| 摘要 |
The chair comprises a base 1, optionally provided with castors 2, carrying pneumatic height adjustment means in the form of a pneumatic piston-and-cylinder arrangement (3). A U-shaped frame member 6 is mounted on one end of the piston 3a, which frame member supports the chair arms 7 at its extremities. The back portion 8 of the chair is hingedly connected to the posterior extremities of these chair arms and the lower region of the back is hingedly connected to the seat portion 10. The seat portion is capable of longitudinal movement due to its mounting on sliding guides 12, 13 mounted on the central portion of the U-shaped frame 6. Accordingly, any change in the angle inclination of the back portion is associated with a corresponding movement of the seat portion so that the centre of gravity of the chair remains substantially stationary. At least a part of the back portion 8 may be resilient. <IMAGE> |
