| 摘要 |
Sheet feed apparatus for intermittently advancing a sheet, such as a thermoplastic sheet including a frame, sheet engaging mechanism reciprocally mounted on the frame for intermittently advancing the sheet, mechanism for reciprocally moving the sheet engaging mechanism in a to-and-fro path of travel including a stationary shaft and a rotatable shaft concentric with the stationary shaft, a primary crank arm fixed to the moveable shaft for rotation therewith, a secondary crank arm rotatably mounted on the primary crank arm for rotation relative thereto, and mechanism coupling the primary crank arm and the secondary crank arm for rotatably driving the secondary crank arm in a direction opposite the direction of rotation of the primary crank arm.
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