Sewing machine and computer readable medium storing sewing needle status evaluation program

Abstract

A sewing machine provided with a needle bar having a sewing needle interchangeably attached to its lower end including an imaging element that captures images of the sewing needle; an extractor that extracts a shape of the sewing needle from the images of the sewing needle captured by the imaging element; an abnormality determiner that determines presence/absence of abnormalities in measurements of the sewing needle based on the shape of the sewing needle extracted by the extractor; and an abnormality alerter that alerts the presence of abnormalities determined by the determiner.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application 2008-033212, filed on Feb. 14, 2008, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a sewing machine allowing interchangeable attachment of sewing needle on a lower end of a needle bar. The present disclosure also relates to a computer readable medium storing a needle status evaluation program for use in such sewing machine.

BACKGROUND

A sewing machine in general is provided with a needle bar to which a sewing needle is detachably attached interchangeably to its lower end. Such detachable configuration allows the sewing needle to be replaced when the user encounters sewing needle wears during the sewing operation such as bending, broken tip, and rounded tip. Such detachable configuration also allows the user to selectively attach a desired sewing needle most suitable in thickness, for example, for sewing different types and thickness of workpiece cloth. In view of such mode of usage sewing machine generally comes with an accessory of replacement sewing needles of various thickness.

The timing in which the sewing needle replacement is made relies on user judgment based on visual recognition. Subtle bends or rounding of needle tip, however, is likely to be overlooked by the user if visual recognition is the only resort in making the judgment.

To address such issue, JP H11-221392 A discloses a needle breakage detector that automatically detects sewing needle breakage. The disclosed needle breakage detector comprises a proximity sensor for detecting the tip of the sewing needle at its lowermost point of vertical reciprocation. The sewing operation is immediately stopped as soon as needle breakage has been detected.

Though the above described needle breakage detector is capable of detecting needle breakages, detection of other wear (deterioration) such as bending and rounded tip are not guaranteed. Thus, it still rests upon user's visual recognition for detection of such wears. Another problem with the conventional needle breakage detector was its installation. Since the detector (proximity sensor) required installation at the lowermost point of needle reciprocation residing below the needle plate, where components such as rotary shuttle, feed dog drive mechanism, and thread cutting mechanism were installed, it was difficult to secure appropriate spacing for installation of the detector.

Another general problem encountered under the conventional sewing operation using the above described detector was inappropriate selection of a sewing needle for sewing a given type of workpiece cloth. For instance, if the user fails to select a sewing needle of appropriate thickness for workpiece cloth of different thickness and type, it may cause the sewing needle to bend or leave an oversized through hole on the workpiece cloth consequently impairing the look and quality of the resulting stitches. Further, an embroiderable sewing machine requires a sewing needle of a predetermined thickness when embroidering a multiplicity of stitches in order to obtain a descent embroidery pattern. The conventional detector, however, lacks in the capacity of determining whether or not the thickness of a given sewing needle is appropriate for the thickness and the type of workpiece cloth to be sewn.

SUMMARY

An object of the present disclosure is to provide a sewing machine that allows automatic evaluation of sewing needle wear without relying on user's visual recognition and decision to prevent malfunctioning caused by worn out sewing needles. Another object of the present disclosure is to provide a sewing machine that is capable of automatically determining whether or not a sewing needle of appropriate thickness has been attached for sewing a workpiece cloth of a given thickness or type and for executing embroidering sewing. Yet, another object of the present disclosure is to provide a computer readable medium that stores a sewing needle status evaluation program for realizing the above described features.

In one aspect, a sewing machine provided with a needle bar having a sewing needle interchangeably attached to its lower end includes an imaging element that captures images of the sewing needle; an extractor that extracts a shape of the sewing needle from the images of the sewing needle captured by the imaging element; a determiner that determines presence/absence of abnormalities in measurements of the sewing needle based on the shape of the sewing needle extracted by the extractor; and an alerter that alerts the presence of abnormalities determined by the determiner.

According to the above described configuration, the shape of sewing needle is extracted by the extractor from the image data of sewing needle captured by the imaging element and presence/absence of abnormalities in the sewing needle is determined by the determiner through evaluation of various measurements of the sewing needle. By verifying whether or not measurements such as the length of the sewing needle, widths of various portions of the sewing needle, and the distance between the center line and the edge of the sewing needle at various heights of the sewing needle is within a predetermined threshold range from the regular measurements of a brand new sewing needle, presence/absence of abnormalities that require replacement such as bending of sewing needle and broken tip and rounded tip can be determined. If determined that sewing needle is abnormal, an alert is issued to that effect by the alerter so that the user is promptly informed of the abnormalities of the sewing needle to prevent any trouble caused by unattended abnormalities.

In another aspect, a sewing machine provided with a needle bar having a sewing needle interchangeably attached to its lower end includes an imaging element that captures images of the sewing needle; an extractor that extracts a shape of the sewing needle from the images of the sewing needle captured by the imaging element; a storage that pre-stores an initial shape of the sewing needle; an abnormality determiner that determines presence/absence of abnormalities in the shape of the sewing needle extracted by the extractor by comparing with the initial shape pre-stored in the storage; and an alerter that alerts the presence of abnormalities determined by the determiner.

According to the above described configuration, images of the sewing needle captured by the imaging element is extracted by the extractor for comparison with the initially extracted shape data stored in the storage to determine the absence/presence abnormalities in the sewing needle by the determiner. By comparing the extracted shape and the pre-stored shape of the sewing needle to detect the difference in measurements of various portions of the sewing needle and verifying whether the difference is within a predetermined threshold range, absence/presence of abnormalities that require sewing needle replacement such as bending, tip rounding, and tip breakage can be determined. If abnormalities are found, an alert is issued to that effect by the alerter so that the user is promptly informed of the abnormalities of the sewing needle to prevent any trouble caused by unattended abnormalities.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present disclosure will become clear upon reviewing the following description of the illustrative aspects with reference to the accompanying drawings, in which,

FIG. 1 depicts a first exemplary embodiment of a sewing machine according to the present disclosure and provides a perspective view of the sewing machine;

FIG. 2 is a front view of the sewing machine with an embroidery machine attached;

FIG. 3 is an enlarged perspective view of a sewing needle;

FIG. 4 is a block diagram indicating an electrical configuration of the sewing machine;

FIG. 5A is a front view of the sewing needle;

FIG. 5B is an enlarged front view of the tip of the sewing needle maintaining its initial state;

FIG. 5C is an enlarged front view of the tip of the sewing needle halted at a leftwardly inclined position;

FIG. 5D is an enlarged front view of the tip of the sewing needle with a rounded tip caused by frictional wear;

FIG. 6A depicts a shape of the sewing needle free of bend;

FIG. 6B depicts a shape of the sewing needle halted at a leftwardly inclined position;

FIG. 6C depicts a shape of the sewing needle having a bend;

FIG. 7 indicates a flowchart describing an overall control flow of abnormality evaluation of sewing needle executed by a controller;

FIG. 8 is a flowchart elaborating step S3 of FIG. 7;

FIG. 9A depicts a second exemplary embodiment of the present disclosure and provides a front view of the sewing needle;

FIG. 9B provides an exemplary mapping of sewing needle thickness with sewing needle number;

FIG. 10 indicates a flowchart describing an overall control flow of needle thickness evaluation executed by the controller;

FIG. 11 elaborates step S21 of FIG. 10;

FIG. 12 elaborates step S23 of FIG. 10;

FIG. 13 elaborates step S25 of FIG. 10;

FIG. 14 depicts a third exemplary embodiment of the present disclosure and corresponds to FIG. 7; and

FIG. 15 elaborates step S44 of FIG. 14.

DETAILED DESCRIPTION

One exemplary embodiment of the present disclosure will be described with reference to FIGS. 1 to 8.

FIGS. 1 and 2 provide perspective views of the overall configuration of a sewing machine (household electronic sewing machine) in accordance with the present disclosure. FIG. 1 shows the sewing machine with a table attachment on its sewing machine bed for utility stitching and FIG. 2 shows the sewing machine with an embroidery machine attachment on its sewing machine bed for embroidering.

The main body of sewing machine 1 is provided integrally with a laterally (X-direction) extending sewing machine bed 2, an upwardly extending pillar 3 standing on the right end of sewing machine bed 2, and an arm 4 extending leftward over sewing machine bed 2 from the upper end of pillar 3. The extreme end of arm 4 constitutes a head 5. At the upper portion of arm 4, a cover 4a is provided for opening and closing access into the arm 4. Though not shown, arm 4 includes a compartment for storing a needle thread spool. For ease of explanation to follow, the direction to which the user positions him/herself relative to sewing machine 1 is the front side, and the opposing direction, naturally is the rear side. The direction toward which pillar 3 is displaced from the center of arm 4 is the right side and the opposing direction, naturally, is the left side.

As can be seen in FIG. 3, head 5 provided at the end of arm 4 has a needle bar 6 configured vertically movably and laterally (X-direction) swingably. At the lower end of needle bar 6, a sewing needle is attached by way of needle clamp 8 as can be seen in FIG. 5A. As known in the art, a fastening screw 9 is provided at the right end of needle clamp 8 to allow attachment/detachment (replacement) of sewing needle 7 by turning fastening screw 9. Sewing needle 7 may be subject to wears (deterioration) such as bend, broken tip, and rounded tip over time and use, which requires replacement of sewing needle 7 by the user.

Provided at the lower potion of needle bar 6 (sewing needle 7) extending from head 5, is a presser foot 10. At the left side of needle bar 6 (sewing needle 7) a needle threader (not shown) known in the art is provided for threading a needle thread drawn from a thread spool to a needle eye (not shown).

Though not explained in detail, arm 4 contains a sewing machine main shaft rotated by a sewing machine motor 12 (refer to FIG. 4). Arm 4 further contains a needle-bar drive mechanism driven by the sewing machine main shaft to vertically move needle bar 6, and a needle-bar swing mechanism driven by a needle-swing pulse motor 13 (refer to FIG. 4) to laterally (X-direction) swing needle bar 6. Arm 4 further contains components such as a thread take-up drive mechanism that vertically moves a thread take-up (not shown) in synchronism with the vertical movement of needle bar 6, and a thread tension regulator that adjusts thread tension.

Though not shown in detail, the sewing machine main shaft is provided with a sectoral shutter (blocking plate) rotating integrally with the main shaft. The rotational status of the shutter is detected optically by a photo-interrupter provided at a sewing machine frame. The shutter and the photo-interrupter constitute a main shaft angle detector 14 (refer to FIG. 4). The vertical positioning of needle bar 6 driven by the main shaft can be sensed by the angle of the main shaft detected by main shaft angle detector 14. Needle bar 6 is configured to stop at its lifted position (substantially the uppermost position of the vertical reciprocation) when the sewing operation is stopped by operation of the later described start/stop key 15a.

As can be seen in FIGS. 1 and 2, key switches 15 are provided on the front face of arm 4 for user operation. Though not explained in detail, key switches 15 comprise controls such as start/stop switch 15a that instructs start/stop of a sewing operation, a back stitch key, needle positioning key, thread cutting key, and a speed adjustment dial. On the front face of pillar 3, a vertically elongate liquid crystal display 20 (hereinafter simply referred as LCD 20) is provided for displaying various information in full color.

LCD 20 displays information such as various utility and embroidery patterns, names of various functions required in the sewing operation, and various informational messages. Selection of patterns and execution of functions are carried out through a touch panel 21 (refer to FIG. 4) provided on the surface of LCD 20. LCD 20 displays error messages (alert) when abnormality is found at sewing needle 7.

Referring to FIG. 1, a needle plate 16 is provided on the upper surface sewing machine bed 2. Though not shown, within sewing machine bed 2 situated below needle plate 16, are components such as a feed dog drive mechanism that drives a feed dog in synchronism with the vertical movement of needle bar 6, a full rotary shuttle containing a bobbin thread bobbin and forming stitches in cooperation with sewing needle 7, and a needle cutting mechanism that cuts the needle thread and bobbin thread. As can be seen in FIG. 1, a utility sewing table 24 is attachably/detachably attached to the left front portion of sewing machine bed 2. Utility sewing table 24 is used for sewing utility patterns on workpiece cloth (not shown) fed by the feed dog.

Referring to FIG. 2, a well known embroidery machine (embroidery frame transfer mechanism) may be attachably/detachably attached to the left front portion of sewing machine bed 2 instead of utility sewing table 24. Embroidery machine 22 is attachably/detachably attached with an embroidery frame (not shown) that holds the workpiece cloth (not shown). Embroidery machine 22 comprises an embroidery frame transfer mechanism (not shown) an X-directional motor (not shown) and a Y-directional motor (not shown). The embroidery frame transfer mechanism transfers the embroidery frame freely in the X-direction (lateral) and the Y-direction (longitudinal) orthogonal to the X-direction in the space overlying sewing machine bed 2 (needle plate 16) and is driven by the X-direction motor and the Y-direction motor. When embroidery machine 22 is attached to sewing machine bed 2, embroidery machine 22 and consequently X-directional and Y-directional motors are electrically connected to a later described controller 25 of the sewing machine through a connector 23 (refer to FIG. 4) provided at sewing machine bed 2. The attachment of embroidery machine 22 triggers automatic mode switching from utility sewing mode to embroidery sewing mode.

Referring now to FIG. 3, at the lower front end portion of head 5, which is, when viewed from sewing needle 7, a portion located forwardly and rightwardly upward relative to sewing needle 7, a first image sensor 17 is provided for capturing images of sewing needle 7. Referring back to FIG. 1, a second image sensor 18 is provided on the rear portion of the pillar 3 left wall facing the sewing needle 7 for capturing images of sewing needle 7. In the present exemplary embodiment, first and second image sensors 17 and 18 comprise a compact imaging device such as a CMOS (Complementary Metal Oxide Semiconductor) imaging device.

Sewing needle 7 and consequently needle bar 6 are halted at the lifted position elevated from needle plate 16 when the sewing operation is stopped. First and second image sensors 17 and 18 are located so that images of sewing needle 7 halted at the lifted position can be captured from different locations (angles).

Utility sewing involves different styles of stitching such as straight stitching and zigzag stitching. Zigzag stitching is carried out while laterally swinging needle bar 6 (sewing needle 7) by the needle-bar swing mechanism. Straight stitching is basically carried out at a central baseline with the center line of needle bar 6 (sewing needle 7) being orthogonal to the upper surface of needle plate 16. Straight stitching, however, may be carried out at a left baseline with needle bar 6 (sewing needle 7) leftwardly inclined or at a right baseline with needle bar 6 (sewing needle 7) rightwardly inclined. In such cases, as depicted somewhat exaggerated in FIG. 5C and FIG. 6B, needle bar 6 (sewing needle 7) is halted at a leftwardly swung (inclined) position according to a present swing width, and rightwardly swung (inclined) position for example. Angle of sewing needle 7 (angle of incline of sewing needle 7 relative to the center baseline) in this case, is set to a predetermined value obtained from the angular data that corresponds to a preset swing width.

As can be seen in FIG. 4, image data captured by first and second image sensors 17 and 18 respectively is inputted into image processing circuit 19. Though not described in detail, image processing circuit 19 transforms the perspective of the image captured by first image sensor 17 from the upper front view of sewing needle 7 into an image that substantially appears to be taken from the front side of sewing needle 7. At the same time, known image processing such as binarization and outline (edge) extraction are performed to extract the shape of sewing needle 7. Similarly, image processing circuit 19 performs binarization and outline (edge) extraction of the image captured by second image sensor 18 from the right side and rear side surface view of sewing needle 7. The extracted shape of sewing needle 7 by image processing circuit 19 is taken as input into controller 25 as shape data.

FIG. 4 briefly describes an electrical configuration of the sewing machine according to the present exemplary embodiment. Controller 25 is configured primarily by a microcomputer comprising components such as a CPU 26, a ROM 27, a RAM 28, and an EEPROM 29. ROM 27 stores various items such as a control program for controlling the sewing operation, a needle status evaluation program, stitch data required for the sewing operation, and various data required for verification of later described abnormalities of sewing needle 7. As will be described afterwards, needle evaluation program automatically evaluates wear of sewing needle 7. The needle status evaluation program may be executed by way of an external storage medium such as an optical disc, magnetic disc, and compact card or stick memory.

Controller 25 is connected to various keys switches 15 including start/stop switch 15a, and to touch panel 21 for receiving their operation signals. Controller 25 further establishes connection with main shaft angle detector 14 to receive its detection signal. As described earlier, controller 25 is connected to image processing circuit 19 for controlling image sensors 17 and 18 and for receiving the shape data of sewing needle 7 from image processing circuit 19.

Controller 25 is further connected to drive circuits 30, 31, and 32 for controlling LCD 20, sewing machine motor 12 and needle-swing pulse motor 13 to execute the sewing operation. A buzzer 34 for alerting purposes is further connected to controller 25 through drive circuit 33. The aforementioned connector 23 is also connected to controller 25.

As will be described through description of the operation of the above described configuration with reference to a flowchart, the software configuration, more specifically, the execution of needle status evaluation program of controller 25 provides automatic detection (evaluation) of presence of wear or deterioration such as bending, broken tip, and rounded tip of sewing needle 7.

Controller 25 captures images of sewing needle 7 at predetermined timing through image sensors 17 and 18 and extracts the shape data of the sewing needle 7 from the captured image by image processing circuit 19. Controller 25 obtains measurements of various portions of sewing needle 7 based on the shape data of sewing needle 7 and determines if any of the measurements are abnormal. Controller 25, when encountering an abnormality, displays a message on LCD 20 indicating to that effect with a ringing of buzzer 34.

To describe more specifically on abnormality evaluation, controller 25 determines occurrence of deformation of sewing needle 7 based on evaluation of the degree of bend in view of the overall shape of sewing needle 7; where as occurrence of rounded tip and broken tip is determined based on evaluation of the shape or the sharpness of the tip of sewing needle 7.

The operation of the above described configuration will be described hereinafter with reference to FIGS. 5A to 8. Flowchart given in FIG. 7 indicates the overall process flow of abnormality evaluation of sewing needle 7 executed by controller 25. Flowchart given in FIG. 8 elaborates steps S3 of flowchart given in FIG. 7. In the present exemplary embodiment, abnormality evaluation of sewing needle 7 is executed every time power of sewing machine 1 is turned on. The evaluation is further executed periodically, when cumulative sew time has exceeded a predetermined time interval of 10 hours, for example, or when cumulative stitch count has exceeded a predetermined stitch count of 10 thousand stitches, for example.

At step S1 of FIG. 7, images of sewing needle 74 attached to needle bar 6 is captured through image sensors 17 and 18 to obtain image data of sewing needle 7. Then, at step S2, image processing circuit 19 extracts (recognizes) the outline (shape) of sewing needle 7 from the obtained image data of sewing needle 7. Then, at step S3, sharpness and bending of the tip of sewing needle 7 is evaluated based on various measurements of sewing needle 7 measured from the extracted shape of sewing needle 7.

Flowchart given in FIG. 8 elaborates step S3. At step S11, the lowermost point of the extracted shape of sewing needle 7 is recognized as the tip of sewing needle 7. Then, at step S12, controller 25 looks up the data representing the angle of incline of sewing needle 7 based on the specified pattern (stitch type) and swing width. Based on the obtained angle of sewing needle 7, a corresponding preset center line O (refer to FIGS. 5B to 5D and FIGS. 6A to 6C) of sewing needle 7 is assumed.

FIG. 5A shows a bottom end of needle bar 6 and sewing needle 7 and FIGS. 5B to 5D provide an enlarged view of the shape of sewing needle 7 tip represented by reference symbol E at FIG. 5A. FIGS. 5B and 5D show sewing needle 7 stopped in a straight position with no incline (center baseline), and FIG. 5C shows sewing needle 7 stopped at incline θ to the left side of sewing needle 7 (left baseline). In the example shown in FIGS. 5B and 5D, center line O can be drawn that extends vertically from the tip of sewing needle 7 to the upper surface of needle plate 16. In the example shown in FIG. 5C, center line O inclined by angle θ can be drawn that extends from the tip of sewing needle 7. FIGS. 5B and 5C depicts the tip of sewing needle 7 maintaining its initial sharpness, and FIG. 5D depicts slight rounding observed at the tip of sewing needle 7 by wear.

At step S13, a determination is made as to whether or not width “b” of sewing needle 7 at height “a” (1 mm, for example) from the tip of sewing needle 7 is equal to or less than a predetermined value (0.5 mm, for example). If sewing needle 7 is inclined as depicted in FIG. 5C, width “b” can be obtained by plotting a point which resides on center line O and which is distanced by length “a” from the tip of sewing needle 7 and drawing a line which passes through the plotted point which is further orthogonal to center line O. The width of sewing needle 7 superimposed on the drawn line provides the required width “b”. The tip of sewing needle 7 is profiled such that the tip (lower end) has the least width and the width increases with distance from the tip. Thus, as the tip of sewing needle 7 wears and is rounded to some extent, width “b” of sewing needle 7 at height “a” from the tip of sewing needle 7 exceeds a predetermined value of 0.7 mm, for example, at some point in time as can be seen in FIG. 5D. The same is true if the tip of sewing needle is broken off.

The above described process at step S13 allows detection of rounded or broken tip of sewing needle 7. If width “b” of sewing needle 7 at height “a” from the tip of sewing needle 7 is determined to be equal to or less than a predetermined value (step S13: Yes), a determination that no tip rounding or tip breakage has occurred at the tip of sewing needle 7 and the control proceeds to step S15. As opposed to this, if width “b” of sewing needle 7 at height “a” from the tip of sewing needle 7 is determined to exceed the predetermined value (step S13: No), it is determined that tip rounding or tip breakage has occurred. Then at the following step S14, an alert is issued to notify a rounded tip or broken tip to prompt replacement of sewing needle 7. The alert is notified to the user through a message displayed on LCD 20 and a ringing of buzzer 34.

If no rounded tip or broken tip is encountered (step S13: Yes), determination is made at step S15 as to whether or not bending of sewing needle 7 has occurred by evaluating the overall shape of sewing needle 7. The occurrence of bend is determined through a process specifically described in FIGS. 6A to 6C. After shape (outline) extraction of sewing needle 7, multiple height measurements (3 in FIGS. 6A to 6C) is marked at predetermined spacing c (5 mm, for example) throughout the extent of sew needle 7 running from the tip to the base end. Then, lengths (X1 to X6 in FIGS. 6A to 6C) from center line O to the left and right edges of sewing needle 7 is measured to verify its symmetry, in other words, to verify that center line O passes through the center of sewing needle 7.

FIGS. 6A and 6B depict sewing needle 7 which is free of bend. FIG. 6B depicts sewing needle 7 halted with incline θ to the left side of sewing needle 7 (left baseline) and FIG. 6C provides an exaggerated depiction of a bent sewing needle 7. If sewing needle 7 is straight and is bend free, relation between widths X1 to X6 can be described as X1=X2, X3=X4, and X5=X6 as indicated in FIGS. 6A and 6B. If the above relation is true, a determination is made that sewing needle 7 is bend free (step S15: Yes) to terminate the control.

As opposed to this, if bend is observed in sewing needle 7 as can be seen in FIG. 6C, X1=X2, X3=X4, and X5=X6 are not met, and hence a determination is made that sewing needle is bent (step S15: No). Then, in the following step S16, an alert is issued to indicate a bend and prompt replacement of sewing needle 7. The alert is, as described earlier, notified to the user through a message displayed on LCD 20 and a ringing of buzzer 34.

The above described configuration automatically detects occurrence of sewing needle 7 abnormalities and noticeably alert the user that sewing needle 7 has suffered substantial wear that would require replacement. By seeing and hearing the alert, the user is given an opportunity to replace sewing needle 7 at an appropriate timing. Though not shown in FIG. 8, if abnormality is found in sewing needle 7, meaning that No determination is made at step S13 or step S15, controller 25 may prohibit start up of sewing machine motor 12. In such case, execution of sewing operation is allowed only after replacement of sewing needle 7 and after being verified that no abnormality is found through re-evaluation of sewing needle 7.

According to the above described exemplary embodiment, the shape of sewing needle 7 is extracted from the image data of sewing needle 7 captured by image sensors 17 and 18 and presence/absence of abnormalities in sewing needle 7 can be readily and reliably determined through evaluation of various measurements of sewing needle 7. More specifically, by evaluating the overall shape of sewing needle 7, presence/absence of bend in sewing needle 7 can be determined readily and reliably. Similarly by evaluating the shape of the tip of sewing needle 7, presence/absence of rounded tip or broken tip can be determined readily and reliably. If abnormalities are encountered, a noticeable alert is brought to user attention promptly through display on LCD 20 and ringing of buzzer.

Thus, as opposed to the conventional detector relying on the user in determining the need of sewing needle 7 replacement, the present disclosure provides automatic evaluation of the wear of sewing needle 7 without relying on visual recognition and decision by the user. Replacing sewing needle 7 in an appropriate time frame provides a favorable result of preventing trouble caused by a damaged sewing needle 7.

Further, since the present exemplary embodiment obtains multiple image data, the shape of sewing needle 7 can be extracted with greater accuracy. Especially when compared to images being captured from a single direction only, the present exemplary embodiment advantageously allows precise evaluation of bends occurring in various directions.

Image sensors 17 and 18 configured by CMOS (Complimentary Metal Oxide Semiconductor) or CCD (Charged Couple Device) are provided at 2 different locations of sewing machine 1 to allow compact and low cost implementation on sewing machine 1 and consequently keeping sewing machine 1 compact.

A second exemplary embodiment will be described with reference to FIGS. 9A to 13. Hardware configurations that are identical to the first embodiment will be represented by identical reference symbols and will not be shown or described in detail. The description will be given hereinafter on portions that differ from the first exemplary embodiment.

A sewing machine according to the second exemplary embodiment, as shown in FIG. 9A, comes with accessory of replacement needles of different thickness types (4, in the present exemplary embodiment) for selective attachment by the user. FIG. 9B is a chart showing thickness (width) A of sewing needles 7 identified by needle number. The thickness A is measured at 10 mm, for example, from the tip of sewing needle 7 as shown in FIG. 9B. In the present exemplary embodiment, 4 types of sewing needles 7 identified as needle numbers (needle no.) 9, 11, 14, 16 are provided which increase in thickness with needle number.

The 4 types of sewing needles 7 may be selectively used based on the type or thickness of the workpiece cloth when forming utility stitches. More specifically, needle no. 14 is used for “normal” cloth, needle no. 16 for “thick” cloth, needle no. 11 for “thin” cloth, and needle no. 9 for “extra thin” cloth.

Types of workpiece cloth categorized as “normal” may be: broadcloth, tafta, flannel, and gabardine; “thick” may be: denim, corduroy, and tweed; and “thin” may be: lawn, georgette, and polar. It is recommended to sew above types of cloth with appropriate type of sewing needle as exemplified above.

Embroidering, especially when using embroidery machine 22, involves multiplicity of stitches, and since embroidering in general is carried out on a single piece of cloth, it is desirable to use a thin needle, in this case, needle no. 11.

When sewing needle 7 of appropriate thickness is not used in sewing specific types or thickness of workpiece cloth, sewing needle 7 may bend or leave an oversized through hole that would impair the look of the finished product.

The present exemplary embodiment, being a modification of the first exemplary embodiment, primarily utilizes its software configuration (execution of needle status evaluation program) to extract the shape data of sewing needle 7 through image processing circuit 19 based on images of sewing needle 7 captured through image sensors 17 and 18. Then, based on the shape data of sewing needle 7, various measurements of sewing needle 7 are obtained and evaluated to determine the presence/absence of wears (deterioration) such as overall bending of sewing needle and rounded tip or broken tip that are, if found, brought to user attention.

Further, the software configuration of controller 25 detects the thickness and the type (needle no.) of sewing needle 7 attached, from the shape data of sewing needle 7. When in embroidery sewing mode, that is, when attachment of embroidery machine 22 through connector 23 is detected, controller determines whether or not the detected thickness of sewing needle 7 (needle no.) is appropriate (needle no. 11). If the detected sewing needle 7 is not appropriate, replacement of sewing needle 7 is prompted through an alert displayed on LCD 20 and ringing of buzzer 34.

Utility stitching in the present exemplary embodiment is carried out by selecting the desired utility pattern displayed on LCD 20 through user operation of touch panel 21 and selection of cloth thickness from the choice of “normal”, “thin”, and “thick” by depressing the corresponding selection key displayed on LCD 20 through touch panel 21.

Then, controller 25 determines whether or not the specified cloth thickness in the utility sewing mode and the detected thickness (needle no.) of sewing needle 7 are appropriate. If determined to be inappropriate, an alert is issued through display on LCD 20 and ringing of buzzer 34 to prompt replacement of sewing needle 7. Instead of specifying the thickness of the workpiece cloth, the user may alternatively be allowed to select the appropriate type of fabric of workpiece cloth from the exemplary types of fabric described earlier.

Flowchart given in FIG. 10 indicates the overall process flow of abnormality evaluation and thickness detection of sewing needle 7 executed by controller 25. Flowcharts given in FIG. 11 elaborates step S21 of FIG. 10 flowchart; FIG. 12 elaborates step S23 of FIG. 10 flowchart; and FIG. 13 elaborates step S25 of FIG. 10 flowchart.

That is, the process flows in the same way as in the first exemplary embodiment in which at step S1 of FIG. 10, controller 25 captures images of sewing needle 7 attached to needle bar 6 through image sensors 17 and 18 to obtain image data of sewing needle 7. Then, at step S2, image processing circuit 19 extracts (recognizes) the outline (shape) of sewing needle 7 from the obtained image data of sewing needle 7. Then, at step S3, sharpness and bending of the tip of sewing needle 7 is evaluated based on various measurements of sewing needle 7 measured from the extracted shape of sewing needle 7.

Then, at step S21, thickness (needle no.) of sewing needle 7 is detected from the shape data of sewing needle 7 extracted at step S2. The process is describe more specifically in FIG. 11, in which at step S31, thickness “A” is measured at 10 mm, for example, from the tip of sewing needle 7 as can be seen in FIG. 9A. Then, at step S32, thickness “A” is compared with preset thickness as exemplified in FIG. 9B and the needle no. that matches or that is in closest distance within a predetermined range from thickness A is obtained and displayed on LCD 20.

After obtaining the thickness (needle no.) of sewing needle 7 in the above described manner, the process returns to FIG. 10. At step S22, a determination is made as to whether or not the selected sewing mode is the embroidery sewing mode through detection of attachment of embroidery machine 22, where attachment of embroidery machine 22 indicates the embroidery sewing mode and if otherwise, the utility sewing mode. If in the embroidery sewing mode (step S22: Yes), the control proceeds to steps S23 to execute detection of sewing needle 7 under the embroidery sewing mode.

More specifically, at step S33 of FIG. 12, a determination is made as to whether or not the needle no. obtained at steps S21 (S32) is sewing needle 7 represented as needle no. 11 which is suitable for embroidering. If attachment of needle no. 11 is verified (step S33: Yes), the control is returned (terminated). If needle no. 11 is not attached (step S33: No), replacement of sewing needle 7 is prompted through an alert displayed on LCD 20 and ringing of buzzer 34.

Control is then, returned to FIG. 10 and if the current sewing mode is not the embroidery sewing mode, but is the utility sewing mode (step S22: No), a determination is made as to whether or not to execute utility sewing mode. If utility sewing is to be executed (step S24: Yes), the control proceeds to step S25 to execute detection of sewing needle under the utility sewing mode and if not (step S24: No), the control is terminated.

At step S25, detection of sewing needle 7 in the utility sewing mode is carried out by specifying the thickness of workpiece cloth from the selection of “normal”, “thin”, and “thick” through user operation of touch panel 21 at step S35 indicated in FIG. 13. As mentioned earlier, the user may alternatively be allowed select the appropriate type of fabric of workpiece cloth from the exemplary types of fabric through operation of touch panel 21. Then at step S36, a determination is made as to whether or not the needle no. of the attached sewing needle 7 selected at step S21 (S32) is appropriate for sewing the selected thickness of workpiece cloth.

As mentioned earlier, needle no. 11 or 9 is appropriate for “thin” cloth, needle no. 14 for “normal” cloth, and needle no. 16 for “thick” cloth. If the detected sewing needle 7 is not appropriate (step S36: No), replacement of sewing needle 7 is prompted through an alert displayed on LCD 20 and ringing of buzzer 34. If the detected sewing needle 7 is appropriate (step S36: Yes), the control is terminated.

According to the above described second exemplary embodiment, wear of sewing needle 7 is automatically evaluated without relying on visual recognition and decision of the user and thus prevents negative impact on the sewing operation originating from the deterioration of sewing needle 7. Further, since an alert is issued to replace sewing needle 7 when the thickness of the selected sewing needle 7 for use in the embroidery sewing mode is not appropriate for embroidery sewing operation, the risk of executing an embroidery sewing operation with an inappropriate sewing needle 7 thickness can be eliminated. The alert to prompt replacement of sewing needle 7 is issued when the thickness of sewing needle 7 is inappropriate for sewing the specified thickness of the workpiece cloth in utility sewing mode as well. Thus, the risk of executing a utility sewing operation with an inappropriate sewing needle 7 thickness can likewise be eliminated. The above configuration provides improved quality of the sewing operation.

FIGS. 14 and 15 indicate a third exemplary embodiment of the present disclosure, which differs from the first exemplary embodiment in the following respects. In the third exemplary embodiment, when starting the use of sewing needle 7, in other words, when sewing needle 7 is attached to needle bar 6 for the very first time, the image of sewing needle 7 is captured by image sensors 17 and 18. Then, the shape of sewing needle 7 is extracted based on the captured image data and the initially extracted shape data (initial shape data) is stored (registered) in memory (EEPROM 29) of controller 25.

Then, after starting the use of sewing needle 7, controller 25 captures images of sewing needle 7 by image sensors 17 and 18 at predetermined timings and extracts the shape data of sewing needle 7 from the captured images through image processing circuit 19. By comparing the shape data of sewing needle 7 with the initially extracted shape data stored in the memory of controller 25, absence/presence of bend in sewing needle 7, rounded tip, and broken tip is determined. If abnormalities are found, an alert is issued to that effect through display on LCD 20 and ringing of buzzer 34.

Flowchart given in FIG. 14 indicates the entire process flow of abnormality evaluation of sewing needle 7 executed by controller 25, and step S44 of the process flow is elaborated in FIG. 15. In step S41 of FIG. 14, the image of sewing needle 7 is captured by image sensors 17 and 18 from which the shape of sewing needle 7 is extracted by the captured image data and the initially extracted shape data is stored (registered) in memory of controller 25 as described earlier.

Then, at step S42, the image data of sewing needle 7 attached to needle bar 6 is captured by image sensors 17 and 18 after starting the use of the newly attached sewing needle 7. At step S43, the shape (outline) of sewing needle 7 is extracted (recognized) from the captured images through image processing circuit 19. At step S44, the extracted shape data of sewing needle 7 is compared with the initially extracted shape data of sewing needle 7 stored in the memory of controller 25 to evaluate the tip sharpness and tip bending of sewing needle 7.

More specifically, at step S51 of FIG. 15, the initially extracted shape data of the newly attached sewing needle 7 is compared with the current shape data of sewing needle 7 to verify whether the two data match (to verify whether the two data fall within a predetermined similarity threshold). If determined to be in conformity (step S51: Yes) the control is terminated since no abnormality is observed in sewing needle 7. If determined data do not match (step S51: No), a determination is made at step S52 as to whether or not the portion of sewing needle 7 failing to match the original status involves only the measurement in the height from the tip of sewing needle 7.

If the un-matching portion consists only of the height from the tip of sewing needle 7 (step S52: Yes), it can be determined that the abnormality comprises either a rounded tip or a broken tip. Thus, at step S53, an alert is issued to inform the user of a rounded tip or broken tip through a message displayed on LCD 20 and ringing of buzzer 34 to prompt replacement of sewing needle 7. If the un-matching portion does not consist only of the height from the tip of sewing needle 7 (step S52: No), the abnormality may be a bend or breakage. Thus, at step S54, an alert is issued to inform the user of a needle bend or needle breakage through a message displayed on LCD 20 and ringing of buzzer 34 to prompt replacement of sewing needle 7.

The above described third exemplary embodiment also extracts the shape data of sewing needle 7 from the image data of sewing needle 7 captured by image sensors 17 and 18 and compares the shape data with the initially extracted shape data of sewing needle 7 to readily and reliably determine the presence/absence of abnormalities in sewing needle 7. When an abnormality is encountered, the user is promptly and noticeably alerted through display on LCD 20 and ringing of buzzer 34.

Thus the third exemplary embodiment provides the favorable effects provided by the first exemplary embodiment. That is, as opposed to the conventional detector relying on the user in determining the need of sewing needle 7 replacement, the third exemplary embodiment also provides automatic evaluation of the wear of sewing needle 7 without relying on visual recognition and decision by the user. Replacing sewing needle 7 in an appropriate time frame, provides a favorable result of preventing trouble caused by wears of sewing needle 7.

The above described exemplary embodiments may be partially modified as follows.

The two image sensors 17 and 18 provided in the above described embodiments for capturing images of sewing needle 7 may be reduced to one or increased to three or more. The image sensor(s) may be relocated to the underside of head 5 and be oriented forwardly leftward from sewing needle 7 or may be placed on sewing machine bed 2, or any other locations that are capable of capturing images of sewing needle 7.

The images captured by the two or more image sensors may be synthesized to allow extraction of a three dimensional shape of sewing needle 7. Such configuration allows even more accurate evaluation of bending of sewing needle 7.

Abnormalities of sewing needle 7 may be informed to the user by voice messages, illumination or flickering of a lamp, or combination of such approaches instead of displaying messages on LCD 20 and ringing of buzzer 34.

Parameters such as various measurements of sewing needle 7, threshold values and the types (thickness) of sewing needle indicated in the second exemplary embodiment is merely exemplary and may be modified as required.

The above exemplary embodiments have been described by way of a sewing machine allowing attachment of embroidery machine 22 and thus, being capable of embroidering; however, the present disclosure may also be applied to sewing machines that are not provided with embroidery machine 22.

The initial shape data of sewing needle 7 which was obtained by actually capturing the image of the newly attached sewing needle 7 in the third exemplary embodiment may instead be provided as a preset data or template by the manufacturer to be employed as comparative data.

While various features have been described in conjunction with the examples outlined above, various alternatives, modifications, variations, and/or improvements of those features and/or examples may be possible. Accordingly, the examples, as set forth above, are intended to be illustrative. Various changes may be made without departing from the broad spirit and scope of the underlying principles.

Claims

1. A sewing machine provided with a needle bar having a sewing needle interchangeably attached to its lower end, comprising:

an imaging element that captures images of the sewing needle;

an extractor that extracts a shape of the sewing needle from the images of the sewing needle captured by the imaging element;

an abnormality determiner that determines presence/absence of abnormalities in measurements of the sewing needle based on the shape of the sewing needle extracted by the extractor; and

an abnormality alerter that alerts the presence of abnormalities determined by the determiner.

2. A sewing machine provided with a needle bar having a sewing needle interchangeably attached to its lower end, comprising:

an imaging element that captures images of the sewing needle;

an extractor that extracts a shape of the sewing needle from the images of the sewing needle captured by the imaging element;

a storage that pre-stores an initial shape of the sewing needle;

an abnormality determiner that determines presence/absence of abnormalities in the shape of the sewing needle extracted by the extractor by comparing with the initial shape pre-stored in the storage; and

an abnormality alerter that alerts the presence of abnormalities determined by the determiner.

3. The sewing machine of claim 1, wherein the abnormality determiner determines presence/absence of a bend or a breakage in the sewing needle by evaluating an overall shape of the sewing needle.

4. The sewing machine of claim 2, wherein the abnormality determiner determines presence/absence of a bend or a breakage in the sewing needle by evaluating an overall shape of the sewing needle.

5. The sewing machine of claim 1, wherein the abnormality determiner determines presence/absence of a rounded tip or a broken tip in the sewing needle by evaluating a tip shape of the sewing needle.

6. The sewing machine of claim 2, wherein the abnormality determiner determines presence/absence of a rounded tip or a broken tip in the sewing needle by evaluating a tip shape of the sewing needle.

7. The sewing machine of claim 1, further being configured to allow interchangeable mode switching between a utility sewing mode and an embroidery sewing mode, wherein the needle bar is configured to allow interchangeable attachment of sewing needles of different thickness, the sewing machine further comprising a thickness detector that detects a thickness of sewing needle based on the shape of the sewing needle extracted by the extractor; a thickness evaluator that, when in the embroidery sewing mode, evaluates whether or not the thickness of the sewing needle detected by the thickness detector is appropriate for embroidery sewing; and a first misuse alerter that prompts replacement of the sewing needle when evaluated by the thickness evaluator that the thickness of the sewing needle is inappropriate for embroidery sewing.

8. The sewing machine of claim 2, further being configured to allow interchangeable mode switching between a utility sewing mode and an embroidery sewing mode, wherein the needle bar is configured to allow interchangeable attachment of sewing needles of different thickness, the sewing machine further comprising a thickness detector that detects a thickness of sewing needle based on the shape of the sewing needle extracted by the extractor; a thickness evaluator that, when in the embroidery sewing mode, evaluates whether or not the thickness of the sewing needle detected by the thickness detector is appropriate for embroidery sewing; and a first misuse alerter that prompts replacement of the sewing needle when evaluated by the thickness evaluator that the thickness of the sewing needle is inappropriate for embroidery sewing.

9. The sewing machine of claim 1, wherein the needle bar allows interchangeable attachment of sewing needles of different thickness, the sewing machine further comprising a specifier that allows specification of a type or a thickness of a workpiece cloth to be sewn, a thickness detector that detects a thickness of sewing needle based on the shape of the sewing needle extracted by the extractor, a conformity evaluator that evaluates whether or not the thickness of the sewing needle detected by the thickness detector conforms to the type or the thickness of the workpiece cloth specified by the specifier; and a second misuse alerter that prompts replacement of the sewing needle when evaluated by the conformity evaluator that the thickness of the sewing needle does not conform to the type or the thickness of the workpiece cloth.

10. The sewing machine of claim 2, wherein the needle bar allows interchangeable attachment of sewing needles of different thickness, the sewing machine further comprising a specifier that allows specification of a type or a thickness of a workpiece cloth to be sewn, a thickness detector that detects a thickness of sewing needle based on the shape of the sewing needle extracted by the extractor, a conformity evaluator that evaluates whether or not the thickness of the sewing needle detected by the thickness detector conforms to the type or the thickness of the workpiece cloth specified by the specifier; and a second misuse alerter that prompts replacement of the sewing needle when evaluated by the conformity evaluator that the thickness of the sewing needle does not conform to the type or the thickness of the workpiece cloth.

11. The sewing machine of claim 1, wherein the imaging element is provided at a plurality of different locations of the sewing machine.

12. The sewing machine of claim 2, wherein the imaging element is provided at a plurality of different locations of the sewing machine.

13. The sewing machine of claim 1, wherein the imaging element comprises a complimentary metal oxide semiconductor image sensor or a charge coupled device image sensor.

14. The sewing machine of claim 2, wherein the imaging element comprises a complimentary metal oxide semiconductor image sensor or a charge coupled device image sensor.

15. The sewing machine of claim 1, further comprising a liquid crystal display provided on a front face of the sewing machine, wherein the abnormality alerter issues alerts through display of message information on the liquid crystal display.

16. The sewing machine of claim 2, further comprising a liquid crystal display provided on a front face of the sewing machine, wherein the abnormality alerter issues alerts through display of message information on the liquid crystal display.

17. A computer readable medium storing a needle status evaluation program that automatically evaluates wear of a sewing needle for use in a sewing machine provided with a needle bar having a sewing needle interchangeably attached to its lower end, the needle status evaluation program stored in the computer readable medium, comprising:

instructions for capturing images of the sewing needle with an imaging element;

instructions for extracting a shape of the sewing needle from the images of the sewing needle captured;

instructions for determining presence/absence of abnormalities in measurements of the sewing needle based on the shape of the sewing needle extracted; and

instructions for alerting the presence of abnormalities determined.

18. The medium of claim 17, for use in the sewing machine further configured to allow interchangeable mode switching between a utility sewing mode and an embroidery sewing mode, and the needle bar is configured to allow interchangeable attachment of sewing needles of different thickness, the needle status evaluation program further comprising instructions for detecting a thickness of sewing needle based on the shape of the sewing needle extracted, instructions for evaluating, when in the embroidery sewing mode, whether or not the thickness of the sewing needle detected is appropriate for embroidery sewing, and instructions for prompting replacement of the sewing needle when evaluated that the thickness of the sewing needle is inappropriate for embroidery sewing.

19. The medium of claim 17, for use in the sewing machine, wherein the needle bar is configured to allow interchangeable attachment of sewing needles of different thickness, the needle status evaluation program further comprising instructions for specifying a type or a thickness of a workpiece cloth to be sewn, instructions for detecting a thickness of sewing needle based on the shape of the sewing needle extracted, instructions for evaluating whether or not the thickness of the sewing needle detected conforms to the type or the thickness of the workpiece cloth specified; and instructions for prompting replacement of the sewing needle when evaluated that the thickness of the sewing needle does not conform to the type or the thickness of the workpiece cloth.