Sewing – Stitch forming – Zigzag
Reexamination Certificate
2001-05-31
2003-09-09
Izaguirre, Ismael (Department: 3765)
Sewing
Stitch forming
Zigzag
C112S162000, C112S165000
Reexamination Certificate
active
06615757
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is based on Japanese Application 2000-163101, filed on May 31, 2000, which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an over lock sewing machine.
2. Discussion of the Background
Recently, a demand for a luxurious embroidery sewing machine has been increasing significantly according to a diversification of the individuals. In addition to a lock stitch sewing machine, a demand for an expansion of a zigzag decorative stitch type has been also increasing. Besides, as for an over lock sewing machine, a double-thread chain stitch bottom decoration function by a plurality of needles is added to comply with such demands. As a result, an application for making a decorative stitch with a seamy looper thread side has became popular.
In a general home sewing, the over lock sewing machine is suitable far a whipstitch but a zigzag stitch by the lock stitch sewing machine is substituted for the whipstitch instead of buying two different type sewing machines. In most cases, since a single lock stitch sewing machine is used for various purposes, a finish of stitching is inferior compared to that of a general clothing. Accordingly, in order to further improve the finish, it is general to purchase an over lock sewing machine as a second sewing machine taking account of a financial strain, a storage space, a work space, and a difficulty of an alternative usage. Further, in recent years, a knit material having large stretch has been used more and more. Accordingly, in a plain seam process, the finish of the double-thread chain stitch is superior to the finish of the lock stitch in most cases.
As a result, a technology which combines the functions of the lock stitch sewing machine and the over lock sewing machine has been developed. For instance, as a first conventional art, a sewing machine adding a lock stitch function to an over lock sewing machine is disclosed in a Japanese Patent Application published in 1996 as Toku Kai Hei 8-24451. The sewing machine is provided with a single needle bar and loopers and a shuttle body are positioned adjacent to each other.
As a second conventional art, a combined sewing machine is disclosed in a Japanese Patent Application published in 1981 as Toku Kai Sho 56-148378. The combined sewing machine is provided with an over lock function at a front surface of a leg portion of a lock stitch sewing machine. When in use of the over lock, the over lock function is moved to the lock stitch position.
As a third conventional art, a combined sewing machine is disclosed in a Japanese Patent Application published in 1979 as Toku Kai Sho 54-76347. The combined sewing machine is provided with an over lock function at a rearward of a leg portion of a lock stitch sewing machine. When in use of the over lock, the lock stitch sewing machine is inverted for using the over lock sewing machine.
However, the sewing machine in the first conventional art can make an over-edge chain stitch, a double-thread chain straight stitch, and a straight lock stitch but can not make a zigzag stitch. Various decorative stitches can not be achieved by the sewing machine. In the lock stitch sewing machine, the shuttle body is desirably positioned closest to a lower surface of a throat plate in order to assure the stitch function. In the conventional art, the shuttle body needs to be positioned lower than a bottom dead point of the over-edge chain needle in order to avoid the interference with the over-edge chain needle. Accordingly, the amount of the absorbing thread of the shuttle body is increased and the stitch function might be defected
Further, in proportion to the position of the shuttle body, the lower end of the lock stitch needle is positioned lower than the over-edge chain needle. When the same, type needles are used, the lower end of the needle holder holding the upper end portion of the needles also has the same step and the pressure increasing amount is limited in response to the step. In order to assure the pressure increasing amount with the over-edge chain needle, a special long needle in response to the step as the lock stitch needle needs to be used. When the long needle is used, the defects caused by a needle bend might be generated. Further, the threading the looper arranged at the rearward of the shuttle body might be difficult.
Moreover, a stroke of a needle thread take ups taking up the absorbing thread amount of the shuttle body is increased. Besides the increased stroke, the increase of the moving members might be a factor of a noise and oscillation malfunction. Further, materials such as a shuttle body, a needle thread take ups, a stitch balancing thread tension, and a sewing machine guide member for forming a seam of a lock stitch need to be added independently. As a result, the cost might be increased drastically.
The sewing machine in the second conventional art can make a straight lock stitch, a zigzag lock stitch, an over-edge chain stitch, and a double-thread chain straight stitch, but can not make a double-thread chain zigzag stitch. Various decorative stitches can not be achieved by the sewing machine. Further, materials such as a shuttle body, a needle thread take ups, a stitch balancing thread tension, and a sewing machine guide member for forming a seam of a lock stitch need to be added independently. As a result, the cost might be increased drastically. Moreover, a driving changeover clutch for the lock stitch and the over-edge chain stitch is added and the cost might be increased drastically. Further, when the over-edge chain stitch is made, the cloth feeding might be difficult due to materials such as a pressure foot and needles for the lock stitch provided at the rearward.
The sewing machine in the third conventional art can also make a straight lock stitch, a zigzag lock stitch, an over-edge chain stitch, and a double-thread chain straight stitch, but can not make a double-thread chain zigzag stitch. Various decorative stitches can not he achieved by the sewing machine. Further, materials such as a shuttle body, a needle thread take ups, a stitch balancing thread tension, and a sewing machine guide member for forming a seam of a lock stitch need to be added independently. As a result, the cost might be increased drastically. Moreover, a driving changeover clutch for the lock stitch and the over-edge chain stitch is added and the cost might be increased drastically.
Further, when the over-edge chain stitch is made, the sewing machine is difficult to operate since the sewing machine needs to be inverted.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an over lock sewing machine which can make various decorative stitches with the over-edge chain stitch function and the zigzag stitch function and which is low in cost.
In order to solve above technical problems, an over lock sewing machine for forming seams of an over-edge chain stitch and a double-thread chain stitch on a work cloth is provided with a needle bar holding a plurality of needles for forming a seam by a vertical reciprocating movement, a plurality of loopers and a needle bar transmitting mechanism moving the needle bar in approximately orthogonal direction relative to a cloth feeding direction of the work cloth and the vertical reciprocating direction of the needle bar.
According to an aspect of the present invention, since the needle bar can be moved in approximately orthogonality direction to the cloth feeding direction of the work cloth and the vertical reciprocating direction of the needle bar by the needle bar transmitting mechanism, the over lock sewing machine can make various decorative stitches with the over-edge chain stitch function and the zigzag stitch function. By only providing the needle bar transmitting mechanism, various decorative stitches can be realized. Accordingly, the over lock sewing machine can make various decorative stitches. The over lock sewing machine capable with operation as well as th
Aisin Seiki Kabushiki Kaisha
Izaguirre Ismael
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