMEA are:
- Plasticity of the rib and the umbrella arms (stretchers):
Wind and other external factors cause the umbrella to change shape or flips over. It’s important that a proper load analysis is done so that the 4-link joints that make up the stretcher as well as the arms that make up the rib of the umbrella have room for deformation before the umbrella gives in.
- Fabric Quality:
The quality of the cloth used must be checked and undergo quality assurance before it is manufactured along with the other parts. It is important that the right fabric is used and that the coating and finish provided by the fabric supplier is appropriately applied.
Item and Function | Failure Mode | Effects of Failure | S | Cause of Failure | O | Design Controls | D | RP N | Recommended Actions |
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Handle with release button | Jamming | Umbrella does not open | 4 |
| 3 | Unknown | 1 | 12 | Rubber around button to seal finger from debris |
Telescoping stem |
| User could be harmed or the umbrella may not open | 6 |
| 3 | Bending Geometry | 1 | 18 | Detailed Stress Analysis |
Shaft | Splintering | [Umbrella becomes un-useable | 7 | Excessive loading on shaft | 4 |
| 6 | 168 |
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Connecting wire | Snaps | Arms detach from shaft | 5 | Wear and tear | 3 |
| 5 | 75 | Material Selection |
Stretcher | Plasticity | Umbrella flips over/ deforms in shape | 6 |
| 6 |
| [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
[Item and Function] | [Failure Mode] | [Effects of Failure] | [S] | [Cause of Failure] | [O] | [Design Controls] | [D] | [RP N] | [Recommended Actions] |
Design for Environment (DFE)
Due to the multiple ways that Umbrellas can made including sheet metal, wood, fiberglass, the Design for Environment Analysis was based solely on the the product we dissected for Phase 1. The sectors included cover the major components of the umbrella. That includes plastic manufacturing, metal manufacturing, spring manufacturing, and cloth fabrication. The analysis is based off of the Carnegie Mellon Green Institue tool: eiolca.net. The following table represents the results obtained.
Plastic Component Manufacturing | Aluminum Component Manufacturing | Fastener/Screw Component Manufacturing | Spring Component Manufacturing | Fabric Component Manufacturing | |
Item | Plastic Components | Neck and Arms | Fasteners and Screws | Springs | Waterproof Fabric |
Sector | #32619A: Other plastics product manufacturing | #33211B: Crown, closure and metal stamping manufacturing | #332720: Turned product and screw, nut, and bolt manufacturing | #332600: Spring and wire product manufacturing | #313310: Textile and fabric finishing mills |
Cost Per Unit | $2 | $10 | $0.50 | $1 | $2 |
Lifetime Unit | $2 | $10 | $0.50 | $1 | $2 |
Sector mtCO2e per $1M | 904 | 1030 | 707 | 926 | 1130 |
Implied mtCO2e per product life | 0.001808 | 0.0103 | 3.535E-4 | 9.26E-4 | 0.00226 |
CO2e Tax @ $30/mtCO2e | $0.05424 | $0.309 | $0.010605 | $0.02778 | $0.0678 |
- The end of life is not considered in the EIO-LCA analysis*
Assumptions were made regarding the price distribution of each component based on amount of material used and manufacturing complexity. In addition this follows the assumption that each user has one umbrella per lifetime. Under normal circumstances this number may change with unforeseen circumstances such as improper use or calamity.
Following the data above, it is seen that the only greenhouse gas emission created is during the manufacturing of the umbrella components, as regular use does not involve any additional consumptions such as electrical use (batteries). Within the total manufacturing process, the aluminum production required for the body/shell of the umbrella produces the most greenhouse gases. While its sector [Crown, closure and metal stamping manufacturing] does not produce the largest amount of Greenhouse gases when evaluating the output per $1Million, the amount of material used in the umbrella is much greater than any other sector, resulting in 2/3 of the overall output.
To summarize, the umbrella can be separated into 5 separate sectors of the industry, with the largest sector contributing 66% (Aluminum). The overall tax placed on the greenhouse gas emmision (rounded up) per umbrella is $0.49, a small 3% of the total $15.50 price.
Team Member Roles
Lizmarie Comenencia Ortiz: Team Leader
Conroy Brown: Creative Design Practicality Leader
David Carter: DFMA Leader
Dennis Ou: Outreach and Development Leader
Teja Shah: FMA Leader
Marcus Townsend: DFE Leader
References
1. Carnegie Mellon University Green Design Institute. (2012) Economic Input-Output Life Cycle Assessment (EIO-LCA) US 2002 (428) model [Internet], Available from: <http://www.eiolca.net/> [Accessed 15 September, 2012]
2. Dieter, George E., and Linda C. Schmidt. Engineering Design. 4th Edition. New York, NY: McGraw-Hill, 2009. 707-715. Print.
3. http://en.wikipedia.org/wiki/File:Parts_of_an_Umbrella.svg