JPH08217008A - Method for wrapping article with stretch film and stretch wrapping machine - Google Patents

Abstract

PURPOSE: To reduce the size, weight, and cost of a device without sacrificing the basic performance of a conventional wrapping machine, by using a narrow stretch film compared to a conventional one, and by uniformly stretching it widthwise, thereby wrapping an article, ranging from the smallest to largest size, with the same film. CONSTITUTION: The both sides of the front end of the film 4' of a film roll 4 are sandwiched and held by a film-holding means B. When an article G to be wrapped is carried and placed on an elevator, a film feed means is actuated to sandwich the film 4' and pull it out a specified length, and it cuts the film with a cutter, also sandwiches the sides of the cut film 4a over its full length, and positions the center of the film 4a onto the center of a wrapping part. Then, by the actuation of a distance increase means, a feed means C2 on a movable side uniformly increases the width of the film, matching the size of the article, over its full length. Subsequently the article G is pushed up by the elevator and wrapped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of wrapping an article with a stretch film and a stretch wrapping machine, and more particularly, a stretched film (hereinafter referred to as a film) stretched around a wrapping portion is used to push an article to be wrapped from below. The present invention relates to a so-called elevator type packaging method and a packaging machine in which an upper surface of an article to be packaged is covered with a film and then an end portion of the film is folded into a bottom portion of the article to be packaged.

[0002]

2. Description of the Related Art At present, this type of packaging machine is widely used for packaging fresh foods, bento boxes, etc. sold in supermarkets, convenience stores and the like.
Various types have been developed. Conventionally, the requirements for this type of packaging machine have been mainly those relating to basic performance such as high speed, easy handling, and a wide range of sizes of products that can be packaged, and satisfy such requirements. As a packaging machine, for example, JP-A-50-1631
No. 12 and Japanese Patent Laid-Open No. 4-339709. These packaging machines are about 30 per minute
In addition to having the processing capacity of the pack, it can detect the size of the product and automatically determine the film type and film length to be used, or the adjustment data for control, making it extremely easy to handle. ing. Also, by equipping two kinds of films with different film widths, and automatically switching the film to be used according to the size of the product, the product of a very wide range of sizes looks good and economically (the film is wasted. It can be packaged (without).

[0003]

However, recently, in addition to the basic performance described above, there has been a strong demand for reduction in size and weight of the device and cost reduction. The packaging machine described above is as follows. Have some problems. That is, it is necessary to provide an automatic film switching mechanism in order to equip two kinds of films having different film widths and automatically select and use one of the films depending on the size of the packaged object. Since the automatic switching mechanism has a complicated structure, the size of the entire device is increased, which is a major obstacle to downsizing and weight reduction of the device and cost reduction.

The present invention has been made in view of the problems of the above-mentioned conventional technique, and the purpose thereof is to:
(EN) Provided are a packaging method and a packaging machine that can package a minimum size to a maximum size of an object to be packaged with the same film without sacrificing the basic performance of a conventional packaging machine, and can achieve reduction in size and weight and cost. Especially.

[0005]

In order to achieve the above-mentioned object, the packaging method according to the present invention is such that the article to be packaged is pushed up from the lower side to the film stretched on the upper side so that the upper surface of the article to be packaged is a film. In the packaging method that folds the edge of the film to the lower side of the object to be wrapped after covering, a stretch that is one rank narrower than the one used when wrapping the largest size object to be wrapped conventionally as the film to be used. Using a film, including the step of uniformly expanding the film in the width direction before pushing up the packaged object, the same size of the minimum to the maximum size of the packaged object, and the conventional maximum size of the packaged object. It is characterized in that it is wrapped with a film which is one rank narrower than the film used for packaging. Examples of the stretch film used include vinyl chloride film. The expansion of the film may be completed before the object to be packaged is pushed up.Therefore, the method is to convey the film to the packaging position and then expand it before the product is pushed up, or convey the cut film to the packaging position. There is a method of expanding in the process of doing. The amount of expansion of the film in the width direction before pushing up the packaged object is changed according to the size of the packaged object.

A packaging machine for carrying out the above-described packaging method pushes up the article to be packaged from the lower side to the film stretched on the upper side to cover the upper surface of the article to be packaged with the film, and then the end of the film is packaged. In a stretch wrapping machine that folds downward, a film feed unit that conveys a film cut to a predetermined length by sandwiching both widthwise end portions of the film to a wrapping position, and a widthwise interval of the film feed unit. And a space expanding means for expanding the film, and before the product is pushed up after the film has been conveyed to the packaging position, the space expanding means expands the space in the width direction of the film feeding means to extend the width of the film over the entire length of the film. It is characterized by expanding uniformly. The interval expanding means for expanding the widthwise interval of the film feeding means fixes the film feeding means for holding one of the side edges of the film,
The film feed means for holding the other side of the film may be movable, or both the left and right film feed means may be movable.

Further, the packaging machine for carrying out the method of expanding the film in the process of transporting it to the packaging position is provided with a film feeding means for transporting the film to the packaging position, and a space expanding means for expanding the space between the film feeding means in the width direction. And in the process of transporting the cut film to the packaging position,
The width of the film is uniformly expanded over the entire length of the film by operating the interval expanding means to expand the width of the film feeding means in the width direction.

Further, another wrapping machine for carrying out the method of expanding the film in the process of transporting it to the wrapping position holds the both side edges of the film in the width direction and pulls out the film,
It has a film feed means for conveying the film cut into a predetermined length to the packaging position, and the distance between the left and right film sandwiching portions of the film feed means is such that the film supplied from the film roll is conveyed to the packaging position. The width of the film is sequentially expanded in the width direction, and the width of the film is uniformly expanded over the entire length of the film when the film is conveyed to the packaging position. The film feeding means is constructed by attaching an upper and lower grips for sandwiching the end portion of the film to an endless member such as a chain or a belt which is installed so as to be gradually widened from the film supply portion to the packaging position.

Another packaging machine for carrying out the above method is
After pulling out the film while sandwiching both side ends in the width direction of the film, a film feed means for conveying the film cut to a predetermined length to a packaging position, a film supply unit in which a film roll is arranged, and the film. A film width expanding unit that is arranged between the feeding unit and the film supplying unit and sequentially expands the film supplied from the film roll in the width direction and then transfers the film to the film feeding unit, and wraps the film by the film feeding unit. The film is characterized in that the width of the film is uniformly expanded over the entire length of the film when it is conveyed to the position. The film width expanding means is composed of an endless member such as a chain or a belt arranged in a substantially C-shape in plan view, and an upper and lower grip for holding the end portion of the film is attached to the endless member. The film feed means for receiving the expanded film and conveying it to the packaging position is constructed by vertically arranging belt conveyors.

[0010]

According to the above means, the film is uniformly expanded in the width direction before the object to be packaged is pushed up, and the object to be packaged is wrapped with the expanded film, whereby the film width conventionally used. It is possible to wrap a maximum size object to be packaged with a film that is narrower than the rank by one. And in the packaging machine that implements the above method,
Since the film feeding means is moved in the width direction by the space expanding means and expanded until the article to be packaged is pushed up, the entire length of the film cut to a predetermined length can be uniformly expanded, and the minimum size to the maximum size can be expanded. It becomes possible to wrap an article to be packaged with the same film. Moreover, since the film feeding means is expanded by the space expanding means, it is possible to easily change the amount of bristle stretch according to the size of the article to be packaged.

Further, in the packaging machine for pre-stretching in the process of conveying the film to the packaging position, the processing speed of the packaging can be improved, and the number of members to be moved in the width direction for pre-stretching is small. Since it is good, the device can be downsized.

Even in the conventional apparatus, the film is expanded in the width direction before the object to be packaged is pushed up from below, which is known as so-called pre-stretch. For example, the above-mentioned packaging machine also performs pre-stretching with a side clamp. However, the conventional pre-stretch is intended to make the film of the package free of wrinkles, and the amount of pre-stretch and its meaning are completely different. This is also clear from the fact that each of the above packaging machines has an automatic film switching mechanism.

Another example of the pre-stretch is US
P. Although there is 3967433, in this case as well, it is a structure for protecting the upper surface of the package and is essentially different from the present invention. Further, in the conventional packaging machines having a pre-stretch mechanism, after clamping the front end of the film and pulling out a predetermined amount (length) of the film, the both side ends in the width direction of the film are clamped by a pair of clamp members. Then, the clamp members are moved in a direction in which they are separated from each other, thereby pre-stretching the film in the width direction.

However, with such a structure, the portions sandwiched by the clamp members at both end portions of the film are a part of the central portion in the length direction, and are not sandwiched over the entire length of the film. Pre-stretching in the width direction cannot be performed uniformly over the entire length of the film. In addition, the length of the film changes depending on the size of the product to be packaged (object to be packaged), and the ratio of the sandwiched portion to the entire length of the side end portion changes depending on the length of the film to be drawn and cut. Will not be performed uniformly. Such problems are
When the amount of pre-stretch is relatively small, it does not have such a large effect, but when the amount of pre-stretch is increased and a wide range of products of different sizes are packaged using a single film width film roll. Will affect the packaging finish. Further, in the conventional packaging machine, since the pair of clamp members are arranged at positions corresponding to both widthwise end portions of the film for pre-stretching, the configuration of the packaging machine is complicated.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, the method for wrapping with a stretch film according to the present invention, the stretch film stretched over the wrapping portion, the article to be packaged is pushed up from below to cover the upper surface of the article to be packaged with the film, and then the end of the film is In a so-called elevator type packaging method in which the stretched film is folded into the bottom of the article to be packaged, a stretch film having one or more ranks narrower than that used in the case of packaging a maximum size object to be packaged is used as a film to be used. Then, it comprises a step of uniformly expanding the film in the width direction before pushing up the object to be packaged, and for the object to be packaged of a size which cannot be conventionally packaged with the film width of the used film, the width of the film is It is expanded to the same extent as the film width of the film used when packaging an object to be packaged of this size. Then, the expanded film is used for packaging. As a result, the same size film from the smallest size to the largest size to be packaged, and a film that is one rank narrower than the film used to package the largest size package in the past. Is to be packaged in. The minimum size,
The maximum size of the packaged object means the minimum and maximum size of the packaged object to be packaged by each user within the range of the minimum size and the maximum size of the packaged object that can be packaged by the packaging machine.

Further, the width of one rank or more means that the type of film generally used conventionally is, for example, 250 m.
m, 300 mm, ... 550 mm, 600 mm are manufactured at regular intervals (50 mm intervals in the above example), and for a certain film, for example, 500 mm film, one interval narrow, that is, 450 mm film is one rank A film having a narrow width and a narrow spacing, that is, a film having a width of 400 mm is expressed as a narrow width of two ranks. Further, the film to be used may be any film as long as it can achieve the object of the present invention, and is not limited. Stretch film is suitable.

Further, the means for expanding the film in the width direction, that is, the expansion amount (maximum expansion amount) in the case of packaging the maximum size object to be packaged, is the type of film to be used and the range of the object to be packaged (minimum size, Maximum size), but generally the following can be said. Maximum 200% for vinyl chloride and polyethylene films mentioned above
The film can be expanded to a certain extent, and the larger the expansion amount is, the more the effect of saving the amount of use of the film can be obtained. However, when the expansion amount is large, the film becomes thin and the uniformity is deteriorated.
Further, particularly in the case of a polyethylene-based film, since the elasticity is strong and the force for shrinking becomes large, problems such as deformation of the object to be packaged occur, so an upper limit of about 100% is appropriate. Also, if the expansion amount is small, the effect of saving the used amount of the film is reduced, so the lower limit may be about 30%. However, if the expansion amount is too small, the film is wasted when the minimum size object is packaged. Since the number of sheets increases and the appearance of the packaging becomes worse with an extra film, it is preferable to expand by 50% or more in consideration of this point. That is, when the above film is used, the maximum expansion amount is in the range of 30% to 100%, more preferably 50% to 1
A range of 00% is suitable.

In the above method, the expansion of the film may be completed at least before the object to be packaged is pushed up. Before the object to be packaged is pushed up, the film cut into a predetermined length is conveyed to the packaging position. It may be either until the article to be packaged is pushed up by the method described above, or while it is pulled out from the film roll, cut into a predetermined length, and then conveyed to the packaging position. The amount of expansion of the film in the width direction before the film is pushed up can be automatically or manually changed according to the size of the film.

A method of determining the expansion amount according to the size of the packaged object will be described. Since the packaged object supplied to the wrapping unit is placed on a tray and sent, the process until the tray is sent to the elevator apparatus. Detect the "depth" and "height" of the tray with a sensor, etc.
The "depth dimension (L)" and the "height dimension (H)" are added, and the value (A) is used to selectively determine the expansion amount of the film from the "expansion film width determination table". This "extended film width determination table" is created in the RAM in advance. An example of the "extended film width determination table" is shown in Tables 1 and 2 below for two types (250mm, 350mm) of different film widths used.

[0020]

[Table 1]
(Unit: mm)

[0021]

[Table 2]
(Unit: mm)

As described above, the expansion amount of each film can be switched in two stages or three stages according to the tray size. The minimum size of the target tray is the tray for tarako (130 width x 80 depth x 10 height, that is, L + H).
= 90), this can accommodate a 250 mm wide film by 40% expansion or a 350 mm wide film by 0% expansion. The maximum size is a jumbo tray (350 width x 250 depth x 20 height, or L + H = 270), which is 35
The film with 0 mm width can be expanded by 71%.

It should be noted that two types of films having different widths can be used because the products to be packaged by users vary, and not all users package products with L + H of 200 mm or more. This is because, for a user who packages only products of 200 mm or less, the film of 350 mm width can be wrapped, but the film is wastefully used, and the cost is increased accordingly. Therefore, 25 such users
It enables the use of 0 mm wide film. According to the invention of the present application, when a film having a width of 250 mm is used, L + H = 90 mm (minimum size)
+ H = 200mm (maximum size) products can be wrapped with one kind of film, and with a film that is one rank narrower than the film width (400mm) that was required when conventional maximum size products were packaged. It will be possible.

When a film with a width of 350 mm is used, one type of film, from the product of L + H = 90 mm (minimum size) to the product of L + H = 275 mm (maximum size), and the conventional maximum size It is possible to wrap a product with a film that is one rank narrower than the film width (500 mm) required for wrapping the product. still,
Needless to say, the number of usable films may be three or more. Although some users have L + H of 200 mm or more as a product to be packaged, it is very limited, and normally 250 if the packaging quantity is small.
By using a film with a width of mm, the operator can replace the film with a width of 350 mm with a film with a width of 350 mm only when packaging a product having L + H of 200 mm or more.

Next, a packaging machine for carrying out the above-described packaging method will be described. This packaging machine is controlled by a built-in CPU. The stretch wrapping machine shown in FIG. 1 and FIG. 2 is provided with a product placing portion a for placing an article to be packaged on a side of a machine frame A, and the article to be packaged placed on the article placing part a is conveyed by a conveyor F. It is transported to the elevator 1 provided inside the machine frame A. A packaging portion b is provided above the elevator 1, and a film roll arranging portion 2 and a leading end portion of a film 4'unrolled from the film roll 4 set in the arranging portion 2 are held on the side of the packaging portion b. The film holding means B is provided, and the film feeding means C for sandwiching and pulling out the film held by the film holding means B and conveying it to the packaging section b is arranged close to the tip of the film holding means B. Further, between the film holding means B and the film feeding means C, a cutter D for cutting the film held by the film feeding means into a predetermined length is arranged.

The film holding means B holds and holds both side portions of the film roll 4 set in the film roll arrangement portion 2, and as shown in FIG. 3, the endless belt 5 arranged below the film. And a pressing member 6 that presses the film supported on the surface of the endless belt 5 toward the endless belt 5, and the holding means composed of the endless belt 5 and the pressing member 6 has an interval corresponding to the interval of the film width. The pressing member 6 is provided at the front and rear, and one end of which is pivotally supported so that it can be opened and closed. The endless belt 5 is configured to be driven and rotated by a motor. Incidentally, the film holding means B may be constructed so that one or both of the holding means can be moved in the width direction according to the film width so as to correspond to the film roll set in the film roll arranging section 2.

The film feeding means C comprises a pair of upper and lower endless elastic belts 7 and 7'for sandwiching the side end portions of the film.
And a pressing belt 8 arranged on the upper surface of the lower elastic belt 7'on the starting end side so as to be overlapped with each other. The distance is the same as that of the pair of front and rear holding means. The pair of front and rear components are supported by the mounting frames 9 and 9 ', and the two mounting frames 9 and 9'are arranged below the mounting frames 9 and 9'and intersect each other at a right angle. The mounting frame 9 ', which is supported by the rods 10 and 10' through a connecting member 11, has one feed means C1 attached to it, and the other feed means C2 has an attachment frame 9 to which the guide frames 10 and 10 'are attached. 'Is configured to be freely movable, and the movable side feed means C2 is connected to a space expanding means E as shown in FIG. 4 so that the space between the movable side feed means C2 and the fixed side feed means C1 can be adjusted widely. Has been done.

The pair of upper and lower endless elastic belts 7 and 7'constituting the above-mentioned feeding means are driven and rotated in the same direction so that the film can be sandwiched and conveyed, and the driving method is a motor 12 with a speed reducer. Side sprocket 7'rotates the drive roller around which it is wound, and the chain sprocket is fixed to the shaft of the drive roller, and chain sprocket is fixed to the shaft of the drive roller around which the upper elastic belt 7 is wound. The power is transmitted by winding the chain over and the upper elastic belt 7 is also rotated. still,
The upper and lower elastic belts are equipped with a tension adjusting mechanism on the way so that the film can be sandwiched and conveyed stably and reliably.

The space expanding means E for moving the movable feeding means C2 of the film feeding means C in the width direction of the film is provided below the above-mentioned guide rods 10 and 10 'and is arranged at right angles to each other. The timing belts 13 and 13 'are wound around the rotary shaft 23, and the connecting members 11 fixed to the mounting frame 9 are provided on the upper portions of the timing belts 13 and 13'.
11 'are connected, and one of the rotating shafts is rotated in the forward and reverse directions via the motor 14 and the power transmission mechanism 15 to move the timing belts 13 and 13', thereby being connected to the timing belts. The movable feeding means C2 is moved in the width direction of the film. Then, the operation of the interval expanding means E determines the corresponding expansion film width from the above-mentioned "expansion film width determination table" according to the value obtained by detecting the size of the packaged object to be packaged, and accordingly the above The operation of the distance expanding means E is controlled.
Further, the operation of the interval expanding means E described above may be configured to be performed after the cut film is conveyed to the packaging unit and before the object to be packaged is pushed up, or the cut film is conveyed to the packaging unit. It may be configured to operate simultaneously in the process.

Next, the expansion operation of the film in the above packaging machine will be described with reference to FIG. 5. The both sides of the leading end of the film 4'of the film roll 4 set in the film roll arranging portion 2 are nipped and held by the film holding means B. At the same time, the leading end of the film 4'is held between the lower elastic belt 7'on the inlet side of the film feeding means C and the pressing belt 8 which are arranged close to each other. (See a in FIG. 5) When the object to be packaged G is conveyed and placed on the elevator 1, the film feeding means C is operated to hold the film 4'and pull out the film 4'by a predetermined length. The cutter D is actuated when the film is pulled out and cuts the film 4 ', and sandwiches the side part of the film 4a cut into a predetermined length over the entire length, and the center of the film 4a is the center of the packaging part b. Centering is performed so as to be located at.
When the centering is completed, the movable feeding means C2 of the film feeding means C is moved in the direction of expanding the film width by the operation of the space expanding means E, whereby the entire length of the film is packed. The film is uniformly expanded to the film width suitable for the size, and is held in the expanded state to wait for the object to be packaged G to be pushed up by the elevator 1. (See c in FIG. 5)

FIG. 6 shows the film expanding operation of the packaging machine configured such that the operation of the space expanding means E for expanding the film feeding means C in the width direction is performed at the same time as the film feeding by the film feeding means C. The operation (FIG. 6 (a)) of holding the film feeding means C between the holding means B and holding both sides of the film front end is the same as that of the embodiment shown in FIG. 5 (a), but the film feeding means C is fixed. The side film feeding means C1 and the movable side feeding means C2 hold the side end portions of the film and draw out a predetermined length, and the movable side feeding means C2 pulls out the film and operates the interval expanding means to change the width of the film. Move in the direction of expansion. (See b of FIG. 6) Then, the film is pulled out by a predetermined length and cut, and when the film is completely conveyed to the packaging unit, the centering of the film and the expansion to a predetermined width are completed. (See c in FIG. 6) In the packaging machine described above, the film is expanded by fixing one film feed means C1 and moving only the other film feed means C2, but both film feed means C1 and C2 are used. Of course, it is also possible to move.

In the above-mentioned packaging machine, the film pulled out by the film feeding means is completely conveyed to the packaging section,
Alternatively, the interval expanding means is simultaneously actuated to expand the film width during the conveying process, and the film feeding means is configured to move in parallel by the interval expanding means. FIG. 7 shows another example of the expanding operation of the film feeding means, in which the film feeding means C'has the same film receiving side as the distance of the film holding means,
The terminal end side of the film feeding means is opened in a divergent shape to be arranged in a substantially H-shaped plane, and the terminal end side is pivotally supported so as to be openable and closable. As a result, the leading end of the film is clamped from the film holding means, the film is expanded while being sequentially drawn out by the operation of the elastic belt that constitutes the film feeding means, and when the drawing is completed for a predetermined length, the film is cut, and the film feeding means is After completion of transportation, the film can be uniformly expanded over its entire length by expanding the starting end side outward with the shaft support side as the center.

FIG. 8 shows another embodiment of the wrapping machine for expanding the film 4'to a predetermined film width in the process of conveying the film 4'to the wrapping position by the film feeding means. The width of the film is gradually expanded in the width direction from the side of the means B to the side of the wrapping position, and when the film is transported to the wrapping position, the width of the film is uniformly expanded and held over the entire length thereof. Install in parallel with the space extended. The film feeding means C receives and clamps the leading edge of the film from the film holding means B, and the clamping portion 20 on the starting end side is composed of a pair of upper and lower elastic belts 16 and 16 'and a pressing belt 17 as in the previous embodiment. After that, the film sandwiching portion 19 consisting of a pair of upper and lower grips 19a and 19b is attached to the moving member 18 such as an endless chain or belt at a predetermined interval, and the moving member 18 moves from the starting end side to the packaging position. It expands sequentially in the width direction toward the carrying direction, and after reaching a predetermined expanded width, the width is maintained as it is in parallel. That is, the portions sandwiching the wrapping portion are held with a predetermined expansion width. Then, the pair of upper and lower grips 19a, 19b attached to the moving member closes the outward path from the starting end side to the packaging position as shown in FIG. 9 to sandwich the film, and after the packaging work is finished, it is used for the next packaging. As shown in Fig. 10, the upper and lower grips 19a and 19b are opened and the next film is moved so that the next film can be sandwiched. Further, the mechanism for opening and closing the pair of upper and lower grips for sandwiching the film is performed by a cam or the like attached along the moving member. still,
The opening / closing control of the grip may utilize the opening / closing mechanism disclosed in Japanese Utility Model Publication No. 1-20246 previously proposed by the present applicant.

The expanding operation of the film in the above-mentioned packaging machine will be described with reference to FIG. 11. The pinching portion 20 formed by the elastic belt on the leading end side of the film feeding means C is used to hold the leading end of the film 4'held by the film holding means. Then, both sides of the film are clamped, and the film is sequentially drawn out by the operation of the elastic belt, and is also transferred to the film clamps 19 of the upper and lower grips 19a and 19b attached to the moving member 18 and sequentially conveyed in the width direction. Extended to.
(See a in FIG. 11) Then, the film is pulled out by a predetermined length and cut, and when the cut film 4a is conveyed and reaches the packaging position, at that stage, the entire length of the film is uniformly expanded and centering is also performed. It is completed and waits for the object to be packaged to be pushed up. (See b in Figure 11)

FIG. 12 shows a wrapping machine provided with another expanding means for expanding the film to a predetermined width in the process of transporting the film from the film supply section to the wrapping position, and the expanding mechanism is a film holding means for holding the leading edge of the film. B, a film feed means C for conveying the film cut to a predetermined length to the packaging position b, and a film expanding means H arranged between the film holding means B and the film feed means C. The film expanding means H receives the film 4'supplied from the film holding means B, expands it to a predetermined width in the process of conveying it toward the film feed means C side, and the expanded film is fed to the film feed means C. It is configured to deliver. In the expanding mechanism, the film holding means B and the film feeding means C have the same structure as the embodiment shown in FIG. 3, and the film expanding means H has an endless shape like the film feeding means shown in the previous embodiment. A film holding portion 22 composed of a pair of upper and lower grips is attached to a moving member 21 such as a chain or a belt at predetermined intervals, and the expanding means H is directed from the film holding means B side toward the film feeding means C side. It is arranged so as to spread out in a substantially C-shape on a plane. As for the transfer of the film from the film expanding means H to the film feeding means C, the starting end side of the film feeding means C is located inside the grip for expanding the film to the maximum width in the film expanding means H as shown in the operation explanatory view of FIG. Place it like
Ensure that the extended film can be delivered and received smoothly.

In this embodiment, the film is expanded only in the width direction of the product, but if the film is expanded in the length direction as well, the usage amount of the film can be further reduced, but the mechanism becomes complicated as a drawback.

[0037]

According to the present invention, the packaging method according to claim 1 wraps the objects to be packaged from the minimum size to the maximum size with the same film, so that the conventional automatic film switching mechanism is unnecessary, and the packaging is performed. The structure of the packaging machine can be simplified, and the packaging machine can be made smaller and lighter and the cost can be reduced. Further, in this case, by wrapping the film having the maximum size in the width direction with the film expanded in the width direction, the width of the film is narrower by one rank or more than the film width conventionally required for packaging the maximum size of the product. Since the film can be wrapped in a film, the amount of the film used can be reduced and the running cost can be reduced. Furthermore, film expansion (pre-stretch)
Since it is performed uniformly over the entire length of the film, the deformation of the film is small even if the expansion amount is increased, and the influence on the packaging finish is small. Therefore, it becomes possible to wrap products having different sizes over a wide range by using a film roll having a single film width with good appearance. Further, when the user stores a spare film roll, only one type may be stored, so that management is easy.

When the expansion amount of the film is changed according to the size of the object to be packaged as described in claim 2, it is possible to adjust the tensile strength of the film and the width of the film is increased. The width is optimal for wrapping the article to be packaged, the film is not wasted, and aesthetically pleasing packaging can be performed. By configuring the packaging machine for carrying out the above-described packaging method as set forth in claims 3 and 4, it is possible to easily change the expansion amount (pre-stretch amount) of the film according to the size of the object to be packaged. . Furthermore, in the packaging machine according to claims 3, 4, and 5, it is not necessary to separately provide a member for expanding the film, so that the structure can be simplified accordingly. Further, in the wrapping machine according to the fourth, fifth and sixth aspects, since the expansion of the film is completed at the time when the transport of the film is completed, the processing speed of the wrapping can be improved accordingly. Furthermore, since the packaging machine according to claims 5 and 6 expands sequentially during the transport of the film, the number of parts to be moved in the width direction for expansion may be small, so that the whole packaging machine can be downsized accordingly. Have.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view schematically showing a stretch wrapping machine according to the present invention.

FIG. 2 is a vertical sectional front view of FIG.

FIG. 3 is a perspective view showing a mechanism from film supply to film expansion in FIG.

FIG. 4 is a vertical sectional view showing the mechanism of FIG.

5 is an operation explanatory view showing a film expanding operation of the packaging machine shown in FIG.

FIG. 6 is an operation explanatory view showing another extension operation.

FIG. 7 is an operation explanatory view showing still another extension operation.

FIG. 8 is a perspective view showing a packaging machine provided with another film expanding mechanism.

9 is an enlarged cross-sectional view taken along line (X)-(X) of FIG.

FIG. 10 is an enlarged view showing an opened / closed state of the film holding portion shown in FIG. 8.

11 is an operation explanatory view showing a film expanding operation of the packaging machine of FIG. 8.

FIG. 12 is a perspective view showing a packaging machine provided with still another film expanding mechanism.

13 is an operation explanatory view showing a film expanding operation of the packaging machine of FIG. 12.

[Explanation of symbols]

 A ... Machine frame B ... Film holding means C, C '... Film feeding means D ... Cutter E ... Interval expanding means F ... Conveyor G ... Packaged object a ... Product placement part b ... Packaging part 1 ... Elevator 2 ... Film roll Arrangement part 4 ... Film roll

Claims (6)

[Claims] 1. A packaging method in which an object to be packaged is pushed up from below onto a film stretched on the upper part to cover the upper surface of the object to be packaged with the film, and then an end portion of the film is folded under the object to be packaged. (a) Use a stretch film that is one rank narrower than the one used to wrap the largest size item to be wrapped, and (b) use the film before pushing up the item to be wrapped. Equipped with a step of uniformly expanding in the width direction, (c) the same size film from the smallest size to the largest size, and more than the film used to wrap the largest size package in the past. A method for wrapping an article with a stretch film, which comprises wrapping with a film having a narrower rank than one rank. 2. The method for wrapping an article with a stretch film according to claim 1, wherein the amount of expansion of the film in the width direction before pushing up the article to be packaged is changed according to the size of the article to be packaged. 3. A stretch wrapping machine in which an object to be packaged is pushed up from below onto a film stretched on the upper part to cover the upper surface of the object to be packaged with the film, and then the end of the film is folded under the object to be packaged. A film feed means for sandwiching both side edges of the film in the width direction and conveying the film cut to a predetermined length to a packaging position, and a space expanding means for expanding the space in the width direction of the film feed means. After the film is conveyed to the packaging position and before the product is pushed up, the width of the film is uniformly expanded over the entire length of the film by expanding the widthwise interval of the film feed means by the interval expanding means. Stretch wrapping machine. 4. A stretch wrapping machine in which an object to be packaged is pushed up from below on a film stretched on the upper part to cover the upper surface of the object to be packaged with the film and then the end of the film is folded to the lower side of the object to be packaged. A film feed means for sandwiching both side edges of the film in the width direction and conveying the film cut to a predetermined length to a packaging position, and a space expanding means for expanding the space in the width direction of the film feed means. In the process of transporting the cut film to the packaging position, the width of the film is uniformly expanded over the entire length of the film by expanding the widthwise interval of the film feeding means by the interval expanding means. Wrapping machine. 5. A stretch wrapping machine in which an object to be packaged is pushed up from a lower side to a film stretched on the upper part to cover the upper surface of the object to be packaged with the film, and then an end portion of the film is folded to the lower side of the object to be packaged. A film holding means for holding the both side edges of the film in the width direction and pulling the film out, and then conveying the film cut to a predetermined length to a packaging position. The film holding means on the left and right sides of the film feeding means. The interval of the film, which is supplied from the film roll, is sequentially expanded in the width direction as it is conveyed to the packaging position, and the width of the film is uniformly expanded over the entire length of the film in a state where the film is conveyed to the packaging position. Stretch wrapping machine characterized by that. 6. A stretch wrapping machine in which an object to be packaged is pushed up from below onto a film stretched on the upper part to cover the upper surface of the object to be packaged with the film, and then the end portion of the film is folded to the lower side of the object to be packaged. , After pulling out the film while sandwiching both side ends in the width direction of the film, a film feed means for conveying the film cut to a predetermined length to a packaging position, a film supply section in which a film roll is arranged, A film width expanding unit that is arranged between the film feeding unit and the film supplying unit and sequentially expands the film supplied from the film roll in the width direction, and then transfers the film width to the film feeding unit. The stretch wrap is characterized in that the width of the film is evenly extended over the entire length of the film in a state where the film is transported to the wrapping position. Equipment.