CHAPTER 11 UNIVERSITY OF FLORIDA College of Engineering Department of Aerospace Engineering, Mechanics, and Engineering Science Gainesville, Florida 32611-6250 Principle Investigator: Robert 1. Hi&o (904) 392-6104 167
168 NSF 1995 Engineering Senior Design Projects to Aid the Disabled One-Arm Wheelchair Control System Designers: Mark Dallara Supervising ProJesor: Roberf J. Hirko Ph.D., Ali A. Seireg Ph.D. Aerospace Engineering, Mechanics, and Engineering Science University @Florida Gainesville, FL 32611-6250 INTRODUCTION Propelling a non-electric wheelchair is typically a two-handed effort, especially when straight-line motion is involved. This presents a problem to wheelchair users with functional use of only one hand. Alfred, 76, suffered a stroke 15 years ago that left him partially paralyzed on the left side of his body. He can walk short distances with the aid of a quad-cane, but uses a wheelchair frequently indoors and outdoors. Using a normal wheelchair poses problems, from moving away from the kitchen table to maneuvering across the living room. The One-Arm Wheelchair is designed to allow Alfred to move the wheelchair in a straight line with one hand, but also allow turning motion when necessary. A lightweight wheelchair is modified by the addition of an aluminum torque-transfer mechanism that contacts the wheels of the chair with two small rubber wheels. A handle next to the right armrest allows the patient to engage the mechanism for straight-line movement, or disengage the mechanism for turning. The device separates and folds out of the way when the chair is collapsed. The chair with control lever and one drive wheel is shown in Figure 11.l. SUMMARY OF IMPACT The wheelchair is intended primarily for indoor use, but also for occasional outdoor use. The following design criteria are established for the chair:. a lightweight mechanism design which does not interfere with collapsibility of the chair. straight line and turning movements enabled when required These criteria are accomplished and it did not take long for Alfred to learn how to manipulate the devices. The overall benefit seen from this chair is that Figure 11.I. Chair for One-Arm Operation. Alfred has a much greater degree of control over his position while he is in the wheelchair. The chair and modifications collapse to fit into the tnmk of a car when needed for outdoor use. Propulsion by a second individual is not impeded by the mechanism, so the device may remain in its unfolded state when the chair is not being moved by the occupant. TECHNICAL DESCRIPTION A pair of formed aluminum bars comprise the supports for the device. They are attached to the seat handlebars at the top, and to blocks clamped onto the wheelchair frame at the bottom, as seen in Figure 11.2. The right-hand support is directly connected to a bearing housing which may be rotated slightly to engage or disengage the rubber wheel on the right. Another aluminum bar connects the right side of the bearing housing and to an over-the-center lock on the block clamped below (Figure 11.3). This lock is controlled by a handlebar that the chair occupant moves to engage the wheel as is demonstrated in Figure 11.l. The torque transfer system consists of rubber wheels
Chanter 11: Universitv of Florida 169 attached to aluminum rods in bearings, with hexagonal sockets and a section of hexagonal rod between the two halves of the transfer. They can be seen disconnected in Figure 11.2 and connected in Figure 11.3. By pulling back slightly on the pins set into the hexagonal bar, the left side of the transfer may be disconnected and rotated so that it is parallel with the seat back bar of the wheelchair frame, and thus out of the way. When the mechanism is disconnected in this manner, the chair may be collapsed in the normal fashion for transportation. Figure 1 1.3. Drive Assembly. Figure 11.2. Rear View of Mechanism, disconnected.
170 NSF 1995 Engineering Senior Design Projects to Aid the Disabled RETRACTABLE FOOT SUPPORTS FOR A SHOWER CHAIR Designer: Elizabeth C. Phillips Client Coordinator: Mark Frasier, Sunland at Gainesville Supervising Pr@ssor: Robert J. Hirko, Ph.D. Aerospace Engineering, Mechanics, and Engineering Scieme University @Florida Gainesville, FL 3261 l-6250 INTRODUCTION For individuals requiring full-time use of wheelchairs, bathing and personal grooming can be a difficult challenge. Shower/toilet chairs are used for this reason. The problem with these types of chairs is that they have no place for individuals to place their feet. Consequently, some individuals may tend to straighten their legs in a rigid posture making attendant care nearly impossible. The purpose of this project is to provide foot supports that are able to withstand repetitive loading and also be resistant to exposure to moist environments. The supports should also retract so that they do not interfere with transport to and from the shower chair and wheelchairs. SUMMARY OF IMPACT A local care facility for severely developmentally disabled individuals supplied the chair for modification. As can be seen in Figure 11.4, the foot rests are easily bolted on to the frame at the front wheel positions. This chair became a great aid to attendants at the facility for transport to, from, and in the shower. Making care giving easier as a natural result also made more care available to those who needed it in the facility, since caregivers are less reluctant to attempt showering the clients. Figure 11.4. Foot Supports on Toilet Chair
Chapter 11: University of Florida 171 TECHNICAL DESCRIPTION Each foot support consists of a three-piece mounting block, a rotating arm, and a 90-degree rotating food plate taken from a wheelchair. The mounting block is fitted to a currently used shower/toilet chair. Figure 11.4 shows the first prototype in a fully extended position, and Figure 11.5 shows the fully retracted position. The mounting block is made of aluminum and held together by lo-32 screws. The arm is made of 1 square stainless steel tubing and rotates from the extended forward position to the rear stop on the clamp out of the way of an individuals feet. Square tubing is used to prevent lateral arm rotation that is a common problem with the currently used wheelchair foot supports. A sleeve with a cylindrical rod welded to the front fits over the rotating arm and may be adjusted for height variation using a locking pin. These pin and adjustment holes can be seen in Figure 11.4. The round rod provides for the mounting of a footplate. A standard footplate from a wheelchair is used for easy access of replaceable parts. The aluminum parts are treated with alodine, and the stainless steel parts are painted to prevent corrosion. In this way, these retractable foot supports make bathing and transportation to and from a wheelchair an easier task. Detailed drawings are available on request. Figure 11.5. Supports retracted.
172 NSF 1995 Engineering Senior Design Projects to Aid the Disabled Battery Powered Door Opening Device Designer: Pablo Samsing Supervising Professor: Robert J. Hirko, Ph.D. Aerospace Engineering, Mechanics, and Engineering Science University @Florida Gainesville, FL 3261 l-6250 INTRODUCTION A door-opening device is necessary for people lacking the strength to open doors. This is a problem for people who are ambulatory with walkers or canes, as well as for those in wheelchairs. The battery-powered door opening device, BPDOP, is activated by applying a downward pressure to the handle. Its drive is shown without its cover in Figure 11.6. Additionally the device can provide support for the user. It can also be designed for use by someone in a wheelchair. Figure 11.6. Drive Unit Without Cover. SUMMARY OF IMPACT The daily activities of people with disabilities, specifically lacking the strength to open doors, is complicated by the lack of doors with the ability to open automatically. The project that is designed is used for almost any application with the requirement that the operator be able to turn the handle to unlatch the door. Operators with the obstacles of pressurized doors or large doors will be able to overcome them and gain more accessibility. The primary goal of this device is to decrease the dependence on facilities to be equipped with automatic doors. TECHNICAL DESCRIPTION Requirements that are applied for the design of this door-opening device are as follows. First, weight of the device is kept in mind when designing and choosing materials. The BPDOP needed to be lightweight in order that it may also be used as a cane and carried around as such. The main body of the BPDOP is aluminum that is lightened by removing material that is structurally not necessary. The wheels are made of lightweight foam, with a plastic center. Two wheels, located at the front, transferred the force to move the device and another two wheels, located on the bumper, acted as push-rollers. The entire main body is covered with a toy lexan replica of a truck and attached to the unit by plastic screws with wing nuts, for ease of removal. The rest of the device, which consisted of the cane and handle, are made of aluminum and plastic, respectively. The BPDOP is intended to be used daily. In order to maintain the usability of the device, a rechargeable battery is used as the source of power. The advantages of using a battery are its ease of recharging and installation along with its small size. The motor and gear set up that powered the motor came from a modified Makita angle drill (Figure 11.7). The battery, located at the top of the cane, can be easily changed and replaced with a recharged battery. The application of the BPDOP required that it be easy to use with very little physical requirements. The unit is designed for a person with limited strength and dexterity. The only requirement, aside from being able to walk and carry the unit, is that the user be able to transfer his/her weight. The unit is activated by applying pressure to the handle. The handle is installed at a ninety degree angle from the cane (Figure 11.8) so that the unit will be activated by the user simply leaning into the cane. When the user leans into the cane, the trigger is pushed by a spring-loaded trailing wheel, located behind the unit. The handle can also be adjusted for users of different heights by
Chapter 11: University of Florida 173 just turning it counter-clockwise, moving the handle up or down on the cane and then tightening it by turning the handle clock-wise. The unit is designed to be affordable by using inexpensive materials. The cost of the materials of a single unit is about $270. Figure 11.7. Drive Unit and Similar Drill Motor. Figur-e 1 1.8. Entire Unit With Cover.