Abstract: In an automated bobbin-exchanger device (3), a guide groove (6) which is provided on a vertical transfer base (5) has a horizontal portion (6a), a vertical portion (6c) and an arcuate portion (6b). A bobbin chuck (18) reciprocally moves pivotably along the guide groove (6) to make a travel distance minimum, thus enabling users to quickly exchange the bobbin case (12). By placing a bobbin holder (13a), a chuck-drive lever (14) and a chuck-drive air-cylinder (26) circumferentially, it is possible to make a whole structure compact and space-saving. The bobbin-exchanger device (3) requires only two bobbin cases (12) available to make their check and maintenance easy.

Abstract: In an automated bobbin-exchanger device (3), a guide groove (6) which is provided on a vertical transfer base (5) has a horizontal portion (6a), a vertical portion (6c) and an arcuate portion (6b). A bobbin chuck (18) reciprocally moves pivotably along the guide groove (6) to make a travel distance minimum, thus enabling users to quickly exchange the bobbin case (12). By placing a bobbin holder (13a), a chuck-drive lever (14) and a chuck-drive air-cylinder (26) circumferentially, it is possible to make a whole structure compact and space-saving. The bobbin-exchanger device (3) requires only two bobbin cases (12) available to make their check and maintenance easy.

Abstract: In an automated skip checker device for sewing machine 1, a detector device 8 detects a slack portion 3a of a predetermined length D. The slack portion 3a definitely corresponds to a skip of a stitch or a disconnection of a sewing thread so as to unerringly carry out the detection with a high accuracy. The detector device 8 of the skip checker device has an air stream provider 19 which transfers a tension to an upper thread 3 as a pneumatic pressure to energize an optoelectronic switch 23 so as to make the detector device 8 structurally compact and cost-saving.

Abstract: In a remote control bobbin case exchanger device (1), a rotary bobbin (K) is to be placed in a position that is not easily accessed, and an exchangeable position (&agr;) is provided in a position that is readily accessed in a bobbin case providing member (3). A chuck driving member (6) moves a chuck member (5) toward the rotary bobbin (K) to clutch a bobbin case (2) along a line connecting the rotary bobbin (K) to the exchangeable position (&agr;).

Abstract: In an under thread detection device for a sewing machine, a probe arm is located outside a rotary bobbin case, and is adapted to be accessible to a bobbin through a space provided at the rotary bobbin case when the rotary bobbin case ceases its rotary movement. An urging member provides an urging force in such a direction as to urge the probe arm toward a stem of the bobbin. A wire transmits the urging force of the urging member to the probe arm. A stroke detection device measures a stroke displacement of the wire. A detection control device calculates a residual amount of an under thread wound on the bobbin on the basis the stroke displacement measured by the stroke detection device. A display device exhibits the residual amount of the under thread wound on the bobbin on the basis of the calculation performed by the detection control device.