Abstract: A thread tensioning device for a sewing machine comprises a limit member fixed on the sewing machine, and an elastic pulling member mounted on the limit member. The pulling member includes an elastic extension portion which is movably disposed on the limit member. The pulling member further includes a free end formed with a hook-shaped thread pulling portion. The limit member is provided with two limit portions defining a space for passage of the thread. During a thread loosening operation, the thread will be moved within the space defined by the two limit portions while being pulled by the thread pulling portion of the pulling member, so that the thread pulling portion can provide a proper amount of tension to the thread timely, thus avoiding the occurrence of skip stitch and ensuring the sewing quality.

Abstract: A thread take-up lever for a sewing machine is mounted on the sewing machine and can prevent a thread from disengaging from a thread-receiving portion. The thread take-up lever is disposed with a C-shaped thread-receiving portion having an open recess. Adjacent to the open recess is provided at least one positioning portion for fixing a thread-stopping member. One end of the thread-stopping member is fixed to the positioning portion, and an elastic stopping portion extends from the other end of the thread-stopping member. The stopping portion is formed with a free end abutted against an inner periphery of the open recess. The free end can be pushed away by the thread, and then the free end will automatically return to its original position immediately to abut against the open recess again, thus forming a structure to prevent the thread from disengaging from the thread-receiving portion.

Abstract: A pressure adjustment structure for a presser foot of a sewing machine, wherein one end of a horizontal arm of the sewing machine is disposed with a presser bar of the presser foot, and an elastic member is mounted on the presser bar. The end of the horizontal arm is provided with a main supporting frame, so that the pressing member slides on the main supporting frame with a pressing body and a guiding member, and one end of the pressing member presses an elastic member. In addition, the pressing body extends towards and is driven by an adjustment element of the main supporting frame, so that the pressing member driven by the pressing body slides on the main supporting frame to press the elastic member so as to provide different pressure. A second supporting frame is disposed on the main supporting frame to connect with the horizontal arm.

Abstract: A thread take-up lever for a sewing machine is mounted on the sewing machine and can prevent a thread from disengaging from a thread-receiving portion. The thread take-up lever is disposed with a C-shaped thread-receiving portion having an open recess. Adjacent to the open recess is provided at least one positioning portion for fixing a thread-stopping member. One end of the thread-stopping member is fixed to the positioning portion, and an elastic stopping portion extends from the other end of the thread-stopping member. The stopping portion is formed with a free end abutted against an inner periphery of the open recess. The free end can be pushed away by the thread, and then the free end will automatically return to its original position immediately to abut against the open recess again, thus forming a structure to prevent the thread from disengaging from the thread-receiving portion.

Abstract: A pressure adjustment structure for a presser foot of a sewing machine, wherein one end of a horizontal arm of the sewing machine is disposed with a presser bar of the presser foot, and an elastic member is mounted on the presser bar. The end of the horizontal arm is provided with a main supporting frame, so that the pressing member slides on the main supporting frame with a pressing body and a guiding member, and one end of the pressing member presses an elastic member. In addition, the pressing body extends towards and is driven by an adjustment element of the main supporting frame, so that the pressing member driven by the pressing body slides on the main supporting frame to press the elastic member so as to provide different pressure. A second supporting frame is disposed on the main supporting frame to connect with the horizontal arm.

Abstract: The present invention refers to a needle holder of multiple needles, the needle holder is connected with a needle bar on one end and equipped with a needle receiver with several open needle accommodating parts on the other end, so that it is convenient to process and manufacture. With cooperation of a needle retainer, the needle accommodating part of the needle receiver can become a closed structure to allow the ends of the needles to insert and be fixed on position by a needle fastening member on the needle retainer. Wherein, due to the open structure of the whole needle receiver of the needle holder, the manufacture is more precise and accurate, in addition, the processing, maintenance and replacement are more convenient, so as to become a structure of high precision and easy manufacture.

Abstract: A needle support for securing needles to a sewing machine includes a block having a flat surface for engaging with the flat portions of the needles. A cap is secured to the block and has one or more channels for engaging with the curved portion of the needle. The block may include one or more grooves and each having a flat surface for engaging with the flat portions of the needles. The block may include one or more curved grooves formed in the opposite surface for engaging with the curved portions of the needles whose flat portions are engaged with the flat surface of another cap.

Abstract: A driving mechanism for a sewing machine includes a rotatable shaft coupled to one or more needles for moving the needles upward and downward in a reciprocating action. A rotary looper is rotatably secured to the sewing machine at a vertical axle and is coupled to the shaft for allowing the shaft to actuate the needles and the rotary looper simultaneously. A rod is vertically secured in the sewing machine and coupled to the rotary looper for rotating the rotary looper. Two bevel gears are secured to the rod and the shaft for allowing the shaft to rotate the vertical rod.

Abstract: A thread tension device for a sewing machine includes two or more pairs of discs for engaging with two or more threads. Two or more tension applying members are engaged with the pairs of discs for applying a biasing force against the pairs of discs. Two or more micro-adjusting mechanisms are engaged with the tension applying embers for adjusting the biasing force against the pairs of discs. An actuator is engaged with the micro-adjusting mechanisms for actuating the micro-adjusting mechanisms simultaneously.

Abstract: A looper device includes a rod slidably supported in a sewing machine and allowed to move up and down. A looper is secured on the upper end of the rod and includes a hole formed in the front end and includes a support formed on the rear portion. A lever is coupled to the support at a pivot shaft and includes an extension extended from the front end for engaging with the front end of the looper and forming a shoulder which may engage with and may feed a thread upward. The lever includes a member for positioning the lever relative to the looper.

Abstract: A sewing machine includes two rods rotatably and slidably supported in the sewing machine and two lower loopers secured on the rods. A spindle is coupled to the rods by an eccentric and coupling members for rotating the rods and the lower loopers. One of the lower loopers may be moved axially together with one rod to which a pawl is rotatably supported, The pawl may be selectively engaging with the other rod for allowing the pawl to selectively moving the other rod axially and for allowing the lower loopers to perform two double chain stitchings.

Abstract: A driving assembly includes a shaft pivotally supported in a sewing machine. A rod is movable up and down and includes a looper secured on top. A follower is secured to the shaft and includes a post. A block is slidably engaged on the post and includes a pivot axle pivotally coupled to the rod for moving the rod up and down. The block is adjusted along the rod for adjusting the distance between the pivot axle and the shaft and for adjusting a moving stroke of the looper. The rod and the looper are stopped when the pivot axle is moved to coincide with the shaft.

Abstract: A shaft coupling mechanism for a sewing machine includes an eccentric secured on a rotatable shaft and includes a ring engaged on the eccentric so as to be moved up and down by the eccentric. The ring has a downward extending bar. A block is rotatably secured to the lower end of the bar and rotatable relative to the bar about a pin. The block includes a rod secured to a spindle so as to rotate the spindle in an oscillating action without a ball joint. The rotational movement of the block relative to the bar will not affect the movement of the bar.

Abstract: A thread tensioning device for a sewing machine includes two plates engaged on a shaft and a spring for biasing the plates toward each other in order to clamp a thread. The plates each includes a thread receiving portion and each includes another portion opposite to the thread receiving portion. A projection is engaged between the opposite portions so as to separate the opposite portions away from each other and so as to form a closely contacted outer peripheral portion in the thread receiving portions, and in order to force the thread toward the shaft.

Abstract: A thread tension device includes a pair of discs engaged on a shaft and a spring for biasing the discs to clamp a thread. A follower is threadedly engaged on the shaft for adjusting the spring. A barrel is engaged with the follower so as to rotate the follower. A cap is rotatably engaged on the barrel. A latch is slidably engaged in the barrel for engaging the barrel with the cap so as to allow the barrel and the cap to rotate in concert when the latch is engaged with the cap. The barrel is allowed to rotate freely relative to the cap when the latch is disengaged from the cap.

Abstract: A needle plate for a sewing machine includes an opening formed in one side portion. On or more tongues may be secured to the needle plate and extended inward of the opening so as to conduct various kinds of sewing operations. A bracket is secured to the needle plate and includes a channel. A lever is slidably engaged in the channel and includes another tongue movable away from the previous tongue and movable toward the position located beside the previous tongue so as to form another tongue.

Abstract: A sewing machine includes a pair of rods slidably disposed in the base, the rods are parallel with each other, an accessory box having two or more protrusions extended downward for fixing to the rods such that the accessory box moves in concert with the rods, the accessory box is movable inward and outward of the base in order for accommodating accessories of the sewing machine.

Abstract: A sewing machine presser foot includes a presser pivotally coupled to the presser foot, a casing secured to the presser foot, a release handle pivotally coupled to the presser foot, a presser pivotally coupled to the presser foot, a spring having one end engaged with the presser in order to depress the presser and the other end engaged in the casing. The casing and the other end of the spring are separated from the release handle such that the users will not be hurt by the spring when the users actuate the release handle.