JP2010143613A - Stretch packaging method and stretch packaging machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stretch packaging method and a stretch packaging machine each capable of correctly packaging an object to be packaged correspondingly to a placement position where the object to be packaged is placed even if the object to be packaged is placed at any position in the width direction of an article placement part of an carry-in means. <P>SOLUTION: Displacement L between the center of the width direction of a carry-in means and the center of the width direction of an object W to be packed placed on the carry-in means is detected, a hanging position of a film which is hung to the packaging part by a film transfer mechanism on the basis of detect data, folded parts at right and left ends opposing the pay-out direction of the film out of external peripheries of the film covering the upper face of the object to be packaged is folded by a first packaging step which moves a pair of folded plates 8, 8' which are independently driven to the vicinity of the end of the object to be packaged, and a second packaging step which moves a pair of the folded plates toward the central direction of the object to be packaged from the ending position of the first packaging step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a stretch wrapping method and a stretch wrapping machine for wrapping using a stretch film, and more specifically, folds an end portion of a film for wrapping an object to be packaged (a state in which an article is accommodated in a tray) into the bottom side of the object to be packaged. The present invention relates to a folding mechanism.

  In a conventional stretch wrapping machine, when an operator places an article to be packaged on an article placement unit, the means for carrying the article to be packaged placed on the article placement unit is directed to an elevating mechanism (elevator) in the packaging machine. And then the object to be packaged is pushed up by the elevating mechanism toward the film stretched over the packaging part directly above the elevating mechanism, and the upper surface of the object to be packaged is covered with the film, and the outer peripheral edge of the film Folds the wrapping material to the bottom side of the package, the fold in the left-right direction and the fold in either the front or rear direction are advanced at the same time, and remains when the package is discharged (either the front or the back) ) Is folded, and the end of the last folded film is heat-sealed to complete the packaging (see, for example, Patent Document 1).

  However, when the placement position of the article to be packaged on the article placement section is placed in one of the width directions, the left and right sides of the film in the length direction covering the upper surface of the article to be packaged The object to be packaged is pushed up to a position biased to either side, and as a result, the outer peripheral edge of the film covering the upper surface of the object to be packaged cannot be correctly folded to the bottom side of the object to be packaged, resulting in defective packaging. Alternatively, in the case of a small-sized package, even if one end of the left and right folding plates and the end of the package are greatly separated and the folding plate moves in the direction of the packaging, the folding plate There is a gap between the end of the package and the folding plate without reaching the lower side of the package, and this gap prevents one of the folding plates from supporting the package, Trouble that falls (turns over) occurs.

  Therefore, in order to prevent the occurrence of the above trouble, the worker must perform the placing work while paying attention to place the article to be packaged in the substantially central part in the width direction of the article placing part, For the operator, the work of placing the article to be packaged on the substantially central portion of the article placement portion while paying attention is a burden and troublesome.

  In order to solve the above problem, there is also a packaging machine including a centering device that moves and corrects an article to be packaged placed on the article placement unit to a substantially central portion in the width direction of the article placement unit. The centering device is configured so that the tray slides in the infeed portion or the centering portion due to the material of the tray that accommodates the article to be placed, the freezing of the tray itself, and the grease of the product attached to the bottom surface of the tray. There is a problem that a phenomenon that cannot be performed occurs. And the centering defect has a problem that problems that should be solved originally occur, such as defective packaging, crushing of an object to be wrapped by a folding plate, and falling of the object to be wrapped.

JP 2005-119696 A

  The present invention has been made in view of the above-described problems of the prior art, and the object of the present invention is that the placement position of the article to be packaged placed on the article placement portion of the carry-in means is any in the width direction. Provided is a stretch wrapping method and a stretch wrapping machine capable of correctly wrapping the packaged object in accordance with the mounting position where the packaged object is mounted even at the position.

  In order to achieve the above object, the packaging method of the present invention stretches a film cut to a predetermined length at a predetermined position of a packaging machine by a film transfer mechanism, and on the other hand, is orthogonal to the film transfer direction of the film transfer mechanism. The article to be packaged carried in by the carrying means arranged is pushed up from below the stretched film by the lifting mechanism, and the left and right and front and rear ends of the film are folded to the bottom side of the article to be packaged. In the packaging method, a detection step of detecting a deviation between a center in the width direction of the carry-in means and a center in the width direction of the package to be packaged placed on the carry-in means, and a lateral width of the package, Based on the detected data, a film stretching step for adjusting the stretching position of the film stretched on the packaging portion by the film transport mechanism; And a pair of folding plates opposed to the film feeding direction (left and right side portions) of the outer peripheral edge of the film. A first wrapping step for independently moving the wrapping plate to a position near the end of the package, and moving the pair of folding plates by a predetermined amount from the end position of the first wrapping step toward the center of the package And a second packaging step. (Claim 1)

The pair of folding plates are moved independently of each other. And the movement start of the pair of folding plates in the first packaging step may be either the method of starting the movement at the same time or the method of starting the movement with a time difference, and both the former and the latter are moved at the same speed. Alternatively, there may be mentioned a method of moving with a speed difference. For example, if both folding plates have the same speed, the folding plate with the longer moving distance starts moving first, and when the remaining distance becomes substantially the same as the other shorter distance, the other folding plate The plate starts to move, and both folding plates reach the position near the end of the package at about the same time, or both folding plates are moved at the same time and moved simultaneously to reach the specified position at the same time. Any method may be used.
Further, the predetermined amount movement in the second packaging step is not limited to the same amount of movement from the end position of the first packaging step (position near the end of the package) toward the center of the package, For example, the movement amount (folding amount) of the pair of folding plates (left and right folding plates) varies depending on the shape of the tray (package).

According to the above means, the position of the article to be packaged (position in the width direction of the carry-in means) placed on the article placing portion of the carry-in means for transporting the package to the lifting mechanism in the packaging machine is detected by the detection means, Based on the detection data, the length of the film that wraps the article to be packaged is determined, cut into a predetermined length, and transported and stretched to the packaging portion (substantially above the lifting mechanism). At this time, the film cut into a predetermined length is substantially coincident with the approximate center of the object to be packaged supported by the lifting mechanism according to the mounting position of the object to be packaged. The transfer is stretched to the position where Thereby, the length from the end of the package to the outer peripheral end of the film (the length of the turn-back margin of the film folded on the bottom side of the package) is substantially the same on both the left and right sides. It will be. And the film which covers the upper surface of a package is a pair of folding plates (left and right folding plates) arranged facing the feeding direction of the film, and a folding plate arranged to intersect the pair of folding plates substantially at right angles The three sides of the film are folded to the bottom surface side of the package by the (rear folding plate), and the remaining periphery is folded to the bottom surface of the package by the discharging operation of the package.
Further, more stable packaging can be realized by changing the folding amount of the left and right end portions of the film depending on the shape of the package (tray).

The folding of the film by the pair of folding plates moves to the position near the end of the packaged object to which the pair of folding plates respectively correspond in the first packaging step. That is, when the article to be packaged is arranged to be deviated in any direction (left or right direction) in the width direction with respect to the center line in the width direction of the conveying means, a pair of folding plates from the end of the article to be packaged In the first packaging step, the pair of folding plates move toward the corresponding end portions of the objects to be packaged, respectively. And since both folding plates move to the position near the edge of the package, both folding plates move the same amount toward the center of the package in the second packaging step, so the outer edge of the film The parts are folded evenly.
Therefore, when folding the film outer edge, the pair of folding plates reliably support the package, and the single support phenomenon by only one folding plate does not occur, and the package falls or the package is wrapped. A stable packaging can be realized without crushing between the two.
Further, even when the article to be packaged is placed on the article placement section of the carry-in means so as to be biased with respect to the center in the width direction, it can be packaged corresponding to the placement position. The trouble of paying attention to the placement position is eliminated.

The first packaging step and the second packaging step in which the outer peripheral end of the film covering the top surface of the packaged object is folded to the bottom surface side of the packaged product may have a pause time between the two steps. The first packaging step and the second packaging step may be carried out continuously without providing the above (claim 2).
According to the above means, the packaging time per unit can be shortened, and thereby the packaging operation (number of packaging) per unit time can be increased.

The stretch wrapping machine that performs the stretch wrapping method stretches a film cut to a predetermined length at a predetermined position of the wrapping machine by a film transfer mechanism, and on the other hand, is orthogonal to the film transfer direction of the film transfer mechanism. The article to be packaged carried in by the carrying means arranged is pushed up from below the stretched film by the lifting mechanism, and the left and right and front and rear ends of the film are folded to the bottom side of the article to be packaged. In the stretch wrapping machine, a driving means for independently sliding a pair of folding plates arranged opposite to each other in a direction orthogonal to the carrying-in direction of the packaging object, and the carrying-in direction of the packaging object placed on the carrying-in means Detecting means for detecting an end position in a direction orthogonal to the position of the package, based on end position data of the package on the loading means detected by the detecting means. The pair of folding plates are moved and brought close to both end positions of the detected object to be packaged by the driving means, and the pair of folding plates are further moved toward substantially the center of the object to be packaged. The structure is characterized in that the part is folded into the bottom surface side of the article to be packaged (Claim 3).
The detection means for detecting the placement position of the article to be packaged is arranged with two sensors at a substantially central position on the front side of the article placement section of the carry-in means, and both sensors are arranged in the article placement section width direction from the substantially center position The sensor is arranged on both sides before the article placement part of the carrying means by moving the sensors in the direction away from each other in the direction of both outer edges of the article, or detecting both end positions of the article to be packaged. For detecting the positions of both ends of the article to be packaged by moving the position from the standby position (initial position) toward the center in the width direction of the article placement section, or a plurality of optical sensors in front of the article placement section in advance. May be arranged at equal intervals in the width direction and detected by the number of the light sensors blocked and the positions of both ends thereof, or detected by a captured image using a camera.

  According to the above means, even when the product is placed on the article placement part of the carry-in means with a deviation from the center in the width direction, the movement amount of the pair of folding plates is adjusted corresponding to the placement position. Since the packaging can be performed, the troublesome work for the operator while paying attention to the placement position of the article to be packaged is eliminated. Thereby, stable packaging can always be performed.

  In addition, the film transfer mechanism is a film cut to a predetermined length based on the detection data of the detection means, and a film centered in the longitudinal direction of the film to be packaged on the lifting mechanism. You may comprise so that it may transfer to the position which overlaps substantially the center (Claim 4).

  According to the above means, the position where the film is cut to a predetermined length and transferred and stretched to the packaging part is changed according to the placement position of the package object, and the length of the film is always at the approximate center position of the package object. It is stretched so that the approximate center of the direction overlaps. Thereby, the length from the end of the package to the outer peripheral end of the film (the length of the turn-back margin of the film folded on the bottom side of the package) is substantially the same on both the left and right sides. It will be. Thereby, a to-be-packaged object can be packaged reliably.

According to the stretch wrapping method of the present invention, the stretch position of the film cut to a predetermined length is adjusted based on the position placed on the article placement portion of the carry-in means according to the configuration described in claim 1, and The folding of the outer peripheral edge of the film covering the package is performed by moving the pair of folding plates independently, and folding the package from the position near the edge of the package toward the center by a predetermined amount. Both plates are securely supported by the plate. Accordingly, it is possible to solve the problem of the fall of the article to be packaged due to the one-side support, which occurs in the conventional packaging method in which the pair of folding plates are moved together with a single power, or the object to be packaged is crushed.
Further, according to the above means, the packaging time per unit can be shortened, and thereby the packaging operation (the number of packages) per unit time can be increased.
Furthermore, according to the stretch wrapping machine according to claim 3, a pair of folding is performed corresponding to the placement position even when placed on the article placement portion of the carry-in means with a deviation from the center in the width direction. Since the package can be packaged by adjusting the amount of movement of the plate, the troublesome work performed by the operator while paying attention to the placement position of the article to be packaged is eliminated. Thereby, stable packaging can always be performed.
Furthermore, according to the configuration of claim 4, the length to the outer peripheral end of the film protruding downward from the end of the package (the length of the turn-back margin of the film folded on the bottom side of the package) is The left side and the right side have substantially the same length, so that an article to be packaged can be reliably packaged.

Today, generally known elevator-type packaging methods use a lifting mechanism (elevator) to push up an object to be wrapped from a film stretched on a packaging part, and thereby the upper surface of the object to be wrapped is placed on the film. And a pair of folding plates (left and right folding plates) arranged opposite to the feeding direction of the film, and after folding that is arranged so as to be substantially orthogonal to the pair of folding plates. The other side is folded to the bottom side of the package by a front folding roller when the package is discharged, and the pair of folding plates (left and right folding plates) is a single unit. Operate together with a single power and are placed on the placement position of the article to be packaged placed on the carry-in means, for example, one side (left side or right side) in the width direction of the carry-in means. It has always been to move only a certain amount regardless.
In the stretch wrapping method of the present invention, the folding position of the film in the above-described elevator type wrapping method and the stretch position of the film stretched on the packaging portion are determined by the mounting position with respect to the carrying-in means for carrying the article to be packed into the packaging machine. In addition, the folding operation of the pair of folding plates (left and right folding plates) is performed independently and corresponds to the above-described placement position.

  Specifically, a detection step for detecting a deviation between a center in the width direction of the carrying-in means and a center in the width direction of the article to be packaged placed on the carrying-in means and a lateral width of the article to be packaged, and the detection Based on the obtained data, a film stretching step for adjusting the position of the film stretched on the packaging portion by the film transport mechanism, and the object to be packaged is pushed up by the lifting mechanism from below the film stretched on the packaging portion. A first step of moving the pair of folding plates facing the feeding direction of the film to a position near the end of the packaged object, out of the outer peripheral edge of the film, covering the upper surface of the packaged object with the film A packaging step; and a second packaging step of moving the pair of folding plates by a predetermined amount from the end position of the first packaging step toward the center of the package.

  And the packaging by the film which cut the to-be-packaged item into the predetermined length, the folding of the left and right end parts by the first packaging step and the second packaging step, the folding of the rear side end part by the back folding plate, and the The first wrapping step and the second wrapping step are completed in a pause time during which the operation of the pair of fold-in plates is temporarily suspended between the two steps. (Momentary stop) may be provided, but in consideration of workability and productivity, it is effective to perform the second packaging step continuously after the first packaging step without providing the downtime. .

  In the second packaging step, the pair of folding plates (left and right folding plates) move from the position near the end of the package to the center of the package, and the end of the film is moved to the bottom of the package. Although the pair of folding plates move independently, the amount of movement is not limited to the same amount (length), for example, depending on the shape of the tray (package). The amount of movement of the folding plate may be changed, so that packaging corresponding to the tray shape can be performed.

Hereinafter, an example of an embodiment of a stretch wrapping machine that performs the wrapping method will be described with reference to the drawings.
FIG. 1 shows an outline of a stretch wrapping machine A using a stretch film that is generally known today, and a product b is placed on a flat tray a on the front side of the machine frame 1, that is, on the front front side (right side in the drawing). An elevator (lifting / lowering) in which a placing portion 2 for placing the placed article W to be placed is arranged, and the article W to be packaged placed on the placing portion 2 is placed inside the machine frame 1 by a pusher conveyor (carrying means) 3. Mechanism) Transports to 4. In addition, the mounting unit 2 is configured as a weighing pan of a weighing unit that measures the weight of the article W to be packaged.
In addition, the article W to be packaged placed on the placement section 2 was placed on the placement section 2 on the side (front side of the placement section) opposite to the direction of being carried into the machine frame 1. Two detection means 14 for detecting the left and right end positions in the width direction (direction orthogonal to the transport direction) of the article W to be packaged are provided at substantially the center position of the placement unit 2 described above.
The detection means 14 is composed of a photosensor, and when the article W to be packaged is placed on the placement portion 2, the detection portion provided at the substantially central position is both at a predetermined speed in the width direction of the placement portion. The sensor moves in a direction away from each other toward the outer edge, detects the distance to the end of the package W (light is blocked: dark on), and the detection distance to both ends is described later. It transmits to CPU of a control part. The CPU detects the position data (coordinates) of the left and right ends where the package W is placed from the detection distance to the both ends in the width direction of the package W and the positions of both ends, and the CPU The width of the article W is calculated. In addition, when calculating the lateral width of the said package W by moving the detection means 14 from the both outer edge parts of the mounting part 2 to a substantially central position, the reference length of the mounting part and the moving speed of the detection part You may use the method of calculating from the both-ends position of the said to-be-packaged object W detected. When the latter is a large tray and the former is a small tray, the width of the package W and its coordinates can be obtained in a short time. The operation of the detection unit may be either one of the operations or a combination of the former and the latter.

  A packaging part 5 is provided above the elevator 4, and a film roll 6 used for packaging is set on the side of the packaging part 5 (in a direction perpendicular to the pusher conveyor) and is fed out from the film roll 6. The film 6 ′ is pulled out by the film transfer mechanism 7, cut to a predetermined length, transferred to the packaging unit 5, and stretched and held horizontally.

  The elevator (elevating mechanism) 4 is composed of an elevating part and a head part that supports and supports an object to be packaged, and the head part is refracted by contact with the left and right folding plates 8 and 8 ', and the film end part The folding operation is not hindered. That is, the movement of the left and right folding plates 8 and 8 'refracts the head portion supporting the left and right side portions of the package W and folds the end of the film toward the bottom surface of the package W, and at the same time The left and right folding plates 8 and 8 ′ support the bottom surfaces of the left and right side portions of the package W in place of the head that has been made.

  The packaging part 5 includes a left and right folding plate (a pair of foldings) that folds the end of the film 6 ′ located above the film transfer mechanism 7 and covers the top surface of the packaged object W to the bottom side of the packaged object W. Plate) 8, 8 ', the rear folding plate 9, and the rear folding plate 9 are positioned above the rear folding plate 9 to discharge the package W in which the left and right and rear film ends are folded into the bottom side of the package W. The discharge pusher 10 and a front folding roller 11 that folds the front film end portion are disposed at the front position in the sliding direction of the discharge pusher 10.

The film transfer mechanism 7 includes a pair of upper and lower endless elastic belts 7a and 7b that sandwich a side end portion in the width direction of a film 6 'fed out from a film roll 6, and a lower elastic belt 7b as an upper elastic belt. The clamp plate 7c press-contacts to the 7a side, and the contact plate 7d disposed in the upper elastic belt 7a. The pair of endless elastic belts 7a and 7b are configured such that the forward path side is driven and rotated in the same direction so that the film 6 'can be held and conveyed.
The clamp plate 7c disposed in the lower elastic belt 7b is divided into a plurality of (for example, three) longitudinal directions, and is moved to the forward path side of the lower elastic belt 7b by an electromagnetic solenoid (not shown). On the other hand, it is configured to be pressed / separated. The divided clamp plates 7c are sequentially switched from the pressure contact state to the separation state in accordance with the film folding operation, and the film clamping is released.

  The film transfer mechanism 7 is fed out from the film roll 6 to a predetermined length based on the position data (coordinates) of the left and right ends of the package W detected by the detection means 14 and the width dimension of the package W. The drive is controlled so that the film 6 ′ cut in a straight line is transported and stretched almost directly above the article W to be packaged supported on the elevator 4.

The left and right folding plates 8 and 8 'are each provided with an independent drive mechanism (see FIG. 5), the position data (coordinates) of the left and right ends in the width direction of the package W detected by the detection means 14 and the data Based on the width dimension of the article W to be packaged, movement from each standby position toward the position data (coordinates) of the left and right ends of the article W to be packaged is controlled by the CPU.
The left and right folding plates 8 and 8 'are composed of two upper and lower plates 8a and 8b, and a rear folding plate 9 is slidably inserted between the left and right upper plates 8a and 8b. . The left and right folding plates 8 and 8 'are not limited to the flat and hollow strip shape shown in the figure, but may be configured as a single plate, and the rear folding plate may be slidably disposed on the left and right folding plates. The control content of the movement of the left and right folding plates 8 and 8 'will be described later.

  Further, in front of the front folding roller 11, a heater portion 12 for heating and closely contacting an overlapping portion of the end portion of the film folded to the bottom side of the package W, and a discharge means 13 are disposed in front of the heater portion 12. ing.

FIG. 5 is a block diagram showing the electrical configuration of the stretch wrapping machine described above, and the wrapping mechanism control section 15 mainly controls the mechanism section of the wrapping machine and is controlled by the CPU 16.
The CPU 16 has a ROM 17, a RAM 18, an operation unit 19, a detection unit 20 (detection means 14), a display unit 21, a mechanism drive unit 22, an elevator motor 23, a carry-in motor 24, a film transport motor 25, and a left folding via a bus 16 a. A plate drive motor (drive means) 26, a right folding plate drive motor (drive means) 26 ', a rear folding plate drive motor 27, and a product discharge motor 28 are connected, and the operation timing of each mechanism section and its control are controlled by a timer 29. To do.
The ROM 17 stores a program executed by the CPU 16 and a packaging control data table.
The RAM 18 stores various registers and flag areas used when the CPU 16 executes the packaging control data table stored in the ROM 17.
The operation unit 19 includes various switches for starting and stopping the apparatus and a keyboard for inputting data.
The detection unit 20 includes a pair of left and right photosensors that detect the positions of the left and right end portions of the article W to be packaged placed on the placement unit 2, and moves toward the center in the width direction at a predetermined speed. It is configured.
The display unit 22 is composed of a touch panel, and displays input data, preset data, and various messages based on commands from the CPU 16, and is also called an alias console.

  The mechanism drive unit 22 is a circuit for driving each mechanism unit of the packaging machine when packaging is performed, and when the parts related to the present invention are listed, the elevator motor 23 that operates the elevator 4 and the packaged item W are arranged. A carry-in motor 24 that operates the pusher conveyor 3 to be carried in, a film transport motor 25 that operates the film transfer mechanism 7, a left folding plate drive motor 26 that operates the left folding plate 8, and a right folding plate drive that operates the right folding plate 8 '. Motor 26 ′, rear folding plate drive motor 27 that operates the rear folding plate 9, and a discharge pusher 10 that discharges the package W with the left and right and rear film ends folded into the bottom side of the package W are operated. The drive of the product discharge motor 28 to be controlled is controlled.

  The timer 29 outputs the timer value to the CPU 16. The CPU 16 sets each mechanism unit control information set in advance to operate each mechanism unit (not shown: the operation of each mechanism unit and the time setting from the detection of an object to be packaged by the sensor to the start of the mechanism unit, Drive or movement amount and its sequence, etc.), the timer value, and sensors (not shown: for example, an article to be packaged placed on the article placement unit is placed on the elevator) Based on the output value of a sensor for detecting whether or not the object is transported and a sensor for detecting whether or not an article to be packaged is placed on the elevator when the elevator is raised and reaches the upper limit position). The film conveying motor 25, the left folding plate driving motor 26, the right folding plate driving motor 26 ', the rear folding plate driving motor 27, and the product discharge motor 28 are driven. That is, the mechanism drive unit 22 operates the elevator when packaging, the operation of the pusher conveyor 3, the transport operation of the film 6 ', the operations of the left and right folding plates 8, 8' and the rear folding plate 9, and the operation of the discharge pusher 10. The units are driven at the same timing. The operation timing of each mechanism unit and its control are not limited to those controlled based on the timer 29, and may be performed using an encoder. When control is performed using an encoder, the rotation shaft of the encoder is mechanically coupled to the rotation shaft of the elevator motor 23, and a pulse corresponding to the rotation of the elevator motor 23 is output to the CPU 16. The CPU 16 counts the pulses, and the mechanism drive unit 22 determines the film transport motor 25, the left folding plate drive motor 26, the right folding plate drive motor 26 ', the rear folding plate drive motor 27, and the product discharge motor based on the count value. 28 is driven. That is, the mechanism drive unit 22 operates the elevator when packaging, the operation of the pusher conveyor 3, the transport operation of the film 6 ', the operations of the left and right folding plates 8, 8' and the rear folding plate 9, and the operation of the discharge pusher 10. The respective parts can be driven at the same timing.

Next, the operation of folding the film 6 ′ and the folding of the left and right folding plates 8, 8 ′ will be described with reference to FIGS.
First, the width direction center O ′ of the package object W is a distance on the right side with respect to the center line O in the width direction of the conveyor on the placement portion 2 where the package object W is arranged on the start end side of the pusher conveyor 3. When placed by L, the positions of the left and right ends when the article to be wrapped W is placed are detected by the movement of the detection unit of the detection means 14, and the movement distance of the detection unit is transmitted to the CPU 16. . Since the placing section 2 also serves as a weighing pan of the weighing section, when the weighing is stable and the weight is determined, the pusher conveyor 3 is activated and the width W when the article W to be packaged is placed on the placing section 2. It is conveyed toward the elevator 4 while being in the position state in the direction, and is transferred onto the elevator 4. Thereby, even in the state of being mounted on the elevator 4, the center in the width direction of the package W is on the right side with respect to the center line in the width direction of the elevator 4 (lateral width in a direction perpendicular to the conveying direction of the pusher conveyor). Is supported by being shifted by a distance L. In addition, the height and length (length along the conveyance direction) of the package W are measured in addition to the weight measurement and the width dimension in the middle of the conveyance by the pusher conveyor 4, and the film is based on the measured values. The payout length is determined.

  The film 6 ′ cut to a predetermined length based on the measurement value of the package W is transported and stretched on the packaging unit 5 directly above the elevator 4 by the film transfer mechanism 7. At this time, the film transport motor 25 for operating the film transport mechanism 7 is controlled by the CPU 16 based on the position data of the left and right end portions of the package W detected by the detection means 14, and the film transport motor 25 is controlled in the length direction of the film 6 '. The center is conveyed and stretched so as to be positioned at a position substantially directly above the center O ′ in the width direction of the article W to be packaged mounted on the elevator 4. That is, the film 6 'is centered and stretched.

  The article W to be packaged placed on the elevator 4 is pushed up from below by the film 6 ′ stretched on the packaging part 5 by raising the elevator 4, and the upper surface of the article W to be wrapped is covered with the film 6 ′. At this time, since the film 6 'and the package W are centered as described above, the length from the end of the package W to the outer peripheral end of the film 6' protruding downward is the left side and the right side, The front side and the rear side have substantially the same length.

After the upper surface of the article to be wrapped W is covered with the film 6 ′ by the elevator 4, the left and right folding plates 8, 8 ′ slide toward the center of the article to be wrapped W and the left and right ends of the film 6 ′. Is folded into the bottom side of the article W to be packaged.
Here, the left and right folding plates 8 and 8 ′ are first moved from the standby position to the positions near the left end and the right end of the article W by the independent drive motors 26 and 26 ′ (first packaging step), Next, a predetermined amount is slid toward the center of the article W to be packaged (second packaging step), and the left and right ends of the film 6 ′ are folded to the bottom surface side of the article W to be packaged.

  The first packaging step is preparation for stably and surely folding the film end, and the left and right folding plates 8 and 8 ′ are arranged in accordance with the state in which the article to be wrapped W is placed on the placing portion 2. The object W is slid to the position in the vicinity of the end of the package W. That is, as shown in FIG. 4, the left folding plate 8 is a distance L1 to the vicinity of the left end of the package W, and the right folding plate 8 'is a distance L2 (L1 to the vicinity of the right end of the package W. Slide> L2). The sliding of the left and right folding plates 8 and 8 'may start simultaneously, but the left folding plate 8 having a long moving distance starts sliding first, and the remaining distance is the right folding plate 8'. The right folding plate 8 'starts to slide and reaches the vicinity of the left and right end portions of the packaged article W at substantially the same time. Note that the sliding of the left and right folding plates 8 and 8 'in the first packaging step is not limited to the above method, and the control of the right and left folding plates 8 and 8', such as a method of simultaneously starting movement by changing the moving speed of the left and right folding plates 8 and 8 ', is appropriately performed. Is possible.

The left and right folded plates 8 and 8 ′ positioned near the end of the package W in the first packaging step are slid a predetermined distance (same distance) toward the center of the package W in the second packaging step. The film is moved and the left end and the right end of the film 6 ′ are folded to the bottom side of the package W. That is, as shown in FIG. 4, the left folding plate 8 moves a distance L1 ′, and the right folding plate 8 ′ moves a distance L2 ′ (L1 ′ = L2 ′). Thereby, the amount of folding of the left and right end portions of the film 6 ′ by the left and right folding plates 8, 8 ′ becomes substantially the same, and a stable packaging basis is formed.
The amount of movement of the left and right folding plates 8, 8 ′ in the second packaging step is not necessarily the same distance. For example, the folding amount of the left and right end portions may be changed according to the shape of the tray of the article W to be packaged. Good.

  The left and right folding plates 8 and 8 'are supported by the left and right folding plates 8 and 8' by sliding a predetermined amount from the position near the end of the package W in the second packaging step toward the center. At the same time, the elevator 4 starts to descend.

Following the folding of the left and right end portions, the rear folding plate 9 slides in a horizontal state toward the front, and the rear end portion of the film 6 ′ is folded to the bottom surface side of the package W.
Subsequent to the sliding of the rear folding plate 9, the discharge pusher 10 is operated to push the article W to be packaged with the left and right end portions and the rear end portion folded to the bottom side toward the heater portion 12. By the extrusion by the discharge pusher 10, the front end portion of the film 6 ′ is folded by the front folding roller 11 to the bottom surface side of the package W.
The packaging object W, in which the left and right end portions, the rear end portion, and the front end portion of the film 6 ′ covering the top surface of the packaging object W are folded to the bottom surface side, is discharged to the heater unit 12 by the discharge pusher 10. When passing through the film, the end of the folded film is heated and brought into close contact. Then, it is discharged from the heater section 12 to the discharge means 13.

  Even when the center of the article W to be packaged is shifted in the left-right direction with respect to the center in the width direction of the mounting portion by the stretch wrapping machine having the above-described configuration, the film 6 ′ cut into a predetermined length is the film transfer means. 7 is centered according to the position placed by 7 and transported and stretched. The left and right end portions of the film 6 'covering the top surface of the article to be packaged by the lift of the elevator are surely placed on the bottom side of the article to be packaged by the operations of the first packaging step and the second packaging step of the left and right folding plates 8, 8'. It can enter and stably support the package, and the right and left end portions of the film 6 'can be stably folded.

The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.
(1) The illustrated stretch wrapping machine is a pre-loading / pre-discharge type wrapping machine in which the supply side of the package and the discharge side of the packaged package are the same side. It may be a stretch wrapping machine.
(2) The detection means in the embodiment is configured such that the detection units are provided on both the left and right sides, and the detection unit detects the end of the package by moving in the central direction at a predetermined speed. Without being limited, for example, a plurality of photosensors are provided at equal intervals on the front side of the placement unit, and by the number of the photosensors blocked and both end positions, both end positions on which the object to be packaged is placed, Any method such as a method of detecting the width dimension of the object to be packaged or a method of detecting by imaging with a camera may be used.
(3) Although the left and right folding plates in the embodiment are configured with upper and lower two plates, a single plate may of course be used.

The schematic diagram showing an example of a stretch wrapping machine according to the present invention. The top view of a packaging part. The perspective view which shows the structure of a right-and-left folding plate, a back folding plate, and a discharge pusher. Operation | movement explanatory drawing of a right-and-left folding plate. The block diagram which shows the electrical constitution of a stretch wrapping machine.

Explanation of symbols

A ... Stretch wrapping machine W ... Package
2 ... Placement part 3 ... Pusher conveyor (carrying means)
4 ... Elevator (elevating mechanism) 5 ... Packaging
6 '... film 7 ... film transfer mechanism 8, 8' ... left and right folding plate 14 ... detection means 26, 26 '... folding plate drive motor (drive means)
L1, L2 ... First packaging step L1 ', L2' ... Second packaging step

Claims (4)

A film cut to a predetermined length is stretched at a predetermined position of the packaging machine by a film transfer mechanism, and on the other hand, an object to be packaged is moved up and down by a loading means arranged orthogonal to the film transfer direction of the film transfer mechanism. In the packaging method of pushing up from the lower side of the stretched film by a mechanism and folding the left and right and front and rear end portions of the film on the bottom side of the packaged object, and packaging the packaged object,
A detecting step for detecting a deviation between a center in the width direction of the loading means and a center in the width direction of the packaged object placed on the loading means, and a lateral width of the packaged object;
Based on the detected data, a film stretching step for adjusting the stretching position of the film stretched on the packaging portion by the film transport mechanism;
Pushing up the object to be packaged from below the film stretched on the packaging part with an elevating mechanism, and covering the upper surface of the object to be wrapped with the film,
A first packaging step of independently moving a pair of folding plates opposed to the feeding direction of the film out of the outer peripheral edge of the film to a position near the end of the article to be wrapped;
A second packaging step of moving the pair of folding plates from the end position of the first packaging step by a predetermined amount toward the center of the package;
A stretch wrapping method characterized by comprising:   The stretch packaging method according to claim 1, wherein the first packaging step and the second packaging step are continuously performed. A film cut to a predetermined length is stretched at a predetermined position of the packaging machine by a film transfer mechanism, and on the other hand, an object to be packaged is moved up and down by a loading means arranged orthogonal to the film transfer direction of the film transfer mechanism. In a stretch wrapping machine that pushes up from below the stretched film by a mechanism and wraps the package by folding the left and right and front and rear ends of the film on the bottom side of the package,
Driving means for independently sliding a pair of folding plates arranged opposite to each other in a direction perpendicular to the carrying-in direction of the article to be packaged;
A detecting means for detecting an end position in a direction perpendicular to the carrying-in direction of the article to be packaged placed on the carrying-in means;
Based on the end position data of the article to be packaged on the carrying means detected by the detection means, the pair of folding plates are moved and brought close to the positions of the both ends of the article to be packaged detected by the driving means, and A stretch wrapping machine, wherein a folding plate is moved toward substantially the center of the article to be packaged, and the end of the film is folded to the bottom side of the article to be packaged.   The film transfer mechanism includes a film cut to a predetermined length based on the detection data of the detection means, and the approximate center in the length direction of the film is approximately the center of an object to be packaged mounted on the elevating mechanism. The stretch wrapping machine according to claim 3, wherein the stretch wrapping machine is transported to a position overlapping with the stretch wrapping machine.

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