EP1359242A1

EP1359242A1 - Linking method and linking apparatus

Info

Publication number: EP1359242A1
Application number: EP03009930A
Authority: EP
Inventors: Sadao Kawamura; Akira Ishii; Takahiro Wada; Naomasa Ochi; Kimio Takeda
Original assignee: Dan Co Ltd
Current assignee: Dan Co Ltd
Priority date: 2002-05-01
Filing date: 2003-04-30
Publication date: 2003-11-05
Anticipated expiration: 2023-04-30
Also published as: KR100529402B1; JP3637329B2; DE60306025D1; ES2263873T3; EP1359242B1; KR20030086906A; DE60306025T2; JP2003320184A

Abstract

There are provided a linking method and a linking apparatus capable of automatically carrying out operation of piercing a point needle to an overlocking loop knitted at a knitting fabric swiftly and accurately to thereby solidly link the knitting fabric. By using a main body mechanism (100) having an inserting member (110) for being inserted through a sock to expand, a needle piercing mechanism (120), a CCD camera (140) and a computer (150), detecting initial overlocking loops simultaneously on a front side and a rear side (S108), thereafter detecting a position of the overlocking loop (S112), positioning the point needle (S114) and piercing the point needle (S116) are repeated, when the point needles have finished piercing to all of the overlocking loops, the point needles are returned to initial positions (S120). When the operation has been finished with both faces of the knitting fabric, the inserting member (110) is drawn (S122), the sock W is moved to one of the point needles (S124) and overlocked (S126). Further, a semiautomatic processing by a tacking needle or an automatic processing using an inserting member having converged both ends can also be carried out.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a linking method and a linking apparatus for overlocking a knitting fabric, particularly to a linking method and a linking apparatus for overlocking a knitting fabric by, for example, automatically piercing a point needle through an overlocking loop of the linking fabric.

2. Description of the Prior Art

Knitting fabric for constituting a material of a knitted product is knitted with a loose course comprising a knitted loop knitted to be larger than other knitted loop (hereinafter, simply referred to as overlocking loop) such that the product is correctly overlocked into prescribed size and shape when the knitted loop is overlocked.
Therefore, conventionally, overlocking has been carried out by piercing a point needle to each of overlocking loops constituting the loose course by looking through a knitting fabric after an operator pulled to widen the knitting fabric by the hand.
The operation has been carried out similarly also in the case of circular knitting fabric knitted in a cylindrical shape such as a sock. First, the operator pulls to widen the circular knitting fabric by putting the both hands into an opening portion of the circular knitting fabric, confirms the overlocking loop by looking through the knitting fabric on the depth side in view from the operator, pierces the point needle through the overlocking loop and thereafter, carries out the operation similarly also with regard to the knitting fabric on the operator's side to pierce the same point needle to the overlocking loops to be overlocked to thereby carry out overlocking operation.
However, it has been very difficult to pierce the point needle through the overlocking loop since the overlocking loop is only formed to be more or less larger than an ordinary knitted loop. Particularly, with regard to the circular knitting fabric, it is difficult to pull to widen the knitting fabric on the operator's side after piercing the point needle through the knitting fabric on the depth side and therefore, the problem is significantly posed. As a result, a long period of time is taken for carrying out the overlocking operation and further, a drawback of overlocking the knitting fabric while being deviated from the overlocking loop is brought about to result in a deterioration in the yield of the product.
Therefore, as is disclosed in JP-A-11-207061 or JP-A-11-207062, there has been developed a linking apparatus including an inserting member for expanding a knitting fabric by being inserted to an inner portion of a circular knitting fabric having an overlocking loop, image picking up means for picking up an image of the overlocking loop of the knitting fabric expanded by the inserting member, overlocking loop position detecting means for detecting a position of the overlocking loop by subjecting the image picked up by the image picking up means to an image processing, means for corresponding a point needle to the position of the overlocking loop detected by the overlocking loop position detecting means, means for piercing the point needle corresponding to each overlocking loop therethrough, and a sewing machine mechanism for overlocking the knitting fabric based on the pierced point needle, in which the operation of detecting the position of the overlocking loop of the knitting fabric, positioning the point needle corresponding to the detected overlocking loop and piercing the point needle corresponding to the detected overlocking loop therethrough is repeated and after piercing the point needle through each overlocking loop of the knitting fabric, the knitting fabric is overlocked by the sewing machine mechanism.
However, the conventional linking apparatus poses the following problem.
Since overlocking loops at both end portions (hereinafter, referred to as V points) are disposed at side faces of the inserting member after inserting the inserting member through the sock and therefore, it is difficult to detect the V points by the image processing and it is also difficult to pierce the point needle automatically. Therefore, the V point needles are pierced through the V points by manual operation and an initial overlocking loop is determined by a hole having a predetermined area on an inner side of the V point by a predetermined distance, positions of overlocking loops are successively detected toward the inner side and the corresponding point needles are pierced therethrough. However, a vicinity of the V point is near to a position of folding back cloth and a position or a size thereof is liable to change depending on an attaching condition. Particularly, with regard to a front side, there is a large knitted loop referred to as a gore line of a toe side whereby also the vicinity of the overlocking loop is constituted by a complicated knitted loop structure. Therefore, there poses a problem that in detecting the initial overlocking loop by the image processing, the initial overlocking loop is not detected to thereby need assistance of the operator, or the initial overlocking loop is erroneously detected and the knitting fabric is overlocked while being deviated from the overlocking loop.

SUMMARY OF THE INVENTION

Therefore, an object of the invention is to resolve the problem and provide a linking method and a linking apparatus capable of resolving the problem and solidly linking knitting fabric by swiftly and accurately piercing a point needle through an overlocking loop knitted at the knitting fabric.
According to a first aspect of the invention, there is provided a linking method comprising a step of expanding a knitting fabric in a state of opposing linking object portions thereof, a step of picking up an image of the expanded knitting fabric, a step of detecting a position of an overlocking loop from the picked-up image, a step of positioning a point needle corresponding to the detected position of the overlocking loop thereto, a step of piercing the corresponding point needle through the detected overlocking loop, and a step of overlocking the knitting fabric based on the point needle pierced through each of the overlocking loops of the knitting fabric, further comprising a step of setting a detection reference line of an initial overlocking loop at a vicinity of an end portion of the knitting fabric, a step of detecting a start overlocking loop on an inner side of the end portion of the knitting fabric by a predetermined distance, a step of tracking the overlocking loop from the detected start overlocking loop toward the set detection reference line, and a step of determining the initial overlocking loop by a detected overlocking loop when a position of the detected overlocking loop falls to be equal to or smaller than the predetermined distance relative to the set detection reference line by tracking the overlocking loop.
According to the invention, the start overlocking loop is determined by detecting the overlocking loop on the inner side of the end portion of the knitting fabric by the predetermined distance, the initial overlocking loop is determined by tracking the overlocking loop from the start overlocking loop toward the end portion of the knitting fabric and therefore, the knitting fabric can solidly be linked by swiftly and accurately piercing the point needle through the overlocking loop by restraining nondetection or erroneous detection of the initial overlocking loop.
According to a second aspect of the invention, there is provided the linking method according to the first aspect, wherein the step of detecting the start overlocking loop comprises a step of detecting a hole having an area equal to or larger than a predetermined area by setting a predetermined region on the inner side of the end portion of the knitting fabric by the predetermined distance, a step of sampling a hole having a maximum area in the detected hole, a step of comparing areas of a hole on an upper side and a hole on a lower side in holes contiguous to either of left and right sides of the sampled hole having the largest area, a step of determining an overlocking loop by the hole on the upper side when the area of the hole on the upper side is larger than the area of the hole on the lower side, and a step of determining the overlocking loop by the detected hole having the largest area when the area of the hole on the lower side is larger than the area of the hole on the upper side.
According to the invention, in detecting the start overlocking loop for detecting the initial overlocking loop, based on a property of a knitted loop, the overlocking loop is determined by sampling the hole having the largest area from the detected hole having the area equal to or larger than the predetermined area and comparing the areas of the hole on the upper side and the hole on the lower side of either of the left side and the right side contiguous to the hole and therefore, the start overlocking loop can accurately be determined and the knitting fabric can solidly be linked by piercing the point needle to the overlocking loop swiftly and accurately by further restraining nondetection or erroneous detection of the initial overlocking loop.
According to a third aspect of the invention, there is provided the linking method according to the first aspect or the second aspect, wherein the step of setting the detection reference line of the initial overlocking loop comprises a step of detecting a hole having an area equal to or larger than a predetermined area by setting a predetermined region at a vicinity of the end portion of the knitting fabric, a step of selecting a hole most proximate to the end portion of the knitting fabric in the detected hole, and a step of setting the detecting reference line of the initial overlocking loop from a position of the selected hole.
According to the invention, the hole having the area equal to or larger than the predetermined area is detected at a vicinity of the end portion of the knitting fabric, the detection reference line of the initial overlocking loop is set from a position of the hole most proximate to the end portion of the knitting fabric and therefore, even when detecting the initial overlocking loop on the front side having a large knitted loop referred to as a gore line at the toe portion, the knitting fabric can solidly be linked by swiftly and accurately piercing the point needle through the overlocking loop by restraining nondetection or erroneous detection of the initial overlocking loop.
According to a fourth aspect of the invention, there is provided a linking apparatus comprising knitting fabric expanding means for expanding a knitting fabric in a state of opposing linking object portions thereof, image picking up means for picking up an image of the knitting fabric expanded by the knitting fabric expanding means, overlocking loop position detecting means for detecting a position of an overlocking loop an image of which is picked up by the image picking up means, point needle positioning means for positioning a point needle corresponding to the position of the overlocking loop detected by the overlocking loop position detecting means thereto, point needle piercing means for piercing the corresponding point needle through the detected overlocking loop, and overlocking means for overlocking the knitting fabric based on the point needle pierced through each of the overlocking loops of the knitting fabric by the point needle piercing means, further comprising detection reference line setting means for setting a detection reference line of an initial overlocking loop at a vicinity of an end portion of the knitting fabric, start overlocking loop detecting means for detecting a start overlocking loop on an inner side of the end portion of the knitting fabric by a predetermined distance, overlocking loop tracking means for tracking the overlocking loop from the detected start overlocking loop toward the set detection reference line, and initial overlocking loop detecting means for determining an initial overlocking loop by a detected overlocking loop when a position of the overlocking loop detected by the overlocking loop tracking means falls to be equal to or smaller than the predetermined distance relative to the set detection reference line.
According to the invention, the start overlocking loop is determined by detecting the overlocking loop on the inner side of the end portion of the knitting fabric by the predetermined distance, the initial overlocking loop is determined by tracking the overlocking loop from the start overlocking loop toward the end portion of the knitting fabric and therefore, the knitting fabric can solidly be linked by swiftly and accurately piercing the point needle through the overlocking loop by restraining nondetection or erroneous detection of the initial overlocking loop.
According to a fifth aspect of the invention, there is provided the linking apparatus according to the fourth aspect, wherein the start overlocking loop detecting means comprises detecting means for detecting a hole having an area equal to or larger than a predetermined area by setting a predetermined region on the inner side of the end portion of the knitting fabric by the predetermined distance, sampling means for sampling a hole having a largest area in the detected hole, comparing means for comparing areas of a hole on an upper side and a hole on a lower side in a hole contiguous to either of a left side and a right side of the detected hole having the largest area, and determining means for determining an overlocking loop by the hole on the upper side when the area of the hole on the upper side is larger than the area of the hole on the lower side and determining the overlocking loop by the detected hole having the largest are when the area of the hole on the lower side is larger than the area of the hole on the upper side.
According to the invention, in detecting the start overlocking loop for detecting the initial overlocking loop, based on the property of the knitted loop, the overlocking loop is determined by sampling the hole having the largest area from the detected hole having the area equal to or larger than the predetermined area and comparing the areas of the hole on the upper side and the hole on the lower side of either of the left side and the right side contiguous to the hole and therefore, the start overlocking loop can accurately be determined and the knitting fabric can solidly be linked by swiftly and accurately piercing the point needle through the overlocking loop by further restraining nondetection or erroneous detection of the initial starting loop.
According to a sixth aspect of the invention, there is provided the linking apparatus according to the fourth aspect or the fifth aspect, wherein the detection reference line setting means comprises detecting means for detecting the hole having the area equal to or larger than the predetermined area by setting the predetermined region at the end portion of the knitting fabric, selecting means for selecting a hole most proximate to the end portion of the knitting fabric in the detected hole, and setting means for setting the detection reference line of the initial overlocking loop from a position of the selected hole.
According to the invention, the hole having the area equal to or larger than the predetermined area is detected at a vicinity of the end portion of the knitting fabric, the detection reference line of the initial locking loop is set from the position of the hole most proximate to the end portion of the knitting fabric and therefore, even when detecting the initial overlocking loop on the front side having the large knitted loop referred to as the gore line at the toe portion, the knitting fabric can solidly be linked by swiftly and accurately piercing the point needle through the overlocking loop by restraining nondetection or erroneous detection of the initial overlocking loop.
The above-described object, other object, characteristics and advantages of the invention will become further apparent from a following detailed explanation of embodiments described in reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an outline constitution view of a main body mechanism according to an embodiment of a linking apparatus of the invention;
Fig. 2 is a view illustrating a point needle;
Fig. 3 is a plane view of a needle piercing mechanism;
Fig. 4 is a side view of the needle piercing mechanism;
Fig. 5 is an operational flowchart according to a first embodiment (V point manually processing type) of a linking apparatus of the invention;
Fig. 6 is an operational flowchart according to a second embodiment (semiautomatic type) of a linking apparatus of the invention;
Fig. 7 is an operational flowchart according to a third embodiment (automatic type) of a linking apparatus of the invention;
Fig. 8 is an operational flowchart according to a fourth embodiment (single needle type) of a linking apparatus of the invention;
Fig. 9 is a processing flowchart according to an embodiment of a processing of detecting a position of an overlocking loop;
Fig. 10 is a processing flowchart according to an embodiment of a processing of detecting a start overlocking loop;
Fig. 11 is a processing flowchart according to an embodiment of a processing of detecting a front side initial overlocking loop;
Fig. 12 is a processing flowchart according to an embodiment of a processing of detecting a rear side initial overlocking loop;
Fig. 13 is a processing flowchart according to an embodiment of a processing of positioning a point needle;
Fig. 14 is a processing flowchart according to an embodiment of a processing of returning a needle;
Fig. 15 is a processing flowchart according to an embodiment of a partially expanding mechanism;
Fig. 16 shows an example of an image of an ordinary overlocking loop;
Fig. 17 is an explanatory view of a method of directly detecting an overlocking loop;
Fig. 18 is an explanatory view of a method of finely detecting an overlocking loop;
Fig. 19 shows an example of an image of a front side initial overlocking loop;
Fig. 20 shows an example of an image of a rear side initial overlocking loop;
Fig. 21 is an explanatory view of a region of detecting a start overlocking loop;
Fig. 22 is an explanatory view of a processing of detecting a start overlocking loop;
Fig. 23 is an explanatory view of a processing of determining an overlocking loop;
Figs. 24A, 24B and 24C show an example of an image processing of a locking loop position detecting processing;
Figs. 25A, 25B, 25C and 25D show an example of an image processing of a processing of detecting an initial overlocking loop;
Figs. 26A and 26B are explanatory views of a jig for hanging a toe of a sock;
Fig. 27 is an explanatory view of a tacking needle for a semiautomatic processing;
Fig. 28 is an explanatory view of a both end converging inserting member; and
Fig. 29 is a conceptual view of a partially expanding mechanism.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1 is an outline constitution of a main body mechanism according to an embodiment of a linking apparatus of the invention. In the drawing, a main body mechanism 100 of a linking apparatus comprises an inserting member 110 for inserting a sock W to expand, a needle piercing mechanism 120 for piercing a point needle through an overlocking loop K of the expanded sock W, a CCD camera 140 for picking up an image of the overlocking loop K, a computer 150 including an image processing portion for inputting an image signal from the CCD camera 140 and carrying out an image processing to detect a position of the overlocking loop K and a mechanism control portion for controlling the main body mechanism, a sequencer 160 for controlling the needle piercing mechanism 120 by receiving a control signal from the computer 150, and a driver 170 for driving respective actuators of the needle piercing mechanism 120 by receiving a control signal from the sequencer 160.
The inserting member 110 is provided with a constant thickness and provided with a width for pertinently expanding the stock W in a left and right direction when inserting the stock W. Further, the inserting member 110 includes fixing pieces 112a and 112b for expanding the sock W pertinently in an up and down direction to fix when inserting the sock W. Thereby, the overlocking loop K of the sock W is pertinently expanded in the up and down direction and in the left and right direction and therefore, a position of the overlocking loop K can automatically be detected by subjecting the image picked up by the CCD camera 140 to the image processing by the computer 150.
The inserting member 110 also serves as an illuminating apparatus when the image of the overlocking loop K is picked up by the CCD camera and EL panels are attached to both faces of the inserting member 110 (not illustrated). Thereby, a hole of a knitted loop of the sock W is caught as a bright image by the CCD camera 140 and a fiber portion thereof is caught as a dark image thereby. In this way, by illuminating from a rear side of the sock W relative to the CCD camera 140 and detecting transmitted light by the CCD camera 140, the hole of the overlocking loop K can be caught with excellent contrast. Further, the illumination is not limited to the EL panel but may use a constitution aligned with LEDs or electric lamps and the illumination may naturally be carried out by using a light guide by fiber or a light guiding plate. Further, even when other illuminating method is used, it is preferable for catching the hole of the overlocking loop K with excellent contrast to illuminate from the rear side of the sock W relative to the CCD camera 140 and detect the transmitted light by the CCD camera 140.
Fig. 2 shows an outline constitution of a point needle for overlocking. Point needles 132 need to align at predetermined intervals for overlocking by a sewing machine mechanism (not illustrated) and are aligned in a needle box 130 having grooves at predetermined intervals as illustrated. Further, special V point needles 134 for piercing through the overlocking loops K at the both end portions of the sock W are provided at both ends thereof and a manually set previously to the overlocking loops K at the both ends. The V point needles 134 are arranged in a state of being movable in the left and right direction during a processing of piercing the point needles, locked to the needle box 130 at a time point of finishing to pierce all of the point needles 132 through the respective overlocking loops K of the sock W and delivered to the sewing machine mechanism.
Fig. 3 and Fig. 4 show an outline constitution of the needle piercing mechanism 120. As shown by the drawings, the needle piercing mechanism 120 includes a base 122, the needle box 130 fixed above the base 122 and a needle extruding mechanism 124 fixed above the base 122.
The needle extruding mechanism 124 includes a feed mechanism 126 for moving in accordance with the interval of the point needle 132 of the needle box 130 and selecting the point needle 132 to be extruded and an actuator 128 for extruding the selected point needle 132 to pierce through the overlocking loop K of the sock W. Although the feed mechanism 126 can be formed by an NC apparatus using a ball screw or the like and the actuator 128 can be formed by using a pneumatic actuator or a solenoid, further simply and conveniently, the actuator 128 may be driven by a spring, the feed mechanism 126 may be provided with a plate for locking extrusion of the needle and the point needles 132 may be extruded successively by drawing away the plates at constant intervals.
The base 122 of the needle piercing mechanism 120 can be mounted above a table (not illustrated) capable of positioning two-dimensionally in the up and down direction and in the left and right direction and the point needle 132 to be extruded can be positioned to the overlocking loop K of the sock W based on an instruction from the sequencer 160.
Further, the CCD camera 140 is mounted to the needle extruding mechanism 124 and moved along with the needle extruding mechanism 124. A center of a field of view of the CCD camera 140 is substantially made to coincide with a position of a surface of the sock W to be pierced with the point needle 132 extruded by the actuator 128. By bringing a center of the overlocking loop K of the sock W substantially to the center of the CCD camera 140 thereby, the corresponding point needle 132 can be pierced through the corresponding overlocking loop K and coordinate transformation is facilitated.
Equivalent ones of the needle piercing mechanisms 120 and the CCD cameras 140 are provided on both sides of the surface and the rear face to carry out operation of detecting the overlocking loops K and piercing the point needles 132 therethrough independently from each other for respectives of the front side and the rear side and when the operation of piercing all of the point needles 132 has been finished, the needle piercing mechanism 120 are returned to initial positions, positions of the needles on the front side and the rear side are made to coincide with each other and the inserting member 110 is drawn out. In this case, since the point needles 132 are pressed to the inserting member 110 by air pressure or the like, the sock W is not detached from the needles and the needles on the front side and the needles on the rear side are butted together. Finally, the sock W is moved to one side and overlocked by the sewing machine mechanism.
Although according to the embodiment, an explanation has been given such that the needle piercing mechanisms 120 use the point needles 132 on both sides of the front side and the rear sides to butt together, a needle on a side opposed to the point needle 132 for finally carrying out the overlocking operation may simply be a guide and may be of a sheath-like shape for coupling with the point needle 132 when butted to the point needle 132.
Further, it is not necessarily needed to provide the needle piercing mechanisms 120 on the both sides but the needle piercing mechanism 120 may be provided only on, for example, the front side, slits may be provided at portions of the inserting member 110 for piercing the point needles after piercing all of the point needles 132 through the respective overlocking loops K on the front side by dividing the inserting member 110 in the up and down direction, the positions of the overlocking loops on the rear side may be detected by the CCD camera 140 on the rear side, the positions of the corresponding point needles 132 of the needle piercing mechanism 120 on the front side may be made to coincide with the overlocking loops K on the rear side and the point needles 132 may be pierced therethrough completely to the rear side.
Next, an explanation will be given of an overlocking loop position detecting processing for detecting a position of an overlocking loop by subjecting an image of a knitted loop picked up by the CCD camera 140 to image processing.
Fig. 9 shows an example of a processing flow of an overlocking loop position detecting processing. As shown by the drawing, an image is inputted from the CCD camera 140 (S184), a predetermined detecting region is set (S186), and the inputted image is binarized (S188).
A threshold of the binarization is determined by using a determining analysis method (so-to-speak Ohtsu's method) of calculating a concentration histogram of the image in a predetermined region and selecting a threshold maximizing a dispersion between classes when the calculated concentration histogram is divided into two classes. This is because according to a P tile method of determining a threshold in which a rate of a pixel in the binarized image becomes P, when the cloth is excessively loosened or pulled, in order to make an area ratio constant, knitted loops are made continuous or the knitted loop is crushed and because even a mode method of finding a valley of the concentration histogram to constitute a threshold, poses a problem that when the cloth is loosed and the bimodality of the concentration histogram is lost, the threshold cannot be calculated and in the case of the determining analysis method, even when the bimodality is lost, the threshold can automatically be determined.
Further, as the threshold of the binarization, when an illuminating condition is stabilized, a fixed threshold may naturally be used. Further, although an explanation is omitted with regard to a pretreatment of the inputted image, it is preferable to remove noise by smoothing or the like before the binarization.
Next, the binarized image is labeled and a hole having a predetermined area or larger is detected (S190). Further, the position of the overlocking loop is predicted as mentioned later (S192), the overlocking loop is determined by a gravitational center of a label most proximate to the predicted position (S194), it is determined whether the overlocking loop is a correct one from a distance to the predicted position (S196), and the position is transformed into mechanical system position coordinate from the gravitational center of the detected overlocking loop (S198).
Fig. 16 shows an example of an image of an ordinary overlocking loop picked up by the CCD camera 140. As shown by the drawing, the overlocking loop is knitted to be larger than other knitted loop to facilitate to differentiate therefrom and in view of the structure, a knitted loop paired with the overlocking loop becomes also larger. Both of them do not become smaller than other knitted loop although a large or small relationship of areas of the overlocking loop and the knitted loop paired therewith is changed by the sock. Hence, the overlocking loop is detected by utilizing the structural characteristic that the overlocking loop and the knitted loop paired therewith become larger than other knitted loop.
Threads are intertwined at a knitted loop and therefore, the knitted loop is provided with a property that even when force is exerted to a certain point, the force effects influence widely at a surrounding thereof, a change of the knitted loop becomes smooth as a whole and a pitch of the overlocking loop becomes substantially constant.
Hence, when a basic X pitch is constituted by dividing a lateral width of the sock W expanded by the inserting member 110 by a number of the overlocking loops and the overlocking loops of the sock W are set substantially horizontally, a next overlocking loop position can be predicted from a known overlocking loop position by the following equation: |next overlocking loop predicted X position| = |known overlocking loop X position| + |basic X pitch|
Therefore, as shown by Fig. 17, a knitted loop most proximate to the predicted position can be detected as a next overlocking loop. Here, a shape of a knitted loop is proximate to an elliptical shape and therefore, the position of the knitted loop seems to be a gravitational center of the knitted loop and therefore, the gravitational center of the knitted loop most proximate to the predicated position is defined as the overlocking loop position (which is referred to as a direct detecting method).
However, the loops may be deformed in the up and down direction and a possibility of erroneous detecting is increased only by the above-described detecting method. Hence, as shown by Fig. 18, a method of finely detecting the gravitational center by utilizing the knitted loop paired with the overlocking loop (which is referred to a finely detecting method) may also be used. In this case, the next knitted loop position can be predicted from the known knitted loop position by the following equation: |next knitted loop predicted X position| = |known knitted loop X position| + |1/2 basic X pitch| |next knitted loop predicted Y position| = |known knitted loop Y position| ± |basic Y pitch|
Ordinary overlocking loops are aligned comparatively regularly except at vicinities of the both end portions and therefore, in this case, first, the overlocking loop is calculated by the direct detecting method, the predicted position and the detected gravitational center are compared, when a distance therebetween is equal to or smaller than a predetermined distance, the overlocking loop is determined and when the distance is equal to or larger than the predetermined distance, the overlocking loop is detected again by the finely detecting method. Thereby, the overlocking loop can efficiently be detected and a processing time period thereof can be shortened.
Figs. 24A, 24B and 24C show an example of detecting a position of an overlocking loop by the above-described processing. Fig. 24A shows a set detecting region, Fig. 24B shows a result of carrying out labeling processing at the detecting region and Fig. 24C shows a result of detecting a position of an overlocking loop from a gravitational center of a label most proximate to a predicted position.
Although according to the above-described embodiment, the processing of predicting the next overlocking loop position and constituting the overlocking loop by the gravitational center of the label most proximate thereto is used, the next overlocking loop may be detected by not using predicted information but tracking a label contiguous to the known overlocking loop and the position of the next overlocking loop may be constituted by a gravitational center thereof.
Next, a processing of detecting an initial overlocking loop will be described.
A knitted loop which is mostly difficult to detect in detecting overlocking loops is an initial overlocking loop. The initial overlocking loop is an overlocking loop most proximate to the V point. Fig. 19 shows an example of an image of an initial overlocking loop and a surrounding thereof on a front side and Fig. 20 shows an example of an image of an initial overlocking loop and a surrounding thereof on a rear side, respectively. As shown by the drawings, a vicinity of the V point is proximate to a position of folding back the cloth and particularly with respect to the front side, a complicated knitted loop structure is constituted by also adding an influence of a gore line of toe and it is difficult to directly detect the initial overlocking loop from the V point.
However, the initial overlocking loop is brought into a constant positional relationship with other overlocking loop and therefore, a predicted position of the initial overlocking loop can be calculated thereby. Further, although it is difficult to detect an overlocking loop at the V point because of deformation, an overlocking loop disposed at a location remote from the V point to some degree is stabilized and therefore, the overlocking loop can be detected. Hence, the initial overlocking loop is detected by previously detecting an overlocking loop disposed at a position remote from the V point and tracking an overlocking loop line in a reverse direction therefrom.
Although in detecting the initial overlocking loop, a method of detecting the initial overlocking loop slightly differs between the front side and the rear side, in both cases, detection from the V point is difficult and therefore, detection is carried out from an overlocking loop at a midway (this is referred to as a start overlocking loop). Fig. 21 shows a set detecting region of the start overlocking loop. The largest knitted loop is detected in the region. Depending on the stock, areas of an overlocking loop and a knitted loop paired therewith may be the same and it may not be determined whether a detected knitted loop is an overlocking loop or a knitted loop paired therewith. Therefore, it is determined whether a detected knitted loop is an overlocking loop by utilizing the property that an overlocking loop and a knitted loop paired therewith are larger than other knitted loop. That is, as shown by Fig. 22, knitted loops contiguous to a knitted loop detected in the set region in a skewed upper direction and a skewed lower direction therefrom are detected and areas A1 and A2 of the respectives are calculated. A1 and A2 are compared, when A1 is larger, it is determined that the knitted loop disposed in the skewed upper direction therefrom is the overlocking loop and the detected knitted loop is the knitted loop paired therewith and when A2 is larger, it is determined that the knitted loop disposed in the skewed lower direction is the knitted loop paired therewith and the detected knitted loop is the overlocking loop.
Fig. 10 shows an example of a processing flow of a start overlocking loop detecting processing. As shown by the drawing, similar to detection of an ordinary overlocking loop, an image is inputted (S142), a detecting region is set (S144), the image is binarized (S146), and a hole having a predetermined area or more is detected by labeling (S148). Next, a hole having the largest area is sampled (S150), and areas of a hole on the upper left and a hole on the lower left are compared (S152). When the area on the upper left is larger, the hole on the upper left is determined as the overlocking loop (S156). Further, when the hole on the lower left is larger, the hole having the largest area is determined as the overlocking loop (S158).
Next, the final initial overlocking loop is detected by tracking back the overlocking loop line by the fine detecting method from the detected start overlocking loop.
In determining the final initial overlocking loop, the position of the initial overlocking loop is liable to change by the influence of the gore line on the front side. However, a large knitted loop is knitted at a location connecting the overlocking loop line and the gore line and the initial overlocking loop is necessarily present on the upper right of the large knitted loop. Hence, first, an X coordinate of the right end of the large knitted loop is calculated. Since the knitted loop is the largest knitted loop, the detection can be carried out easily. When the overlocking loop line is tracked back by the fine detecting method, the track becomes proximate to the X coordinate finally. Further, the overlocking loop most proximate to the X coordinate is determined as the initial overlocking loop on the front side.
Fig. 11 shows an example of a processing flow of a front side initial overlocking loop detecting processing. First, the camera is moved to a vicinity of a left end (S160), an image is inputted (S162), a detecting region is set (S164), and the image is binarized (S166). A hole having a predetermined area or larger is detected by labeling the binarized image (S168), a hole most proximate to the left end is selected from detected holes (S170) and the detecting reference line is set at a location from a right end of the hole by a predetermined distance (S172). Next, the camera is moved to the start overlocking loop detecting position (S174) and the start overlocking loop is detected (S176). Further, the overlocking loop is tracked back from the start overlocking loop to the detection reference line (S178) and when the gravitational center of the detected overlocking loop exceeds the detection reference line (S180), the finally detected overlocking loop is determined as the initial overlocking loop (S182).
Further, in this case, the detection reference line is set to the right side of the right end of the start overlocking loop by about 1 pitch. Further, the detection reference line may be set to the right end of the start overlocking loop and the overlocking loop at which the gravitational center of the tracked overlocking loop is most proximate to the detection reference line may be determined as the initial overlocking loop.
Figs. 25A, 25B, 25C and 25D show an example of carrying out the front side initial overlocking loop detecting processing by the above-described processing. In this case, the detection reference line is set at the right end of a large knitted loop at a vicinity of the V point as shown by Fig. 25A, the start overlocking loop is detected as shown by Fig. 25B, the overlocking loop is tracked by the finely detecting method as shown by Fig. 25C and the initial overlocking loop is detected as shown by Fig. 25D.
With regard to the rear side, the shape of the initial overlocking loop is not varied considerably and therefore, the overlocking loop line is detected back by the finely analyzing method, the detection reference line is set on the inner side of the V point by a constant distance and the overlocking loop exceeding the detection reference line is determined as the initial overlocking loop. In this case, the detection reference line is set to the inner side of the V point by 1.5 times as large as the basic X pitch.
Fig. 12 shows a processing flow of an initial overlocking loop detecting processing on the rear side. First, the detection reference line is set on the inner side of the left end by a predetermined distance (S130), the camera is moved to the start overlocking loop detecting position (S132), and the start overlocking loop is detected (S134). The overlocking loop is tracked from the start overlocking loop toward the detection reference line (S136), when the gravitational center of the detected overlocking loop exceeds the detection reference line (S138), the finally detected overlocking loop is determined as the initial overlocking loop (140).
Next, a processing of determining whether a detected hole is an overlocking loop will be described. In tracking an overlocking loop in the overlocking loop position detecting processing or the initial overlocking loop detecting processing, before determining a detected hole as an overlocking loop, it is determined whether the overlocking loop is not clearly mistaken in view from a detected location thereof. Here, as shown by Fig. 23, a predetermined range is determined by constituting a reference by an overlocking loop predicted position and when a gravitational center of a knitted loop falls in a range, the knitted loop is determined as the overlocking loop. Further, the predetermined range is set to be ±1/4 X pitch in X direction and ±1/2 Y pitch in Y direction centering on the overlocking loop predicted position.
When the detected overlocking loop does not fall in the range, in the case of the directly detecting method, by switching the directly detecting method to the finely analyzing method and the overlocking loop is detected again and in the case of the finely detecting method, a correct overlocking loop is detected newly by using the above-described start overlocking loop detecting processing.
Further, when assistance of the human being can be carried out, the operation may be switched to manual operation, for example, the human being may be able to designate a correct overlocking loop position by observing a monitor and a next overlocking loop position may be predicted based on the position to continue the automatic processing.
Several embodiments of linking apparatus of the invention will be explained as follows.
Fig. 5 shows an operational flow according to a first embodiment of a linking apparatus of the invention, in which the V point needle is processed manually.
First, the sock W is inserted by the inserting member 110 to expand in the left and right direction (S100), and the V point needle 134 is inserted to the V point (S102). The sock W is expanded in the up and down direction and fixed by the fixing pieces 112a and 112b (S104) and hung by putting the jig to the toe of the sock W (S106).
The jig is put into the toe because as shown by Figs. 26A and 26B, before inserting the jig, the knitting fabric is bulged on the toe side to bring about a difference between tensions on the front side and the rear side, the overlocking loop line on the front side is bent as shown by the left drawing and the overlocking loop lines on the front side and on the rear side are not aligned. Hence, by inserting a toe hanging jig 114 as shown by the upper view into the toe portion of the sock W, the overlocking loop lines are aligned as shown by the right view, the overlocking loop K becomes easy to detect and a time period of positioning the point needle is shortened.
Next, the following point needle piercing processing is carried out for both of the front side and the rear side.
First, an initial overlocking loop detecting processing (S108a, b) is carried out to determine an initial overlocking loop. Next, a camera is moved to a target overlocking loop position (S110a, b), the overlocking loop position is detected (S112a, b), a point needle in correspondence with the detected overlocking loop position is positioned (S114a, b) and the point needle corresponding to the detected overlocking loop is pierced therethrough (S116a, b), which are repeated for all the overlocking loops (S118a, b).
In this case, movement of the camera to the target overlocking loop position (S110a, b) signifies movement of the camera by advancing the needle extruding mechanism 124 to a successive point needle, however, a successive overlocking loop predicted position may previously be calculated and the needle piercing mechanism 120 may simultaneously be moved such that the position is imaged at the center of the field of view of the camera.
Further, with regard to an initial time of the operation, the overlocking loop position detected by the initial overlocking loop detecting processing (S108a, b) can be used and therefore, movement of the camera (S108a, b) and the overlocking loop position detecting processing (S112a. b) can be omitted.
When the processing of piercing the point needle has been finished for all of the overlocking loops, the point needle is returned to an initial position (S120a, b).
Finally, when both of the front side and the rear side are finished, the inserting member 110 is drawn (S122). the sock W is moved to one of the point needles (S124) and overlocked (S126).
Fig. 6 shows an operational flow according to a second embodiment of a linking apparatus of the invention, in which a V point processing is carried out semiautomatically by using a tacking needle.
As shown by Fig. 27, tacking needles 116 are jigs previously pierced through the V points on the both ends of the sock before setting the sock W to the inserting member 110 and by coupling the tacking needles 116 to the V point needles 134 after inserting the inserting member 110 into the sock W, the processing of the V point needles 134 is made to be able to carry out equivalently to other point needle to thereby promote the operational efficiency.
For such purpose, the tacking needle 116 is previously inserted to the V point of the sock W (S200), the sock W is inserted by the inserting member 110 to expand in the left and right direction (S202). the sock W is expanded in the up and down direction to fix (S204), the toe hanging jig 114 is put into the toe to hang (S206) and the V point needle 134 is pierced through the sock W by constituting a guide by the tacking needle 116 (S208).
Thereby, the state of setting the V point needle 134 to the V point of the sock W set to the inserting member 110 can easily be brought about, in the following, overlocking is carried out by processings similar to those of the above-described first embodiment (S228).
Fig. 7 shows an operational flow according to a third embodiment of a linking apparatus of the invention, in which the inserting member 110 both ends of which are converged is used and a processing or piercing all of the point needles including piercing the V point needle into the V point of the sock W is carried out automatically.
As shown by Fig. 28, by inserting the inserting member 110 both end portions of which are converged into the sock W, also the overlocking loops at vicinities of the both ends of the sock W are expanded to be able to detect and therefore, the operation of piercing the point needles including the processing of the V point is fully automated.
First, the sock W is inserted by the inserting member 110 both end portions of which are converged to expand in the left and right direction (S300), the sock W is expanded in the up and down direction to fix (S302), and hung by putting the toe hanging jig 114 into the toe (S304). Although the processing of piercing the point needles thereafter is similar to that of the first embodiment, the initial overlocking loop detecting processing detects the V point. Further, the processing of detecting the V point can be carried out by detecting the start overlocking loop, tracking the overlocking loop toward the end portion therefrom and determining the V point by the overlocking loop most proximate to the end portion similar to the above-described processing of detecting the initial overlocking loop.
Fig. 8 shows an operational flow according to a fourth embodiment of a linking apparatus of the invention, in which a slit is provided at the portion of piercing the point needle by dividing the inserting member 110 in the up and down direction and the point needle can pierce the both faces by a single one of the needle piercing mechanism 120.
The sock W is inserted by the inserting member 110 of an up and down dividing type to expand in the left and right direction (S700) and the V point needle 134 is inserted (S702). Further, the sock W is expanded in the up and down direction to fix (S706), the toe hanging jig 114 is put into the toe to hang (S706) and the inserting member 110 is divided in the up and down direction to thereby form the slit (S708).
Next, the initial overlocking loop detecting processing (S710a, b) is carried out to determined the initial overlocking loop.
The camera is moved to the target overlocking loop position (S712a, b) and the overlocking loop position is detected (S714a, b). The point needle is positioned to the front side overlocking loop position (S716). and the point needle is pierced only through the front side (S718). Further, the point needle is positioned to the rear side overlocking loop position (S720) and the point needle is pierced to the rear side (S722). The above-described processings are repeated from S712a, b until finishing with regard to all of the overlocking loops (S724).
When the point needles have pierced through all of the overlocking loops, the inserting member 110 is drawn (S726) and overlocking is carried out by the point needles (S728).
Thereby, the processing of piercing the point needle through the piercing loops on the both sides can be carried out by the single needle piercing mechanism 120 and further, the processing of butting the needles is dispensed with and the processing time period is shortened.
Although according to all of the above-described embodiments, the CCD camera 140 is mounted to the needle extruding mechanism 124 of the needle piercing mechanism 120 and the center of the field of view is disposed at the position of piercing the point needle 132 extruded by the needle extruding mechanism 124 through the sock W, the invention is not limited thereto but the CCD camera 140 may be mounted to a mechanism of positioning independently from the needle piercing mechanism 120. Further, the CCD camera may fixedly be installed by using a CCD camera having, for example, high resolution, an image of a total of the overlocking loop line of the sock W may simultaneously be picked up and a range of carrying out image processing may successively be moved.
Although according to the above-described embodiments, an explanation has been given such that the toe hanging jig 114 is put into the toe in order to prevent the overlocking loop line on the toe side from being bent, a grubbing mechanism for grubbing the toe may be installed and the toe may be pulled downwardly by grubbing the toe by the grubbing mechanism to achieve a similar effect.
Although according to the above-described embodiments, an explanation has been given such that the inserting member 110 is provided with a width providing a predetermined expanded state when inserting the sock W, a mechanism of expanding the sock W in the left and right direction may be provided and when inserting the sock W, a width easy to insert the sock W may be constituted and after inserting the sock W, the width may be expanded to a width capable of providing the predetermined expanded state.
Although according to the above-described embodiments, an explanation has been given such that in expanding the sock W in the up and down direction, the sock W is expanded manually and fixed by the fixing pierces 112a and 112b, for example, one of the pieces may be constituted by a roller mechanism and after inserting the sock by the inserting member 110, the sock W may be expanded in the up and down direction by driving the roller mechanism.
Next, a processing of positioning a point needle by predicting a moving amount of an overlocking loop position by a point needle which has already been pierced will be shown. As shown by Fig. 13, a detected overlocking loop position is put into a target position and a position of a corresponding point needle is put into a current position (S400), a movement amount is determined by an amount of the target position subtracted by the current position (S402), and an overlocking loop predicted movement amount is predicted from the movement amount (S404).
Here, the overlocking loop predicted movement amount may be calculated by multiplying a constant coefficient by assuming that the overlocking loop predicted movement amount is proportional to the movement amount of the point needle, an approximate equation calculated by experiment may be used, or the overlocking loop predicted movement amount may be calculated by looking up a function table.
Further, the target position is added with the overlocking loop predicted movement amount and the current position is added with the movement amount (S406), the operation is repeated from S402 until a difference between the target position and the current position falls in a range of an allowable error (S408).
Finally, when the difference between the target position and the current position falls in the range of the allowable error, the point needle is positioned to the target position (S410).
Thereby, the positioning can be carried out by one time without actually moving the point needle and therefore, the operational time period is shortened.
Although according to the above-described embodiment, an explanation has been given such that the operation is carried out repeatedly until the difference between the target position and the current position is converged to be equal to or smaller than the allowable error, the invention is not limited thereto but the movement amount of the point needle may be calculated by one time operation by calculating a calculation equation from a recurrent equation, or the movement amount of the point needle may be calculated by one time reference by looking up a function table.
Next, an explanation will be given of a method of preventing a problem that in processing to position a point needle, since a point needle which has already been pierced is moved, a successive overlocking loop is moved and a point needle is positioned by detecting a position of the overlocking loop, repeatedly and therefore, a movement amount of the point needle is accumulated and the point needle is deviated from the inserting member.
As shown by Fig. 14, similar to the processing flow of the processing of piercing an ordinary point needle, the camera is moved to a target overlocking loop position (S500), a processing of detecting a position of an overlocking loop is carried out (S502), a processing of positioning a point needle is carried out (S504), the point needle is pierced (S506) and finally, after returning the point needle to an initial position at every time (S508), a processing of detecting a position of a successive overlocking loop is carried out.
Thereby, when the position of the successive overlocking loop is detected, the point needle is always returned to the original point and therefore, the problem of accumulating the movement amount by moving of the successive overlocking loop by the point needle which has already been pierced is improved.
Next, an explanation will be given of a method of improving a problem that in operation of piercing a point needle, other than a portion of detecting a position of an overlocking loop is always expanded to apply load on the total of knitting fabric.
Fig. 29 shows a conceptual view of a partially expanding mechanism for partially expanding a knitted fabric. As shown by the drawing, rollers 118a and 118b for partially expanding a portion of the knitting fabric an image of which is picked up by the CCD camera 140 are provided and pressed to the sock W inserted by the inserting member 110, the upper roller 118a pulls the sock W upwardly and the lower roller 118b pulls the sock W downwardly. Thereby, only a vicinity of an overlocking loop to be detected can be expanded. The rollers 118a and 118b are mounted to the needle extruding mechanism 124 along with the CCD camera 140 and can selectively expand the knitted fabric at a vicinity of an overlocking loop constituting an object for piercing the selected point needle 132.
Fig. 15 shows a method of carrying out a processing of piercing a point needle by using the partially expanding mechanism. As shown by the drawing, the camera is moved to a target overlocking loop position (S600), the partially expanding mechanism is operated (S602), an overlocking loop position is detected (S604), the point needle is positioned (S606), the point needle is pierced (S608), and the partially expanding mechanism is released (S610). The above-described processings are repeated until all of the overlocking loops have been processed (S612).
Further, it is necessary to position the point needle in operating the partially expanding mechanism and therefore, the point needle is constituted to be locked to a side of the inserting member 110 in operating the partially expanding mechanism and locked to a side of the needle extruding mechanism 124 after releasing the partially expanding mechanism.
Although according to the above-described embodiment, only expansion in the up and down direction is partially carried out, a function of partially carrying out expansion in the left and right direction may be added. For example, rollers may be arranged in skewed four directions to pull the sock W respectively in directions of being remote from the center.
Although according to the above-described embodiment, an explanation has been given by taking the example of a sock as an object of linking, the invention is not limited thereto but is applicable to any knitting fabric so far as overlocking is carried out by butting knitting fabrics having overlocking loops to achieve the effect of the invention.
As described above, according to the invention, the operation of piercing a point needle to an overlocking loop knitted at knitting fabric can automatically be carried out swiftly and accurately to solidly link the knitting fabric.

Claims

A linking method comprising:

a step of expanding a knitting fabric in a state of opposing linking object portions thereof;

a step of picking up an image of the expanded knitting fabric;

a step of detecting a position of an overlocking loop from the picked-up image;

a step of positioning a point needle corresponding to the detected position of the overlocking loop thereto;

a step of piercing the corresponding point needle through the detected overlocking loop; and

a step of overlocking the knitting fabric based on the point needle pierced through each of the overlocking loops of the knitting fabric, further comprising:

a step of setting a detection reference line of an initial overlocking loop at a vicinity of an end portion of the knitting fabric;

a step of detecting a start overlocking loop on an inner side of the end portion of the knitting fabric by a predetermined distance;

a step of tracking the overlocking loop from the detected start overlocking loop toward the set detection reference line; and

a step of determining the initial overlocking loop by a detected overlocking loop when a position of the detected overlocking loop falls to be equal to or smaller than the predetermined distance relative to the set detection reference line by tracking the overlocking loop.
The linking method according to Claim 1, wherein the step of detecting the start overlocking loop comprises:

a step of detecting a hole having an area equal to or larger than a predetermined area by setting a predetermined region on the inner side of the end portion of the knitting fabric by the predetermined distance;

a step of sampling a hole having a maximum area in the detected hole;

a step of comparing areas of a hole on an upper side and a hole on a lower side in holes contiguous to either of left and right sides of the sampled hole having the largest area;

a step of determining an overlocking loop by the hole on the upper side when the area of the hole on the upper side is larger than the area of the hole on the lower side; and

a step of determining the overlocking loop by the detected hole having the largest area when the area of the hole on the lower side is larger than the area of the hole on the upper side.
The linking method according to Claim 1 or Claim 2, wherein the step of setting the detection reference line of the initial overlocking loop comprises:

a step of detecting a hole having an area equal to or larger than a predetermined area by setting a predetermined region at a vicinity of the end portion of the knitting fabric;

a step of selecting a hole most proximate to the end portion of the knitting fabric in the detected hole; and

a step of setting the detecting reference line of the initial overlocking loop from a position of the selected hole.
A linking apparatus comprising:

knitting fabric expanding means for expanding a knitting fabric in a state of opposing linking object portions thereof;

image picking up means for picking up an image of the knitting fabric expanded by the knitting fabric expanding means;

overlocking loop position detecting means for detecting a position of an overlocking loop an image of which is picked up by the image picking up means;

point needle positioning means for positioning a point needle corresponding to the position of the overlocking loop detected by the overlocking loop position detecting means thereto;

point needle piercing means for piercing the corresponding point needle through the detected overlocking loop; and

overlocking means for overlocking the knitting fabric based on the point needle pierced through each of the overlocking loops of the knitting fabric by the point needle piercing means, further comprising:

detection reference line setting means for setting a detection reference line of an initial overlocking loop at a vicinity of an end portion of the knitting fabric;

start overlocking loop detecting means for detecting a start overlocking loop on an inner side of the end portion of the knitting fabric by a predetermined distance;

overlocking loop tracking means for tracking the overlocking loop from the detected start overlocking loop toward the set detection reference line; and

initial overlocking loop detecting means for determining an initial overlocking loop by a detected overlocking loop when a position of the overlocking loop detected by the overlocking loop tracking means falls to be equal to or smaller than the predetermined distance relative to the set detection reference line.
The linking apparatus according to Claim 4, wherein the start overlocking loop detecting means comprises:

detecting means for detecting a hole having an area equal to or larger than a predetermined area by setting a predetermined region on the inner side of the end portion of the knitting fabric by the predetermined distance;

sampling means for sampling a hole having a largest area in the detected hole;

comparing means for comparing areas of a hole on an upper side and a hole on a lower side in a hole contiguous to either of a left side and a right side of the detected hole having the largest area; and

determining means for determining an overlocking loop by the hole on the upper side when the area of the hole on the upper side is larger than the area of the hole on the lower side and determining the overlocking loop by the detected hole having the largest are when the area of the hole on the lower side is larger than the area of the hole on the upper side.
The linking apparatus according to Claim 4 or Claim 5, wherein the detection reference line setting means comprises:

detecting means for detecting the hole having the area equal to or larger than the predetermined area by setting the predetermined region at the end portion of the knitting fabric;

selecting means for selecting a hole most proximate to the end portion of the knitting fabric in the detected hole; and

setting means for setting the detection reference line of the initial overlocking loop from a position of the selected hole.