Information
-
Patent Grant
-
6755140
-
Patent Number
6,755,140
-
Date Filed
Wednesday, August 27, 200320 years ago
-
Date Issued
Tuesday, June 29, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 112 47001
- 112 220
- 112 225
- 112 270
- 112 302
- 112 224
-
International Classifications
-
Abstract
A sewing apparatus such as a household sewing machine includes a needle bar on which a sewing needle is mounted, a needle bar vertically moving mechanism vertically moving the needle bar, a thread cassette having a thread accommodating section accommodating a supply of thread, a cassette mount to which the thread cassette is detachably attached, a threading mechanism operated in synchronization with attachment of the thread cassette to the cassette mount when the needle bar is stopped at a predetermined position, the threading mechanism passing the thread drawn from the thread cassette through an eye of the needle mounted on the needle bar, and a threading limiting unit limiting the threading mechanism so that the threading mechanism is inoperative in a case where the thread cassette is attached to the cassette mount when the apparatus is disconnected from a power supply.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a sewing apparatus with a cassette mount to which a thread cassette is detachably attached, and more particularly to such a sewing apparatus in which a threading mechanism is rendered inoperative when the thread cassette is attached to the cassette mount while the apparatus is shut off.
2. Description of the Related Art
There has conventionally been proposed a sewing apparatus which includes a cassette mount to which a thread cassette accommodating a thread spool is detachably attached and in which a thread drawn from the thread cassette serves as a needle thread. In the sewing apparatus, the thread drawn from the thread cassette attached to the cassette mount is caught between a pair of thread tension discs of a thread tensioning mechanism. The thread extending downstream from the thread tension discs is caught on a needle thread take-up lever, and the thread extending downstream from the lever is passed through an eye of a sewing needle mounted on a needle bar.
The assignee of this application filed a Japanese patent application assigned with Application No. 2002-91558 and relating to a sewing apparatus including a thread carrying mechanism and a threading mechanism each operated in synchronization with attachment of the thread cassette to the cassette mount. The thread drawn from the thread cassette is automatically passed through the needle eye by the thread carrying mechanism and threading mechanism. In the disclosed sewing apparatus, the thread drawn from the thread cassette is caught and carried near the needle eye by the thread carrying mechanism, and the carried thread is caught by the threading mechanism to be passed through the needle eye.
In the above-described threading mechanism, a threading shaft is descended to be positioned relative to a needle bar. The threading shaft is rotated so that a threading hook is passed through a needle eye. A thread drawn from the thread cassette is carried near the needle eye by a thread carrying mechanism. The thread is caught on a distal end of the threading hook having been passed through the needle eye. The threading shaft is then rotated in the opposite direction so that the threading hook is returned through the needle eye. As a result, the thread is passed through the needle eye.
In the above-described sewing apparatus, a needle bar vertically moving mechanism is vertically moved. However, in order that passing the thread through the needle eye by the threading mechanism may be realized, the thread cassette needs to be attached to the cassette mount and the threading mechanism needs to be operated while the needle bar is stopped at a predetermined vertical position so that the needle eye is prevented from entering the interior of the sewing bed.
A needle bar rocking mechanism is provided for rocking the needle bar in the foregoing sewing apparatus. The needle bar is supported on a needle bar mount to be vertically moved. The needle bar mount is mounted on a frame so as to pivot about a horizontal axis. The threading mechanism is provided on the needle bar mount so as to be rocked together with the needle bar. The thread carrying mechanism is provided on the frame on which the needle bar mount is pivotally mounted. The thread carrying mechanism is not rocked in such a manner as the needle bar or the threading mechanism.
Accordingly, positional relations between the thread carrying mechanism and the needle bar and threading mechanism vary. The varied positional relations further vary the percentage of success in passing the thread through the needle eye by the threading mechanism. A zigzag position of the needle bar is previously set to improve the success percentage. In order that passing the thread through the needle eye by the threading mechanism may be realized, the needle bar needs to be stopped at a predetermined vertical position as described above and moreover, the thread cassette needs to be attached to the cassette mount and the threading mechanism needs to be operated while the needle bar is stopped at a predetermined vertical position.
The needle bar vertically moving mechanism and the needle bar rocking mechanism are operable when electric power is being supplied to the sewing apparatus. Accordingly, the needle bar can automatically be moved to a suitable position (a predetermined vertical position or predetermined zigzag position) for the attachment of the thread cassette to the cassette mount. Or, when the vertical position of the needle bar is unsuitable for threading, informing the user of that is suggested for the purpose of preventing attachment of the thread cassette to the cassette mount.
However, when the sewing apparatus is disconnected from the power supply or is forgotten to be connected to the power supply, for example, the needle bar cannot be moved to a predetermined position by the needle bar vertically moving mechanism and threading mechanism or informing cannot be carried out. As a result, there is a possibility that the thread cassette may be attached to the cassette mount while the needle bar is stopped at a position other than the predetermined one.
Thus, the threading mechanism is operated in synchronization with the attachment of the thread cassette in the foregoing sewing apparatus. Accordingly, in a case where the thread cassette is erroneously attached to the cassette mount during shutoff from power supply, the threading mechanism is operated even when the needle bar is stopped at a position other than the predetermined one. Consequently, the threading mechanism may be damaged or other failure may occur. As the other failure, for example, the sewing machine cannot be threaded since the needle bar is not stopped at the predetermined position. Nevertheless, the thread is uselessly drawn from the thread cassette by the threading hook and the thread carrying mechanism when the threading mechanism is operated. It is time-consuming to rewind the drawn thread onto the thread spool in the thread cassette.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a sewing apparatus in which the threading mechanism is not operated in a case where the thread cassette is attached to the cassette mount when the apparatus is disconnected from the power supply, thereby preventing any disadvantage due to inadvertent operation of the threading mechanism during disconnection from the power supply.
The present invention provides a sewing apparatus comprising a needle bar on which a sewing needle is mounted, a needle bar vertically moving mechanism vertically moving the needle bar, a thread cassette having a thread accommodating section accommodating a supply of thread, a cassette mount to which the thread cassette is detachably attached, a threading mechanism operated in synchronization with attachment of the thread cassette to the cassette mount when the needle bar is stopped at a predetermined position, the threading mechanism passing the thread drawn from the thread cassette through an eye of the needle mounted on the needle bar, and a threading limiting unit limiting the threading mechanism so that the threading mechanism is inoperative in a case where the thread cassette is attached to the cassette mount when the apparatus is disconnected from a power supply.
In the above-described sewing apparatus, the threading mechanism is operated in synchronization with attachment of the thread cassette to the cassette mount when electric power is being supplied to the apparatus. In a case where the threading mechanism is operated when the needle bar is stopped at the predetermined position, the thread drawn from the thread cassette attached to the cassette mount is passed through the eye of the needle mounted to the needle bar. Furthermore, while electric power is being supplied to the apparatus, the threading mechanism is limited by the threading limiting unit so that the threading mechanism is inoperative, although the needle bar cannot automatically be moved to the predetermined position by the needle bar vertically moving mechanism and an alarming or informing operation cannot be performed.
In a preferred form, the sewing apparatus further comprises a needle bar rocking mechanism for rocking the needle bar and a needle bar movement controlling unit controlling the needle bar vertically moving mechanism and the needle bar rocking mechanism so that the needle bar is moved to the predetermined position in a case where the thread cassette has been detached from the cassette mount while electric power is being supplied to the apparatus. In this case, the needle bar movement controlling unit may control only the needle bar vertically moving mechanism.
In another preferred form, the threading mechanism includes a moving member provided on the cassette mount, the moving member being thrust by the thread cassette attached to the cassette mount thereby to be moved from an initial position so that the threading mechanism is operated, and the threading mechanism includes a holding unit holding the moving member at a standby position where the threading mechanism is inoperative even when the moving member is thrust by the thread cassette being attached to the cassette mount.
In further another preferred form, the holding unit includes a stopper engaging the moving member located at the standby position to hold the moving member at the standby position, an actuator switching between an engagement position where the stopper engages the moving member and a non-engagement position where the stopper is disallowed to engage the moving member, and a control unit controlling the actuator.
In the above-described construction, the actuator preferably comprises a pulse motor provided in the needle bar vertically moving mechanism for rocking the needle bar, and the threading limiting unit preferably limits the threading mechanism so that the stopper is located at the non-engagement position when the needle bar is located at the predetermined position and so that the stopper is located at the engagement position when the needle bar is located at a position other than the predetermined position.
In the above-described construction, the pulse motor preferably also serves to open and close a thread tension disc applying a tension to the thread drawn from the thread cassette, and the thread tension disc is preferably opened when the needle bar is located at the predetermined position and closed when the needle bar is located at a position other than the predetermined position.
In further another preferred form, the sewing apparatus further comprises a thread carrying mechanism operated in synchronization with attachment of the thread cassette to the cassette mount when the needle bar is stopped at the predetermined position, thereby carrying the thread from the thread cassette to a position near an eye of the needle mounted on the needle bar, and a limiting unit limiting the threading mechanism and the thread carrying mechanism so that both the threading mechanism and the thread carrying mechanism are inoperative in a case where the thread cassette is attached to the cassette mount when the apparatus is disconnected from a power supply.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention will become clear upon reviewing the following description of embodiment, made with reference to the accompanying drawings, in which:
FIG. 1
is a front view of a sewing machine in accordance with one embodiment of the present invention during attachment of a thread cassette to a cassette mount;
FIG. 2
is a front view of the sewing machine with the sewing head being eliminated;
FIG. 3
is a front view of the sewing machine with the thread cassette having been attached;
FIG. 4
is a front view of the sewing machine with the sewing head being eliminated;
FIG. 5
is a front view of the thread cassette;
FIG. 6
is a rear view of the thread cassette;
FIG. 7
is a left-hand side view of the thread cassette with the lid open;
FIG. 8
is a bottom view of the thread cassette;
FIG. 9
is a front view of the front interior of the head;
FIG. 10
is a front view of the front interior of the head in another condition;
FIG. 11
is a plan view of thread tension discs of a thread tensioning mechanism;
FIGS. 12A and 12B
are front and plan views of a thread tensioning mechanism in a closed state respectively;
FIGS. 13A and 13B
are front and plan views of a thread tensioning mechanism in an open state respectively;
FIG. 14
is a view taken along line
14
—
14
in
FIG. 12
;
FIG. 15
a left-hand side view of a thread carrying mechanism;
FIGS. 16A and 16B
are left-hand side and front views of a threading mechanism respectively;
FIGS. 17A and 17B
illustrate an operating state of the threading mechanism when a threading hook has been passed through the needle eye, and another operating state of the threading mechanism when the threading hook has been returned through the needle eye such that the thread has been passed through the needle eye, respectively;
FIGS. 18A and 18B
are a left-hand side view of a moving member and a view taken along line B—B in
FIG. 18A
, respectively;
FIG. 19
is a block diagram showing a control system of the sewing machine;
FIG. 20
illustrates a program stored by ROM in a control device; and
FIGS. 21A and 21B
illustrate a stopper and a moving member when the stopper is located at an engagement position and
FIGS. 21C and 21D
illustrate the stopper and the moving member when the stopper is located at a non-engagement position.
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention will be described with reference to the accompanying drawings. The invention is applied to a household sewing machine provided with a cassette mount to which a thread cassette having a thread accommodating section for accommodating a supply of thread is detachably attached.
Referring to
FIGS. 1
to
4
, a household sewing machine M includes a sewing bed
1
having a horizontal bed plane, a pillar
2
standing from a right end of the bed
1
, a sewing arm
3
extending leftward from an upper end of the pillar
2
so as to be opposed along the bed
1
, and a machine head
4
located at a left end of the arm
3
. The head
4
is provided with a cassette mount
5
to which a thread cassette
10
is detachably attached. A thread
11
drawn from the thread cassette
10
attached to the cassette mount
5
serves as a needle thread. The arm
3
or the head
4
thereof includes operation switches
6
(see
FIG. 15
) such as a sewing start switch, sewing finish switch, etc. The arm
3
further includes a liquid crystal display
7
and a touch panel
8
provided on the surface of the liquid crystal display.
Referring to
FIGS. 2
,
4
,
9
and
10
, in the head
4
are provided a needle bar
12
, a needle thread take-up lever
13
, a thread tensioning mechanism
14
adjusting a thread tension of the needle thread drawn from the thread cassette
10
attached to the cassette mount
5
. In the head
4
are further provided a cassette detaching mechanism
15
rendering the thread cassette
10
detachable from the cassette mount
5
when a detaching operation member
60
is operated. The head
4
further includes a threading section
16
c
(a thread carrying mechanism
16
A and a threading mechanism
16
B) and a needle bar threading mechanism
17
all of which are operated in synchronization with attachment of the thread cassette
10
to the cassette mount
5
. The head
4
still further includes a needle bar vertically moving mechanism
18
for vertically moving the needle bar
12
, a needle bar rocking mechanism
19
for rocking the needle bar
12
, and a needle thread take-up lever driving mechanism for vertically rocking a needle thread tale-up lever
13
.
The thread carrying mechanism
16
A catches the thread
11
drawn from the thread cassette
10
and carries the caught thread
11
near an eye
12
b
of a sewing needle
12
a
. The threading mechanism
16
B passes the thread
11
carried by the thread carrying mechanism
16
A through the needle eye
12
b
. The needle bar threading mechanism
17
causes the thread
11
to be caught on a thread guide H (see
FIG. 1
etc.) of the needle bar
12
.
Referring to
FIGS. 3 and 4
, the thread
11
drawn from the thread cassette
10
attached to the cassette mount
5
is placed on a thread tension shaft
40
(see
FIG. 11
) disposed between a pair of thread tension discs
41
and
42
of the thread tensioning mechanism
14
in attachment of the thread cassette
10
to the cassette mount
5
. The thread
11
extending downstream from the thread tension shaft
40
is caught on the needle thread take-up lever
13
. The thread
11
extending downstream from the needle thread take-up lever
13
is passed through the needle eye
12
b
(see FIG.
14
), whereupon the thread
11
is set in the sewing machine M so that a sewing operation can be carried out.
The bed
1
is provided with a bobbin mount (not shown) to which a bobbin (not shown) is detachably attached. A thread drawn from the bobbin serves as a bobbin thread. The bed
1
is further provided with a shuttle mechanism (not shown). When the needle and bobbin threads are set for the sewing operation and a sewing machine motor
9
(see
FIG. 19
) is driven, the needle bar
12
is vertically moved by the needle bar vertically moving mechanism
18
. The shuttle mechanism is driven in synchronization with the vertical movement of the needle bar
12
so that the needle thread
11
near the needle
12
a
lowered below a needle plate
1
a
of the bed
1
, whereupon the needle and bobbin threads are entangled to be formed into stitches.
The thread cassette
10
will now be described. Referring to
FIGS. 5
to
8
, the thread cassette
10
comprises a cassette body
20
and a lid
21
pivotally mounted on the body
20
. The cassette body
20
with the lid
21
defines therein a thread accommodating cavity
23
for accommodating a thread spool
22
serving as a supply of thread. A spool pin
24
is mounted on the lid
21
. When the lid
21
is opened forward as shown in
FIG. 7
, the thread spool
22
is allowed to be attached to and detached from the spool pin
24
. When the lid
21
is closed with the thread spool
22
attached to the spool pin
24
, the thread spool is enclosed in the thread accommodating cavity
23
.
The thread
11
extends upward from the thread spool
22
to be drawn out of the thread accommodating cavity
23
. The thread
11
further extends through a thread path
35
defined between the cassette body
20
and a left-hand end of the lid
21
. The thread
11
is then put on a first thread guard
26
a
at a left lower end of the thread cassette
10
, further extending rightward thereafter to be put on a second thread guard
26
b
at a lower end of a partition wall
27
and a third thread guard
26
c
at a right lower end of the thread cassette
10
. The thread
11
further extends forward to be put on a fourth thread guard
26
d
and is then returned to extend leftward. The thread
11
is then retained on a thread retainer
28
. Furthermore, the thread
11
extending leftward is cut by a left blade
29
of the thread retainer
28
and the resultant end is put on a fifth thread guard
26
e
near the blade
29
.
The thread cassette
10
is thus prepared for attachment to the cassette mount
5
as described above. A needle thread take-up lever guide space
30
defined at a right end of the thread cassette
10
extends substantially over the length of the cassette. The guide space
40
is open at the rear and the lower portion of the cassette. A thread tensioning space
31
is defined at a central lower end of the thread cassette
10
and open at a lower portion thereof. These spaces
30
and
31
are partitioned by a partition wall
27
.
The thread cassette
10
is descended to be inserted into the cassette mount
5
. In this case, the needle thread take-up lever
13
and a needle thread take-up lever guide
13
a
(see
FIG. 2
etc.) guiding the lever enter the guide space
30
from below the cassette, whereas the thread tensioning shaft
40
of the thread tensioning mechanism
14
and a pair of thread tension discs
41
and
42
enter the thread tensioning space
31
from below the cassette. A notch
20
a
is formed in the lower end of the rear wall of the cassette body
20
to prevent the thread tensioning shaft
40
from interference with the thread cassette
10
. When the thread cassette
10
has been inserted slightly into the cassette mount
5
, a thread part
11
a
between the thread guards
26
a
and
26
c
is caught by the needle thread take-up lever
13
in the guide space
30
.
Subsequently, when the thread cassette
10
is further inserted into the cassette mount
5
, the thread guards
26
a
and
26
b
are descended relative to the needle thread take-up lever
13
on which a thread part
11
a
is caught. However, the thread downstream the thread part
11
a
is continuously held by the thread holding portion
28
. Accordingly, the thread
11
is drawn from the thread spool
22
in the thread accommodating cavity
23
. For example, the thread part
11
a
has a generally triangular shape when two thirds of the thread cassette are inserted into the cassette mount
5
, as shown in
FIGS. 1 and 2
. When the thread cassette
10
is completely attached to the cassette mount
5
, the thread part
11
b
between the thread guards
26
a
and
26
b
is caught on the thread tensioning shaft
40
between the paired thread tension discs
41
and
42
in the thread tensioning space
31
.
The thread tensioning mechanism
14
will now be described. Referring to
FIGS. 11
to
13
B, the thread tensioning mechanism
14
includes the thread tensioning shaft
40
fixed to a frame (not shown) and extending rearward, the front thread tension disc
41
fixedly fitted with the shaft
40
, the rear thread tension disc
42
fixedly fitted with the shaft
40
so as to be brought into a face-to-face contact with the front thread tension disc, and a thread tensioning spring
42
a
comprising a compression coil spring fitted with the shaft
40
so as to urge the rear disc
42
against the front disc
41
. A drive mechanism
43
is provided for opening and closing the thread tension discs
41
and
42
and includes a pulse motor
44
.
The drive mechanism
43
includes the pulse motor
44
, a driving gear
45
, a cam member
46
, link members
47
and
48
, a pivot link member
49
, an extension coil spring
50
, a thrust link member
51
, and an opening lever
52
. The driving gear
45
is secured to an output shaft of the pulse motor
44
and is in mesh engagement with a gear
46
a
of the cam member
46
. The link member
47
has a central portion pivotally mounted on a support shaft
47
a
. The link member
47
further has an upper end with a cam follower
47
a
in engagement with a cam groove
46
b
of the cam member
46
and a lower end with a pin
47
c
in engagement with a ventral elongated hole
48
a
of the link member
48
supported so as to be moved in a right-and-left direction.
The pivot link
49
has a central portion mounted on a support shaft
49
a
so as to be pivoted about a vertical axis. The pivot link
49
is urged counterclockwise by the extension coil spring
50
. The pivot link
49
has a rear end with an engagement portion
49
b
in engagement with an elongate hole
49
b
formed in a left end of the link member
48
. The pivot link
49
has a right end with a pin
49
c
in engagement with a central elongate hole
51
b
of the thrust member
51
. The thrust link member
51
has a right end pivotally mounted on a support shaft
51
a
so as to be pivoted about a vertical axis. The opening lever
52
is pressed against a thread tension spring
42
a.
The thread tension discs
41
and
42
are closed when the cam follower
47
b
is in engagement with a cam groove
46
b
1
of the cam groove
46
b
, as shown in
FIGS. 12A and 12B
. The cam groove
46
b
1
has the same diameter as the cam groove
46
b
. The cam groove
46
b
1
spreads over about 80 degrees and maintains the cam follower
47
b
in engagement with the cam groove
46
b
1
, so that the pulse motor
44
is driven in an angular range corresponding to about 80 degrees. The reason for this is that the pulse motor
44
and the driving gear
45
serve not only as the components of the needle bar rocking mechanism
19
but also as those of the drive mechanism
43
. As a result, the needle bar
12
can be rocked while the thread tension discs
41
and
42
are closed. The needle bar rocking mechanism
19
includes the pulse motor
44
, driving gear
45
, a gear
19
a
in mesh engagement with the driving gear
45
and a cam
19
b
fixedly provided on the gear
19
a
. Rotation of the cam
19
b
produces a rocking motion of the needle bar
12
.
The cam member
46
is turned clockwise upon drive of the pulse motor
44
so that the cam follower
47
b
engages the cam groove
46
b
2
of the cam groove
46
. As the cam follower
47
b
moves to the central side of the cam member
46
, the link members
47
and
48
and the pivot link
49
are synchronously moved in the direction of arrow. The opening lever
52
is then thrust forward by a left lever
51
c
of the forwardly moving thrusting member
51
. As a result, the rear thread tension disc
42
is moved so as to be inclined such that the discs
41
and
42
are opened with a space therebetween.
When the thread cassette
10
is attached to the cassette mount
5
while the thread tension discs
41
and
42
are open, the part
11
b
of the thread
11
drawn from the thread cassette
10
is caught by the thread tension shaft
40
disposed between the discs
41
and
42
. Successively, when the pulse motor
44
is driven so that the cam member
46
is turned counterclockwise, the urging force of the extension coil spring
50
returns the pivot link
49
to the former position. Accordingly, the thread tension discs
41
and
42
are closed by the thread tensioning spring
42
a
. The chain line in
FIG. 9
shows the left needle position to which the needle bar
12
is moved while the thread tension discs
41
and
42
are open.
The thread carrying mechanism
16
A will be described. Referring to
FIGS. 9 and 15
, the thread carrying mechanism
16
A is provided on the frame on which a needle bar base
80
(see FIGS.
16
A and
16
B) is pivotally mounted and includes a threading member
70
catching the thread
11
drawn from the thread cassette
10
and a threading drive mechanism section
55
lowering the threading member
70
from a standby position (see
FIG. 9
) while the attitude of the threading member is being changed, whereby the threading member is transferred from a threading position (not shown) toward the thread carrying position (see FIG.
15
).
The threading member
70
has a pair of threading plates
71
. When the threading member
70
is at the threading position, a part of the thread
11
located downstream the needle thread take-up lever
13
is caught over the paired threading plates
71
in a tight state. Furthermore, when located at the thread carrying position, the threading member
70
is positioned relative to the position of the needle bar
12
with respect to the vertical position thereof, and the needle thread
12
a
is located between the threading plates
71
, whereupon the thread
11
is close to the needle eye
12
b
. Japanese patent application Nos. 2002-91558 and 2002-225245 both filed by the assignee of the present application disclose the above-described thread carrying mechanism and the threading member
70
in detail.
The threading mechanism
16
B will be described. Referring to
FIGS. 16A
,
16
B,
17
A and
17
B, the threading mechanism
16
B is mounted on the needle bar base
80
and includes a threading shaft
81
and slider guide shaft
82
supported on the needle bar base
80
on the left of the needle bar
12
so as to be vertically moved, a threading slider
83
fitted with upper portions of these shafts
81
and
82
so as to be vertically moved, and a hook mechanism section
84
mounted on a lower end of the threading shaft
81
.
The threading shaft
81
has two pins
85
a
and
85
b
protruding from an upper portion thereof. The upper pin
85
a
is in engagement with a spiral engagement groove
83
a
formed in the threading slider
83
, whereas the lower pin
85
b
is engageable, from above, with the engaging member
12
c
fitted with the needle bar
12
. A compression coil spring
86
is provided around the threading shaft
81
to urge the slider
83
upward relative to the threading shaft, whereby the pin
85
a
usually engages a lower end of the engagement groove
83
a
. Furthermore, another compression coil spring
87
is provided around the slider guide shaft
82
to urge the threading slider
83
upward, whereby the threading shaft
81
and the threading slider
83
are usually located at respective upper limit positions.
Referring to
FIGS. 17A and 17B
, the hook mechanism section
84
includes a threading hook
88
capable of passing through the needle eye
12
b
and having a distal end formed with a threading portion
88
a
, two guide members
89
located at both sides of the threading hook
88
respectively, and a wire
90
engageable with the threading portion
88
a
of the threading hook
88
. The threading mechanism
16
B is in the state as shown in
FIGS. 16A and 16B
when the thread cassette
10
is unattached to the cassette mount
5
. When the thread cassette
10
is inserted into the cassette mount
5
, the threading mechanism
16
B is operated in synchronization with the attachment of the thread cassette
10
.
The threading mechanism
16
B further includes a longitudinal guide shaft
91
provided on the left of the slider guide shaft
82
and a moving member
92
provided on the cassette mount
5
to be guided by the guide shaft
91
so as to be vertically moved. The moving member
92
is urged upward by an extension coil spring
93
. When the thread cassette
10
is unattached to the cassette mount
5
, the moving member
92
is usually located at an initial position (an upper limit position in a movable range) as shown in
FIGS. 16A and 16B
.
The moving member
92
is directly thrust by the thread cassette
10
attached to the cassette mount
5
. The threading mechanism
16
B is operated when the moving member
92
is thrust downward from the initial position. More specifically, a connecting member
94
is pivotally mounted via a shaft
94
a
on an upper mounting portion
92
h
of the moving member
92
. When the moving member
92
is descended from the initial position, the threading slider
83
connected via the connecting member
94
to the moving member
92
is also descended together.
When the threading slider
83
is descended, the threading shaft
81
and the hook mechanism
84
are also descended with the threading slider
83
at an initial stage. The threading shaft
81
is disallowed to be moved downward thereby to be stopped when the pin
85
b
thereof engages the engagement member
12
c
of the needle bar
12
from above, whereupon the threading shaft
81
is positioned in the vertical direction relative to the needle bar.
Subsequently, the threading slider
83
is descended relative to the threading shaft
81
. Accordingly, the pin
85
a
engages the spiral engagement groove
83
a
of the threading slider
83
thereby to be moved upward, whereupon the threading shaft
81
is turned. At this time, the hook mechanism section
84
is located near the needle
12
a
, and moreover, the thread
11
drawn from the thread cassette
10
by the thread carrying mechanism
16
A is carried near the needle
12
a
, held in front of the needle
12
a
in a stretched state. More specifically, when the threading shaft
81
is turned, the threading hook
88
of the hook mechanism
84
passes through the needle eye
12
b
as shown in
FIG. 17A
, so that the thread
11
is caught by the distal threading portion
88
a
of the threading hook
8
as shown in FIG.
17
B. When the threading shaft
81
is then turned in the opposite direction, the threading hook
88
is returned through the needle eye
12
b
such that the thread
11
is passed through the needle eye
12
b
. At this time, the thread
11
is also placed on the needle bar thread guide H by the threading mechanism
17
.
Approximately immediately after completion of passing the thread through the needle eye, the moving member
92
and the threading slider
83
are released from connection therebetween by the connecting member
94
, whereupon the threading shaft
81
, threading slider
83
, hook mechanism section
84
are returned or ascended to the former conditions as shown in
FIGS. 16A and 16B
. Furthermore, the moving member
92
is maintained at a cassette attachment position below the initial position when the thread cassette
10
is attached to the cassette mount
5
. More specifically, since the hook mechanism section
84
is spaced away from the moving member
92
, transmission of force via the moving member
92
to the hook mechanism section
84
becomes impossible.
When a detaching operation member
60
is operated during power supply to the sewing machine, the thread cassette
10
located at the cassette attachment position and the moving member
92
are released from the held conditions and the thread cassette
10
is ascended together with the moving member
92
by the urging force of the extension coil spring
93
. As a result, the upper portion of the thread cassette
10
projects from an upper part of the sewing machine M, whereby the thread cassette
10
can be detached from the cassette mount
5
. Furthermore, the moving member
92
is ascended to be returned to the initial position. When returned to the initial position and thereafter descended from the initial position, the moving member
92
is connected to the threading slider
83
by the connecting member
94
, whereupon the moving member and the connecting member are descended together.
Referring to
FIG. 9
, the cassette detaching mechanism
15
includes the detaching operation member
60
and a link
61
linked to the detaching operation member
60
. When the detaching operation member
60
is operated to be rocked about the axis
60
a
, the link
61
is rocked together with the operation member
60
so that the thread cassette
10
located at the cassette attachment position and the moving member
92
are released from the held conditions. Furthermore, the thrusting member
51
is forced to be turned so that the discs
41
and
42
of the thread tensioning mechanism
14
are opened.
The needle bar
12
and the threading mechanism
16
B are rocked. However, the thread carrying mechanism
16
A is not rocked in such a manner as the needle bar
12
and the threading mechanism
16
B are rocked. Accordingly, depending upon a zigzag position of the needle bar
12
, positional relations between the needle bar
12
and threading mechanism
16
B, and the thread carrying mechanism
16
A vary depending upon a zigzag position of the needle bar
12
. The percentage of success in passing the thread through the needle eye also varies depending upon the varying positional relations between the needle bar
12
and threading mechanism
16
B, and the thread carrying mechanism
16
A. When the thread carrying mechanism
16
A and the threading mechanism
16
B are rocked together, the weight of a rocked portion and a moving space defined inside the sewing machine M (escape) are increased, resulting in an increase in the size of the sewing machine M. Accordingly, the thread carrying mechanism
16
A is not rocked together with the threading mechanism
16
B in order that the size of the sewing machine M may be prevented from being increased.
The sewing machine M is constructed so that the thread
11
can reliably be passed through the needle eye
12
b
when the thread carrying mechanism
16
A and threading mechanism
16
B are operated while the needle bar
12
is stopped at a predetermined upper stop position and located at the left needle thread position (corresponding to the predetermined position). More specifically, the needle bar
12
is stopped at the upper stop position with the thread cassette
10
detached from the cassette mount
5
in order that the thread
11
may reliably be passed through the needle eye
12
b
. In this state, the thread cassette
10
needs to be attached to the cassette mount
5
and the thread carrying mechanism
16
A and threading mechanism
16
B needs to be operated.
The sewing machine M is provided with a threading limiting mechanism
100
as shown in
FIGS. 12A
,
13
A and
14
. The threading limiting mechanism
100
limits the threading mechanism
16
B so that the threading mechanism is inoperative or the threading mechanism does not draw the thread
11
from the thread cassette
10
in a case where the thread cassette
10
is detached from the cassette mount
5
and thereafter attached to the cassette mount while the machine is disconnected from a power supply (for example, when a power switch (not shown) is intentionally turned off or when a stoppage of power supply occurs due to the falling of a thunderbolt).
The threading limiting mechanism
100
includes a holding mechanism
101
holding the moving member
92
at a standby position where the threading mechanism
16
B is inoperative even when the moving member
92
is thrust by the thread cassette
10
being attached to the cassette mount
5
thereby to be moved. The holding mechanism
101
includes a stopper
102
engaging the moving member
92
located at the standby position to hold the moving member at the standby position, the pulse motor
44
switching between an engagement position (see
FIG. 12A
) where the stopper
102
engages the moving member
92
and a non-engagement position (see
FIG. 13A
) where the stopper
102
is disallowed to engage the moving member
92
, and a control device
110
controlling the pulse motor
44
.
The stopper
102
is a vertically elongate link-like member and is provided near the front of the cam member
46
. The stopper
102
has an upper end with a support
102
c
extending rearward. The support
102
c
is mounted on a frame disposed in the rear of the stopper
102
so as to pivot about an axis extending in a longitudinal axis. The stopper
102
has a lower end with a follower
102
b
extending rearward to be engaged with the cam groove
46
b
of the cam member
46
disposed in the rear of the stopper
102
. The stopper
102
further includes an engagement pin
102
a
provided on a lengthwise central portion thereof. The engagement pin
102
a
extends forward to be engageable with the rear (an engaged portion
92
e
) of the moving member
92
disposed in front of the stopper
102
.
Referring to
FIGS. 18A and 18B
, the moving member
92
includes a vertical wall
92
a
and upper and lower horizontal strips
92
b
and
92
c
both extending rightward from the vertical wall. A guide shaft
91
extends through the horizontal strips
92
b
and
92
c
so as to be slid. A right front portion of the horizontal strip
92
c
relative to the guide shaft
91
serves as a thrust portion
92
d
thrust by the thread cassette
10
attached to the cassette mount
5
. A rear portion of the horizontal strip
92
c
relative to the guide shaft
91
serves as the engaged portion
92
e
with which the engagement pin
102
a
is engageable. Furthermore, the horizontal strip
92
c
has a centrally located extended portion
92
g
with a rear end located in front of the engaged portion
92
e.
The pulse motor
44
serves as a component of the needle bar rocking mechanism
18
to rock the needle bar
12
and as a drive source for opening and closing the thread tension discs
40
and
41
. Thus, the pulse motor
44
serves for three mechanisms.
The cam groove
46
b
of the cam member
46
is shaped so that the stopper
102
is located at the non-engagement position and the thread tension discs
40
and
41
are open when the needle bar
12
is at the left needle thread position. The cam groove
46
b
of the cam member
46
is further shaped so that the stopper
102
is located at the engagement position and the thread tension discs
41
and
42
are closed when the needle bar
12
is located at a position other than the left needle thread position.
The control system of the sewing machine M will be described. Referring to
FIG. 19
, the sewing machine M includes a control device
110
having CPU
110
a
, ROM
110
b
, RAM
110
c
, an input interface
110
d
and an output interface
110
e
. To the input interface
110
d
are electrically connected operating switches
6
, the touch panel
8
, spindle angle sensor
111
, and cassette detecting switch
112
. To the output interface
110
e
are electrically connected drive circuits
114
a
to
114
d
driving the sewing machine motor
9
, pulse motor
44
, liquid crystal display
7
and lamps
113
respectively.
The cassette detecting switch
112
detects the thread cassette
10
attached to the cassette mount
5
and comprises a limit switch, for example. The cassette detecting switch
112
is disposed near the lower end of the cassette mount
5
and turned on when the thread cassette
10
is attached to the cassette mount
5
and turned off when the thread cassette
10
is detached or slightly lifted up from the cassette mount
5
.
ROM
110
b
stores a control program for the sewing machine M as shown in FIG.
20
. The control program includes a sewing control program for the sewing operation, a cassette attachment and detachment control program for attaching and detaching the thread cassette
10
to and from the cassette mount
5
, a display control program for displaying various pieces of information on the liquid crystal display
7
, etc.
The following is a brief description of control carried out by the control device
110
on the basis of the cassette attachment and detachment control program. The control device
110
controls the sewing machine motor
9
and the pulse motor
44
on the basis of the results of detection of the spindle angle sensor
111
, cassette detecting switch
112
and start button
200
. The control device
110
controls the sewing machine motor
9
so that the needle bar
12
is automatically moved to the upper stop position when the cassette detecting switch
112
is turned off during detachment of the thread cassette
10
from the cassette mount
5
. The control device
110
further controls the pulse motor
44
so that the cam member
46
is turned to the position as shown in
FIGS. 13A and 13B
and the needle bar
12
is moved to the left needle position, thereby opening the thread tension discs
41
and
42
.
The sewing machine M operates as follows. The control device
110
controls the sewing machine motor
9
and pulse motor
44
when the thread cassette
10
is detached from the cassette mount
5
under the condition where electric power is being supplied to the sewing machine M. Consequently, the needle bar vertically moving mechanism
18
and the needle bar rocking mechanism
19
are operated so that the needle bar
12
is moved to the upper stop position and the left needle position (the predetermined position) Accordingly, when the thread cassette
10
is subsequently attached to the cassette mount
5
, the threading mechanism
16
B is operated so that the thread
11
drawn from the thread cassette
10
is automatically passed through the needle eye
12
b
. In other words, the needle eye
12
b
is moved to a predetermined threading position prior to detachment of the thread cassette
10
.
On the other hand, the sewing machine motor
9
and the pulse motor
44
(and accordingly, the needle bar vertically moving mechanism
18
and the needle bar rocking mechanism
19
) are inoperative when the sewing machine M is shut off from the power supply. Accordingly, the needle bar
12
cannot automatically be moved to the predetermined threading position even if when the thread cassette
10
has been detached from the cassette mount
5
during shutoff of the sewing machine M from the power supply. In some cases, the thread cassette
10
is then detached from the cassette mount
5
during the aforesaid shutoff, and the thread cassette
10
is re-attached to the cassette mount
5
after the needle bar
12
has been stopped at a position other than the predetermined threading position.
In the conventional sewing machines, as described above, the threading mechanism is operated in synchronization with attachment of the thread cassette
10
even when the thread cassette
10
is attached to the cassette mount
5
under the condition where the needle bar
12
is stopped at a position other than the predetermined threading position. In this case, however, since the needle bar
12
is not stopped at the predetermined position, passing the thread through the needle eye tends to fail, and the threading mechanism
16
B tends to interfere with the thread carrying mechanism
16
A or the like such that the threading mechanism
16
B, the thread carrying mechanism
16
A and the like would be damaged.
On the other hand, in the embodiment, the pulse motor
44
is driven to operate the cam member
46
and the like when the thread cassette
10
is attached to the cassette mount
5
and the detaching operation member
60
is subsequently operated after finish of the sewing during supply of electric power to the sewing machine M. Consequently, the stopper
102
is switched from the engagement position to the non-engagement position as shown in
FIGS. 13A
,
21
C and
21
D.
When the stopper
102
is located at the non-engagement position, the engagement pin
102
a
of the stopper is located above the engaged portion
92
e
, on the right of the rightmost end
92
f
(shown by broken line in
FIG. 21C
) of the engaged portion
92
e
and in the rear of the extended portion
92
g
. Accordingly, the engagement pin
102
a
is spaced away from the moving portion
92
such that the moving portion is released from the holding by the engagement pin. As a result, the spring force of the extension coil spring
93
raises the moving member
92
to the aforesaid initial position. When reaching the initial position, the moving member
92
is coupled to the hook mechanism section
84
, whereby both moving member and hook mechanism section can be moved vertically together. In other words, the threading mechanism
16
B is rendered operative with attachment of the thread cassette
10
to the cassette mount
5
.
Subsequently, the thread cassette
10
is attached to the cassette mount
5
during supply of electric power to the sewing machine M. Upon operation of the start button
200
for start of the sewing, the pulse motor
44
is driven since the thread needs to be tensioned for the sewing. Consequently, the thread is tensioned by the thread tensioning mechanism
14
. With rotation of the pulse motor
44
for the thread tensioning, the cam member
46
is operated so that the stopper
102
is switched from the non-engagement position to the engagement position as shown in
FIGS. 12A
,
21
A and
21
B. The stopper
102
is maintained at the engagement position while the thread is tensioned. The thread is not released from the tensioned state when the sewing has been completed. Accordingly, the thread tensioning mechanism
14
is still ready for tensioning the thread and the stopper
102
is located at the engagement position.
When the stopper
102
is located at the engagement position, the engagement pin
102
a
of the stopper is located right above the engaged portion
92
e
, on the left of the rightmost end
92
f
(shown by broken line in
FIG. 21A
) of the engaged portion
92
e
. Accordingly, in a case where the thread cassette
10
has been detached from the cassette mount
5
, the engaged portion
92
e
abuts the underside of the engagement pin
102
a
, whereupon the moving member
92
cannot reach the upper stop position even when the spring force of the extension coil spring
93
raises the moving member
92
. Since the moving member
92
is held by the engagement pin
102
a
, the moving member
92
remains spaced away from the hook mechanism section
84
.
The sewing machine M is shut off from the power supply while the thread cassette
10
is attached to the cassette mount and the thread is tensioned by the thread tension determining mechanism
14
. When the detaching operation member
60
is operated during shutoff of the sewing machine M from the power supply, the thread cassette
10
is detached from the cassette mount
5
. The pulse motor
44
cannot be operated since the sewing machine M has been shut off from the power supply. In other words, the stopper
102
cannot be switched from the engagement position to the non-engagement position by the pulse motor
44
as shown in
FIGS. 13A
,
21
C and
21
D. Furthermore, since the moving member
92
and the hook mechanism section
84
are separated away from each other, the hook mechanism section is not descended even when the thread cassette
10
is attached to the cassette mount
5
.
The needle bar vertically moving mechanism
18
and the needle bar rocking mechanism
19
cannot be operated by the sewing machine motor
9
and the pulse motor
44
since the sewing machine M is shut off from the power supply. On the other hand, even in a case where the moving member
92
and the hook mechanism section
84
are separated away from each other, the thread carrying mechanism
16
A is operated when the thread cassette
10
is attached to the cassette mount
5
. As a result, a part of the mechanism is descended near the needle eye
12
b
. The needle eye
12
b
is not always located at a position suitable for thread passing when the sewing machine M is shut off from the power supply and accordingly stopped. Furthermore, even when the needle eye
12
b
is located at a position suitable for the thread passing immediately after shutoff from power supply, a hand pulley (not shown) provided on the sewing machine M is operated so that the location of the needle eye
12
b
is manually changed vertically. As a result, the position of the needle eye
12
b
would be unsuitable for the thread passing.
In the sewing machine M of the embodiment, however, the thread cassette
10
is detached from the cassette mount
5
when the sewing machine is shut off from the power supply. Thereafter, when the thread cassette
10
is attached to the cassette mount
5
during the shutoff, the threading limiting mechanism
100
limits the threading mechanism so that the threading mechanism is inoperative. Thus, the threading mechanism
16
B is inoperative even when the thread cassette
10
is erroneously attached to the cassette mount
5
although the needle bar
12
is not stopped at the predetermined position. Consequently, the threading mechanism
16
B and other mechanisms or components can be prevented from being damaged.
In the above-described construction of the sewing machine M, the threading mechanism
16
B is operated by thrusting the moving member
92
from the initial position by the thread cassette
10
attached to the cassette mount
5
. However, since the moving member
92
is held at the standby position by the holding mechanism
101
of the threading limiting mechanism
100
, the threading mechanism
16
B can be rendered inoperative even when the moving member
92
is thrust by the thread cassette
10
attached to the cassette mount
5
. Consequently, since the thread
11
is not drawn from the thread cassette
10
by the threading mechanism
16
B, the thread
11
can be prevented from being rewound and accordingly, the usability of the sewing machine can be improved.
The holding mechanism
101
includes the stopper
102
, pulse motor
44
and control device
110
. The control device
110
controls the pulse motor
44
so that the stopper
102
is switched between the engagement position and the non-engagement position. In this case, the stopper
102
, when located at the engagement position, engages the moving member
92
located at the standby position, whereupon the moving member
92
can be maintained at the standby position under the condition where electric power is being supplied to the sewing machine M. When the stopper
102
is located at the non-engagement position, the moving member
92
can be returned to the initial position.
The stopper
102
is switched by the pulse motor
44
between the engagement position and the non-engagement position. Furthermore, the needle bar
12
is rocked via the needle bar rocking mechanism
19
. Consequently, the number of actuators can be reduced. This is advantageous for synchronous operation of various mechanisms. Furthermore, the stopper
102
is located at the engagement position when the needle bar
12
is located at a position other than the foregoing predetermined position. Consequently, the moving member
92
can be maintained at the standby position.
The pulse motor
44
serves to switch the stopper
102
between the engagement and non-engagement positions, to rock the needle bar
12
by means of the needle bar rocking mechanism
19
and to open and close the thread tension discs
41
and
42
tensioning the thread
11
drawn from the thread cassette
10
. Consequently, the number of actuators can further be reduced. This is further advantageous for synchronous operations of the mechanisms.
Modified forms of the foregoing embodiment will now be described. The thread cassette
10
is a mere example and accordingly, the thread cassette should not be limited to the one including a supply of thread comprising a thread spool or the like on which a thread is wound up. The thread cassette may comprise a storing section in which a lump of thread serving as a supply of thread is stored. Furthermore, at least one of walls covering the thread storing section may be eliminated and a thread spool may be held on a holding section such as a spool pin.
The moving member
92
can be moved downward to some extent by the thread cassette
10
attached to the cassette mount
5
whether or not the sewing machine M is connected to the power supply. However, the moving member
92
may be disallowed to be moved downward when the sewing machine M is shut off from the power supply. Furthermore, it is considered that an excessively large force is applied in the abutment of the thread cassette
10
against the moving member
92
. However, when the thread cassette
10
abuts the moving member
92
such that the moving member is moved downward against the urging force of the spring
93
, a buffering or shock absorbing function is obtained for prevention of damage in the moving member
92
and thread cassette
10
.
A stopper mechanism may be provided on a movement path of the thread cassette
10
for preventing downward movement of the thread cassette in order that the moving member may be prevented from being thrust by the thread cassette when the thread cassette is attached to the cassette mount during the shutoff of the sewing machine from the power supply. The stopper mechanism may comprise a solenoid actuator, for example. The solenoid actuator may be controlled so that the stopper is retreated from the movement path while electric power is being supplied to the sewing machine M and so that the stopper is protruded from the movement path while the sewing machine M is shut off from the power supply. Consequently, the thread
11
can be prevented from being drawn uselessly by the sewing machine M (the thread carrying mechanism
16
A, threading mechanism
16
B, thread tensioning mechanism
14
and needle thread take-up lever
3
).
The thread carrying mechanism
16
A is operated even when the thread cassette
10
is attached to the cassette mount
5
under the condition where the moving member
92
and the hook mechanism section
84
are spaced away from each other. As a result, a part of the thread carrying mechanism
16
A is descended near the needle eye
12
b
. However, a second stopper such as the stopper
102
for the moving member
92
may be provided to render the thread carrying mechanism
16
A inoperative even when the thread cassette
10
is attached to the cassette mount
5
during shutoff of the sewing machine from the power supply. Furthermore, the thread carrying mechanism
16
A may be provided with an electric motor rendering the mechanism inoperative even when the thread cassette
10
is attached to the cassette mount
5
during shutoff of the sewing machine from the power supply. Thus, the thread
11
can be prevented from being drawn uselessly when the thread carrying mechanism
16
A is constructed so as to be rendered inoperative even when the thread cassette
10
is attached to the cassette mount
5
during the shutoff. Consequently, the usability of the sewing machine M can be improved. Additionally, the threading limiting mechanism
100
may be provided in a sewing apparatus which includes the threading mechanism
16
B but does not include the thread carrying mechanism
16
A.
The foregoing description and drawings are merely illustrative of the principles of the present invention and are not to be construed in a limiting sense. Various changes and modifications will become apparent to those of ordinary skill in the art. All such changes and modifications are seen to fall within the scope of the invention as defined by the appended claims.
Claims
- 1. A sewing apparatus comprising:a needle bar on which a sewing needle is mounted; a needle bar vertically moving mechanism vertically moving the needle bar; a thread cassette having a thread accommodating section accommodating a supply of thread; a cassette mount to which the thread cassette is detachably attached; a threading mechanism operated in synchronization with attachment of the thread cassette to the cassette mount when the needle bar is stopped at a predetermined position, the threading mechanism passing the thread drawn from the thread cassette through an eye of the needle mounted on the needle bar; and a threading limiting unit limiting the threading mechanism so that the threading mechanism is inoperative in a case where the thread cassette is attached to the cassette mount when the apparatus is disconnected from a power supply.
- 2. A sewing apparatus according to claim 1, further comprising a needle bar rocking mechanism for rocking the needle bar and a needle bar movement controlling unit controlling the needle bar vertically moving mechanism and the needle bar rocking mechanism so that the needle bar is moved to the predetermined position in a case where the thread cassette has been detached from the cassette mount while electric power is being supplied to the apparatus.
- 3. A sewing apparatus according to claim 1, further comprising a needle bar movement controlling unit controlling the needle bar vertically moving mechanism so that the needle bar is moved to the predetermined position in a case where the thread cassette has been detached from the cassette mount while electric power is being supplied to the apparatus.
- 4. A sewing apparatus according to claim 1, wherein the threading mechanism includes a moving member provided on the cassette mount, the moving member being thrust by the thread cassette attached to the cassette mount thereby to be moved from an initial position so that the threading mechanism is operated, and the threading mechanism includes a holding unit holding the moving member at a standby position where the threading mechanism is inoperative even when the moving member is thrust by the thread cassette being attached to the cassette mount.
- 5. A sewing apparatus according to claim 4, wherein the holding unit includes a stopper engaging the moving member located at the standby position to hold the moving member at the standby position, an actuator switching between an engagement position where the stopper engages the moving member and a non-engagement position where the stopper is disallowed to engage the moving member, and a control unit controlling the actuator.
- 6. A sewing apparatus according to claim 5, wherein the actuator comprises a pulse motor provided in the needle bar vertically moving mechanism for rocking the needle bar, and the threading limiting unit limits the threading mechanism so that the stopper is located at the non-engagement position when the needle bar is located at the predetermined position and so that the stopper is located at the engagement position when the needle bar is located at a position other than the predetermined position.
- 7. A sewing apparatus according to claim 6, wherein the pulse motor also serves to open and close a thread tension disc applying a tension to the thread drawn from the thread cassette, and the thread tension disc is opened when the needle bar is located at the predetermined position and closed when the needle bar is located at a position other than the predetermined position.
- 8. A sewing apparatus comprising:a needle bar on which a sewing needle is mounted; a needle bar vertically moving mechanism vertically moving the needle bar; a thread cassette having a thread accommodating section accommodating a supply of thread; a cassette mount to which the thread cassette is detachably attached; a thread carrying mechanism operated in synchronization with attachment of the thread cassette to the cassette mount when the needle bar is stopped at the predetermined position, thereby carrying the thread from the thread cassette to a position near an eye of the needle mounted on the needle bar; a threading mechanism operated in synchronization with attachment of the thread cassette to the cassette mount when the needle bar is stopped at the predetermined position, the threading mechanism passing the thread drawn from the thread cassette through the needle eye; and a limiting unit limiting the threading mechanism and the thread carrying mechanism so that both the threading mechanism and the thread carrying mechanism are inoperative in a case where the thread cassette is attached to the cassette mount when the apparatus is disconnected from a power supply.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2002-252528 |
Aug 2002 |
JP |
|
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5086718 |
Ogawa |
Feb 1992 |
A |
5092257 |
Ogawa |
Mar 1992 |
A |
Foreign Referenced Citations (2)
Number |
Date |
Country |
2002-91558 |
Mar 2002 |
JP |
2002-225245 |
Aug 2002 |
JP |