Users and Requirements:
Those in power chairs who need a device to transfer groceries from the stores to their kitchens.
Users have six basics needs: structure, ease of use, safety, fit, durability/ maintenance, and other. When thinking about the design of the swivel shopper and implementing the ideas into mock ups, having satisfactory performance in all aspects of the user needs and wants was a primary objective.
Users need a way to carry an average of 4 grocery bags or 10 pounds without harming the groceries. The users desire independence and a free range of motion while still keeping their purchases safe from theft and damage. Additionally, users should feel safe from physical harm while transporting groceries. The device should be able to endure a range of weather conditions and should be easy to clean. Users also need an aesthetically appealing solution that does not draw attention to the user.
Final Product
Swivel Shopper when it is fully collapsed:
One of the features we wanted to include in the Swivel Shopper was it to be easily stored. Here, you can see that when it is fully collapsed, it is thinner than an average back pack so the user can store it underneath a bed, in a corner, or between shelves.
Alpha Prototype:
The Swivel Shopper clamps to the armrest of a power chair and holds groceries in a wire frame basket attached with pegs to a swiveling arm. As shown in Figure 1, it consists of a basket, a swivel action arm, a tent pole slide extender, and a stabilizing outrigger with a belt attachment. The Swivel Shopper can be customized to accommodate wheelchairs and users of multiple sizes through the tent pole slide extender that allows the user to push or pull the box to an optimal distance. The swivel mechanism allows users to choose between keeping the box in front of their bodies or to push the box farther out in front of the wheelchair, so the user can move or leave the chair. The swivel shopper’s total weight is 6 lbs.
Collapsible Basket and Y-bar:
The basket is 13” wide, 8.5” tall, and 8.5” deep. It is bicycle basket composed of a plastic covered steel wire frame. There are cut outs on both sides of the basket that face the user. Elastic netting covers the cutouts. The bottom is slanted towards the tent pole slide extender. The bottom folds upward, and the sides fold inward into the basket, so the basket can collapse. Supporting the bottom of the basket is a Y shaped aluminum bar that is .25” thick. Grooves on the bottom of the basket slide into railings on the Y-bar. The branches of the Y-bar are 5.5” long and 1.375” wide. The central arm of the Y-bar that connects to the swivel is 1.5” wide and 9” long. When the tent pole slide extender is fully extended, the basket can hold up to 12 lbs. before the basket sags more than 2”. With the extender completely pushed in, the basket can hold up to 8 lbs. (Maximum weights were measured with armrests 10” long, the average of observed armrest lengths).
Swivel Action Arm:
The end of the inner bar of the tent pole slide extender meets the end of the Y-bar at a pin. A metal disk with a 2” radius lies on the pin between the two bars in order to provide support and torque control. Because the pin allows motion, the two bars can swivel around each other parallel to the ground, allowing the user to swivel the box around a point at the end of the armrest.
Tent Pole Extension:
The tent pole slide extender, as shown in Figure 4, consists of a 18.75” long, .25” thick, 1” wide aluminum bar nested inside of a 18.75” long, .75” thick, 1.5” wide rectangular aluminum tube with ?” thick walls. Four long strips of adhesive cork line the inside corners of the outer tubing to absorb shock and allow the bar to slide within the tube. There is one hole with diameter .5” drilled vertically in the outer tube, and there are seven holes with diameter .5” drilled vertically, evenly spaced at 1” intervals in the inner bar. A movable pin can be inserted through any hole in the outer tube and through the hole in the inner bar. This keeps the tent pole slide mechanism in place once the user decides where the box should be. Fully extended, the Swivel Shopper is a total of 30” long, and completely pushed in, it is 24” long.
Outrigger and Clamps:
An outrigger that acts as a stabilizing element hangs vertically along the side of the wheelchair as shown in Figure 6. The element consists of a 12” long, 1.00” by 1.50” rectangular aluminum tube that hangs vertically from the side of the outer bar, attaching with a pin that allows the stabilizing element to swivel perpendicularly to the ground. A 2” wide, 6’' long nylon strap and easy-to-adjust flip buckle loops around the bar and attaches with a belt buckle to the opposite arm of the wheelchair. The user sits on this strap to offer torque control. A double-plated clamp holds the horizontal bar against the armrest, with one plate of the clamp on top of the horizontal bar and one plate of the clamp underneath the armrest. The top plate of the clamp is .125” thick, 5.75” wide, and 2” deep. The bottom plates are each .125” thick, 2.75” wide, and 2” deep. There is a .5” wide gap between the plates.
Assembly
Materials
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Swivel Shopper
Problem
Power chair users have very little room to transport their grocery bags from the store to their homes. Current solutions restrict user mobility through doorways, harm their groceries, and make their groceries vulnerable to theft.
Purpose
Our team’s goal was to design a universal product that would allow the residents of Eden Supportive Living who use power chairs to buy and transport groceries independently and safely.
Methodology
Power chair users were interviewed and observed while traveling from Eden Supportive Living to the local Jewel Osco and back. Grocery aisles and check lines were simulated for performance testing. User testing was conducted at Eden with multiple residents.
Design
The Swivel Shopper stores groceries in basket on a swiveling arm that attaches to most power chairs.
Limitations
Our design cannot carry over 12 lbs without slanting. Furthermore, it does take an average of a full minute to attach to the power chair on average.
