| 摘要 |
<p>The invention relates to an unique apparatus for displacing an extensible/contractible board (5) for a chair in case of an occurrence of emergency is disclosed. The apparatus includes a board support (4), an engagement piece (6), a turn guide plate (3), a stationary guide plate (1) and an opposing pair of base members (8.1, 8.2). The board (5) assumes a horizontal attitude during normal use. In case of an occurrence of emergency, an excessive magnitude of outer force in excess of the resilient force derived from Belleville springs (7) is imparted to the board (5) by an user's hand so that the engagement piece (6) is disengaged from the turn guide plate (3) via operative engagement of an eccentric projection (52) on the board shaft (51) with an engagement recess (61) on the engagement piece (6). This causes the board (5) to be displaced from the horizontal attitude to a vertical attitude, whereby a sufficiently wide space is provided in front of an user so as to enable him to quickly escape from his chair (10). When the board (5) is not in use, the board (5) is received in a hollow space defined by an opposing pair of sleeve plates below one elbow rest of the chair.</p> |
