| 摘要 |
The adjustable back support device (20) has a generally U-shaped base (22) and a pivoting back portion (24) which can be adjusted to a forward/upright position, a backward/reclining position and any angle of inclination thereinbetween. An adjustment and retaining mechanism connects the base and the back portion to permit adjustment to and/or retention in a desired position and includes an inflatable bellows (28), a forward biasing spring (34, 35), an airflow passageway (33) and an airflow activating valve assembly (56). When the valve assembly activates the airflow, the forward biasing spring forces the back portion (24) to a forward position in the absence of any counter force. When the valve assembly is activated simultaneously with a user-applied backward force on the back portion, the back portion pivots to a backward position. |
