A spring mechanism for a chair or a stool includes a base mount connected to a base and a seat mount connected to a seat. Two swing arms are arranged above one another. The two swing arms include a lower swing arm and an upper swing arm. Each of the two swing arms is pivotally connected to the seat mount and pivotally connected to the base mount. A spring is provided and arranged to generate an upwardly directed force onto the seat.

Suspension device for a vehicle seat, comprising an upper suspension portion and a lower suspension portion, which are interconnected by a first swivel connector and a second swivel connector, wherein the suspension device comprises a first adjustable toothed wheel element arranged on the upper suspension portion, a second toothed wheel element connected to the first swivel connector for adjusting a position of a first spring unit, by means of which a spring force and a spring rate of the suspension device can be changed, and a third toothed wheel element which is at least operatively connected to the first and the second toothed wheel element and is connected to the first swivel connector.

Suspension device for a vehicle seat, comprising an upper suspension portion and a lower suspension portion, which are interconnected by a first swivel connector and a second swivel connector, and the first and the second swivel connector are pivoted in each case about a swivel pin in the case of an oscillating movement of the upper suspension portion relative to the lower suspension portion, wherein a first toothed wheel element which is rotatable about a first axis of rotation is arranged on the first swivel connector for adjusting a position of a first spring unit, by means of which a spring force and a spring rate of the suspension device can be changed, the first toothed wheel element being in operative contact with a second toothed wheel element which is rotatable about a second axis of rotation.

Suspension device for a vehicle seat, comprising an upper suspension portion and a lower suspension portion, said suspension portions being connected to one another by a first swivel connector and a second swivel connector, said first swivel connector being arranged on the lower suspension portion in such a way that it can swivel about a first swivel pin, and said second swivel connector being arranged on the lower suspension portion in such a way that it can swivel about a second swivel pin, a first tension spring and a second tension spring being respectively connected to the first swivel connector by means of a first end region and to the upper suspension portion or the lower suspension portion by means of a second end region, wherein the first end region of the first tension spring is attached to the first swivel connector at a first distance therefrom, and the first end region of the second tension spring is attached to the first swivel connector at a second distance therefrom, the length of the first distance being variable.

A seat suspension includes a base including a base hook and a seat platform provided with a seat. A first link couples a first rotational axis of the base and a third rotational axis of the seat platform and is configured to be rotatable about the first rotational axis and the third rotational axis. A second link couples a second rotational axis of the base and a fourth rotational axis of the seat platform and is configured to be rotatable about the second rotational axis and the fourth rotational axis. A link hook is provided on the second link. An elastic member is latched to the base hook and the link hook and is configured to pull the link hook toward the base hook. A first angle between a contracting direction of the elastic member and a rotation direction of the link hook increases as the elastic member expands.

A body weight adjustment mechanism for automatic adjustment to a balanced point is provided to improve vibration absorption characteristics and impact absorption characteristics. A torsion angle of a lower frame-side torsion bar when an upper frame is at a balanced point is found in advance, a torsion angle of the lower frame-side torsion bar in a state in which a person is seated is detected, the detected torsion angle is compared with the aforesaid balanced point torsion angle, a control signal is sent to an elastic force adjusting unit, and torsion angles of upper frame-side torsion bars are adjusted so that the torsion angle of the lower frame-side torsion bar becomes equal to the balanced point torsion angle. The upper frame can be set to an appropriate position in an initial state and a static state in which a person is seated and vibration and impact absorption characteristics are improved.

There are improved a vibration absorption characteristic and an impact absorption characteristic. A seat suspension mechanism set so that links of a first link mechanism on a base frame side and links of a second link mechanism on a seat support frame side, between which an intermediate frame is put, differ in operating angles, that is, so that the links of the second link mechanism operate in the range of an angle closer to a vertical to a front-rear direction of a vehicle body. This allows front-rear movement of the seat support frame through the second link mechanism to mainly respond to input vibrations of front-rear movement to thereby improve a vibration absorption characteristic and an impact absorption characteristic in the front-rear direction.

A body weight adjustment mechanism for automatic adjustment to a balanced point is provided to improve vibration absorption characteristics and impact absorption characteristics. A torsion angle of a lower frame-side torsion bar when an upper frame is at a balanced point is found in advance, a torsion angle of the lower frame-side torsion bar in a state in which a person is seated is detected, the detected torsion angle is compared with the aforesaid balanced point torsion angle, a control signal is sent to an elastic force adjusting unit, and torsion angles of upper frame-side torsion bars are adjusted so that the torsion angle of the lower frame-side torsion bar becomes equal to the balanced point torsion angle. The upper frame can be set to an appropriate position in an initial state and a static state in which a person is seated and vibration and impact absorption characteristics are improved.

A seat for a vehicle including support links enabling a rotating motion and a sliding motion between a seat frame and seat rails, the support links being mounted so that the seat may be rotated in the forward and rearward directions as in a seesaw motion about a shaft of a vehicle in a width direction of the vehicle, so as to easily implement a facing mode posture, in which passengers sit facing each other, a relaxed comfort posture, etc.

A connection bar mounting structure includes: link members, each including a first hole part in a middle part; vehicle members, each configured to rotatably support each link member at a first fixation part of each link member; side frames, each configured to rotatably support each link member at a second fixation part of each link member opposite to the first fixation part across the first hole part; and a connection bar, each end thereof fixed to the first hole part of each link member. Each link member has a first bending rigidity reduced section between the middle part and the first fixation part and a second bending rigidity reduced section between the middle part and the second fixation part, the first and second bending rigidity reduced sections having bending rigidity smaller than those of the middle part, the first fixation part, and the second fixation part.