| 摘要 |
<p>A screen assembly includes first and second frame members, a spring biased roller rotatably mounted in one of the frame members. A screen is fixed at one end to the roller and is fixed at a second end to the other of the frame members. An extendable linkage assembly connects the frame members and includes a first arm hingedly connected to the first frame member, at a point offset from a center thereof, a second arm hingedly connected to the first arm and to the second frame member, proximal a center thereof, a third arm hingedly connected to the first frame member, at a point on an opposing side of center as the first arm and a fourth arm hingedly connected to the third arm and to the second frame member, proximal the center. The linkage assembly also includes a first biasing member connected along the second arm and to the second frame member, on one side of the center and a second biasing member connected along the fourth arm and to the second frame member, at a point on an opposing side of the center. The first and second frame members are positionable between a closed position and an open position.</p> |
