| 摘要 |
A rain gutter includes a back wall, bottom member, and front wall, forming an elongated channel. The front wall is pivotally connected along the bottom member for forward movement between an upstanding position and a downward open position. An upright scavenger blade mounted in and along the channel is movable between a retracted position and a forward position to push the front wall open and dump the gutter contents. The scavenger blade includes a flexible wiper along its bottom to slide across the channel bottom. The system is actuated by a piston which reciprocates the scavenger blade across the channel, between retracted and extended positions. The actuator system also includes a base plate parallel to the back wall, a channel span parallel to the base plate, and parallel hinge plates connecting the base plate and channel span, all together forming a four-bar linkage. An actuator arm is pivotally connected at one end to the base plate, and slidably connected at its other end to the channel span. The piston actuator is pivotally connected at one end to the base plate and at its other end to an intermediate point of the actuator arm. The scavenger blade is so mounted to the channel span as to allow to blade to retain its lengthwise position in the channel independent of movement of the channel span.
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