| 摘要 |
An apparatus for forming a double tuck on a lateral edge of a length of material web comprises a U-shape folding bar for supporting the material at a spaced location from the edge of the material and which includes a lower leg and an upper leg interconnected by a web or yoke. A stave is mounted for upward and downward motion adjacent the folding bar in a plane spaced from the yoke portion by the thickness of the web and being movable downwardly for folding the lateral edge about the yoke portion. A fold slide is mounted for transverse movement in a plane adjacent to and spaced from the lower leg by the thickness of the web and it is movable toward the lower leg for folding the lateral edge against the lower surface of the lower leg. A folding plate is mounted for upward and downward movement in a plane adjacent to and spaced from the lower leg by the thickness of the web in order to tuck over the edge of the material around the edge of the leg and it is movable transversely parallel to the plane of the lower leg and in a plane spaced above the lower leg by the thickness of the web in order to form the bottom tuck of the material. A first conveyor belt is arranged to move along the fold slide and is engageable against the bottom of the material and a second conveyor is mounted above the folding bar and is engageable with the top of the material and the first and second conveyors operate together to advance the material into association with the sewing needle. In addition, there is at least one auxiliary feed means in the form of a movable feed plate which engages the material at the bottom face thereof directly adjacent the tucked over portion and to feed it at a different linear speed than the remaining portion of the web in order to maintain the alignment of the folded edge with the remaining length of the material web.
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