Sewing – Elements – Presser devices
Reexamination Certificate
2000-11-04
2002-09-03
Izaguirre, Ismael (Department: 3765)
Sewing
Elements
Presser devices
Reexamination Certificate
active
06443080
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a presser foot system for sewing machine comprising a small tubular cylinder bed which is used, for example, in joining crotch sewing of underpants or drawers and joining shoulder sewing of shirts. More particularly, the invention relates to a presser foot system mounded on an interlock stitch sewing machine with which the upper edges of the ends of two fabrics to be fed in a vertical face-to-face contact are cut to an even length, and the resulting ends of the fabrics are stacked one on another on a stitch plate and then fed to a needle location for sewing the overlap portions.
2. Description of the Prior Art
When performing a sewing operation wherein the ends of two fabrics cut to a predetermined shape being stacked over a predetermined width are fed to a needle location while sewing the overlap portions, it is necessary to adjust the overlap width of the ends of the fabrics. If the sewing operator performs such adjustment by hand at a location, in the direction of sewing, before a presser foot system in which the fabrics are held and pressed against the stitch plate, a lot of labor and skill are required, resulting in poor operating efficiency. Further, difference in the degree of skill may often cause variations in the finished sewing article.
In order to omit such manual adjustment of the overlap width of two fabrics, that is, to perform such adjustment automatically, a presser foot system for sewing machine has conventionally been proposed and put into practice which has a specific construction and comprises a knife trimming mechanism and a guide means. The knife trimming mechanism cuts the edges of fabrics to be sewed into an even length, and the guide means guides the ends of the fabrics respectively to travel (move) to a needle location in order that these ends cut by the knife trimming mechanism are stacked one on another at a location before the needle location.
FIGS. 7 and 8
illustrate one particular example of known presser foot systems for sewing machine having a specific construction which comprises the above-mentioned knife trimming mechanism and guide means. Specifically,
FIG. 7
is a perspective view of the vicinity of a needle location in an interlock stitch sewing machine. A sewing machine arm
1
has at its tip a needle bar (not shown) and a presser bar
2
that are aligned before and after in the sewing direction X and are supported vertically and downwardly. A number of needles
4
are attached via a needle clamp body
3
to the lower end of the needle bar. A presser foot system for sewing machine
5
is fixedly supported to the lower end of the presser bar
2
.
The presser foot system
5
comprises (i) a pair of right and left presser feet
51
and
52
, as shown in
FIG. 8
, which are disposed before a needle location
8
of a throat plate
7
fixed on the upper surface of a small tubular cylinder bed
6
, so as to be free to make a flexible contact with the throat plate
7
, (ii) a fabric guide path
9
that is formed between the opposed surfaces of the presser feet
51
,
52
and is opened forward of the sewing direction X, (iii) a knife trimming mechanism
10
disposed in the course of the fabric guide path
9
, by which the edge portions of the ends of right and left fabrics BR and BL in a vertical face-to-face contact are fed to the fabric guide path
9
, and (iv) a guide means comprising upper and lower guides
11
and
12
which respectively guide the fabrics BR and BL cut to an even length by the knife trimming mechanism
10
to move to the needle location
8
, thereby stacking the ends of the fabrics BR and BL.
The knife trimming mechanism
10
is made up of a fixed knife
10
A and a movable knife
10
B. The fixed knife
10
A is fixed to one presser foot
51
with its cutting edge
10
a
1
(see
FIG. 9
) faced into the fabric guide path
9
. The movable knife
10
B is disposed on the side of the other presser foot
52
with its cutting edge
10
b
1
(see
FIG. 9
) faced into the fabric guide path
9
. As shown in
FIG. 7
, the movable knife
10
B is urged on its base end downwardly by a coil spring
14
and attached to the lower end of a rod
13
moving with the rotation of a main shaft (not shown) of the sewing machine, and is constructed so as to be free to rock in the directions indicated by arrows a and b crossing the fabric guide path
9
. Thereby, the movable knife
10
B is brought into a sliding contact in the plane horizontal to the upper surface of the fixed knife
10
A by the action of the coil spring
14
that is generated by movement of the rod
13
. As shown in
FIG. 9
, a contact guide piece
10
b
2
for guiding the sliding contact of the knives
10
A and
10
B is formed at one end of the movable knife
10
B in the sewing direction.
The upper surface of the presser foot system
5
is provided with a guide slot
15
that extends from the terminal part of the fabric guide path
9
to an oblique rearward of the sewing direction X, so as to be continuous with the outer edge of the presser foot
51
. By the guide slot
15
, the ends of the fabrics cut by the knife trimming mechanism
10
are guided to the outside of the presser foot
51
and then discharged, without reaching the needle location
8
.
The upper guide
11
of the guide means is disposed above the presser foot
52
and overhangs at its middle part toward the fabric guide path
9
. As the upper guide
11
approaches the needle location
8
, the amount of overhang toward the fabric guide path
9
is increased so as to be continuous with the upper guide slot
15
. The lower guide
12
is disposed under the presser foot
51
and the amount of overhang toward the fabric guide path
9
is increased as it approaches the needle location
8
, like the upper guide
11
. Also, the lower guide
12
is formed so as to be substantially horizontally opposed to the stitch plate
7
with a predetermined gap therebetween.
In the presser foot system
5
, slide plates
16
and
17
are attached to the lower surface of the paired presser feet
51
and
52
, respectively, over the entire length in the sewing direction X. The slide plates
16
and
17
ensure slide between the fabrics BR and BL held and urged against the stitch plate
7
, thereby facilitating the fabric feed operation of feed dogs (not shown). The lower guide
12
is integrally formed with the slide plate
16
on the side of the presser foot
51
.
Operation to cut the ends of fabrics to an even length and to stack one on another performed by the presser foot system
5
so constructed will be described by referring to
FIGS. 10A
to
10
E.
As shown in
FIG. 10A
, right and left fabrics BR and BL are fed to the fabric guide path
9
in such a state that their ends BRa and BLa having a predetermined width are stacked one on another. At this time, an auxiliary bar
18
may be used to hold the vertical state of the overlap portions of the fabrics BR and BL.
As shown in
FIG. 10B
, when the fabrics BR and BL fed in this state into the fabric guide path
9
reach the knife trimming mechanism
10
, the movable knife
10
B rocks in a direction to cross the fabric guide path
9
such that it is brought into sliding contact with the upper surface of the fixed knife
10
A within a horizontal plane. Thereby, the upper edges of the ends of the fabrics BR and BL are cut to an even length. In this cutting position, the upper and lower guides
11
and
12
overhang in a predetermined amount within the fabric guide path
9
. The end face of the upper guide
11
is in contact with the outer surface of the end of the resulting right fabric BR, and the end face of the lower guide
12
is in contact with the outer surface of the end of the resulting left fabric BL.
As shown in
FIGS. 10C and 10D
, as the left fabric BL of which upper edge is cut by the knife trimming mechanism
10
is fed in the sewing direction X, it is brought down to the stitch plate
7
when it is pushed from the left by the lower guide
12
in which the amount of overhang is incr
Asazuma Yoshiyuki
Matsumoto Fumio
Seiriki Tohru
Hochberg D. Peter
Holt William H.
Izaguirre Ismael
Vieyra Katherine R.
Yamato Sewing Machine Seizo Co., Ltd.
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