Extension, free arm and auxiliary beds for overlock machine

A bed structure for an overlock machine, comprising:

• a fixed bed including a main bed having a front side defined with respect to a feed direction in which a workpiece is fed to be sewn by the overlock machine, and an extension bed having an upper surface, said extension bed being connected to a portion of the front side of the main bed;
• a main frame having a front end defined with respect to the feed direction;
• a substantially box-shaped free arm cover having an upper surface, said free arm cover being transversely slidably and removably disposed beside a throat plate with one side of the free arm cover contiguous with the front end of the main frame so as to cover a looper;
• and
• a substantially U-shaped auxiliary bed including a front portion, a side portion having a lower wall and a lower support wall extending therefrom, and a rear portion, said auxiliary bed disposed so as to surround all sides of the free arm cover, excluding the side of the free arm cover contiguous with the front end of the main frame, with the front portion of the auxiliary bed inserted in a gap between the extension bed and the free arm cover and with the lower wall and the lower support wall of the side portion in contact with the front end of the main frame, said auxiliary bed being joined to the extension bed with a horizontal land portion formed in the surface of the front portion of the auxiliary bed fitted in a horizontal groove formed in the corresponding surface of the extension bed so as to be transversely movable relative to the extension bed and so as to form a workpiece supporting surface together with the upper surfaces of the extension bed and the free arm cover.