Abstract: A working chair with adjustable backrest support pre-set tension is described, in which a swiveling backrest support is positioned on a seat part, the backrest support being prestressed against the back of the user with a manually adjustable pre-set tension of an energy storing device. The front end of the energy storing device is rotatably mounted on a free, swiveling end of a guide bar close to the seat edge, and the rear end of the energy storing device is coupled to a free, swiveling end of the backrest support at a contact point which is designed to be adjustable and detectable.

Abstract: A working chair with adjustable backrest support pre-set tension is described, in which a swiveling backrest support is positioned on a seat part, the backrest support being prestressed against the back of the user with a manually adjustable pre-set tension of an energy storing device. The front end of the energy storing device is rotatably mounted on a free, swiveling end of a guide bar close to the seat edge, and the rear end of the energy storing device is coupled to a free, swiveling end of the backrest support at a contact point which is designed to be adjustable and detectable.

Abstract: A work or office chair having a seat shell which is pivotably arranged on a height-adjustable seat carrier, characterized by the seat shell being spring loaded to oppose tilting of the seat shell from a raised position towards a tilted, lower position. The chair includes a fixing arrangement for fixing the chair in specific tilted positions. One improvement is a spring arrangement for supporting the chair and a toggle arrangement coacting with the spring arrangement for opposing tilting of the chair with the springs of the toggle arrangement and the supporting spring coacting to require a substantial force to cause initial tilting then followed by a gradual force to cause tilting.

Abstract: The work chair has a seat squab and a backrest which both pivot on a seat carrier in the same direction interdependently. A load element is fitted to the seat carrier which is adjustable over its linear extension by means of a locking mechanism, whereby the load element pivots the seat squab and backrest into position of rest under spring loading.To achieve a relatively large and symmetric spring loading in the smallest space it is foreseen that the load element should consist of two parallel compression springs in between which a hydraulic locking mechanism is fitted whereby one end of the load element is connected by a pivot to the free pivoting part of a lever arm, which forms the backrest-carrying part.