Sewing – Elements – Frames
Reexamination Certificate
2001-03-23
2001-12-25
Izaguirre, Ismael (Department: 3765)
Sewing
Elements
Frames
C112S324000, C112S312000
Reexamination Certificate
active
06332418
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sewing machine used in hemming of J-shaped folded cloth.
2. Description of the Related Art
Usually, a sewing machine used in hemming of J-shaped folded cloth comprises, as shown in
FIG. 4
, a needle plate
102
having a portal shaped needle hole
100
and the feed dog slots
104
,
105
,
106
, and the feed dogs (omitted in
FIG. 4
) projecting and retracting on the top of the needle plate
102
from the first to third feed dog slots
104
,
105
,
106
. The portal shaped needle hole
100
has two needle drop portions
100
b
through which two needles
100
a
(see
FIG. 5
) pass. The first feed dog slots
104
,
104
of the needle plate
102
are disposed at the right and left side across the portal shaped needle hole
100
, each extending before and after the portal shaped needle hole
100
in a state parallel to the cloth feed direction F. The second feed dog slots
105
,
105
of the needle plate
102
are a pair disposed at the right and left side ahead of the portal shaped needle hole
100
in the cloth feed direction F. The third feed dog slots
106
,
106
are a pair disposed at right and left side behind the portal shaped needle hole
100
in the cloth feed direction F. The J-shaped folded cloth set on the needle plate
102
is fed in the cloth feed direction F by means of the feed dogs.
In the conventional sewing machine having the needle plate
102
and the feed dogs projecting and retracting from the feed dog slots
104
,
105
,
106
, when the feed dogs descend, a cloth end Wb of the folded portion Wa of the J-shaped folded cloth W as shown in
FIG. 5
drops into the left side second feed dog slot of the pair of right and left second feed dog slots
105
,
105
and the dropping state continues until just before the portal shaped needle hole
100
. Accordingly, the cloth end Wb of the folded portion Wa is deviated in lateral position with respect to the needle plate
102
. In this lateral position deviated state, if the folded portion Wa of the J-shaped folded cloth W is sewn near the cloth end Wb, as shown in
FIG. 5
, the spacing margin between the outlet seam end Wbb of the folded portion Waa sewn to the cloth main body WW and the seam S is not constant, and a corrugated state is formed, and the appearance of the sewn product is impaired. Besides, the cloth end Wb dropping into the left side second feed dog slot is sent by following up the side end
105
a
of the left side second feed dog slot, and, as a result, the spacing between the outlet seam end Wbb and the seam S is not as specified.
SUMMARY OF THE INVENTION
The invention is devised in the light of the above problems, and it is hence an object thereof to present a sewing machine capable of feeding the cloth by stabilizing the lateral positions of the cloth end of the folded portion when hemming the J-shaped folded cloth, and controlling the spacing between the outlet seam end of folded portion sewn to the cloth main body and the seam at a specified level so as to obtain a sewn product of excellent appearance.
To achieve the object, the sewing machine of the present invention comprises a needle plate and feed dogs. The needle plate includes a portal shaped needle hole having a needle drop portion, a pair of first feed dog slots disposed at right and left side across the portal shaped needle hole extending back and forth in the cloth feed direction of the portal shaped needle hole, a second feed dog slot disposed ahead in the cloth feed direction of the portal shaped needle hole, and a third feed dog slot disposed behind in the cloth feed direction of the portal shaped needle hole. A presser foot is disposed above the needle plate, and feed dogs move in and out from the feed dog slots of the needle plate so as to feed the J-shaped folded cloth.
As the feature of the needle plate used in this sewing machine, first, the second feed dog slot is disposed at the nearer side of the portal shaped needle hole being shifted to the right side first feed dog slot side from the center of the portal shaped needle hole, and the left side first feed dog slot of the pair of right and left first feed dog slots is extending toward the second feed dog slot side ahead in the cloth feed direction of the portal shaped needle hole, so as to be formed in a shape wide in the lateral direction. A first cross-piece of the needle plate disposed between the groove of the wide shape and the needle drop portion of the portal shaped needle hole is formed wider in the cloth feed direction than a second cross-piece of the needle plate disposed between the second feed dog slot and the needle drop portion of the portal shaped needle hole. The feed dog is composed of a main feed dog disposed in each feed dog slot behind in the cloth feed direction from the needle drop portion of the portal shaped needle hole, and a differential feed dog disposed in each feed dog slot ahead in the cloth feed direction from the needle drop portion of the portal shaped needle hole, and each differential feed dog is composed in a shape combining the first feed dog slot and second feed dog slot.
According to the present invention, when the J-shaped folded cloth is put onto the needle plate of the sewing machine, the folded cloth is fed in the cloth feed direction by collaborative action of the differential feed dog and the presser foot. At this time, the second feed dogs lot is disposed as being shifted to the right side first feed dog slot side from the center of the portal shaped needle hole, a wide slot extending from the left side first feed dog slot is formed in the needle plate portion before the portal shaped needle hole by this shifting, and the differential feed dog is formed in the shape of combining the first feed dog slot including this wide slot and second feed dog slot, and therefore the cloth can be fed securely without causing deviation in the lateral position due to drop of the cloth end of the folded portion of the J-shaped folded cloth in the second feed dog slot before the needle drop portion. Further, when the folded cloth is fed forward to just before the needle drop portion of the portal shaped needle hole, the cloth end of the folded portion is securely supported by the first cross-piece formed widely in the cloth feed direction, and the cloth can be fed up to the needle drop portion while maintaining the specified lateral position without the cloth end being fed along the side end of the second feed dog slot.
Thus, when hemming a J-shaped folded cloth, it is capable of feeding the cloth by stabilizing the lateral positions of the cloth end of the folded portion, and controlling the spacing between the outlet seam end of folded portion sewn to the cloth main body and the seam at a specified level, and therefore it is effective to obtain a sewn product of excellent appearance.
REFERENCES:
patent: 4072116 (1978-02-01), Nagy
patent: 4430878 (1984-02-01), Dispennett et al.
patent: 4934293 (1990-06-01), Yokota et al.
patent: 5311831 (1994-05-01), Fieschi
Izaguirre Ismael
Jones Tullar & Cooper P.C.
Pegasus Sewing Machine Mfg. Co. Ltd.
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