| 摘要 |
<p>A sash window restrictor 20, 120, has a housing 22, 122, which is to be let into a vertical frame member (10, fig.1) to limit movement of a sash window. A sash obstructing tab 24, 124, is mounted in the housing and obstructing tab can be retracted into the housing so as not to block a sash or extended from the housing to stop a sash. A mechanism acts between the tab and the housing and allows the tab to be pressed into the housing and held in the housing for a period of time before the tab is released to allow the tab to extend. The sash abutting tab may be mounted for pivotal or sliding movement and may be spring biased into the extended blocking position or moved due to gravity. The obstructing tab may be positively held in the retracted position by a latch mechanism such as a push-push mechanism whereby a first push withdraws the tab and a second push extends the tab; the second push either being manually pressed by an operator or actuated automatically by the passing of a window to the closed position to automatically release and extend the tab blocking subsequent movement toward the open position. A timing mechanism may be used to provide a predetermined delay prior to releasing the tab from the retracted position. Instead of a latching mechanism the tab may comprise a damping means to slow the movement of the tab and provide a delay between movement from the retracted position to the extended position. A second lock may be provided to lock the tab in the extended position. The pivotal embodiment may have multiple coil spring biased sprocket wheels and include a clutch mechanism.</p> |
