Research On Man Machine Relationship Of VDT Office Working System

Along with the gradual popularization of computerized office working, the problem on sub-health what was always troubled clerical employees is increasingly serious. Since half century ago, ergonomics research has played an irreplaceable role in constructing clerical employees' labour safety and health prevention mechanism, and theoretical research on healthy sitting posture obtained considerable progress.However, the price of healthy office chair based on the newest ergonomics technology is often expensive, it has surpassed the general employer's withstanding scope, and most manufactures have technical barrier to product healthy chairs; In the market, ordinary work chairs are difficult to comply with the dynamic demand during VDT work,and they are even cannot provide good body support in the actual work.Therefore, it has an important practical significance for the study on how to realize a kind of office system which is effective&healthy for office staffs and cheap&practical for enterprises, that finding out the relationship between VDT office working system and healthy sitting posture. Around this problem, this subject took investigated and experiment as the main methods for the systematic study on VDT office staffs' sitting behavior and health.(1) The investigation in this paper contains two stages.①The first stage was to investigate the sub-heath statement of the VDT clerical employees in the form of questionnaire based on the internet. There are 192 samples in total, and 181 of them are valid samples. The result revealed that the ratio of the sub-health of respondents up to the 46.4% according to the standard that "There are four physical indexs' evaluation scores equal or greater than four at the same time". Due to the reason that this research is specific to the sub-health on physiology indexs, the result is a little lower than that of other institutes.②The second stage aimed at the working conditions of the VDT clerical employees. The investigation conducted by the ways of fulfilling the questionnaires and tracking studies. The questionnaire specifically included four modules, they respectively are the physical discomfort status of the VDT office stuffs, the subjective evaluation of factors which influent the occupation health, the evaluation of the office devices' usability, and the characteristics of the office behavior.200 questionnaires were sent out and 154 of them were retrieved including 145 available questionnaires, the rate of the effective recovery is 72.5%.The research about the physical discomfort body parts showed that:the most serious physical discomfort parts are the neck, shoulder portions, eyes, waists, the back, and the hip, then are the parts of the right upper limbs. What was more, the discomfort phenomenon especially in the parts of the neck and shoulder portions varies in genders:the degree of the discomfort of the females was always greater than the males.Factor analysis of the occupational health influencing factors indicates that, the contribution rate of accumulative total of variance of the office devices was 60.6%, which threatened the occupational health mostly.The evaluation of the usability shows that the used office equipments, could basically satisfied the users' expectations. The research about the sitting posture behavior indicated that some of the arrangement of the mouth, keyboards and the displays were unreasonable, the wrongful sitting posture and interaction between human and machines were ubiquitous. Moreover, some of the behaviors were related to the indices of the physical discomforts.(2) The experiment in this paper consisted of 3 aspects.ExperimentⅠwas to evaluate the common sitting postures subjectively and objectively. Result shows that:under the experiments, the postures of "c-middle-half","c-front-deep","c-middle-deep" are reasonable to the males while the "c-front-half","s-back-deep","c-middle-half" are reasonable to the females. The body pressure distribution between buttocks and the thigh of females generally unreasonable than males.("c","s" means body curvature;"front","middle","back" means body tilt direction; "half","deep" stands for the size of the contact area between hip and seat surface.)ExperimentⅡmainly investigated the influence of the office equipments on the occupational health. The result shows that the arrangement of the VDT devices affects the VDT sitting posture and health directly; when the dimensions of the VDT office system cannot meet the requirements of work, respondents' first choose were always the suitability of the seat height. Meanwhile, not only when displays were too small to cause the visual fatigue easily but also when displays were too big. When the displays were too small, the respondents would adjust the sitting postures frequently, and when the displays were too big, the respondents would seldom adjust the sitting postures.ExperimentⅢmainly researched into the effect of the seat slope and the included angle contained by trunk and thigh on maintaining a healthy sitting posture. The result shows that compared to other experiments'level, when under conditions that the seat tilted backward 5°while the angle between the trunk and the thigh was 115°, the seat tilted forward 10°while the angle between the trunk and the thigh was 100°, the total subjective evaluations of the respondents were the best while the distribution of the body pressure is also the best.Finally, based on the problems and conclusions from the investigation and experiment, this paper designed a set of healthy VDT office system on the guide of WSR system methodology. At the same time, this paper discussed healthy design method of VDT office system and design ethics problems of modern office form, and advanced that we should give more consideration to the human body measure, behavior demand, work efficiency and occupation health.