Andrew Yuan, Fred Shen, Ishi Singh, Timothy Yang, Duke University
People with hemiplegia, or motor weakness on one side of the body, often have difficulty cooking and using common kitchen appliances. The goal of this project is to build or modify kitchen aids that can be used with one hand. Six different devices were constructed to satisfy major areas of need for the client: adaptive handles, an adjustable platform for falling cans after automatic can opener usage, a jar opener, a modified cutting board, a pot stabilizer, and an adjustable electric cart. Using these devices, the client can independently prepare, cook, and serve a complete meal from start to finish.
Our client has hemiplegic cerebral palsy and only has complete motor function on the right side of her body. She has a passion for cooking, but has difficulty accomplishing kitchen tasks with her condition. The goal of this project is to create multiple devices that can be adapted to the client’s appliances, making them easier to use with one hand. Providing the client with the ability to cook independently would increase the quality of her life by allowing her to pursue her culinary interests.
Our client struggles with lifting/moving heavy objects and keeping objects in place. Six different areas of need were identified in our client’s kitchen: moving plastic containers to and from an overhead microwave, not spilling cans as they fall from an electric can opener, opening jars and bottles, cutting different foods stably, holding pots in place while stirring, and lifting casserole dishes from the oven to the counter. The goal of our project is to create multiple devices that will meet these needs and allow our client to cook independently.
DESIGN AND DEVELOPMENT
Microwaveable Container Handle
The Can Catcher is composed of a base, 4 posts, and an adjustable platform which are all made from rounded high-density polyethylene (HDPE) as well as 8 stainless steel pegs. The four posts are fastened to the base with polycarbonate machine screws. An adhesive, Loctite 406, was used to prevent rotation of the posts. Two stainless steel pegs protrude from each post. They are placed at two levels, positioned to accommodate the two main types of cans our client uses(tuna cans and soup cans). The adjustable platform is a piece of HDPE with grooves milled into the underside so it can rest on the stainless steel pegs without slipping.
The Can Catcher is composed of a base, 4 posts, and an adjustable platform which are all made from rounded high-density polyethylene (HDPE) as well as 8 stainless steel pegs.The four posts are fastened to the base with adhesive and polycarbonate machine screws. An adhesive, Loctite 406, was used to prevent rotation of the posts. Two stainless steel pegs protrude from each post. They are placed at two levels, positioned to accommodate the two main types of cans our client uses (tuna cans and soup cans). The adjustable platform is a piece of HDPE with grooves milled into the underside so it can rest on the stainless steel pegs without slipping.
The Jar Opener is comprised of a base and two raised walls oriented in a V-shape which are both made from HDPE. This design is based off of a commercial product, the SoloGrip. (1) The walls are fastened to the base with polycarbonate screws. Dycem rubber is glued with Loctite 406 onto the insides of the two walls and form feet that stabilize the base. The jar or bottle is placed between the walls until held securely by the Dycem rubber. The lid can then be twisted off with a single hand. The V-shape accommodates many different sized jars or bottles.
Our client already owned a Swedish Cutting Board meant to facilitate easy cutting, but she didn’t like the spikes that were used to hold ingredients in place. (2) In contrast, the cutting board we designed uses twelve adjustable stainless steel pegs and irregularly spaced holes to accommodate differently size ingredients. The entire body is constructed from rounded HDPE. A long divider separates the meats side from the fruits/vegetables side. Two small raised walls in the bottom left corner form the bread holder. This design was inspired by an existing product, the Spreadboard. (3) The divider and walls are screwed into the body with polycarbonate screws. A oval-shaped slot on one end forms a handle. Four Dycem rubber feet on the bottom hold the cutting board in place during operation.
Our client already owned commercial pot holders. However, the rubber suction cups did not work well and our client complained they were too small for her pots. (4) We created a new design that would fit different pot sizes and was more stable than her commercial product. All components of the Pot Stabilizer are connected to the square, aluminum base. On the bottom are silicon rubber pads which are attached with Loctite 406 glue. The two posts are each made of three aluminum blocks that are welded together. They can either hold a long panhandle in between the posts or hold the “ears” of a pot by hooking the posts through the grip of the handle. A handle, made of two stainless steel cylinders which are permanently connected to the base with an internal bolt, also serves as a weight to provide stability.
The Casserole Cart is comprised of a battery pack, a car jack, four drawer slides, four casters, a top with ramp, a handle, two metal cross rods, a jack support, two sets of scissor legs, top and bottom frames, and two wooden cross supports.
The Husky 300-Amp Portable Jump Starter provides power to the car jack when turned on with a switch and is controlled with a wired controller. The wires have been extended by cutting the original wire and inserting a longer piece in between. Heat shrink carefully covers the soldered parts to prevent electrical shock. The controller is placed beneath the handle for convenient access and is attached by two zip ties. The wires have been tied to the frame by zip ties as well to prevent them from dangling and hooking onto external objects.
The BLACK BULL 2000 lb. 12-Volt Electric Car Jack is used to change the height of the cart and is powered by the battery pack. The jack is attached to the front of the base frame, and is connected to the adjustable scissor mechanism through the jack support. It is operated by an up-down controller that is attached to the side of the cart for easy access. The adjustable range of the jack corresponds with the desired height of the cart. Our prototype used a manual crank for adjusting height. We chose to use an electric car jack instead because our client asked that make the cart easier for her to operate.
Sugatsune drawer slides are mounted to the top and bottom frames and connected to the cross rod to provide mobility to the scissor legs. They are also greased with WD40 to reduce friction and increase smooth motion.
The casters are attached to the corners of the bottom frame, allowing the cart to move between the kitchen and the dining room. Each has a locking mechanism, stabilizing the cart when objects are being transferred to and from the cart top.
Top with Ramp:
The cart top and ramp are made of plywood. Both are spray painted with high temperature resistant black paint (resistant up to 1200 degrees Fahrenheit). The cart top is screwed to the top frame.
The Threshold(TM) Towel Bar is attached to the cart top with wood screws to serve as a handle.
Metal Cross Rods:
The two metal rods connect the scissor legs to the drawer slides, allowing for smooth rotation of the legs and providing structural support to the cart.
The jack support piece is made of aluminum tubing with two posts. The posts connect to the metal cross rod, transferring the motion of the jack onto the cross rod to operate the scissor legs. The jack support is reinforced with corner braces and a bungee cord to provide rigidity and stability.
The scissor legs are attached to the metal cross rods at one end and to shoulder bolts at the other end. Each set of legs is connected with another shoulder bolt at its midpoint. The scissor legs allow for the cart to change height with horizontal movement of the car jack.
Top and Bottom Frame with Stop Posts:
The top and bottom frames are rectangular and made of aluminum tubing. The short sides of each frame have sidewalls where the drawer slides mount. In addition, the bottom frame has sidewalls that are outfitted with stop-posts to prevent the cart from going below the specific height and obstruct the oven door during usage.
Wooden Cross Supports:
The wooden cross supports are made of hardwood, and are attached to the top and bottom drawer slides. The supports prevent wobbling of the cart by forcing the drawer slides to move in unison.
The car jack is operated by an electrical schematic where the battery pack provides voltage to the car jack. When the switch is turned one way the height increases; reversing the polarity decreases height.
The replacement costs for all the devices are as follows: $66 for the three microwaveable container handles, $13 for the can catcher, $46 for the jar opener, $36 for the cutting board, $8 for the pot stabilizer, and $294 for the casserole cart.
We successfully constructed all six devices and performed quantitative testing to make sure they met our performance specifications. The height range of the casserole cart extends from 21’’ to 36.5’’ as desired. It takes approximately 60 seconds to move through the full range of height, and can withstand up to 20 lbs without failure. The can catcher is adjustable height and works successfully with both 4.5’’ and 1.5’’ cans. It can withstand up to 3 lbs without failure. The microwavable container handle successfully withstands temperatures up to 100 degrees Celsius for 10 minutes. We tested it by boiling water in it for 20 minutes and observed no leakage or change in physical state. The microwavable container handle also has a maximum operational load equal to the weight of the container filled with water. It safely withstands twice the maximum operational load. The client testing of the jar opener, cutting board, and pot stabilizer proved sufficient to determine their performance.
DISCUSSION AND CONCLUSIONS
In conclusion, we successfully created six devices to address our client’s needs. With our devices she is now able to easily lift food containers to and from her microwave, use her automatic can opener without fear of spilling the cans, open jars and bottles quickly with one hand, cut and prepare food, stir pots and pans without them rotating, and finally cook large casserole dishes. Through quantitative evaluations and client testing we proved that our devices were viable and effective. Our design choices were motivated by our client’s input and we were able to provide alternative solutions to devices she already owned. Our client’s therapist stated in the feedback survey that these “projects [will] make [our client’s] cooking experience better.” Our team also visited our client this spring. A couple of months after delivering the devices, she was still using them and said they increased her independence and “made [her] life easier.” We were glad to see our long days and late nights of work come to fruition. Above all, we were honored by the chance to improve our client’s quality of life by helping her to pursue her passion for cooking.
We would like to thank our instructor, Dr. Laurence Bohs, Costi Shami, Steve Earp, Greg Bumpass, our Advisory Board members, and our client and her physical therapist, Dr. Thorpe, for their input and support throughout the semester.
3040 Crest Dr
Clearwater, FL 33759
(1) The Wright Stuff, Inc. SoloGrip One-Handed Jar Opener. Amazon. Retrieved from http://www.amazon.com/The-Wright-Stuff-SoloGrip-One-Handed/dp/B000G39ZWA
(2) North Coast Medical. Swedish Cutting Board. Amazon. Web. 17 Sept. 2013. Retrieved from http://www.amazon.com/The-Wright-Stuff-Swedish-Cutting/dp/B000HZU06C
(3) Bread Spreading Board. Essential Aids. Retrieved from <http://www.essentialaids.com/kitchen-aids-feeding-aids/utensils/bread-spreading-board.html>
(4) The Wright Stuff, Inc. Pan Holder. The Wright Stuff. Web. 17 Sept. 2013. Retrieved from http://www.wrightstuff.biz/panholder.html