ContributionOffice Chair Design for Notebook PC Work, by Hiroyuki ISHIKURA & Nobutoshi YAMAZAKI. Desk sharing in offices has become recently a trend due to the wide spread use of notebook computers. However, they are not always comfortable to use either for reading or typing. We measured the most suitable seating conditions for working with notebook computers. Within the range of heights from the 5th percentile of young females to the 95th percentile of young males, the following optimal conditions were determined. The angles of the keyboard, lower backrest, upper backrest and seat are 10, 68, 79and 10, respectively. The depth of the middle part is shortened to 354 mm for short user. The depths of both outside sections are lengthened to 378 mm, with inclined lateral supportsmaximum angle 35for tall user. To allow the display to be comfortably read, the seat height must be 350410 mm, which is lower than that for conventional office chairs. Evaluations showed that when using this prototype seat in a working environment for 40 minutes, muscle activities in the shoulder and back, and leg swelling were reduced to those when using a conventional office chair, without any decrease in work efficiency. Also, forward tilting of the head decreased by 9and the shoulder elevation was improved. PC PC 595PC PC1068 7910 260 mm354 mm378 mm 35350410 mm 40PC 9 PC 1 PC 1,2 PC 3 4 20128222013311 Graduate School of Science and Technology, Keio University Department of Mechanical Engineerng, Faculty of Science and Technology, Keio University 5 6 700 mmpc PC 2 1 4-2 n8-13 VMC5243L 54
55 7 40 mm25 2 6 700 mm PC PC Epson Endeavor NT2850330 mm288 mm 30 mm 3 I II4 1FQR 5 mm II 34 8 1 Tab. 1 Characteristics of participants. 2 Fig. 2 Adjustable experimental chair. 1 Fig. 1 Definition of measuring point.
II PC 3 Fig. 3 Effect on the initial support line. 4 Fig. 4 Experimental overview. 5 Fig. 5 Definition of length and angle of seat shape. 8 513 16 40 3 3-1PC PC6 10 18 9 15 5 71 10 PC10 3-2 7 N 37922 mm 75 95 10 355 408 mmn 720 mm 288323 mm ϕ θ 6 Fig. 6 Neck posture. ϕ θ 56
y x 7 Fig. 7 Seat height. 10 Fig. 10 Front bending angle. 8 Fig. 8 Seat shape. y x 10 30 mm PC JIS700 mm 3-3 9 Fig. 9 Seat angle. 8 9 1 11 Fig. 11 Side support base distance. 37025 mm 174441 mm92727 mm 39111 mm164860 mm 89133 mm 6 910 10 10 2 390 mm 354 mm 378 mm 3-4 11 57
12 180 mm35 262 0 100 mm 12 Fig. 12 Side support angle. 13 Fig. 13 Side support top distance. 95 10 351 mm13 470 mm 14 3-5 6075 6815 M 15 Fig. 15 Individual difference of backrest shape. 14 Fig. 14 Side support and sagittal shape. 16 Fig. 16 Backrest length. 58
16 95 10 603 mm17 50 17 Fig. 17 Most depressed point position of the chest. 18 Fig. 18 Upper backrest angle. 10 484 mm 18 6811 19 4 4-1 20a 10 mm 353 kg/m 3 700 mm10 PC PC20b 4-2 14-28 19 Fig. 19 Proposed seat shape. 20 Fig. 20 Experimental condition for design evaluation. 2 Tab. 2 Comparison of working amount. 59
22 Fig. 22 Comparison of muscle activities. 21 Fig. 21 Example of sitting posture and pressure. WordExcel20 20 2Word Excel 2t 4-3 14-3 PC5 PC2 VMC5243L BIGMAT 21 119 167 020 9 550680 mm 358410 mm 21 118 5 3 kpa73 kpa205 kpa 227 kpa 4-4 14-43 S&MEBiolog DL-3000 ** ** 1000 Hz 152 15 5 22 971 125 26 4-5 23 Fig. 23 Leg swelling. 7 8 14-55 8 4-2PC1 BI 8 BI BI 2t23 40BI 35 60
24 Fig. 24 Pelvis posture changing. 291615 mm48.5 kg 90 PC 5 PC10 PC 40 25 PC Fig. 25 Practical proto-type of notebook PC chair. 4-6 14-63 ATR-PromotionsWAA-010 PC 24 21 4-7 1478 20 5 135 3 251140 1715 mm67.5 kg4 1,,,,,, VDT,, 48, 7-14, 2006. 2,,,,,, VDT,, 46, 201-212, 2004. 3 Saito S, Miyao M, Kondo T, Sakakibara H, Toyoshima HErgonomic Evaluation of Working Posture of VDT Operation Using Personal Computer with Flat Panel Display, Industrial Health, 35, 264-270, 1997. 4 Asundi K, Odell D, Luce A, Dennerlein J TNotebook computer use on a desk, lap and lap supporteffects on posture, performance and comfort, Ergonomics, 531, 74-82, 2010. 5, VDT,, 37, 390-391, 2001. 6,,, 481, 27-34, 2012. 7,,, 434, 219-227, 2007. 8,, VDT,, 435, 252-260, 2007. 9 VDT,, 23, 58-59, 1987. 10,,, 1996. 61