Gas-Filliing Packaging Method and Packaging Machine Therefor

A gas-filling packaging method using a track type gas-filling packaging machine includes a bag placing step in which a number of packaging bags set in a magazine in a stacked state are turned up one by one by a sucker and picking up and then passing the bag to a bag chuck, a bag opening/inflating step of opening the bag mouth and inflating the bottom of the bag by suckers, a bag filling step of lowering a synchronous funnel to be inserted into the bag and applying a receiving member of a bottom tapping unit to the bag, so that the bag is filled with a predetermined amount of article while the bottom is tapped, a deaeration/temporarily sealing step of inserting a deaeration nozzle into the bag to remove air in the bag and holding the bag mouth by a temporary heater.

DETAILED DESCRIPTION

An embodiment of the invention will be described with reference to the accompanying drawings.

Referring toFIGS. 1 and 2, a track type gas-filling packaging machine P is shown to which the gas-filling packaging method and machine each according to the present invention are applied. The packaging machine P continuously executes shaping during steps from filling a large-sized bag with an article such as about 10 to 20-kilogram rice, pet food or fertilizer and sealing the bag to temporarily sealing a bag mouth, whereby packaging can be executed which achieves stable products that are unlikely to cause collapse when the products are laid out flat. Furthermore, the packaging machine P can automatically execute all works including switch of related apparatus with change in a bag size based on operator's instructions. The packaging process includes a bag feeding step (1), an unzipping step (2) in which a zippered bag is unzipped when the zippered bag is used, a one-point sealing step (3), a bag opening/inflating step (4), a filling step (5), a vibrating/gas filling step (6) and (7), a deaeration/temporarily sealing step (8), a first sealing step (9), a second sealing step (10) and a cooling/discharging step (11), as shown inFIGS. 1 and 4.

The packaging machine P is constructed so that a number of grip units5are each horizontally moved along an annular passage3including two linear sections3aand3band two semicircular sections3cand3dlocated at opposite ends of the linear sections3aand3brespectively, as shown inFIGS. 1 to 3. The packaging machine P is also constructed so that the grip units5are intermittently moved for every one of the above-mentioned steps and so that a packaging bag supported by grips11of each grip unit5in a suspended manner with a bag mouth up is filled with an article and then with an inert gas (nitrogen gas) for maintenance of quality. The packaging machine P is further constructed so that the bag mouth is heat-sealed. All the steps from the bag placing step to the seal cooling/bag removing step are arranged at one3aof the linear sections constituting the annular passage3. Main apparatus and units composing the packaging machine P and essential points of the main apparatus and the units will be described as follows.

Although the packaging machine P divides a bag mouth sealing step into a first sealing step (9) and a second sealing step (10) to maintain the certainty of heat sealing, a single step may be employed, instead of the two steps.

A packaging bag includes a gusset bag having two side edges including respective folded portions, a standing pouch having a bottom including a folded portion, a zippered gusset bag and a zippered standing pouch. Regarding a size of the bag in the embodiment, the width ranges from 300 to 400 mm and the length (height) ranges from 600 to 1050 mm. The folded portion has the length ranging from 100 to 200 mm when expanded.

Each grip unit5includes a base6, a plurality of sets of rollers7rotatably mounted on the base6as shown inFIGS. 5 and 6. The rollers7are attached to the rails4aand4bforming the annular passage3. The base6is mounted to an annular conveyor belt4driven by a known intermittent drive unit (not shown) including a Geneva drive and a servomotor both incorporated in a machine base1, so as to be intermittently moved.

A pair of right and left holders8are rotatably mounted on the base6as shown inFIG. 6. The holders8are coupled with each other by a link9. The holders8are provided with grips11having holding portions12respectively. A link mechanism13includes an actuating lever13afurther including a roller14. A servomotor drive unit (not shown) is provided for driving the roller14so that a pressing member (not shown) is controlled so as to be movable forward and rearward, whereby the holding portions12are openable and closable.

Regarding a distance (w) between the holding portions12of one set of grips11, a roller15mounted on a lever8aextending from one of the holders8is driven so that a pressing member17is controlled so as to be movable forward and rearward, whereby the distance between the holding portions12is automatically adjustable according to the bag width. Reference numeral18designates a coil spring suspended between the holders8. The roller15is pressed against the pressing member17so that the distance (w) between the holding portions12is maintained at a constant value.

Bag Feeder

A bag feeder (a bag feeding unit)20includes a bag replenishing unit22which drops into a guide of a bag positioning unit35a packaging bag stacked on a magazine31and the bag positioning unit35which positions a guide according to a bag size entered on an operation panel2provided on the packaging machine P. A packaging bag is sent in a predetermined posture to a grip11standing by at a bag feeding step (1) by cooperation of the bag supply unit45and a cramp unit50.FIG. 7shows main work contents of the bag feeder20.

Referring toFIG. 8, a sucker24is movable upward and downward by a servomotor drive unit (a drive mechanism)23mounted on a frame21. The bag replenishing unit22is constructed so that a number of packaging bags set in the magazine in a stacked state are turned up one by one from a top by the sucker24thereby to be picked up to a predetermined level. Reference numeral27designates a bag chuck which is horizontally movable and is openable and closable by actuation of a cylinder26. The bag chuck27is constructed to grip one of side edges (a side edge near the bag positioning unit) of the bag picked up by the sucker24of the bag replenishing unit22and to drop the bag into a guide of the adjacent bag positioning unit35.

The magazine31includes chains30which are disposed on a frame in parallel to each other in a horizontal direction and are driven by different drive units so as to be capable of normal rotation and reverse rotation. Two side guides32aand32bare attached to the chains30respectively. Rotational directions of the chains30are changed so that a distance between the side guides32aand32bis automatically adjusted to a predetermined bag width. A plurality of magazines31is configured to be circularly movable from a supply position (L1) where a bag is filled while a predetermined bag width is maintained or a standby position (L2) to a replenishing position (L3) where the side edge of the bag is gripped by the bag chuck27, when both chains30are driven in the same direction.

Positions of the side guides36and37corresponding to the bag width are automatically adjusted by a servomotor drive unit (not shown) based on entered data, and a position of a rear end guide38is automatically adjusted by a servomotor drive unit39, whereby the bag positioning unit35positions the bag. Furthermore, a front end guide40at the bag mouth side is provided to automatically switch a position thereof by an actuator41so as to correspond to a normal plastic bag or a paper bag. A guide in the embodiment refers to the construction comprised of the side guides36and37and the front end guide40.

When the packaging bag is a paper bag, the paper bag is formed into a shape such that a front and a back thereof include respective bag mouth portions having different heights, and the paper bag has an inner surface coated with a resin. The packaging machine P applies a temporary seal to the bag mouth and thereafter, a part of the bag located above the seal is folded and sewn by a sewing unit installed outside the system. Accordingly, since the heights of the bags are not equal and the lower side is the basis in the case of the paper bag, the length (h) from a position where the bag is held by the grips11to the bag mouth is adjustable by the front end guide40so as to be capable of being rendered larger than the normal plastic bag, as shown inFIG. 10.

An arm47is fixed to a shaft46controlled by a cam (not shown). The bag supply unit45is constructed to reciprocally rotate the arm47between a grip position of the bag and a position where the bag is passed to the cramp56of the cramp unit50. Reference numeral48designates a chuck mounted on a distal end of the arm47.

A main shaft1a(seeFIG. 3) controls timing of an entire apparatus or mechanism by a drive mechanism incorporated in the machine base1of the packaging machine P. The main shaft1ais provided with a plurality of cams (not shown). A lever52is fixed to a shaft51the rotation of which is controlled by a specific one of the cams. The cramp unit50includes a base55which is provided with a pair of cramps56and is movable in a front-back direction by the lever52as shown inFIG. 9. The cramps56are constructed to be openable and closable by a lever54fixed to a shaft53the rotation of which is controlled by a cam (not shown). The base55is movable upward and downward by a servomotor drive unit57based on data detected by a laser sensor49provided on the arm47. As a result, the height of the bag held by the cramps56is automatically adjustable to a predetermined dimension. This function is referred to as “bag height compensating function.” The bag height compensating function is constructed according as a known mechanism disclosed by Japanese patent application publication No. JP-A-2011-6129 that is an example of a packaging bag feeder by the applicant.

A number of packaging bags set in the magazine in a stacked state are turned up one by one from a top by the sucker24of the bag replenishing unit22thereby to be picked up to the bag chuck27. The bag gripped by the bag chuck27is transferred to the adjacent bag positioning unit35to be dropped into the guide of the unit35. The side guides36and37and front and rear end guides40and38are positioned by automatically adjusting the positions of the side guides36and37corresponding to the bag width of the guide and the positions of the front and rear end guides40and38based on the entered data. Next, the bag (a) in the guide is gripped by the chuck48of the bag supply unit45and is held by the cramp56of a cramp unit50standing by above to be sent to the grips11standing by at the bag feeding step (1), whereby the bag feeder20is constructed.

A one-point sealing unit60is provided in a point seal step (3). V-shaped folded portions (c) are formed on both side edges of the gusset bag as shown inFIG. 10. The large-sized bag (a) used with the packaging machine P has a folded portion with a length of 50 mm or 100 mm in a folded state thereof. The lower mouth of the synchronous funnel is inserted into the bag (a) while the bag (a) is open. In this case, if the folded portion (c) protrudes into the inner center of the bag, there is a possibility that the lower mouth may interfere with the folded portion (c). In view of the possibility of interference, the one-point sealing unit60is configured to apply heat seal to overlapping portions of the front or the back of the bag and one of V-shaped folded portions of both side edges of the bag, whereby the overlapping portions are fixed together.

A bag opening/inflating step (4) is provided with an opening unit62which opens the bag by an adsorption action of the suckers63which are mounted at both sides of the bag (b) so as to be movable forward and backward respectively and a preshaping unit65. The preshaping unit65is configured to render the bottom of the bag inflated by an adsorption action of the suckers66provided at both lower sides so as to be movable forward and backward respectively.

Filler

A filler (a filling unit)70is configured to fill the bag with a predetermined amount of the article by the synchronous funnel77which is controlled to be moved upward and downward and horizontally in synchronization with transfer of the bag. In more detail, an annular conveyor belt72extending between a pair of pulleys71disposed at a predetermined distance therebetween as viewed in a plane view is provided with a lifting unit73. The lifting unit73includes a slide76on which is mounted the synchronous funnel77provided with a filling nozzle78. The lifting unit73includes a lower end73bmovably attached to a rail75forming a second annular passage70a.The lifting unit73is controlled by a servomotor drive unit74so as to be moved upward and downward in synchronization with transfer of the bags. Furthermore, the lifting unit73is also controlled by a servomotor drive unit (not shown) so as to be moved horizontally.

Bottom tapping units80are disposed at a bag filling step (9), a vibrating/gas filling step (6) and (7) and an aeration/temporary seal step (8) respectively (FIGS. 11 and 12). The bottom tapping units80are configured to move a receiving member83by converting a rotational movement by the servomotor drive unit81installed at the machine base1side to a linear movement by a crank mechanism82. Reference numeral85designates a servomotor drive unit moves the bottom tapping unit80attached to a vertically disposed guide member84thereby to adjust the height.

In the filling step (5), the synchronous funnel77is lowered by driving the servomotor drive unit74to be inserted into the bag, and the receiving member83of the bottom tapping unit80is applied to the bottom of the bag and the bag is tapped so that the article is prompted to drop, and the bag is filled via the synchronous funnel77with a predetermined amount of article discharged from a weighing apparatus (not shown).

A filling unit70is constructed to insert the synchronous funnel77into the bag by lowering the synchronous funnel77by the drive of the servomotor drive unit74and to fill the bag with a predetermined amount of an article discharged from a weighing apparatus (not shown) in the filling step (5) while helping the article drop by applying the receiving member83of the bottom tapping unit80to tap the bag and to start to supply an inert gas into the bag by a gas nozzle at a last moment of the filling operation.

Shaping Apparatus

A shaping apparatus (a shaping unit) is configured to shape the bag into a desired form, for example, the form of a rectangular parellelepiped by cooperation of the bottom tapping unit80and at least one pair of, in the embodiment, three pairs, of conveyor units91which are controlled so as to hold one or a plurality of bags and so that a rotational speed thereof is synchronized with the transfer speed of the bags, from the bag filling step (5) to the aeration/temporary seal step (8), as shown inFIG. 11. As the result of application of the above-described shaping, collapse of packaged products is avoided when the products are laid out flat.

The conveyor units91are supported on bearing members92disposed on the machine base1at predetermined intervals so that guide bars93are movable forward and rearward in a direction perpendicular to a direction (x) in which the bags are fed, as shown inFIGS. 12 and 13. Side conveyors98are mounted on a base94fixed to distal ends of the guide bars93. Reference numeral96designates a ball screw whose rotation is controlled by a servomotor drive unit95. The ball screw96has a distal end which is rotatably mounted on the base94. In the side conveyor98, plastic chains100extend between pulleys99disposed in parallel to the feed direction (x) of the bags at predetermined intervals. The side conveyors98are configured to synchronize rotational speeds of the plastic chains100with the transfer speed of the bags. The side conveyors98are disposed at the front and the back of the passing bag respectively and are configured to be rotated in the same direction as the feed direction (x) of the bags, as shown inFIG. 13.

Movable Bag-Mouth Auxiliary Opening Unit

A movable bag mouth auxiliary opening unit105includes a base106on which are mounted small-sized suckers107and bag mouth pressing members108closing the bag mouth other than an open portion into which an aeration nozzle is insertable as shown inFIGS. 11 and 14. The base106is configured to be movable forward and backward by driving an actuator (not shown). The actuator is configured to be reciprocable by a servomotor drive unit (not shown) between the vibrating/gas filling step (7) and the deaeration/temporary seal step (8). The sucker107and the bag mouth pressing members108are disposed so as to correspond to the front and the back of the bag respectively.

A movable bag mouth auxiliary opening unit105is configured so that part of the bag mouth is opened by an adsorption action of suckers107provided at both sides of the bag so as to be movable forward and backward, with the result that a deaeration nozzle110is insertable into the bag and so that the part of the bag mouth other than the opened part is closable.

In the deaeration/temporary seal step (8), the deaeration nozzle110is inserted into the bag to remove air remaining in the bag and is then pulled out of the bag, and thereafter, the bag is held by a temporary heater112of a temporary seal unit so that temporary seal is applied to the bag.

The seal unit includes a first sealing unit installed at the first sealing step (9) and a second sealing unit installed at the second sealing step (10). Heat seals are applied to a part of the bag where the temporary seal has been applied, by heaters113and114of the first and second sealing units respectively.

A cooling seal unit is configured to cool the part of the bag where heat seal has been applied by the seal unit, by cooling lever115as well known in the art.

Thus, the track gas-filling packaging machine according to the invention is constructed so that:

a size and a type of the packaging bag and a type of the article are entered on the operation panel2;

in the bag feeding step (1), a number of packaging bags set in the magazine31in a stacked state are turned up one by one from a top by the sucker24of the bag replenishing unit22thereby to be picked up and then passed to the bag chuck27, the sucker24being controlled so as to be moved in an up-down direction, and the packaging bag grasped by the bag chuck27is transferred to the adjacent bag positioning unit35to be thrown into the guide of the positioning unit, and the packaging bag is positioned by automatically adjusting positions of the side guides36and37corresponding to the bag width and positions of the front end guide40and the rear end guide38at the bag mouth side corresponding to a bag length based on the entered data, and the packaging bag in the guide is gripped by a chuck48of the bag supply unit45and is held by a cramp56of a cramp unit50standing by above with the bag mouth up to be sent from the cramp56to the grips11standing by at the bag placing step;

in a bag opening/inflating step (4), the bag mouth is opened by an adsorption action of suckers63and inflating the bottom of the bag by the adsorption action of the suckers63;

in an article filling step (5), a synchronous funnel77, which is controlled for up-down movement and horizontal movement in synchronization with transfer of the bag to be inserted into the bag is lowered to be inserted into the bag, is lowered, and a receiving member83of a bottom tapping unit80is applied to the bottom of the bag, whereby the bag is filled with a predetermined amount of article while the bottom is tapped so that the article is helped to fall,

wherein an inert gas is continuously discharged from a gas discharge nozzle78provided on the synchronous funnel77into the bag, during a period from a last moment of the filling operation to a plurality of subsequent steps. The bag is shaped into a desired shape by a cooperative work of the bag tapping unit80and a shaping unit provided with at least a pair of conveyor units91which are controlled so as to hold one or a plurality of packaging bags and so as to be controlled so that a rotational speed synchronizes a transfer speed of the packaging bag, during a period from the bag filling step (5) and to the deaeration/temporally sealing step (8), and the funnel77and the gas-filling nozzle78are caused to get out of the bag and a part of the bag mouth is kept open by the adsorption action of the suckers107, while the bag is moved to the deaeration/temporarily sealing step (8),

in a deaeration/temporarily sealing step (8), a deaeration nozzle110is inserted into the bag to remove air remaining in the bag, causing the deaeration nozzle110to get out of the bag, holding the bag mouth by a temporary heater112so that a temporary seal is applied to the bag mouth;

in a first seal step (9) and a second seal step (10), heat seal is applied to a temporarily sealed part of the bag; and

in a seal cooling/bag removing step (11), the heat-sealed part is cooled and the bag (a′) as a product is removed outside the system, whereby a work of changing related apparatus with change in the bag size can full-automatically be carried out.

The grips11are opened in the point seal step (3) to discharge the bag outside the system when a bag supported by the grips11does not have a predetermined height, when a chuck of a zipper of a zippered bag is undone or when the bag is supported by only one grip11. Furthermore, the grips11are opened in the first seal step (9) to discharge the bag outside the system when the bag supported by the grips11is defective in the opening of the bag mouth or in the inflating of the bag. Still furthermore, when the article filling the bag contains any metal, the grips11are opened in the first seal step (9) based on a detecting operation of a metal detector (not shown), whereby the bag is discharged outside the system.

The bag filled with the article weighs 15 to 20 kg, and there is a possibility that an upper part of the bag may stretch when supported by only the grips11. In view of this, a group of conveyors120are disposed to support the bottom of the bag from the first seal step (9) to the cooling/discharge step (11). Reference numeral121designates a discharge conveyor.

Since the operation of the track gas-filling packaging machine P according to the invention is described in relation (9) to the construction of the main apparatus and the units, the description of the operation will be eliminated.

The foregoing description and drawings are merely illustrative of the present disclosure and are not to be construed in a limiting sense. Various changes and modifications will become apparent to those of ordinary skill in the art. All such changes and modifications are seen to fall within the scope of the appended claims.