Chair

A chair comprising:

• a seat, a base support and a backrest, wherein the seat is pivotably mounted on the base support and the backrest is pivotably mounted on the seat;
• a first spring system provided between the base support and the seat, and a second spring system provided between the seat and the backrest;
• wherein the pivoting movement of the backrest in relation to the seat is separate from the pivoting movement of the seat in relation to the base support;
• first and second adjusting means for respectively adjusting a spring behavior of the first and second spring systems so that the pivotability of the seat in relation to the base support and the pivotability of the backrest in relation to the seat can be adapted to different requirements,
• said first adjusting means for adjusting the spring behavior of the first spring system and said second adjusting means for adjusting the spring behavior of the second spring system being coupled together in such a way that an adjustment of the spring behavior of one of the first and second spring systems automatically effects adjustment of the spring behavior of the other of the first and second spring systems;
• and
• wherein the seat is pivotable about a first articulation axis and the backrest is pivotable about a second articulation axis, with the two articulation axes being arranged so as to be displaceable relative to one another, and
• wherein the first and second spring systems and the first and second adjusting means for adjusting the spring behavior of the two spring systems are adapted to one another so that, even for users of different weights, substantially the same synchronous relationship between the inclination of the seat and the inclination of the backrest is rendered possible.

A chair comprising:

• a seat, a base support and a backrest, wherein the seat is pivotably mounted on the base support and the backrest is pivotably mounted on the seat;
• a first spring system provided between the base support and the seat, and a second spring system provided between the seat and the backrest;
• wherein the pivoting movement of the backrest in relation to the seat is separate from the pivoting movement of the seat in relation to the base support;
• first and second adjusting means for respectively adjusting a spring behavior of the first and second spring systems so that the pivotability of the seat in relation to the base support and the pivotability of the backrest in relation to the seat can be adapted to different requirements,
• said first adjusting means for adjusting the spring behavior of the first spring system and said second adjusting means for adjusting the spring behavior of the second spring system being coupled together in such a way that an adjustment of the spring behavior of one of the first and second spring systems automatically effects adjustment of the spring behavior of the other of the first and second spring systems;
• and
• wherein the seat is pivotable about a first articulation axis and the backrest is pivotable about a second articulation axis, with the two articulation axes being arranged so as to be displaceable relative to one another,
• wherein the first spring system has a first spring member and a first spring mechanism co-operating with the first spring member, and
• wherein the first and second adjusting means for adjusting the spring behavior of the first and second spring systems are formed by devices which adjust different spring characteristics of the respective first and second spring systems, wherein the first and second spring systems are formed so that the respective spring member is unloaded in the normal position of the chair, and also so that for users of different weights, and in this unloaded starting position of the spring member, all the adjustable spring characteristics of the spring system have a common origin.