Throat plate for double chainstitch sewing machines

Claim 2

A double chainstitch sewing machine having a vertical reciprocating needle for carrying an upper thread, a threadcarrying chainstitch looper, a thread spreader cooperating with said chainstitch looper and said needle for allowing the forming of chainstitches in every feed direction of a workpiece, a horizontal bedplate having an opening formed therein and a throat plate rotatably received in said opening, said throat plate being rotatable about the axis of said needle and having a through bore therein forming a stitch hole, and oppositely disposed slotshaped grooves formed in a wall of said bore for receiving said sewing threads during the formation of a seam and for the alignment of said grooves in feed direction of a workpiece when a seam is formed.

Claim 3

In a double chainstitch sewing machine according to claim 1, wherein said throat plate is further provided with a cylindrical portion and a flange, ball bearings received within said opening and supporting said cylindrical portion and said flange of said throat plate.

Claim 4

In a double chainstitch sewing machine according to claim 1, further having a pattern with a contour for guiding a workpiece beneath said needle, corresponding to the contour of said pattern, and wherein said throat plate is formed with a flattening on the side portion thereof, said flattening extending parallel with said slot-shaped grooves for engaging with said contour of said pattern to align said grooves corresponding to said contour of said pattern.

Claim 5

In a double chainstitch sewing machine having a vertical reciprocating needle carrying an upper thread, a thread-carrying chainstitch looper, a thread spreader cooperating with said chainstitch looper and said needle for allowing the forming of chainstitches in every feed direction of a workpiece, a horizontal bedplate having an opening, formed therein a throat plate rotatably received in said opening, and a workpiece presser member enclosing said needle, said throat plate being rotatable about the axis of said needle and having a stitch hole and an elongated groove formed therein with said elongated groOve increasing in depth into said stitch hole, said elongated groove receiving said sewing threads during the formation of a seam and adapted to extend opposite to the feed direction of a workpiece when a seam is formed.

Claim 6

In a double chainstitch sewing machine having a vertical reciprocating needle carrying an upper thread, a thread-carrying chainstitch looper, a thread spreader cooperating with said chainstitch looper and said needle for allowing the forming of chainstitches in every feed direction of a workpiece, a horizontal bedplate having an opening, formed therein a throat plate rotatably received in said opening, and a workpiece presser member enclosing said needle, said throat plate being rotatable about the axis of said needle and having a stitch hole and an elongated groove formed therein with said elongated groOve increasing in depth into said stitch hole, said elongated groove receiving said sewing threads during the formation of a seam and adapted to extend opposite to the feed direction of a workpiece when a seam is formed.

Claim 7

In a double chainstitch sewing machine according to claim 4, further having a pattern with a contour for guiding a workpiece beneath said needle corresponding to the contour of said pattern, and wherein said throat plate is provided with beveled side portions in a zone about said stitch hole and the two sides beveled side portions running parallel with said elongated groove, said beveled side portions being widened from the top downwards, said pattern having a chamfered edge at said contour for cooperating with said beveled portions of said throat plate, a spring secured to said throat plate and said bedplate for biasing said throat plate to said chamfered edge of said pattern and aligning said elongated groove in parallel with said chamfered edge of said pattern.

Claim 8

In a sewing device with guided control of a sewing cycle, in combination, a support means, a turntable pivoted on said support means a guided pattern mounted below said turntable, workpiece clamping means mounted above said turntable and comprising a lower pattern having a contour corresponding to the seam to be sewn, and an upper clamp plate for clamping a workpiece upon said lower pattern, a swingable link arm on said support means, a supporting arm pivoted on said link arm, a driven magnetic roller secured to said supporting arm and engaged with the peripheral edge of said guide pattern, a double chainstitch sewing machine carried by said supporting arm and having a vertical reciprocating needle carrying an upper thread, a thread-carrying chainstitch looper, a thread spreader cooperating with said chainstitch looper and said needle for allowing the forming of chainstitches in every feed direction of said workpiece, a horizontal bedplate having an opening formed therein a throat plate rotatably received in said opening, and a workpiece presser member enclosing said needle, said throat plate being rotatable about the axis of said needle and having a stitch hole and an elongated groove formed therein, said elongated groove increasing in depth toward said stitch hole, said elongated groove receiving said sewing threads during the formation of a seam and adapted to extend opposite to the feed direction of a workpiece, and said throat plate being further provided with beveled side portions in a zone about said stitch hole and the two sides running parallel with said elongated groove, said beveled portions increasing in cross section with downwardly, said lower pattern having a chamfered edge of said contour for cooperation with said beveled portions of said throat plate, and a spring secured to said throat plate and said bedplate for biasing said throat plate to said chamfered edge of said lower pattern and aligning said elongated groove in parallel with said chamfered edge of said pattern.

Claim 9

In a sewing device with guided control of a sewing cycle, in combination, a support means, a turntable pivoted on said support means a guided pattern mounted below said turntable, workpiece clamping means mounted above said turntable and comprising a lower pattern having a contour corresponding to the seam to be sewn, and an upper clamp plate for clamping a workpiece upon said lower pattern, a swingable link arm on said support means, a supporting arm pivoted on said link arm, a driven magnetic roller secured to said supporting arm and engaged with the peripheral edge of said guide pattern, a double chainstitch sewing machine carried by said supporting arm and having a vertical reciprocating needle carrying an upper thread, a thread-carrying chainstitch looper, a thread spreader cooperating with said chainstitch looper and said needle for allowing the forming of chainstitches in every feed direction of said workpiece, a horizontal bedplate having an opening formed therein a throat plate rotatably received in said opening, and a workpiece presser member enclosing said needle, said throat plate being rotatable about the axis of said needle and having a stitch hole and an elongated groove formed therein, said elongated groove increasing in depth toward said stitch hole, said elongated groove receiving said sewing threads during the formation of a seam and adapted to extend opposite to the feed direction of a workpiece, and said throat plate being further provided with beveled side portions in a zone about said stitch hole and the two sides running parallel with said elongated groove, said beveled portions increasing in cross section with downwardly, said lower pattern having a chamfered edge of said contour for cooperation with said beveled portions of said throat plate, and a spring secured to said throat plate and said bedplate for biasing said throat plate to said chamfered edge of said lower pattern and aligning said elongated groove in parallel with said chamfered edge of said pattern.