Abstract: A thread tension adjustment device of multi-needle sewing machine including: a fixing rack fixed on a housing of the sewing machine; multiple frame bodies side by side fixed on the fixing rack; multiple thread tension adjustment units mounted on the frame bodies, each thread tension adjustment unit serving to resiliently clamp a thread, multiple thread-loosening slide boards being respectively slidably disposed on the frame bodies, each thread-loosening slide board having multiple wedge sections; and a link pivotally connected with the thread-loosening slide boards for driving the thread-loosening slide boards to move the wedge sections thereof toward the corresponding thread tension adjustment units to release the threads clamped by the thread tension adjustment buttons of the thread tension adjustment units.

Abstract: A take-up cam phase adjustment structure of looper thread take-up apparatus of a sewing machine includes a rotary shaft rotatablly mounted in the sewing machine. A thread-guiding plate mounted on the housing for correspondingly pressing a stitching thread against the rim of the take-up cam. A transmission mechanism connected between the lower driving shaft and the rotary shaft. The transmission mechanism includes a driven wheel rotatablly mounted on the rotary shaft. The take-up cam phase adjustment structure includes a locking member for locking the driven wheel on the rotary shaft and a turning section disposed at one end of the rotary shaft. After the second locking member is unscrewed and loosened, by means of rotating the turning section, the relative radial positions between the take-up cam and the lower driving shaft is drivingly adjustable.

Abstract: A directly motor-driven structure of a sewing machine, including: a middle rotary shaft pivotally mounted in a middle section of the housing between the upper and lower driving shafts. A first transmission mechanism connected between the lower driving shaft and the middle rotary shaft. A second transmission mechanism connected between the upper driving shaft and the middle rotary shaft. The first transmission mechanism is spaced from the lower stitching needle by a first length. The second transmission mechanism is spaced from the upper stitching needle by a second length. The second length is smaller than the first length, whereby the sewing machine is formed with a recessed installation space adjacent to the second transmission mechanism. A driving motor is installed in the recessed installation space and directly fixedly connected with the upper driving shaft.

Abstract: An oblique thread-guiding link of a sewing machine, including a swing arm having a front swing arm and a rear swing arm and formed with a central shaft hole. A pivot shaft is fixedly fitted in the shaft hole of the swing arm. Two ends of the pivot shaft are obliquely pivotally mounted in two opposite sidewalls of the housing of the sewing machine. One end of the pivot shaft protrudes from the housing of the sewing machine. The front end of the front swing arm is positioned above a needle holder mechanism and aligned and coupled therewith. The rear end of the rear swing arm is positioned above a driving mechanism and aligned and coupled therewith. One end of a thread-guiding fixing seat is fixedly connected with the protruding end of the pivot shaft and can be swung along with the swing arm.

Abstract: A knife track adjustment structure of a thread cutter of a sewing machine includes a front guide board bridged over the base board with an upper and a lower ends of the front guide board locked on the base board. The front guide board up and down adjustably displaceable on the base board. A guide is disposed under the middle section of the front guide board, a guide pin being sequentially passed through a hook rod arm and a knife arm. A swing arm, a first end of the swing arm being pivotally connected with the base board, a pin being connected with the bottom of a second end of the swing arm. The pin is sequentially passed through the hook rod arm and pivotally connected on the knife arm. A spring compressed between the swing arm and the base board helps in restoring the knife arm and hook rod arm.

Abstract: A looper thread take-up apparatus of a sewing machine, which is mounted near a side of the machine bed distal from an operator and is adjacent to the lower knotting hook. The looper thread take-up apparatus includes a rotary shaft. One end of the rotary shaft is driven by the lower driving shaft, while the other end of the rotary shaft is coupled with the thread take-up cam.

Abstract: A sewing machine includes a first and a second lower rotary shafts coaxially coupled with each other by a shaft and disposed in a lower housing of the sewing machine. A looper thread take-up cam includes a first and a second take-up cam plates slidably key-fitted on the second lower rotary shaft. A slide interval is defined between the take-up structure and the shaft coupler, whereby the second cam plate can slide along the second lower rotary shaft to the slide interval and separate from the first cam plate for easily clearing up the tangling thread. A guide plate of the take-up structure is movably connected with a bracket of the lower housing, whereby by means of changing the position of the guide plate relative to the second lower rotary shaft, the take-up timing can be adjusted.

Abstract: A looper thread take-up apparatus externally added to outer end of lower driving shaft of a sewing machine. A thread guide structure and a looper thread tension adjustment structure are mounted on outer face of the housing of the sewing machine and are adjacent to the outer end of the lower driving shaft of the sewing machine. The thread take-up cam is detachably disposed at the outer end of the lower driving shaft and rotatable along therewith. In case the looper thread breaks and tangles with the thread take-up cam, the thread take-up cam can be directly detached from the outer end of the lower driving shaft so that it is easy and convenient to clear up the tangling thread from outer side of the sewing machine.

Abstract: Looper thread take-up structure of sewing machine capable of very easily clearing up tangling thread, including: a rotary shaft; a first and a second take-up cam plates each having a cam outer rim and a non-circular shaft hole, the first and second take-up cam plates being detachably keyed on the rotary shaft; and a spacing ring having a through hole and detachably fitted on the rotary shaft between the first and second take-up cam plates for spacing the same. In case a stitching thread is accidentally tangled on the spacing ring, the first and second take-up cam plates can be separated from each other for quickly and easily clearing up the tangling thread.