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Team Members: Michael Apone, Collin Issel, Joseph Longville, Jackson Striggow
Team Members: Michael Apone, Collin Issel, Joseph Longville, Jackson Striggow
Project Sponsor(s): Ms. Nancy Cowles, Kids in Danger Organization
Project Sponsor(s): Ms. Nancy Cowles, Kids in Danger Organization
Project Description:
Project Description:
Kids in Danger (KID) is an organization dedicated to keeping children safe by advocating for safer products. They participate in the setting of voluntary and mandatory testing standards and performance requirements and have over 10 years experience with evaluating product design for safety and human factors. An important item on KID’s agenda is furniture tip-overs, which involves a large amount of dressers. Every 20 minutes a child visits the emergency room because of a tip-over and yet the current industry standard has not made a dent in these statistics. Although solutions in the form of furniture straps currently exist to make dressers more stable, a majority of parents are not using them because they are either too difficult to install, they don’t want to damage their walls, or they are simply unaware that they exist. As the number of child deaths due to these furniture tip-overs continues to increase, KID has tasked us with designing a dresser for a child’s bedroom that is stable without straps and an anchoring device for present-day dressers that causes minimal damage to walls. Additionally, we have also been tasked with developing testing methods that accurately reflect real life situations when dressers tip. These testing methods should take into consideration dynamic and static forces as well as floor covering, drawer load and child behavior that leads to tip-overs.
Final Dresser Solution
Final Dresser Solution
Our final dresser solution involves transforming the body of the dresser into a unique trapezoidal prism that was determined to be very safe and effective in preventing tip-overs. While a traditional dresser has the center of gravity roughly in the middle of its depth, the unique shape of the trapezoid relocates the center of gravity to the bottom and back of the dresser. With a center of gravity that is closer to the ground and further to the back of the dresser, a furniture tip-over is less likely to occur because it requires much more force to tip the dresser over. Another safety feature we have incorporated into our dresser is a lack of drawer handles which otherwise could be used as climbing points for children. For our dresser, you need to use the slots at the bottom of the drawer to open it. Finally, the top drawer of our dresser has a face that swivels up on a hinge and slides into the dresser. The purpose of the top drawer not being able to be pulled out is because it reduces the number of drawers that a child is able to tug on and climb up. The dresser is made completely of wood with all exterior pieces being composed of birch plywood and all interior drawer frames composed of pine wood. Simulation results showed that our dresser does not tip over until a force of 109 lbs is applied to a drawer in a downwards motion, which would be caused by a child trying to climb the dresser. This result is significant when compared to a recalled IKEA dresser that tipped over at a force of 37 lbs.
The final colorways of the dresser are white, chrysler walnut, and multi-colored:
Final Anchor Solution
Final Anchor Solution
The final anchor solution features a set of two hooked racks with one attached to the wall and the other attached to the back of the dresser. The hooked racks are composed of injection molded ABS (plastic) and they are connected to each other using a set of five nylon bungee cords, one for each hook. The elasticity of the bungee cords help fix alignment issues during installation. In order to ensure that the bungee ropes do not become unhooked, a protective cap comes with the furniture anchor that is snapped onto the hook tips. To install the furniture anchor, each hooked rack has a set of 10 adhesive strips on the back. The adhesive strips do not add any additional thickness to the rack because they are placed in pre-made slots.The adhesive strips are a currently existing product, and each adhesive strip is rated for a load of 5 lbs. Therefore, our furniture anchors are able to support a load of 50 lbs, which is a requirement set forth by ASTM F3096. The first hooked rack is meant to be mounted to the back of the dresser, 1” below the top surface. The second hooked rack is meant to be mounted 7” below that, onto the surface of the wall.
Testing Methods
Testing Methods
For a list of testing method suggestions that accurately reflect real-life situations that cause dressers to tip, we developed a three-phase set of tasks that a company could use to analyze their dressers. The tasks would begin as early as a CAD model is made for the dresser, and they would extend into performing physical testing with the final product. The three phases consist of a theoretical evaluation, a static evaluation, and a dynamic evaluation, where each evaluation is a phase. To begin, a theoretical evaluation is performed by completing a predicted risk test. To perform the predicted risk test, begin by filling out the “Dresser Tip Over Potential” excel sheet with the dimensions of the dresser. The “Dresser Tip Over Potential” excel sheet was created to be a tool that companies could use to assess the stability of their dresser before even building it. The excel sheet requires an input of key dimensions and then it plugs those dimensions into equations from free-body diagrams and determines if your dresser will be expected to tip over. The free-body diagrams consist of 3 different tip-over situations. Inside of the excel sheet are two sheets. The first sheet is titled “Input Dimensions” and the second sheet is titled “Calculations”. Users are expected to begin on the first sheet and input the dimensions of the dresser. Instructions are provided at the top of the sheet that explain how to use the tool. Once the user has inputted the dimensions of their dresser, they can click on the next sheet in the bottom-left corner that is titled “Calculations”. The “Calculations” sheet will output three colored boxes that indicate if your dresser passes the test or not. As stated on the instructions for the sheet, all three boxes must be green in order for the dresser to pass. Using the second sheet, the user must first look at the results that correspond to the height condition of their dresser. A key is available in the top-left corner to describe what each color means. If dresser dimensions were entered and those boxes remained red, the user could refer to the solutions table in the top-right corner for how to redesign their dresser to pass each tip-over situation.
Once the dresser design passes the predicted risk test, you can move onto the static evaluation and perform a static weight test. To perform the static weight test, begin by filling a single drawer with clothes, pulling it to its maximum extension, and then adding a 60 lb weight to the drawer. The 60 lb weight is a desired weight by KID and it more accurately represents an extreme upper limit of a 6 year old child [34]. Keep the other drawers inside of the dresser with no clothes inside of them. Perform this test on carpet. Ensure that the drawer is able to withstand the weight of the load for one minute. Repeat for each drawer. If all the drawers hold the weight successfully, the dresser passes the test.
With a successful completion of the static weight test, you can move onto the dynamic evaluation and perform a dresser pull test. To perform the pull test, attach a rope to the sides of the dresser at a height of 38.75” from the ground or to the top of the dresser if the dresser is shorter than 38.75”. It should be noted that 38.75” is used because it is an upper limit for a 6 year old child’s shoulder height [34]. Attach a force gauge to the free end of the rope and pull on the force gauge until the dresser tips over. Keep all drawers inside of the dresser with no clothes. Perform this test on carpet. In order for the dresser to pass the pull test, the force necessary to tip the dresser should be greater than 55 lbs, which represents an upper limit for a 6 year old child’s pull force [35]. In addition to the dresser pull test, your dresser should also be able to pass a drawer opening test. To perform the drawer opening test, attach a rope to the front of a drawer and attach a force gauge to the other end of the rope. Pull the force gauge from 0 lbs to 55 lbs in a quick burst over a time period less than 0.5 seconds. It should be noted that this force represents an upper limit for a 6 year old child’s pull force [35]. This will dynamically test if a child pulling a drawer quickly will cause the dresser to tip. Perform this test on carpet with no clothes in the drawers. Repeat with each drawer on the dresser. If the dresser remains standing after performing this test on each drawer, then the dresser passes the test.
We believe that by breaking the testing methods up into theoretical, static, and dynamic evaluations, we are able to fully access the tip-over potential at all levels of use. We believe the testing methods are complete, and we believe they accurately reflect real-life situations that cause dressers to tip.
Special Thanks to: Kathleen Sienko, Nancy Cowles, ME 450 Sec 002, Matt Hildner, Jeff Plot
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