Piece of seating furniture with a longitudinal axis above the seating surface

Abstract

Seating furniture having a longitudinal axis above a seating surface. The seating furniture defines a plane of symmetry and includes a lower part, which has a base or is formed therewith in its upper region, and a seating surface which is movably connected to the base by means of a kinematics about a longitudinal axis which lies at least largely above the seating surface, is inclined forwards and downwards by up to 75° (preferably 45°±20°) relative to the horizontal, lies in the plane of symmetry in the rest position and is optionally formed virtually. A restoring device with an energy accumulator is provided between the base and the seating surface, which restoring device exerts a restoring torque on the seating surface when the seating surface is deflected about the longitudinal axis from the rest position.

What is claimed is: 
     
         1 . A piece of seating furniture having a plane of symmetry, comprising:
 a lower part, where the lower part includes a base or is formed with a base in an upper region of the lower part;   a seating surface that is swivelably connected to the base via a kinematics, such that the seating surface is swivelable about a longitudinal axis by means of the kinematics;   wherein when the piece of seating furniture is in a resting position the longitudinal axis lies in the plane of symmetry in an angular range of between 5° in a backward and downward direction and 75° in a forward and downward direction, relative to a horizontal plane;   wherein the longitudinal axis, when considered in a region of a vertical projection P of the seating surface, or optionally when considered in a region of a vertical projection P of the seating surface combined with a rear seating surface part, lies above the seating surface along more than 50% of a length of the vertical projection P; and   further comprising a restoring device with an energy accumulator disposed between the base and the seating surface, the restoring device configured to exert a restoring torque on the seating surface when the seating surface is deflected about the longitudinal axis from the rest position.   
     
     
         2 . The piece of seating furniture of  claim 1 , wherein the restoring torque is between 1.25 Nm/° swivel angle and 20 Nm/° swivel angle about the longitudinal axis. 
     
     
         3 . The piece of seating furniture of  claim 1 , wherein the restoring torque is within a range of 5±10% Nm/° swivel angle. 
     
     
         4 . The piece of seating furniture of  claim 1 , wherein the longitudinal axis is inclined relative to the horizontal plane by no more than 30°. 
     
     
         5 . The piece of seating furniture of  claim 1 , wherein the longitudinal axis is inclined relative to the horizontal plane by no more than 15°. 
     
     
         6 . The piece of seating furniture of  claim 1 , wherein the longitudinal axis in a rear third of the seating surface, optionally in combination with a rear seating surface part, lies substantially at a level of a ninth to a twelfth thoracic vertebra of a user. 
     
     
         7 . The piece of seating furniture of  claim 1 , wherein the longitudinal axis in a rear third of the seating surface, optionally in combination with a rear seating surface part, lies substantially at a level of an eleventh thoracic vertebra of a user. 
     
     
         8 . The piece of seating furniture of  claim 1 , wherein when the piece of seating furniture is in the resting position the longitudinal axis lies in the plane of symmetry in an angular range of between 15° in a forward and downward direction and 75° in a forward and downward direction, relative to the horizontal plane. 
     
     
         9 . The piece of seating furniture of  claim 1 , wherein when the piece of seating furniture is in the resting position the longitudinal axis lies in the plane of symmetry in an angular range of between 25° in a forward and downward direction and 65° in a forward and downward direction, relative to the horizontal plane. 
     
     
         10 . The piece of seating furniture of  claim 1 , wherein when the piece of seating furniture is in the resting position the longitudinal axis lies in the plane of symmetry in an angular range of between 40° in a forward and downward direction and 50° in a forward and downward direction, relative to the horizontal plane. 
     
     
         11 . The piece of seating furniture of  claim 1 , wherein the longitudinal axis is formed virtually. 
     
     
         12 . The piece of seating furniture of  claim 1 , wherein the kinematics of the seating surface is configured to enable a spherical motion about a central point located above the seating surface, and forms the longitudinal axis virtually. 
     
     
         13 . The piece of seating furniture of  claim 12 , wherein the restoring device is swivelably connected to the base at an arm point and to the seating surface at a seating point;
 the arm point is disposed a distance A 0  from the seating point when the piece of seating furniture is in the rest position;   the arm point, the seating point and the central point each lie on a line of action; and   the restoring device includes an energy accumulator that is configured such that an energy of the energy accumulator increases as the distance A 0  increases.   
     
     
         14 . The piece of seating furniture of  claim 13 , wherein the energy accumulator of the restoring device is mounted on the base in a tube;
 the energy accumulator has a form of a spring package that can be changed in its preload by a handle, wherein a threaded rod projects through the spring package and is swivelably connected to a rotary lever by means of a plate,   the rotary lever is swivelably connected to the base at one end about a rotary lever axis; and   the rotary lever is rotatably mounted at its other end about a connection axis with the seating surface via two intermediate members that are arranged in alignment and are rotatable along their longitudinal extent.   
     
     
         15 . The piece of seating furniture of  claim 14 , wherein the rotary lever is rotatably mounted at its other end about a connection axis with the seating surface via a mounting plate. 
     
     
         16 . The piece of seating furniture of  claim 12 , wherein the kinematics is connected to the seating surface via a backrest and a rear seating surface part formed fixedly thereto, and which is connected to the rear seating surface part so as to be swivelable about a horizontal transverse axis, and which is held in its position relative to the rear seating surface part by a supporting kinematics;
 wherein the longitudinal axis runs between a central point and a front, upper region of the support kinematics;   wherein the restoring device uses an elastic deformation of the support kinematics as an energy accumulator and is thus a seating surface accumulator kinematics, and a targeted deformation of the seating surface accumulator kinematics is achieved in that:
 a control arm provided on one side of the seating surface and firmly connected thereto is swivelably connected at an other end about a horizontal bearing axis extending perpendicular to the plane of symmetry and provided on a lower edge of a substantially vertically-arranged squeeze plate; 
 the squeeze plate is swivelably connected at its upper edge about a support axis running parallel to a bearing axis to a front edge of a support plate, a rear edge of which is hinged to the base about an axis running parallel thereto; 
 a pyramid is provided including three rods with a base-fixed base plane and a tip through which the support axis runs; 
 two arms extending laterally outwards extend from a tip of the pyramid in a swivelable manner, the two arms having free ends which are swivelably mounted on the bearing axis; and 
   whereby, when the piece of seating furniture is deflected from the rest position, the control arm, the squeeze plate, and the support plate are elastically deformed in a buckling manner and thus act as energy accumulator and provide the restoring torque.   
     
     
         17 . The piece of seating furniture of  claim 1 , wherein the kinematics is a three-axis kinematics that defines a central point or a central region and forms the longitudinal axis virtually. 
     
     
         18 . The piece of seating furniture of  claim 17 , wherein the restoring device is swivelably connected to the base at an arm point and to the seating surface at a seating point;
 the arm point is disposed a distance A 0  from the seating point when the piece of seating furniture is in the rest position;   the arm point, the seating point and the central point each lie on a line of action; and   the restoring device includes an energy accumulator that is configured such that an energy of the energy accumulator increases as the distance A 0  increases.   
     
     
         19 . The piece of seating furniture of  claim 17 , wherein the energy accumulator of the restoring device is mounted on the base in a tube;
 the energy accumulator has a form of a spring package that can be changed in its preload by a handle, wherein a threaded rod projects through the spring package and is swivelably connected to a rotary lever by means of a plate;   the rotary lever is swivelably connected to the base at one end about a rotary lever axis; and   the rotary lever is rotatably mounted at its other end about a connection axis with the seating surface via two intermediate members that are arranged in alignment and are rotatable along their longitudinal extent.   
     
     
         20 . The piece of seating furniture of  claim 19 , wherein the rotary lever is rotatably mounted at its other end about a connection axis with the seating surface via a mounting plate. 
     
     
         21 . The piece of seating furniture of  claim 17 , wherein the kinematics is connected to the seating surface via a backrest and a rear seating surface part formed fixedly thereto, and which is connected to the rear seating surface part so as to be swivelable about a horizontal transverse axis, and which is held in its position relative to the rear seating surface part by a supporting kinematics;
 wherein the longitudinal axis runs between a central point and a front, upper region of the support kinematics;   wherein the restoring device uses an elastic deformation of the support kinematics as an energy accumulator and is thus a seating surface accumulator kinematics, and a targeted deformation of the seating surface accumulator kinematics is achieved in that:
 a control arm provided on one side of the seating surface and firmly connected thereto is swivelably connected at an other end about a horizontal bearing axis extending perpendicular to the plane of symmetry and provided on a lower edge of a substantially vertically-arranged squeeze plate; 
 the squeeze plate is swivelably connected at its upper edge about a support axis running parallel to a bearing axis to a front edge of a support plate, a rear edge of which is hinged to the base about an axis running parallel thereto; 
 a pyramid is provided including three rods with a base-fixed base plane and a tip through which the support axis runs; 
 two arms extending laterally outwards extend from a tip of the pyramid in a swivelable manner, the two arms having free ends which are swivelably mounted on the bearing axis; and 
   whereby, when the piece of seating furniture is deflected from the rest position, the control arm, the squeeze plate, and the support plate are elastically deformed in a buckling manner and thus act as energy accumulator and provide the restoring torque.