JP2727953B2 - Stretch packaging method and packaging machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretch wrapping method and a wrapping machine capable of providing a large overlapping area between film ends at a folded portion of a film on the bottom surface of an object to be wrapped.

[0002]

2. Description of the Related Art Conventional stretch wrapping machines include, for example, a stretch wrapping machine disclosed in Japanese Patent Application No. 5-42165.
The object to be packaged is lifted and pushed up against the packaging film tensioned at the packaging portion, and the front and rear folding plates and the left and right folding plates provided in the vicinity of the packaging portion are horizontally folded so that the front, rear, left and right sides of the packaging film can be moved. There is a configuration in which the end is folded toward the center of the bottom surface of the packaged object.

At the time of packaging, the above-mentioned stretch wrapping machine pushes up an object to be wrapped against a wrapping film tensioned in a wrapping section, and then, as shown in FIGS.
Left and right and front and rear folding plates 103, 10 provided near the packaging section
4 is simultaneously moved horizontally, moved deeply to the center of the bottom surface of the packaged object 101 and stopped, so that the left, right, front and rear ends of the packaging film 102 are folded into the bottom surface of the packaged object 101, and the folded package is further folded. The end of the film 102 is bonded by heat sealing.

[0004]

However, in the stretch wrapping machine described above, the left and right fold plates 103 and 104, which start the fold operation first, are moved deeply to the center of the bottom surface of the packaged object 101, and at that position. In order to fold the left and right ends of the film 102 by stopping, when the front and rear ends of the film 102 are folded and the packaging is completed, each end of the film 102 is folded so as to concentrate on one point at the center of the bottom surface of the article 101 to be packaged. Will be. Then, as described above, when the ends of the film 102 are concentrated at the center of the bottom surface of the article to be packaged 101, the left and right ends 102a and the front and rear ends 10a of the film 102 overlap and adhere to each other as shown in the package shown in FIG.
As a result of a decrease in the area of polymerization with 2b and a decrease in the length of bonding by heat sealing, a problem may occur that the bonded portion is easily peeled off after packaging.

[0005] Further, if the folding of the above-mentioned left and right folding plates is made shallow, the sticking stickers at the left and right ends of the film will not reach the center of the packaged object, and in this case, the adhesion of the packaging film also becomes weak. There is. SUMMARY OF THE INVENTION An object of the present invention is to provide a stretch packaging method and a packaging machine capable of widely and surely bonding a folded end of a film on a bottom surface of a packaged object.

[0006]

In order to achieve the above-mentioned object, a stretch packaging method of the present invention tensions a packaging film, pushes up an object to be packaged with respect to the packaging film, and covers the surface. In the stretch packaging method in which the front and rear sides of the packaging film are folded toward the center of the bottom surface of the packaged object by the left and right folding plates and the front and rear folding plates, and the overlapped films are heat-sealed, Folding in the direction of folding in any direction is a pair of films to be folded.
The side in the direction perpendicular to the side is only the center of the film width.
The left and right sides of the film are sandwiched and opened, and a pair of corresponding film sides are folded by a pair of folding plates so as not to be deepened, and a pair of film sides folded by a predetermined amount are folded.
Against it, in which pushed by blowing a pair of compressed air facing only to a substantially central portion of the pair of film edges portions folded in operation substantially simultaneous folding plate after the center of the bottom of the packed material.

Further , the above-mentioned stretch packaging method is performed.
Stretch wrapping machine for raising and pushing the wrapped object against the wrapping film tensioned in the wrapping section, and the fold operation of the front and rear fold plate and the left and right fold plate, the front and rear direction and left and right direction of the packaging film the side portion folding toward the center of the bottom of the packed material, the stretch wrapping machine for heat-sealing the overlapped films, packaging Phil
Front and rear grippers or packing
Of the left and right clamping devices that hold the left and right edges of the film
The side of the film in the direction perpendicular to the folding plate that operates first
Before and after gripping the gripper
A pair of folding plates having a form of a plurality of divisions including a central portion in the width direction , the folding operation being performed at one of the front and rear folding plates or the left and right folding plates, and stopping with a slight gap at the bottom central portion of the packaged object. A pair of opposing blowing means for blowing compressed air toward only substantially the center of the pair of film sides folded by the folding operation of the folding plate is not provided below.
Direction that is perpendicular to the pair of film edges
The left and right sides of the film are sandwiched only at the center of the film width.
The side part is open, and the operation of the folding plate to be folded later is almost
Simultaneously spraying by the spraying means is performed.
Sign .

In the above packaging machine, the spraying means may be provided on the folding plate itself. In addition, the stretch packaging machine of the present invention,
It is more effective to perform the blowing operation of the pair of blowing means substantially alternately between front and rear or between left and right.

[0009]

According to the stretch wrapping machine of the present invention constructed as described above, when the wrapped object is lifted and pushed up with respect to the wrapped film stretched in the wrapping section, the surface of the wrapped object is stretched. It will be in the state covered with the film. In addition, when the front and rear folding plates and the left and right folding plates are horizontally operated, and the front and rear sides and the left and right sides of the packaging film are folded toward the center of the bottom of the packaged object, one of the front and rear folding plates or the left and right folding plates is used. Is activated first, then the fold
Only about the center of the film edge folded in
To later be blown compressed air from the operating substantially simultaneously with one <br/> pair of blowing means of the folding plate for folding operation, the Fi
The side of the lum is pushed into the center of the bottom of the package.

[0010] The pressure due to the blowing of the compressed air, was folded by actuating the folding plate on the bottom surface of the packaged articles
The folded side of the film is further pushed toward the center of the bottom surface. In this state, the remaining folded side portion of the film is folded up to the center of the bottom surface of the packaged object by the folding plate operated later. At this time, the other film insertion side
Is the part pushed in toward the center of the bottom of the package.
It overlaps and closely adheres to the Lum insertion side via a large area. Then, the folded film sides are bonded by heat sealing.

In the case where the blowing means is provided on the folding plate itself, the blowing position of the compressed air by the blowing means moves along with the movement of the folding plate, and is sprayed from the moving position toward the center of the bottom surface of the packaged object to thereby make the film side. Part .

Furthermore, according to be carried out in a substantially alternate between or between the left and right front and rear blowing operation of the spraying means a pair, the left-right direction or the front and rear are folded on the bottom surface of the packaged articles at folding plate was activated first One side of a pair of film sides in the direction is folded by the spraying performed earlier and adheres to the bottom surface, and the other side is folded later by the spraying of the opposite side and adheres to the bottom surface. Then, the pair of film sides adhere to each other in a state where they are alternately overlapped with the bottom surface of the packaged object. Therefore, since the film side portions folded first adhere to the bottom surface, the film side portions folded by the folding plate operated later are folded in a state of being in direct contact with each other.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. 1 the present invention shows a stretch wrapping machine embodying, loading unit A the machine frame 3 to put put the items 1 are to be packaged
And a packaging section B on which the film 2 for wrapping the product 1 is horizontally fed and stretched is provided on the upper surface of the machine frame 3. A transport mechanism C for transporting the product 1 received from the loading section A to the packaging section B is supported by a driving mechanism D,
It can be moved horizontally and vertically within the machine frame 3,
After the transfer table C is horizontally moved by the horizontal operation section D1 of the drive mechanism D to the carry-in section A on which the product 1 is placed, the transfer table C is vertically moved by the vertical operation section D2 of the drive mechanism D in the carry-in section A. The merchandise 1 is received from the loading section A.

The transport table C on which the product 1 is placed is moved horizontally by the horizontal operation section D1 under the packaging section B on which the film 2 is horizontally fed and stretched. D2 moves vertically toward the film 2 of the wrapping part B. By these series of operations, the transport table C is moved horizontally and vertically from the loading section A to the packaging section B, and the goods 1 loaded into the loading section A by the transport table C are transported from the loading section A to the packaging section B. Then, the product 1 is configured to be pushed up and packaged on the film 2 of the packaging section B.

As shown in FIG. 2, the carry-in portion A is formed in a substantially comb-tooth shape by arranging a plurality of mounting rods 4 at appropriate intervals and connecting and supporting one end thereof. When a receiving portion 34 of the transport table C, which will be described later, passes between the mounting rods 4, the product 1 placed on the mounting rod 4 is received. The loading section A is mounted and supported via a supporting rod 6 on a measuring instrument 5 with a built-in load cell disposed in front of the machine frame 3, whereby the weight of the product 1 placed on the mounting rod 4 is measured. A label printer (not shown) issues the weight data and a label printed with the price calculated based on the weight data.

In the packaging section B, a front gripper F for holding the leading end of the film 2 and pulling it out from the film supply device E by a predetermined length is disposed so as to be horizontally movable above the loading section A on the front surface of the machine frame 3. After holding the rear end of the film 2 pulled out to the upper part in the machine frame 3, the rear gripper G
Are disposed on the rear side of the machine frame 3 in the direction facing the front gripper F so as to be horizontally movable.

Incidentally, the film drawn from the roll film held by the film supply device E is inserted between the film holding plates 61 and 62 and drawn horizontally toward the packaging section B. I have. The above-mentioned film holding plates 61 and 62 are formed in a comb-like shape at the leading edge, and are placed in a state of being overlapped immediately before the rear gripper G in a standby state, and the film 2 is inserted between the two plates 61 and 62. A gap is formed. Further, the film holding plates 61, 6
The length of the film 2 to be pulled out through the film 2 is set to a predetermined size according to the size of the product 1. The film pulled out by a predetermined length by the front gripper F is cut by a cutter disposed at the front end of the film holding plates 61 and 62 after the rear end is sandwiched by the rear gripper G.

The packaging section B includes left and right clamping devices H (see FIG. 3) for holding the left and right side edges of the film 2 on both sides of the machine frame 3 perpendicular to the film 2 drawing direction.
The four side edges of the film 2 pulled out from the film supply device E are sandwiched by the devices F, G, and H so that the film 2 is tensioned.

The front gripper F and the rear gripper G are provided with upper fixed clamp plates 7 and 8 and a lower movable clamp plate which is opened and closed with respect to the fixed clamp plates 7 and 8 by a cylinder (not shown). 9 and 10. The movable clamp plates 9 and 10 are respectively divided into three central clamp plates 9a and 10a and left and right clamp plates 9b and 10b, and the central clamp plates 9a and 10a and the left and right clamp plates 9b and 10b open and close independently. I do. The front gripper F and the rear gripper G are individually fixedly supported by timing belts 13 and 14 that rotate in the front-rear direction by unique motors 11 and 12 disposed on both sides of the machine frame 3, respectively. Advance by 11 and 12,
It moves backward (see FIG. 2). That is, the motor 11 and the timing belt 13 constitute a transfer mechanism P1 of the front gripper F, and the motor 12 and the timing belt 14 constitute a transfer mechanism P2 of the rear gripper G. Further, after the product 1 is upwardly supplied toward the film 2 by the carrier C, the front and rear ends of the film 2 and the left and right side edges are placed on the upper portion where the devices F, G, and H are disposed. Folding devices I and J are provided which are operated to fold toward the bottom.

The longitudinal folding device I includes a pair of front and rear folding write plate 15 across the width direction of the machine frame 3, as shown in FIG. 3, respectively before and after horizontally divided into a front gripper F side and the rear gripper G side It is movably arranged. The above-mentioned front and rear folding plates 15 are fixedly connected to both ends of the plate via connecting arms 18 to a drive chain 17 rotated by a motor 16, which is wound around both sides of the machine frame 3 in a front-rear direction,
The leading and trailing ends of the film 2 are simultaneously folded into the bottom side of the product 1 by bringing the distances closer to each other at the synchronized moving speed. Incidentally, either one of the front and rear folding write plate 15, a heater 19 for heat sealing the folded edges of the folded plate 15 previously in the illustrated example is embedded mounted (see FIG. 3).

Meanwhile, the left and right folding device J includes a pair of left turn right write plate 20 over between the two folding write plate 15 before and after waiting in the open state
And it is arranged freely horizontal motion in the lateral direction on the left and right sides of the machine frame 3 in a state of being positioned on the longitudinal folding write plate 15. The left and right folding device J has a guide bush 23 provided at the front and rear ends thereof slidably inserted along two rotating shafts 22 which are rotatably supported via a chain 17 and a sprocket 21 in an interlocking manner. The rear ends of the left and right folding plates 20 are fixed via a connecting arm 25 to a chain 24 disposed on the rear gripper G side. Then, the film 2 is moved closer to each other at the moving speed synchronized by the operation of the motor 26 and
Of the product 1 are simultaneously folded into the bottom side of the product 1.

The right and left clamping device H, an air cylinder 27 which is installed below the left and right folding write plate 20 to wait in an open state
The lifting frame 28 is connected to the upper end of the rod, and a movable clamp plate 29 having a substantially L-shaped cross section with respect to the lifting frame 28 is attached and supported via a guide pin 31 on which a spring 30 is elastically mounted. (Figure 13), are movably supported in the opening direction of movement of the left and right folding write plate 20. Then, by abutting the lower surface of the left turn right write plate 20 the movable clamp plate 29 is raised by the cylinder 27, has become as to sandwich the left and right side edges of the film 2.

By the way, below the right and left folded write plate 20 of the left and right folding device J that described above in machine frame 3 are disposed a pair of left and right spraying nozzles 80. The spray nozzle 80 pushes up the product 1 against the film 2 tensioned in the packaging part B, and when the left and right end portions of the film 2 are folded into the bottom surface of the product 1 by the left and right folding plates 20, the spray nozzle 80 faces the bottom surface of the product 1 By blowing compressed air toward the left and right ends of the film 2 hanging down from the activated left and right folding plates 20, the left and right ends of the film 2 are pushed deeply toward the bottom center of the product 1. . Left and right spray nozzles 8
No. 0 is connected to a compressed air supply source (not shown) via an air supply pipe 82, and a nozzle port 81 from which compressed air is blown out.
And the left and right folding plates 2 in a state where the film 1 is turned toward the center of the packaging portion B where the center of the bottom surface of the product 1 is located when the film 1 is folded.
It is mounted and supported below 0.

An electromagnetic valve (not shown) is provided inside the spray nozzle 80 or in the middle of the air supply pipe 82, and the opening / closing operation timing of the electromagnetic valve is controlled by a control unit (not shown). immediately after the right and left ends of the film 2 is folded in both the right and left folded write plate 20, compressed air of about 4~5kg / cm ² from both spray nozzle 80 is configured to be blown out for a predetermined time.

As shown in FIG. 14 (a), the two spray nozzles 80 are attached at an inclination angle of about 5 ° in a plan view, and blow out from the left and right nozzles 80. The blow-off flows thus merged at the center of the packaging section B via the above-mentioned inclination angle.
Further, the nozzle port 81 of the spray nozzle 80 has an inner diameter of, for example, about 1.2 mm, and has a horizontally long oblong shape as shown in FIG. The blowout flow is configured to spread horizontally to form an appropriate width in the lateral direction at the center of the packaging section B (FIG. 20). As shown in FIG. 28, the nozzle opening may be configured by arranging about three relatively small round holes in the horizontal direction. If three nozzle openings are arranged in a round hole as described above, the upper and lower portions are not sprayed much like the elliptical hole, so that the efficiency is high. However, the shape of the nozzle opening may be a round hole or each hole. The detailed operation of the spray nozzle 80 will be described later.

The transfer table C receives the commodity 1 placed on the carry-in section A and weighed, and at the same time, conveys the commodity 1 below the packaging section B. The film 2 pulled out from the packaging section B from below and stretched is stretched. The upright portion 32 is formed at an interval passing between the comb-shaped mounting rods 4 constituting the carry-in portion A to form a head base 33, and the head base 33 is provided. A receiving portion 34 for receiving the product 1 is fixed on each of the upright portions 32. The carriage C is supported by a drive mechanism D via a support member 35, and is moved horizontally and vertically into the machine frame 3 by the operation of the drive mechanism D.

Driving mechanism D installed at the lower part in machine frame 3
Is for moving the transfer table C from the loading section A to the packaging section B. As shown in FIG. 4, the transfer table C supported by the support member 35 is moved between the loading section A and the packaging section B. It comprises a horizontal operating unit D1 for moving the space horizontally, and a vertical operating unit D2 for moving the carrier C in the vertical direction at each of the loading unit A and the packaging unit B.

The support member 35 is provided with guide pillars 36 on both sides of the machine frame 3 erected with the lower end fixed, and supports both side frame portions between the both guide pillars 36 so as to be slidable up and down. A vertically movable frame 37 having a flat rectangular shape disposed horizontally inside the guide frame 38 and a guide groove 38 provided on the inner surface of each of the frames on both sides of the vertically movable frame 37 are fitted and latched on both sides thereof. And a front and rear moving plate 39 supported slidably in front and rear. And the above-mentioned front and rear moving plate 3
The head base 33 of the carriage C is mounted and supported on the support 9 via support legs 40 formed in an L-shape. According to this,
The support legs 40 allow the carrier C to enter under the loading portion A without making the length of the support rod 6 too long (FIG. 4).

The horizontal operation unit D1 includes a cam 44 mounted on an output shaft 43 of a speed reduction box 41 driven by the operation of a motor 42, and a cam 4
4 is provided with a swing arm 46 that swings up and down with the rear end pivot 45 as a fulcrum by the rotation of 4. Also, the horizontal operation unit D1
Form a substantially L-shaped arm main body, and
A starting arm 49 pivotally supported by a rotating shaft 47 erected at the bottom and connecting the swinging end of the swinging arm 46 to the short side end via a connecting arm 48; The longitudinal end of the activation arm 49 is fitted into a connection elongated hole 50 formed over substantially the entire length thereof, and is slidably movable along the elongated hole 50. And a vertical arm 51 connected thereto.

The horizontal operation section D1 is driven by a vertical movement of the swing arm 46 along the cam floor of the cam 44 which is rotated by the main motor 42. The transport table C is moved from the loading section A to the lower side of the packaging section B via the front and rear moving plate 39 by causing the longitudinal side to move in the longitudinal direction (FIGS. 5 and 6). B is moved from under B to under A.

On the other hand, the vertical operation part D2 is
And a swing arm 5 which is connected to the cam 52 and swings up and down around a rear end pivot 53.
4, the swing end of the swing arm 54 and the support member 34
And a connecting arm 55 having ends connected to the vertical moving frame 37. And the main motor 4
With the vertical swinging operation of the swinging end of the swinging arm 54 along the cam floor of the cam 52 rotated by 2, the transfer table C is moved via the vertical moving frame 37 at the positions of the loading section A and the packaging section B respectively. It is configured to move up and down. That is, in the loading section A, the state of FIG. 1 rises from the state of FIG. 1 to the state of FIG. 5, and in the packaging section B, it rises and falls as shown in FIG.

Next, the stretch packaging method of the present invention will be described based on the operation steps of the packaging machine configured as described above.
In the stretch wrapping machine, each device and each mechanism are sequentially operated at a predetermined timing by a sequence and a timer control by a control unit (not shown) including a microcomputer, and the packaging of the product 1 proceeds. Less than,
The packaging process will be described with reference to FIGS. First, an operator places the product 1 on the loading section A and turns on the operation switch of the apparatus. Then, the transport table C waiting under the loading section A first rises by the vertical operation section D2, and receives the product 1 from the loading section A (FIG. 5). At the same time,
The transport table C is moved below the packaging section B by the horizontal operation section D1 while maintaining its height, and transports the product 1 to a predetermined position below the packaging section B (FIG. 6).

In parallel with the transport operation of the product 1, as shown in FIG. 7, the leading edge of the film 2 held between the film holding plates 61 and 62 is clamped by the front gripper F to start the drawing operation. Then, the film 2 is pulled out in the direction of the packaging portion B by a length set according to the size of the product 1 (FIG. 8). At this time, the rear gripper G is attached to the film holding plate 6.
The front gripper F stands by at the rear side of the first and second films 62 and does not hinder the movement of the front gripper F holding the leading end of the film 2.

Next, the rear gripper G waiting on the rear side of the film holding plates 61 and 62 advances to the front of the cutter K, and holds the stretched film 2 (FIGS. 9 and 10). Also, during or before and after the centering operation of the cut film 2, the cut film 2 is stretched by a predetermined amount in the longitudinal direction by the gripper F and the rear gripper G, and pre-stretched.

Thereafter, the film 2 is cut by the cutter K after the rear gripper G (FIG. 11). As a result, the cut film 2 is in a state where the front and rear edges are sandwiched by the front and rear grippers G and F. After the film 2 is separated, the front gripper F and the rear rear gripper G move at a synchronized speed, and stop when the center of the film 2 sandwiched between the two grippers coincides with the center of the packaging portion B. (FIG. 12). With this, cut film 2
And the centering of the packaging part B is performed.

Thereafter, as shown in FIGS. 13 (a) and 13 (b), the left and right side edges of the film 2 are clamped by the right and left clamping devices H and the right and left folding devices J, and at the same time, as shown in FIG. By stretching the film 2 to the left and right, the film 2 pulled out to the packaging part B is prestretched and expanded, and the four side edges of the front end, the rear end, and the right and left side edges are held. On the other hand, as shown in FIG. 6, the transport table C moved below the packaging section B rises toward the film 2 expanded in the packaging section B by the operation of the vertical operation section D2. Supply product 1 to B.

When the carriage C reaches a predetermined height in the course of raising the product 1, the left and right folding plates 20 move slightly inward as shown in FIG. give. Immediately thereafter, the film 2 is pushed up from below by product 1 (FIG. 16), then at the time when the left turn right write plate 20 of the left and right folding device J is toward the folding direction to move to a predetermined position, supported by the air cylinder 27 The moved clamp plate 29 is separated from the left and right folding plates 20 to release the left and right side edges of the film 2.

Subsequently, the left and right folding plates 20 move toward the center and stop with a slight gap at the center of the bottom surface of the product 1 (FIG. 18). At this time, the left and right ends of the film 2 folded into the bottom surface of the product 1 by the left and right folding plates 20 are in a state of hanging down from between the two plates 20 (FIG. 19). At this time, the center clamp plates 9a, 10 of the front and rear grippers F, G
"a" grips the center of the end of the film 2, and the clamp plate 29 of the left and right clamping device H is open.

Next, the front and rear folding plates 15 of the front and rear folding device I start to move toward the center of the packaging portion. At about the same time, from the left and right spray nozzles 80 toward the center of the
A compressed air of about 5 kg / cm ² is blown. First, the blowing from the right blowing nozzle 80 is started (FIG. 20), and the blowing from the left blowing nozzle 80 is performed slightly after that (FIG. 21). More specifically, the spraying from the right spraying nozzle 80 is performed twice with an interval of about 0.12 seconds and 0.08 seconds, and further 0.08 seconds after the start of the operation of the right spraying nozzle 80. The spray from the left spray nozzle 80 is continuously performed for about 0.24 seconds.

As described above, the left and right spray nozzles 80
The right and left ends of the film 2 are alternately pushed on the bottom surface of the product 1 by alternately shifting the timing of spraying performed between them, so that the left and right end portions of the film 2 are pushed down onto the bottom surface of the product 1 without hanging down. Can be attached. Note that the spraying of the spray nozzle 80 may be alternately performed such that the left side is first and the right side is later.
Further, as described above, by inclining the direction of the nozzle openings 81 of the left and right spray nozzles 80 by about 5 °, the product 1
The interference of the blowing flows from the left and right blowing nozzles 80 that collide near the center of the bottom surface is reduced, and the left and right ends of the film 2 can be reliably folded.

Further, by widening the shape of the nozzle port 81 in the horizontal direction as described above, a wide blowout in the horizontal direction and a thin blowout flow in the vertical direction are formed along the bottom surface of the product 1, and the left and right ends of the film 2 are formed. The part can be pushed in effectively without waste. However, if a blowing flow that is wide enough to cover the entire width of the film 2 is sent, the film 2 gathers at the center and the seal length cannot be secured, so that the blowing flow does not reach the front and rear ends of the film 2. Is good. The above-mentioned spraying of the left and right spraying nozzles 80 ends when the folding operation of the front and rear folding plates 15 has advanced about half.

[0042] Subsequently, the progresses fold actuated by longitudinal folding write plate 15, two handles F before and after in a manner that Tsuido this, G
There moved toward each other, the front and rear ends of the film 2 already left and right ends of the film 2 is folded equally toward the center of the bottom of the product 1 to be attached, by abutting the folding edges of the front and rear folding write plate 15 Heat sealing is performed (Fig. 23-
a, b and FIG. 24).

Thereafter, the front, rear, left and right folding plates 15 and 20 are retracted, and the product 1 is removed from the packaging portion B (FIG. 2).
5). The film 2 which is tension-coated on the product 1 is folded back and forth equally on the bottom surface side of the product 1 and is adhered to the center of the bottom of the product 1 via a folding margin of the same size in the front and rear. Then, attach the end of the film 2 to the bottom of the product 1
Packaging with a wide adhesive surface as shown in 6 is completed.

The above-described stretch wrapping machine, right and left by spraying both blowing compressed air from the nozzle 80, further the left and right ends of the tucked in the left and right folding plates 20 to be activated first to the bottom surface of the product 1 Film 2 The film is pushed toward the center of the bottom surface, and in this state, the front and rear folding plates 15 which operate later are used to wrap the front and rear ends of the film 2 in a packaging method. Therefore, when the front and rear end portions of the film 2 are folded, they overlap with the left and right end portions of the film 2 pushed toward the center of the bottom surface of the product 1 by blowing compressed air through a large area, and FIG. Can be obtained as a product 1 shown in FIG. still,
Even if the spraying from the left and right spray nozzles 20 is performed simultaneously, the effect of increasing the depth of folding at the left and right ends of the film 2 can be sufficiently obtained.

Further, in the above embodiment, the blowing from the both blowing nozzles 80 was performed after the folding operation of both the left and right folding plates 20. However, during the folding of the left and right folding plates 20, both the left and right clamping devices H are used for the film 2 This may be performed when the left and right ends are separated. In this case, since the left and right end portions of the film 2 move to the center of the bottom surface of the product 1 before the left and right folding plates 20, the folding can be performed smoothly without being caught by the left and right folding plates 20. Can be.

FIG. 27 shows that both right and left blowing nozzles 280 are provided along the inside of both left and right folding plates 20. Pipe-shaped blowing nozzles 280 are introduced from one end of both left and right folding plates 20 toward the center. A nozzle opening 281 is opened at the center of the folding edge of the left and right folding plates 2. According to the provision of the two spray nozzles 280 on the left and right folding plates 20 as described above, the nozzle port 2 is moved with the movement of the left and right folding plates 20.
Since the spraying position from 81 moves and the spraying can be performed from a position near the end of the film 2 at the time of folding, a sufficient pushing force can be obtained even if the pressure of the compressed air is low, and Since the position of the blow to the nozzle becomes accurate, it is possible to relatively freely set the insertion fold.

According to the gist of the present invention, the two spray nozzles need to be provided at the lower part of the folding plate which is operated to be folded. In the above embodiment, even if the film end is not folded deeply to the center of the bottom surface of the packaged object by the folding plate which is operated first, the squeezing is sprayed on the film end together with the folding, so that the film end folded first. Is kept pressed down to the center of the bottom of the package, and can be overlapped over a large area with the edge of the film to be folded later.This increases the width of adhesion between the edges of the film and facilitates heat sealing. In addition, packaging that is difficult to peel off can be performed.

In the above embodiment, since the packaging is completed by folding and heat sealing with the front and rear folding plates 15, the spray nozzles 80 are provided below the left and right folding plates 20. For example, in the case where the left and right folding plates 20 are folded later to perform heat sealing, the spray nozzle may be disposed below the front and rear folding plates 15. Further, the present invention can be applied to a type in which the product 1 is automatically discharged from the packaging section B or a type in which the end of the film is heat-sealed with the surface at the bottom of the product. A spreading effect can be obtained. And regardless of the order of the insertion direction,
Blowing air between the film ends is effective even if the films are merely bonded by wind pressure.

[0049]

As described above, in the stretch packaging method of the present invention, the folding direction of the packaging film to be folded is not deeply folded, and only the central portion of the folded side of the film is folded . Blowing almost simultaneously with operation
Since it is intended to perform folding of the write Nde film sides pressed on the bottom center of the packaged articles by blowing the air to start with can, as compared with the conventional method, the longitudinal direction and lateral direction of the film edge in the folding state The overlapping area between the parts is increased, and the bonding width can be greatly increased. As a result, adhesion by heat sealing becomes good,
It is possible to reliably package the film so that the film does not peel off after the packaging.

Further, the protrusion of the film end formed after the folding is reduced, and the finish of the folded portion is improved. Furthermore, even if water adheres to the packaged item such as vegetables, water does not leak from the folded portions other than the heat seal portion. Since the adhesive area between the film ends is large, even a polyethylene film having low adhesiveness can be used without any problem.

In the case where the blowing means is provided on the folding plate itself, the blowing position of the compressed air by the blowing means moves with the movement of the folding plate, and the blowing can be performed from a position close to the end of the film. The pressure of compressed air required for spraying can be reduced. Further, since compressed air is blown out from a place close to the film, the form of the film folding white can be more freely adjusted. Further, by blowing compressed air simultaneously with the operation of the folding plate, the folding resistance of the film can be reduced.

In the case where the blowing operation of the pair of blowing means is performed alternately between front and rear or between left and right,
Since the film ends folded first adhere to the bottom surface, the film ends folded by the folding plate operated later come to be folded in a state of being in direct contact with each other,
This makes it possible to directly heat-seal the film ends to be folded later, thereby increasing the adhesive strength.

[Brief description of the drawings]

FIG. 1 is a side view showing a stretch packaging machine embodying the present invention.

FIG. 2 is a perspective view showing both front and rear grippers in a packaging unit.

FIG. 3 is a perspective view showing a main part of a front / rear / left / right folding device in a packaging unit.

FIG. 4 is a perspective view of a main part showing a transfer table and a drive mechanism thereof.

FIG. 5 is a schematic diagram showing a state in which the transfer table has received an object to be transferred from a loading unit.

FIG. 6 is a schematic diagram showing a state in which a carrier on which an article to be packaged is placed is moved to a position below a packaging unit.

FIG. 7 is a schematic diagram showing a film tip held by a film holding plate portion.

FIG. 8 is a schematic view showing a state in which a film is pulled out.

FIG. 9 is a schematic diagram showing a state in which a rear gripper has been moved to a position in front of a cutter;

FIG. 10 is a schematic diagram showing a state in which a film is held by a rear gripper.

FIG. 11 is a schematic view showing a state where a film is cut by a cutter.

FIG. 12 is a schematic diagram showing a state in which a film sandwiched by both front and rear grippers is centered with respect to a packaging unit.

FIG. 13 is a schematic view showing a left and right folding device in a state where left and right side edges of a film are sandwiched, where (a) is a plan view and (b)
Is a vertical sectional front view.

FIG. 14 is a schematic view showing a left and right folding device showing a state in which the film is tensioned to the left and right, (a) is a plan view,
(B) is a longitudinal front view.

FIG. 15 is a schematic diagram of a packaging unit showing a process of lifting the transfer table.

FIG. 16 is a schematic diagram of a packaging unit showing a state where a film is pushed up by a product.

FIG. 17 is a schematic diagram of a packaging unit showing a state where both left and right sides of a film are released.

FIG. 18 is a schematic diagram of a packaging unit showing a state where the left and right folding devices are closed.

FIG. 19 is a perspective view of a state in which the left and right folding plates are operated, as viewed from below.

FIG. 20 is a perspective view of a state in which spraying is started from a right spray nozzle, as viewed from the lower portions of the left and right folding plates.

FIG. 21 is a perspective view of a state in which spraying is performed from both left and right spray nozzles, as viewed from the lower portions of the left and right folding plates.

FIG. 22 is a perspective view of a state in which spraying is performed from a left spray nozzle when viewed from a lower portion of the left and right folding plates.

FIGS. 23A and 23B are schematic diagrams showing the front and rear folding device in a state where the front and rear folding plates are operated, wherein FIG. 23A is a plan view and FIG.

FIG. 24 is a perspective view of a state in which the front and rear folding plates are operated, as viewed from below.

FIG. 25 is a schematic diagram of a packaging unit showing a state in which a product is picked up.

FIG. 26 is a bottom view of the product.

FIG. 27 is a plan view showing a packaging unit of a packaging machine in which spray nozzles are provided on left and right folding plates.

FIG. 28 is a front view showing a spray nozzle having three small nozzle holes arranged in parallel.

FIG. 29 is a perspective view of a state in which left and right folding plates are operated in a conventional stretch packaging machine, viewed from below.

FIG. 30 is a perspective view of the state in which the front and rear folding plates are operated in the conventional stretch packaging machine as viewed from below.

FIG. 31 is a bottom view showing a product packaged by a conventional packaging method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Merchandise (object to be packaged) 2 ... Film 15 ... Front and rear folding plate 20 ... Left and right folding plate 80 ... Spray nozzle 81 ... Nozzle port B ... Packaging part

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-239412 (JP, A) JP-A-4-339717 (JP, A) JP-A-6-345015 (JP, A) JP-A-56- 57610 (JP, A) JP-A-3-176322 (JP, A) JP-A-1-141203 (JP, U)

Claims (4)

(57) [Claims] 1. A packaging film is tensioned, an object to be packaged is pushed up against the packaging film to cover the surface, and sides of the packaging film in the front-rear direction and the left-right direction are formed by a left-right folding plate and a front-rear folding plate. folding toward the center of the bottom of the packed material, the stretch wrapping method for heat-sealing the overlapping film, the right and left direction or the direction of folding of folding to any preceding longitudinal direction, its
Side in the direction perpendicular to the pair of film sides to be folded
Part only at the center of the film width and the left and right sides
Open and fold the corresponding pair of film sides with a pair of folding plates so that they do not become deeper, and fold it by a predetermined amount.
The pair of the film sides that written, the blows pair of compressed air facing only to a substantially central portion of the pair of film sides folded to operate substantially simultaneously folding <br/> write plate after A stretch packaging method characterized by being pushed into the center of the bottom of a package. 2. An object to be packaged is lifted and pushed up with respect to the packaging film tensioned at the packaging section, and the front and rear folding plates and the left and right folding plates are folded by the side portions of the packaging film in the longitudinal and lateral directions. Is folded toward the center of the bottom surface of the packaged object, and the front and rear sides of the packaging film
Before and after gripping the left and right sides of the gripper or packaging film
Folding operation first of the left and right clamp devices that clamp both side edges
Before sandwiching the film edge in the direction perpendicular to the folding plate
・ Rear side gripper or left and right clamping device in center of width direction
In the form of a plurality of divisions including a part, the front and rear folding plate or the left and right folding plate is operated to fold either end, below a pair of folding plates that stop with a slight gap at the bottom center of the packaged object,
Its folding plate Ri name by arranging a pair of spray means facing blowing compressed air toward only the substantially central portion of the pair of film sides to be folded by the folding operation, folding previously
The side in the direction orthogonal to the pair of film sides
Hold only the center of the film width and open the left and right sides.
In the state, the blow-in
Stretch wrapping machine characterized by spraying by wiping means . 3. The stretch packaging machine according to claim 2, wherein said spraying means is provided on the folding plate itself. 4. The stretch packaging machine according to claim 2, wherein the spraying operation of the pair of spraying means is performed substantially alternately between front and rear or between left and right.