JPH0140637B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a safety device for a buttonhole sewing machine, which is a type of cycle sewing machine.

Prior Art In a conventional buttonhole sewing machine, at the end of one buttonhole sewing cycle, the rotation of the main shaft is brought to a low speed drive state by the action of the deceleration cam piece on the feed cam, and the cutter with the cutter is rotated at a low speed. By fitting an engaging arm connected to the rod via a swinging lever and a drive arm that swings in conjunction with the main shaft, the cutter rod and the main shaft are operated in conjunction with each other to perform sewing. After the center part of the finished buttonhole stitch is cut out, the rotation of the main shaft is stopped based on the action of the stop cam piece on the feed cam. However, the mounting positions of the stop cam piece and the deceleration cam piece on the feed cam may be changed to adjust the deceleration timing and stop timing of the main shaft. Due to this adjustment, if the activation timing of the deceleration cam piece is delayed, the fitting part of the engagement arm and the drive arm may fit together when the main shaft is in a high-speed drive state; At times, there is a risk that these may break due to a large impact, and there is also a risk that fitting may not be successful because the drive arm swings at high speed. In addition, when adjusting each cam piece, the main shaft is stopped, but if the main shaft and cutter bar remain connected at this time, the cutter will not move at the beginning of the next sewing cycle. There is also the problem that the workpiece cloth may be cut if it is operated erroneously.

Purpose This invention was made to eliminate the above-mentioned defects, and its purpose is to prevent the main shaft and cutter rod from being connected in the high-speed driving state and cut-off state, and to prevent the main shaft from being connected to the cutter rod in the low-speed driving state. By fitting the driving arm and the engaging arm at
It is an object of the present invention to provide a safety device for a sewing machine that can reduce the impact force during this fitting to prevent these damages and also ensure the fitting.

Embodiment An embodiment embodying the present invention will be described below with reference to FIGS. 1 to 5. A main shaft 1 is rotatably supported on a sewing machine frame, and a fixed pulley 2 and a floating pulley are mounted on one end of the main shaft 1. 3 is provided.
In addition, a motor (not shown) is attached to the sewing machine frame.
A high-speed pulley 4 and a low-speed pulley 5 are provided, which are rotated at high and low speeds by, respectively. The fixed pulley 2 or the floating pulley 3 and the high speed pulley 4
Alternatively, a belt 6 is hung between the low speed pulley 5 and one end of the belt 6 is connected to the fixed pulley 2 and the floating pulley 3, and the other end is connected to the high speed pulley 4 and the low speed pulley 5.
It is designed so that each can be replaced with the other.

A clutch lever 7 is rotatably supported at approximately the center of the sewing machine frame, and is biased to rotate counterclockwise in FIG. 1 by a tension spring 8. A protrusion 9 that can be engaged with the side surface of the fixed pulley 2 is formed at the tip of the lever 7, and when engaged, the main shaft 1 is stopped at a fixed position. Further, one end of the belt 6 is connected to a fixed pulley 2 on one side of the lever 7.
A belt changing arm 10 for changing the belt between the belt and the idler pulley 3 is provided in a protruding manner. Further, on one side of this lever 7, there is a pair of engaging parts 11a, 1 for holding the sewing machine in a low-speed operating state and a high-speed operating state.
A projecting piece 11 having a diameter of 1b is provided in a protruding manner.

An operating arm 12 is rotatably supported on the sewing machine frame at approximately the center between the fixed pulley 2 and the high-speed pulley 4, and is biased to rotate counterclockwise in FIG. 1 by a tension spring 13. There is. One end of this operating arm 12 is provided with an engaging protrusion 14 that can engage with the protruding piece 11, and the other end of the actuating arm 12 is provided with the other end of the belt 6, which is hooked between the high speed pulley 4 and the low speed pulley 5. A belt replacement part 15 for changing the belt is provided. A hook-shaped actuating protrusion 1 is provided at the tip of the arm protruding near the engaging protrusion 14 of the actuating arm 12.
6 is formed. Further, an intermediate lever 17 is rotatably supported near the lower end of the clutch lever 7, one end of which is connected to an operating pedal 19 for starting via a connecting chain 18, and a protruding portion of the other end is connected to the clutch lever 7. It is adapted to be able to engage with the lower end of the lever 7.

When the clutch lever 7 is rotated clockwise in FIG. 1 via the intermediate lever 17 by depressing the starting operation pedal 19, the protrusion 9 is disengaged from the fixed pulley 2, and the clutch lever 7 is rotated clockwise in FIG. The protruding piece 11 is the engaging protrusion 14 of the actuating arm 12
depart from. As a result, the actuating arm 12 is allowed to rotate counterclockwise in FIG. 1 based on the spring force of the tension spring 13, and the engaging protrusion 14
It is sequentially engaged with the first engaging portion 11a, 11b. Then, the engagement protrusion 14 is connected to the low-speed engagement portion 1 of the protrusion 11.
1a, the belt 6 is hung between the fixed pulley 2 and the low-speed pulley 5 by the cooperation of the belt-hanging arm 10 and the belt-hanging part 15, and the main shaft 1 is rotated at a low speed. . Further, the engagement protrusion 14
When engaged with the high-speed engagement portion 11b of the protruding piece 14, the belt 6 is hung between the fixed pulley 2 and the high-speed pulley 4, and the main shaft 1 is rotated at high speed. In addition, the fixed pulley 2, the floating pulley 3, and the belt 6
and the operating arm 12 constitute a clutch mechanism.

As shown in FIGS. 2 and 3, in the front part of the sewing machine frame, a feed cam 20 having a cam part (not shown) at the center of the front surface for controlling the feed of the workpiece cloth is mounted on a uniaxial line perpendicular to the main shaft 1. It is rotatably supported around the main shaft 1, and is rotated once in the counterclockwise direction in FIG. 2 for each buttonhole sewing cycle as the main shaft 1 rotates. This feed cam 2
A deceleration cam piece 21 and a stop cam piece 22 are positioned at a predetermined interval on the front surface of the outer peripheral edge of the feed cam 20 through arc-shaped elongated holes and adjusted in the circumferential direction of the feed cam 20 by two screws 23 and 24. installed as possible. Each of the cam pieces 21 and 22 has a control cam surface 2 that can engage with the actuating protrusion 16 of the actuating arm 12.
5 and 26 are formed, respectively.

During high-speed rotation of the main shaft 1, when the control cam surface 25 of the deceleration cam piece 21 is engaged with the actuating protrusion 16 of the actuating arm 12 as the feed cam 20 rotates, the actuating arm 12 is activated by the tension spring. It is rotated slightly clockwise in FIG. 1 against the spring force 13. Then, the rotational speed of the main shaft 1 is switched to a low speed state based on the engagement protrusion 14 being engaged with the engagement part 11a after being disengaged from the engagement part 11b of the protrusion 11. Thereafter, when the control cam surface 26 of the stop cam piece 22 is engaged with the actuating protrusion 16, the actuating arm 12 is further rotated in the clockwise direction, and the engaging protrusion 14 is disengaged from the engaging part 11a. Based on this, the rotation of the main shaft 1 is stopped.

As shown in FIG. 5, a drive arm 27 is swingably supported at its base end on the sewing machine frame adjacent to the main shaft 1. In addition, an eccentric cam 2 is attached to the main shaft 1.
8 is fixed and the drive arm 27 is rotated through the eccentric cam 28 and cam follower 29 while the main shaft 1 is rotated twice.
It is designed to move once. 2nd, 3rd,
As shown in Figure 5, a cutter rod 30 extending vertically is supported on the sewing machine frame so as to be movable up and down, a cutter 32 is attached to the lower end of the rod via a mounting member 31, and a shock absorbing rod is attached to the upper end. A rubber piece 33 is fitted. The rubber piece 33
The cutter rod 3 is attached to the sewing machine frame above the
A stopper 34 for regulating the upward movement position of 0 is screwed so that the position can be adjusted. A connecting member 3 is installed approximately in the center of this cutter rod 30 with a screw 35a.
5 is fixed, and a pin 36 is provided protruding from one side thereof.

A swing lever 38 is swingably supported by an intermediate cylindrical portion 39 on a support shaft 37 provided on the sewing machine frame between the cutter rod 30 and the feed cam 20, and a pin 40 is attached to one end of the swing lever 38. It is installed protrudingly. The pin 40 on this swing lever 38
A connecting piece 41 is provided between the connecting piece 41 and the pin 36 on the connecting member 35, and the swinging lever 38 is connected to the cutter rod 3 via the connecting piece 41 and the connecting member 35.
Connected to 0. In addition, this swing lever 38
is biased by a tension spring 42 to swing clockwise in FIG. It is held at an upper position in line with the stopper 34.

A shaft 43 provided at the other end of the swing lever 38
In a, an engaging arm 43 having a substantially L-shape in front view is supported at its base end so as to be rotatable between an inactive position shown by a solid line in FIG. 2 and an active position shown by a chain line in the same figure. At its tip, an engagement recess 44 that can be engaged with the tip of the drive arm 27 is provided, and an engagement pin 45 is provided in a protruding manner. An extending arm portion 46 is integrally formed at the base end of the engaging arm 43 and extends laterally in a substantially arc shape. Further, this engaging arm 43 is biased to rotate clockwise in FIG. 2 by a tension spring 47 as biasing means. When the engagement arm 43 is placed in the operating position and the engagement recess 44 is engaged with the drive arm 27, the swing lever 38 is moved through the engagement arm 43 as the drive arm 27 swings. is swung, and the cutter rod 30 is moved up and down.

As shown in FIGS. 2 to 4, an operating shaft 49 is supported by a pair of support pieces 49a and metal 48 adjacent to the extending arm portion 46 of the engaging arm 43 and fixed to the sewing machine frame so as to be movable back and forth. and a compression spring 5 interposed between the operating shaft 49 and the rear support piece 49a.
0 to move forward, and the forward movement position is restricted by the front support piece 49a. A cylindrical collar 51 is fixed approximately at the center of the operating shaft 49 with a screw 51a, and between the fixed collar 51 and the metal 48, the operating shaft 49 has a flange 52a with a larger diameter than the fixed collar 51. A movable collar 52 serving as a stopper means is movably inserted therethrough. The movable collar 52 is urged forward by a compression spring 53 interposed between the movable collar 52 and the metal 48, and its flange 52a is always engaged with the fixed collar 51 as shown in FIG. are combined.

The stop cam piece 2 is mounted on the rear surface of the feed cam 20 so as to be able to engage with the front end of the operating shaft 49.
A control cam piece 54 is fixed at a position facing 2, and the control cam piece 54 has an inclined cam surface 54a for engaging the front end of the operating shaft 49 and moving the operating shaft 49 rearward; A flat surface 54b is formed for arranging the operating shaft 49 at a rearward movement position. When the control cam piece 54 is in a position away from the operating shaft 49 while the feed cam 20 is rotating, as shown in FIG.
Based on the spring force of the compression springs 50 and 53, the operating shaft 4
9 and the movable collar 52 are disposed at the front position, and in this state, the extending arm portion 4 of the engaging arm 43
6 is engaged with the outer periphery of the flange 52a of the movable collar 52, and its engaging arm 43 is placed and held in the non-active position shown by the solid line in FIG.

Furthermore, as the feed cam 20 rotates at the end of one sewing cycle, the control cam piece 54 is moved onto the actuating shaft 49 just before the control cam surface 26 of the stop cam piece 22 engages with the actuating protrusion 16 of the actuating arm 12. When engaged, the operating shaft 49 and moving collar 52 are integrally moved rearward along the inclined cam surface 54a against the spring force of the compression springs 50, 53. As a result, the extending arm portion 46 of the engaging arm 43 is connected to the flange 5.
2a, the engaging arm 43 is rotated clockwise in FIG. .

Subsequently, after the flat surface 54b is engaged with the operating shaft 49 and held in the backward moving position, when the control cam piece 54 is disengaged from the operating shaft 49, the fourth
As shown in the figure, the moving collar 52 is moved forward based on the spring force of the compression spring 53, and the flange 5
The front side of the arm 2a is held engaged with the rear side of the extending arm 46. On the other hand, based on the spring force of the compression spring 50, the fixed collar 51 along with the operating shaft 49
is moved to the forward position, so the moving collar 52
A gap is formed between and the fixed collar 51.
Thereby, the engaging arm 43 is further rotated clockwise in FIG. The engaging arm 43 is placed in the operative position shown in dashed lines in FIG.

As shown in FIGS. 2, 3, and 5, a release lever 55 is rotatably supported at the base end of the support shaft 37, and a bifurcated portion 56 and a forked portion 56 extending upwardly extend from the base end of the release lever 55. An extending piece 57 that can be engaged with the engagement pin 45 of the joint arm 43 is formed. When the release lever 55 is rotated counterclockwise in FIG. 2 with the engagement arm 43 placed in the operating position shown by the chain line in FIG. 2, the extending piece 57 is engaged. pin 4
5, the engaging arm 43 is rotated counterclockwise in the figure and placed in the non-operating position shown by the solid line in the figure.

A tri-arm-shaped operating lever 58 is rotatably supported on the sewing machine frame at approximately the center between the support shaft 37 and the operating shaft 49, and engages with the control cam surface 26 of the stop cam piece 22. As shown in FIG. second and third arm portions 60 of the actuation lever 58;
Connecting pins 60a and 61a are respectively protrudingly provided on the second arm portion 61, and the pin 60a on the second arm portion 60 is engaged with the forked portion 56 of the release lever 55. The actuating lever 58 is biased to rotate counterclockwise in FIG. 2 by a tension spring 62, and the release lever 55 is biased to rotate clockwise in the diagram via the connecting pin 60a and the forked portion 56. Forced.

As shown in FIGS. 1 and 2, a connecting rod 63 is disposed between the actuating lever 58 and the actuating arm 12, one end of which is rotatably connected to the actuating arm 12, and a connecting rod 63 formed at the other end. A connecting pin 61a of the third arm portion 61 is engaged with the elongated hole 63a.
When the operating arm 12 is placed at the chain line position in FIG. 2 during high-speed operation of the sewing machine, it is engaged via the connecting rod 63, the connecting pin 61a, the operating lever 58, the connecting pin 60a, the release lever 55, etc. Arm 43 is placed in the inactive position shown in solid lines in FIG. Further, the operating arm 12 is rotated clockwise in FIGS. 1 and 2 based on the engagement with the deceleration cam piece 21 and the stop cam piece 22, and the connecting rod 63 is moved to the right in FIG. At times, the operating lever 58 is rotated counterclockwise in FIG. 2 by the spring force of the tension spring 62, and the release lever 55 is rotated clockwise via the connecting pin 60a and the fork 56.

As shown in FIGS. 2 and 3, the actuation lever 58
A shaft 64 extending back and forth is rotatably supported on the sewing machine frame at the rear of the sewing machine frame, and a release arm 65 having a pin 65a that can be engaged with the side edge of the third arm portion 61 of the operating lever 58 is fixed to the front end of the shaft 64. has been done.
A connecting rod 67 is rotatably connected at one end to the end of the connecting member 66 fixed to the rear end of the shaft 64, and the other end of the connecting rod 67 is rotatably connected to the clutch lever 7. possible to be connected. During high-speed operation of the sewing machine, the clutch lever 7 is rotated more clockwise than the state shown in FIG. The connecting member 66, shaft 64, and release arm 65 are in a state of being rotated counterclockwise, and the pin 6 of the release arm 65 is rotated counterclockwise.
5a is disposed at a position where it separates from the third arm portion 61. Further, when the clutch lever 7 is rotated counterclockwise in FIG. 1 to stop the sewing machine, the release arm 65 is rotated clockwise in FIG. 2 via the connecting rod 67, the connecting member 66, and the shaft 64. rotated,
The pin 65a is engaged with the third arm portion 61, and the operating lever 58 is placed in the position shown in FIG. As a result, the engagement arm 43 is disposed via the release lever 55 and the engagement pin 45 to the inactive position shown by the solid line in FIG.

Note that the operating lever 58, shaft 64, and release arm 6
5, a connecting rod 67, and the like constitute a transmission means.

Next, the operation of the sewing machine configured as described above will be explained. Now, FIG. 1 shows the sewing machine in a stopped state. In this state, start operation pedal 1
9, the connecting chain 18 and intermediate lever 17
The clutch lever 7 is rotated clockwise in FIG. 1 against the spring force of the tension spring 8, and its protrusion 9 is disengaged from the fixed pulley 2. In addition, one end of the belt 6 is connected to the idle pulley 3 by the belt replacement arm 10.
At the same time, the operating arm 12 is rotated counterclockwise in FIG. 1 based on the spring force of the tension spring 13. First, the engagement protrusion 14 of the operating arm 12 is engaged with the low-speed engagement part 11a of the protrusion 11, and with the other end of the belt 6 hanging around the low-speed pulley 5, the low-speed The main shaft 1 is rotated at low speed via the pulley 5, belt 6, and fixed pulley 2.

After that, the engagement protrusion 14 of the operating arm 12 is engaged with the high-speed engagement part 11b, and the other end of the belt 6 is switched from the low-speed pulley 5 to the high-speed pulley 4 by the belt switching section 15. The main shaft 1 is rotated at high speed. As the main shaft 1 rotates, the feed cam 20 is rotated counterclockwise in FIG.
One sewing cycle of buttonholing can be performed during one rotation.

While the main shaft 1 is rotating, the second and fifth
As shown in the figure, the drive arm 2
7 is moved up and down between an upper position shown by a solid line in FIG. 2 and a lower position shown by a solid line in the figure. Also,
As shown in FIGS. 2 and 3, during high-speed operation of the sewing machine, the operating shaft 49 and the fixed collar 51 are placed in the forward regulating position based on the spring force of the compression spring 50, and the spring force of the compression spring 53 Based on this, the end face of the flange 52a of the moving collar 52
1 is engaged. Then, based on the spring force of the tension spring 47, the end surface of the extending arm portion 46 of the engaging arm 43 is engaged with the outer peripheral edge of the flange 52a of the movable collar 52, and the spring force of the tension spring 42 causes the end face Lever 38, connecting piece 41 and connecting member 3
Since the cutter rod 30 is reliably held in the upper inactive position shown in FIG.

Further, based on the counterclockwise rotation of the actuating arm 12, the extending piece 57 of the release lever 55 is engaged with the engagement pin 45 of the engagement arm 43 via the connecting rod 63 and the actuation lever 58, The engaging arm 43 is held in a non-active position as shown by the solid line in FIG.
Furthermore, based on the clockwise rotation of the clutch lever 7, the release arm 65 is rotated counterclockwise via the connecting rod 67, the connecting member 66, and the shaft 64, and the pin 65a is It is held apart from the third arm portion 61.

In this state, as the feed cam 20 rotates,
When the control cam surface 25 of the deceleration cam piece 21 is engaged with the operating protrusion 16 of the actuating arm 12 at the end of cycle sewing, the actuating arm 12 moves as shown in FIGS. 1 and 2 according to the cam shape of the control cam surface 25. The other end of the belt 6 is changed from the high-speed pulley 4 to the low-speed pulley 5 via the belt changing section 15, and the main shaft 1 is rotated at a low speed. Further, based on the return rotation of the operating arm 12, the connecting rod 63 is moved to the right in FIG. 2, and the spring force of the tension spring 62 causes the operating lever 58 to be slightly rotated counterclockwise in FIG. The third arm portion 61 is moved to the pen 65a.
At the same time, the release lever 55 is rotated clockwise via the connecting pin 60a of the second arm portion 60 and the two-pronged portion 56 of the release lever 55, and the extending piece 57 of the release lever 55 is engaged with the engagement arm 43. It separates from the engagement pin 45 of.

Thereafter, as the feed cam 20 rotates, the control cam piece 54 is engaged with the front end of the operating shaft 49, and the compression springs 50, 53 are moved in accordance with the shape of the inclined cam surface 54a.
The operating shaft 49, fixed collar 51, and movable collar 52 are integrally moved rearward against the spring force of The engaging arm 43 is rotated clockwise in FIG. 2 by the spring force of the tension spring 47. As is clear from FIGS. 2 to 4, the end surface of the engaging arm 46 is engaged with the outer peripheral surface of the fixed collar 51, and the engaging arm 43 is inactive as shown by solid lines and chain lines in FIG. It is arranged at an intermediate position between the position and the working position.

Thereafter, when the control cam piece 54 is disengaged from the operating shaft 49, the movable collar 52 is slightly returned forward by the spring force of the compression spring 53, as shown in FIG. While engaging with the extending arm 46, the spring force of the compression spring 50 causes the operating shaft 49 and the fixed collar 51 to move back significantly forward, creating a gap between the flange 52a of the movable collar 52 and the fixed collar 51. It is formed. Accordingly, the engaging arm 43 is further rotated clockwise in FIG. 2 and is placed in the operating position shown by the chain line in the same figure. Then, as the drive arm 27 swings,
When the tip is placed in the lower position shown by the solid line in FIG.
4, and the drive arm 27 and the cutter rod 30 are operatively connected via the engagement arm 43, the swing lever 38, and the like. At this time, since the drive arm 27 is in a low-speed operating state, the engagement recess 44 of the engagement arm 43 is reliably fitted into the drive arm 27, and the impact force generated during this fitting is also significant. can be reduced.

In this state, the tip of the drive arm 27 and the engagement arm 43
are integrally moved to the vertical position shown by the chain line in FIG. 2, the swing lever 38 is swung counterclockwise in FIG. 2 against the spring force of the tension spring 42, and the cutter bar 30 moved downward. Therefore, the cutter 30 at the lower end of the cutter rod 30 cuts open the center portion of the buttonhole stitch on the finished work cloth. Additionally, with the upward movement of the engaging arm 43,
Since the extending arm portion 46 is detached from the operating shaft 49, the moving collar 5 is moved by the spring force of the compression spring 53.
2 is moved forward and engaged with the fixed collar 51, and the end surface of the extending arm 46 is moved forward and engaged with the fixed collar 51.
The engagement arm 43 is again engaged with the outer peripheral edge of the flange 52a of FIG.

Thereafter, when the control cam surface 26 of the stop cam piece 22 is engaged with the actuation protrusion 16 of the actuating arm 12, the actuating arm 12 returns to the solid line position in FIG. 1 according to the cam shape of the control cam surface 26. be moved. As a result, the engaging protrusion 14 of the actuating arm 12 is disengaged from the engaging part 11b of the protruding piece 11, and the clutch lever 7 is rotated counterclockwise in FIG. 1 by the spring force of the tension spring 8. One end of the belt 6 is replaced with the idler pulley 3 by the belt replacement arm 10, and the main shaft 1 is stopped at a fixed position by the protrusion 9. Also, in conjunction with this stopping operation, the release arm 65 is rotated clockwise in FIG. Even if the main shaft 1 is stopped before the operative connection between the drive arm 27 and the cutter rod 30 via the engagement arm 43 is released, the rotation of the release arm 65 causes the pin 65a to be stopped.
The actuating lever 58 through engagement with the third arm portion 61
is rotated in the clockwise direction in FIG. The device is securely placed in the inactive position.
Therefore, cutter bar 3 is removed at the beginning of the next sewing cycle.
0 can be prevented from being erroneously activated.

Furthermore, if the main shaft 1 and the cutter rod 30 remain connected when adjusting the sewing machine with the main shaft 1 stopped, the cutter 32 may be erroneously activated at the beginning of the next sewing cycle. In this example, the feed cam 2 is used to cut the work cloth.
0 rotation, the stop cam piece 22 moves the actuating lever 5.
8, the operating lever 5 is engaged with the first arm 59 of the
8 in the clockwise direction in FIG. It cannot be activated accidentally.

In addition, in this embodiment, when adjusting the sewing machine,
Based on the action of the control cam piece 54, etc., the operating shaft 49,
Both collars 51, 52 and the engaging arm 43 are placed in the position shown in FIG. 4, and the engaging recess 44 of the engaging arm 43 is engaged with the drive arm 27 stopped at the lower position in FIG. When the feed cam 20 is manually rotated in this state, the control cam piece 54 and the operating shaft 4
9, the extending arm portion 46 of the engaging arm 43 may be pinched between the collars 51, 52, resulting in a locked state. However, in this embodiment, before the control cam piece 54 and the actuating shaft 49 re-engage, the stop cam piece 22 engages with the first arm portion 59 of the actuating lever 58 as the feed cam 20 rotates. Since the operating lever 58 is rotated clockwise in FIG. 2, the occurrence of the locked state can be prevented.

Effects As detailed above, the present invention has an inactive position in which the fitting portion is engaged with the engaging arm and disengaged from the drive arm, and a non-active position in which the fitting portion is disengaged from the engaging arm and engaged by the action of the stopper means. A release lever is provided on the frame so as to be rotatable between an operating position that allows rotation of the arm toward the driving arm, and a release lever is provided between the release lever and the clutch lever to operate the clutch mechanism. When the clutch lever is placed in a position where the locking state and the high-speed drive state are brought, when the clutch lever is placed in a position where the release lever is moved to the inactive position and the clutch mechanism is brought into the low speed state, By providing a transmission means for moving the release lever to the operating position, the main shaft and cutter bar are not connected in high-speed drive states and cutoff states, and the main shaft is not engaged with the drive arm in low-speed drive states. By engaging the arms, the impact force at the time of engagement can be reduced, damage can be prevented, and the engagement can be performed reliably, which is an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a partial front view showing an embodiment of a buttonhole sewing machine embodying the present invention, Fig. 2 is an enlarged front view of main parts, Fig. 3 is an enlarged plan view of main parts, and Fig. 4 is a control means. FIG. 5 is a partially enlarged plan view showing the operating state of the device, and FIG. 5 is a partially enlarged side view. Main shaft...1, fixed pulley...2, floating pulley...
...3, Belt...6, Actuation arm...12 (said 2,
3, 6, and 12 constitute a clutch mechanism), clutch lever...7, drive arm...27,
Cutter bar...30, Cutter...32, Intermediate part...39, Swing lever...38, Engagement arm...4
3. Fitting portion...44, Tension spring...47 (constituting urging means), Moving collar...52 (constituting stopper means), Release lever...55,
Actuation lever...58, shaft...64, release arm...6
5. Connecting rod...67 (above 58, 64, 6
5 and 67 constitute a transmission means).

Claims (1)

[Claims] 1. Provided between the main shaft 1 of the sewing machine and the motor,
A high-speed drive state in which the rotation of the high-speed rotary pulley 4 is transmitted to the main shaft 1, a low-speed drive state in which the rotation of the low-speed rotary pulley 5 is transmitted to the main shaft 1, and a cutoff state in which the rotation of both pulleys 4 and 5 is not transmitted to the main shaft 1. Clutch mechanisms 2, 3, 6, 12 that are movably provided on the sewing machine frame and that switch the states of the clutch mechanisms 2, 3, 6, 12, and a clutch lever 7 that is rotatable on the sewing machine frame. a drive arm 27 that is supported by the frame and constantly swings in conjunction with the main shaft 1; and a cutter that is supported to be movable up and down on the frame and is used to cut the center part of the buttonhole stitch that has been sewn at the lower end. 32 is attached to the cutter bar 30; a swinging lever 38 having an intermediate portion 39 swingably supported on the frame and one end operatively connected to the cutter bar 30; and the swinging lever 38 and others. An engaging arm 43 is rotatably connected at one end and has a fitting portion 44 at the other end capable of fitting into the drive arm 27; driving arm 2
7. Biasing means 47 that biases in the direction of fitting into 7.
The engaging arm 43 is always locked and the engaging arm 4 is
The fitting portion 44 of No. 3 is separated from the drive arm 27,
stopper means 52 for releasing the engagement arm 43 at the end of one sewing cycle and allowing the engagement arm 43 to rotate toward the drive arm 27 by the biasing means 47; The rocking motion causes the fitting portion 44 to
In a buttonhole sewing machine configured such that the cutter rod 30 is moved up and down by the transmission to the engaging arm 43 via and an active position where the engaging arm 43 is detached from the engaging arm 43 and allowed to rotate toward the driving arm 27 by the action of the stopper means 52. A release lever 55 provided on the frame, and a release lever 55 provided between the release lever 55 and the clutch lever 7, and the clutch mechanism 2, 3, 6,
When the clutch lever 7 is placed in a position where the clutch mechanism 12 is placed in a disconnected state and a high-speed driving state, the release lever 55 is moved to the lower operating position and the clutch mechanisms 2, 3, 6, and 12 are brought into a low-speed state. A safety device for a buttonhole sewing machine, comprising transmission means 58, 64, 65, 67, etc., for moving the release lever 55 to the operating position when the clutch lever 7 is placed in the operating position.