Patent ID: 7401858
Filing Date: 2008-07-22
Classification: A47C

Abstract:
1. A chair having a seat, a backrest and support legs, the backrest being automatically adjustable for thereby preventing various backbone-related diseases, comprising: upper, intermediate and lower plates installed between the seat and the support legs at a certain interval therebetween in upper and lower directions; a hydraulic pressure-applying means installed between the intermediate plate and the lower plate in such a manner that an elastic operation is achieved in the upper and lower directions, the hydraulic pressure-applying means including a hydraulic pressure-applying cylinder operating in such a manner that when a user sits on a chair, the intermediate plate is elastically compressed by weight of the user, and a hydraulic pressure is applied to a reciprocation operation cylinder installed between the upper plate and the intermediate plate, and when the user gets up from the seat, the compressed state of the intermediate plate is recovered to its original state, so that the hydraulic pressure supplied to the reciprocation operation cylinder is applied to the hydraulic pressure applying cylinder; a guide box installed between the upper plate and the intermediate plate and horizontally installed on an upper surface of the intermediate plate in forward and backward directions; a backrest moving means including: