Sewing – Work manipulating – Guides
Reexamination Certificate
2000-05-04
2001-07-10
Izaguirre, Ismael (Department: 3765)
Sewing
Work manipulating
Guides
C038S143000
Reexamination Certificate
active
06257158
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a sewing machine for sewing edge hems of an upper fabric and a lower fabric together that are fed to a needle drop point in an overlapped manner, and particularly to a sewing machine equipped with an uncurling device for straightening curls formed in the edge hems.
In performing sewing by using an overlock sewing machine for overedge-chain stitching edge hems of an upper fabric and a lower fabric that are fed to a needle drop point in an overlapped manner, particularly when the upper fabric and lower fabric are, i.e., knitted fabrics that tend to exhibit a tendency to curling, it would often be the case that both fabrics were fed to the needle drop point with their edge hems being curled to outside or inside and sewn together with these edge hems being in flapped conditions.
Such sewing causing degradations in qualities of obtained sewn articles, operators would manually straighten curls in the edge hems prior to feeding them into the needle drop point when performing sewing with the overlock sewing machine, which resulted in a great deal of work for this straightening. Further, in case the upper fabric and lower fabric are knitted materials or the like that are of rich elasticity, a drawback was presented in that high skill was required for straightening the curls without being accompanied by expansion of these fabrics.
An uncurling device that has been devised with the aim of solving these problems is disposed in Utility Model Examined Publication No. 7-44310(1995) co-owned by the applicant of the present invention, wherein the device is employed by being attached to a front portion of a needle drop point of a sewing machine for performing uncurling as once it had been manually performed by an operator.
Manual uncurling is performed through the following steps: a finger is inserted between the upper fabric and the lower fabric; other fingers are respectively placed on an upper surface of the upper fabric and a lower surface of the lower fabric for pinching the upper fabric and the lower fabric at proximities to their edge hems; and these pinched fabrics are fed to the needle drop point while the both edge hems are stretched by the fingers, thereby the curled portions are straightened (uncurled). The above uncurling device is arranged in that a plurality of straightening pieces that respectively simulate those fingers as used in the above manual operations is provided, in that the upper fabric and the lower fabric are pinched between these pieces, therefore uncurling is performed as feeding of both of the fabrics while the edge hems are stretched by the simulated fingers.
However, the uncurling device as disclosed in the above Utility Model Examined Publication 7-44310 is of complicated arrangement comprising the above plurality of straightening pieces (simulated fingers) and further comprising a mechanism for moving each of the straightening pieces up and down separately to pinch the upper fabric and lower fabric appropriately. Thus, the whole mechanism requires a bulky space in a front portion of the sewing machine.
Curls at the edge hems of fabrics that need to be straightened include outside curls with curls being formed at the edge hems of upper fabric or lower fabric in directions facing away from each other as well as inside curls with curls being formed in directions approaching towards each other. A drawback was consequently presented in that in the above uncurling device, forms for pinch-holding between the straightening pieces needed to be varied in accordance with combinations of curling shapes of the upper fabric and lower fabric and in that a great deal of work was required for setting upper fabric and lower fabric before sewing.
BRIEF SUMMARY OF THE INVENTION
The present invention has been made in view of the above problems, and it is an object of the present invention to provide a sewing machine with uncurling device capable of reliably straightening curls at edge hems of fabrics to be fed to a needle drop point in an overlapped manner regardless of shapes of these curls, and of simple arrangement requiring no troublesome work for setting the fabrics to be ready for uncurling.
A sewing machine with uncurling device of the first aspect according to the present invention is characterized by comprising: a separating plate, placed at front side of a needle drop point to be inserted between an upper fabric and a lower fabric that are fed to the needle drop point with respective edge hems being overlapped, for separating the edge hems in vertical directions; and a suction tube having an air-intake whose opening is opposing to the tip of the edge hems and whose opening is placed across the upper and lower surfaces of the separating plate, wherein curls at the edge hems of the upper fabric and lower fabric are straightened by using air flow sucked into the air-intake of the suction tube which is connected to an air-suction source.
According to the present invention, the upper fabric and lower fabric fed to the needle drop point are separated by the separating plate being inserted between these fabrics, and upon suction of air by the suction tube, ambient air is sucked through the air-intake whose opening is placed across the upper surface and the lower surface of the separating plate. In this manner, the curls at edge hems of the upper fabric and lower fabric are separated by the separating plate are pulled by the air flow towards the air-intake and are thus straightened.
The sewing machine with uncurling device of the second aspect according to the present invention is characterized in that the separating plate includes: an action piece being inclined with its tip end facing forward; and guide tips attached to both surfaces of the action piece with their thicknesses descending toward the tip end of the action piece.
According to this invention, a forwardly inclining action piece is provided at the tip end of the separating plate with its thickness decreasing toward the tip end, wherein the preliminarily placed upper fabric and lower fabric are separated by sliding guidance of the action piece while feeding these fabrics, and thus the fabrics are reliably introduced to above and below the separating plate. The decrease in thickness at the tip end of the action piece is achieved by the guide tips having sloped surfaces on one side thereof that are attached to both upper and lower surfaces of the action piece, wherein appropriate guidance is performed by adjusting positions of the guide tips on the action piece.
The sewing machine with uncurling device of the third aspect according to the present invention is characterized by further comprising: a guide lever, placed in front of the separating plate, for guiding either or both of an upper surface of the upper fabric and a lower surface of the lower fabric.
According to this invention, a guide lever disposed in a front position of the separating plate is made to abut against either or both of the upper surface of the upper fabric and the lower surface of the lower fabric, therefore it preliminarily guides these fabrics to straighten outside curls.
Furthermore, the sewing machine with uncurling device of the fourth aspect according to the present invention is characterized by further comprising: an adjustor for adjusting flow rate of air sucked into the suction tube.
According to this invention, it is provided with an adjustor for adjusting flow rate of air sucked into the suction tube, and by performing adjustments of suction rate of air in accordance with types or thicknesses of the fabrics, curls at edge hems can be reliably straightened.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.
REFERENCES:
patent: 3735512 (1973-05-01), Ross
patent: 4186674 (1980-02-01), Conner, Jr.
patent: 4590876 (1986-05-01), Mencke et al.
patent: 4928610 (1990-05-01), Akutsu
patent: 5046272 (1991-09-01), Vogt et al.
patent: 5437238 (1995-08-01), Price et al.
patent: 744310
Asazuma Yoshiyuki
Inoue Tadanori
Birch & Stewart Kolasch & Birch, LLP
Izaguirre Ismael
Yamato Mishin Seizo Kabushiki Kaisha
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