Programmed color stitching mechanisms for sewing machines

Claim 2

In a sewing machine for concatenating threads into successive stitches in a work fabric, a thread tensioning device on said sewing machine for imposing resistance to passage of a sewing thread to the stitches being concatenated, a preselected patterning means driven by said sewing machine in a recurring period spanning a plurality of successive stitches, and mechanism operatively connected to said thread tensioning device and responsive to said patterning means for varying the resistance which the tensioning device imposes to passage of a sewing thread.

Claim 3

In a sewing machine as set forth in claim 1 in which said thread tensioning device includes a first force generating means, mechanism for applying force from said first forCe generating means for imposing resistance to passage of a sewing thread to the stitches being concatenated, and means for manually regulating said first force generating means, and in which said mechanism responsive to said patterning means includes a second force generating means, and mechanism for adding force from said second force generating means to the force applied from said first force generating means.

Claim 4

Mechanism for automatically regulating the color of a lockstitch seam produced by a lockstitch sewing machine having differently colored needle and bobbin threads as the seam appears on an exposed face of a stitched work fabric, said mechanism comprising: a primary needle thread tensioning means, manually influenced means for regulating said primary needle thread tensioning means to produce lockstitches in which only the needle thread appears on an exposed face of a stitched work fabric, an auxiliary needle thread tensioning means for applying additional tension to said needle thread for drawing differently colored bobbin thread into view on the exposed face of a stitched work fabric, and programmed control means driven by said sewing machine for selectively rendering said auxiliary needle thread tensioning means effective.

Claim 5

Mechanism for automatically regulating the color of a lockstitch seam produced by a lockstitch sewing machine having differently colored needle and bobbin threads as the seam appears on an exposed face of a stitched work fabric, said mechanism comprising: a primary needle thread tensioning means, manually influenced means for regulating said primary needle thread tensioning means to produce lockstitches in which only the needle thread appears on an exposed face of a stitched work fabric, an auxiliary needle thread tensioning means for applying additional tension to said needle thread for drawing differently colored bobbin thread into view on the exposed face of a stitched work fabric, and programmed control means driven by said sewing machine for selectively rendering said auxiliary needle thread tensioning means effective.

Claim 6

Color regulating mechanism as set forth in claim 3 in which said primary and auxiliary needle thread tensioning means are effective to apply frictional resistance to passage of the needle thread toward the stitched work fabric by way of a thread engaging head of a single thread tensioning device.

Claim 7

Color regulating mechanism as set forth in claim 4 in which said primary and auxiliary needle thread tensioning means each includes a spring, and means for transmitting a force from said springs to the thread engaging head of said thread tensioning device, and in which said programmed control means renders selectively effective the transmitting means for the spring force of the auxiliary thread tensioning means.

Claim 8

Color regulating mechanism as set forth in claim 3 in which said programmed control means comprises a pattern cam driven by said sewing machine, and a cam follower actuated linkage responsive to said pattern cam for rendering said auxiliary needle thread tensioning means effective.

Claim 9

Mechanism for automatically regulating the color of a lockstitch zigzag seam produced by a lockstitch zigzag sewing machine having differently colored needle and bobbin threads as the seam appears on an exposed face of a stitched work fabric, said mechanism comprising a primary needle thread tensioning means, manually influenced means for regulating said primary needle thread tensioning means to produce zigzag stitches in which only the needle thread appears on an exposed face of a stitched work fabric, an auxiliary needle thread tensioning means for applying additional tension to said needle thread for drawing differently colored bobbin thread into view on the exposed face of a stitched work fabric, and programmed control means driven by said sewing machine for selectively rendering said auxiliary needle thread tensioning means effective.

Claim 10

Mechanism for automatically regulating the color of a lockstitch zigzag seam produced by a lockstitch zigzag sewing machine having differently colored needle and bobbin threads as the seam appears on an exposed face of a stitched work fabric, said mechanism comprising a primary needle thread tensioning means, manually influenced means for regulating said primary needle thread tensioning means to produce zigzag stitches in which only the needle thread appears on an exposed face of a stitched work fabric, an auxiliary needle thread tensioning means for applying additional tension to said needle thread for drawing differently colored bobbin thread into view on the exposed face of a stitched work fabric, and programmed control means driven by said sewing machine for selectively rendering said auxiliary needle thread tensioning means effective.

Claim 11

Color regulating mechanism as set forth in claim 7 in which zig-zag pattern cam means driven by said sewing machine is provided for producing repetitive groups of zig-zag stitches, and in which said programmed control means is driven by said sewing machine in timed relation with said zig-zag pattern cam means for rendering said auxiliary needle thread tensioning means effective only on preselected ones of said repetitive groups of zig-zag stitches.