| 摘要 |
The present invention relates to a chair having an adjustable backrest for spinal protection in that an inside of a backrest structure is provided with an auxiliary backrest for protecting a lumbar vertebrae, and a rack and pinion structure is employed in the backrest and the auxiliary backrest in such a manner that the backrest slides vertically and the auxiliary backrest also slides vertically by the same ratio such that the backrest and the auxiliary backrest can be adjusted appropriately and used flexibly to match the sitting height of the person sitting on the seat, thereby making it possible to provide effective protection to the spinal joints of the waist, back and neck of the user.
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