Method and apparatus for attaching a zipper to a garment

A method and apparatus for attaching a zipper when a zipper is attached to a garment which provides a flap to cover the zipper attached thereto, conducted such that a "perfect stitch" line appears on the garment surface and a "hitch stitch" line is covered by the garment flap. Thereby, the quality of stitching work is not degraded.

BACKGROUND OF THE INVENTION 
This invention relates to a method of attaching a zipper to a garment and, 
more particularly, the invention is applicable where the garment provides 
a flap to cover a zipper attached thereto. 
Generally, when a zipper is attached to a skirt or trouser, a flap is 
provided to cover the zipper and is formed by turning and overlapping some 
portion of garment material. Referring to FIG. 5 and FIG. 6, one 
conventional method of attaching a zipper to a garment will be explained. 
Referring to FIG. 5A and FIG. 5B, a zipper F has a slider S and two zipper 
tapes FT.sub.1, FT.sub.2. The two zipper tapes FT: and FT.sub.2, are 
connected by a bottom portion FT.sub.12. Referring to FIG. 5B, the flap Wf 
is formed by turning and overlapping a front cloth W.sub.1 and the flap Wf 
is placed on the zipper tape FT.sub.1. A front cloth W.sub.2, is turned 
and overlapped and is placed on the zipper tape FT.sub.2. 
Referring to FIG. 6A, the above-mentioned workpiece is placed on a sewing 
machine table Mt. Referring to FIG. 6B, the flap Wf and the zipper tape 
FT.sub.1 are stitched. Referring to FIG. 6C, when the stitch line reaches 
to the bottom FT.sub.12, the sewing machine is stopped in the needle-down 
position and the workpiece is rotated by 90 degrees in the direction of 
arrow "a". 
Referring to FIG. 6D, the sewing machine is started again such that the 
bottom FT.sub.12, is sewed to the flap Wf and the sewing machine is 
stopped in the needle-down position. Then the workpiece is rotated by 90 
degrees in the direction of arrow "b" in FIG. 6D. Referring to FIG. 6E, 
the sewing machine is started again and the workpiece is fed in the 
direction of the arrow in FIG. 6E until the stitch line reaches the 
tip-end portion of the front cloth W.sub.2. Referring to FIG. 6F, when the 
stitch line reaches the end of the front cloth W.sub.2, the sewing machine 
is stopped and the thread is cut. Thus, the zipper is attached to the 
garment. 
As described above, the operator has to rotate the workpiece at each 
stitching line corner, so the stitch line S.sub.1 S.sub.2 S.sub.3 is 
performed by constantly feeding the workpiece forward. Thereby, each 
stitch line is a so-called "perfect stitch". 
Referring to FIG. 7, it is apparent that the stitch pitch forms "perfect 
stitch" Sp when the workpiece is fed forwardly, and forms "hitch stitch" 
Sh when the workpiece is fed reversely. The merits of this conventional 
method are that 21 each stitch line is a "perfect stitch" but the demerits 
are that the operator has to rotate the workpiece twice. Further, the 
operator has to stop the needle in the needle-down position when the 
machine is stopped and such manual work lowers productivity. 
Recently, an automatic zipper attaching machine which eliminates the two 
rotations of the workpiece has been developed, such that the workpiece is 
set in a frame and is moved in the X-Y direction accordingly. Since the 
rotation work is eliminated, if the left zipper tape FT.sub.1 is sewed in 
forward feed, the right zipper tape FT.sub.2 will be sewed in reverse 
feed. So, in this case, the right side stitch line will be hitch stitched 
and such a hitch stitched line degrades the quality of stitching work and 
the commercial value is lowered. 
Referring to FIG. 7, when the workpiece W is fed forward, the stitch line 
will be a perfect stitch Sp, and when the workpiece is fed reverse, the 
stitch line will be a hitch line Sh. It is generally apparent that hitch 
stitch appearing on the garment surface degrades its commercial value, so 
how to automatically attach a zipper without hitch stitch lines and how to 
conceal hitch stitch lines are problems requiring solution. 
SUMMARY OF THE INVENTION 
With the foregoing in mind, it is an object of this invention to provide an 
improved method and apparatus for attaching a zipper to a garment. 
Referring to FIG. 4C, when a flap Wf is provided to cover a zipper F, a 
stitch line S.sub.1 appears at the garment surface, while a stitch line 
S.sub.3 is covered by the flap and is concealed. So, the stitch line 
S.sub.1 shall be stitched by feeding forwardly and the stitch line S.sub.3 
shall be stitched by feeding reversely, such that no hitch stitch lines 
appear on the garment surface. 
According to the present invention, a zipper is sewed to a garment without 
degrading the garment's commercial value and rotation of the workpiece 
twice is eliminated. An existing sewing machine can be easily modified to 
conduct the present invention and resultantly the productivity will be 
highly Promoted.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring to drawings from FIG. 1 to FIG. 4, one referred embodiment of the 
Present invention will be explained. 
Referring to FIG. 1 and FIG. 3 an automatic zipper attaching machine 
applied with the present invention will be explained. Numeral 1 denotes a 
sewing machine, numeral 2 denotes a needle bar, numeral 3 denotes an X-Y 
table, numeral 4 denotes a X-Y driver, numeral 5 denotes a throat plate. 
The X-Y table 3 is arranged to move in the direction of X-Y along the 
surface of the throat plate 5 by the X-Y driver 4. Numeral 6 denotes a 
set-table which moves in the direction of arrow "A". Numeral 7 denotes a 
casset which comprises two openable frames 7a, 7b. These openable frames 
7a, 7b clamp the workpiece. The workpiece is moved in direction of arrow 
"B" such that the workpiece is set for stitching. 
FIG. 2 is a block diagram which illustrates how the X-Y driver 4 is 
controlled. Referring to FIG. 2, numeral 8 denotes a CPU, numeral 9 
denotes a ROM which stores control programs, numeral 10 denotes a RAM 
which stores input data from input device 11 shown in FIG. 3. Numeral 12a 
denotes an X-motor, numeral 12b denotes a Y-motor, and these are set in 
the X-Y driver 4. Numeral 13 denotes a main motor installed in the sewing 
machine 1 (FIG. 1). Both X-motor 12a and Y-motor 12b are controlled by the 
CPU 8. 
Referring to FIG. 4, a method of attaching a zipper to a garment according 
to the present invention using the aforementioned sewing machine will be 
explained hereinafter. An operator sets a front cloth W and a zipper F on 
the frame 7b as shown in FIG. 5B, and then the upper frame 7a is closed 
such that the front cloth W and the zipper F are clamped by the frames 7a 
and 7b. Then the set-table 6 is moved in direction of "A" until it reaches 
to the throat plate 5 as shown by the chain line in FIG. 1. Then, the 
casset 7 is slid on the X-Y table 3 and is fixed on the X-Y table 3. Thus 
the front cloth W and the zipper F are fixed on the X-Y table 3. The 
operator selects one stitch pattern among four stitch patterns by pressing 
a pattern selection switch 111. Four patterns are provided, as shown NO. 
1-NO. 4. 
The fat line indicates rim line of the flap, so patterns NO. 1 and NO. 2 
correspond to the flap configuration shown in FIG. 4 and the flap is 
turned over to left side to be opened. In the case of NO. 2, a stitch line 
at bottom of the zipper is aslant for decorative purposes. In the case of 
stitch patterns NO. 3 and NO. 4, the flap is turned over to the right side 
to be opened. 
After selecting one of the stitch patterns from among the four stitch 
patterns, the operator sets the longitudinal and lateral dimension of the 
stitch line and a stitch pitch by pushing ten-key pad 112 and a selection 
switch 113. The lateral line stitch pattern is selected by pressing a 
lateral stitch selection switch 117. 
There are three lateral stitch patterns namely "without lateral stitch", 
"with lateral stitch", and "lateral stitch with bar tack" as shown in FIG. 
3. Back tacking may be selected at the start or end of a stitch, so there 
are several patterns and these patterns are each given pattern numbers. 
The selected pattern number is displayed at a pattern number indicator 
114. The stitch line dimensions are displayed at a data indicator 115. The 
above selected and set data are stored in the RAM 10. Then the operator 
pushes a start button 116. The CPU 8 commands stitching in response to 
data stored in the RAM and following the program stored in the ROM 9. 
The stitch pattern number will be selected such that the stitching for the 
flap Wf shall be stitched by forward feeding and the perfect stitch will 
appear on the garment. If the stitch pattern NO. 1 was previously 
selected, the CPU 8, storing the input data, drives the X-motor 12a and 
moves the X-Y table 3 such that the stitch-start point is positioned just 
under the needle. Then, the CPU 8 drives the Y-motor 12b such that the X-Y 
table 3 is moved in the direction of arrow "Y" in FIG. 4A and 
simultaneously drives the main motor 13 such that the zipper tape FT.sub.1 
is sewed to the flap portion Wf. When the stitch line reaches to the 
bottom FT.sub.12, the CPU 8 stops the Y-motor 12b and drives the X-motor 
12a and stitches the preset dimension such that the bottom portion of the 
flap Wf is stitched Thus, the first step is finished and stitch line 
S.sub.1 S.sub.2 is a perfect stitch. 
After finishing the first step, the flap Wf is turned over manually or 
mechanically. Then the start switch 116 is pressed again, and the main 
motor 13 and the X-Y driver 4 operate. The CPU 8 drives Y-motor 12b such 
that the X-Y table is reverse fed. By this reverse feed, the zipper tape 
FT.sub.2 is sewed to the flap-covered portion Wa, starting from S.sub.2e 
till the end of the front cloth W.sub.2. When the stitching reaches the 
end, the main motor 13 and the Y-motor 12b stop, and thus the second step 
is finished. In this second step, the reverse feeding forms the hitch 
stitch Sh, but this hitch stitch is covered by the flap Wf and does not 
appear on the garment so its commercial value will not be lowered. 
The aformentioned embodiment is conducted by an automatic sewing machine 
which moves the front cloth and the zipper in the X-Y direction, but it is 
also possible to use a simple sewing machine with manual work. Even in 
such a case, the rotation of the workpiece will be eliminated so the 
productivity is higher than normal. In the aforementioned embodiment, the 
stitch line at the bottom FT.sub.12 is in direction of X, but an aslant 
stitch line is also applicable as shown as patterns NO. 2 and NO. 4 in 
FIG. 3. 
As many apparently widely different embodiments of the invention may be 
made without departing the spirit and scope thereof, it is to be 
understood that invention is not limited to the specific embodiment 
thereof except as defined in the appended claims.