Overlock sewing machine

摘要

An overlock sewing machine includes a main shaft fixing operating arm provided with a shaft pin engaging portion that engages with a fixing inner shaft pin and an arm provided to be operable by a user which are integrally rockable within a specified range, and further includes a main shaft fixing operating spring which urging direction is switched in both directions of an rocking direction by exceeding a neutral point by the rocking movements of the main shaft operating arm and the arm.

主权项

1. An overlock sewing machine comprising:
at least one looper including an receiving opening for receiving a looper thread and having a hollow structure through which the looper thread passes; a thread inserting opening into which the looper thread is inserted that is to be inserted to the looper; a looper conduction pipe that guides the looper thread inserted into the thread inserting opening towards the receiving opening; a slide pipe provided between the looper conduction pipe and the receiving opening and which one end is fitted to the looper conduction pipe in a freely slidable manner while its other end is provided to be movable between a threading position at which it is connected to the receiving opening and a sewing executing position at which the other end is separated from the receiving opening; a slide member which is a member that holds the slide pipe and that moves between the threading position and the sewing executing position together with the slide pipe, having a long hole portion that extends along the moving direction and a wide hole portion that is formed in connection with the long hole portion and which width is formed to be larger than the width of the long hole portion; a slide member spring for urging the slide member and the slide pipe towards the receiving opening side; a main shaft that is rotationally driven; a main shaft fixing plate that is fixed to the main shaft and that includes a notch at an outer peripheral position corresponding to a threading phase at which the receiving opening is at a position at which it is connectable to the other end of the slide pipe; a first shaft which is an axial member which one end is provided to be movable between an engaging position at which it engages with the notch for fixing the main shaft at the threading phase and a retracted position at which it is completely separated from the main shaft fixing plate, comprising a small diameter portion and a large diameter portion at the other end thereof that respectively engage with the long hole portion and the wide hole portion of the slide member, wherein the position of the sliding member is maintained at each of the threading position and the sewing executing position through the engagement of the small diameter portion and the large diameter portion with the long hole portion and the wide hole portion; a second shaft that is provided to be relatively movable along an axial direction of the first shaft; a shaft spring for urging the first shaft and the second shaft in mutually separating directions; a shaft pin that is provided at the second shaft to project from the second shaft or that engages with the second shaft to be integrally movable in an axial direction of the second shaft; an engaging portion that is provided at the first shaft to engage with the shaft pin and/or the second shaft to receive force to move the first shaft towards the main shaft fixing plate side; a rocking lever portion including a main shaft fixing operating arm portion provided with a shaft pin engaging portion that engages with the shaft pin or with the shaft pin and a main shaft fixing lever portion provided to be operable by a user and being rockable within a specified range; and a main shaft fixing operating spring which urging direction is switched to both rocking directions of the rocking lever portion by exceeding a neutral point through rocking operations of the rocking lever portion.