King Saud University. College of Engineering. IE 341: Human Factors

Transcription

1 King Saud University Cllege f Engineering IE 341: Human Factrs Fall 2015 (1 st Sem H) Applied Anthrpmetry, Wrk-Space Design Part II - Design f Wrk Surfaces (Chapter 13) Prepared by: Ahmed M. El-Sherbeeny, PhD 1

2 Lessn Overview Design f Wrk Surfaces Hrizntal Wrk Surface Area Wrk-Surface Height Seated Standing 2

3 Design f Wrk Surfaces Imprtant use f anthrpmetric data: wrk space Wrk-space envelpe (Def n ): 3-D space within which individual wrks Invlves mstly space where hands can mve Within envelpe, design decisins must be made abut features f the wrkspace, e.g. lcatin and design f benches, desks, tables, and cntrl panels Discussed here samples f wrk surfaces: hrizntal, vertical 3

4 Hrizntal Wrk Surface Area This is area used by: Seated wrker Sit-stand wrker Area shuld allw fr manual activities within cnvenient arm reach (what is cnvenient?) Research n hrizntal wrk surface area: Barnes (1963) and Farley (1955): Shwn in next slide (carefully examine dimensins) Nrmal Area: area cnveniently reached by frearm (while upper arm hangs in natural psitin) Maximum Area: area reached by extending the arm frm the shulder Squires (1956): suggests ptimal area : takes int accunt dynamic interactin f frearm mvement as the elbw is als mving (als shwn next slide) 4

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6 Cnt. Hrizntal Wrk Surface Area Cnt. Research n hriz. wrk surface area Squires (ptimal) area vs. Farley area (nrmal-max.) Squires area mre shallw but cvers mre area Squires area requires less frearm extensin minimal stress n elbw jint Ayub (1973): suggests ptimal wrk area: apprx. 25 * 25 cm (see next slide; nte similarities) 10 cm frm the table edge bdy mid-line crssing at the middle f the area Surce [Pheasant textbk]; 6

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8 Cnt. Hrizntal Wrk Surface Area Cnt. Research n hriz. wrk surface area Bridger (1988): slanted wrking surface is better: trunk: less mtin upright- (vs. hrizntal) neck: less bending als less fatigue and discmfrt slant (here) = 15º slant (ther research): 12º and 24º applicatins: Visual tasks (e.g. reading) Can yu name any disadvantages f slanted surfaces? 8

9 Wrk-Surface Height Height f wrk surface: Can cause backaches, neck aches, shulder pains T lw back is bent ver t much T high shulders raised ver relaxed psture discmfrt in shulder and neck Wrk-surface height vs. wrking height Wrk-surface height: height f upper surface f table, bench, desk, etc. measured frm the flr fr slanted surface: need height f frnt edge + angle Wrking height Depends n what peratr is wrking n e.g. writing paper wrking ht. = wrk-surface ht. e.g. writing n keybard wrking ht. = ht.: asdfg hw abut when washing vegetable in a sink? 9

10 Wrk-Surface Height: 1. Seated Seated Wrk-Surface: Height & Arm Psture Wrk surface height is affected by: Arm psture Seat height Thickness f the wrk surface (which affects?) Thickness f the thighs As wrk-surface height Mre relaxed psture f upper arms (@ wrking ht.) Elbws are at 90º (with respect t wrking ht.) Wrists are straight Overall cmfrtable wrking (shulders, spine, etc.) Beneficial fr repetitive tasks (e.g. typing, assembly) Cmmn desk wrk-surface heights 76 cm (30 in) Research: recmmend reductin t 72 cm, 68.6 cm 10

11 Cnt. Wrk-Surface Height: 1. Seated Seated Wrk-Surface: Height & Thigh Clearance Thigh clearance: Determined by dist. bet. seat & wrk surface bttm Design here fr max, min, average, adjustable? Nn-adjustable height wrk surface ANSI: 26.2 in (66.5 cm) as min. ht. f bttm Small users raise seat s elbws are at 90º t wrk surface feet dn t tuch flr ft rest is needed t supprt feet r use adjustable-height wrk surface Adjustable-height wrk surface ANSI: cm fr bttm f wrk surface 11

12 Cnt. Wrk-Surface Height: 1. Seated General Principles fr Seated Wrk Surfaces: 1. Best t find wrk surfaces with adjustable height (e.g. adjustable cmputer tables) 2. Best if wrk surface is such that elbw height = wrking height 3. Wrk surface shuld prvide enugh clearance fr peple with thick thighs 4. Recmm. seated wrk surface ht. fr different tasks: 12

13 Wrk-Surface Height: 2. Standing Factrs gverning standing wrk-surface ht Elbw height Type f wrk Type f wrk vs. elbw height (next slide): Light and heavy wrk: wrk-surface height: belw elbw height Precisin wrk: wrk-surface height: slightly abve elbw height Reasn: t supprt elbw while perfrming wrk but recmmended: sitting dwn fr precisin wrk Fixed vs. adjustable standing wrk surface height Fixed: designed fr max. (i.e. tallest) users Shrter users: either use a platfrm t accunt fr height difference r use adjustable ht. (e.g. electric, manual, hydraulic) 13

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15 Cnt Wrk-Surface Height: 2. Standing Other recmmendatins: Wrk height: t high shulders & upper limbs raised fatigue, strain n shulder muscles Wrk height: t lw trunk, neck, head: inclined frward stress n spine Recmmended hts. fr different tasks: belw fr fixed vs. adjustable ht (and fr male, female) 15