JPH0440039B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for detecting the remaining amount of bobbin thread in a sewing machine and automatically replacing a bobbin and a bobbin case.

Prior Art Conventionally, in order to detect the remaining amount of bobbin thread wound around the bobbin, a detection rod is inserted into the inner hook from a direction perpendicular to the axis of the inner hook, and the remaining amount of bobbin thread wound around the bobbin is detected. The presence or absence of the bobbin thread is detected by the angular displacement of the detection rod according to the amount of winding of the thread. Further, when such a bobbin thread remaining amount detecting means detects that the bobbin thread of the bobbin is consumed, the bobbin in order to replace the bobbin in the inner hook with the bobbin on which the bobbin thread is wound in advance. After the bobbin with the lower thread consumed is taken out from the inner hook by moving the means for gripping the bobbin toward or away from the inner hook, the bobbin with the lower thread wound thereon is mounted.

In such prior art, the power for driving the detection rod is derived from, for example, an electric motor, and the power for displacing the gripping means toward/away from the inner pot is derived from fluid pressure, such as pneumatic or hydraulic pressure. Since the bobbin thread remaining amount detection means and the gripping means must be driven individually by drive sources with different structures, the structure becomes complicated and large. has. Moreover, the bobbin thread is easily damaged by the detection rod inserted into the bobbin case, and the detection rod may come into contact with the bobbin thread that is drawn out from the coiled portion of the bobbin thread wound around the bobbin. , the problem arises that the tension changes undesirably.

Problems to be Solved by the Invention An object of the present invention is to use a simple configuration to detect the remaining amount of bobbin thread without damaging the bobbin thread wound around the bobbin, and to replace the bobbin with a new bobbin. To provide a bobbin exchange device for a sewing machine that allows the user to change a bobbin of a sewing machine.

Means for Solving the Problems The present invention provides a bobbin case that is housed in an inner hook,
In a bobbin changing device for a sewing machine in which a bobbin on which bobbin thread is wound is stored in a bobbin case, and an inner hook, bobbin, and bobbin case are arranged coaxially, a rotating shaft having a rotation axis parallel to the axis of the inner hook is used. A swinging member is provided on the rotating shaft, and a bobbin thread remaining amount detection means, a first gripping means, and a second gripping means are arranged at an end of the swinging member at intervals in the circumferential direction. The axes of the bobbin thread remaining amount detection means, the first gripping means, and the second gripping means are located on an imaginary circle centered on the axis of the rotating shaft, and the radius of this imaginary circle is within the radius of the imaginary circle. The distance is selected to be equal to the distance between the rotary hook axis and the axis of the rotary shaft, and the axis of any one of the bobbin thread remaining amount detecting means and the first gripping means and the second gripping means is selected to be within the distance in relation to the rotary shaft. means for driving the rotating shaft for angular displacement so that it is aligned with the axis of the rotary hook;
Means for driving the swinging member toward/away from the inner hook along the axial direction is provided, and a plurality of bobbin cases are stored below the inner hook, with the lowermost bobbin case being one of the bobbin cases. An opening that can be inserted in the axial direction is formed, and with the axis of the first gripping means being arranged coaxially with the inner hook axis, the axis of the bobbin case facing outside through the opening is aligned with the axis of the second gripping means. A storage means arranged coaxially with the axis is provided, and the bobbin has a pair of flanges and a right cylindrical winding tube connecting these flanges, and the winding tube has a radial direction. A penetrating detection hole is formed, the inner hook has a shaft portion that protrudes toward the open end side and is shorter than the winding cylinder of the bobbin, and the bobbin case has a shaft portion extending in the axial direction of the inner hook. A notch that extends and opens to the bottom side of the inner hook when installed in the inner hook, an engagement groove recessed on both sides of the notch, and an insertion hole that is coaxial with the axis of the inner hook are formed, A retaining member that fits into the notch and elastically engages with the engagement groove is fixed to the inner peripheral surface of the inner hook, and the bobbin thread remaining amount detection means has a nozzle hole at its tip. and a nozzle member for supplying compressed air into the winding cylinder from the nozzle hole on the open end side of the inner hook, the compressed air being supplied to the angular displacement driving means, the approaching/separating displacement driving means, and the nozzle member. A pressure detection means for detecting the pressure of the compressed air is provided upstream of the nozzle hole in the supply direction of the compressed air, and based on the output of the pressure detection means,
The rotating shaft is driven for angular displacement, and the first and second gripping means are formed with notches extending along the axial direction, fit into the winding cylinder, and have an outer diameter expanded/reduced in the radial direction, and the inner diameter is expanded/reduced in the radial direction. a fitting cylinder having a circumferential surface with an inclined surface whose diameter expands in a direction away from the inner hook; A bobbin exchange device for a sewing machine, comprising: a drive member that drives a backward displacement; and a pneumatic cylinder that drives the drive member forward/backward in an axial direction of an inner hook.

Effect According to the present invention, when the nozzle member is attached to the winding tube with the bobbin thread remaining amount detection means coaxial with the axis of the inner hook, the nozzle hole is located in the space inside the winding tube. It will be in an open state. When compressed air is supplied to the nozzle member in this state, if the bobbin thread is not wound around the bobbin or the amount of winding is insufficient, the compressed air is supplied from the nozzle hole into the winding cylinder. The compressed air flows out of the winding tube through the detection hole. As a result, the pressure on the upstream side of the nozzle hole in the compressed air supply direction decreases,
Such a low pressure is detected by the pressure detection means. In addition, when the bobbin thread is sufficiently wound around the bobbin, the detection hole is blocked by the bobbin thread, and the compressed air supplied to the winding tube passes through the detection hole. cannot flow outside. As a result, the pressure on the upstream side in the supply direction of compressed air increases, and such high pressure is detected by the pressure detection means.

Based on the output from the pressure detection means, if the pressure is low, the bobbin replacement operation is performed. The bobbin thread remaining amount detection means is angularly displaced from a state coaxial with the axis of the inner hook, and the first gripping means is brought into a state coaxial with the axis of the inner hook. In this state, the fitting tube of the first gripping means is inserted into the winding tube of the bobbin and expanded, whereby the bobbin is gripped by the fitting tube. When the swinging member is displaced and driven in the direction away from the inner hook in this state, the bobbin is taken out from the inner hook together with the bobbin case, and is held by the second gripping means in the same manner as the first gripping means. The bobbin case containing the bobbin wound with the bobbin thread is taken out from the storage means. In this way, the swinging member is driven to undergo an angular displacement while gripping the bobbin and the bobbin case, and the second gripping means becomes coaxial with the axis of the inner hook. In this state, when the swinging member is displaced and driven in a direction approaching the inner hook, the bobbin is attached to the inner hook together with the bobbin case. In this way, the bobbin in the inner hook and the bobbin stored in the storage means are exchanged.

Embodiment FIG. 1 is a simplified cross-sectional view of an automatic bobbin changing device 1, and FIG. 2 is a side view of the automatic bobbin exchanger 1 as viewed from the side indicated by arrow A in FIG. On the bottom of bed 2 of the sewing machine,
The automatic bobbin exchange device 1 is fixed. This automatic bobbin changing device 1 is basically placed near the inner hook 3 of the sewing machine, and serves as a means for sequentially supplying a replenishing bobbin case 4 in which a bobbin wound with bobbin thread is stored. The chute 5, a first gripping means 7 that grips the bobbin case 6 attached to the inner hook 3 together with the bobbin, and a second gripping means 8 that grips the refill bobbin case 4 from the chute 5.
a lower thread remaining amount detection means 151 for detecting the remaining amount of the lower thread wound around the bobbin; and the lower thread remaining amount detection means 1.
51 detects the remaining amount of bobbin thread wound on the bobbin attached to the inner hook 3, and when replacing the inner hook 3.
Movement of moving the first gripping means 7, the second gripping means 8, and the bobbin thread remaining amount detection means 151 in order to replace the bobbin case 6 attached to the bobbin case 6 with the replenishment bobbin case 4 supplied from the chute 5. Means 9
including.

The moving means 9 includes a swinging member 11 that is swingable around the axis of a horizontal rotating shaft 10 and a swinging member 11 that is swingable around the axis of a horizontal rotating shaft 10.
a pneumatic motor 12 as an angular displacement driving means for driving 0 around its axis, and a swinging member 11.
It includes a double-acting cylinder 13 as a means for displacing and driving the inner pot 3 in a direction toward/away from the inner pot 3 along the axis of the rotating shaft 10.

As shown in FIG. 2, the swinging member 11 has a substantially T-shaped cross section perpendicular to its axis, and has a second
The first gripping means 7, the lower thread remaining amount detection means 151, and the second gripping means 8 are arranged in this order along the clockwise direction in the figure. The distance L1 between the rotating shaft 10 and the first gripping means 7, and the rotating shaft 10 and the bobbin thread remaining amount detecting means 1
51 and the distance L3 between the rotating shaft 10 and the second gripping means 8 are the same.

A boss 14 is formed on such a swinging member 11. A screw hole 15 is bored in this boss 14, and a screw 16 screwed into the screw hole 15 presses the outer peripheral surface of the rotating shaft 10, and the swinging member 11 is fixed to the rotating shaft 10. .

The rotating shaft 10 is inserted through through holes 18 formed in each of the support bodies 17 and guided by guide bushes 19 and 20 disposed within each through hole 18 . A spline 21 is formed between the guide bushes 19 and 20 of the rotating shaft 10, and a cylindrical gear 23 having a spline groove 22 that fits into the spline 21 is provided on the outer periphery of the spline 21. A light shielding member 23a is formed on the gear 23, and a cutout 23b for positioning the swinging member 11 by setting the amount of angular displacement of the swinging member 11 is formed in the outer peripheral edge of the light shielding member 23a. Light shielding member 2
A photoelectric switch 26 consisting of a light emitting element 24 and a light receiving element 25 is provided on both sides of 3a. Based on the output from the photoelectric switch 26, when the swinging member 11 is angularly displaced to a predetermined position, the pneumatic motor 12 is stopped by the brake mechanism.

Another gear 27 meshing with the gear 23
is fixed to the output shaft 28 of the pneumatic motor 12. The gear ratio between gear 23 and gear 27 is selected to be 5:6. Therefore, when the output shaft 28 is rotated by 180 degrees around its rotational axis, the gear 23 and the rotating shaft 10 are rotated by 150 degrees. The pneumatic motor 12 is fixed to the mounting plate 30 by screws 29. The support body 17 is fixed to the bed 2 of the sewing machine via a mounting plate 30 with screws (not shown).

The rotating shaft 10 is connected to an output shaft 32 of a double-acting cylinder 13 via a shaft joint 31. The shaft joint 31 includes a cylindrical joint body 33 with a bottom, a lid body 34 that is fitted onto the joint body 33, and a radial bearing 35 that is interposed in a space defined by the joint body 33 and the lid body 34. , 36. The joint body 3
An external thread 38 formed at the tip of the rotary shaft 10 is screwed into an internal thread 37 formed at the bottom of the rotary shaft 10, thereby fixing the rotary shaft 10 and the joint body 33.
Alternatively, the output shaft 32 is inserted through the insertion hole 39 of the lid 34, and a flange 40 is formed near the tip of the output shaft 32. A radial bearing 35 is interposed between the flange 40 and the joint body 33, and a radial bearing 36 is interposed between the flange 40 and the lid 34. Double acting cylinder 13
is fixed to the mounting plate 30 via a bracket 41 with screws 42.

3 is a perspective view of the chute 5, FIG. 4 is a side view seen from the arrow B side in FIG. 3, and FIG. 5 is a sectional view taken from the cutting plane line - in FIG. 3. .
This chute 5 has side plates 43, 44 and a bottom plate 45.
and an end plate 46, and the side plates 43, 44 and the bottom plate 45 are arranged to be inclined upward as they move away from the end plate 46. An opening 47 is formed between the end plate 46 and the side plate 44. Further, an engagement protrusion 48 extending in the longitudinal direction is formed on the inner wall 43a of the side plate 43, and an engagement groove 49 that can be engaged with the engagement protrusion 48 is formed in the replenishment bobbin case 4.

In the chute 5 having such a configuration, its extending direction is parallel to the swinging member 11, and the opening 47 faces the second gripping means 8. Refill bobbin cases 4 are housed in this chute 5 in parallel. When one of the lowermost refilling bobbin cases 4 is taken out from the chute 5 by the second gripping means 8, the remaining refilling bobbin cases 4 move downward by their own weight, and are thus removed by the second gripping means. 8
The refill bobbin cases 4 in the chute 5 are sequentially taken out.

FIG. 6 is a sectional view of the gripping means 7 and 8, and the seventh
The figure is a perspective view of the gripping means 7, 8. The first gripping means 7 basically includes an engaging member 12 that fits into the shaft hole 85 of the bobbin 74 and engages with the inner peripheral surface of the shaft hole 85.
4 and a single-acting cylinder 120 as a means for expanding the engagement member 124 radially outward. The single-acting cylinder 120 includes a rod 121 that is a drive member that can freely reciprocate in the axial direction, and a casing 122 that surrounds the rod 121. The casing 122 includes a right cylindrical outer cylinder 123 surrounding the rod 121, and a distal end (sixth) of the outer cylinder 123.
the engaging member 124 that constitutes the left end in the figure). This engagement member 124 has a large diameter portion 124a and a small diameter portion 124b. A piston 125 is connected to the rod 121.
25 slides along the inner wall 126 of the outer cylinder 123. A sealing member 127 is attached to this piston 125, and this sealing member 127 separates the chamber 120a of the outer cylinder 123 from the other chamber 1.
20b are hermetically sealed. A coil spring 128 is interposed between one side 129 of the chamber 120a and the piston 125. This coil spring 12
8, the piston 125 and the rod 121 are spring-biased in the direction away from the inner pot 3.

This chamber 120a is connected to a right cylindrical surface 130 formed in the large diameter portion 124a of the engagement member 124, and this right cylindrical surface 130 further has a conical surface 131 which is an inclined surface tapering toward the inner hook 3. Concatenate to. The conical surface 131 is further connected to a right cylindrical surface 132 formed on the small diameter portion 124b.

The tip of the rod 121 (the left end in FIG. 6) is formed into a truncated cone shape corresponding to the conical surface 131. The engaging member 124 has the right cylindrical surface 1
30, a notch 133 communicating with the conical surface 131 and the right cylindrical surface 132 is formed. Also, the engaging member 1
A positioning pin 134 is formed in the large diameter portion 124a of 24.

The outer hook 67 includes an outer hook body 68 and an inner hook presser 6.
9. This outer hook body 68 and inner hook presser 6
A track 71 of the inner hook 3 rotatably fits into a track 70 defined by 9 and 9. An iron bobbin case 6 is housed in the inner hook 3, and a bobbin 74 is housed within this bobbin case 6. This bobbin 74 consists of a pair of iron flanges 73 and 75 and a right cylindrical winding tube 76 interposed between the flanges 73 and 74. A lower thread 77 is wound around the winding tube 76.

8 is a sectional view of the inner hook 3, FIG. 9 is a front view of the retaining member 90 seen from the arrow A1 side in FIG. 8, and FIG. 10 is a front view of the bobbin case 6. , FIG. 11 is a plan view seen from the arrow A2 side in FIG. 10, and FIG. 12 is a sectional view taken from the section line - in FIG. 10. The bottom portion 86 of the inner hook 3 is provided with a shaft portion 79 that projects toward the open end side. This shaft portion 79 is the lower shaft 72 of the outer hook 67.
It has a common axis with the axis of. The bobbin case 6 is formed with an insertion hole 118 through which the small diameter portion 124b of the engagement member 124 of the first gripping means 7 can be inserted, and a positioning hole 119 into which the positioning pin 134 is fitted.

A roughly U-shaped retaining member 90 is fixed to the inner circumferential surface of the inner hook 3 with a screw 91. A pair of protrusions 92 of this retaining member 90 are attached to the bobbin case 6.
The leg portions 90a, 90 of the retaining member 90 fit into the engaging groove 93 formed facing the notch 81.
b, it is elastically engaged with the engagement groove 93. As a result, the bobbin case 6 is fixed to the inner hook 3.

FIG. 13 is a pneumatic circuit diagram of the automatic exchange device 1. Compressed air from an air pressure source 50 is passed through a filter 51, regulated to a predetermined pressure by a pressure regulator 52, and supplied to a pipe 54 via a lubricator 53. The compressed air from the pipe line 54 is passed through a spring offset type two-position electromagnetic switching valve 5.
5 through position 55a or 55b of cylinder 1
It is supplied to each of the three rooms 13a and 13b.

When the electromagnetic switching valve 55 is not excited,
The electromagnetic switching valve 55 is located at position 55a, and the compressed air from the pipe 54 is transferred to position 5 of the electromagnetic switching valve 55.
5a to the chamber 13b of the double-acting cylinder 13, and the chamber 13a is open to the atmosphere. As a result, the output shaft 32 of the double-acting cylinder 13 retracts, thereby moving the rotary shaft 10 and, therefore, the swinging member 11 in the direction of arrow A in FIG. Therefore, the first
The gripping means 7 and the second gripping means 8 are separated from the inner hook and the chute 5.

When the electromagnetic switching valve 55 is energized by the processing circuit 56, the electromagnetic switching valve 55 is located at the position 55b, so that the compressed air from the line 54 is routed through the electromagnetic switching valve 55 at the position 55b. Double acting cylinder 1
3 room 13a. Double acting cylinder 13
The room 13b is opened to the atmosphere. As a result, the output shaft 32 is extended, and the rotating shaft 10 and the swinging member 11 are moved in the direction opposite to the arrow A in FIG. Therefore, the first gripping means 7 and the second gripping means 8 are in a state close to the inner pot 3 and the chute 5.

Further, compressed air from the conduit 54 is applied to the oscillating pneumatic motor 12 via a spring offset type two-position electromagnetic switching valve 57 at position 57a or 57b. When the electromagnetic switching valve 57 is not excited, the valve of the pneumatic motor 12 is stationary at one of the shortest positions. When the electromagnetic switching valve 57 is energized by the processing circuit 56, the electromagnetic switching valve 57 is in position 5.
7b, and the compressed air from the conduit 54 is connected to the pneumatic motor 12 via the electromagnetic switching valve 57 at position 57b.
given to. As a result, the output shaft 28 of the pneumatic motor 12 is angularly displaced by 180 degrees clockwise until it reaches the other shortest position and remains stationary in this state. This rotation of the output shaft 28 of the pneumatic motor 12 causes the rotating shaft 10 and the swinging member 11 to be angularly displaced by 150 degrees via the gears 27 and 23.

Compressed air from the pipe line 54 is passed through a spring offset type two-position solenoid switching valve 135 to the single-acting cylinders 120 provided in the gripping means 7 and 8, respectively.
is supplied to the room 120b. Solenoid switching valve 135
When the single-acting cylinder 12 is not energized, the single-acting cylinder 12
0 rod 121 is in a retracted state by spring 128 (see FIG. 6). When the electromagnetic solenoid 135 is energized by the processing circuit 56, compressed air from the conduit 54 is applied to the chamber 120b of the single-acting cylinder 120, and the rod 121 is activated by the spring 12.
It moves to the inner hook 3 side against the spring force of 8. This allows the tip of the rod 121 to connect to the engaging member 124.
Expand it to the top and bottom of Figure 6. As a result, the bobbin 74 is pushed apart while being engaged with the inner wall of the shaft hole 85, and the bobbin 74 and the bobbin case 6 are thus gripped by the first gripping means 7. Note that the second gripping means 8 also holds the replenishment bobbin case 4 stored in the chute 5 by a similar operation.
can be grasped.

FIG. 14 is a sectional view of the bobbin thread remaining amount detection means 151. The bobbin thread remaining amount detecting means 151 provided in the automatic bobbin changing device 1 described above includes a nozzle member 157 having a nozzle hole 156 therein, an air pressure source 50 that supplies compressed air, and this air pressure source 50. Flexible tube 15 communicating with nozzle hole 156
8 and a pressure detection switch 159 that detects the air pressure within the flexible tube 158.

The nozzle hole 156 includes a right cylindrical surface 156a, a conical surface 156b that is connected to the right cylindrical surface 156a and tapers toward the inner pot 3, and a conical surface 156a.
a right cylindrical surface 156c connected to the small diameter end of 6b;
It has a conical air outlet 156d that is connected to this right cylindrical surface 156c and expands toward the inner pot 3.

A positioning pin 114 is provided on the outer peripheral surface of the nozzle member 157 near the air outlet 156d and protrudes radially outward from the outer peripheral surface, and the positioning pin 114 is fitted into a positioning hole 119 formed in the bobbin case 6. The positioning of the bobbin case 6 can be performed in a detailed manner. Such a nozzle member 157 is fixed to the swinging member 11. Further, the flexible tube 158 is fixed to the nozzle member 1 by the fixing member 160.
57.

The shaft portion 79 of the inner hook 3 has a through hole 165 extending in a direction perpendicular to the axial direction, and another through hole extending in the axial direction and having one end communicating with the through hole 165 and the other end opening to the outside. A hole 166 is formed.

15 is an axis-perpendicular sectional view of the bobbin 74 housed in the bobbin case 6, and FIG. 16 is a sectional view taken along the section line - in FIG. 15. A plurality of detection holes 167 (four in this embodiment) are formed in the winding tube 76 of the bobbin 74 at equal intervals in the circumferential direction. These detection holes 167
A plurality of rows (two rows in this embodiment) are formed in the axial direction of 4.

When the bobbin case 74 is attached to the shaft portion 79 of the inner hook 3, the through hole 165 communicates with the left row detection hole 167a formed in the bobbin 74, as shown in FIG. Therefore, the compressed air ejected from the nozzle member 157 is
6d from the detection holes 167a in the left row, and the detection holes in the right row are ejected radially outward from the detection holes 167a in the left row through the air outlet 156d, the shaft hole 85, and the shaft portion 164. It is ejected radially outward from the hole 167b.

FIG. 17 is a flowchart showing the procedure of bobbin exchange operation by the automatic bobbin exchange device 1, and FIG.
The figure is a diagram for explaining the gripping operation of the first and second gripping means 7 and 8. First, sewing work is started in step m1, and when driving power is supplied to the sewing machine, the sewing machine becomes operational in step m2, and in step m3, the bobbin thread is threaded onto the bobbin 74 stored in the bobbin case 6 in the inner hook 3. 77, the sewing machine is temporarily stopped.

In this state, in step m4, the output shaft 32 of the double-acting cylinder 13 is extended, whereby the swinging member 11, and therefore the first gripping means 7 and the second gripping means 8, are 5
It moves toward the opening 47 side. and step
At m5, the remaining amount of the lower thread 77 is detected by the lower thread remaining amount detection means 151. Such a state is shown in FIG. 18.

If the remaining amount of the bobbin thread 77 is sufficient for sewing, the process moves from step m5 to step m2 again.
The sewing machine is operated again. In step m5, if the remaining amount of the bobbin thread 77 is insufficient for sewing work, or if the bobbin thread is completely consumed, the process moves to step m6, and the output shaft 32 of the double-acting cylinder 13
is retracted, thereby the swinging member 11 retreats, and the gripping means 7, 8 and the bobbin thread remaining amount detection means 15
1 moves in a direction away from the inner hook 3 and the chute 5. Then, proceeding to step m7, the output shaft 28 of the pneumatic motor 12 is rotated 75° clockwise from the position shown in FIG.
The first gripping means 7 is moved to the position shown in FIG.

In step m8, the output shaft 32 of the double-acting cylinder 13 is extended, and in step m9, the first
The bobbin case 6 inside the inner hook 3 is held by the gripping means 7.
is gripped, and the refill bobbin case 4 in the chute 5 is gripped by the second gripping means 8. Then, in step m11, the output shaft 28 of the pneumatic motor 12 is rotated 150° counterclockwise. As a result, the gripping means 7, 8 and the lower thread remaining amount detection means 151 are angularly displaced from the position shown in FIG. 18 to the position shown in FIG. 18.

Moving from step m11 to step m12, the output shaft 32 of the double-acting cylinder 13 is extended, and in step m13, the refill bobbin case 4 is moved to the inner hook 3.
will be installed on the At the same time, the bobbin case 6 storing the bobbin 74 in which the bobbin thread 77 has been consumed is moved to the first bobbin case 6.
It is removed from the gripping means 7 and falls downward. The bobbin 74 and bobbin case 6 in which the bobbin thread 77 has been consumed in this way are replaced with the replenishment bobbin case 6 that accommodates the bobbin 74 around which the bobbin thread 77 has been wound.

After the replacement work is completed in this way, in step m14, the output shaft 3 of the double acting cylinder 13 is
2 retracts, and the swinging member 11 moves in a direction away from the inner pot 3 and the chute 5. Then, in step m15, the output shaft 28 of the pneumatic motor 12 is
rotates 75° clockwise. As a result, the gripping means 7, 8 and the bobbin thread remaining amount detection means 151
8 The position shown in FIG. 3 returns to the original state shown in FIG. 18. Then step m15
Then, the process returns to step m2 again, and the sewing machine is operated by repeating this series of operations. When the bobbin thread 77 is consumed during operation of the sewing machine, it becomes possible to automatically replace it.

FIG. 19 is a flowchart for explaining in more detail the bobbin thread remaining amount detection operation in step m5 in the flowchart shown in FIG. 17, and FIG. This is an air circuit diagram. Compressed air from the air pressure source 50 is blown out from the outlet 156d of the nozzle hole 156 via the spring offset type two-position electromagnetic switching valve 170. Solenoid switching valve 17
Pressure detection switch 1 is connected between 0 and nozzle hole 156.
59 is provided, and this pressure detection switch 159 is connected to the processing circuit 56. Also, the processing circuit 56
In response to the signal from the pressure detection switch 159, the electromagnetic switching valve 170 is switched.

At step m4 (see Fig. 17), the swinging member 11 moves toward the inner hook 3, and the step
At m5a, the nozzle member 157 is attached to the shaft hole 85 of the bobbin 74. After that, the process moves to step m5b, and the solenoid switching valve 170 is set to 17 by the processing circuit 56.
The position is switched from the position 0a to the position 170b, and at the same time, compressed air from the air pressure source 50 is blown out from the outlet 156d through the nozzle hole 156 of the nozzle member 157.

This blown out compressed air is guided to the detection hole 167 and blown out radially outward, as described above. When the bobbin thread 77 is sufficiently wound around the bobbin 74, the detection hole 167 is closed, and therefore the air pressure inside the nozzle hole 156 and the flexible tube 158 becomes high. Detected by switch 159. When the pressure detection switch 159 detects high pressure, the processing circuit 56 switches the electromagnetic switching valve 170 to the stop position 170a. Then step again from step m5b.
Move to m2 and the sewing machine resumes operation.

In step m5b, when the bobbin thread 77 wound around the bobbin 74 has been consumed and is running low, compressed air is blown out from the detection hole 167 in the radial direction. It is detected that the pressure of the compressed air flowing therethrough has decreased. At this time, the processing circuit 5
6, the electromagnetic switching valve 170 is at the stop position 170a.
can be switched to

In this way, when it is detected in step m5b that the bobbin thread 77 wound on the bobbin is completely consumed, the process moves from step m5b to step m6.
The process moves on to replacing the consumed bobbin 74 with the replenishment bobbin 4.

Since the pressure detection switch 159 detects the pressure change of the compressed air from the air pressure source 50 in this way, the remaining amount of the bobbin thread 77 wound around the bobbin 74 can be easily and easily damaged. It becomes possible to detect it without any trouble.

Effects As described above, according to the present invention, the remaining amount of bobbin thread is detected using compressed air from one compressed air supply means and the first and second gripping means are driven. The configuration can be simplified by reducing the amount of noise, and the device can be made smaller.

Also, during detection, compressed air is supplied into the winding cylinder of the bobbin, and the pressure change is detected by a pressure detection switch, so the detection rod does not come into direct contact with the bobbin thread wound on the bobbin. Damage to the thread can be prevented.

[Brief explanation of drawings]

FIG. 1 is a simplified sectional view of the automatic bobbin exchange device 1, FIG. 2 is a side view seen from the arrow A side in FIG. 1, FIG. 3 is a perspective view of the chute 5, and FIG. 3
5 is a sectional view taken from the cutting plane line - in FIG. 3, FIG. 6 is a sectional view of the gripping means 7 and 8, and FIG. 7 is a sectional view of the gripping means 7. , 8 is a sectional view of the inner hook 3, and FIG. 9 is a sectional view of the inner hook 3.
A front view of the retaining member 90 seen from the arrow A1 side in the figure, FIG. 10 is a front view of the bobbin case 6, and FIG.
The figure is a plan view seen from the arrow A2 side in Figure 10.
2 is a sectional view taken from the cutting plane line - in FIG. 10, and FIG. 13 is an air circuit diagram of the automatic exchange device 1.
14 is a sectional view of the bobbin thread remaining amount detection means 151, and FIG. 15 is a sectional view of the bobbin 74 housed in the bobbin case 6.
FIG. 16 is a sectional view taken along the cutting plane line - of FIG. 19 is a flowchart for explaining in more detail the lower thread remaining amount detection operation at step m5 in the flowchart shown in FIG. 17. FIG. 20 is an air circuit diagram related to this lower thread remaining amount detection means 151. 1... Automatic bobbin exchange device, 3... Inner hook,
4, 6...Bobbin case, 5...Shoot, 7,
8... Gripping means, 9... Moving means, 10... Rotating shaft, 11... Swinging member, 12... Pneumatic motor,
13...Double acting cylinder, 50...Pneumatic pressure source, 74
...bobbin, 77 ... bobbin thread, 151 ... bobbin thread remaining amount detection means, 156 ... nozzle hole, 157 ... nozzle member, 159 ... pressure detection switch, 165,
166...Through hole.

Claims (1)

[Claims] 1. A bobbin replacement for a sewing machine in which a bobbin case is stored in the inner hook, a bobbin on which bobbin thread is wound is stored in the bobbin case, and the inner hook, bobbin, and bobbin case are arranged coaxially. In the device, a rotating shaft having a rotational axis parallel to the axis of the inner hook is provided, a swinging member is provided on the rotating shaft, and the swinging member is provided at an end thereof at intervals in a circumferential direction. A bobbin thread remaining amount detection means, a first gripping means, and a second gripping means are provided, and the respective axes of the bobbin thread remaining amount detection means, the first gripping means, and the second gripping means are aligned with the axis of the rotating shaft. The radius of this virtual circle is selected to be equal to the distance between the inner hook axis and the axis of the rotating shaft. means for driving the rotary shaft by angular displacement so that the axis of either one of the first gripping means and the second gripping means is aligned with the axis of the inner pot;
Means for driving the swinging member toward/away from the inner hook along the axial direction is provided, and a plurality of bobbin cases are stored below the inner hook, with the lowermost bobbin case being one of the bobbin cases. An opening that can be inserted in the axial direction is formed, and with the axis of the first gripping means being arranged coaxially with the inner hook axis, the axis of the bobbin case facing outside through the opening is aligned with the axis of the second gripping means. A storage means arranged coaxially with the axis is provided, and the bobbin has a pair of flanges and a right cylindrical winding tube connecting these flanges, and the winding tube has a radial direction. A penetrating detection hole is formed, the inner hook has a shaft portion that protrudes toward the open end side and is shorter than the winding cylinder of the bobbin, and the bobbin case has a shaft portion extending in the axial direction of the inner hook. A notch that extends and opens to the bottom side of the inner hook when installed in the inner hook, an engagement groove recessed on both sides of the notch, and an insertion hole that is coaxial with the axis of the inner hook are formed, A retaining member that fits into the notch and elastically engages with the engagement groove is fixed to the inner peripheral surface of the inner hook, and the bobbin thread remaining amount detection means has a nozzle hole at its tip. and a nozzle member for supplying compressed air into the winding cylinder from the nozzle hole on the open end side of the inner hook, the compressed air being supplied to the angular displacement driving means, the approaching/separating displacement driving means, and the nozzle member. A pressure detection means for detecting the pressure of the compressed air is provided upstream of the nozzle hole in the supply direction of the compressed air, and based on the output of the pressure detection means,
The rotating shaft is driven for angular displacement, and the first and second gripping means are formed with notches extending along the axial direction, fit into the winding cylinder, and have an outer diameter expanded/reduced in the radial direction, and the inner diameter is expanded/reduced in the radial direction. a fitting cylinder having a circumferential surface with an inclined surface whose diameter expands in a direction away from the inner hook; 1. A bobbin changing device for a sewing machine, comprising: a drive member that drives a backward displacement; and a pneumatic cylinder that drives the drive member forward/backward in an axial direction of an inner hook.