Abstract:
Objective in order to use the family comfortable health in the office. Methods according to the characteristics of furniture design, the human body in the use of the process of action and posture in which to consider, the person and the chair as a system to study, and find out the design basis. Results the body in the process of using the table and chairs, the change of action posture, need to make changes to the appropriate use of tables and chairs. Conclusion the data obtained from the measurement and the calculation method are both real and effective, which provide the basis for the design of tables and chairs in the future.
key word：
Office furniture system for human factors engineering
No. in the middle of the chart: TB472
Document identification code: A
Article number: 1003-0069 (2015) 06-0130-02
Office computer application in modern society has been more and more widely, but the use of computers also give users bring a lot of problems, especially in the use of process in the user will feel tired, serious and even lead to damage to the body of the user. So a reasonable design and furniture is very necessary. After nearly a decade of furniture design case access, summed up the following conclusions and improvement of the chair and the design has been studied for many years, but the user when in use will still often feel physical fatigue and discomfort, especially in the use of computers. The reason is that a taste only the chairs of static size of research and design is not comprehensive, users in the use of tables and chairs, posture and movement is changing, only tables and chairs and body movements and gestures, the user can in the use process of health and safety and comfort.
1 chair size
By (see Figure 1), when the body is in a sitting position, the support points are the head, neck, back, hip, knee, ankle, foot, elbow, hand, and so on. The supporting points are acting on the back seat, the seat surface, the arm rest, the head, the back seat, the back seat and the back seat.
The seat surface is composed of a high seat, a base width, a base depth, a reference point and a seat surface inclination angle. Body in the role on the seat surface, sciatic node point on the seat surface of said as a reference point, the datum point is around the body of the popliteal fossa of rotation of a circular arc, so it is not a fixed value, change with the height variation of seat surface inclination angle and knee popliteal fossa, through a Formula M = Ml-Lxsin can reference point height m is obtained, which ml is sitting under the knee popliteal height, l thigh length, a is seat surface inclination.
1.2 high
The vertical distance between the front end of the seat and the ground is high. According to the ergonomics of the posture and seating design of investigation and study that high requirements: sitting thigh level, natural sagging leg put on the ground; II knee popliteal not subject to pressure. The hip and knee popliteal fossa behind the thigh muscle by support of the seat surface. By the formula can get L=L1+25-6-10 (mm) where L is high, the value of Ll for the lower leg and foot high value, 25mm for shoes correction, 6mm for the next fitting amount.
1.3 seat width
The allowance of free upper limb is 60mm, +60mm percentile shoulder width under the premise of a wide survey of comfortable seat width guarantee for the buttocks support but also with the user to change position, through the GB \/ T 10000-1988 Chinese adult body size and female hip width is generally greater than that of the male, so the block width = percent to 95 percent of the women buttock width + clothes correction in here, it is worth attention is that such a situation that is in no handrails, and the arm, in order to let the user more free and comfortable, the data of the human body shoulder width, because men more than women, so the seat width = 95 male shoulder + clothes correction which activities.
1.4 deep
Seat depth refers to the front end of the seat to the back of the distance. Deep must satisfy the following several points: the buttocks are fully supported; the back is fully supported; the front end of the leg and the seat to maintain a certain distance, so that the leg can be free activities, to avoid compression leg.
Seat depth = thigh length of a reserved length (usually 60mm).
1.5 seat angle
By investigating and studying the dip angle of the seat, the seat surface needs to move forward, so that the body can not only avoid sliding down, but also ensure the human body and the back of the joint, and share the pressure, increase the comfort. Worthy of note is the angle should not be too large, angle increases the pressure of the thigh, the user thigh compression feel discomfort, and increase the bending degree of the vertebra, increased spine loss. The survey of 14774-1993 GB\/T "work chair general Ergonomics requirements" dip is generally set at 0. ~ 5. , the ideal value is 3. - 4..
1.7 arm
Seat handrail role has the following several points: (1) reduce the arms of fatigue on my arms to support the role of, and reduce the shoulder the burden of; (2) in human by posture change is in the process of standing play a supporting role, as a support and keep user role balance of the body. The parameters of the arm rest are composed of the height, the width and the length of the arm.
By referring to the GB\/T14774-1993, seat general Ergonomics requirements, height of handrail, in general, for slightly higher than the body posture of the elbow, and recommended values 230mm + 20mm, armrest width generally set to hand in the natural bending can grip, recommended values between 65mm and 70mm. The length of the arm is generally set to start in the body's natural sitting posture can help the front end of the hand grip can be, while the elbow left after the activity space.
Arm length = forearm length + hand + reserved space
2 table size
2.1 desktop work area
Squires, an American scholar, through the study of the proposed calculation method of upper level work area (see Figure 2) light area squires of schematic diagram and the dark part of the is in before the squires of rough sketch map of regional. First of all, to determine the right side of the body of a few basic points, in this note is the measurement of the level of work when all the points and angles are based on the human body. Shoulder joint position point E, the middle finger finger end point P and the trajectory of the end position for Q, human overlooking the medial axis points a, elbow position C, usually study to point C is the starting point at the elbows close to the body side of the position, and elbows to reach the end point trajectory set D, then elbow trajectories in human overlooking the view see nearly a quarter of the arc CD, the angle measuring arc CD tangents and forearm CP 42. At the same time, the PQ curve of the moving trajectory of the right hand is determined by the following equation: e+M2 cos[65 X=Mlcos. + (73. \/90. 0 Y=M2 cos e+M2sin[65]. + (73. \/90. Theta], which Ml=EC (overlooking the spatial distance is not the distance), M2=CP (overlooking the spatial distance is not the distance), theta angle CP forearm on the work surface projection and work table front. For upper limb vertical working face, the working area is not so complicated as defined by the level of the upper limb, generally for the shoulder joint as the axis, arm EP as the radius of the spherical surface. For the lower limbs, the range of activities is mainly concentrated in the vertical flexion and extension of the leg forward 35. And backward 20. between。
2.2 desktop height
For the height of the desktop, mainly due to human human vision and sit high, after investigation found that human eye level down 15. Is the most natural and comfortable state of the human body, the main point of view of writing and reading in 45. To 60. Between, while the best area of the display device is in the 0. To 35. between。 305mm to 460mm of the distance is ideal for adults, 406mm is the minimum reading distance, and the ideal distance to watch the display is 457mm to 610mm. The ideal requirement for the writing and reading of the angle between the desktop and the arm is 10. To 15.. Desktop height can be obtained by the formula H=H1+H2\/3-20 (mm), where the Hl is high, H2 is high. And when using the keyboard require desktop height and human elbow flat. So through the research can draw desktop keyboard height is H=H1+H2, which HL high sitting elbow (according to the height of the chair), H2 for correction (summer and winter clothing thickness difference, etc.). 2.3 desktop width
In this study is effective working area of the width of the operation on the seat, so study first calculates table effective width L=L1+L2 * 2 the L1 shoulder width, L2 is the length of the arm function. For the efficient width of the desktop width we use the American scholar J Quarle's formula:
H=Hlx2, Hl=Ml cos +M2 cos[65. + (73. \/90. Theta theta =90]. In which H is the efficient width of the table, including Ml=EC (the distance is not the space), M2=CP (the distance is not the space distance).
2.4 desktop depth
This research is operated on the seat effective work area depth, effective depth L=Ll-L2. where L1 is the length of the arm function, L2 shoulder to distance from the edge of the table,, we continue to use the formula T=T1-T2 squires, an American scholar, T1 = Y=M2cos theta +M2sin[65. + (73. \/90. Theta], where t for the desktop, depth, M2=CP (overlooking the spatial distance is not the distance), theta angle CP forearm on the work surface projection and work table front, T2 for the shoulder to distance from the edge of the table.
2.5 desktop dip
In the desk research writing or reading, and ground level desktop tends to increase the bending degree of the cervical we, making the body feel discomfort, but blindly increase the angle will lead to detachment of articles on a table, so after the GB\/T14774-1993, seat general class of Ergonomics requirements review and study, considering friction relation between human health and objects and desktop obtained desktop inclination of the ideal value of 10. To 12. between。
2.6 lower limb space under the table
Studies took a university table space (see Figure 2) shows, designers in order to secure the table at the bottom and on the right side of the chassis slot and in its lower part with a cross beams, the design seriously restricted the user free lower limb, bring discomfort to the user. Through the study, it is concluded that the formula D D=D1+D2 is the height of the height of the legs, Dl for the sitting thigh thickness, D2 for the lower leg and foot high, for the lower limb activities mainly concentrated in the legs of the vertical flexion and extension forward 35. And backward 20. In between, we make a reasonable design of lower limb space under the table.
3 conclusion
Chairs and tables for the users need is comfortable and efficient, if tables and chairs and manual adjustment project too much, but will increase the user's strangeness and sense of confusion, so the product to according to the needs of trade-offs, in the world the no perfect thing, only the most appropriate things. When designing, the project can be adjusted to be simple and easy to operate, as far as possible to achieve automation, avoid unnecessary trouble to the user.
Products, people and the environment has never been isolated, is to cooperate with each other, the study of the three as a system to study, through the study we can sum up the following points:
The research object and starting point is not the product itself, but the research object and the starting point. Products need to meet the needs and characteristics of people.
The research of human factors engineering should have scientific justice.
Human behavior is instinctive, but to be clear, the instinct is not necessarily correct, not necessarily the most reasonable, so at the same time the study should have a dialectical thinking, the people to measure and choose. Researchers should take the initiative to bring the right results to the public and guide the public.
3 people, products and environment is an organic system, mutual promotion and mutual coordination, there is no absolute who depend on who, who obey to whom, the purpose of the study is the system to adjust to the optimization, to make the system more healthy, more secure, more comfortable and make the system efficiency is maximized.