Patent Description:
For example, a bag making apparatus feeds two or more sheet panels (main components of a bag) each having a web shape, supplies an accessory component(s) such as a side gusset or a bottom gusset to a predetermined position on the sheet panel, and successively makes the bags from the sheet panels and the accessory component.

Whether the accessory component is present in an appropriate state at an appropriate position on the sheet panel can be determined using a change in the thickness of the components. As an example, when the side gusset is appropriately disposed at a predetermined position relative to the sheet panel, the thickness of the sheet panel and the side gusset is detected at the predetermined position. On the other hand, when the side gusset is misaligned relative to the sheet panel, the thickness of the sheet panel is detected at the predetermined position. In this manner, a defect in bag making changes the thickness at a specific position, and the defect can thus be detected using this change.

Such a technique is widely applied to bag making apparatuses. In Patent Document <NUM>, detection of thickness changes is used to detect a foreign object adhering to a bag. In Patent Document <NUM>, detection of thickness changes is used to detect a seam between sheet panels.

In both devices in Patent Documents <NUM> and <NUM>, detection is performed while sheet panels are fed. In these devices, a contactor essential for detection, such as a roller, needs to be kept in contact with the sheet panel at all times, which is likely to damage the sheet panel.

An object of the present application is to provide a defect detecting device for detecting a defect in bag making, the defect detecting device being less likely to damage a component of a bag such as a sheet panel, and a bag making apparatus.

Patent Document <NUM>: <CIT> Patent Document <NUM>: <CIT>.

According to an aspect of the present application, there is provided a defect detecting device for detecting a defect in bag making and for use in a bag making apparatus that intermittently feeds a sheet panel having a web shape in a longitudinal direction of the sheet panel, the defect detecting device including a detection unit, the detection unit including: a support; an arm supported by the support swingably around a swing shaft; and a sensor for detecting a displacement of the arm relative to the support. The arm includes a first contactor and a second contactor that are spaced at a predetermined angular distance from each other around the swing shaft. The defect detecting device further includes a movement mechanism for moving the detection unit between a first position where the first and second contactors are away from a feed plane for the sheet panel and a second position where the first and second contactors reach the feed plane. The movement mechanism is configured to, during a feed phase of the sheet panel, keep the detection unit located at the first position, and to, during a pause phase of the sheet panel, move the detection unit to the second position and then move the detection unit from the second position. The defect detecting device further includes a determination part configured to determine whether the defect is present at least based on data from the sensor obtained when the detection unit is located at the second position.

The determination part may be configured to determine that the defect is not present if a detection value obtained by the sensor when the detection unit is located at the second position is equal to a reference value, and determine that the defect is present if the detection value deviates from the reference value. Alternatively, the determination part may be configured to determine that the defect is not present if the detection value is within a reference range, and determine that the defect is present if the detection value is outside the reference range.

The sensor may be a range sensor disposed to measure a distance between the arm and the support. The determination part in this implementation may be configured to determine that the defect is not present if a distance measured when the detection unit is located at the second position is equal to the reference value, and determine that the defect is present if the measured distance deviates from the reference value. Alternatively, the determination part may be configured to determine that the defect is not present if the measured distance is within the reference range, and determine that the defect is present if the measured distance is outside the reference range.

For example, an angle sensor disposed to measure a swing angle of the arm relative to the support may be used instead of the range sensor. Furthermore, the determination part may be configured to determine the presence or absence of the defect using an angle measured as the detection value and the reference value/the reference range predetermined.

The defect detecting device may further include a warning device configured to output a warning when the determination part determines that the defect is present.

The first and second contactors may be spaced from each other in a width direction of the sheet panel.

Each of the first and second contactors may be a rolling element.

The detection unit may further include a biasing member disposed to bias the first and second contactors toward the sheet panel which is in the feed plane, when the detection unit is located at the second position.

According to another aspect of the present application, there is provided a bag making apparatus for successively making bags from a sheet panel having a web shape and an accessory component, the bag making apparatus including: a feed device configured to intermittently feed the sheet panel in a longitudinal direction of the sheet panel; a supply device configured to supply the accessory component to the sheet panel; and the above-described defect detecting device.

The defect detecting device may be disposed to detect a misalignment of the accessory component relative to the sheet panel.

The supply device may be configured to supply a gusset as the accessory component. The defect detecting device may be disposed to detect a folding failure of the gusset.

The supply device may supply, as the gusset, a side gusset folded in halves to the sheet panel during every intermittent feed cycle of the sheet panel.

Hereinafter, a defect detecting device and a bag making apparatus according to implementations will be described with reference to the drawings.

[Bag Making Apparatus] <FIG> schematically illustrate an example bag making apparatus. The bag making apparatus successively makes bags from sheet panels <NUM> and <NUM>, and an accessory component(s) <NUM> (<FIG>). The sheet panels <NUM> and <NUM> are main components of the bags. In the implementation, the accessory component is a side gusset <NUM>. The sheet panels <NUM> and <NUM>, and the side gussets <NUM> are plastic films. Thus, the bag is a plastic bag. Instead of the plastic film, each of the components <NUM>, <NUM>, and <NUM> may include, for example, a base made of paper and a film or a resin material partly or fully laminated on the base.

The bag making apparatus includes a feed device <NUM> that intermittently feeds at least two sheet panels <NUM> and <NUM> each having a web shape in their longitudinal direction. Thus, the sheet panels <NUM> and <NUM> are repeatedly fed and paused. The reference sign X<NUM> designates a feed direction of the sheet panels <NUM> and <NUM>. The feed device <NUM> includes a pair of feed rollers <NUM> that is driven to intermittently feed, in the direction X<NUM>, the two sheet panels <NUM> and <NUM> sandwiched therebetween.

In the implementation, one wide web is continuously reeled off a roll <NUM>, passes through an accumulation device <NUM>, and is slit in the longitudinal direction into the sheet panels <NUM> and <NUM> by a slitter (not shown), and the sheet panels <NUM> and <NUM> are vertically superposed on each other by a guide device (not shown). Then, the sheet panels <NUM> and <NUM> pass through a dancer device <NUM>. The dancer device <NUM> appropriately converts feed of the sheet panels <NUM> and <NUM> from continuous feed into intermittent feed.

The feed device <NUM> further includes a plurality of guide rollers <NUM> and <NUM> disposed downstream of the dancer device <NUM>. The upper sheet panel <NUM> is separated from the lower sheet panel <NUM> by the guide rollers <NUM>, and the sheet panels <NUM> and <NUM> are again superposed on each other by the guide rollers <NUM>.

The bag making apparatus further includes a supply device <NUM> (<FIG>) that supplies the side gusset <NUM> to the sheet panel <NUM> or <NUM>. The supply device <NUM> in the implementation is a well-known side gusset supply device that supplies a side gusset <NUM> to the lower sheet panel <NUM> during every intermittent feed cycle of the sheet panels <NUM> and <NUM>.

The side gusset <NUM> has been folded in halves on the opposite sides with respect to the longitudinal centerline thereof in advance. The supply device <NUM> places the side gusset <NUM> on the upper surface of the sheet panel <NUM> in the width direction of the sheet panel <NUM> at a position downstream of the guide rollers <NUM> and upstream of the guide rollers <NUM>. The side gusset <NUM> is thus interposed between the sheet panels <NUM> and <NUM> when the sheet panels <NUM> and <NUM> are superposed on each other by the feed device <NUM> (the guide rollers <NUM> thereof).

The bag making apparatus further includes a temporary fix device <NUM> (<FIG>) that temporarily fixes the side gusset <NUM> to the sheet panel <NUM> after the side gusset <NUM> is supplied to the sheet panel <NUM>. The temporary fix device <NUM> adheres the side gusset <NUM> onto the sheet panel <NUM> in the form of, for example, ultrasonic-sealing or heat-sealing to temporarily fix the side gusset <NUM> during every intermittent feed cycle of the sheet panels <NUM> and <NUM>. Specifically, during a pause phase of the sheet panels <NUM> and <NUM>, the supply device <NUM> places the side gusset <NUM> on the sheet panel <NUM>, and thereafter, the temporary fix device <NUM> temporarily fixes the side gusset <NUM> to the sheet panel <NUM>. Such a temporary fix device <NUM> is well-known. A temporary fixing position is the longitudinal centerline of the side gusset <NUM>.

The bag making apparatus further includes a folding device <NUM> that folds a first end of the side gusset <NUM> to form a triangular flap <NUM> (<FIG>). The folding device <NUM> is disposed downstream of the temporary fix device <NUM> and upstream of a position where the sheet panels <NUM> and <NUM> are superposed on each other. The folding device <NUM> folds both corners of the first end of the side gusset <NUM> at an angle of <NUM> degrees to form the triangular flaps <NUM> during every intermittent feed cycle of the sheet panels <NUM> and <NUM>. Such a folding device <NUM> is well-known.

The bag making apparatus further includes a temporary seal device <NUM> that seals the side gusset <NUM> to the sheet panels <NUM> and <NUM> in order to form an open surface <NUM> (<FIG>) as described further below. The temporary seal device <NUM> seals the side gusset <NUM> to the sheet panels <NUM> and <NUM> at at least a second end (the end opposite to the triangular flaps <NUM>) of the side gusset <NUM>. This sealing may be in the form of heat-sealing. Such a temporary seal device <NUM> is well-known.

The bag making apparatus further includes a first forming device <NUM> that forms the open surface <NUM> on the side gusset <NUM>. The first forming device <NUM> may be a well-known guide device including guide members such as a guide roller, a plate, or a pinch roller. As the sheet panels <NUM> and <NUM> are fed, the first forming device <NUM> guides the upper sheet panel <NUM> to fold the sheet panel <NUM> along a fold line <NUM>. The fold line <NUM> extends in the longitudinal direction of the sheet panel <NUM>. When the sheet panel <NUM> is rolled up and folded by the first forming device <NUM>, an upper layer of the side gusset <NUM> is also pulled up together, since the side gusset <NUM> has been sealed at the second end thereof to both the sheet panels <NUM> and <NUM> by the temporary seal device <NUM>. Thereby, the open surface <NUM> having a substantially rhombic shape is formed.

The bag making apparatus further includes a well-known open surface seal device <NUM> that is disposed downstream of the first forming device <NUM> and seals the open surface <NUM> to the sheet panels <NUM> and <NUM> during every intermittent feed cycle of the sheet panels <NUM> and <NUM>.

The bag making apparatus further includes a second forming device <NUM> that forms an auxiliary gusset <NUM> (<FIG>) from the open surface <NUM>. The second forming device <NUM> is disposed downstream of the open surface seal device <NUM>. The second forming device <NUM> may be a well-known guide device including guide members such as a guide roller, a plate, or a pinch roller. As the sheet panels <NUM> and <NUM> are fed, the second forming device <NUM> guides the upper sheet panel <NUM> to fold the sheet panel <NUM> back along the fold line <NUM>. This folding-back causes the open surface <NUM> to be folded in half along the fold line <NUM>, so that the auxiliary gusset <NUM> is formed from the open surface <NUM>.

The bag making apparatus further includes a well-known cross seal device <NUM> that is disposed downstream of the second forming device <NUM> and heat-seals the side gusset <NUM> to the sheet panels <NUM> and <NUM> in the width direction of the sheet panels <NUM> and <NUM> during every intermittent feed cycle of the sheet panels <NUM> and <NUM>. The bag making apparatus further includes a well-known cross cut device <NUM> that is disposed downstream of the cross seal device <NUM> and cross-cuts the sheet panels <NUM> and <NUM> and the side gusset <NUM> in the width direction of the sheet panels <NUM> and <NUM> during every intermittent feed cycle of the sheet panels <NUM> and <NUM>. A bag is made every crosscutting. Although, in addition to the above, the bag making apparatus also includes, for example, a well-known longitudinal seal device that performs sealing parallel to the feed direction of the sheet panels <NUM> and <NUM>, detailed description thereof is omitted.

[Defect Detecting Device] As illustrated as an example in <FIG>, the bag making apparatus further includes a defect detecting device <NUM> for detecting a defect in bag making.

The defect detecting device <NUM> includes a detection unit <NUM> and a movement mechanism <NUM>.

As illustrated in <FIG>, the detection unit <NUM> includes a support <NUM>, a swing shaft <NUM>, an arm <NUM>, and a sensor <NUM>. The arm <NUM> is supported by the support <NUM> via the swing shaft <NUM> to be swingable around the swing shaft <NUM>. The arm <NUM> includes a first contactor <NUM> and a second contactor <NUM> that are spaced at a predetermined angular distance from each other around the swing shaft <NUM>. The sensor <NUM> is configured to detect a displacement of the arm <NUM> relative to the support <NUM>.

As illustrated in <FIG>, the support <NUM> may include two side plates <NUM>, an upper slider <NUM>, and a lower slider <NUM>. The two side plates <NUM> are coupled to each other via the upper and lower sliders <NUM> and <NUM>. The swing shaft <NUM> extends parallel to a feed plane <NUM> for the sheet panels <NUM> and <NUM>.

A lower base <NUM> may be provided. The upper surface of the lower base <NUM> and the feed plane <NUM> are located at the same height. Thus, the lower base <NUM> receives the sheet panel <NUM> or <NUM> being intermittently fed by the feed device <NUM>.

The arm <NUM> may be biased in a counterclockwise direction in <FIG> (the direction in which a detection chip <NUM> approaches a sensor head <NUM>) around the swing shaft <NUM>. The arm <NUM> may be provided for each of the side plates <NUM>. As illustrated in <FIG>, the arm <NUM> includes a first extending portion <NUM>, a second extending portion <NUM>, and a third extending portion <NUM> that extend in three different radial directions of the swing shaft <NUM> from the swing shaft <NUM>. The first and second contactors <NUM> and <NUM> are respectively disposed on the tips of the first and second extending portions <NUM> and <NUM> facing the feed plane <NUM>. Each of the contactors <NUM> and <NUM> in the implementation is a rolling element disposed to be rotatable, and specifically, may be a roller rotatably disposed.

The sensor <NUM> may be a range sensor that measures the distance between the support <NUM> and the arm <NUM> at a predetermined place. The sensor <NUM> is, for example, an eddy current displacement sensor, may include the sensor head <NUM> attached to the support <NUM>/the arm <NUM> and the metallic detection chip <NUM> attached to the arm <NUM>/the support <NUM> to face the sensor head <NUM>, and may measure the distance from the sensor head <NUM> to the detection chip <NUM>. Where a plurality of arms <NUM> are provided, the sensor <NUM> is provided for each of the arms <NUM>.

In the implementation, the sensor head <NUM> is attached to the side plate <NUM>, and the detection chip <NUM> is attached to the tip of the third extending portion <NUM> located opposite to the contactors <NUM> and <NUM>. Thus, when the arm <NUM> swings relative to the support <NUM>, the distance between the sensor head <NUM> and the detection chip <NUM> changes, so that the sensor measures the changed distance. In this manner, the displacement of the arm <NUM> relative to the support <NUM> can be detected. Alternatively, the range sensor may be, for example, an optical sensor.

As illustrated in <FIG>, the movement mechanism <NUM> is configured to move the detection unit <NUM> between a first position (<FIG>) where the first and second contactors <NUM> and <NUM> are away from the feed plane <NUM> and a second position (<FIG>) where the first and second contactors <NUM> and <NUM> reach the feed plane <NUM>. Thus, when the detection unit <NUM> is located at the first position, the contactors <NUM> and <NUM> are not in contact with the components of the bag such as the sheet panels <NUM> and <NUM>, and the side gusset <NUM> which are in the feed plane <NUM>. On the other hand, when the detection unit <NUM> is located at the second position, the contactors <NUM> and <NUM> are in contact with any of the components which is in the feed plane <NUM>, that is, the sheet panel <NUM> or <NUM>, or the side gusset <NUM>.

The movement mechanism <NUM> may include, for example, a support guide <NUM> that supports the detection unit <NUM> movably in the vertical direction and guides the detection unit <NUM>, and an actuator <NUM> (e.g., a cylinder) attached to a frame <NUM> of the bag making apparatus to move the support guide <NUM> together with the detection unit <NUM> in the vertical direction relative to the feed plane <NUM>. The defect detecting device <NUM> may further include a biasing member <NUM> disposed to bias the first and second contactors <NUM> and <NUM> toward the sheet panels <NUM> and <NUM> which are in the feed plane <NUM>, when the detection unit <NUM> is located at the second position.

As illustrated in <FIG>, the support guide <NUM> extends in the vertical direction, and the upper and lower sliders <NUM> and <NUM> are disposed to be slidable along the support guide <NUM>. A stopper <NUM> is disposed on the lower end of the support guide <NUM>. The stopper <NUM> is configured to lock the support <NUM> (the lower slider <NUM> thereof). When the detection unit <NUM> is located at the second position where the contactors <NUM> and <NUM> are in contact with the sheet panel <NUM> or <NUM>, the side gusset <NUM>, or the lower base <NUM>, the lock between the lower slider <NUM> and the stopper <NUM> is released, so that a distance d1 is created between the lower slider <NUM> and the stopper <NUM>.

The biasing member <NUM> may be, for example, a coil spring. The support guide <NUM> having a columnar shape is inserted through the biasing member <NUM>. The biasing member <NUM> is disposed and extends between an adjustment nut <NUM> and the detection unit <NUM>, thereby biasing the detection unit <NUM> downward. The adjustment nut <NUM> is disposed on and around a threaded outer peripheral surface of the support guide <NUM> to be screwed therewith. A biasing force of the biasing member <NUM> can be adjusted by operating the adjustment nut <NUM> to move the adjustment nut <NUM> relative to the support guide <NUM> along the support guide <NUM>.

According to this configuration, when the movement mechanism <NUM> moves the detection unit <NUM> from the first position to the second position to create distance d1, the biasing member <NUM> is compressed by the distance d1 to generate the predetermined biasing force. Thereby, the contactors <NUM> and <NUM> are biased toward the sheet panels <NUM> and <NUM> which are in the feed plane <NUM>. This ensures that the contactors <NUM> and <NUM> are brought into intimate contact with the component <NUM>, <NUM>, or <NUM> of the bag.

When the movement mechanism <NUM> lifts the support guide <NUM> in a state illustrated in <FIG> using the actuator <NUM> by the distance d1, the stopper <NUM> is locked to the lower slider <NUM>. Thus, when the movement mechanism <NUM> further lifts the support guide <NUM>, the detection unit <NUM> moves upward together with the support guide <NUM>, so that the contactors <NUM> and <NUM> are away from the feed plane <NUM>. Thus, the biasing force is not applied to the component <NUM>, <NUM>, or <NUM>.

The movement mechanism <NUM> keeps the detection unit <NUM> located at the first position during a feed phase of the sheet panels <NUM> and <NUM>. Furthermore, during a pause of the sheet panels <NUM> and <NUM>, the movement mechanism <NUM> moves the detection unit <NUM> from the first position to the second position and then moves the detection unit <NUM> from the second position to the first position.

As illustrated only in <FIG>, the defect detecting device <NUM> further includes a determination part <NUM> and a warning device <NUM>. The determination part <NUM> is configured to determine whether a defect in bag making is present as described further below at least based on data from the sensor <NUM> obtained when the detection unit <NUM> is located at the second position. Hereinafter, an operation of defect detection will be described with reference to <FIG>.

As illustrated in <FIG>, the movement mechanism <NUM> moves the detection unit <NUM> from the first position to the second position to bring the contactors <NUM> and <NUM> into contact with the sheet panel <NUM>, or <NUM> or the side gusset <NUM> during a pause of the sheet panels <NUM> and <NUM>. <FIG> illustrates a state in which the contactors <NUM> and <NUM> are in contact with the component <NUM>, <NUM>, or <NUM> of the bag when no defect is present (illustration of the component is omitted). Reference signs C1 and C2 designate contact points of the contactors <NUM> and <NUM> with the component <NUM>, <NUM>, or <NUM>, respectively. Reference sign Hr designates a relative height between the contactors <NUM> and <NUM> when no defect is present. Although Hr is not zero in the example of <FIG>, Hr may become zero when no defect is present.

An output from the sensor <NUM> when no defect is present, that is, the distance Lr in the implementation is stored in a storage medium as a reference value in the detection unit <NUM>. When no defect is present, the sensor <NUM> of the detection unit <NUM> located at the second position measures the same distance as the reference value Lr.

When a defect is present, the defect changes the thickness at this position. Thus, when the contactor <NUM> or <NUM> comes into contact with this defective point, the relative height between the contactors <NUM> and <NUM> differs from Hr, which causes a displacement (swing) of the arm <NUM> relative to the support <NUM>. Thus, when a defect is present, the sensor <NUM> of the detection unit <NUM> located at the second position measures a distance different from the reference value Lr. The reference value Lr can vary depending on a defect to be detected.

Thus, the determination part <NUM> can detect the presence or absence of a defect based on the reference value Lr previously determined depending on a defect to be detected and a detection value obtained by the sensor <NUM> when the detection unit <NUM> is located at the second position (that is, when the contactors <NUM> and <NUM> are in contact with the sheet panel <NUM> or <NUM>, or the side gusset <NUM>).

Specifically, the determination part <NUM> compares a distance measured when the detection unit <NUM> is located at the second position with the reference value Lr. When the measured distance is equal to the reference value Lr, the determination part <NUM> determines that no defect is present. On the other hand, when the measured distance deviates from the reference value Lr, the determination part <NUM> determines that a defect is present.

Thereafter, the movement mechanism <NUM> moves the detection unit <NUM> from the second position to the first position to separate the contactors <NUM> and <NUM> from the sheet panel <NUM> or <NUM>, or the side gusset <NUM>. Then, the feed device <NUM> restarts to feed the sheet panels <NUM> and <NUM>. Such an operation of defect detection is repeated during every intermittent feed cycle.

The determination part <NUM> may be implemented, for example, by a processor executing a program stored in a storage medium.

The warning device <NUM> is configured to output a warning when the determination part <NUM> determines that a defect is present. The warning device <NUM> may include a visual device such as an LED, a lamp, or a display, and/or an auditory device such as a speaker. Thus, the output of a warning may be executed by means of light emission and/or sound generation. The warning device <NUM> may be configured to display a defective point on a display.

[Example of Defect Detection] Hereinafter, examples of defect detection in bag making will be described. As illustrated in <FIG>, in the bag making apparatus, a plurality of detection units 6a to 6e are provided. The movement mechanism <NUM>, the biasing member <NUM>, and the adjustment nut <NUM> (e.g., <FIG>) are provided for each of the detection units 6a to 6e.

The detection units 6a to 6d are placed upstream of the first forming device <NUM> so as to face the side gusset <NUM> during a pause phase of the sheet panels <NUM> and <NUM>. The defect detecting device <NUM> simultaneously determines the presence or absence of a defect at a plurality of points using the detection units 6a to 6d. <FIG> illustrates example settings of the respective contact points Cal, Ca2, Cb1, Cb2, Cc1, Cc2, Cdl, and Cd2 of the contactors <NUM> and <NUM> of the detection units 6a to 6d.

The detection unit 6a is used to detect, as a defect, the presence or absence of a curling-up portion of the side gusset <NUM> (an example of a folding failure). As illustrated in <FIG>, when no curling-up portion is present, the contact points Ca1 and Ca2 are at the same height. On the other hand, as illustrated in <FIG>, when a curling-up portion is present, the contact points Ca1 and Ca2 are at different heights. Thus, when a curling-up portion is present, a distance measured by the sensor <NUM> deviates from the reference value Lr. Thus, the determination part <NUM> can determine whether a curling-up portion is present based on data from the sensor <NUM>.

As illustrated in <FIG>, the presence or absence of a curling-up portion may be detected at two different points. In this case, two detection units 6a are provided, or one detection unit 6a includes two arms <NUM>. The contact points Ca1 and Ca2 are paired, and contact points Ca1' and Ca2' are paired. As is obvious from <FIG>, the height of the contact point Ca2/Ca2' differs between when a curling-up portion (defect) is present and when no curling-up portion (defect) is present. Thus, the determination part <NUM> can detect the presence or absence of a curling-up portion at multiple points. Where multiple detection points are set in this manner, the warning device <NUM> may output a warning when a defect is present at any one of the detection points.

As illustrated in <FIG>, it is also possible to detect the presence or absence of a curling-up portion that may occur at the corners on both sides of the side gusset <NUM>. When no curling-up portion is present as illustrated in <FIG>, the contact points Ca1 and Ca2 are at different heights. On the other hand, when a curling-up portion is present as illustrated in <FIG>, the contact points Ca1 and Ca2 are at the same height. The same applies to the contact points Ca1' and Ca2'.

Each of the detection units 6b and 6c is used to detect, as a defect, the presence or absence of formation of the triangular flap <NUM> of the side gusset <NUM> (an example of the folding failure). That is, when the triangular flap <NUM> is appropriately formed as illustrated in <FIG> (when no defect is present), the contact points Cb1 and Cb2 are at different heights. On the other hand, when the triangular flap <NUM> is not formed, the contact points Cb1 and Cb2 are at the same height (not shown). The same applies to the contact points Cc1 and Cc2. Thus, the determination part <NUM> can determine the presence or absence of formation of the triangular flap <NUM> based on data from the sensor <NUM>.

The presence or absence of formation of both the triangular flaps <NUM> may be detected using one detection unit <NUM> including two arms <NUM>.

The detection unit 6d is used to detect, as a defect, a misalignment of the side gusset <NUM> toward a first side edge <NUM> (<FIG>) of the sheet panels relative to the sheet panels <NUM> and <NUM>. <FIG> illustrates arrangement of the side gusset <NUM> wherein the edge <NUM> where the open surface <NUM> (<FIG>) is formed is displaced toward the first side edge <NUM> relative to an allowable limit line <NUM> (see arrow S). Reference numeral <NUM> designates a second side edge of the sheet panels, and reference numeral <NUM> designates a temporary sealed section formed by the temporary seal device <NUM> (<FIG>). The temporary sealed section <NUM> includes a rectangular sealed section <NUM> and a triangular sealed section <NUM> located on one end of the section <NUM>, and is drawn on a larger scale than actual in <FIG> for the sake of convenience. The allowable limit line <NUM> is a virtual line extending through the tip of the temporary sealed section <NUM> (the triangular sealed section <NUM>) in the longitudinal direction of the sheet panels <NUM> and <NUM>.

As illustrated in <FIG>, when the edge <NUM> is displaced toward the first side edge <NUM> relative to the allowable limit line <NUM>, the sheet panels <NUM> and <NUM> are sealed to each other in the tip area of the triangular sealed section <NUM>. Thus, the first forming device <NUM> fails to perform processing for forming the open surface <NUM> (<FIG>).

As illustrated in <FIG>, the contact points Cd1 and Cd2 of the detection unit 6d are set at positions close to the first side edge <NUM>. As illustrated in <FIG>, when the side gusset <NUM> is placed in such a manner that the edge <NUM> is located closer to the second side edge <NUM> than the allowable limit line <NUM> is or located on the allowable limit line <NUM> (when no defect is present), the contact points Cd1 and Cd2 are at the same height. On the other hand, as illustrated in <FIG>, when the side gusset <NUM> is placed in such a manner that the edge <NUM> is located closer to the first side edge <NUM> than the allowable limit line <NUM> is (when a defect is present), the contact points Cd1 and Cd2 are at different heights (because the height of the contact point Cd1 when a defect is present is higher than that when no defect is present). Thus, the determination part <NUM> can determine the presence or absence of a misalignment of the side gusset <NUM> relative to the sheet panels <NUM> and <NUM> based on data from the sensor <NUM>.

As illustrated in <FIG>, the detection unit 6a may be used instead of the detection unit 6d. One contact point Ca1 is set closer to the first side edge <NUM> (<FIG>) than the allowable limit line <NUM> is. The other contact point Ca2 is set on the allowable limit line <NUM>. As illustrated in <FIG>, when the side gusset <NUM> is placed in such a manner that the edge <NUM> is located closer to the second side edge <NUM> than the allowable limit line <NUM> is or located on the allowable limit line <NUM> (when no defect is present), the contact points Ca1 and Ca2 are at the same height. On the other hand, as illustrated in <FIG>, when the side gusset <NUM> is placed in such a manner that the edge <NUM> is located closer to the first side edge <NUM> than the allowable limit line <NUM> is (when a defect is present), the contact points Ca1 and Ca2 are at different heights (because the height of the contact point Ca2 when a defect is present is lower than that when no defect is present).

The detection unit 6e in <FIG> is disposed downstream of the second forming device <NUM> and used to determine the presence or absence of a formation failure of the auxiliary gusset <NUM> (an example of the folding failure). <FIG> illustrates settings of the contact points Ce1 and Ce2 of the detection unit 6e. As illustrated in <FIG>, when the auxiliary gusset <NUM> is appropriately formed (when no defect is present), the contact points Ce1 and Ce2 are at the same height. On the other hand, when the auxiliary gusset <NUM> is not appropriately formed (when a defect is present), the contact points Ce1 and Ce2 are not at the same height. Thus, the determination part <NUM> can determine a formation failure of the auxiliary gusset <NUM> based on data from the sensor <NUM>.

As described above, the defect detecting device <NUM> can detect various defects in bag making using the detection unit <NUM>. As described in the implementation, since the movement mechanism <NUM> brings the contactors <NUM> and <NUM> into contact with the component <NUM>, <NUM>, or <NUM> of the bag only when the sheet panels <NUM> and <NUM> are being paused, the component <NUM>, <NUM>, or <NUM> is less likely to be damaged.

Also, since the contactors <NUM> and <NUM> are not in constant contact with a measurement surface, measurement can be performed without any problems not only on continuous measurement surfaces, but also on discontinuous measurement surfaces with a step. For example, in a zone where the sheet panels <NUM> and <NUM> are separated from each other in <FIG>, a step generated by an edge (boundary) of the side gusset <NUM> placed on the sheet panel <NUM> may be measured.

Since the contactors <NUM> and <NUM> are brought into contact with the component <NUM>, <NUM>, or <NUM> not during a feed phase, but during a pause phase of the sheet panels <NUM> and <NUM>, intimate contact of the contactors <NUM> and <NUM> with the component <NUM>, <NUM>, or <NUM> of the bag is ensured even if the biasing force of the biasing member <NUM> is weak. This contributes to reducing the weight or cost of the detection unit <NUM>.

The bag making apparatus is merely an example. The accessory component may be a gusset other than the side gusset, such as a bottom gusset or a top gusset. The accessory component may be a top face portion or a bottom face portion that does not function as a gusset. The accessory component may be a zipper for opening and closing a bag. Thus, in addition to or instead of the side gusset supply device, a supply device that supplies another accessory component may be provided. Also, the bag making apparatus may provide multiple-line bag making.

The detection unit <NUM> can be oriented such that the contactors <NUM> and <NUM> can be spaced from each other in both the longitudinal direction and the width direction of the sheet panels <NUM> and <NUM>. The detection unit <NUM> have a high degree of flexibility in its orientation and can be used to detect various defects in bag making.

As illustrated in <FIG>, the first and second contactors <NUM> and <NUM> may be balls that are smaller than the rollers and rollably provided on the tips of the first and second extending portions <NUM> and <NUM>, respectively. Defect detection can be performed in a narrow area by using such a ball. Although it is preferable that the first and second contactors <NUM> and <NUM> are rolling elements such as rollers or balls in view of preventing the component <NUM>, <NUM>, or <NUM> of the bag from being damaged, the first and second contactors <NUM> and <NUM> may be composed of the tips of the first and second extending portions <NUM> and <NUM>.

The contact points C1 and C2 may be adjusted by adjusting a dimension d2 in <FIG>.

The detection unit <NUM> may be configured such that the distance between the sensor head <NUM> and the detection chip <NUM> increases when a defect is present. This prevents collision of the sensor head <NUM> with the detection chip <NUM>.

The support guide <NUM> of the movement mechanism <NUM> may be omitted. The support <NUM> may be directly coupled to the actuator <NUM> and moved by the actuator <NUM>. Also, the arm <NUM> may be vertically movable and swingable relative to the support <NUM> with the biasing force applied thereto toward the sheet panels <NUM> and <NUM> which are in the feed plane <NUM>.

As the sensor <NUM>, an angle sensor disposed to measure a swing angle of the arm <NUM> relative to the support <NUM> may be used instead of the range sensor. The angle sensor is, for example, a rotary encoder. In this case, the reference value used for defect detection is not a distance, but an angle.

The determination part <NUM> determines the presence or absence of a defect based on the detection value (e.g., a measured distance or angle obtained when the detection unit <NUM> is located at the second position) and the reference value. Taking an allowable error or the like into consideration, the determination part <NUM> may determine the presence or absence of a defect based on the detection value and a predetermined reference range. The reference range is a certain range including the reference value. The determination part <NUM> determines that no defect is present when the detection value is within the reference range and determines that a defect is present when the detection value is outside the reference range.

The reference value may be calculated in advance by a user or a processor of the bag making apparatus based on a defect to be detected, the thickness of the component <NUM>, <NUM>, or <NUM>, the configuration of the detection unit <NUM>, etc. Alternatively, the reference value may be acquired by actual measurement in advance in a preparatory stage before operation (bag making process). In the preparatory stage, the contactors <NUM> and <NUM> are brought into contact with the component <NUM>, <NUM>, or <NUM> with no defect at a point where detection is to be performed. Then, a detection value (e.g., the measured distance or angle) obtained by the sensor <NUM> at this contact is stored, as the reference value (normal value), in a storage medium of the defect detecting device <NUM> or the bag making apparatus. During operation of the bag making apparatus, the defect detecting device <NUM> detects a defect as described above using the reference value obtained in this manner or a reference range determined based on the reference value.

The timing of bringing the contactors <NUM> and <NUM> into contact with the component <NUM>, <NUM>, or <NUM> for defect detection may be determined in advance according to the type of a bag to be made. For example, in one implementation, the actuator <NUM> and the support guide <NUM> are disposed on a structural member that moves in conjunction with a sealing operation by the bag making apparatus. In this implementation, only when the structural member is moving during operation of the bag making apparatus, the contactors <NUM> and <NUM> can be brought into contact with the component <NUM>, <NUM>, or, <NUM> to detect a defect. During non-operation of the bag making apparatus, the structural member is located at a top dead center. As a result, the actuator <NUM> and the support guide <NUM> are too far apart from the feed plane <NUM>, and the contactors <NUM> and <NUM> fail to be brought into contact with the component <NUM>, <NUM>, or, <NUM>. Thus, in this implementation, the reference value fails to be measured in the preparatory stage before operation.

Thus, a modification in this implementation provides an example defect detecting device <NUM> configured to be capable of measuring the reference value in advance by lifting the lower base <NUM> to bring the contactors <NUM> and <NUM> into contact with the component <NUM>, <NUM>, or <NUM> before operation (bag making process).

As illustrated in <FIG>, <FIG>, the defect detecting device <NUM> further includes a lifting mechanism <NUM> for lifting and lowering the lower base <NUM>. The lifting mechanism <NUM> includes: a rotation shaft <NUM> located under the lower base <NUM>, extending in the width direction of the sheet panels <NUM> and <NUM> and supported by a frame (not shown) to be rotatable around its axis; at least one lift arm <NUM> attached to the rotation shaft <NUM> to rotate together with the rotation shaft <NUM>; and at least one lever <NUM> for operation coupled to the rotation shaft <NUM>. In the example, two lift arms <NUM> are spaced from each other in the axial direction of the rotation shaft <NUM>, and one of the levers <NUM> is provided on one end of the rotation shaft <NUM>.

As illustrated in <FIG>, the lifting mechanism <NUM> further includes a slider <NUM> that has a post shape and extends downward from the lower surface of the lower base <NUM>, and guide rollers <NUM> disposed to sandwich the slider <NUM> therebetween so as to guide the slider <NUM> in the vertical direction. Each of the lift arms <NUM> includes a lift roller <NUM> on its tip. The lift roller <NUM> is in contact with the lower surface of the lower base <NUM> and supports the lower base <NUM>. Thus, the lift roller <NUM> preferably has high wear resistance and has a smooth surface.

According to the configuration described above, the operation of the lever <NUM> causes the lift arms <NUM> to rotate in unison around the rotation shaft <NUM> together with the rotation shaft <NUM>. This enables the lower base <NUM> to be lifted and lowered by the guide rollers <NUM> and the lift rollers <NUM> with its upper surface maintained horizontal. A lifting mechanism having another configuration may be used for lifting and lowering the lower base <NUM>.

Claim 1:
A defect detecting device (<NUM>) for detecting a defect in bag making and for use in a bag making apparatus that intermittently feeds a sheet panel (<NUM>, <NUM>) having a web shape in a longitudinal direction of the sheet panel (<NUM>, <NUM>),
the defect detecting device (<NUM>) characterized by comprising a detection unit (<NUM>),
the detection unit (<NUM>) comprising a support (<NUM>)
characterized in that it further comprises:
an arm (<NUM>) supported by the support swingably around a swing shaft (<NUM>); and
a sensor (<NUM>) for detecting a displacement of the arm (<NUM>) relative to the support (<NUM>),
the arm (<NUM>) comprising a first contactor (<NUM>) and a second contactor (<NUM>) that are spaced at a predetermined angular distance from each other around the swing shaft (<NUM>),
the defect detecting device (<NUM>) further comprising a movement mechanism (<NUM>) for moving the detection unit (<NUM>) between a first position where the first and second contactors are away from a feed plane for the sheet panel (<NUM>, <NUM>) and a second position where the first and second contactors (<NUM>, <NUM>) reach the feed plane (<NUM>), the movement mechanism (<NUM>) being configured to, during a feed phase of the sheet panel (<NUM>, <NUM>), keep the detection unit (<NUM>) located at the first position, and to, during a pause phase of the sheet panel (<NUM>, <NUM>), move the detection unit (<NUM>) to the second position and then move the detection unit from the second position,
the defect detecting device (<NUM>) further comprising a determination part (<NUM>) configured to determine whether the defect is present at least based on data from the sensor (<NUM>) obtained when the detection unit (<NUM>) is located at the second position.