Patent ID: 8931841
Filing Date: 2015-01-13
Classification: A47C

Abstract:
1. A synchronous mechanism for a chair, comprising: a base unit, a seat support, which is arranged above and moveably on the base unit, a backrest support which is arranged on the base unit so as to be capable of being pivoted about a pivot axis, which is oriented horizontally and in transverse direction of the chair, and a prestressing device, wherein the prestressing device exerts a prestressing force, which acts upwards on the seat support and forwards on the backrest support, and wherein the seat support is connected to the base unit via a coupling mechanism, which provides for the movability of the seat support relative to the base unit, and the coupling mechanism being arranged such that it positively controls the movements of the seat support relative to the base unit such that the seat support can be moved back and forth solely between positions, which are parallel to one another, when the backrest support is fixed, wherein the coupling mechanism encompasses a front joint arrangement which is arranged in a front area of the seat support, and a rear joint arrangement, which is arranged in a rear area of the seat support, wherein the front joint arrangement and the rear joint arrangement are coupled to one another mechanically such that a movement of the front joint arrangement effects a movement of the rear joint arrangement and vice versa, wherein each joint arrangement encompasses two joint units, which are arranged spaced apart from one another relative to the transverse direction of the chair, and which are mechanically coupled to one another such that a movement of the one joint unit effects a movement of the other joint unit, and wherein each front joint unit comprises an upper element and a lower element, which are connected to one another on one end in an articulated manner via a free first axis, the upper element is connected to the base unit and the seat support in an articulated manner on the other end via a second axis and the lower element is connected to the base unit in an articulated manner on the other end via a third axis, wherein the free first axis, the second axis and the third axis are arranged parallel to and spaced apart from the pivot axis, wherein the second axis is guided in vertical direction on the end side in elongated holes on the base unit, wherein the free first axis is arranged in front of the second axis and the third axis, and wherein the free first axis, the second axis and the third axis of the one front joint unit form the free first axis, the second axis and the third axis of the other front joint unit.