Abstract: A sewing machine includes a thread holding device disposed downstream of a thread take-up lever and upstream of a needle bar in terms of a threading path of a needle thread, and including a fixed first disc and a movable second disc movable by an electromechanical unit between holding and releasing positions to be closer to and remote from the first disc, respectively. The first and second discs respectively have first and second holding surfaces cooperatively defining a thread holding clearance to permit passage of the needle thread therethrough. The needle thread can be clamped in the thread holding clearance so as to prevent the needle thread being pulled out of the needle during a thread cutting procedure. A required amount of the needle thread remaining on the needle can be secured.

Abstract: A clutch device used to couple/decouple a reciprocating force of a drive member to/from a needle bar in a sewing machine includes an actuating lever actuated by an electromechanical unit to be pivotable between an idle position to disengage from an actuated end of a clutch lever so as to leave a grasp end of the clutch lever in a coupled state, where the grasp end is engaged with a coupled portion disposed on a drive member, thereby transmit the reciprocating force to the needle bar, and an actuating position to be in pressing engagement with the actuated end so as to displace the grasp end to a decoupled state, where the grasp end is disengaged from the coupled portion.

Abstract: A feed dog device for a sewing machine includes a feed dog mount mounted under a needle plate and having a feed dog mounted thereon to permit the feed dog to extend through slots in the needle plate. The feed dog mount is coupled with a lever through a force transmitting unit to couple an increased torque generated by a pivotal movement of the lever to the feed dog mount so as to enable a weight end of the lever to drive the feed dog mount to move reciprocatingly in a transverse direction perpendicular to a normal feeding direction of a fabric. The lever is actuated by a cam follower with a torque generated as a result of transmission through a rotary cam member which is rotated with an output shaft of the drive member. Since the feed dog can be reciprocatingly moved in the transverse direction, the sewing machine can perform a variety of sewing operations.

Abstract: A sewing machine includes a thread holding device disposed downstream of a thread take-up lever and upstream of a needle bar in terms of a threading path of a needle thread, and including a fixed first disc and a movable second disc movable by an electromechanical unit between holding and releasing positions to be closer to and remote from the first disc, respectively. The first and second discs respectively have first and second holding surfaces cooperatively defining a thread holding clearance to permit passage of the needle thread therethrough. The needle thread can be clamped in the thread holding clearance so as to prevent the needle thread being pulled out of the needle during a thread cutting procedure. A required amount of the needle thread remaining on the needle can be secured.

Abstract: A thread cutting device is adapted to be mounted under a bed of a sewing machine, and includes a mount having a marginal region which confronts a thread fetching zone, and a guide slot which is elongated parallel to a stroke path, a fixed knife disposed on the marginal region and having a blade aligned with the stroke path, a movable knife having a shank body which extends along the stroke path to terminate at actuated and hook ends, a drive unit disposed under the mount and having a rotatable output shaft to deliver a rotational force, and a rotation/translation conversion mechanism disposed to convert the rotational force into a translational force that is transmitted through the guide slot to actuate a translation of the actuated end of the shank body to thereby move the shank body between fetching and thread cutting positions.

Abstract: A clutch device used to couple/decouple a reciprocating force of a drive member to/from a needle bar in a sewing machine includes an actuating lever actuated by an electromechanical unit to be pivotable between an idle position to disengage from an actuated end of a clutch lever so as to leave a grasp end of the clutch lever in a coupled state, where the grasp end is engaged with a coupled portion disposed on a drive member, thereby transmit the reciprocating force to the needle bar, and an actuating position to be in pressing engagement with the actuated end so as to displace the grasp end to a decoupled state, where the grasp end is disengaged from the coupled portion.

Abstract: A thread cutting device is adapted to be mounted under a bed of a sewing machine, and includes a mount having a marginal region which confronts a thread fetching zone, and a guide slot which is elongated parallel to a stroke path, a fixed knife disposed on the marginal region and having a blade aligned with the stroke path, a movable knife having a shank body which extends along the stroke path to terminate at actuated and hook ends, a drive unit disposed under the mount and having a rotatable output shaft to deliver a rotational force, and a rotation/translation conversion mechanism disposed to convert the rotational force into a translational force that is transmitted through the guide slot to actuate a translation of the actuated end of the shank body to thereby move the shank body between fetching and thread cutting positions.

Abstract: A feed dog device for a sewing machine includes a feed dog mount mounted under a needle plate and having a feed dog mounted thereon to permit the feed dog to extend through slots in the needle plate. The feed dog mount is coupled with a lever through a force transmitting unit to couple an increased torque generated by a pivotal movement of the lever to the feed dog mount so as to enable a weight end of the lever to drive the feed dog mount to move reciprocatingly in a transverse direction perpendicular to a normal feeding direction of a fabric. The lever is actuated by a cam follower with a torque generated as a result of transmission through a rotary cam member which is rotated with an output shaft of the drive member. Since the feed dog can be reciprocatingly moved in the transverse direction, the sewing machine can perform a variety of sewing operations.