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DOOR-OPENING DEVICE FOR WHEELCHAIR USERS

M. Virginia Marsh1, Kenneth W. Fields2, Shaun D. Glasgow2, and Beth A. Todd1 1Department of Engineering Science and Mechanics / 2Department of Mechanical Engineering University of Alabama, Tuscaloosa, AL 35487

ABSTRACT

Disabled individuals often have difficulties opening doors for themselves, and commercial door opening devices are very expensive for the typical homeowner. In this project, an affordable door-opening device was created. This is an electro-mechanical system operated on the exterior of the building by a keypad and on the inside of the building by a button. Construction, testing and evaluation of the model was completed in compliance with the codes and regulations applicable to public facilities.

BACKGROUND

Title III of the 1990 Americans with Disabilities Act (ADA) requires businesses to have doorways and doors which are easily accessible to those with physical disabilities. In addition to providing ways around the stairways that approach many entrances, doors themselves must be designed such that they can be easily opened. Many businesses have solved this problem with commercially available systems which cost $1000-$1500 (1). However, disabled individuals also require access to their homes, and the cost of a commercial door-opening system is prohibitively expensive for many individuals.

STATEMENT OF THE PROBLEM

The purpose of this project was to design a device costing $300 or less which can open a typical residential door. The device should comply with the codes and regulations for public buildings.

RATIONALE

To understand the issues of this project, research was done on applicable codes and regulations as well as existing devices. To be a useful device, the door must remain fully functional for the nondisabled population. Therefore, only minimal modifications can be made to the door itself. The primary source of information on accessibility for the disabled was the ADA (2). Regarding access to doorways, ADA requires:

  • 32 in. minimum clear width opening
  • 3-5 lb maximum door opening force
  • 3 second minimum opening time
  • 15 lb maximum force to stop door movement
  • 90 minimum opening angle
  • easy-to-use door hardware (doors with lever handles, etc.)

The Life Safety Code (3) was consulted to determine the following safety requirements:

  • In the event of power failure, door may be opened manually for safe means of egress. (Section 5-2.1.9.1)
  • If a power-operated door is used as an exit, it must swing by manual means. (Section 5-2.1.9.2)

DESIGN

Development of Design Criteria In addition to ADA regulations, a group of wheelchair users were contacted to discuss problems that they had with residential and commercially available doors. Their comments included: /

  • turning door knob, pushing or pulling on door requires significant upper-body strength
  • assistance required from another individual
  • operating door independently leads to wear and tear on door, doorjamb, and wheelchair
  • inability to efficiently open door restricts means of entrance and egress
  • purchasing a commercial door-opening device requires a significant financial investment

The door-opening device was designed to address these issues. The design consists of an electrically controlled system that is operated manually by the wheelchair user with a keypad on the outside wall and a push-button on the inside wall. This system, shown in Figure 1,

  • eliminates unintentional activation of the opening device
  • removes the opening and closing load from the disabled individual
  • eliminates the need for assistance
  • requires little upper-body strength
  • allows the user freedom to move without obstruction from the door and doorjamb, thus preventing damage to the wheelchair

Linkage Mechanism

The linkage connecting the door and the frame consists of a telescoping mechanism. As shown in Figure 2, a simple linear bearing allows the arm to extend and retract with smooth operation. The components of the mechanism include a ball plunger/detent configuration (break-away mechanism), sliding shaft stock, and an AB down rod (essentially the same as galvanized pipe) with a PVC sleeve insert. Electrical Components The electrical components are placed in a box, shown in Figure 3, which is placed above the door frame so that it does not interfere with the mechanical operation of the door. The electrical components include: control relays, motor, capacitor, limit switches, transformer, and an electric door strike. The motor was sized according to the ADA regulations regarding opening time and force. To minimize the cost of the door-opening device, parts and materials were purchased at a local hardware store and wholesale distributors. The device was designed to minimize machining time and effort.

DEVELOPMENT

A construction, assembly, and installation guide was written to discuss the procedures used and necessary parts, materials, and tools for the door-opening device. The device was demonstrated as a Senior Mechanical Engineering Design Clinic Project. It was evaluated based on repeatability, ease of operation, ease of manufacture, and required number of modifications to the door and the door environment.

EVALUATION

After assembly the door-opening device was installed on a standard residential door composed of steel casing with a foam-core insert. To provide stability, a wall section was constructed and used for support. This prototype device works reliably and allows easy access for a disabled individual to his/her home. All of the codes and regulations for entrances to public buildings were met. Most importantly with respect to safety, the door can be operated manually during a power failure. The door-opening device described in this paper costs about $300 to build. Machining was minimal, requiring only a small amount of welding and other basic machine-shop operations. The only modifications were to the structure around the door as opposed to the door itself. The box containing the electronics was installed above the door frame. The keypad allowing entrance would be installed on the outer wall of the building, and the button allowing egress would be installed on an inner wall. All of the electrical wiring would go through the wall to the door-opening device.

DISCUSSION

The resulting semi-automatic door-opening device met all of the design criteria. However, several modifications could be made to improve the device. The ball plunger/detent configuration did not work as expected, although the door can still be used in the event of power failure. One possibility for improving the design would be the use of a clutch to engage and disengage the motor and allow for a break-away device. A timed-delay could be implemented into the circuit. This would allow for escape for someone who is trapped in the path of the door. The device would operate if the proximity piece did not strike one of the limit switches within a pre-set time. Additionally, a stronger motor with more running torque would reduce maintenance and extend the motor life. There is a significant need for a door-opening device for disabled homeowners. With the modifications described above, this device could be a realistic solution.

Figure 1. Door-Opening Device Assembly

Figure 2. Linkage Mechanism

Figure 3. Electrical Components

REFERENCES

1. Mr. Robert L. Todd, M.S., C.R.C., Information Specialist, Georgia Institute of Technology, Atlanta, Georgia.

2. Americans with Disabilities Act [ANSI-A117.1-1986, Section 4.13]

3. Life Safety Code [101-12, Sections 5-2.1.9.1 and 5-2.1.9.2]

ACKNOWLEDGMENTS

We wish to express sincere appreciation to the Mechanical Engineering Department, the Design Clinic, and the following individuals at The University of Alabama, Tuscaloosa, Alabama: Dr. Steve Kavanaugh, Associate Professor, Department of Mechanical Engineering [faculty advisor]

  • Dr. Joey Parker, Associate Professor, Department of Mechanical Engineering, [faculty advisor]
  • The mechanicians of Engineering Technical Services
  • Mr. James Sanders, Departmental Technician, Department of Mechanical Engineering [machining of parts]

M. Virginia Marsh The University of Alabama Dept. of Engineering Science and Mechanics Box 870278 Tuscaloosa, AL 35487-0278 (205) 348-4663 Fax: (205) 348-7240

Ball Plunger/Detent Configuration Sliding Shaft AB Down Rod with PVC Sleeve Gear Motor Capacitor Power Cord Limit Switches Control Relays Transformer for the Strike Strike Wires Box Mounted on Top of Door Case Molding Linkage Door Case Molding Door