| 摘要 |
A lock mechanism for use with a screen having a generally square or rectangular configuration and elongated hooks or flanges along two opposed side edges thereof, and rails which extend along and engage the hooks. The lock mechanism comprises at least one arm and a crank. The arm has an outer end coupled to a rail and an inner end pivotably connected to the crank. The crank is rotatable about an axis and it is pivotably connected to the arm on an axis which is spaced from the axis of rotation. Rotation of the crank in one direction causes the arm to be extended outwardly and stretch the screen; rotation of the crank in the other direction retracts the arm and relaxes the screen. A lock is provided between the arm and the crank to hold the arm extended, and a spring is preferably provided between the arm and the associated rail. Preferably a second arm, connected similarly to the first mentioned arm, connects the crank with the other rail.
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