Patent ID: 8312824

Claim:
A thread cutter for a sewing machine, which is provided on an underside of a needle plate having a needle hole and cuts a needle thread and a bobbin thread both located between a workpiece cloth and a rotary hook including an outer rotating hook and an inner bobbin case, the thread cutter comprising: a first thread seizing assembly which is supported so as to be reciprocally movable and has a distal end provided with a first thread seizing portion, the first thread seizing assembly seizing a needle thread having passed the bobbin case and a bobbin thread by the first thread seizing portion, the bobbin case housing a bobbin on which a bobbin thread is wound, the bobbin thread extending from the bobbin to the needle hole of the needle plate; a cutting blade located nearer to the needle hole side than a movement locus of the first thread seizing assembly; a second thread seizing assembly which seizes the needle and bobbin threads both having been seized by the first thread seizing assembly during a backward movement of reciprocation of the first thread seizing assembly, cutting the needle and bobbin threads in cooperation with the cutting blade; a thread cutting frame which supports the first thread seizing assembly and which is formed with a single elongated groove which supports the first thread seizing assembly so that the first thread seizing assembly is reciprocally movable, the elongated groove including a linear proximal end groove, an oblique portion, and a main groove and being shaped such that the proximal end groove is translated slightly forward through the oblique portion; and a drive unit which drives the first and second thread seizing assemblies, wherein when moved backward in the reciprocation, the first thread seizing assembly is swung so that the first thread seizing portion comes close to the second thread seizing assembly.