JPS6325795B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a lower thread remaining amount detection device for a sewing machine, which is suitably used in, for example, an automatic cycle sewing machine or a sewing machine for automatic thread trimming.

Prior Art In conventional automatic thread insertion sewing machines, the bobbin with bobbin thread wound thereon is stored in a bobbin case, and since this bobbin case is attached to a hook located at the bottom of the sewing machine bed, the amount of bobbin thread remaining in the bobbin is cannot be observed from the outside. Therefore, sewing continues until the bobbin thread runs out completely, that is, until no stitches are formed, so when sewing that requires continuous stitches, the work must be interrupted midway when the bobbin thread runs out completely. There is a need to. In addition, it was necessary to start sewing again from the beginning, resulting in a significant decrease in the efficiency of sewing work.

The prior art for solving such problems is
It is disclosed in Japanese Patent Publication No. 43-11947. In this prior art, perforations are formed in each side wall of the thread catcher, the lower case, and the upper case. A tactile tongue piece is inserted into these perforations and is configured to come into contact with the bobbin thread wound around the bobbin to detect the remaining amount of the bobbin thread. In such prior art, the thread catcher has a track groove formed on its inner circumferential surface, the lower case has a track formed on its outer circumferential surface, and the track fits into the track groove and is inserted into the thread catcher. The lower case is supported. Therefore, during sewing, the thread catcher is rotated at high speed, so lubricating oil is supplied between the rail and the track groove to reduce frictional resistance and prevent the thread catcher from seizing. The configuration is common. In view of such prior art, it has been found that by forming perforations in the peripheral wall of the hook, the lubricating oil interposed between the rail and the rail groove is scattered into the upper case when the thread catcher rotates. I end up. A problem arises in that the bobbin thread wound around the bobbin is contaminated by such scattered lubricating oil.

Another prior art is disclosed in Japanese Utility Model Publication No. 46-21612. In this prior art, a light projecting hole and a light receiving hole are formed in the peripheral wall of the bobbin case. Therefore, in order to irradiate light into such a light emitting hole and receive the light that has passed through the light receiving hole, the outer hook and inner hook must be placed at positions corresponding to the light emitting hole and the light receiving hole of the bobbin case. An insertion hole must be provided in the Even with such prior art,
Similar to the prior art mentioned above (Japanese Patent Publication No. 43-11947),
There is a problem in that the bobbin thread is contaminated by lubricating oil. Moreover, in a configuration that detects the amount of bobbin thread remaining by shining light onto the bobbin below the sewing machine bed, the light may be diffusely reflected by loose thread dust in the light path, or scattered lubricating oil may It adheres to the light receiver, etc., and tends to cause malfunctions, resulting in poor reliability.

Problems to be Solved by the Invention The purpose of the present invention is to solve the above-mentioned technical problems,
It is possible to detect the bobbin thread wound around the bobbin without staining or damaging it, and it is also possible to accurately and reliably detect the remaining bobbin thread amount without causing any malfunction during detection. It is an object of the present invention to provide a bobbin thread remaining amount detecting device.

Means for Solving the Problems The present invention provides a bobbin case that is housed in an inner hook,
In a bobbin thread remaining amount detection 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, the shaft of the inner hook is connected to the bobbin. The winding tube of the bobbin is formed shorter than the winding tube, and has a detection hole penetrating in the radial direction of the winding tube closer to the open end of the inner hook than the top of the shaft, and has a nozzle hole at the tip. The nozzle member can be inserted into and removed from the winding tube at a position closer to the open end of the inner pot than the detection hole, and means for supplying compressed air to the nozzle member is provided, and the compressed air is supplied upstream of the nozzle hole. A bobbin thread remaining amount detecting device for a sewing machine is provided with a pressure detector for detecting pressure, and detects whether the detection hole is closed by the bobbin thread based on the output of the pressure detector. .

Function According to the present invention, when the nozzle member is inserted into the winding tube, the nozzle hole is opened facing the air inside the winding tube. 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 of the pressurized air on the upstream side of the nozzle hole decreases, and such a low pressure is detected by the pressure detector. In addition, when the bobbin is sufficiently wound with the bobbin thread, the detection hole is blocked by the bobbin thread wound around the bobbin, so the compressed air supplied into the bobbin is blocked. cannot flow out of the winding tube through the detection hole. This causes the upstream pressure of the compressed air to rise, and this high pressure is detected by the pressure detector. By detecting the pressure corresponding to the open/closed state of the detection hole in this manner, the remaining amount of bobbin thread on the bobbin can be detected.

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 3k of the sewing machine, and serves as a storage means for sequentially supplying a replenishing bobbin case 4 in which a bobbin wound with bobbin thread is stored. a chute 5, and a first gripping means 7 for gripping a bobbin case 6k attached to the inner hook 3 of the sewing machine together with the bobbin;
a second gripping means 8 for gripping the bobbin case 4 for replenishment from the chute 5; a lower thread remaining amount detection device 151 for detecting the remaining amount of the bobbin thread wound around the bobbin; and the lower thread remaining amount detection device 151. detects the remaining amount of bobbin thread wound on the bobbin attached to the inner hook 3k, and when replacing the bobbin case 6k attached to the inner hook 3k and the bobbin case 4 for replenishment supplied from the chute 5. and a moving means 9 for moving the first gripping means 7, the second gripping means 8, and the bobbin thread remaining amount detection device 151 so as to exchange them.

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.
The rotating shaft 10 includes an electric motor 12 as a driving means for driving the rotary shaft 10 so as to be angularly displaceable around its axis, and a double-acting cylinder 13 as a driving means for driving the swinging member 11 so as to be movable forward and backward in the axial direction 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 first gripping means 7 and a bobbin thread remaining at its end along the clockwise direction in FIG. The amount detection device 151 and the second gripping means 8 are arranged in this order. The distance L1 between the rotation shaft 10 and the first gripping means 7, the distance L2 between the rotation shaft 10 and the bobbin thread remaining amount detection device 151, and the distance L3 between the rotation shaft 10 and the second gripping means 8 are the same. be. A boss 14 is formed on such a swinging member 11. This boss 14
A screw hole 15 is bored in the screw hole 1.
The screw 16 screwed into the rotating shaft 10 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 an insertion hole 18 of the support 17 and guided by guide bushes 19 and 20 disposed within the insertion 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 an engagement groove 22 that engages with 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 this light shielding member 23a is formed on the gear 23.
A notch 23b is formed on the outer periphery of a for setting the amount of angular displacement of the swinging member 11 and for positioning the swinging member 11. A photoelectric switch 26 consisting of a light emitting element 24 and a light receiving element 25 is provided on both sides of the light shielding member 23a.
will be provided. When the swinging member 11 is angularly displaced to a predetermined position by this photoelectric switch 26,
Electric motor 12 is stopped by a brake mechanism.

Another gear 27 that can be engaged with the gear 23
is fixed to the output shaft 28 of the electric 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 through 180 degrees around its rotation axis, the rotation shaft 10 is rotated through 150 degrees according to the gear 23. The electric 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 low cylindrical joint body 33, a lid body 34 that is externally mounted on the joint body 33, and a radial shaft that is interposed in a space defined by the joint body 33 and the lid body 34. bearings 35 and 36. An internal thread 37 formed at the bottom of the joint body 33 has an external thread 3 formed at the tip of the rotating shaft 10.
8 are screwed together to fix the rotating 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. This flange 40
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 cross section taken from the section line V-V in FIG. It is a diagram. The chute 5 includes side plates 43, 44, a bottom plate 45, and an end plate 46, and the side plates 43, 44 and the bottom plate 45 are arranged so as to be inclined upward as they move away from the end plate 46. An opening 47 is formed between the end plate 41 and the side plate 44. Also, the side plate 43
The inner wall 43a has an engagement protrusion 4 extending in the longitudinal direction.
8 is formed, and an engagement groove 49 that can be engaged with this engagement protrusion 48 is formed in the replenishment bobbin case 4. The extending direction of the chute 5 having such a configuration is in a plane parallel to the swinging member 11,
Moreover, the opening 47 faces the second gripping means 8.
Refill bobbin cases 4 are housed in this chute 5 in parallel. When one refilling bobbin case 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 thus the second gripping means 8
The refill bobbin cases 4 in the chute 5 are sequentially taken out.

FIG. 6 is a flowchart showing the procedure of the bobbin exchange operation by the automatic bobbin exchange device 1, and FIG. 7 is a diagram for explaining the gripping operations of the first gripping means 7 and the second gripping means 8. First, sewing work is started in step m1, and when driving power is supplied to the sewing machine, the sewing machine is put into operation in step m2, and in step m3, the inner hook 3k is turned on.
The sewing machine is temporarily stopped for detecting the bobbin thread 77 of the bobbin 74k stored in the bobbin case 6k attached to the bobbin case 6k, or for replacement. In this state, the output shaft 32 of the double-acting cylinder 13 is extended in step m4, thereby causing the swinging member 11,
Therefore, the first gripping means 7 and the second gripping means 8
moves toward the inner hook 3k and the opening 47 side of the chute 5. Then, in step m5, the remaining amount of the lower thread 77 is detected by the lower thread remaining amount detection device 151. Such a situation is shown in FIG. 71. If the remaining amount of the bobbin thread 77 is sufficient for sewing, the process moves from step m5 to step m2 again, and 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 3 of the double-acting cylinder 13
2 is retracted, and thereby, following the swinging member 11, the gripping means 7, 8 and the bobbin thread remaining amount detection device 15
1 moves in a direction away from the inner pot 3k and the chute 5. Then, proceeding to step m7, the electric motor 12 is rotated 75 degrees clockwise from the position shown in FIG. 71 to the state shown in FIG. 72.
That is, the first gripping means 7 moves to a position facing the inner pot 3k, and the second gripping means 8 moves to a position facing the opening 4 of the chute 5.
Move to a position facing 7. In step m8, the output shaft 32 of the double-acting cylinder 13 is extended, and in step m9, the bobbin case 6k attached to the inner hook 3k is gripped by the first gripping means 7, and the bobbin case 6k is gripped by the second gripping means 8. Therefore, the refill bobbin case 4 stored in the chute 5
is grasped. Then, in step m11, the motor 12 rotates 150 degrees counterclockwise. As a result, the gripping means 7, 8 and the bobbin thread remaining amount detection device 15
1 is angularly displaced from the position shown in FIG. 72 to the position shown in FIG. 73.

Moving from step m11 to step m12,
The output shaft 32 of the double-acting cylinder 13 is extended, and the refill bobbin case 4 is attached to the inner hook 3 in step m13. At the same time, the bobbin case 6 stores the bobbin 74k in which the bobbin thread 77 has been consumed.
k is removed from the first gripping means 7 and falls downward. The bobbin 74k in which the bobbin thread 77 was consumed in this way
and a bobbin case 6k, and a replenishment bobbin case 6 that stores the bobbin 74k around which the bobbin thread 77 is wound.
are exchanged. After the replacement work is completed in this manner, the double-acting cylinder 13 retracts in step m14, and the swinging member 11 moves in a direction away from the inner hook 3k and the chute 5. Then, in step m15, the electric motor 12
Rotate 75 degrees clockwise. As a result, the gripping means 7, 8 and the lower thread remaining amount detecting device 151 return from the position shown in FIG. 73 to the original state shown in FIG. 71. Thereafter, the process returns from step m15 to step m2, and the series of operations described above is repeated to operate the sewing machine. When the bobbin thread 77 is consumed during operation of the sewing machine, it is possible to automatically replace it. .

FIG. 8 is a sectional view of the bobbin thread remaining amount detection device 151. The bobbin thread remaining amount detection device 151 provided in the automatic bobbin exchange 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 5.
0 and a nozzle hole 156. The nozzle hole 156 has a right cylindrical surface 156a.
, a conical surface 156b connected to this right cylindrical surface 156a and tapered toward the inner pot 3k, and a right cylindrical surface 1 connected to the small diameter end of this conical surface 156b.
56c, and a conical air outlet 1 which is connected to this right cylindrical surface 156c and tapers toward the inner pot 3k.
56d. A positioning pin 114 is provided on the outer circumferential surface of the nozzle member 57 in the vicinity of the air outlet 156d and protrudes radially outward from the outer circumferential surface. positioning. Such a nozzle member 15
7 is fixed to the swinging member 11. In addition, the flexible tube 15
8 is a nozzle member 157 by a fixing member 160.
is fixed to.

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
Inner hook 3k is placed in the raceway 70 defined by 9 and 9.
The track 71 is rotatably fitted therein. As a result, when the outer hook 67 is rotated at high speed by the rotating shaft 72, the inner hook 3k is housed in the outer hook 67.
remains stationary. An iron bobbin case 6k is housed in the inner hook 3k, and a bobbin 74k is housed within this bobbin case 6k. This bobbin 74k has a pair of iron flanges 73k, 7.
5k, and a right cylindrical winding tube 76k interposed between the flanges 73k and 75k. Winding tube 76
A lower thread 77 is wound around k.

FIG. 9 is a front view of the inner hook 3k and the vicinity of the bobbin case 6k, FIG. 10 is a sectional view of the inner hook 3k, and FIG. 11 is a front view seen from the arrow A6 side in FIG. 10. , Figure 12 shows the bobbin case 6k.
13 is a front view of the arrow A7 in FIG.
14 is a sectional view taken from the section line A8-A8 in FIG. 12, and FIG.
Figure 5 shows the bobbin 74 stored in the bobbin case 6k.
FIG. 16 is a sectional view taken along the section line A9-A9 in FIG. 15. Referring also to FIG. 8, a bobbin 7 is provided at the bottom 86 of the inner hook 3k.
A shaft portion 164 that fits into the 4k shaft hole 85k is formed. This shaft portion 164 has a through hole 165 that extends in a direction perpendicular to the axial direction, and another through hole 166 that extends in the axial direction and has one end communicating with the through hole 165 and the other end opening to the outside. is formed. Moreover, on the inner peripheral surface of the peripheral wall, there is a bobbin case 6k.
A retaining member 90 is fixed with a screw 91 to prevent the retaining member from coming off. This receiving member 90 is formed roughly in a U-shape, and its pair of legs 90
a acts as a leaf spring. This leg 90
A protrusion 92 is formed on a.

The bobbin case 6k includes a bobbin thread remaining amount detection device 15.
The insertion hole 1 into which the end of the nozzle member 157 of 1 is inserted.
18 is formed, and a positioning hole 119 is formed which is connected to this insertion hole 118 and into which the positioning pin 114 is inserted. bobbin case 6k
A notch 81 is formed in the peripheral wall of the notch 8.
An engagement hole 93 is formed in 1. The protrusion 92 of the retaining member 90 is engaged with the engagement hole 93, and thus the bobbin case 6k is engaged with the inner hook 3k.

The bobbin 74k includes a pair of flanges 73k and 75k arranged at an interval, and the flange 73k.
and a winding cylinder 76k that connects between k and 75k. A plurality of (four in this embodiment) detection holes 167 are formed in the winding tube 76k at equal intervals in the circumferential direction. A plurality of detection hole rows (two rows in this embodiment) are formed in the axial direction of the bobbin 74k.

The bobbin case 74k is the shaft part 164 of the inner hook 3k
8, the through hole 165 communicates with the left row of detection holes 167 formed in the bobbin 74k. Therefore, the compressed air ejected from the nozzle member 157 is ejected radially outward from the detection hole 167 on the right side via the air outlet 156d.
and is ejected radially outward from the through holes 167 in the left row through the space 169 defined by the shaft hole 85k and the shaft portion 164.

FIG. 17 is a flowchart illustrating in more detail the lower thread remaining amount detection operation in step m5 in the flowchart shown in FIG.
FIG. 8 is an air circuit diagram related to this lower thread remaining amount detection device 151. The air compressed from the air pressure source 50 is supplied to the outlet 156 of the nozzle hole 156 via the spring offset type two-position electromagnetic switching valve 170.
It is ejected from d. A pressure detection switch 159 is provided between the electromagnetic switching valve 170 and the nozzle hole 156, and this pressure detection switch 159 is connected to the processing circuit 5.
Connected to 6. Furthermore, the processing circuit 56 switches the electromagnetic switching valve 170 in response to the signal from the pressure detection switch 159. Referring to FIG. 17, the swinging member 11 moves toward the inner hook 3k in step m4, and the nozzle member 157 moves toward the shaft hole 85 of the bobbin 74k in step m5a.
It is attached to k. After that, the process moves to step m5b, where the processing circuit 56 switches the electromagnetic switching valve 170 to 170.
The position is switched from the position a 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 157 and blown out radially outward, as described above. When the bobbin thread 77 is sufficiently wound around the bobbin 74k, the detection hole 167 is closed, and therefore the nozzle hole 156
The air pressure within the flexible tube 158 becomes high, and such a state is detected by the pressure detection switch 159. When the pressure detection switch 159 detects high pressure, the processing circuit 56 activates the solenoid switching valve 1.
70 is switched to the stop position 170a. Then, the process moves from step m5b to step m2 again, and the sewing machine resumes operation. In step m5b, when the bobbin thread 77 wound around the bobbin 74k is 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 past has decreased. At this time, the processing circuit 56 controls the electromagnetic switching valve 1.
70 is switched to the stop position 170a. In this way, when it is detected in step m5b that the bobbin thread 77 wound around the bobbin is completely consumed,
The process moves from step m5b to step m6 to replace the consumed bobbin 74k with the replenishing 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, it becomes possible to easily detect the remaining amount of the bobbin thread 77 wound around the bobbin 74k. .

Effects As described above, according to the present invention, compressed air is supplied into the winding tube of the bobbin, and the pressure change is detected by the pressure detection switch, which is different from the prior art described above. As mentioned in connection, since the detection rod does not directly contact the bobbin thread wound around the bobbin, the bobbin thread will not be pierced or damaged. This prevents thread breakage. Furthermore, in this case, since the peripheral walls of the outer hook, inner hook, and bobbin case do not have openings, unlike the prior art, lubricating oil may scatter into the inside of the bobbin case and stain the bobbin thread. The problem of adhesion to devices placed around the kettle does not arise with the present invention. Furthermore, since malfunctions due to optical detection do not occur, the remaining amount of bobbin thread can be detected accurately and reliably.

[Brief explanation of the drawing]

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 along the section line V-V in FIG. 3, and FIG. 6 is a flowchart showing the procedure of bobbin exchange operation by the automatic bobbin exchange device 1. Chart, FIG. 7 shows the first gripping means and the second gripping means.
A diagram for explaining the gripping operation of the gripping means, FIG. 8 is a sectional view of the bobbin thread remaining amount detection device 151, FIG. 9 is a front view of the vicinity of the inner hook 3k and the bobbin case 6k,
Figure 10 is a sectional view of the inner pot 3k, and Figure 11 is a sectional view of the inner pot 3k.
FIG. 12 is a front view of the bobbin case 6k, FIG. 13 is a side view of the bobbin case 6k as seen from the arrow A7 side in FIG. 15 is a front view of the bobbin 74k stored in the bobbin case 6k, and FIG. 16 is a sectional view taken from the section line A8-A8 in FIG. 15.
9, FIG. 17 is a flowchart illustrating in more detail the lower thread remaining amount detection operation in step m5 in the flowchart shown in FIG. 6, and FIG. 18 is a lower thread remaining amount detection device. 151. FIG. 1... Automatic bobbin exchange device, 3k... Inner hook, 6k... Bobbin case, 5... Shoot,
7, 8...Gripping means, 9...Moving means, 10...
Rotating shaft, 11... Swinging member, 13... Double acting cylinder, 50... Air pressure source, 73k, 75k... Flange, 76k... Winding tube, 74k... Bobbin, 85
k...Shaft hole, 151...Bobbin thread remaining amount detection device, 15
2... Electric motor, 156... Nozzle hole, 157
... Nozzle member, 159 ... Pressure detection switch,
167...Detection hole.

Claims (1)

[Scope of Claims] 1. A bobbin thread of a sewing machine in which a bobbin case is stored in an inner hook, a bobbin on which a bobbin thread is wound is stored in the bobbin case, and the inner hook, bobbin, and bobbin case are arranged coaxially. In the remaining amount detection device, the shaft portion of the inner hook is formed shorter than the winding tube of the bobbin, and the winding tube of the bobbin has a radial direction of the winding tube closer to the open end of the inner hook than the top of the shaft portion. a detection hole penetrating through is formed, a nozzle member having a nozzle hole at the tip thereof can be inserted into and removed from the winding tube at a side closer to the open end of the inner pot than the detection hole, and means for supplying compressed air to the nozzle member. A pressure detector for detecting the pressure of the compressed air is provided on the upstream side of the compressed air from the nozzle hole, and based on the output of the pressure detector, it is detected whether the detection hole is closed by the bobbin thread. A bobbin thread remaining amount detection device for a sewing machine.