Executive Summary

Problem Statement

Michelle Urban of Shriners Children’s Chicago presented us with the multiple difficulties she is experiencing with the halo traction walkers and wheelchairs the hospital is currently using. One of the main issues mentioned was the weight imbalance on the wheelchairs they use due to the additional weight of the halo traction equipment on the back of the device.

Purpose and Scope of Project

The purpose of this project is to prevent wheelchairs from tipping by developing a modular clamp with an adjustable nut-bolt system that allows for varying height adjustments.

Design Methodology

This design was developed following multiple interviews with Michelle and a complete assessment of the different problems that could be addressed. In-person user performance and user testing was also performed, and our mockups and final design were tested on a variety of different wheelchair makes and models. 

Design Summary and Benefits

Our final design features a 3D-printed clamp that fits around the bottom frame of a wheelchair. The height adjustment mechanism features a ⅞” Nut and bolt, which is welded onto the top of the steel frame of the 3”-tall rubber caster wheel. The 3D-printed clamp has a horizontal protrusion that houses the bolt, enabling it to move up and down only. The clamp will be connected to the frame of the wheelchair via ¼” screws. The cutout of the hole within the roof and underside of the clamp is ovular. This ovular shape enables the clamp to fit around varying sizes of steel frames that the wheelchairs may be constructed with. Since the radius of the ovular cutout is ~1.5 larger than the radius of standard frames, it will be able to still clamp around the frame, regardless of whether the size is a perfect fit. When attached to the halo-traction wheelchair, the finalized design should operate in a manner similar to that of a training wheel on a bicycle. Utilizing the adjustable screws on both the clamp and wheel, the wheel should maintain a parallel position to the existing larger wheelchair wheels and sit perfectly on the ground with little to no room for upward or downward movement. In addition, the clamp, which is connected to the silver rods near the rear of the wheelchair, should fit tightly and securely, with little room available for possible movement. The addition of a smaller support wheel restricts the tipping of the halo-traction device and wheelchair as the weight is more effectively distributed throughout the back of the device through multiple contact points with the floor. 

Mission Statement

Throughout this quarter, we designed a solution to help our project partner, Shriner’s Childrens Hospital, maintain and manage their halo traction equipment for both walkers and wheelchairs. We worked together as a team, with constant communication and feedback from our project partner to identify and create the best solution for this problem by utilizing the design process. 

We wished to improve the user experience, including both the safety and durability of the halo traction device; we stabilized the weight distribution of the device through the addition of smaller, stabilizing wheels, to the original back wheels of the wheelchair and walkers. 

Project Partner Information

Michelle Urban, Shriners Childrens’ Hospital

Ms. Michelle Urban, a physical therapist and clinical supervisor at Shriners Children’s Chicago, presented the design problem. While there are multiple facets of the problem that Shriners Children’s experiences with their halo traction equipment, the main issues relate to a specific clamp that is used on all models of the equipment that they currently use. The clamp is no longer manufactured, and it does not correctly fit all of the walkers and wheelchairs that they currently use. In addition, after repeated attachments and removals, the screws on the clamp become worn and become stripped of their material. Another primary issue that may be considered is the imbalance of weight distribution throughout the walkers, which present safety issues, as well as difficulty of use, while patients use the devices.

Future Design Development

The primary area of improvement that could be made upon this design is the material used to connect the ⅞” bolt to the caster wheel. In this design, a polycarbonate sheet was used to connect these two items together, but future designs may consider using a stronger material such as metal, or even welding the bolt directly to the wheel plate, if equipment allows. 

Team

Special Thanks