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Design of Fixed, Portable, and Mobile Information Devices
Published in Julie A. Jacko, The Human–Computer Interaction Handbook, 2012
Michael J. Smith, Pascale Carayon
Another important chair feature is armrests. Both pros and cons to the use of armrests at computer workstations have been advanced. On the one hand, some chair armrests can present problems of restricted arm movement, interference with the operation of input devices, pinching of fingers between the armrest and table, restriction of chair movement, such as under the work table, irritation of the arm or elbows due to tissue compression when resting on the armrest, and adoption of awkward postures. Properly designed armrests can overcome the problems mentioned above. Armrests can provide support for resting the arms to prevent or reduce arm, shoulder, and neck fatigue. Removable armrests are an advantage because they provide greater flexibility for individual operator preference. For specific tasks such as using a numeric keypad, a full armrest can be beneficial in supporting the arms. Many chairs have height adjustable armrests that are helpful for operator comfort, and some allow for adjusting the angle of the armrests as well.
OFFICE ERGONOMICS
Published in Charles D. Reese, Office Building Safety and Health, 2004
Armrests on chairs are recommended for most office work except where they interfere with the task. Resting arms on armrests is a very effective way to reduce arm discomforts. Armrests should be sufficiently short and low to allow workers to get close enough to their work surfaces, especially for tasks that require fixed arm postures above the work surface (see Figure 12-2).
Effect of seat back angle on preferred seat pan inclination for the development of highly automated vehicles
Published in Ergonomics, 2023
Xuguang Wang, Cyrille Grébonval, Philippe Beillas
The same reconfigurable experimental seat as the one in our previous studies (Wang et al., 2018, 2019, and 2021) was used. It was composed of four main structural components: a seat back frame, a seat pan, a foot support, and two armrests (Figure 1A). The seatback frame was articulated with the supporting frame around a lateral axis passing through the reference point of the experimental seat (PRC). The backrest was composed of three support panels mounted on the seatback frame. To better approach an actual seat back, two aluminum plates with a thin foam were added on the initial lower and middle supports. They were slightly contoured to better fit the lumbar and dorsal back shapes. For the upper panel, the headrest of an actual airplane seat was fixed. To overcome the limited range of the seat pan, a wooden triangular block was added to the seat pan support so that the seat pan could be inclined from 9 to 45 degrees with respect to the horizontal. The foot support had a rectangular surface on which an office footrest with an inclination angle of 34.6 degrees to the horizontal was added. The footrest was fixed on the foot support whose position was adjustable. Twelve parameters of the experimental seat could be adjusted in this study (Figure 1B). They could be controlled either by an experimenter via a computer or directly by the participants via a tablet. Adjustable features included the forward (x) and vertical (z) positions of the three backrest supports, seat pan, and foot support; as well as the backrest and seat pan inclinations. Two armrests were also used and their positions could be adjusted manually. The foot support, the seat pan, the two armrests, and the three back supports were equipped with force sensors to measure the contact forces in the seat XZ plane. A more detailed description of the experimental seat can be found in Beurier et al. (2017).