A buttonhole sewing guiding device of a sewing machine includes a buttonhole presser foot unit disposed on a presser foot holder of the sewing machine, and a sensing unit disposed on the buttonhole presser foot unit. A presser frame of the foot unit is movable relative to a sliding member between first and second sewing positions set in accordance with an operating distance that corresponds to a size of a button to allow first and second triggering members to initiate a sensing module for controlling operation of a sewing needle.

A buttonhole sewing guiding device of a sewing machine includes a buttonhole presser foot unit disposed on a presser foot holder of the sewing machine, and a sensing unit disposed on the buttonhole presser foot unit. A presser frame of the foot unit is movable relative to a sliding member between first and second sewing positions set in accordance with an operating distance that corresponds to a size of a button to allow first and second triggering members to initiate a sensing module for controlling operation of a sewing needle.

A sewing machine can detect a sewing target feeding length, and includes: a presser rod, a presser main body detachably mounted on the presser rod, a movable presser portion mounted on the presser main body such that it can be pressed in contact with a sewing target in the sewing operation, and such that it is movable with the sewing target in feeding and reverse feeding directions; a movement transmission portion configured having one end that can be coupled with the movable presser portion, and having an other end that receives a position change of the one end; a slide volume that detects the position change of the other end, and a calculation unit that calculates the position change of the movable presser portion based on the detection result obtained by the slide volume.

A sewing machine can detect a sewing target feeding length, and includes: a presser rod, a presser main body detachably mounted on the presser rod, a movable presser portion mounted on the presser main body such that it can be pressed in contact with a sewing target in the sewing operation, and such that it is movable with the sewing target in feeding and reverse feeding directions; a movement transmission portion configured having one end that can be coupled with the movable presser portion, and having an other end that receives a position change of the one end; a slide volume that detects the position change of the other end, and a calculation unit that calculates the position change of the movable presser portion based on the detection result obtained by the slide volume.

A sewing machine can detect a sewing target feeding length, and includes: a presser rod, a presser main body detachably mounted on the presser rod, a movable presser portion mounted on the presser main body such that it can be pressed in contact with a sewing target in the sewing operation, and such that it is movable with the sewing target in feeding and reverse feeding directions; a movement transmission portion configured having one end that can be coupled with the movable presser portion, and having an other end that receives a position change of the one end; a slide volume that detects the position change of the other end, and a calculation unit that calculates the position change of the movable presser portion based on the detection result obtained by the slide volume.

A precise positioning mechanism for automatic hat-making production line equipment includes a rack, an installation seat, a jacking device, a positioning column, a material pickup and discharging platform, a support column, a guide rod, and an infrared ranging sensor. The material pickup and discharging platform is located at a top of one side of the rack. The installation seat is arranged on both sides of a bottom of the material pickup and discharging platform separately through bolts. The jacking device is arranged at a bottom of the installation seat of the material pickup and discharging platform through bolts. The positioning column corresponding to a position of the jacking device is inserted into both sides of a top of the material pickup and discharging platform separately. An output end of the jacking device and a bottom of the positioning column are connected through bolts.

A precise positioning mechanism for automatic hat-making production line equipment includes a rack, an installation seat, a jacking device, a positioning column, a material pickup and discharging platform, a support column, a guide rod, and an infrared ranging sensor. The material pickup and discharging platform is located at a top of one side of the rack. The installation seat is arranged on both sides of a bottom of the material pickup and discharging platform separately through bolts. The jacking device is arranged at a bottom of the installation seat of the material pickup and discharging platform through bolts. The positioning column corresponding to a position of the jacking device is inserted into both sides of a top of the material pickup and discharging platform separately. An output end of the jacking device and a bottom of the positioning column are connected through bolts.

The disclosure improves the quality of seams in sewing using a sewing machine, and includes: a holder holding fabric; a driver being detachable from a bed of a sewing machine and driving the holder along an upper surface of the bed; a position detector detecting a position of a sewing needle of the sewing machine in an up-down direction; and a controller controlling driving of the holder, which is performed by the driver, based on a detection result of the position detector.

A sewing machine external unit includes: a holder holding fabric; a driver being detachable from a bed of a sewing machine and driving the holder along an upper surface of the bed; a pressing member moving in an up-down direction according to movement of a sewing needle in the up-down direction, pressing the fabric while the sewing needle is stuck in the fabric, and rising together with the sewing needle in response to the sewing needle coming out of the fabric and rising; a position detector detecting a position of the pressing member in the up-down direction; a signal output part outputting a signal to the sewing machine; and a controller outputting a needle drive signal for driving the sewing needle from the signal output part to the sewing machine, and controlling driving of the holder and/or the sewing needle based on a detection result of the position detector.