U.S. patent application number 10/579301 was filed with the patent office on 2007-03-15 for bobbin changer apparatus for sewing machine.
This patent application is currently assigned to Tokai Kogyo Mishin Kabushiki Kaisha. Invention is credited to Taichi Fukushima, Haruhiko Kinoshita, Ikuo Tajima.
Application Number | 20070056490 10/579301 |
Document ID | / |
Family ID | 34587071 |
Filed Date | 2007-03-15 |
United States Patent
Application |
20070056490 |
Kind Code |
A1 |
Tajima; Ikuo ; et
al. |
March 15, 2007 |
Bobbin changer apparatus for sewing machine
Abstract
Transfer mechanism (20) is provided for reciprocally
transferring a bobbin grasping device (10), grasping a bobbin case
(B) at the distal end of a chuck section (11), between a rotary
hook (6) of a sewing machine and a bobbin stock section (8). First
cam plate (31) is provided adjacent to one end for orienting the
chuck section (11) toward the rotary hook (6) during the transfer,
while a second cam plate (41) is provided adjacent to the other end
for orienting the chuck section (11) toward the bobbin stock
section (8) during the transfer. The cam plates (31, 41) are
detachable from the transfer mechanism (20), and, in transportation
of the machine, one of the cam plates is transported as an
attachment to a main sewing table, while the other plate is
transported as an attachment to an extension sewing table. The
bobbin grasping device (10) includes a moving body section (13),
chuck section (11), and a spring member (19) for normally biasing
the chuck section toward a predetermined neutral position.
Inventors: |
Tajima; Ikuo; (Aichi,
JP) ; Fukushima; Taichi; (Aichi, JP) ;
Kinoshita; Haruhiko; (Aichi, JP) |
Correspondence
Address: |
ROSSI, KIMMS & McDOWELL LLP.
P.O. BOX 826
ASHBURN
VA
20146-0826
US
|
Assignee: |
Tokai Kogyo Mishin Kabushiki
Kaisha
1800, Ushiyamacho Kasugau-shi
Aichi
JP
486-0901
Kinsoshita Precision Industrial Co., Ltd.
201, Marushinicho, Kita-ku Nagoya-shi
Aichi
JP
462-0063
|
Family ID: |
34587071 |
Appl. No.: |
10/579301 |
Filed: |
November 17, 2003 |
PCT Filed: |
November 17, 2003 |
PCT NO: |
PCT/JP03/14591 |
371 Date: |
June 19, 2006 |
Current U.S.
Class: |
112/186 |
Current CPC
Class: |
D05B 59/04 20130101 |
Class at
Publication: |
112/186 |
International
Class: |
D05B 57/10 20060101
D05B057/10 |
Claims
1. A bobbin changer apparatus for replacing a lower thread bobbin
to be mounted in a rotary hook of a sewing machine, said bobbin
changer apparatus comprising: a bobbin grasping device for grasping
a bobbin case at a distal end of a chuck section; a transfer
mechanism for reciprocally transferring said bobbin grasping device
between the rotary hook of the sewing machine and a bobbin stock
section; a first orientation change mechanism for orienting the
chuck section of said bobbin grasping device toward the rotary hook
of the sewing machine during transfer, by said transfer mechanism,
of said bobbin grasping device toward the rotary hook; and a second
orientation change mechanism for orienting the chuck section of
said bobbin grasping device toward the bobbin stock section during
transfer, by said transfer mechanism, of said bobbin grasping
device toward the bobbin stock section, wherein the first and
second orientation change mechanisms are detachable from said
transfer mechanism.
2. A bobbin changer apparatus as claimed in claim 1 wherein said
transfer mechanism includes a guide section for guiding said bobbin
grasping device between the rotary hook and the bobbin stock
section, and a drive section for reciprocally transferring said
bobbin grasping device along said guide section.
3. A bobbin changer apparatus as claimed in claim 1 wherein each of
said first and second orientation change mechanisms has a slanted
cam surface, and wherein said bobbin grasping device includes a cam
follower in relation to the chuck section, and the chuck section is
caused to pivot to change an orientation of the distal end by the
cam follower moving along the cam surface.
4. A bobbin changer apparatus for replacing a lower thread bobbin
to be mounted in a rotary hook of a sewing machine, said bobbin
changer apparatus comprising: a bobbin grasping device for grasping
a bobbin case at a distal end of a chuck section; a transfer
mechanism for reciprocally transferring said bobbin grasping device
between the rotary hook of the sewing machine and a bobbin stock
section; a first orientation change mechanism for orienting the
chuck section of said bobbin grasping device toward the rotary hook
of the sewing machine during transfer, by said transfer mechanism,
of said bobbin grasping device toward the rotary hook; and a second
orientation change mechanism for orienting the chuck section of
said bobbin grasping device toward the bobbin stock section during
transfer, by said transfer mechanism, of said bobbin grasping
device toward the bobbin stock section, wherein said bobbin
grasping device includes a moving body section linearly movable by
said transfer mechanism, the chuck section pivotally supported on
said moving body section, and a spring member for normally biasing
the chuck section toward a predetermined neutral position, and said
first orientation change mechanism orients the distal end of said
chuck section toward the rotary hook against a biasing force of
said spring member, and said second orientation change mechanism
orients the distal end of said chuck section toward the bobbin
stock section against the biasing force of said spring member.
5. A bobbin changer apparatus as claimed in claim 4 wherein said
spring member is a torsion spring, and a pin pivotable in response
to pivoting movement of said chuck section is provided on said
chuck section in engagement with the torsion spring, and wherein,
as said chuck section is caused to pivot via said first and second
orientation change mechanisms, the torsion spring is displaced by
the pin, otherwise, said chuck section is returned to the neutral
position via the pin through the biasing force of the torsion
spring.
6. A bobbin changer apparatus as claimed in claim 4 wherein each of
said first and second orientation change mechanisms has a slanted
cam surface, and wherein said bobbin grasping device includes a cam
follower in relation to the chuck section, and the chuck section is
caused to pivot to change an orientation of the distal end by the
cam follower moving along the cam surface.
7. A bobbin changer apparatus for replacing a lower thread bobbin
to be mounted in a rotary hook of a sewing machine, said bobbin
changer apparatus comprising: a bobbin grasping device for grasping
a bobbin case at a distal end of a chuck section; and a transfer
mechanism for reciprocally transferring said bobbin grasping device
between the rotary hook of the sewing machine and a bobbin stock
section, said bobbin grasping device comprising: an arm-grasping
claw for pulling out a bobbin case arm; drive means for causing
said arm-grasping claw to pivot so as to pull out the bobbin case
arm; and an arm-engaging protrusion for engaging with the bobbin
case arm having been pulled out by said arm-grasping claw.
8. A bobbin changer apparatus for a multi-head sewing machine
having a plurality of machine heads, in which said bobbin changer
apparatus recited in claim 1 is provided for each of rotary hooks
that are provided in corresponding relation to the machine
heads.
9. A bobbin changer apparatus for a multi-head sewing machine as
claimed in claim 8 wherein said transfer mechanism includes a
timing belt for holding said bobbin grasping device so that the
timing belt is driven to move together with said bobbin grasping
device, and which further comprises a common drive-force
transmission mechanism for transmitting a drive force of a common
motor to said timing belt of said transfer mechanism of each of
said bobbin changer apparatus corresponding to the machine
heads.
10. A bobbin changer apparatus for a multi-head sewing machine as
claimed in claim 8 wherein the multi-head sewing machine includes a
main sewing table, and an extension sewing table of a desired size
detachably attached to the main sewing table, said bobbin stock
section is disposed adjacent to a front edge of the extension
sewing table so that an interval between the rotary hook and the
bobbin stock section differs depending on the size of the extension
sewing table attached to the multi-head sewing machine, and said
transfer mechanism has a reciprocal traveling distance
corresponding to the interval between the rotary hook and the
bobbin stock section.
11. A bobbin changer apparatus for a multi-head sewing machine as
claimed in claim 10 wherein said first orientation change mechanism
is disposed on the main sewing table while said second orientation
change mechanism is disposed on the extension sewing table, and
wherein, when the extension sewing table is detached from the main
sewing table, said transfer mechanism is detached from said first
and second orientation change mechanisms, so that individual
components can be detached into three blocks: a block associated
with the main sewing table; a block associated with the extension
sewing table; and a block associated with said transfer
mechanism.
12. A bobbin changer apparatus for a multi-head sewing machine
having a plurality of machine heads, in which said bobbin changer
apparatus recited in claim 4 is provided for each of rotary hooks
that are provided in corresponding relation to the machine
heads.
13. A bobbin changer apparatus for a multi-head sewing machine as
claimed in claim 12 wherein said transfer mechanism includes a
timing belt for holding said bobbin grasping device so that the
timing belt is driven to move together with said bobbin grasping
device, and which further comprises a common drive-force
transmission mechanism for transmitting a drive force of a common
motor to said timing belt of said transfer mechanism of each of
said bobbin changer apparatus corresponding to the machine
heads.
14. A bobbin changer apparatus for a multi-head sewing machine as
claimed in claim 8 wherein the multi-head sewing machine includes a
sewing table detachable from a body of the sewing machine, said
bobbin stock section is disposed adjacent to a front edge of the
detachable sewing table, said first orientation change mechanism is
disposed on the body of the sewing machine while said second
orientation change mechanism is disposed on the detachable sewing
table, and wherein, when the sewing table is detached from the body
of the sewing machine, said transfer mechanism is detached from
said first and second orientation change mechanisms, so that
individual components can be detached into three blocks: a block
associated with the body of the sewing machine; a block associated
with the detachable sewing table; and a block associated with said
transfer mechanism.
15. A bobbin changer apparatus for replacing a lower thread bobbin
to be mounted in a rotary hook of a sewing machine, said bobbin
changer apparatus comprising: a bobbin grasping device for grasping
a bobbin case by means of a chuck section; an actuator selectively
performing a grasp operation to cause the bobbin case to be grasped
by the chuck section when the chuck section is empty and a release
operation to release the bobbin case from the chuck section
grasping the bobbin case; a transfer mechanism for reciprocally
transferring said bobbin grasping device together with said
actuator between the rotary hook of the sewing machine and the
bobbin stock section; a first cam mechanism for orienting the chuck
section of said bobbin grasping device toward the rotary hook of
the sewing machine during transfer, by said transfer mechanism, of
said bobbin grasping device toward the rotary hook; and a second
orientation change mechanism for orienting the chuck section of
said bobbin grasping device toward the bobbin stock section during
transfer, by said transfer mechanism, of said bobbin grasping
device toward the bobbin stock section; and means for positioning
the chuck section of said bobbin grasping device in a neutral
posture in a middle portion of a transfer stroke between said first
cam mechanism and said second cam mechanism, wherein replacement of
a bobbin case having a lower thread bobbin accommodated therein is
carried out by the bobbin case being taken into or released from
the chuck section at a position where the chuck section contacts
the rotary hook or the bobbin stock section.
Description
TECHNICAL FIELD
[0001] The present invention relates to a bobbin changer apparatus
for automatically replacing a bobbin case having accommodated
therein a lower thread bobbin to be mounted in a rotary hook of a
sewing machine.
BACKGROUND ART
[0002] Lower thread change devices are arranged to, when a bobbin,
contained in a bobbin case mounted in a rotary hook supported on a
rotary hook base, has run out of a lower thread, automatically
replace the empty bobbin case with a new bobbin case containing a
bobbin with a sufficient lower thread wound thereon, and such lower
thread change devices have been known as bobbin changers. In
Japanese Patent Application Laid-open Publication No. 2000-157774,
there is disclosed a multi-head sewing machine equipped with a
plurality of machine heads, where a bobbin changer is provided for
each of the machine heads (i.e., for each of the rotary hook bases)
and drive mechanisms of the individual bobbin changers are drivable
via a same or common drive source.
[0003] In the known bobbin changers, a bobbin stock section (or
bobbin replacing or changing cassette) is disposed on a portion of
a sewing table closer to a human operator (i.e., adjacent to a
front edge of the sewing table), and a transfer mechanism is
provided to reciprocally transfer a bobbin grasping device (or
bobbin chuck mechanism) between the rotary hook supported on the
rotary hook base located beneath the machine head disposed adjacent
to the rear edge of the sewing table and the bobbin stock section.
The bobbin stock section (or bobbin changing cassette) is equipped
with a plurality of bobbin cases and delivers or receives a bobbin
case to or from the bobbin changer. Namely, when a thread wound on
a lower thread bobbin mounted in the rotary hook base has run out,
the bobbin grasping device is moved, via the transfer mechanism, to
the rotary hook in response to a lower thread runout detection
signal, takes out, from the rotary hook, the bobbin case having the
empty bobbin contained therein, then moved, via the transfer
mechanism, to the bobbin stock section with the taken-out bobbin
case grasped by the device, and then delivers the bobbin case to an
empty bobbin stock position of the bobbin stock section. After
that, the bobbin stock section is rotated through a predetermined
angle to allow the bobbin grasping device to takes out a new bobbin
case, containing a bobbin with a sufficient lower thread wound
thereon, from another bobbin stock position of the bobbin stock
section. Then, the bobbin grasping device is moved, via the
transfer mechanism, to the rotary hook with the taken-out new
bobbin case held by the device and places the new bobbin case in
the empty rotary hook. Bobbin change or replacement is
automatically carried out generally in accordance with such an
operational sequence.
[0004] With such bobbin changers, the human operator only has to
perform operation for retrieving an empty bobbin case from the
bobbin stock section provided adjacent to the front edge of the
sewing table and replenishing or resupplying the bobbin stock
section with a new bobbin case containing a bobbin having a
sufficient lower thread wound thereon. Thus, the bobbin changers
allow the human operator to perform necessary operation with
considerable ease. Where such a bobbin changer is not used, the
human operator has to get into under the sewing table and manually
change bobbin cases in the rotary hook on the hook base, which is
very cumbersome. Therefore, in large-size industrial sewing
machines, such as multi-head type sewing machines, (not only
ordinary sewing machines but also embroidery sewing machines), the
bobbin changers of the aforementioned type are becoming
indispensable in order to achieve an enhanced efficiency of sewing
operation. However, with the conventional bobbin changers, there is
still a room and demand for improvement.
[0005] In the bobbin changer disclosed in the above-mentioned No.
2000-157774 publication, for example, a guide plate for guiding the
movement of the bobbin grasping device has a linear first guide
groove, and a second groove having orientation-changing slanted
portions near opposite ends thereof. By being guided by the slanted
portions of the second groove, the orientation of a chuck section
of the bobbin grasping device can be changed at each end of a
transfer stroke of the grasping device. Namely, the transfer
mechanism (i.e., guide plate) has integrally incorporated therein
mechanisms for changing the orientation of the chuck section at the
opposite ends of the transfer stroke.
[0006] As well known in the art, the sewing machines come in
variety of sizes depending on, for example, the range to be
embroidered, and the distance from the rotary hook base to the
front edge of the sewing table, i.e. from the rotary hook to the
bobbin stock section, also differs depending on the size of the
sewing machine. Thus, guide plates of various types (sizes) would
be required which correspond to different distances from the rotary
hook to the bobbin stock section. With the aforementioned
conventional technique, where the guide plate has integrally
incorporated therein the mechanisms for changing the orientation of
the chuck section at the opposite ends of the transfer stroke, it
is necessary to separately make guide plates, having integrally
incorporated therein the mechanisms for changing the orientation of
the chuck section at the opposite ends of the transfer stroke, in
various sizes and constructions suited for various types of sewing
machines, which tends to take a lot of time and labor in
manufacturing of component parts and therefore result in high
cost.
[0007] Generally, in large-size sewing machines, a front section of
the sewing table is dividable and thus detachable when the sewing
machine is to be transported; this is for reducing the size of the
machine in packed form and facilitating carry-in and carry-out of
the machine to and from a building. Because the guide plate of the
bobbin changer, fixed to the underside of the sewing table, extends
from the front section (i.e., detachable section) to the rear
section (i.e., non-detachable section) of the sewing table, the
bobbin changer (at least the guide plate) has to be detached first
of all in order to detach the front sewing table section. Then,
after the sewing machine has been carried into a building, the
front sewing table section is again attached (i.e., reattached) to
the body of the sewing body, and then the bobbin changer is again
fixed to the underside of the sewing table. Such operation tends to
take a lot of time and labor. Particularly, because positioning of
the bobbin grasping device relative to the rotary hook and bobbin
stock section depends on the positions of the orientation-changing
mechanisms in the opposite end portions of the guide plate,
position adjustment of the guide plate tends to be very
time-consuming.
SUMMARY OF THE INVENTION
[0008] In view of the foregoing, it is an object of the present
invention to provide a bobbin changer apparatus of a novel
construction with various improvements over the conventional
counterparts. It is another object of the present invention to
provide an easy-to-use bobbin changer apparatus which can readily
deal with a difference in traveling distance of a bobbin grasping
device. It is still another object of the present invention to
provide a bobbin changer apparatus which can be detached and
reattached without cumbersome operation even where it is applied to
a dividable sewing table.
[0009] According to one aspect of the present invention, there is
provided a bobbin changer apparatus for replacing a lower thread
bobbin to be mounted in a rotary hook of a sewing machine, which
comprises: a bobbin grasping device for grasping a bobbin case at a
distal end of a chuck section; a transfer mechanism for
reciprocally transferring the bobbin grasping device between the
rotary hook of the sewing machine and a bobbin stock section; a
first orientation change mechanism for orienting the chuck section
of the bobbin grasping device toward the rotary hook of the sewing
machine during transfer, by the transfer mechanism, of the bobbin
grasping device toward the rotary hook; and a second orientation
change mechanism for orienting the chuck section of the bobbin
grasping device toward the bobbin stock section during transfer, by
the transfer mechanism, of the bobbin grasping device toward the
bobbin stock section. In the present invention, the first and
second orientation change mechanisms are detachable from the
transfer mechanism.
[0010] Because the first and second orientation change mechanisms,
provided on a traveling path of the transfer mechanism, are
detachable from the transfer mechanism, the first and second
orientation change mechanisms of the same construction can be used
even where the transfer mechanism is constructed to be able to deal
with any desired reciprocal traveling distances. Thus, even where
the traveling distance of the bobbin grasping device differs
depending on the depth (dimension in the front-rear direction) of
the sewing table, the present invention can appropriately deal with
a difference in traveling distance of the bobbin grasping device,
without requiring large amounts of time and labor in making of
component parts, at relatively low cost, thereby achieving an
easy-to-use bobbin changer apparatus with a general versatility.
Further, in the present invention, the first and second orientation
change mechanisms and the transfer mechanism between the
orientation change mechanisms are detachable from each other, and
thus, in detachment operation to be performed in the case where the
bobbin changer apparatus is applied to a sewing table of a type
dividable into a front section and a main section, the first and
second orientation change mechanisms can be left mounted to the
main and front sections, respectively, of the sewing table with
only the transfer mechanism detached. Thus, with the present
invention, the detachment operation does not require a great amount
of time and labor, and, in reassembly of the machine, there is no
need at all for cumbersome position adjustment of the orientation
change mechanisms (because the orientation change mechanisms need
not be detached in the detachment operation).
[0011] According to another aspect of the present invention, there
is provided a bobbin changer apparatus for replacing a lower thread
bobbin to be mounted in a rotary hook of a sewing machine, which
comprises: a bobbin grasping device for grasping a bobbin case at a
distal end of a chuck section; a transfer mechanism for
reciprocally transferring the bobbin grasping device between the
rotary hook of the sewing machine and a bobbin stock section; a
first orientation change mechanism for orienting the chuck section
of the bobbin grasping device toward the rotary hook of the sewing
machine during transfer, by the transfer mechanism, of the bobbin
grasping device toward the rotary hook; and a second orientation
change mechanism for orienting the chuck section of the bobbin
grasping device toward the bobbin stock section during transfer, by
the transfer mechanism, of the bobbin grasping device toward the
bobbin stock section, and in which the bobbin grasping device
includes a moving body section linearly movable by the transfer
mechanism, the chuck section pivotally supported on the moving body
section, and a spring member for normally biasing the chuck section
toward a predetermined neutral position. Further, in the bobbin
changer apparatus of the present invention, the first orientation
change mechanism orients the distal end of the chuck section toward
the rotary hook against a biasing force of the spring member, and
the second orientation change mechanism orients the distal end of
the chuck section toward the bobbin stock section against the
biasing force of the spring member. The bobbin changer apparatus
thus arranged can achieve the superior benefit that it is possible
to perform orientation control, i.e. posture control, of the chuck
section with a simple construction.
[0012] As an example, the transfer mechanism may include a guide
section for guiding the bobbin grasping device through transfer
between the rotary hook and the bobbin stock section, and a drive
section for reciprocally transferring the bobbin grasping device
along the guide section. Thus, the transfer mechanism can be
simplified in construction. Each of the first and second
orientation change mechanisms has a slanted cam surface, and the
bobbin grasping device includes a cam follower in relation to the
chuck section. The chuck section may be caused to pivot to
appropriately change the orientation of the distal end by the cam
follower moving along the cam surface. Thus, the orientation change
mechanisms in the present invention can be simplified in
construction.
[0013] According to still another aspect of the present invention,
there is provided a bobbin changer apparatus for replacing a lower
thread bobbin to be mounted in a rotary hook of a sewing machine,
which comprises: a bobbin grasping device for grasping a bobbin
case at a distal end of a chuck section; and a transfer mechanism
for reciprocally transferring the bobbin grasping device between
the rotary hook of the sewing machine and a bobbin stock section,
and in which the bobbin grasping device comprises: an arm-grasping
claw for pulling out a bobbin case arm; a drive section for causing
the arm-grasping claw to pivot so as to pull out the bobbin case
arm; and an arm-engaging protrusion for engaging with the bobbin
case arm having been pulled out by the arm-grasping claw. Thus, the
bobbin case grasping structure of the bobbin grasping device can be
simplified while still ensuring reliable grasping of the bobbin
case.
[0014] According to still another aspect of the present invention,
there is provided a bobbin changer apparatus for replacing a lower
thread bobbin to be mounted in a rotary hook of a sewing machine,
which comprises: a bobbin grasping device for grasping a bobbin
case by means of a chuck section; an actuator selectively
performing a grasp operation to cause the bobbin case to be grasped
by the chuck section when the chuck section is empty and a release
operation to release the bobbin case from the chuck section
grasping the bobbin case; a transfer mechanism for reciprocally
transferring the bobbin grasping device together with the actuator
between the rotary hook of the sewing machine and the bobbin stock
section; a first cam mechanism for orienting the chuck section of
the bobbin grasping device toward the rotary hook of the sewing
machine during transfer, by the transfer mechanism, of the bobbin
grasping device toward the rotary hook; and a second orientation
change mechanism for orienting the chuck section of the bobbin
grasping device toward the bobbin stock section during transfer, by
the transfer mechanism, of the bobbin grasping device toward the
bobbin stock section; and a section for positioning the chuck
section of the bobbin grasping device in a neutral posture in a
middle portion of a transfer stroke between the first cam mechanism
and the second cam mechanism. In this bobbin changer apparatus,
replacement of a bobbin case having a lower thread bobbin
accommodated therein is carried out by the bobbin case being taken
into or released from the chuck section at a position where the
chuck section contacts the rotary hook or the bobbin stock
section.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a schematic view showing an example external
appearance of a multi-head embroidery sewing machine employing a
bobbin changer apparatus in accordance with the present
invention;
[0016] FIG. 2 is a side view of the bobbin changer apparatus
according to the embodiment of the present invention;
[0017] FIG. 3 is a side view, similar to FIG. 2, of the bobbin
changer apparatus, which, in order to enhance the visibility, shows
guide rods in shortened length and various elements in enlarged
scale
[0018] FIG. 4 is a plan view showing of a bobbin chuck unit of
FIGS. 2 and 3 in another posture;
[0019] FIG. 5 is a view taken in a direction of arrow A of FIG. 4
and shows some elements in section;
[0020] FIG. 6 is a view showing the bobbin chuck unit in another
posture as viewed in the same direction as FIG. 5;
[0021] FIGS. 7(a)-7(c) are side views extractively showing various
operational states of a torsion spring of the bobbin chuck
unit;
[0022] FIGS. 8(a)-8(c) are side views extractively showing various
operational states of a chuck torsion spring of the bobbin chuck
unit;
[0023] FIG. 9 is a side view showing detailed constructions of
first and second orientation change mechanisms, which also
schematically shows a movement trajectory of a roller during a
series of orientation change operations;
[0024] FIG. 10 is a view schematically showing a movement
trajectory of the chuck section during a series of orientation
change operations;
[0025] FIG. 11 is a top plan view showing the chuck section of the
bobbin chuck unit;
[0026] FIG. 12 is a top plan view showing how the chuck section
grasps a bobbin case; and
[0027] FIG. 13 is a side view showing a modification of a mounting
structure of the first orientation change mechanism to be provided
on the side of a rotary hook of the sewing machine.
DETAILED DESCRIPTION OF THE INVENTION
[0028] [General External Appearance of Multi-Head Embroidery Sewing
Machine]
[0029] FIG. 1 is a schematic view showing an example external
appearance of a multi-head embroidery sewing machine employing a
bobbin changer apparatus in accordance with the present
invention.
[0030] As known in the art, the multi-head embroidery sewing
machine 1 at least includes a plurality of machine heads 2, rotary
hook bases 5 (FIG. 2) provided beneath a main (body) sewing table 3
in corresponding relation to the machine heads 2, rotary hooks 6
(FIG. 2) provided on the individual hook bases. Extension sewing
table 4 is detachably attached to a front edge portion of the main
sewing table 3. Further, although not shown for simplification of
illustration, an embroidery frame drive mechanism is provided on
the sewing tables. Further, the bobbin changer apparatus 7
according to an embodiment of the present invention is provided for
each of the rotary hooks 6 corresponding to the machine heads 2.
Although the bobbin changer apparatus 7 are not visible in FIG. 1
because they are disposed on the undersides of the sewing tables 3
and 4, only a reference numeral of the apparatus 7 is indicated in
the figure. Bobbin stock sections 8 are provided, on a portion of
the underside of the extension sewing table 4 closer to a human
operator, in corresponding to the bobbin changer apparatus 7.
Throughout the accompanying drawings, elements or portions
necessary for the explanation are illustrated with illustration of
elements or portions unnecessary for the explanation omitted. Thus,
note that even elements not shown in the figures are provided in
actual products, and that there are elements shown in some of the
figures but not shown in others of the figures.
[0031] [General Setup of the Bobbin Changer Apparatus 7]
[0032] FIG. 2 is a side view of the bobbin changer apparatus 7
according to the embodiment of the present invention, which shows
the apparatus 7 mounted to the undersides of the sewing tables 3
and 4. Although FIG. 2 shows only one bobbin changer apparatus 7
corresponding to one set of the machine head 2 and rotary hook 6,
the other bobbin changer apparatus 7 are constructed in the same
manner as the one shown in the figure. FIG. 3 is a side view,
similar to FIG. 2, of the bobbin changer apparatus 7, which, in
order to enhance the visibility, extractively shows only the bobbin
changer apparatus 7 and shows the individual elements thereof in
enlarged scale; however, in the figure, guide rods 21 and 22 and
endless toothed belt 25 are shown in shortened length for
convenience of illustration. For those portions not clearly visible
in FIG. 2, see FIG. 3.
[0033] The bobbin changer apparatus 7 includes a bobbin chuck unit
10 (bobbin grasping device) having a chuck section 11 provided at
its distal end for grasping or holding a bobbin case B, a transfer
mechanism 20 for reciprocally transferring the bobbin chuck unit 10
between the rotary hook 6 and the bobbin stock section 8, a first
orientation change mechanism 30 for orienting the chuck section 11
of the bobbin chuck unit 10 toward the rotary hook 6 during
transfer, by the transfer mechanism 20, of the bobbin chuck unit 10
toward the rotary hook 6, and a second orientation change mechanism
30 for orienting the chuck section 11 of the bobbin chuck unit 10
toward the bobbin stock section 8 during transfer, by the transfer
mechanism 20, of the bobbin chuck unit 10. As will be later
described, the first and second orientation change mechanisms 30
and 40 are each separable or detachable from the transfer mechanism
20.
[0034] [Description about the Transfer Mechanism 20]
[0035] The transfer mechanism 20 includes the guide rods 21 and 22
(guide section) extending in parallel with each other for guiding
the bobbin chuck unit 10 to allow the bobbin chuck unit 10 linearly
to move between the rotary hook 6 and the bobbin stock section 8,
and a drive mechanism for reciprocally transferring the bobbin
chuck unit 10 along the guide rods 21 and 22. The guide rods 21 and
22, which are each formed into an appropriate length according to a
distance between the rotary hook 6 and the bobbin stock section 8
in the sewing machine, are interconnected at their opposite ends by
means of faster members 23 and 24, to together constitute the guide
section. In the illustrated example, a drive mechanism of the
transfer mechanism 20 comprises the endless (or ring-shaped)
toothed belt 25 extending along the full length of the belt guide
rods 21 and 22. The endless toothed belt 25 is wound on and
connects between a driving belt gear 26 and driven belt gear 27
provided near opposite ends of the guide rods 21 and 22, and the
bobbin chuck unit 10 is fixed to a predetermined portion of the
endless toothed belt 25 so that the chuck unit 10 can move together
with the belt 25. The bobbin chuck unit 10 fixed to the
predetermined portion of the endless toothed belt 25 is detachable
from the belt 25 by loosening a screw 12.
[0036] The driving belt gear 26 has a shaft borne on a
predetermined portion of a first cam plate 31 constituting the
first orientation change mechanism 30 and is connected coaxially
with a driving gear 28. The driven belt gear 27 has a shaft borne
on a predetermined portion of a second cam plate 41 constituting
the second orientation change mechanism 40, and the driven belt
gear 27 is freely rotatable by being driven via the driving belt
gear 26. The driving gear 28 meshes with an interlocking shaft gear
29. The interlocking shaft gear 29 is mounted on a common
interlocking shaft 50 that is driven to rotate via a
bobbin-changing common drive motor (not shown). The common
interlocking shaft 50 extends horizontally under the main sewing
table 3, and the interlocking shaft gears 29 of the individual
bobbin changer apparatus 7, provided in corresponding relation to
the machine heads 2, are fixedly mounted on the common interlocking
shaft 50. Thus, as the bobbin-changing common drive motor rotates,
the common interlocking shaft 50 is rotated so that the
interlocking shaft gears 29 of the individual bobbin changer
apparatus 7 rotate together with the common interlocking shaft 50,
in response to which the driving gear 28 in each of the bobbin
changer apparatus 7 rotates and thus the driving belt gear 26
rotates to drive the endless toothed belt 25. Thus, the bobbin
chuck unit 10 fixed to the predetermined portion of the endless
toothed belt 25 is caused to move linearly.
[0037] [Description about the Bobbin Chuck Unit 10]
[0038] FIG. 4 is a plan view of the bobbin chuck unit 10. Whereas
the chuck section 11 is shown as oriented downward in FIG. 3, it is
shows as oriented horizontally rightward in FIG. 4. FIG. 5 is a
view taken in a direction of arrow A of FIG. 4 and shows some
elements in section; however, only some of hatchings to indicate
cross-sectional surfaces are indicated with the other hatchings
omitted to avoid complexity of illustration. FIG. 6 shows the
bobbin chuck unit 10 as viewed in the same direction as FIG. 5;
whereas the chuck section 11 is depicted as oriented horizontally
in FIG. 5, it is depicted as oriented downward in FIG. 6. In these
and other figures as well, only some of hatchings to indicate
cross-sectional surfaces are indicated with the other hatchings
omitted to avoid complexity of illustration.
[0039] The bobbin chuck unit 10 includes a moving body 13 slidably
fitted in the guide rods 21 and 22, and the chuck section 11
tiltably supported on the moving body 13 via a tilting shaft 14. As
shown in FIG. 3, the bobbin chuck unit 10 is fixed to the
above-mentioned toothed belt 25 with the toothed belt 25 held
between the underside of the moving body 13 and a belt tightening
member 15 tightened by the screw 12. The chuck section 11 includes
a chuck tilting body 11a constituting the body of the chuck section
11, and a chuck mechanism provided at the distal end of the chuck
tilting body 11a. The bobbin B is grasped or held by the chuck
mechanism, a detailed construction for which will be later
described. The chuck tilting body 11a is fixed to one end of the
tilting shaft 14, the tilting shaft 14 extends through the moving
body 13 and is tiltably or pivotally supported on the moving body
13, and a tilting-shaft actuating lever 16 is fixed to the other
end of the tilting shaft 14 opposite from the chuck tilting body
11a. Roller 17 functioning as a cam follower is freely rotatably
mounted on a distal end portion of the tilting-shaft actuating
lever 16. As will be later described, as the roller 17 rolls along
cam surfaces of the cam plates 31 and 41 of the first and second
rotation change mechanisms 30 and 40, the tilting-shaft actuating
lever 16 tilts about the axis of the tilting shaft 14, in response
to which the tilting shaft 14 pivots so that the chuck tilting body
11a and hence the chuck section 11 tilts about the tilting shaft
14.
[0040] Collar 18 is positioned around the tilting shaft 14 between
the moving body 13 and the tilting-shaft actuating lever 16. By the
width of the collar 18, there is formed a gap that permits passage
of the cam plates 31 and 41 as will be described later. Further, a
torsion spring (or helical spring) 19 is fitted over the tilting
shaft 14 between the moving body 13 and the chuck tilting body 11a.
Spring stop pin 191 is embedded in a predetermined position of the
moving body 13. Further, a tilting-movement returning pin 192 is
embedded in an end portion of the chuck tilting body 11a opposite
from the chuck mechanism with the shaft 14 interposed therebetween.
FIGS. 3 and 6 show the torsion spring 19 in a neutral position. One
end 19a of the torsion spring 19 is normally biased in a
counterclockwise direction of FIG. 3, while the other end 19b of
the spring 19 is normally biased in a clockwise direction of FIG.
3. The pins 191 and 192 are positioned to abut against the two ends
19a and 19b, respectively, of the torsion spring 19. Thus, in the
neutral position shown in FIG. 3 or 6, the pins 191 and 192 are
each held between the two ends 19a and 19b of the torsion spring
19, and an end portion of the chuck tilting body 11a having the
tilting-movement returning pin 192 provided thereon is located
uppermost, while the chuck mechanism provided opposite from the
returning pin 192 is located lowermost. Namely, the chuck section
11 is set so that its distal end is oriented downward. Further, the
roller 17 is located uppermost. FIG. 7(a) extractively shows the
torsion spring 19 in the neutral position. FIG. 8(a) extractively
shows the chuck section 11 in the neutral position.
[0041] As will be later described, as the roller 17 tilts in the
clockwise direction of FIG. 3 when the orientation of the chuck
section 11 is changed to orient its distal end toward the bobbin
stock section 8, the chuck tilting body 11a and returning 192 also
tilt in the clockwise direction of FIG. 3 so that the one end 19a
of the spring 19 is pivotally displaced in the clockwise direction.
Thus, the distal end of the chuck section 11 is oriented
horizontally leftward in FIG. 2 or 3, i.e. toward the bobbin stock
section 8. FIG. 7(b) extractively shows the torsion spring 19 in
this state, and FIG. 8(b) extractively shows the chuck section 11
in this state. Once a force acting on the roller 17 is removed, a
clockwise pivotal displacing force acting on the one end 19a of the
spring 19 is also removed so that the returning pin 192 moves
counterclockwise back to the neutral position.
[0042] As will be later described, as the roller 17 tilts in the
counterclockwise direction of FIG. 3 when the orientation of the
chuck section 11 is changed to orient its distal end toward the
rotary hook 6, the chuck tilting body 11a and returning 192 also
tilt in the counterclockwise direction so that the other end 19b of
the spring 19 is pivotally displaced in the counterclockwise
direction. Thus, the distal end of the chuck section 11 is oriented
horizontally rightward in FIG. 2 or 3, i.e. toward the rotary hook
6. FIG. 7(c) extractively shows the torsion spring 19 in this
state, and FIG. 8(c) extractively shows the chuck section 11 in
this state. Once a force acting on the roller 17 is removed, a
counterclockwise pivotal displacing force acting on the other end
19b of the spring 19 is also removed so that the returning pin 192
moves clockwise back to the neutral position.
[0043] [Description about the Orientation Change Mechanisms 30 and
40]
[0044] Now, detailed constructions of the orientation change
mechanisms 30 and 40 will be described with reference to FIGS. 2, 3
and 9. FIG. 9 is a side view showing detailed constructions of the
orientation change mechanisms 30 and 40, which schematically shows,
for reference purposes, a movement trajectory of the roller 17
during a series of orientation change operations.
[0045] The first orientation change mechanism 30 is located at an
end portion, adjacent to the rotary hook 6, of the transfer stroke
of the bobbin chuck unit 10 driven via the transfer mechanism 20
(guide rods 21 and 22). More specifically, the first orientation
change mechanism 30 mainly comprises the first cam plate 31 of a
predetermined shape as shown in FIG. 9. The first cam plate 31 has
a cam surface 31a slanted downward toward its rear end (i.e.,
toward the rotary hook 6) over a predetermined tilting movement
section of the transfer stroke, and it also has a horizontal groove
31b constituting a liner section of a predetermined length
following the cam surface 31a. The first cam plate 31 also has a
bearing section 31c supporting the rotation shaft of the
above-mentioned driving belt gear 26. The horizontal groove 31b has
a size suited to have the roller 17 of the bobbin chuck unit 10
fitted therein and to guide the roller 17 in the horizontal
direction. Further, the horizontal groove 31b extends along a
horizontal movement path of the tilting shaft 14 of the bobbin
chuck unit 10 and also allows the shaft 14 to enter the groove 31b.
The first cam plate 31 (first orientation change mechanism 30) is
accurately positioned at a predetermined location on the underside
of the main sewing table 3. The fastening member 24 located at one
end of the guide rods 21 and 22 is readily mounted, via a screw or
the like, to the thus accurately-positioned first cam plate 31.
[0046] The second orientation change mechanism 40 is located at an
end portion, adjacent to the bobbin stock section 8, of the
transfer stroke of the bobbin chuck unit 10 driven via the transfer
mechanism 20 (guide rods 21 and 22). More specifically, the second
orientation change mechanism 40 mainly comprises the second cam
plate 41 of a predetermined shape as shown in FIG. 9. The second
cam plate 41 is constructed in a substantially similar manner to
the first cam plate 31; more specifically, the second cam plate 41
is constructed in a symmetric relation to the first cam plate 31.
Namely, the second cam plate 41 has a cam surface 41a slanted
downward toward its front end (i.e., toward the bobbin stock
section 8) over a predetermined tilting movement section of the
transfer stroke, and it also has a horizontal groove 41b
constituting a liner section of a predetermined length following
the cam surface 41a. The second cam plate 41 also has a bearing
section 41c supporting the rotation shaft of the above-mentioned
driven belt gear 27. The second cam plate 41 (second orientation
change mechanism 40) is accurately positioned and attached to a
predetermined location on the underside of the extension sewing
table 4 via a screw or the like. The fastening member 23 located at
the other end of the guide rods 21 and 22 is readily mounted, via a
screw or the like, to the thus accurately-positioned second cam
plate 41. Thus, after the cam plates 31 and 41 have been accurately
positioned and fixed to the undersides of the sewing tables 3 and
4, even where the elongated guide unit, comprising the guide rods
21 an 22 and fastening members 23 and 24, are removed as necessary,
the accurately-positioned state can be maintained in and around the
important orientation change mechanisms with no adverse influence
on the mounting accuracy of the cam plates 31 and 41. Stated
differently, even if the elongated guide unit, comprising the guide
rods 21 and 22 and fastening members 23 and 24, are removed as
necessary, the guide unit can be reattached to the cam plates 31
and 41 without the human operator giving any consideration to
securement of reproducibility of the positioning accuracy of the
orientation change mechanisms 30 and 40.
[0047] [Travel and Orientation Change of the Bobbin Chuck Unit
10]
[0048] The following paragraphs describe the orientation change, by
the orientation change mechanisms 30 and 40, of the bobbin chuck
unit 10 with reference to FIGS. 9 and 10 and other figures. FIG. 10
is a view schematically showing a movement trajectory of the chuck
section 11 (chuck tilting body 11a) during a series of orientation
change operations.
[0049] When the roller 17 of the bobbin chuck unit 10 is not
approaching any of the cam plates 31 and 41 located at the opposite
ends of the transfer stroke, the chuck section 11 is kept in the
neutral position, through the aforementioned operation of the
torsion spring 19, with the chuck mechanism at its distal end
oriented downward, as illustrated in FIGS. 2, 3, 8(a), etc. Such a
section is indicated as a "neutral section" in FIG. 9. In this
neutral position, the roller 17 is located in the uppermost
position (see FIGS. 7(a) and 8(a)), as set forth above. As the
bobbin chuck unit 10 moves toward the rotary hook 6 (i.e.,
rightward in FIGS. 2, 3, 9, etc.), the roller 17 is brought into
abutment against the uppermost portion of the cam surface 31a of
the first cam plate 31. Position where the roller 17 is located at
that time is indicated in FIG. 9 by reference numeral 17a. As the
bobbin chuck unit 10 further moves toward the rotary hook 6, the
roller 17 tilts, about the tilting shaft 14, downward in the
counterclockwise direction along the cam surface 31a extending
rightwardly and downwardly, in response to which the tilting-shaft
actuating lever 16 and shaft 14 pivotally tilt in the same
direction so that the chuck tilting body 11a tilts in the
counterclockwise direction about the tilting shaft 14 and thus the
chuck mechanism at the distal end of the chuck tilting body 11a
gradually pivots upwardly in the counterclockwise direction so as
to be oriented toward the rotary hook 6. After the roller 17
reaches the lowermost portion of the cam surface 31a, it moves
horizontally while being kept fitted in the horizontal groove 31b.
While the roller 17 is fitted in the horizontal groove 31b, the
roller 17 is kept in a relationship with the moving body 13 as
shown in FIG. 7(c) and the chuck mechanism at the distal end of the
chuck tilting body 11a is oriented horizontally rightward (i.e.,
toward the rotary hook 6) as shown in FIG. 8(c). Section over which
the roller 17 moves horizontally while being kept fitted in the
horizontal groove 31b is indicated in FIG. 9 as "linear section".
In this "linear section", the chuck mechanism at the distal end of
the chuck tilting body 11a further moves linearly rightward in an
orientation facing the rotary hook 6 and ultimately reaches the
rotary hook 6, so that it picks up a bobbin case B (in this case,
the lower thread bobbin contained in the bobbin case B is normally
empty) from the rotary hook 6 or places a bobbin B (in this case,
the lower thread bobbin contained in the bobbin case B normally has
a sufficient lower thread wound thereon) in the rotary hook 6. At
the end of the "linear section", the tilting shaft 14 reaches a
position indicated in FIG. 9 by reference numeral 14a.
[0050] Next, the above-mentioned motor is rotated in the reverse
direction to cause the bobbin chuck unit 10 to travel in an
opposite direction from the aforementioned direction (i.e., in a
leftward direction in FIG. 9). If the roller 17 deviates from the
horizontal groove 31b during the travel, the pin 192 is urged in
the clockwise direction, by the biasing force of the torsion spring
19, so that the roller 17 moves upward in the clockwise direction
along the cam surface 31a extending leftwardly and upwardly. When
the roller 17 has deviated from the uppermost portion of the cam
surface 31a, the chuck section 11 (chuck tilting body 11a) is
brought to the neutral position (see FIGS. 7(a) and 8(a)) as
described above. Then, as the bobbin chuck unit 10 further moves
toward the bobbin stock section 8 (i.e., leftward in FIGS. 2, 3, 9,
etc.), the roller 17 is brought into abutment against the uppermost
portion of the cam surface 41a of the second cam plate 41. Position
where the roller 17 is located at that time is indicated in FIG. 9
by reference numeral 17b. As the bobbin chuck unit 10 further
moves, the roller 17 tilts, about the tilting shaft 14, downward in
the clockwise direction along the cam surface 41a extending
leftwardly and downwardly, in response to which the tilting-shaft
actuating lever 16 and shaft 14 pivotally tilt in the same
direction so that the chuck tilting body 11a tilts in the clockwise
direction about the tilting shaft 14 and thus the chuck mechanism
at the distal end of the chuck tilting body 11a gradually pivots
upwardly in the clockwise direction so as to be oriented toward the
bobbin stock section 8. After the roller 17 reaches the lowermost
portion of the cam surface 41a, it moves horizontally while being
kept fitted in the horizontal groove 41b. While the roller 17 is
fitted in the horizontal groove 41b, the roller 17 is kept in a
relationship with the moving body 13 as shown in FIG. 7(b) and the
chuck mechanism at the distal end of the chuck tilting body 11a is
oriented horizontally leftward (i.e., toward the bobbin stock
section 8) as shown in FIG. 8(b). Section over which the roller 17
moves horizontally while being kept fitted in the horizontal groove
41b is indicated in FIG. 9 as "linear section". In this "linear
section", the chuck mechanism at the distal end of the chuck
tilting body 11a further moves linearly leftward in an orientation
facing the bobbin stock section 8 and ultimately reaches the bobbin
stock section 8, so that it picks up a bobbin case B (in this case,
the lower thread bobbin contained in the bobbin case B normally has
a sufficient thread wound thereon) from the bobbin stock section 8
or places a bobbin B (in this case, the lower thread bobbin
contained in the bobbin case B is normally empty) in the bobbin
stock section 8. At the end of the "linear section", the tilting
shaft 14 reaches a position indicated in FIG. 9 by reference
numeral 14b.
[0051] Next, the above-mentioned motor is rotated in the forward
direction to cause the bobbin chuck unit 10 to travel in the
rightward direction in FIG. 9. If the roller 17 deviates from the
horizontal groove 41b during the travel, the pin 192 is urged in
the counterclockwise direction, through the biasing force of the
torsion spring 19, so that the roller 17 moves upward in the
counterclockwise direction along the cam surface 41a extending
rightwardly and upwardly. When the roller 17 has deviated from the
uppermost portion of the cam surface 41a, the chuck section 11
(chuck tilting body 11a) is brought to the neutral position (see
FIGS. 7(a) and 8(a)) as described above.
[0052] In the above-described manner, the orientation of the chuck
section 11 of the bobbin chuck unit 10 can be automatically changed
within a range of 180 degrees depending on the transfer stroke.
[0053] [Description about the Chuck Mechanism]
[0054] Now, a description will be given about an embodiment of the
chuck mechanism of the chuck section 11.
[0055] FIG. 11 is a top plan view of the chuck section 11 of the
bobbin chuck unit 10, which particularly shows the distal end of
the chuck section 11 contacting the rotary hook 6 in order to pick
up a bobbin case B from the rotary hook 6 or immediately after a
bobbin B has been placed in the rotary hook 6. FIG. 12 is a top
plan view of the chuck section 11 grasping or holding a bobbin case
B. Note that, although the bobbin case B and bobbin within the
bobbin case B are generally shown in section in FIGS. 11 and 12,
illustration of hatchings is omitted.
[0056] The distal end of the chuck section 11 is formed as a
posture retaining member 11b having a concavely-curved edge
corresponding to a convexly-curved surface of the bobbin case B,
and a bobbin-arm grasping claw 11c is pivotally supported on a
predetermined portion of the distal end of the chuck section 11.
Grasping-claw opening/closing lever 11d is pivotally supported on
the same shaft as the bobbin-arm grasping claw 11c and at a
predetermined angle relative to the grasping claw 11c, and the
grasping-claw opening/closing lever 11d is connected at its one end
to a rod of a claw opening/closing lever 11e. The claw
opening/closing lever 11e comprises, for example, an air cylinder;
however, it may be any other actuator. As illustrated in FIG. 11,
when the rod of the cylinder 11e is in a contracted position, the
grasping claw 11c is kept in an opened position with no bobbin case
B grasped thereby.
[0057] With reference to FIG. 11, a description will be given about
how a bobbin case B is picked up from the rotary hook 6 by the
chuck section 11. As seen in FIG. 11, when the chuck section 11 and
rotary hook 6 are in a predetermined relationship for
delivery/receipt of a bobbin case B between the chuck section 11
and the rotary hook 6, the distal end of the opened grasping claw
11c is snugly received in a claw inserting gap formed in a closed
bobbin case arm B1 of the bobbin case B near the distal end of the
arm B1. As the rod of the cylinder 11e is extended under such
conditions, the grasping claw 11c pivots, about a pivot point, in
the counterclockwise direction in the figure through a link
structure between the grasping-claw opening/closing lever 11d and
the grasping claw 11c. During that time, the distal end of the claw
1e in the claw inserting gap engages the inner surface of the
bobbin case arm B1 to open the arm B1 outwardly. Arm support
section 11g and arm window protrusion 11f are provided on
predetermined portions of the posture retaining member 11b. The
bobbin case arm B1 opened by the grasping claw 11c is supported by
the arm support section 11g, and the arm window protrusion 11f is
brought into tight engagement with an edge of an open window B2
formed in the bobbin case arm B1. In the aforementioned manner, the
bobbin case arm B1 is grasped between the grasping claw 11c and the
arm support section 11g, the arm window protrusion 11f is tightly
engaged with the edge of the open window B2 and the bobbin case B
is firmly supported along its surface by the posture retaining
member 11b, as shown in FIG. 12, as a result of which the bobbin
case B as a whole can be firmly grasped by the chuck section 11.
Although not shown, a helical spring is provided on the pivot of
the grasping claw 11c for normally biasing the grasping claw 11c
toward an opened position as shown in FIG. 11. Therefore, once a
drive force for extending the cylinder 11e is removed, the grasping
claw 11c returns to the opened position as shown in FIG. 11, to
thereby release the bobbin case B having so far been grasped
thereby. In the aforementioned manner, the grasp and release, by
the chuck section 11, of the bobbin case B is controlled through
control of the cylinder 11e.
[0058] [Explanation about the Bobbin Stock Section 8]
[0059] The bobbin stock section 8 may be constructed in the
conventionally-known manner. As seen in FIG. 2 or 10, the bobbin
stock section 8 includes four bobbin case stock positions extending
radially and angularly spaced from one another at intervals of 90
degrees, and one of the stock positions is positioned, through
rotation of an indexing drive shaft 81, at a predetermined
take-in/take-out position 8a for access by the bobbin chuck unit
10. The indexing drive shaft 81 extends in a transverse direction
of the sewing machine, as shown in FIG. 1, to perform indexing
control on each of the bobbin stock positions in each of the bobbin
changer apparatus 7 in the sewing machine. When, for example, an
empty bobbin case B is to be received from the bobbin chuck unit
10, any one of the stock positions which is empty is positioned at
the predetermined take-in/take-out position 8a. Bobbin case B
having accommodated therein a bobbin with a sufficient lower thread
wound thereon is set in advance at least one of the stock
positions. Then, the bobbin stock section 8 receives, at the empty
stock position positioned at the predetermined take-in/take-out
position 8a, the empty bobbin case B having been taken out and
transferred from the rotary hook 6 by the bobbin chuck unit 10.
After that, the indexing drive shaft 81 is rotated to turn the
bobbin stock section 8 so that the stock position, where is pre-set
the bobbin case B having accommodated therein a bobbin with a
sufficient lower thread wound thereon, is positioned at the
predetermined take-in/take-out position 8a. Then, the bobbin case B
now positioned at the predetermined take-in/take-out position 8a is
picked up by the bobbin chuck unit 10 and transferred to and placed
in the rotary hook 6. In this way, the lower-thread-bobbin change
can be carried out automatically. Generally, replenishment or
resupply, to the bobbin stock section 8, of a new bobbin case B
having accommodated therein a bobbin with a sufficient lower thread
wound thereon and withdrawal of an empty bobbin case B are
performed manually by the human operator. Therefore, that the
bobbin stock section 8 is located on the front edge portion of the
sewing table 4 means that manual operation to be performed by the
human operator can be facilitated. However, the present invention
is not so limited, and the resupply and withdrawal of bobbin cases
B to and from the bobbin stock positions of the bobbin stock
section 8 may be automatized as necessary.
[0060] [Explanation about Diassembly/Assembly Performance]
[0061] As noted above, the first cam plate 31, which is the first
orientation change mechanism 30, can be accurately positioned and
mounted to the underside of the main sewing table 3, while the
second cam plate 41, which is the second orientation change
mechanism 40, can be accurately positioned and mounted to the
underside of the extension sewing table 4. Further, each of the
bobbin stock sections 8 can be accurately positioned and mounted to
the underside of the extension sewing table 4, as shown in FIG. 2.
In this case, a common mounting member 9, having bolt holes etc.
accurately formed therein for mounting the cam plate 41 and bobbin
stock section 8, can be accurately positioned and mounted to the
underside of the extension sewing table 4 so that the cam plate 41
and bobbin stock section 8 are mounted to the common mounting
member 9, as illustrated in FIG. 2.
[0062] In manufacture of the multi-head embroidery sewing machine
in accordance with the instant embodiment of the present invention,
the sewing machine may be manufactured, packed and transported to a
predetermined delivery destination with at least the extension
sewing table 4 detached from the body of the machine. Multi-head
embroidery sewing machines of the present invention are large-size
industrial machines, and many of them are shipped overseas. If such
a multi-head embroidery sewing machine is packed and transported
with the main sewing table (or machine-body-side sewing table) 3
and the extension sewing table 4 detached from each other and then,
in an ultimate delivery destination, the multi-head embroidery
sewing machine is assembled into a final product form by attaching
the extension sewing table 4 to the main sewing table or
machine-body-side sewing table 3, the overall package size can be
reduced and the package can be stored efficiently in a shipping
container, so that it is possible to significantly cut down on the
overall shipping cost.
[0063] Advantages achievable by such detachable construction have
been known so far. However, according to the conventionally-known
techniques, the bobbin changer apparatus provided on the underside
of the sewing table is integrated as a whole, and thus, when the
main sewing table and extension sewing table are to be transported
in mutually-detached form, the entire bobbin change apparatus too
has to be detached from the body of the sewing machine for the
transportation. In such a case, the entire bobbin change apparatus
has to be accurately positioned and mounted to the accurate
position after the extension sewing table is reattached to the main
sewing table, and these operations tend to be very cumbersome.
[0064] According to the instant embodiment of the present
invention, on the other hand, not only the cam plate 41 and bobbin
stock section 8 have already been accurately positioned and mounted
to the extension sewing table but also the cam plate 31 has already
been accurately positioned and mounted to the main sewing table 3
when manufacture of the sewing machine is completed in a factory.
Further, the indexing drive shaft 8, which can belong to the side
of the extension sewing table 4, may be mounted in advance to the
extension sewing table 4, and the driven belt gear 27 too may be
mounted in advance to the cam plate 41. Likewise, the driving belt
gear 26 and driving gear 28, which can belong to the side of the
main sewing table 3, may be mounted in advance to the cam plate 31,
and the interlocking gear 29, common interlocking shaft 50, etc.
too may be mounted in advance to the main sewing table 3. The
multi-head embroidery sewing machine of the invention is packed and
transported with the main sewing table 3 and extension sewing table
4 detached from each other, and then, in an ultimate delivery
destination, the multi-head embroidery sewing machine is assembled
into a final product form by attaching the extension sewing table 4
to the main sewing table or machine-body-side sewing table 3. In
this case, a single unit, comprising the two guide rods 21 and 22
interconnected by the fastener members 23 and 24 and the bobbin
chuck unit 10 equipped with the endless toothed belt 25 attached to
the guide rods 21 and 22, is packed and transported separately;
this means that a total of three packed units are transported in
this case. Thus, in assembly of the bobbin changer apparatus 7, it
is only necessary to readily mount the single unit to the cam
plates 31 and 41 on the undersides of the sewing tables 3 and 4 by
screwing or otherwise and then wind the belt 25 on the gears 26 and
27. Therefore, the bobbin changer apparatus 7 according to the
instant embodiment can be assembled with utmost ease. As a result,
it is possible to significantly cut down on the costs necessary for
the separated packing, transporting and assemblying of the entire
machine.
[0065] In addition to the merits achievable by the separated
packing, transporting and assemblying of the entire sewing machine,
the present invention can achieve other benefits by allowing the
first and second orientation change mechanisms (cam plates 31 and
41) of the same construction to be used even when the transfer
mechanism is constructed to be able to deal with any desired
reciprocal traveling distances. Namely, even where the traveling
amount of the bobbin grasping device differs depending on the depth
(dimension in the front-rear direction) of the sewing tables, the
present invention can appropriately with the differing traveling
amount of the bobbin grasping device by just changing the length of
the guide rods 21 and 22. As a result, the present invention can
achieve the superior benefits that the necessary component parts
can be made without requiring large amounts of time and labor (the
same cam plates 31 and 41 can be shared) at relatively low cost,
thereby achieving an easy-to-use bobbin changer apparatus with a
general versatility.
[0066] [Explanation about Modifications]
[0067] Whereas, in the above-described embodiment, the first
orientation change mechanism 30 associated with the rotary hook
base 5 is mounted to the main sewing table 3, the present invention
is not so limited, and the first orientation change mechanism 30
may be mounted to a suitable portion of the machine body side
(e.g., to the rotary hook base 5). FIG. 13 shows a modified example
where the first orientation change mechanism 30 is mounted to the
hook base 5. In FIG. 13, a bracket 301 of a substantial L shape is
fixed to the hook base 5, and a lower end portion of the bracket
301 is fixed to a machine frame F. The first orientation change
mechanism 30 associated with the rotary hook 5 is fixed to the
bracket 301. The common interlocking shaft 50 is borne by the
bracket 301. By the first orientation change mechanism 30 being
mounted to the hook base 5 as noted above, the positioning accuracy
of the bobbin chuck unit 10 on the side of the hook base 5 can be
further enhanced.
[0068] Further, whereas, in the above-described embodiment, the
claw 11c of the chuck section 11 of the bobbin chuck unit 10 is
driven by an air cylinder, the present invention is not so limited,
and the claw 11c of the chuck section 11 may be driven by any other
suitable means. For example, the claw 11c of the chuck section 11
may be opened/closed by push/pull operation of a wire operatively
connected to the claw 11c.
[0069] Further, in a power transmission mechanism for moving the
bobbin chuck unit 10 through rotation of the interlocking shaft 50,
there may be provided a slipping transmission mechanism which
permits rotation of the common interlocking shaft 50 even when the
bobbin chuck unit 10 is in a stationary or stopped state. For this
purpose, two disks (not shown) may be fixed to ends of the
respective shafts of the driving gear 28 and driving belt gear 26
and pressed against each other via spring members, so that the
rotation of the driving gear 28 can be transmitted to the driving
belt gear 26 through the disks resiliently pressed against each
other. Thus, even when the driving belt gear 26 is brought into a
non-rotatable state by the bobbin chuck unit 10 reaching a movement
limit, the driving gear 28 and hence the common interlocking shaft
50 can be rotated by slipping action between the two disks. Thus,
in a case where a recess is formed in part of the front edge
portion of the extension sewing table 4 so that the human operator
can enter the recess and where the traveling amount of the bobbin
chuck unit 10 differs between one bobbin changer unit 7 positioned
where the recess is located and another bobbin changer unit 7
positioned where the recess is not located, for example, it is
possible to drive the common interlocking shaft 50 to rotate in
correspondence with one of the bobbin changer units 7 having the
bobbin chuck unit 10 of the longer traveling amount. Namely, even
if the common interlocking shaft 50 continues to be driven after
the bobbin chuck unit 10 stops moving in the bobbin changer unit 7
having the bobbin chuck unit 10 of the shorter traveling amount,
the above-mentioned slipping transmission mechanism prevents the
rotation of the common interlocking shaft 50 from being
transmitted, so that the linear movement of the bobbin chuck unit
10 of the shorter traveling amount is not allowed any longer.
Further, even when there is a difference in the traveling operation
of the bobbin chuck unit 10 between a plurality of the bobbin
changer apparatus 7, the provision of the slipping transmission
mechanism allows all of the bobbin chuck units 10 to travel to
their movement limit positions by driving the common interlocking
shaft 50 so that the bobbin chuck units 10 move more than actual
traveling amounts.
[0070] Further, whereas, in the above-described embodiment, the
common interlocking shaft 50 is driven by a motor, the present
invention is not so limited, and the common interlocking shaft 50
may be driven by any other suitable means. For example, there may
be employed a mechanism for converting a linear drive force of a
linear drive source (e.g., air cylinder) into rotational motion of
the common interlocking shaft 50.
[0071] Furthermore, the bobbin changer apparatus of the present
invention may be applied to any other types of sewing machines than
embroidery sewing machines. Moreover, the bobbin changer apparatus
of the present invention may be applied to single-head sewing
machines or any other types of sewing machines than multi-head
sewing machines.
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