| 摘要 |
<p>An override device is proposed to permit the manual operation of a closure which is normally driven by an electric motor. The override device comprises a manual closure driving mechanism, such as a chain engaged around a pulley, which when operated first produces the translation of a first gear along its rotation axis until this first gear meshes with a second gear connected to the output shaft of the motor which normally drives the closure. During the translation of the first gear, a switch is tripped to safely interrupt power to the motor and a mechanism is operated to disengage the motor from the output shaft. Thereafter, further operation of the chain, and therefore further rotation of the pulley, is adapted to cause the first gear to rotate instead of translating, whereby the second gear is driven into rotation by the first gear thereby causing the rotation of the output shaft and the manual operation of the closure. More particularly, the first gear is prevented from rotating with a cam mechanism associated with the pulley causing the translation of the first gear and, once the first and second gears become so engaged, the first gear can rotate with the pulley.</p> |
