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