| 摘要 |
Disclosed is an improved top feed arrangement for cooperation with a conventional lower feed dog of a sewing machine, the lower feed dog cyclically engaging and disengaging the lower surface of material to be sewn in order to move that lower surface along a predetermined path through and past the sewing machine. The top feed arrangement comprises an upper feed dog carried by an arm that is pivotally linked to the drive means causing the cyclical movement of the lower feed dog. The arm is connected to those drive means at one end in a pivotal connection and the upper feed dog is carried at the other end of the arm. Biasing means bear against the arm at a location intermediate the upper feed dog and the pivotal connection to the drive means. A lifter means, responsive to the drive system that actuates the sewing machine needle, periodically moves the upper feed dog in a direction away from the lower feed dog against the force of the biasing means. Preferably, the arm which carries the upper feed dog is guided for movement in a vertical plane by a first bearing surface of the arm engaging a vertical confining surface of the sewing machine frame and a second bearing surface engaging a confining surface of the biasing means.
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