Abstract: An upper thread is guided to extend vertically by a pair of thread guides vertically opposted to each other. A thread take-up lever is installed so that it is horizontally reciprocated across the space between the pair of thread guides. When the thread take-up lever is reciprocated, it engages the thread positioned between the thread guides to draw it in V-form during its forward travel and stops drawing the thread to form a slack in the thread in its return travel. To prevent this slacked thread portion from clinging to the thread take-up lever, a thread holding member or thread braking member made of easily deformable material and adapted to contact the thread to thereby prevent the thread from following the movement of the thread is installed at at least one position along the path of travel of the thread engaging portion (10, 10a, 10b, 10c 50) of the thread take-up lever.

Abstract: A plurality of tension disk assemblies in an overedge sewing machine are disposed on a shaft supported for rotation around its axis and are spaced apart from each other in an axially distributed relationship. Each tension disk assembly comprises first and second tension disks forming a pair for holding therebetween a thread to be tensioned. The first tension disk is movable in opposite directions axially of the shaft, and the second disk is substantially immovable in the direction of the axis of the shaft. The resilient force of a spring acts on each first tension disk, whereby the latter is pressed against the second tension disk associated therewith. When the shaft is turned, as by a manual operating lever, this rotary motion is converted into a linear motion through a cam device. This linear motion removes the resilient force of the spring from the first tension disk. Thus, a thread tension released state is established simultaneously in the plurality of tension disk assemblies.

Abstract: A looper changeover device for a sewing maching capable of making overlocked stitches is improved by having a manually operable, rotatable selector mechanism for securing and selectively positioning a looper with respect to a looper holder and a looper driving mechanism between a first position and a second position wherein the looper can be moved along separate paths for the selective production of overlocked stitches with one needle and three threads or one needle and two threads. The rotatable selector mechanism can include a rotatable disk or dial supported by the holder and engaging a portion of the looper for positioning and securing the looper in either of the first and second positions.

Abstract: A looper for a sewing machine capable of making overlocked stitches has a unitary distal portion which is operable for the selective production of overlocked stitches with one needle and three threads or one needle and two threads. The unitary distal portion of the looper includes an upper looper portion and a spreader portion. A holder is provided in connection with driving means for supporting the looper, and a positioning arrangement is provided to selectively position the unitary distal portion of the looper in a first position for movement along a first path or in a second position for movement along a second path for the selective production of the stitches.

Abstract: A full rotary loop taker assembly comprising a loop taker (11) rotatably held in a loop taker support (1), and a driver (3) for rotatively driving the loop taker as it is rotated around a rotative axis (4) intersecting the rotative axis (12) of the loop taker. The loop taker is formed on its bottom surface wall (16) with at least three angularly spaced engaging holes (17a, 17b, 17c). The driver is formed with at least three angularly spaced projections (10a, 10b, 10c) adapted to be received in the engaging holes. During the rotation of the driver, the projections are successively received in the corresponding engaging holes in such a manner as to ensure that there is always at least one projection which has been received in the corresponding engaging hole. Further, to allow passage of an upper thread loop (23), in a predetermined angular range in the rotation of the driver the respective projections are ready to escape from the corresponding holes.

Abstract: An overedge sewing machine is adapted to perform three thread overedge stitching (STITCH TYPES 504 and 505) under the cooperating action of one needle (6) and an upper looper (15) and a lower looper (31). In addition to swing movement in the direction crossing the fabric feed direction, reciprocating movement in the fabric feed direction is selectively applied to the lower looper, whereby the front end of the lower looper is revolved around the needle. If the lower looper is revolved around the needle with the upper looper out of action, this operation provides double chain stitching (STITCH TYPE 401). Further, if the lower looper is revolved around the needle with the upper looper in action, this operation provides three thread double chain overedge stitching (STITCH TYPE 601).

Abstract: A slit (7) is formed which lies in a vertical plane and extends from an upper surface of a sewing machine frame (1) to a front surface. A tension device (5), a thread take-up spring (30), and upper and lower thread guides (23, 24) are disposed along the direction in which the slit (7) extends. A thread take-up lever (12) is installed so that it is reciprocated horizontally across the space between the pair of thread guides (23, 25). The placement of the thread in the tension device (5), thread take-up spring (30), and two thread guides (23, 24) can be attained by simply pulling the upper thread vertically downward through the slit (7). When the thread take-up lever is reciprocated, during its forward stroke it arrests the portion of the thread positioned between the two thread guides (23, 24) and draws it in V form. During its return stroke, the thread take-up lever (12) releases the thread to allow the latter to loosen in loop form.