With an overlock sewing machine set to an interlock state and the upper blade in an interlock position, upon turning the operating shaft toward one side around its axis, an interlock switching mechanism displaces the other end portion of a rod and sets an interlock release state. A pressing portion presses a first switching portion to swing a swing member toward the forward swing side, which displaces the upper blade to retraction position. With the state set to interlock release with the upper blade in retraction position, upon turning the operating shaft toward one side around its axis, the pressing portion presses a second switching portion to swing the swing member toward the reverse swing side, which displaces the upper blade to interlock position. The interlock mechanism displaces the other end portion of the rod to set the state to interlock.

With an overlock sewing machine set to an interlock state and the upper blade in an interlock position, upon turning the operating shaft toward one side around its axis, an interlock switching mechanism displaces the other end portion of a rod and sets an interlock release state. A pressing portion presses a first switching portion to swing a swing member toward the forward swing side, which displaces the upper blade to retraction position. With the state set to interlock release with the upper blade in retraction position, upon turning the operating shaft toward one side around its axis, the pressing portion presses a second switching portion to swing the swing member toward the reverse swing side, which displaces the upper blade to interlock position. The interlock mechanism displaces the other end portion of the rod to set the state to interlock.

An overlock sewing machine includes an operating shaft that is slidable between first and second positions, and configured such that interlock switching and position switching mechanisms are operated when it is turned. The interlock switching mechanism includes a rotor that is rotatable together with the operating shaft as a single unit, an interlock switching member, and a first engagement target portion formed in the rotor. In the interlock state, setting the operating shaft to the first position engages an engagement portion of the interlock switching member with the first engagement target portion, which restricts operating shaft rotation. Sliding the operating shaft to the second position releases the engagement state between the engagement and first engagement target portions, enabling rotation of the operating shaft.

An overlock sewing machine includes an operating shaft that is slidable between first and second positions, and configured such that interlock switching and position switching mechanisms are operated when it is turned. The interlock switching mechanism includes a rotor that is rotatable together with the operating shaft as a single unit, an interlock switching member, and a first engagement target portion formed in the rotor. In the interlock state, setting the operating shaft to the first position engages an engagement portion of the interlock switching member with the first engagement target portion, which restricts operating shaft rotation. Sliding the operating shaft to the second position releases the engagement state between the engagement and first engagement target portions, enabling rotation of the operating shaft.

With an overlock sewing machine set to an interlock state and the upper blade in an interlock position, upon turning the operating shaft toward one side around its axis, an interlock switching mechanism displaces the other end portion of a rod and sets an interlock release state. A pressing portion presses a first switching portion to swing a swing member toward the forward swing side, which displaces the upper blade to retraction position. With the state set to interlock release with the upper blade in retraction position, upon turning the operating shaft toward one side around its axis, the pressing portion presses a second switching portion to swing the swing member toward the reverse swing side, which displaces the upper blade to interlock position. The interlock mechanism displaces the other end portion of the rod to set the state to interlock.

With an overlock sewing machine set to an interlock state and the upper blade in an interlock position, upon turning the operating shaft toward one side around its axis, an interlock switching mechanism displaces the other end portion of a rod and sets an interlock release state. A pressing portion presses a first switching portion to swing a swing member toward the forward swing side, which displaces the upper blade to retraction position. With the state set to interlock release with the upper blade in retraction position, upon turning the operating shaft toward one side around its axis, the pressing portion presses a second switching portion to swing the swing member toward the reverse swing side, which displaces the upper blade to interlock position. The interlock mechanism displaces the other end portion of the rod to set the state to interlock.

An overlock sewing machine includes an operating shaft that is slidable between first and second positions, and configured such that interlock switching and position switching mechanisms are operated when it is turned. The interlock switching mechanism includes a rotor that is rotatable together with the operating shaft as a single unit, an interlock switching member, and a first engagement target portion formed in the rotor. In the interlock state, setting the operating shaft to the first position engages an engagement portion of the interlock switching member with the first engagement target portion, which restricts operating shaft rotation. Sliding the operating shaft to the second position releases the engagement state between the engagement and first engagement target portions, enabling rotation of the operating shaft.

An overlock sewing machine includes an operating shaft that is slidable between first and second positions, and configured such that interlock switching and position switching mechanisms are operated when it is turned. The interlock switching mechanism includes a rotor that is rotatable together with the operating shaft as a single unit, an interlock switching member, and a first engagement target portion formed in the rotor. In the interlock state, setting the operating shaft to the first position engages an engagement portion of the interlock switching member with the first engagement target portion, which restricts operating shaft rotation. Sliding the operating shaft to the second position releases the engagement state between the engagement and first engagement target portions, enabling rotation of the operating shaft.

A sewing machine including a detection portion that detects a movement amount of a workpiece, a sewing machine motor that serves as a driving source for vertical movement of a needle bar, and a control device that controls the sewing machine motor based on the detection result by the detection portion and performs control to maintain a constant stitch pitch. The control device lengthens a period for obtaining an output of the detection portion when the movement amount of the workpiece per unit time based on the detection result by the detection portion is decreased, and shortens the period for obtaining the output of the detection portion when the movement amount of the workpiece per unit time based on the detection result by the detection portion is increased.

A sewing machine including a detection portion that detects a movement amount of a workpiece, a sewing machine motor that serves as a driving source for vertical movement of a needle bar, and a control device that controls the sewing machine motor based on the detection result by the detection portion and performs control to maintain a constant stitch pitch. The control device lengthens a period for obtaining an output of the detection portion when the movement amount of the workpiece per unit time based on the detection result by the detection portion is decreased, and shortens the period for obtaining the output of the detection portion when the movement amount of the workpiece per unit time based on the detection result by the detection portion is increased.