APPLICATION OF ERGONOMIC PRINCIPLES IN COMPUTER WORKSTATIONS TO ALLEVIATE HEALTH RISKS FROM EXTENDED COMPUTER USE __________________________ A Thesis Presented to the Faculty of the College of Science and Technology Morehead State University _________________________ In Partial Fulfillment of the Requirements for the Degree Master of Science _________________________ by John M. Awbrey April 27, 2015 UMI Number: 1587486 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 1587486 Published by ProQuest LLC (2015). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106 - 1346 Accepted by the faculty of the College of Science and Technology, Morehead State University, in partial fulfillment of the requirements for the Master of Science degree. ____________________________ Dr. Nilesh Joshi Director of Thesis Master’s Committee: ________________________________, Chair Dr. Ahmad Zargari _________________________________ Dr. Yuqiu You ________________________ Date APPLICATION OF ERGONOMIC PRINCIPLES IN COMPUTER WORKSTATIONS TO ALLEVIATE HEALTH RISKS FROM EXTENDED COMPUTER USE John M. Awbrey Morehead State University, 2015 Director of Thesis: __________________________________________________ Dr. Nilesh Joshi Ergonomic design of computer workstations has fallen behind recent research findings in the field of ergonomics. The health of employees and other people who work in front of a computer for extended periods of time can be improved through the use of applying these new ergonomic practices. Through a careful study of recent ergonomic research findings, the purpose of the research is to design a workstation which improves the health and productivity of long term computer users. Accepted by: ______________________________, Chair Dr. Ahmad Zargari ______________________________ Dr. Yuqiu You ACKNOWLEDGEMENTS Dr. Nilesh Joshi of Morehead State University for his readiness and expertise in mentoring the production of this thesis. Dr. Ahmad Zargari of Morehead State University for his consistent availability and dedication to all students. Dr. Yuqiu You of Morehead State University for her assistance in the formulation of testing and verifying the design. Tange Awbrey of Morehead State University for her constant encouragement and providing an outlet for new ideas. Buddy Awbrey, because dogs help to always remind us of how wonderful life can be when under stress. Table of Contents Chapter 1: Introduction ................................................................................................................... 1 1.1 Overview ............................................................................................................................... 1 1.2 Limitations ............................................................................................................................ 2 1.3 Definition of Terms ............................................................................................................... 4 1.3.1 Ergonomics ..................................................................................................................... 4 1.3.2 Average User .................................................................................................................. 5 1.3.3 Target Consumer ............................................................................................................ 5 1.3.4 Wheelchair User ............................................................................................................. 5 Chapter 2: Literature Review .......................................................................................................... 6 2.1 Average Users ....................................................................................................................... 6 2.1.1 Wendling – “Forget About Sitting Up Straight…” (2007)............................................. 6 2.1.2 Hedge – “Ergonomic Seating?” (2013) .......................................................................... 7 2.1.3 NASA Skylab – “NASA-STD-3000” (1995) ................................................................. 9 2.2 Wheelchair Users ................................................................................................................ 12 2.2.1 Ding – “Usage of Tilt-in-space, Recline, and Elevation... Wheelchair Users” (2008) 13 2.2.2 Leister – “Effectiveness and Use of Tilt-in-space and Recline Wheelchairs” (2005) .. 16 2.3 Historical Data Analysis ..................................................................................................... 16 Chapter 3: Ideation ........................................................................................................................ 20 3.1 Process of Design ................................................................................................................ 20 3.2 Keyboard and Mouse Configuration Considerations .......................................................... 20 3.2.1 Keyboard and Mouse Configuration A ........................................................................ 21 3.2.2 Keyboard and Mouse Configuration B ......................................................................... 22 3.2.3 Keyboard and Mouse Configuration C ......................................................................... 23 3.3 Chair Configuration Considerations.................................................................................... 24 3.3.1 Chair Configuration A .................................................................................................. 25 3.3.2 Chair Configuration B .................................................................................................. 26 3.3.3 Chair Configuration C .................................................................................................. 27 3.4 Monitor Position Configuration Considerations ................................................................. 28 3.4.1 Monitor Calculations Set 1 ........................................................................................... 30 3.4.2 Monitor Calculations Set 2 ........................................................................................... 31 3.4.3 Monitor Calculations Set 3 ........................................................................................... 33 3.5 Monitor Position Configuration Considerations ................................................................. 35 3.5.1 Monitor Position Configuration A ................................................................................ 35 3.5.2 Monitor Position Configuration B ................................................................................ 36 3.6 Configuration Combination................................................................................................. 37 Chapter 4: Final Design ................................................................................................................ 39 4.1 Overall Design..................................................................................................................... 39 4.2 Modelling of Configurations ............................................................................................... 40 4.2.1 Overcoming Design Complications .............................................................................. 41 4.3 Modelling around the human body ..................................................................................... 44 4.4 Parametrics and Connections .............................................................................................. 46 4.5 FEA and Materials .............................................................................................................. 48 4.6 Full Assembly Evaluation ................................................................................................... 50 Chapter 5: Discussion, Future Testing, and Closing..................................................................... 53 5.1 Advantages of the Design ................................................................................................... 53 5.2 Disadvantages of the Design ............................................................................................... 54 5.3 Future testing ....................................................................................................................... 54 5.4 Closing ................................................................................................................................ 55 References ..................................................................................................................................... 56 Appendix ....................................................................................................................................... 58 1-A: Keyboard and Mouse Configuration Design Hand Sketches ........................................... 58 1-B: Chair Configuration Design Hand Sketches ..................................................................... 62 1-C: Monitor Position Hand Calculations ................................................................................. 65 1-D: Monitor Position Configuration Design Hand Sketches ................................................... 68 2-A: Detailed Part Drawings ..................................................................................................... 70 2-B: Full Assembly Drawings and Renderings ......................................................................... 93 Chapter 1: Introduction 1.1 Overview Ergonomics at work has become a rising concern in the modern workplace. A number of studies have been made to maximize the safety and comfort of employees who work on computers for long periods at a time, detailed in the background research for this design. The results of the background research set by Awbrey (2014) will be used in the design of a workstation that seeks to place every element needed for computer work in the optimal position for safety and ease. The purpose of this thesis is to create a working concept for a workstation which incorporates the latest research into ergonomics which can be developed into a product for production and sale to the general market. Picture a person working at a computer all day. Generally what comes to mind is someone sitting, perhaps a little hunched over, typing away at a keyboard. They sit in front of a desk which has their monitor on it, perhaps even their keyboard and mouse which they are typing and clicking furiously at. This traditional desk and chair setup is actually contrary to the results of many modern ergonomic studies. The poor ergonomics of a modern workstation featuring upright posture, positioning of a computer screen on the flat desk with the keyboard and mouse, and many other small details can actually be taxing on the human body and can lead to injury according to the Canadian Centre for Occupational Health and Safety (2009). By redesigning the modern workstation with the latest ergonomic research in mind, the health, comfort, and productivity of employees can be increased and preserved. Certain limitations on the design will help to ensure that the workstation will last for a long time and be cost effective to the customer. The idea of the fully ergonomic workstation is not new as there are other models on the market. Most of these workstations however cost well over one thousand dollars or even more according to a basic search for them on Amazon (2014). This makes safety and health unobtainable for many companies and people in their home offices, where they can spend as little as one-hundred fifty dollars on both a desk and chair. There are a great deal of considerations that must be taken into account through this design, and therefore the focus is entirely on low cost production and effective use of ergonomic research. 1.2 Limitations It is the decision of the designer to limit the parts used in the design heavily. The first and perhaps the hardest limitation to overcome is not using springs. The second limitation is to avoid using tension as a method of holding something up against gravity. The third limitation is to refrain from including any hydraulics. These limitations offer a number of challenges to overcome, but by adhering to them, the design will gain a few significant advantages with relation to the key goals of the design. Springs are extremely helpful when designing parts which can be adjusted by the consumer. Most modern chairs and adjustable desks have a number of them for different purposes. While springs themselves hold little danger when used correctly in a design, they do wear out over time. When the springs eventually wear out, they fail, and could potentially cause injury unless further fail-safes and expense is spent on the assembly. The main reason for preventing the use of springs in this design is that their use generally requires the design and fabrication of special 2