| 摘要 |
A stacker for flat flexible sheets, such as pillow cases, is provided to add sheets to the bottom of a stack without relative frictional movement between the articles being stacked or between the stacking mechanism and the stacked articles. The stacker comprises a stacking plate, clamp bars adjacent the leading edge of successive sheets, and a fold bar movable in a fixed path above and rearwardly of the stacking plate against the upper surface of successive sheets while gripped at their leading edges. Movement of the fold bar under the stack while the leading edge of the sheet is clamped at the front of the stack folds the sheet on itself while the fold bar moves beyond the clamping mechanism toward the rear of the stack and positions the surface of the sheet opposite that engaged by the fold bar against the lower surface of a previously stacked sheet without frictional movement between the two sheets or between the fold bar and the last stacked sheet. The action is much like unrolling a rug on a floor, there being no frictional movement between the rug and the floor. The clamp bars are released after the sheet is added to the stack and means are provided to elevate the stacking plate above the clamp mechanism to position the trailing edge of the last added sheet on top of the clamp mechanism.
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