CHAIR HAVING AN ADJUSTABLE BACKREST FOR SPINAL PROTECTION

摘要

The present invention relates to a chair of which the backrest can be adjusted, and to a chair having an adjustable backrest for spinal protection, in which the inside of a backrest structure is provided with an auxiliary backrest for protecting the lumbar vertebrae, and a rack-and-pinion structure is employed in the backrest and the auxiliary backrest in such a way that as the backrest slides vertically the auxiliary backrest also slides vertically by the same ratio such that the backrest and auxiliary backrest can be used extendably and contractably and are adjusted appropriately to match the seated 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.