U.S. patent application number 11/911774 was filed with the patent office on 2009-02-12 for chain-stitch sewing machine.
This patent application is currently assigned to TOKAI KOGYO MISHIN KABUSHIKI KAISHA. Invention is credited to Sei Kato, Satoru Suzuki, Ikuo Tajima.
Application Number | 20090038519 11/911774 |
Document ID | / |
Family ID | 37115175 |
Filed Date | 2009-02-12 |
United States Patent
Application |
20090038519 |
Kind Code |
A1 |
Tajima; Ikuo ; et
al. |
February 12, 2009 |
CHAIN-STITCH SEWING MACHINE
Abstract
Chain-stitch sewing machine includes: a looper provided under a
needle plate and having a thread lead-in port and thread lead-out
port, the looper being rotationally driven in synchronism with a
sewing operation; a plurality of thread feed ports connecting to
different thread supply sources; and a connecting member having a
thread passage, the connecting member selectively connecting any
one of the plurality of thread feed ports to the thread insertion
port of the looper via the thread passage. Threading mechanism
passes the sewing thread, fed via the thread feed port connected by
the connecting member to the thread insertion port of the looper,
into the thread insertion port and causes the sewing thread to be
taken out via the inserted thread lead-out port of the looper.
Inventors: |
Tajima; Ikuo; (Nagoya-shi,
JP) ; Suzuki; Satoru; (Komaki-shi, JP) ; Kato;
Sei; (Nagoya-shi, JP) |
Correspondence
Address: |
ROSSI, KIMMS & McDOWELL LLP.
20609 Gordon Park Square, Suite 150
Ashburn
VA
20147
US
|
Assignee: |
TOKAI KOGYO MISHIN KABUSHIKI
KAISHA
Kasugai-shi
JP
|
Family ID: |
37115175 |
Appl. No.: |
11/911774 |
Filed: |
April 18, 2006 |
PCT Filed: |
April 18, 2006 |
PCT NO: |
PCT/JP2006/308148 |
371 Date: |
October 17, 2007 |
Current U.S.
Class: |
112/199 |
Current CPC
Class: |
D05B 63/00 20130101;
D05D 2207/04 20130101; D05B 85/006 20130101; D05B 1/06 20130101;
D05C 11/16 20130101; D05D 2203/00 20130101 |
Class at
Publication: |
112/199 |
International
Class: |
D05B 1/10 20060101
D05B001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2005 |
JP |
2005-119736 |
Claims
1. A chain-stitch sewing machine comprising: a
reciprocatively-driven hook needle; a looper disposed under a
needle plate and having a thread lead-in port and thread lead-out
port, said looper being rotationally driven in synchronism with a
sewing operation; a plurality of thread feed ports connecting to
different thread supply sources: a connecting member having a
thread passage, said connecting member selectively connecting any
one of said plurality of thread feed ports to the thread insertion
port of said looper via the thread passage; and a threading
mechanism for passing the sewing thread, fed via the thread feed
port connected via said connecting member to the thread insertion
port of said looper, into the thread insertion port and causing the
inserted sewing thread to be taken out via the thread lead-out port
of said looper.
2. A chain-stitch sewing machine as claimed in claim 1 wherein said
connecting member is selectively movable to align an inlet of the
thread passage with any one of said plurality of thread feed
ports.
3. A chain-stitch sewing machine as claimed in claim 1 wherein said
plurality of thread feed ports are arranged in a circular
configuration, and any one of said plurality of thread feed ports
is aligned with the inlet of the thread passage by pivoting
movement of said connecting member along the circular
configuration.
4. A chain-stitch sewing machine as claimed in claim 1 wherein said
plurality of thread feed ports are arranged in a linear
configuration, and any one of said plurality of thread feed ports
is aligned with the inlet of the thread passage by movement of said
connecting member along the linear configuration.
5. A chain-stitch sewing machine as claimed in claim 1 wherein said
threading mechanism pushes the sewing thread out to the thread
lead-out port by an air jet force.
6. A chain-stitch sewing machine as claimed in claim 1 wherein said
plurality of thread feed ports are provided in a bracket, and which
further comprises thread guide means extending from the thread
supply sources, corresponding to the thread feed ports, to the
bracket.
7. A chain-stitch sewing machine as claimed in claim 6 wherein said
plurality of thread feed ports are densely arranged in the
bracket.
8. A chain-stitch sewing machine as claimed in claim 1 wherein said
looper is positioned inside a sewing workpiece.
9. A chain-stitch sewing machine comprising: a
reciprocatively-driven hook needle; a looper disposed under a
needle plate and having a thread lead-in port and thread lead-out
port, said looper being rotationally driven in synchronism with a
sewing operation; a plurality of thread feed ports arranged in a
circular configuration; a selection device for selectively
connecting any one of said plurality of thread feed ports to the
thread insertion port of said looper; and a threading mechanism for
passing a sewing thread, fed via the thread feed port connected via
said selection device to the thread insertion port of said looper,
into the thread insertion port and causing the inserted sewing
thread to be taken out via the thread lead-out port of said looper,
wherein the sewing thread taken out via the thread lead-out port is
rotated in response to rotation of said looper so that chain-stitch
sewing is performed through cooperation between said looper and
said hook needle.
Description
[0001] This application is a U.S. National Phase Application of PCT
International Application PCT/JP2006/308148 filed on Apr. 18,
2006.
TECHNICAL FIELD
[0002] The present invention relates to a chain-stitch sewing
machine capable of multi-color, chain-stitch sewing by a single
looper selectively using a plurality of sewing threads of different
colors and characteristics. More particularly, the present
invention relates to a chain-stitch sewing machine suited to
perform chain-stitch sewing on a cylindrical sewing workpiece.
BACKGROUND ART
[0003] Chain-stitch sewing machines have been known, in which
chain-stitch sewing is performed on a sewing workpiece by
cooperation between a reciprocatively-driven hook needle and a
looper positioned under a needle plate to feed a sewing thread and
by rotation of the looper being controlled in synchronism with
sewing operation of the hook needle. Also known today are
chain-stitch sewing machines of a type which has a single looper
per machine head (also called "sewing head") and in which a
plurality of sewing threads of different colors and characteristics
are prepared for the single looper; in these chain-stitch sewing
machines, chain-stitch sewing with multiple color threads (i.e.,
multi-color chain-stitch sewing) is performed on a sewing workpiece
by selectively inserting any one of the sewing threads through the
looper. One example of such chain-stitch sewing machines, capable
of multi-color chain-stitch sewing by a single looper selectively
using a plurality of sewing threads, is disclosed in Japanese
Patent No. 3457040 (hereinafter "Patent Literature 1") or Japanese
Patent Application Laid-open Publication No. 2002-317374
(hereinafter "Patent Literature 2"). In the conventional
chain-stitch sewing machine disclosed in Patent Literature 1 or
Patent Literature 2, a thread feed mechanism slidable in a
horizontal direction is disposed under the looper for selectively
supplying any one of a plurality of sewing threads. The plurality
of sewing threads are set on the thread feed mechanism in parallel
with one another along a sliding direction of the thread feed
mechanism. Sewing thread color change (i.e., color thread
selection) is effected by sliding the array of the plurality of
sewing threads, by means of the thread feed mechanism, so that any
desired one of the threads is positioned directly beneath the
looper and then passing the sewing thread, positioned directly
beneath the looper, through the looper by injection of air.
[0004] As noted above, the conventional chain-stitch sewing
machines are constructed to effect a sewing thread color change by
sliding the array of the plurality of sewing threads by means of
the thread feed mechanism that has the plurality of sewing threads
set thereon in parallel with one another. Thus, it is difficult to
reduce the size of the machines, and there is a need to secure a
sliding space (i.e., leeway space for horizontal movement) of a
width that is about twice as great as the horizontal width of the
array of the plurality of sewing threads. Therefore, the
conventional chain-stitch sewing machines of the type, capable of
effecting color thread selection, can be applied only to
planar-shaped sewing workpieces, although sewing workpieces to be
processed by the sewing machines also include cylindrically-shaped
sewing workpieces, such as T-shirts and hats. As well known, in
order to perform ordinary sewing or embroidering on a
cylindrically-shaped sewing workpiece, it is necessary to position
a cylindrical rotary hook bead, having a rotary bed provided
therein, inside the cylindrically-shaped sewing workpiece.
Similarly, in order to perform chain-stitch sewing on a
cylindrically-shaped sewing workpiece, it is necessary to position
a looper inside the cylindrically-shaped sewing workpiece. However,
in the conventional chain-stitch sewing machines, which are capable
of effecting a sewing thread color change by passing a desired one
of the plurality of loopers through the single looper, it is
difficult to reduce the size of the machines and necessary to
secure a wide sliding space (leeway space for horizontal movement)
because the array of the plurality of sewing threads itself is slid
horizontally along the sliding direction of the thread feed
mechanism. Therefore, cylindrically-shaped sewing workpieces, on
which the conventional chain-stitch sewing machines can perform
chain-stitch sewing, are limited to those of relatively great
sizes, but also, even for cylindrically-shaped sewing workpieces of
great sizes on which the conventional chain-stitch sewing machines
can perform chain-stitch sewing, sewable ranges of the workpieces
would be extremely limited; consequently, the conventional
chain-stitch sewing machines would lack practical utility. Thus, in
effect, there has heretofore been no chain-stitch sewing machine
suitable for performing multi-color chain-stitch sewing on
cylindrically-shaped sewing workpieces.
DISCLOSURE OF THE INVENTION
[0005] In view of the foregoing, it is an object of the present
invention to provide a chain-stitch sewing machine, of a type
having one looper per machine head, which has a compact thread feed
mechanism for selectively feeding a desired one of a plurality of
sewing threads to the looper to permit sewing with the desired
thread. It is another object of the present invention to provide a
chain-stitch sewing machine suited for performing chain-stitch
sewing on a cylindrically-shaped sewing workpiece using threads of
multiple colors.
[0006] According to a first aspect of the present invention, there
is provided a chain-stitch sewing machine, which comprises: a
reciprocatively-driven hook needle; a looper disposed under a
needle plate and having a thread lead-in port and thread lead-out
port, the looper being rotationally driven in synchronism with a
sewing operation; a plurality of thread feed ports connecting to
different thread supply sources: a connecting member having a
thread passage, the connecting member selectively connecting any
one of the plurality of thread feed ports to the thread insertion
port of the looper via the thread passage; and a threading
mechanism for passing the sewing thread, fed via the thread feed
port connected via the connecting member to the thread insertion
port of the looper, into the thread insertion port and causing the
inserted sewing thread to be taken out via the thread lead-out port
of the looper.
[0007] According to the first aspect of the present invention, the
provision, between the plurality of thread feed ports and the
looper, of the connecting member that selectively connects any one
of the plurality of thread feed ports to the thread insertion port
of the looper via the thread passage can make compact mechanisms
for selecting and feeding a thread to the looper. As a consequence,
the looper and all of such mechanisms for selectively feeding any
one of threads, having different colors and characteristics, to the
single looper can be accommodated compactly within a looper base
having a cantilevered shape with its one end portion projecting
outwardly. Thus, a cylindrically-shaped sewing workpiece can be
taken in and out via the one end portion of the looper base, and
therefore, there can be provided a chain-stitch sewing machine
suited for chain-stitch sewing on cylindrically-shaped sewing
workpieces. Further, the construction of the mechanisms for
selecting and feeding a thread to the looper can be made compact as
compared to the conventional counterparts, and thus, the present
invention can advantageously be applied to a sewing machine which
performs chain-stitch sewing on planar-shaped sewing workpieces as
well as cylindrically-shaped sewing workpieces.
[0008] In a preferred embodiment, the connecting member, provided
between the plurality of thread feed ports and the looper, is
selectively movable to align the inlet of the thread passage with
any one of said plurality of thread feed ports. With such a
construction that the connecting member is moved without the
arrangement or array of the plurality of thread feed ports being
moved, it is possible to simplify the construction of the slide
mechanism and reduce the size of a movement mechanism; besides, it
is possible to eliminate a need for an extra space to secure a
movable (e.g., slidable) range of the movement mechanism (because
the plurality of thread feed ports themselves are not moved
horizontally).
[0009] In another preferred embodiment, the plurality of thread
feed ports are arranged in a circular configuration, and any one of
the plurality of thread feed ports is aligned with the inlet of the
thread passage by pivoting movement of the connecting member along
the circular configuration. Thus, the mechanism for feeding a
sewing thread to the thread insertion port of the looper can be
reduced in size. Further, because color thread selection can be
effected by the connecting member being moved along the circular
configuration instead of being slid horizontally, it is possible to
eliminate a need for an extra space to secure a movable (e.g.,
slidable) range of the movement mechanism. As a result, the present
invention can be applied even more advantageously to a sewing
machine which performs chain-stitch sewing on cylindrically-shaped
sewing workpieces.
[0010] According to another aspect of the present invention, there
is provided a chain-stitch sewing machine, which comprises: a
reciprocatively-driven hook needle; a looper disposed under a
needle plate and having a thread lead-in port and thread lead-out
port, the looper being rotationally driven in synchronism with a
sewing operation; a plurality of thread feed ports arranged in a
circular configuration; a selection device for selectively
connecting any one of the plurality of thread feed ports to the
thread insertion port of the looper; and a threading mechanism for
passing a sewing thread, fed via the thread feed port connected via
the selection device to the thread insertion port of the looper,
into the thread insertion port and causing the inserted sewing
thread to be taken out via the thread lead-out port of the looper.
Here, the sewing thread taken out via the thread lead-out port is
rotated in response to rotation of the looper so that chain-stitch
sewing is performed through cooperation between the looper and the
hook needle. Because the plurality of thread feed ports are
arranged in a circular configuration, even where the arrangement or
array of the thread feed ports is to be moved for color thread
selection, the array of the thread feed ports can be moved along
the circular configuration instead of being slid horizontally, and
thus, it is possible to eliminate a need for an extra space to
secure a movable (e.g., slidable) range. As a result, the present
invention can be applied even more advantageously to a sewing
machine which performs chain-stitch sewing on cylindrically-shaped
sewing workpieces.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a view showing an outer appearance of a multi-head
type chain-stitch sewing machine in accordance with an embodiment
of the present invention;
[0012] FIG. 2 is a side view of a looper base taken from a right
side of the sewing machine of FIG. 1 as the machine is viewed from
its front;
[0013] FIG. 3 is a sectional side view of the looper base;
[0014] FIG. 4 is a top plan view of the looper base;
[0015] FIG. 5 is a bottom plan view of the looper base;
[0016] FIG. 6 is a front view of the looper base taken from the
front of the sewing machine of FIG. 1;
[0017] FIG. 7 is a sectional side view, similar to FIG. 3, showing
in enlarged scale a distal end portion of the looper base shown in
FIG. 3;
[0018] FIG. 8 is a perspective view showing, in enlarged scale, a
part of an internal construction of the distal end portion of the
looper base in the embodiment; and
[0019] FIG. 9 is a sectional plan view of an air supply block.
BEST MODE FOR CARRYING OUT THE INVENTION
[0020] Embodiments of the present invention will be described in
detail with reference to the accompanying drawings.
[0021] FIG. 1 is a view showing an outer appearance of a multi-head
type chain-stitch sewing machine in accordance with an embodiment
of the present invention, which is equipped with a plurality of
chain-stitch sewing machine heads 3. Reference numeral 1 represents
a machine frame, and 2 represents a table that has an
ascendable/descendable front table section 2a. On the front surface
of the machine frame 1, there are provided the plurality of (four
in the illustrated example) chain-stitch sewing machine heads 3
whose construction is well known per se. Each of the chain-stitch
sewing machine heads 3 has a hook needle 4 (see FIG. 7)
reciprocatively driven in a vertical direction. Cylindrical looper
base (looper section) 5 is disposed under each of the machine heads
3. Base frame (not shown) movable in X and Y directions is disposed
on the table 2, and a pair of left and right support arms 6 are
provided on the not-shown base frame per machine head 3. Sewing
frame 7 having set thereon a cylindrically-shaped sewing workpiece
H, such as a body part of a T-shirt, is supported by the pair of
left and right support arms 6. The looper base 5 has a shape such
that its front distal end portion protrudes into a space, e.g. a
cylindrical or rod-like shape, so that it can enter inside a
cylindrically-shaped sewing workpiece H set on the sewing frame 7,
and it is in the form of a cantilevered support structure having
its proximal end portion (i.e., rear end portion) fixed to the
machine frame 1.
[0022] Internal construction of the looper base 5 will be described
in detail. FIG. 2 is a side view of the looper base 5, employed in
the instant embodiment, taken from a right side of the sewing
machine of FIG. 1 as the machine is viewed from its front, and FIG.
3 is a sectional side view of the looper base 5. In FIGS. 2 and 3,
the front distal end portion of the looper base 5 protruding into
the space is shown in a left end area of the figures, while the
proximal end portion (rear end portion) of the looper base 5 fixed
to the machine frame 1 is shown in a right end area of the figures.
FIG. 4 is a top plan view of the looper base 5, and FIG. 5 is a
bottom plan view of the looper base 5. Further, FIG. 6 is a front
view of the looper base 5 taken from the front of the sewing
machine of FIG. 1. As clearly seen in FIGS. 2 and 5, a base body
member 8 of the looper base 5 is fixed to the machine frame 1 by
means of four stud bolts 9. A plurality of covers are provided
above and beneath the base body member 8, and the whole of the
looper base 5 is covered with these covers. To facilitate
understanding, FIGS. 2, 4, 5 and 6 show the looper base 5 with the
covers removed (in the figures, the covers are indicated by
imaginary lines).
[0023] As shown primarily in FIGS. 2, 3, 4, 5, etc., a looper R is
provided in a distal end portion (left end portion in FIGS. 2 and
3, or lower end portion in FIGS. 4 and 5) of the base body member
8, and the looper R is rotatably supported by the base body member
8 and a support member 10 fixed beneath the base body member 8 with
a predetermined spacing formed between the members 8 and 10. Pulley
section Ra is formed on the outer periphery of the looper R. Motor
14 is fixedly provided on a proximal end portion (right end portion
in FIGS. 2 and 3, or upper end portion in FIGS. 4 and 5) of the
base body member 8, and a driving pulley 15 is fixedly provided on
the shaft of the motor 14. Further, a bearing member 13 is provided
between the distal end portion and proximal end portion of the base
body member 8 and forwardly of a middle point between the distal
and proximal end portions. The bearing member 13 rotatably supports
an intermediate pulley section 12 having a large-diameter pulley
12a and small-diameter pulley 12b vertically spaced from each other
with the base body member 8 held therebetween. Timing belt 16 is
wound at its opposite end on the pulley section Ra of the looper R
and the large-diameter pulley 12a of the intermediate pulley
section 12, while a timing belt 17 is wound at its opposite end on
the small-diameter pulley 12b of the intermediate pulley section 12
and the driving pulley 15 of the motor 14. With such arrangements,
as the driving pulley 15 rotates by being driven by the motor 14,
the rotation of the driving pulley 15 is transmitted to the
small-diameter pulley 12b via the timing belt 17, so that the
large-diameter pulley 12a fixed to the same shaft as the
small-diameter pulley 12b is rotated. Further, as the
large-diameter pulley 12a rotates, the rotation of the
large-diameter pulley 12a is transmitted via the timing belt 16 to
the pulley section Ra. In this way, the looper R can be ultimately
rotationally driven by the rotational force transmitted from the
motor 14.
[0024] FIG. 7 is a sectional side view showing in enlarged scale
the distal end portion of the looper base 5 shown in FIG. 3, and
FIG. 8 is a perspective view showing, in enlarged scale, a part of
the internal construction of the distal end portion of the looper
base 5. As clearly seen from FIG. 7, the looper R has a
thread-passing hole 11 formed vertically therethrough to allow a
sewing thread T to pass through the hole 11. The thread-passing
hole 11 is shaped to have a curved intermediate portion as shown,
and it is formed in such a manner that the sewing thread T,
inserted through a lower-end thread-inserting opening or thread
insertion port 11a, can be led out through an upper-end opening Rb.
Namely, the thread-passing hole 11 has the lower-end thread
insertion port 11a formed in a position coinciding with the
rotation center of the looper R, the upper-end opening Rb formed in
a position offset from the rotation center of the looper R, and the
curved intermediate portion. Thread lead-out tube 45 is vertically
provided in the upper-end opening Rb, and the upper end of the
thread lead-out tube 45 is formed as a thread lead-out opening or
port 11b. The thread lead-out port 11b leads the sewing thread T
out of the hole 11 toward a needle hole 43a that is formed in a
needle plate 43 fixed to a bracket 34 and that permits passage
therethrough of the hook needle 4. As well known in the art, the
sewing thread T led out through the thread lead-out port 11b is
wound around the hook needle 4 by the looper R being rotationally
driven as noted above with the hook needle 4 lowered so that a hook
portion at the distal end of the hook needle 4 passes through the
needle hole 43a, and then, chain-stitch sewing is performed by the
hook needle 4 being raised so that the hook portion hooks the wound
sewing thread T to pull the thread T over the surface of a sewing
workpiece. Sewing threads T are paid out from a plurality of thread
spools positioned on a thread stand, and any one of the sewing
threads T paid out from the plurality of thread spools is
selectively supplied to the thread-passing hole 11 (as will be
later detailed).
[0025] As shown in FIGS. 3, 5, etc., a shaft 18 is rotatably
supported via a bearing 19 fixed to the underside of the base body
member 8 and a bracket 20 fixed to the underside of the support
member 10. Driven gear 21 is fixed to a rear end portion of the
shaft 18 and held in meshing engagement with a driving gear 22
located beneath the driven gear 21. The driving gear 22 is fixed to
a slide shaft 23 driven to slide in the left-right horizontal
direction in response to an instruction given to the chain-stitch
sewing machine for changing the sewing thread T to be used. The
driving gear 22 and driven gear 21 are each in the form of a spiral
gear. Therefore, the shaft 18 is driven to pivot, via the driving
gear 22 and driven gear 21, as the slide shaft 23 is driven to
slide. As shown in FIGS. 5, 6, 8 etc., a plurality of (nine in the
illustrated example) guide tubes 24 are disposed along an imaginary
circle about the axis of the shaft 18. In each of the guide tubes
24, one of the sewing threads T paid out from the plurality of
thread spools positioned on the thread stand (not shown) can be set
by being passed from a rear end portion toward a front end portion
of the guide tube 24. Each of the guide tubes 24 has a distal end
portion supported by the bracket 20; the bracket 20 has, in
corresponding relation to the guide tubes 24, a plurality of thread
feed ports that function as exits for the sewing threads T set in
the corresponding guide tubes 24. Each of the guide tubes 24 has a
rear portion, which is bent so that its rear end is oriented
substantially vertically downward. The guide tubes 24 have their
respective rear ends to a guide member 26 in a left-right
horizontal row, and the guide member 26 is fixed to the machine
frame 1; in this way, the sewing threads T paid out from the
plurality of thread spools positioned on the not-shown thread stand
(thread supply source) disposed in a predetermined area below the
guide member 26 are pulled into the respective guide tubes 24.
Further, portions located forwardly of the rear bent portions of
the guide tubes 24 are supported by a support member 25. With such
structural arrangements, the plurality of thread feed ports can be
provided in the bracket 20 densely or close to one another (i.e.,
at intervals smaller than installation intervals of the thread
stands), and thus, the thread feed ports can be packed compactly;
in addition, the looper base 5 can be suitably positioned inside a
cylindrically-shaped sewing workpiece H.
[0026] Connecting member 27 is fixed to the distal end of the shaft
18 rotatably supported on the underside of the base body member 8
as noted above. As clearly seen in FIGS. 7 and 8, the connecting
member 27 has a single slanted, communicating hole (thread passage)
27a, and a communicating portion 27b is provided at the distal or
front end of the hole 27a. The communicating hole (thread passage)
27a extends obliquely with its distal end (left end in FIG. 7)
located on an extension of the axis of the shaft 18 and its rear
end (right end in FIG. 7) capable of being positioned to align with
the distal end of any one of the guide tubes 24 (more specifically,
any one of the thread feed ports of the bracket 20). Thus, the
connecting member 27 is caused to pivot, a predetermined angle
(pitch) at a time, as the above-mentioned shaft 18 pivots, in
response to which the communicating hole (thread passage) 27a can
selectively communicate, one after another, with the individual
guide tubes 24 having their distal end portions supported by the
bracket 20 so that one thread passage, through which the sewing
thread T passes therethrough, can be defined in conjunction with
any one of the guide tubes 24.
[0027] Air supply block 28 is secured to the underside of the
support member 10. As apparent from FIGS. 7 and 8, a nozzle 29 is
fixed to the air supply block 28, and the air supply block 28 and
connecting member 27 are positioned relative to each other in such
a manner that the communicating portion 27b of the connecting
member 27 gets into a rear end portion of the nozzle 29. Connecting
tube 30 is fixed to the distal end of the nozzle 29 and has its
raised upper end tightly abuts against the thread insertion port
11a of the looper R. FIG. 9 is a sectional plan view of the air
supply block 28. Connector 31 is fixed to the air supply block 28,
and a tube 32 extending from an air supply source (not shown) is
connected to the connector 31. Thus, air is supplied from the air
supply source into the air supply block 28. Once air is supplied to
the air supply block 28, the air flows, via an air passage 28a,
into an annular space 28b formed between a nipple portion 29a of
the nozzle 29 and the air supply block 28 and is swiftly introduced
from the outer periphery of the nipple portion 29a into the
connecting tube 30 and then blown out of the thread lead-out port
11b of the thread-passing hole 11. As a consequence, a negative
pressure is produced in the nipple portion 29a so that a
thread-sucking force is produced. Namely, as air is supplied from
the air supply source after the shaft 18 is caused to pivot and the
communicating hole 27a of the connecting member 27 connects or
communicates with the guide tube 24 having a desired sewing thread
T passed therethrough, the desired sewing thread T can be passed
through the thread-passing hole 11. In this way, a series of feed
passages for the sewing thread T can be formed which extends from
the thread stand, through the guide tube 24 (thread feed port of
the bracket 20) and communicating hole 27a of the connecting member
27, to the thread-passing hole 11 of the looper R. With such an air
supply block 28, air supply source, connecting tube 30, etc., a
threading mechanism is defined which functions to pass a thread
through the thread insertion port 11a of the looper R into the
thread-passing hole 11.
[0028] As shown in FIG. 4, a movable cutter blade 33 is pivotably
supported on the bracket 34 fixed to the upper surface of the base
member 8. The movable cutter blade 33 has a connecting arm 33a that
is connected via a connecting plate 35 to a lever 36. The lever 36
is fixed to the upper end of a shaft 37 pivotally supported on the
base member 8, and a drive arm 38 is fixed to the lower end of the
shaft 37 as shown in FIG. 5. The drive arm 38 is connected at its
distal end with a fixation block 40 via a connecting rod 39. The
fixation block 40 is fixed to a slide shaft 41 that is driven to
slide in the left-right horizontal direction in response to a
thread-cutting instruction given to the instant chain-stitch sewing
machine. Thus, the movable cutter blade 33 is caused to pivot as
the slide shaft 41 is driven to slide. Further, a fixed cutter
blade 42 is fixed to a side surface of the bracket 34, and the
sewing thread T is cut by cooperation between the fixed cutter
blade 42 and the movable cutter blade 33. Namely, during a sewing
operation, the movable cutter blade 33 is held in a pivotal
position indicated by a solid line in FIG. 4, i.e. in a position
where it does not have any influence on the sewing thread T lead
out from the looper R. In cutting the sewing thread T, the movable
cutter blade 33 is caused to first pivot in the clockwise direction
of FIG. 4 to a position such that the sewing thread T can be
captured by the fixed cutter blade 42 and then pivot in the
counterclockwise direction back to the solid-line pivotal position
of FIG. 4 with the sewing thread T captured thereby. During that
time, the movable cutter blade 33 and fixed cutter blade 42 engage
with each other to cut the sewing thread T. At that time, the
looper-side thread end portion of the thus-cut sewing thread T is
retained by a not-shown retaining member; such retention of the
looper-side thread end portion of the cut sewing thread T will be
canceled as the movable cutter blade 33 is caused to pivot a
predetermined amount in the clockwise direction.
[0029] Beneath the rear ends of the guide tubes 24, a
thread-pulling device is provided for pulling the thread end
portion of the sewing thread T, having so far been inserted in the
looper R (i.e., having so far been involved in a sewing operation),
so that the thread end portion is positioned within the guide tube
24. As such a thread-pulling device, there may be employed a
pulling-down member, increase means for increasing a pulled-down
amount of a thread, etc. as disclosed in the above-discussed No.
2002-317374 publication of the application assigned to the same
assignee as the instant application. Because the pulling-down
member, increase means, etc. are known, they will not be described
here. Of course, the present invention is not limited to the
aforementioned.
[0030] The following lines describe behavior of the chain-stitch
sewing machine of the present invention, constructed in the
aforementioned manner, when performing chain-stitch sewing on a
cylindrically-shaped sewing workpiece. Sewing threads T of
different colors and characteristics, paid out from the plurality
of thread spools positioned on the not-shown thread stand are set
in advance in the individual guide tubes 24. To start the
chain-stitch sewing, first the shaft 18 is caused to pivot so that
the communicating hole 27a of the connecting member 27 is connected
with, i.e., brought into communication with, any one of the guide
tubes 24 which has a desired sewing thread T set therein. Once air
is supplied from the air supply source to the air supply block 28,
the desired sewing thread T set in the one guide tube 24 is
inserted, by the supplied air, into the thread-passing hole 11 of
the looper R and led out through the thread lead-out port 11b.
Then, the movable cutter blade 33 is caused to pivot, just as in
cutting of the thread, so as to retain an end portion of the sewing
thread T led out through the thread lead-out port 11b by way of the
communicating hole 27a of the connecting member 27, connecting tube
30 of the air supply block 28 and thread-passing hole 11 of the
looper R.
[0031] Once the end portion of the sewing thread T is retained in
the aforementioned manner, not only the motor 14 is activated to
rotate the looper R but also the hook needle 4 of the machine head
3 is moved up and down, in synchronism with which the embroider
frame 7 having a cylindrically-shaped sewing workpiece H set
thereon is moved in the X/Y direction. In this manner, chain-stitch
sewing of a pattern, embroidery and/or the like is performed on the
sewing workpiece H.
[0032] When the sewing thread T used for the chain-stitch sewing is
to be changed to another one, the rotation of the looper R and
up-and-down movement of the hook needle 4 is halted, and then the
movable cutter blade 33 is caused to pivot first in the clockwise
direction and then in the counterclockwise direction to cut the
sewing thread T. After cutting of the sewing thread T, the movable
cutter blade 33 is caused to pivot a predetermined amount in the
clockwise direction to cancel the retention of the looper-side end
portion of the sewing thread T. After that, the sewing thread T
inserted through the looper R is pulled by the not-shown thread
pulling device to position the looper-side end portion of the
sewing thread T, having been released from the retention, within
the guide tube 24. Then, the shaft 18 is caused to pivot so that
the communicating hole 27a of the connecting member 27, is
connected with, i.e. brought into communication with, another one
of the guide tubes 24 which has a next, desired sewing thread T set
therein, air is supplied to the air supply block 28 to cause the
sewing thread T to be passed through the looper R, and then the
movable cutter blade 33 is caused to pivot so as to retain an end
portion of the sewing thread T inserted through the looper R. Then,
in a similar manner to the above-described, not only the looper R
is rotated but also the hook needle 4 is moved up and down so that
chain-stitch sewing with the desired sewing thread T is performed
on the sewing workpiece H. As known in the art, examples of the
chain-stitch sewing include chain sewing, loop sewing, etc., and
switching can be made among these chain sewing, loop sewing, etc.
in response to setting of a desired sewing operation.
[0033] As set forth above, the embodiment of the chain-stitch
sewing machine of the present invention is constructed to guide a
plurality of threads to the neighborhood of the looper R by means
of the guide tubes 24 and allow any one of the guide tubes 24 and
the thread-passing hole 11 of the looper R to communicate with each
other. Thus, the embodiment of the chain-stitch sewing machine can
significantly reduce the sizes of component parts located beneath
the looper R and thereby construct the looper base 5 into a
cylindrical shape of a reduced width. In this way, the looper base
5 can be positioned inside any one of a variety of
cylindrically-shaped sewing workpieces H. Further, because it is
only necessary to rotate the small-size connecting member 27 when
the sewing thread T is to be switched to another, not only the
drive source can be reduced in size, but also desired thread color
change can be effected at high speed.
[0034] The embodiment has been described above in relation to the
case where air from the air supply source is supplied only to the
air supply block 28 so that a sewing thread T set in the guide tube
24, brought into communication with the thread-passing hole 11 of
the looper R, can be inserted through the thread-passing hole 11;
however, the present invention is not so limited, and air may also
be supplied to the neighborhood of the rear end portion of the
guide tube 24 so as to assist movement of the sewing thread T in
the guide tube 24.
[0035] Note that the aforementioned structure for guiding sewing
threads T to the neighborhood of the looper R and allowing any
desired one of the sewing threads to be inserted through the single
looper R by selectively connecting or communicating the thread
insertion port 11a of the looper R with the end of the guide tube
24 via the connecting member 27 need not necessarily be capable of
being positioned inside a cylindrically-shaped sewing workpiece H.
Namely, the present invention may also be applied to sewing
machines which perform chain-stitch sewing on planar-shaped sewing
workpieces.
[0036] Further, the guide tubes 24 for guiding sewing threads T to
the neighborhood of the looper R and the thread feed ports of the
bracket 20 may be arranged, for example, in a linear horizontal
configuration or array, rather than in a circular configuration or
array about the axis of the shaft 18. Of course, in such a case,
the connecting member 27 is driven to linearly move, instead of
being driven to rotate, so that the communicating hole 27a
communicates with any one of the guide tubes 24. In such a case
too, the present invention can significantly simplify the
construction of the slide mechanism and reduce the size of the
slide mechanism by moving the connecting member 27 without moving
the array of the plurality of thread feed ports; besides, the
present invention can eliminate a need for an extra space in order
to secure a slidable range of the slide mechanism.
[0037] Further, as a modification of the present invention, there
may be provided opening/closing-controllable shutters in
corresponding relation to the individual thread feed ports of the
bracket 20, in both of the cases where the plurality of thread feed
ports are arranged in a circular configuration and where the
plurality of thread feed ports are arranged in a horizontal
configuration; in this case, the connecting member 27 may have a
plurality of thread passages provided at its inlet in corresponding
relation to the individual thread feed ports, and the plurality of
thread passages may be connected to one passage at the outlet of
the connecting member 27. With such modified arrangements, the
present invention permits color thread selection by opening only
the shutter corresponding to a desired color thread without moving
the connecting member 27. The shutters corresponding to the thread
feed ports may be provided either on the bracket 20 or on the
connecting member 27.
[0038] As another modification of the present invention, the
bracket 20, having the plurality of thread feed ports arranged in a
circular configuration, may be caused to pivot along the circular
configuration. In such a case too, it is possible to eliminate a
need for an extra space to secure the slidable range of the slide
mechanism, and thus, the looper base 5 can be significantly reduced
in size as a whole so that it can be suited for being positioned
inside a cylindrically-shaped sewing workpiece set on the
embroidery frame 7.
[0039] Further, the guide tubes 24 may be of any desired shape
other than a tubular shape, as along as they can guide sewing
threads T to the bracket 20.
[0040] The embroider frame 7, which is driven in the X/Y direction
in accordance with sewing pattern data, may be rotationally driven
as known in the field of embroidery sewing on hats etc., instead of
being driven in the planar X/Y direction alone. Further, the
machine head 3 and looper base 5 may be moved in accordance with a
sewing pattern.
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