Abstract[edit | edit source]
The Smart Cart design project's result is the implementation of a new and improved concession cart for Bernie Levy of Zane middle school. The cart will allow him to more efficiently transport goods and snacks from the cart's storage and loading zone to the outdoor area where kids will purchase such goods.
Background[edit | edit source]
Bernie Levy at Zane Middle School in Eureka has employed our project design project group, The Concession Cart Crew, to solve an issue within the concession cart system that the school currently uses to sell snacks during their daily break. He presented criteria that he expects us to implement into the design of a new concession cart. His main goal is for it to be a dependable and efficient way to transport snacks and goods across the school campus.
Problem statement and criteria[edit | edit source]
Our clients biggest concern for the new cart is the noise level that it will make when being pushed across the campus and past classrooms. Other criteria that our client is concerned about is: handles for easy transportation, the weight of the carts being too heavy for students to push, the strength of the shelves on the cart not being able to withstand the weight of the supplies being sold, reducing the four carts they have now into one or two, creating lips around the shelves so that objects will not fall off, creating cushions on the perimeter of the cart to prevent damaging doorways, and creating a cover for when the carts are being stored.
|Safety||Cannot harm children; nothing sharp or dangerous|
|Noise||Limit sound around classrooms|
|Durability||Must last many years|
|Stability||Keep items from dislodging|
|Efficiency||Minimize number of carts; comfortable handle height|
|Weight Limit||Sturdy enough for all products; light enough for children to push|
|Environmentally Sustainable||Implement up-cycled materials|
|Cost||Must cost less than $300|
Description of final project[edit | edit source]
Here is a full description of the final design decision and process for the concession cart. It will also include the qualitative and quantitative costs in addition to tables representing those values. Installment, use, and maintenance recommendations will be described, followed by the final results through the testing process.
Description of Solution The following describes each aspect of the cart in detail. Figure 2 below is an AutoCAD depiction of our final solution.
Posts/Shelf Material The shelves we reclaimed from the scrapyard are made of old road signs. The larger sign used for the bottom shelf was roughly three feet by two feet. The two signs used for the top shelf are each one foot by one and a half feet. They are connected via the slotted angle posts with screws and washers and supported by a two inch by two inch wooden frame. Figure 3 below illustrate the posts and shelves used in the final design.
Extendable Shelves The extendable shelves are constructed of a thin sheet of plywood attached using a double sided hook and U-Bolt with a non-locking hinge to the bottom shelf and a hanging chain connected to the top shelf; this will be detached during transit. Figure 4 below shows the extendable shelf mechanism.
Storage Area The storage area will provide a space for the merchandise from the extendable shelves when in transit. It will be enclosed with a thin sheet of plywood on three sides. Figure 5 shows the base is made of wire racks and a sheet of plywood.
Wheels The wheels are five inch polyurethane casters. The front two are swivel and the back are non-swivel. This allows easy turning and stable steering when needed. The polyurethane material they are made out of will prevent the noise our client currently has an issue with. Figure 6 shows the difference between swivel and fixed casters.
Cover The cover is made out of a reclaimed bedsheet from a thrift store. Its purpose is to hide the merchandise from the children's view in order to prevent the urge to steal the snacks. The cover will be resized to fit snug around the cart. Figure 7 below shows how the cover fits on the cart.
Rubber Bumper The rubber bumpers are made from upcycled bicycle tires that were reclaimed from a local bicycle shop. They will provide extra protection for the edges and corners of our cart to prevent damages made to the cart itself and to doorways when in transit. Figure 8 shows how the rubber bumpers are attached around the cart.
Handles The handles are from two plastering trowels that have been detached from the metal sheet. The plastic handle remaining is then bolted to the metal post frame between the top and bottom shelf. Figure 9 below shows how the handles are attached to the frame.
Costs[edit | edit source]
The following section describes the qualitative and quantitative costs of the construction of the concession cart.
Design Cost (hours) We have worked at total of 296 hours on this design project for Zane Middle School. The pie chart, shown in Figure 10, illustrates the division of hours for each phase of the project.
Maintenance Cost ($) The expected maintenance cost for this project is minimal. Durability was weighted high on the criteria list for this reason. Since it is used on a daily basis, and by middle school children, we as a group had designed it so it would last many years; this is also why it is being replaced. Because of this, the only maintenance needed would be paint touch ups ($15 a quart), replacing the shelves after years if they show signs of wear ($8 a shelf), and replacing the chain attached to the extendable shelves if were to break ($1 per foot). The maintenance cost in hours is only expected to be around two hours per year.
Implementation Cost ($) The table below indicates the cost of materials that have been purchased for the implementation of the cart. A total of $263.39 has been spent on materials which is below the projected budget of $300.00.
|Quantity||Material||Source||Cost ($)||Total ($)|
|1||Road sign shelf (3'x2')||Arcata Scrapyard||5.45||5.45|
|4||Road sign shelf (1.5'x2')||Scrapyard||2.76||10.90|
|25||Fender washers (1/4)"||Mill Yard||by lb||1.00|
|1||Lumber (2"x4")||Mill Yard||4.76||4.76|
|1||Lumber (2"x2")||Mill Yard||5.60||5.60|
|1||Slot angle post (1.25"x1.25")||Ace||35.00||35.00|
|5||Tire inner tubes||Revolution Bicycle Repair||0.00||Donated|
|10||Metal braces||Almquist Lumber||9.04||9.04|
|19||Metal corner brackets||Almquist Lumber||18.81||18.81|
|3||Spray paint||Almquist Lumber||15.12||15.12|
|1||Paint brush 3"||Airgas||1.60||1.60|
|2||Paint brush 2"||Airgas||2.18||2.18|
|2||Fixed caster 5"||CasterHQ.com||17.32||17.32|
|2||Swivel caster 5"||CasterHQ.com||23.76||23.76|
|1||Double loop chain 5'||Mill Yard||3.16||3.16|
|2||Double hook Snap||Mill Yard||5.18||5.18|
|2||Notch trowel||Mill Yard||4,58||4.58|
Testing Results[edit | edit source]
Upon completing the carts construction, we came across a few unforeseen errors. These technical faults included: an ungrounded wheel; paint that was not willing to dry; sharp, protruding corners; and overly lengthy screws that kept the carts extendable shelves from collapsing completely. To solve the problem regarding the uneven wheel, a quarter inch wooden square was implanted above the problem wheel which let it contact the ground, thus allowing the cart to roll at maximum efficiency. What we originally thought was regular black paint turned out to be an oil based paint that still was not dry a couple days after its application. The solution that we've decided on is to dab up remaining oil paint with cotton balls and then reapply a coat of normal, dry-able paint. As for the sharp corners, we've sanded them a rounder, smoother edge to maximize safety. The most appropriate solution for the extra screw length is to sand down their ends to allow the shelf to fold down parallel to the carts walls.
Discussion of final design and next steps[edit | edit source]
The concession cart is designed to transport snacks and goods across campus in a reliable way. Handles have been implemented into the design to make it efficient for students to push or pull from the storage area to the courtyard where they are to sell the items. In order to make the least amount of trips possible, the cart has been constructed in a way where there are extendable shelves to limit the size while still being able to hold the same amount of stock. While the cart is in motion, the goods will be stored in the bottom and later placed on the shelves the kids will fold up when preparing the cart. A chain will have to be hooked onto the shelf to extend. The cart must be re-stocked with goods as items are purchased. A cover will be placed over the cart to prevent theft from the students.
Team Members[edit | edit source]
References[edit | edit source]
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