Sewing machine stitching mechanism

Claim 1

In a sewing machine of the type having a thread supply, a reciprocating needle with an opening through the pointed end of said needle for thread, and a work surface plate which includes a needle passage Therethrough for receiving said reciprocating needle and thread, the improvement comprising, in combination: thread-looping means positioned beneath said work surface plate adapted to engage a loop formed by said thread when said needle is extended through said plate and hold said loop in position to form a chain stitch as said needle reciprocates through said plate and material on said work surface plate, said looping means including first and second parallel adjacent arms adapted to move toward and away from the loop formed by thread through said opening in said needle and thread-retaining means cooperating with said arms, said parallel arms also adapted to spread and come together in a direction substantially perpendicular to the direction of needle travel and said thread-retaining means being adapted to provide retention of a loop of thread between said retaining means and said arms.

Claim 4

A method for sewing a chain stitch in material using a sewing machine of the type having a thread supply, a reciprocating needle with an opening through the pointed end of said needle for thread, and work surface plate which includes a needle passage therethrough for receiving said reciprocating needle and thread, which comprises the steps of moving said needle and thread passing through said needle passage through said material and said opening in said work surface plate to a first extreme position; retracting said needle from said first extreme position and simultaneously positioning a pair of arms through a loop formed by said thread and said needle; retaining said loop between retaining means and said pair of arms; further retracting said needle through said work surface plate and said material to a second extreme position and simultaneously maintaining said pair of arms in substantially the position of intersection with said loop; advancing said material on said work surface plate; spreading said pair of arms to open said loop; moving said needle again from second extreme position towards said first extreme position through said material and said work surface plate, said needle passing through said loop; retracting said arms from said position of intersection thereby causing said loop to be disengaged from said spread arms and said retaining means, said thread passing over said moving needle; and rejoining said spread arms.

Claim 5

A method for sewing a chain stitch in material using a sewing machine of the type having a thread supply, a reciprocating needle with an opening through the pointed end of said needle for thread, and work surface plate which includes a needle passage therethrough for receiving said reciprocating needle and thread, which comprises the steps of moving said needle and thread passing through said needle passage through said material and said opening in said work surface plate to a first extreme position; retracting said needle from said first extreme position and simultaneously positioning a pair of arms through a loop formed by said thread and said needle; retaining said loop between retaining means and said pair of arms; further retracting said needle through said work surface plate and said material to a second extreme position and simultaneously maintaining said pair of arms in substantially the position of intersection with said loop; advancing said material on said work surface plate; spreading said pair of arms to open said loop; moving said needle again from second extreme position towards said first extreme position through said material and said work surface plate, said needle passing through said loop; retracting said arms from said position of intersection thereby causing said loop to be disengaged from said spread arms and said retaining means, said thread passing over said moving needle; and rejoining said spread arms.