How to design chairs according to ergonomics

Each person's sitting posture is different, but in general they can be divided into three categories. Generally speaking, when you are working, you are sitting forward. When you are relaxing, you are doing it backwards. When you are officially talking, you sit straight. Regardless of the posture, sitting for a long time will have a certain impact on our spine. Therefore, our chairs must be designed according to the characteristics of the human body. So how is the chair designed to achieve the most comfortable state? Xianghe Furniture City official website ()

How to design chairs according to ergonomics

First, sit high

Sitting height refers to the vertical distance from the seat to the ground. Since the seat surface is often inclined backwards, the seat height of the chair is usually the height of the seat as the seat height; if the seat surface is inclined backward or concave, the seat height is the vertical distance from the center of the front seat to the ground.

Appropriate seating height: Keep the thighs horizontal, the calves vertical, and the feet flat on the ground. If the seat height is too high, the two legs will vacate the thigh blood vessels; if it is too low, it will cause physical fatigue. Practice has proved that the appropriate seat height is the calf height to the sole height plus the heel thickness of 25-35mm, and then the activity margin of 10-20mm is subtracted.

Seat height = calf height + heel thickness - proper clearance

The national standard GB 3326-1997 specifies: the seat height is 400-440mm, and the size difference is 10mm.

How to design chairs according to ergonomics

Second, the height of the backrest

The size of the backrest is mainly related to the height from the bottom of the buttocks to the shoulders (determining the height of the backrest) and the width of the shoulders (determining the width of the backrest). The height and width of the backrest of the chair, the maximum height of the backrest can reach 480~630MM, and the maximum width can reach 350~480MM.

Third, the height of the armrest

The height of the armrest should be similar to the vertical distance from the human ischial node to the lower end of the elbow when it is naturally drooping. Practice has proved that the vertical distance from the upper surface of the armrest to the seat surface is preferably 200-250mm. At the same time, the front end of the handrail should be slightly higher. With the change of the inclination angle of the seat surface and the angle of the backrest, the inclination of the handrail is generally 10-20 degrees, and the handrail is preferably within the range of 10 degrees.

How to design chairs according to ergonomics

Fourth, the slope of the sitting surface

When the person is resting, the sitting posture is leaning backwards to support the lumbar vertebrae, so most of the general sitting faces are designed to be inclined backward. The inclination of the seat surface is generally 3 to 5 degrees, and the opposite seat back is also inclined backward.

Five, sit deep

Sitting depth refers to the distance from the front to the back of the chair. The depth of the sitting depth has a great influence on the comfort of the sitting posture. If the chair is deeper than the horizontal length of the thigh, the backrest of the human body will have a large inclination, and the waist lacks the support point and hangs, which aggravates the muscle activity of the waist and causes fatigue; at the same time, the seat is too deep, so that the knee is at the knee Produces numbness and is also not conducive to standing up.

The average length of the thigh in China's sitting posture is 445MM for men and 425MM for women, and then there is a certain distance (about 60MM) from the inside of the knee to ensure that the sitting size is between 380 and 420MM.

How to design chairs according to ergonomics

Sixth, sitting width

The width of the seat surface of the chair is often in the shape of a front width and a narrow shape according to the sitting posture and movement of the person. The width of the front edge of the seat surface is called the front width, and the width of the rear edge is called the back width. The seat width is generally not less than 380mm. For a chair with armrests, it is necessary to consider the support of the human arm. The inner width of the armrest is used as the size of the sitting width, and an appropriate margin is added according to the average shoulder width of the human body. Not less than 460MM, but not too wide, should be based on the comfortable shoulder width of the natural vertical arm.

After the chair meets the ergonomics, if it does not match the table, the same problem will occur. Therefore, the table and the chair should satisfy the ergonomics at the same time, and it must be reasonably matched so that people can use it more comfortable.

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