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reconditioning seating in a static society

master of interior architecture & product design kansas state university | apdesign | 2011 whitney thomure furniture design



reconditioning seatiexplorations ng in a stati c society in dynamism

master of interior architecture & product designkansas state university iapd 815 advanced studio programminglorraine cutler whitney thomurefall 2010 furniture designbrown


project abstract The premise of the investigation was to challenge traditional seating scenarios. In this day and age it is extremely important to choose a task chair that encourages healthy sitting postures and combats the growing effects of seated careers. In order to create a more dynamic chair, it was integral to investigate different impact and stress dampening products. Although these products dampen the forces exerted on the body, it became apparent the product needed to cooperate with mechanical components that stimulate movement of the seat. A product that married both ideas was the skateboard. The wheel mount of a skateboard is called a truck and has a ball-and-socket joint that allows for rotation to occur around an irregular manipulable axis. Challenging the established office chair component-based construction


was difficult at first, but once the column was reassessed, the need for a five-star base became obsolete. Lowering the center of gravity with a non-traditional base allowed for the creation of a four-footed foundation and interacting legs. Overall, by questioning the need for standard office chair components, dynamism in design and function can be achieved and could possibly change the way users interact with chairs in the future.



part one table of contents proposal 7 background information 15 evaluation methods 23 field of study 29 case studies 37 conclusions 45 part two 49



proposal To come to a distinct thesis design problem, I evaluated the need for people to have seating that would benefit, rather than harm, them. My method consisted of narrowing

problem objective hypothesis

down initial thoughts and theories to the distinct problem, identifying goals, and hypothesizing a design problem to prove this project will, in fact, accomplish what it was set up to achieve.


part one

problem evaluation Overall I realized there is a need to create a chair that satisfies the level of comfort and body movement required for professionals who work at a desk in an office setting. Over the four years I my time to studio and, consequently sitting, I have discovered how uncomfortable chairs can become. When I realized that, “over 75% of work in industrialized countries is done while sitting,� (1) I contemplated over how much time and adult actually spends seated. every working professional spends hours seated in the office, in transit to or from work, relaxing at home, and in transitional times during the day. I decided that at least one of those scenarios should be modified to make an impact on lessening the physical strains caused by poor sitting habits and chair composition. From the many remedies I devised to help ease pain


RĂŤrgonomics reconditioning seating in a sedentary society

around Seaton Hall to


in my back, to the walks

problem evaluation


allow my legs to wakemore



situations that would keep as I worked. This query resulted




problem: To create a chair with a seat that engages



my body more engaged


up, I began to theorize

chapter title

the user, while it eliminates bad posture and low abdominal core strength associated with sitting at a desk for long spans of time.


part one

objective I propose to create an office-seating scenario that decreases the physical effects associated with sitting in one position for the standard eight-hour working day that could be implemented on existing office chairs. productivity in the office environment is key. The more “work” an employee can handle determines how much of an asset they are to a company. Stress is placed on the employee to produce a certain amount of work output in a certain amount of time when their bodies are not being engaged as they often should. Proper work equipment should be available to every office as a tool to increase productivity, not to impair the employee’s physical health. Formulation principle




design include

aspects from the fields of kinetic physiology, workplace functionality,



introduction of biomechanics in jobs or settings where people


Rërgonomics reconditioning seating in a sedentary society



are expected to sit for long periods of time. I propose to involve additional fields that may also shed insight onto human functionality and growth. this would include studies of child development and physical ability,





chapter title


exercise practices. By evaluating information that has been collected by researchers and practical information of existing products and customer evaluations, I will discover product successes and shortcomings. With that, I concluded that any and all improvements on workplace seating design would aim to reach and fulfill the following goals. The design should provide a supportive, comfortable, comfortable, and dynamic chair seat for working professionals. The seat should adjust to suit whomever may sit in the chair.


part one

The design should help to prevent problems that result from sitting in unresponsive office furniture. The design will adjust to accommodate those who don’t fall between the fifth and ninety-fifth percentile range of women’s and men’s considered body sizes.


Rërgonomics reconditioning seating in a sedentary society


hypothesis From the problem evaluation and objective, I formulated a hypothesis to test the following statement: If





designed to react and interact with the user, then the potential pain and physical effects of sitting sedentarily at a desk for hours would be diminished and as a result, there would be an increase in the work output of the user. Throughout the design discovery phases, the hypothesis will serve as a point of reference and focus, so as not to lose sight of the goals fueling the project.




a m u h

Office Chair




background information To better understand the background of office seating, I assessed three aspects of evolution. all three areas, human, office medium, and office chair design, hall evolved on a major scale in the last 50 years. Changes of work scenarios have affected human posture, office

evolution of office medium evolution and postural adaptation evolution and office seating

information has changed from manual filing systems to computerized systems, and office seating has adapted to suit the worker according to task.


part one

evolution of office medium Technology has changed how the world functions, in the last 50 years there has been a noticeable centralized attitude towards organization and productivity efficiency. Through the use of technology, both of these aspects are met. The introduction of the computer in the workplace has changed industry in many ways. For example, productivity levels have all but plateaued since the computer became the most important tool in the workplace. Organization of files, programs and communication have eliminated the usual work breaks of getting up, out of your chair and walking to find something or to talk to someone in person. Decentralized methods of work allowed for more movement and flex in daily routines, which are now lacking. In an article by Waldemar Karwowski Steven



William workplace

arrangement and composition


RĂŤrgonomics reconditioning seating in a sedentary society

is evaluated. Karwowski and Marras support that considerations should be made to compensate for the lack of movement in common Specifically

arrangements. the


evolution of office medium

background information

Occupational ergonomics: design and management of work systems states, “… with the advent of the



automation, and the associated rise of multoskeletal complaints among office workers, a greater degree of attention began to be focused on the fundamental requirements of seating (Dainhoff & Dainhoff, 1986). In particular, the cubist assumption was challenged. Granjean et al. (1983) called the upright posture “wishful thinking” and indicated that the natural working posture would be one in which an adjustable backrest allowed the trunk to be inclined rearward.”


part one

evolution and postrual adaptation For thousands of years, the




body to


surroundings to better suit its needs and ability to complete tasks. The working roles of people, since




dramatically skeletal



so the of

bodies are adapting at a higher rate than ever before. With the shift from a more agrarian lifestyle to the office-based workforce, it is true that, “Substantial health costs and the increase in sedentary occupations have led to a considerable amount of attention directed toward office seating, as the chair industry represents 25% of a $10 billion-a year office furniture industry in the United States.�


RĂŤrgonomics reconditioning seating in a sedentary society

background information

evolution and office seating Office spatial trends have often influenced seating design. Only more recently, with the abundance of seated jobs and decreased mobility at desks with the introduction of the computer, the office chair has emerged as an integral tool for productivity. In evaluating the first specialized office chair from 1849, the Centripetal, evidence of an adapted leg structure is seen on a typical nineteenth-century seat. The Centripetal had increased movement capabilities and acted as a more dynamic seating element suited to working at a desk. In the 1970’s, ergonomic studies and theories became popular. While exploring the body as a n influence of form, manufacturer’s began to expand the office furniture industry by considering consumer comfort and health. As form became more


part one

complex to increase dynamism, materials and features became even more important. Today Herman Miller released the SAYL, a chair that uses a penetrable material for the backrest support. Instead of tensioned mesh, customary in modern office furniture, a rubber composite serves as support, while it comforts the back. The diagram to the right showcases the most influential steps in design and ergonomic consideration.


RĂŤrgonomics reconditioning seating in a sedentary society

evolution and office seating

background information

Brief history of office seating




evaluation methods The following research methods were instrumental in evaluating industry trends and existing design concepts.

Pe単a method literature search


part one

Peña Method The



presented connections to




n bala

ar b m lu


om gr on


concepts and keywords that




research investigation

extremely conducting for of

the the

design problem. After completion of the Peña template,


considerations for investigation became apparent. These concerns included: price reasonability, interchangeable parts, and adaptability. Additionally, utilizing this method, it was easy to identify specific parts of chairs that would become the main focus of the research, design and prototyping efforts of this project. The seat pan became a focal element in the investigation. Evaluating how the user’s body interacts and reacts to suit the chair and to what extent the lumbar support becomes a burden and less of a complementary element.


Rërgonomics reconditioning seating in a sedentary society

evaluation methods

literature search After analyzing the Pe単a Method results, some key elements became the basis of the research analysis. The main ideas in question: The idea that the body is constantly trying to balance The needs and utility of lumbar support to ergonomic design Locations of pressure impact Effects of staying sedentary in a seated position The idea that the body is forced into a static state while sitting at a desk Resources


re ressu


ry enta




these elements spurred a realization of how each were inextricably linked to one another, especially in reference to effective chair design.



field of study Connections between different fields of study became important to fully evaluate the design problem. Using information gathered in these fields allowed connections to similar

child development ergonomics biomechanics

scenarios enhanced and created new concepts that I aimed to test for validity.


part one

child development In order to understand the growth and fundamental steps



experiences to achieve balance,



child development as a field of study. It is a very excellent way to evaluate the importance of products and objects and the way they interact and aid in achieving ‘perfect’ balance. Shown here is an image of the Australian Bambino Bumbo Baby seat. The seat aids with the child’s transition from holding their head up on their own, to sitting upright on their own. The soft molded rubber supports the child’s legs between and around the waist. The product has miscellaneous uses and is especially helpful for parents of young children and those with disabilities.


Rërgonomics reconditioning seating in a sedentary society

field of study

ergonomics Ergonomics have played an important role in office chair design since its major implementation in the 1970’s. The Baumbach Saddle Seat was a true testament to the advocacy of “correct seated posture”. From An investigation into the immediate effects on comfort, productivity and posture of the BaumbachTM Saddle Seat and a standard office chair, the results of the study exposed the differences between the saddle seat and a regular office chair. It showed that although the chair did achieve high trunk-to-thigh heights, “general discomfort increased






seat being used and is



with levels

increasing as the time spent performing work tasks increase.” With



as these it becomes


part one

apparent that there are definitely some discrepancies in ergonomic chair use and design. The article explains that lack of education of ergonomics leads to poor posture, productivity and comfort levels in even the most ergonomically appropriate chair. Today, a new trend in the office environment utilizes stability balls as a seating alternative. In the article, Stability Ball Versus Office Chair Comparison of Muscle Activation and Lumbar Spine Posture During Prolonged Sitting, the authors explore the ball compared to normal office seating and found that, “There does not appear to be any advantage to using a stability ball as an office chair. No postural or muscular activation



observed between the ball and the chair, with the exception of reduced pelvic tilt while sitting on the ball.� By evaluating existing chair designs


RĂŤrgonomics reconditioning seating in a sedentary society



theories, I hope to gain a


field of study

better understanding of what impacts the way the body interacts with planes, postures



associated with them.


part one

biomechanics Throughout the fall semester, I have explored the world of biomechanics. When considered, biomechanics can explain some of the discrepancies in comfort and effectiveness of ergonomic design. As defined by Ground Up Strength, biomechanics is, “… the physics of human motion. A study of the forces produced by and acting on the body. The functional and anatomical analysis of biological systems from a mechanical perspective.” While ergonomics focuses on the support and corrective interaction that elements of a chair have on the human body, biomechanics attempts to understand the physics and measure



exerted on the body in a variety of situations. According




Effects of backrest design on




and seated

work, “…large changes in


Rërgonomics reconditioning seating in a sedentary society

posture are indicative of discomfort




field of study

“micro� movements are necessary to alleviate pain cause by static lumbar and



postures. tracking

CP (center of pressure) motion may prove to be an effective predictor of discomfort and backrest preference.�



said, it is imperative that elements that provide marginal shifts in movement be included in the final design.



case studies Through investigation of existing products, I was able to gain understanding of the type of elements and materials utilized and the industry feedback of typical ergonomic

Steelcase Knoll Vitra



part one

Steelcase With the LEAP Productivity and Health Impact Study, published of Steelcase’s website, the company was able to explore and document the changes and in

improvements productivity


among users with proper ergonomic


Over a year-long period, Leap owner productivity and comfort levels were recorded in conjunction with recordings from ergonomically trained and untrained non-Leap users. The result of the study showed an increase in productivity of 17.8% among the Leap users with ergonomic training compared to the control group and trained group. (7) With this information, it is easy to infer that ergonomic training is essential in the effective use of the chair.


RĂŤrgonomics reconditioning seating in a sedentary society

case studies

Knoll Ergonomic guidelines were specifically outlined in reference to the Generation chair by Knoll in Generation by Knoll Independent Ergonomic Evaluation by Dr. Tim Springer of HERO, Inc. In the article he claims, “Innovation that enables a product to exceed or transcend the criteria must be considered valuable.” (8) The criteria that Springer outlined includes: - support the user’s body - support the full range of activity the user performs on a daily basis - promote movement - incorporate cognitive ergonomics - support performance - be easy to use - do no harm This list is the basic standard for which all chairs should be based upon, not limited to.


part one

Vitra Intrigued by the seat material, the Vitra 03 became a case study for possible seat mediums. The seat is made of highdensity polystyrene foam around a frame of steel. This slender construction gives the appearance of a light-airy chair, but in fact it is very sturdy. The seat flexes a little when seated but is still supports the body. I am very interested in how similar materials would cut down on bulkiness but add to comfort and support of the spine. Vitra is a company that achieves high design and comfort. People are intrigued by chairs that are more simplistic and don’t look like ‘work’ chairs. I intend to draw material and form inspiration from the 03.


Rërgonomics reconditioning seating in a sedentary society

case studies



conclusions I gathered information to support the theories and concepts that the proposal research supported.

resource information looking forward


part one

resource information One article that I found while nearing the end of my research phase incorporated most, if not all, of the concepts I investigated. Movement Variability and the Use of Nonlinear Tools: Principles to Guide Physical Therapist Practice, showcase a new trend in the Kinesiology field. In order to receive the maximum results from an experiment or training session, variables must be utilized. This is pertinent to the project proposal became without variables; a chair is essentially a raise hard surface to balance on. When the variable for comfort is considered, padding is inserted or lumbar support is added. Conclusions from articles were, for the most part, inconclusive because they lack the ability of controlling other variables. The use of “Nonlinear” method of testing



evaluating, all


and the overall results they caused. Thus, “there is


Rërgonomics reconditioning seating in a sedentary society

mounting evidence of the importance of variability in normal movement, which reveals variation not as error but as a necessary condition


resource information



Variability reflects multiple options providing


movement, for


adaptive strategies that are not reliant on rigid programs for each task or for each changing condition encountered. Optimal variability as a central feature.�(9)


part one

looking forward In the coming semester I plan to take the information gathered and cultivate design ideas, prototypical models, conduct questionnaires and surveys, and continue to evaluate the ways to alleviate stress and pressure on the chair user. Included are a few sketches of ideas for impact dampeners that could fit onto an existing structure. I plan to model test fittings to evaluate the effects they have on creating mobility in seats.


RĂŤrgonomics reconditioning seating in a sedentary society

looking forward




chair history diagram inspired by British Airways business life article “A short history of the office Chair: A timeline” centripetal chair: Synthesis: Ergon: Supporto: FS Chair: Equa: Capisco: Aeron: Freedom Chair: Embody: YE8_gadgets 369 CHAIR:°-family-by-konstantingrcic-for-magis/ SAYL: new_chair_for_herman_ miller__17597.asp All other images courtesy of Corbis free-stock photography


Text Support

Carcone, S. M., & Keir, P. J. (2007). Effects of backrest design on biomechanics and comfort during seated work. Applied Ergonomics, 38(6), 755-764. Chen, L. C., Metcalfe, J. S., Jeka, J. J., & Clark, J. E. (2007). Two steps forward and one back: Learning to walk affects infants’ sitting posture. Infant Behavior & Development, 30(1), 16-25. Gadge, K., & Innes, E. (2007). An investigation into the immediate effects on comfort, productivity and posture of the bambach saddle seat and a standard office chair. Work (Reading, Mass.), 29(3), 189-203. Gregory, J. P. E. (2006). Stability ball versus office chair: Comparison of muscle activation and lumbar spine posture during prolonged sitting. Human Factors, 48(1), 142-153. Harbourne, R. T. (2009). Movement variability and the use of nonlinear tools : Principles to guide physical therapist practice. Physical Therapy, 89(3), 267-282. Pynt, J., Mackey, M. G., & Higgs, J. (2008). Kyphosed seated postures: Extending concepts of postural health beyond the office. Journal of Occupational Rehabilitation, 18(1), 35-45. Rice, T. (2009). Generation by knoll independent ergonomic evaluationKnoll, Inc. Evolution of Seating Spaces magazine/17-04/pl_design



RĂŤrgonomics reconditioning seating in a sedentary society

part two

f o n o i t a t n y e r m o e le h p t n im 1 g i 1 s 0 2 de g n i r p s




reconditioning seatiexplorations ng in a stati c society in dynamism

master of interior architecture & product designkansas state university iapd 815 advanced studio programminglorraine cutler whitney thomurefall 2010 furniture designbrown



part two table of contents part one feedback 55 design stages 63 design implementation 83 construction 97 conclusions 109



part one feedback With a rocky end to the semester, my presentation left me feeling that I needed to re-evaluate the research findings and re-identify what tangible product the problem would actually be

what exactly are you designing? focus on what you want to change



part two

what exactly are you designing? After




question, I was sent back to the drawing board. Initially the project proposal



creating an entire chair, but after initial research, I began thinking of specific changes to implement on existing products. For example, use of impact dampening technology through available products, I could challenge the rigidity that is present in most chairs and add variables of change and comfort that would result in a more dynamic chair. Replacement of other parts could also lead to more active seating elements, such as backrests or castors. I purposely did not define the exact product I intended to design, as I wished to use the research findings to assess the most appropriate solution.


RĂŤrgonomics reconditioning seating in a sedentary society

part one feedback

focus on what you want to change I had set out to create an interactive seat that allowed the user to operate and move in a way that complemented the varying degree of office work they performed. This included a wide scope of users and tasks that needed to be addressed equally. Normally when you sit in an office chair you are more-or-less anchored in one location with the ability to move the entire chair with the aid of castors. Limited fluctuation of seating position is available by a 10-degree tilt that most chairs offer, but the majority of the tilt is afforded in the backwards-lean direction. That aspect only promotes relaxation of the abdomen and puts stress on the lower legs. If the user wants to lean forward for a bit to rest or resituate their legs, it is achieved by a whole body maneuver, which often included lifting the entire body off the seat. I ask: Why do you have to get out of a seat to get comfortable? For inspiration of a dynamic chair, I looked to the exercise ball. In part one [p. 31 field of


part two

study of ergonomics] I researched the implications of using an exercise tool as a permanent replacement for a chair and found the ball with no significant pors or cons to dissuade the user from continuing or discontinuing use. I discovered, after using an exercise ball for a month’s time, I have more movement around the axis, but have awkward approaching and dismounting interactions. Not to mention that, at times, the ball does not move like an office chair, which impedes my ability to lean and perform work. Overall, I do not think an exercise ball can be sufficiently used as an effective office seat substitute. Back




Identifying the pros and cons lead to the formation of essential elements to be considered in the final design.


RĂŤrgonomics reconditioning seating in a sedentary society

focus on what you want to change

part one feedback



design stages A major step in defining the new direction occurred in the design stages of the project. Following is a detailed account of the steps taken in the pursuit of creating a dynamic chair.

research - refocus target definition/clarification chair design exploration precedent study profile study axis change rotated legs mechanics study/profile definition


part two

research/refocus 21 January 2011 In the first meeting of the semester, I was in a astate of limbo and had yet to define my project. To begin, I evaluated my previously stated directive and hypothesis. Because there were no specific seating element defined in either of the statements, I considered the different seating types that are used in the office setting: stools and chairs. At that point, I was still considering the replacement of key parts of the chair that would alleviate the stress and add more dynamism. This would include salvaging antiquated models and implementing new hardware in crucial stress points. In addition to chairs, I evaluated the stool, which allows




standing height workstation. Conversely the downfall of stool design is the improper placement or guidance of feet. The effects include stiffness


RĂŤrgonomics reconditioning seating in a sedentary society



of the legs when the circulation of blood is cut-off to the lower extremities.


design stages


part two


24 January 2011

Once I defined the type of chair to focus on, I began to think of the reasons people buy new office furniture. From New Life statistically, “… each year, U.S. companies buy about 3 million desks, 16.5 million chairs, 4.5 million tables, and 11 million file cabinets. Experts estimate that about half this amount it thrown away annually: according to one estimate, that’s enough to furnish all the offices in Boston.” After further investigation, I noticed the majority of salvaged office chairs were manufactured in the early noneties when ergonomic office seating standards had been in place for about a decade. The volume of chairs produced could lead to the inefficiencies seen in the design and, especially in today’s age, the chairs were simply stylishly out-dated. Mechanical


parts for even the most current chairs are castors


Rërgonomics reconditioning seating in a sedentary society


design stages

and pneumatic columns. Using exploded views of the components I strove to understand what caused the failure of the parts. I discover the main similarity between their






construction. I concluded me




with all



chairs need a center column and five castors?�


part two

definition/clarification 26 January 2011 In this stage, clarifying the basic requirements of office seating played an integral part in my reevaluation of the essential components in the chairs. Rather that embracing the “toss-it� attitude, I began to measure the importance of the parts by OSHA standards and their role in the design of chairs. These standards state: Potential Hazards - chair with four or fewer legs may provide inadequate support and are prone to tipping - Inappropriate choice of castors, or a chair without castors, can make positioning the chair in relation to the desk difficult -

this increases reaching





computer components, which can lead to muscle strain, and fatigue.


RĂŤrgonomics reconditioning seating in a sedentary society

Potential Solutions - chairs chould have a strong, five-legged base - ensure that chairs have castors that are appropriate for the type of flooring at the


design stages

workstation While



outline the need for base and castor consideration, the North Carolina State University


Health & Safety Department provides a checklist to evaluate chairs. Some questions included: ERGONOMIC CHAIR CHECKLIST 1.

Chair has wheels or castors suitable for the floor surface. Yes|No


Chair swivels. Yes|No


Backrest us adjustable for both height and angle. Yes|No


Backrest supports the inward curve of the lower back. Yes|No


part two


Chair height is appropriate for

the individual and the work surface height. Yes|No 6.

Chair is adjusted so there is no

pressure on the backs of the legs, and feet are flat on the floor or on a footrest. Yes|No 7.

Chair is adjustable from the

sitting position. Yes|No 8.

Chair upholstery is a breathable

fabric. Yes|No 9.

Footrests are used if feet do

not rest flat on the floor. Yes|No The checklist, does not address possibilities of free movement tied to the use of castors on a five-legged base. I began to experiment



of base feet and non-traditional column placement. What if there was no column?


RĂŤrgonomics reconditioning seating in a sedentary society




examples, I noticed that legguiding ergonomic forms also achieved successful, movement situations.

encouraging Perhaps



design stages

design would include such considerations. I identified multiple source and uses for impact dampening products that reduce the stress exerted on the body by the absorption and spread of forces acting upon it. Resilient materials that found their original shape after sustaining a compressed



used in all of the cases. My design would include these devices.


part two


RĂŤrgonomics reconditioning seating in a sedentary society


design stages


part two

chair design exploration28 January 2011 I began to focus on how a chair could aid the body. promoting healthy back positions and foot placement has been addressed in many chair designs before. I evaluated how these examples worked and if they alleviated stress or caused different stresses. For example, the Balans Chair by Peter Opsvik was widely reviewed as a great innovation in supporting the body in promotion of good posture. Although posture, pressure, and dynamism are achieved, there is one large drawback: maneuverability. It is very difficult to get out of the chair after sitting in it for anytime at all. This disorientation could lead to lower productivity levels. Studying



revealed that users lacked opportunity



while using the chair. This leads to an increased static sitting position potential, which would not suit the proposed problem or theories.


RĂŤrgonomics reconditioning seating in a sedentary society

chair design exploration

design stages


part two

precedent study

02 February 2011

Research exploring alternative office chair solutions resulted in examples that mixed new concepts with existing chair construction elements. The fluidity in the examples is achieved by the use of bent plywood that starkly contrasts with the sleek metal structure. I will consider these examples in the strategic, as well as aesthetic, design of the piece. I purposely did not define the exact product I intended to design, as I wished to use the research findings to assess the most appropriate solution.


RĂŤrgonomics reconditioning seating in a sedentary society

design stages

profile study

04 February 2011

To start designing, I needed to understand what the essential points of impact are. I identified multiple area where the body needed support according to ergonomic resources and the study of other chairs. Having points, both in front and behind, is essential for balancing the chair. The seat pan and lumbar support were the primary examples of support that were present.


part two

axis change

07 February 2011

With these points established, I began to experiment with different profile curves that would lend support to the body and add dynamism to the overall design. Ultimately my goal was to create a chair without the normal center column and five-star base. This decision granted more freedom to manipulate the profile curve and leg/base connection.


RĂŤrgonomics reconditioning seating in a sedentary society

design stages

rotated legs

09 February 2011

Transforming the two-dimensional curves into the third dimension, the conceptual sketching lead to experimentation of the interaction aesthetic of the curves as formed legs. Observing the director’s chair connection and collapsing structure lead to the rotational possibilities of having two, interacting legs.


part two

mechanics definition

11 February 2011

Once I had made the decision to create interacting legs without the center pneumatic column, the need for maneuverability of height became the next focus point of the project. A system of interlocking grooves would give the user a chance to move and settle on that correct height for their stature. A simple, yet elegant, connection was necessary.


RĂŤrgonomics reconditioning seating in a sedentary society

mechanics definition

design stages



design implementation Exploring the methods of dynamism began with the construction of mock models and material studies. When outcomes proved to be favorable the elements were then assessed into the

first model mock-up study base changes final design

final construction.


part two

first model

17 February 2011

To achieve dynamism in both aesthetic and seat interaction, a system of components are necessary. The seat must move freely from the support structure so I was careful to devise the connection between those elements. From the Mock-up study, I observed the seat pan and lumbar support needed to rotate together so it moved easily around the wheel yoke of the skateboard trucks. A carriage that housed the seat truck was implemented underneath the seat and spanned to both arms, securing them and also serving as the height maneuverability. This allowed the chair to sit at the best height for the user and the armrests to adjust with the seat construction. The legs were derived from my original sketched of interlocking necks, but with a twist to include the height changes. Connecting the top of the legs back onto themselves added more stability and strength to the leg arrangement.


RĂŤrgonomics reconditioning seating in a sedentary society

The base consists of four feet that span about 2

first model

design implementation

feet apart on each side. The wide, low base adds stability to an axially dynamic composition. By ridding the construction of a fifth wheel, a more symmetrical chair is produced.


22.31 26.56



17.00 24.00

part two

2.00 1.00



RĂŤrgonomics reconditioning seating in a sedentary society

23.48 25.50

first model

design implementation

22.35 R1.00

24.00 24.14









part two

mock-up study 18 Feb - 16 March 2011 In the construction phase, I began to test my theories of dynamic seat hardware. I purchased a used skateboard and harvested the two trucks from the deck. I mounted on truck underneath the seat about two-thirds the overall size of the seat pan located from the front side where it would rest underneath the user’s core body weight and ischial bones of the pelvis. After testing the first prototype, it was apparent that more comfort would be afforded with the addition of a skateboard truck between the seat and lumbar support. The rotation of the seat would revolve the lumbar support, which added more motion through the truck. The lumbar support shape became troublesome where the shoulder blades hit. So revisions to the shape were necessary.




chair was very comfortable as you rotated around the skateboard truck. The feeling was similar to the movement


RĂŤrgonomics reconditioning seating in a sedentary society

experienced on an exercise ball, but with more stability for the times you want to feel

mock-up study

design implementation



part two


RĂŤrgonomics reconditioning seating in a sedentary society

mock-up study

design implementation


part two

base changes

17 March 2011

After my mid-critique, I evaluated ways to simplify the construction of the chair. I felt it was essential to be able to construct the chair in the facilities on campus as much as possible. The materials needed to achieve the flexed legs would prove too difficult to produce, even in a mock-up form, thermoforming Corian in the time constraints I faced. As I reevaluated the leg interaction, I felt it was extremely important to keep the legs crossing underneath the seat. I began to experiment with different configurations for legs and the addition of a separate base. Adding a base allowed the construction for the legs to consist



which I could produce in the Interior Architecture Furniture Workshop.


RĂŤrgonomics reconditioning seating in a sedentary society

base changes

design implementation


part two

final design

25 March 2011

Overall the aesthetic of the first iteration is upheld throughout the overall changes to the design. The major changes occurred with the implementation for a separate aluminum cast base and shape of the seat and lumbar supports. I was not very familiar with welding processes and evaluated my chair frame in relationship to how the welding process would be able to be supported. The implementation of the skateboard truck was the most important facet in this area of construction. The aesthetic value of the frame was not of the most concern. My goal is to revise this aspect in future iterations.


RĂŤrgonomics reconditioning seating in a sedentary society

final design

design implementation



construction A week of design revisions granted the time to organize the materials necessary to construct my design. I procured a sheet of expanded PVC foam-board

base construction seat frame assembly leg forming

and poplar hardwood.


part two

base construction The base would be mocked-up from CNC’ed PVC Foam-board then thermoformed over a model curve. The base feet were formed from layers of poplar, CNC’ed curve to match the base-foot curve and then hand sanded to their shapes. Eligious Bronze in Kansas City assisted in the aluminum casting and attachment of the bas feet.


Rërgonomics reconditioning seating in a sedentary society

base construction



part two


RĂŤrgonomics reconditioning seating in a sedentary society

base construction



part two

seat frame assembly The establishment of a strong, maneuverable seat frame became essential to the utility of the design. The seat pan would rotate around the skateboard truck axels whilst bracing the lumbar support. The whole construction would then rotate around the axis created by the ball-and-socket located inside the truck.


RĂŤrgonomics reconditioning seating in a sedentary society

seat frame assembly



part two


RĂŤrgonomics reconditioning seating in a sedentary society

seat frame assembly



part two

leg forming The two interacting legs achieve the support of the seat frame by connections made between the base and carriage. Similar in their likeness, the legs have been rotated on center and the arm profile twinned. Height modification is performed by pivoting the carriage pins in a zigzag motion in the arms.


RĂŤrgonomics reconditioning seating in a sedentary society

leg forming




conclusions Overall I am satisfied with the completion of this iteration. I have tested the mechanics that could achieve the interactive seat pan that could alleviate the stresses of sitting. In future prototypes, I would address the size and shape of the seat along with placement of lumbar support. The width of the seat prohibits the chair from rotating completely around the truck axis, as it should. This limitation holds back the potential maneuverability of the chair.











refurbished office chairs: php?cat=seating&type=task Embody Diagram: Caster Diagram: Anti-Fatigue Mat: Yoga Mat: news/2010/12/30/1293685834_img1.jpg OSHA images: components_chair.html Skateboard Truck: Vibration Dampening Impact Gloves: VibrationDampening_PalmCoated_Glove_P505.html Dr. Scholl’s Podiatrist in a Box: index.jspa Little-Big Office Chair: Float Desik Chair: All other images courtesy of Corbis free-stock photography or are my own property





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Rergonomics: Reconditioning seating in a static society  

By questioning the need for standard office chair components, dynamism in design and function can be achieved and could possibly change the...

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