Importance

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Abstract

A feed mechanism for a buttonhole sewing machine has a movable plate with a clamped piece of cloth. A rack is formed on a rearward extension of the plate. A pinion engages the rack, and a large gear is fixed to the pinion. An upper driving gear drives the large gear and is fixed to a vertical stub shaft which extends through the base of the sewing machine. A lower driving gear is mounted on the lower end of the vertical stub shaft beneath the work-supporting surface. A longitudinally shiftable horizontal shaft is mounted beneath the vertical stub shaft. A left bevel gear and a right bevel gear are keyed to the shiftable shaft. The shaft may be shifted so that either one or the other bevel gear engages the gear on the vertical stub shaft, or to an intermediate position in which the bevel gears are disengaged. The horizontal shaft is driven by a ratchet mechanism. In operation, the horizontal shaft is shifted so that the right bevel gear drives the lower driving gear and bight stitches are formed along a first side of a buttonhole. The bevel gears are disengaged and tack stitches are made at the second end of the buttonhole. The left bevel gear engages the lower driving gear, moving the plate and feeding the cloth back while bight stitches are made along the second side of the buttonhole. The bevel gears are disengaged for forming tack stitches at the first end of the buttonhole.

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First Claim