Why Are Office Chairs Designed to Recline?
Why Are Office Chairs Designed to Recline? The reason office chairs are designed to tilt backward is for ergonomic considerations. When we sit in a chair, there is a natural
Since 2005, we have served many customers who manufacture chairs and provided them with the core chair tilt mechanisms.
The comfortable structure of the chair is a common topic for us. And we suggest that the tilting angle of the chair back adjusted by the tilt mechanism should not exceed 115 °. Such a seat setting is the best for the users, and the users still can keep healthy even they sit on an office chair for a long time.
Let me introduce Shi Zhenyu, a famous chair designer. He told us how he designed the comfortable chair.
The design of a good chair must take comfort and health as the primary goal. However, he can’t define the general comfort. So in order to design a best office chair in China, Mr. Shi went to the Xiehe Hospital to ask doctors about the concept of comfort. In this way, he understood the standard: the spine kept in a natural state will be comfortable.
And we can know from his research that the seat back tilt adjusted by the chair tilt mechanism should be no more than 115 degrees, which is very important for the user’s health.
Through research, it is found that the design of most furniture puts comfort as the first priority, while health is the second one.
Only the design of office chairs and beds must take health as the first appeal, and comfort the second. Because for the office workers, one-third of their time is spent sitting in an office chair. Sitting for a long time is depleted to the health of the human body.
Therefore, the primary task of chair designers is to design ergonomic chairs to ensure human health. Their research on the healthy seat design is also a kind of care and maintenance of human rights.
The same is true for the bed. While for the other kinds of furniture, their application time is not so much, and people can constantly change postures on them to maintain comfort.
Keeping the lumbar spine and pelvis straight is the natural state of the spine.
The human spine is composed of cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacrum and coccyx.
When sitting, the lumbar spine transmits the force to the pelvis, and then from the ischium under the hip bone to the seat surface. At this time, the backrest of the office chair forms a linkage relationship with the human lumbar spine and pelvis.
This is the connection relationship between the pelvis and the spine when the human body is active.
When the body is active, the verticality of the pelvis and the spine can make the pressure on the human intervertebral disc and the pressure distribution of each segment of the spine in the best state. It can reduce the probability of lumbar disc herniation due to prolonged sitting, so as to keep healthy.
Knowing from the video, pictures, and slice studies, it is preliminarily found that in various angles of sitting postures,
After the establishment of the 115° standard, the A-ONE design team led by Mr. Shi Zhenyu further conducted research on the relationship between human body and chair activities.
The tilt movement of the human body is the joint movement of the knee bone, femur and scapula with the ankle bone as the fixed point. They depicted the linkage form of the ankle bone, knee bone, femur, and scapula in a ratio of 1:5.
Based on this, they obtained the basic size range and movement mode of the seat surface, seat cushion and backrest adjustment of the human body during tilting activities.
The A-ONE team spent over a year on such a picture. This picture is about the synchronized tilting and it is drawn with a 1:5 ratio. It shows the tilting angle of the human body in a sitting state. Besides, it also specifies the parameters that should be the design goals of the office chair:
Human form: adopting the German man-machine standard DIN95%.
*Note:
Study drawings of human sitting activities and chair activities range and methods ( from Decor Magazine)
In order to adapt to DIN5% of people, the following points must be met:
Only the spine and pelvis in various sitting positions are consistent, can it be in a comfortable and healthy state.
Research on Synchronous Inclination Activities ( from Decor Magazine)
The design and manufacture of our NT series tilt mechanism is based on the principle discovered by Mr. Shi Zhenyu: The angle of about 115° formed by the reclining of the sitting person’s torso and his thigh is the maximum value that can maintain the verticality of the pelvis and the spine.
The starting and rear angle of the tilt mechanism should be between 85 degrees and 115 degrees. Then, the spine and the pelvis can be kept perpendicular to the pelvis as much as possible, so that the seater can obtain the greatest comfort.
A research drawing of the working principle of the chair core mechanism. ( from Decor Magazine)
Research and development of a movement tilt mechanism with independent intellectual property rights
Please check our chair tilt mechanisms of the NT series:
In addition, in the above data from the Shi Zhenyu’s research team, we can also know that in order to adapt to DIN5% of the population, the seat back should be have an adjustment of more than 70 mm.
Another highlight of our NT series tilt mechanisms is that the height of the seat back can be adjusted independently. It is anther kind of user-friendly design for seats of different heights.
For the chairs of different styles, we also provide various types of BACK BAR.
If you are also designing a new office or medical chair, please also consider “115° principle”. Such a chair design is the best for users.
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