JP2003191907A - Packaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging apparatus which can keep an article supported by a lift mechanism as long as possible when folding a film. <P>SOLUTION: The packaging apparatus includes front and rear clamps 53 and 54, a lift mechanism, and a rear folding plate 71. The lift mechanism has a center fore-and-aft support member 34b and a center support member 35a for supporting a bottom of an article G, and presses the article G against a film F held by the clamps 53 and 54 or the like. The rear folding plate 71 folds the film F onto a bottom of the article G. The center support member 35a of the center fore-and-aft support member 34b and the member 35a of the lift mechanism moves while supporting the article G when the film F is folded onto the bottom of the article G. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a packaging device, in particular
The present invention relates to a packaging device that performs a packaging operation of folding a peripheral portion of a film pressed against an article to be packaged into a bottom side of the article to be packaged.

[0002]

2. Description of the Related Art As a device for covering and sealing an object to be packaged such as fruits and vegetables and foods placed on a tray with a film,
So-called stretch packaging devices are widely known. In this stretch wrapping device, the object to be wrapped is pushed up against the film held in tension, the peripheral portion of the film is folded to the bottom side of the object to be heat-sealed, and the object to be wrapped is wrapped with the film.

An example of such a stretch wrapping device is
It is disclosed in JP-A-11-208611. Here, the object to be packaged is pushed up against the film by an elevator (lift mechanism), and the film is folded under the object to be packaged by the folding mechanism. Specifically, during the folding operation of the left and right folding plates, the elevator head tilts so that the left and right folding plates enter under the object to be packaged. Further, when the left and right folding plates enter below the article to be packaged, the elevator is lowered and the rear folding plate is advanced to the lower side of the article to be packaged. In this way, the left and right and rear edges of the film are folded downward, and the packaged object is pushed out by the pusher to the discharge conveyor on the front side. As a result, the front edge of the film that hits the front folding plate is folded under the object to be packaged. The film whose periphery is folded under the article to be packaged in this manner is heat-sealed by the heat generating function of the discharge conveyor.

[0004]

When the film is folded to the bottom side of the package, if the support of the lift mechanism continues to support the package, the support of the lift mechanism and the folding mechanism. May interfere with the members constituting the. In the packaging apparatus disclosed in the above publication, the elevator is lowered and then the rear folding plate is advanced to the lower side of the object to be packaged, thereby avoiding the interference between the elevator and the rear folding plate.

As described above, in order to avoid interference, it is possible to control so that the support of the lift mechanism is released during the folding operation, but in this case, the article to be packaged by the support of the lift mechanism is released. Will be released soon. Then, even if the support member other than the lift mechanism supports the object to be packaged, the support by the lift mechanism is quickly released, so that the object to be packaged becomes in an unstable supporting state after that, and depending on the property of the object to be packaged. It is also feared that the packaged item will warp.

An object of the present invention is to provide a wrapping device which can maintain a state in which an object to be packaged is supported by a supporting portion of a lift mechanism when the film is folded.

[0007]

A packaging apparatus according to a first aspect comprises a film holding mechanism, a lift mechanism, and a folding mechanism. The film holding mechanism holds the film under tension. The lift mechanism has a supporting portion that supports the bottom of the packaged object, and presses the packaged object against the film held by the film holding mechanism. The folding mechanism folds the peripheral portion of the film pressed against the article to be packaged by the lift mechanism to the bottom side of the article to be packaged. Then, at least a part of the supporting portion of the lift mechanism moves while supporting the object to be packaged when the film is folded on the bottom side of the object to be packaged.

Here, when the folding mechanism folds the peripheral portion of the film to the bottom side of the article to be packaged, the support portion (or part thereof) of the lift mechanism moves while supporting the article to be packaged. Therefore, the movement of the support portion (or a part thereof) of the lift mechanism while supporting the object to be packaged makes it possible to avoid interference between the lift mechanism and the folding mechanism at least in the initial stage of folding. As a result, when the film is folded, the state in which the object to be packaged is supported by the support portion of the lift mechanism can be maintained as long as possible.

It should be noted that, instead of pushing the article to be slid over the support section, the support section of the lift mechanism moves while supporting the article to be packaged. Even if there is, there is almost no problem of scratching or falling. The packaging device according to claim 2 is the packaging device according to claim 1, wherein the folding mechanism has a rear folding member. The rear folding member is arranged rearward and can move back and forth. The packaging device according to claim 2 further includes a first moving mechanism and a control unit. The first moving mechanism moves the rear folding member back and forth. The control unit controls the first moving mechanism,
The rear folding member is moved forward, and while the film is folded toward the bottom side of the package by the rear folding member, the package is moved forward. And, at least a part of the support portion, while the film is folded to the bottom side of the article to be packaged by the forward movement of the rear folding member and the article to be packaged moves forward, while supporting the article to be packaged forward. Move to.

Here, the back folding member causes the film to be folded toward the bottom side of the packaged object and moves the packaged object forward. In the case of adopting a configuration in which the object to be packaged moves when the film is to be folded toward the bottom side of the object to be packaged, if the object to be packaged is continuously supported by the supporting portion of the lift mechanism, The object to be packaged may be damaged by the friction with the supporting portion. In particular, when packaging fruits and vegetables without using a tray, if they are moved forward by a pusher or the like, there is a risk that the package may be damaged or tumbled due to rubbing or the like. Specifically, the supported portion of the packaged object (including the tray when the packaged object is a product placed on a tray) may be damaged by the friction caused by the slide. Therefore, when the article to be packaged is easily damaged, it is desirable to prevent the article to be packaged from sliding on the support portion as much as possible.

On the other hand, in the packaging apparatus of the second aspect, when the article to be packaged moves forward, the support portion (or a part thereof) of the lift mechanism moves forward while supporting the article to be packaged. Therefore, damage to the packaged item due to friction between the packaged item and the support portion of the lift mechanism can be suppressed. Further, since the article to be packaged moves forward in this case, the operator can easily take out the packaged article.

The support portion (or part thereof) of the lift mechanism may be moved by a dedicated drive device,
You may comprise so that it may be pushed and moved by the rear folding member. A packaging device according to a third aspect is the packaging device according to the second aspect, and the support portion has a first support portion and a second support portion. When the rear folding member approaches, the first support portion descends to avoid interference with the rear folding member. The second support portion moves forward while supporting the object to be packaged as the rear folding member moves forward.

Even if the support portion of the lift mechanism moves forward when the film is folded by the rear folding member, in order for the rear folding member to enter the bottom side of the package, the support portion of the lift mechanism is finally covered. Must be clear of the bottom of the package. On the other hand, the support portion of the lift mechanism has a certain size. Therefore, when the supporting portion of the lift mechanism is large, the rear folding member is caused to enter the bottom side of the article to be packaged, so that it is necessary to lower the supporting portion of the lift mechanism at a relatively early timing after starting to move. .

Therefore, in the packaging apparatus according to the third aspect of the present invention, the supporting portion having at least the first supporting portion and the second supporting portion is adopted, and the first supporting portion is lowered as the rear folding member approaches.
Only the second support portion is moved forward while supporting the object to be packaged. Therefore, even if the supporting portion as a whole is large, if the second supporting portion is small, the state in which the second supporting portion of the lift mechanism supports the article to be packaged is maintained as long as possible. Then, by supporting the second supporting portion at a position where undesired deformation of the packaged object is suppressed, it is possible to prevent the packaged object from being warped during the folding operation by the rear folding member.

Further, since only the second supporting portion of the lift mechanism needs to be moved forward, a comparatively small force is required to be applied, and even when the structure is moved forward by a dedicated drive device, the rear folding member is used. Even in the case of adopting a configuration in which the structure is pushed to move forward, the load on the drive system is reduced. A packaging device according to a fourth aspect is the packaging device according to the third aspect, wherein the second support part receives the force from the rear folding member and moves forward.

In view of the fact that a relatively small force is required to move the second support portion of the lift mechanism, the second support portion is moved by receiving the force from the rear folding member. Therefore, it is not necessary to provide a separate drive device for moving the second support portion, and the above-described effects of the present invention can be obtained at low cost. A packaging device according to a fifth aspect is the packaging device according to the fourth aspect, wherein the second support portion receives a force from the rear folding member and becomes smaller in the front-rear direction.

When it is necessary to insert the rear folding member into the bottom side of the packaged article supported by the second support section,
The support also needs to descend after moving. Even in such a case, in the packaging apparatus according to the fifth aspect, the second support portion is made smaller in the front-rear direction so that the article to be packaged can be supported by the second support portion as long as possible. . Then, since the second support portion receives a force from the rear folding member and becomes smaller in the front-rear direction, the object to be packaged is longer supported by the second support portion as much as it becomes smaller.

A packaging apparatus according to a sixth aspect is the packaging apparatus according to any one of the third to fifth aspects, wherein the second support portion supports a portion including a center of a bottom portion of the article to be packaged. Here, the center of the bottom of the package is supported by the second support that continues to support the package for a longer period than the first support. Therefore, in the folding operation, the center of the bottom portion of the article to be packaged is continuously supported. As a result, it is possible to suppress a problem due to insufficient support such that the packaged object is warped during the folding operation.

A packaging apparatus according to a seventh aspect is the packaging apparatus according to any one of the third to sixth aspects, in which the second support portion moves forward after the first support portion descends. To descend. Here, since the second support part finally descends after the movement, the rear folding member can be inserted under the bottom part of the packaged object supported by the second support part and folded up to near the center of the bottom part. become able to.

A packaging apparatus according to an eighth aspect is the packaging apparatus according to the seventh aspect, and the lift mechanism further has a returning means. The returning means moves the plane position of the second support portion rearward when the second support portion descends or after the second support portion descends. Here, the second support portion, which has been moved forward with respect to the first support portion at the time of descending, is moved backward by the returning means. Therefore, when the lift mechanism supports the object to be packaged in order to press the next object to be packaged against the film, the second support part returns to the position where it properly supports the object to be packaged together with the first support part. There is.

The return means may be one that returns the second support portion to its original position by using a guide guide or the like by utilizing inertial force, or by using a force applying member such as a spring. Two
The support portion may be returned to the first support portion side. A packaging device according to a ninth aspect is the packaging device according to the second aspect, further including a second moving mechanism. The second moving mechanism moves at least a part of the support portion back and forth. The control unit controls the second moving mechanism when moving the object to be packaged forward while controlling the first moving mechanism to fold the film to the bottom side of the object to be packaged by the rear folding member. At least a part of the support is moved forward.

Here, a second moving mechanism for moving the supporting portion (or a part thereof) of the lift mechanism back and forth is provided separately from the first moving mechanism. For this reason, it is possible to move the rear folding member and the supporting portion of the lift mechanism forward by separate driving without causing the rear folding member and the supporting portion of the lift mechanism to collide with each other.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION <Overall Configuration and Schematic Operation> FIGS. 1 to 3 are a schematic side view, a front view, and a plan view of a stretch wrapping apparatus according to an embodiment of the present invention. A control block of the stretch wrapping device 10 is shown in FIG. This stretch wrapping device 10 is a small-sized weighing and wrapping price device, and is designed for wrapping fruits and vegetables in a notebook tray or wrapping foods (products) such as fruits and vegetables stored in a soft tray. However, packaging is possible even for products placed on ordinary foam trays.

The stretch wrapping device 10 has a weighing function and a pricing function (label creating function including weighing value and price).
However, here, the description will focus on the packaging function of the stretch packaging device 10. The stretch wrapping device 10 is a device in which each mechanism is attached to the main body frame 15, and is mainly a product introduction mechanism 20, a lift mechanism 30, a film transport mechanism 40, a film holding mechanism 50, and a film pushing mechanism. 60, a film film left-right folding mechanism 66, and a heat-sealing / film front-back folding mechanism 70.

When a product G (see the product G on the front side in FIG. 1) is placed on the introduction table 21 of the product introduction mechanism 20 by the operator's hand, the product G is weighed by the weighing device 29 and then the product G is measured. G is sent to the lift mechanism 30 (see FIG. 1).
See item G on the back). On the other hand, the film transport mechanism 40
The film F conveyed by the lift mechanism 30 is pre-stretched by the film holding mechanism 50 while holding the front, rear, left, and right ends thereof (FIG. 10B).
reference). When the product G supported by the lift mechanism 30 is pushed up against the pre-stretched film F, the product G pushes the film F and the film F is pushed up.
The upper and lateral sides are covered by (Fig. 10
(See (c)).

The peripheral portion of the film F which covers the upper and side portions of the product G in this manner is folded to the bottom side of the product G by the left and right pushing members 61, 62 and the rear folding plate 71 (see FIG. 10 (e)). ). Prior to this folding operation, the left and right folding plates 64 and 65 enter the vicinity of the left and right ends of the bottom of the product G and play a role of supporting the bottom of the product G together with the lift mechanism 30. The film F folded on the bottom side of the product G receives heat input from the nichrome wire 81 attached to the front fixing member 72 while being sandwiched between the rear folding plate 71 and the front fixing member 72. , Heat sealed (Fig. 13
(See (d)).

The product G thus wrapped with the film F including the heat seal is taken out by the operator's hand, and the label discharged from the pricing mechanism (not shown) is attached. <Structure of Product Introduction Mechanism 20> The product introduction mechanism 20 is shown in FIG.
As shown in FIG. 4 and FIG. 4, it mainly includes an introduction table 21, an introduction table vertical movement motor 22, and an introduction table longitudinal movement motor 23. The introduction table 21 supports the product G by a plurality of support plates 21a arranged in the left-right direction. These support plates 21a and the support members 34a, 34b, 35a (described later) of the lift mechanism 30 shown in FIG. 7 are arranged so as to be displaced in the left-right direction. Below the introduction table 21, a weighing instrument 29 for measuring the weight of the product G placed on the introduction table 21 is arranged. The introduction table 21 is connected to the introduction table forward / backward movement motor 23 via a belt, a pulley, or the like, and is moved back and forth by the operation of the introduction table forward / backward movement motor 23. In addition, the introduction table 21 and the introduction table longitudinal movement motor 2
The entire front-back motion unit including 3 is the introduction table vertical motion motor 2
It is configured to move up and down by 2.

When the motors 22 and 23 of the product introduction mechanism 20 are operated by a command from the control unit 90 which will be described later, the introduction table 21 makes a rectangular motion, and the product G placed on the introduction table 21 by the walking beam system. It is sent onto the support members 34a, 34b, 35a of the rear lift mechanism 30. <Structure of Lift Mechanism 30> The lift mechanism 30 is provided to support the bottom portion of the product G sent from the product introduction mechanism 20 and lift the product G upward. The lift mechanism 30 also plays a role of supporting the bottom of the product G when the peripheral portion of the film F is folded to the bottom of the product G, as described later.

As shown in FIGS. 1, 2, 4 and 5, the lift mechanism 30 mainly includes vertical rails 30a arranged on the left and right, a slider 31a which moves up and down along the vertical rail 30a, and a link. A mechanism 30c, a lift motor 30d for moving the slider 31a up and down via the link mechanism 30c, and a first motor mounted on the slider 31a.
The base 31 and the second base 3 that moves up and down along a small rail 31b extending downward from the center of the upper portion of the first base 31.
2 and. The lift mechanism 30 also includes a return mechanism and a time difference lowering solenoid switch 37.

The link mechanism 30c is a lift motor 30.
By the operation of d, the pin support portion 30b is rotated to move the slider 31a and the first base 31 to the vertical rail 30.
Move up and down along a. [First Base 31] The first base 31 is shown in FIGS.
As shown in FIG. 5, the slider 31a is formed integrally with the left and right support members 34a and the center front and rear support members 34b.
And have. The first base 31 has a portion that is divided into seven parts on the left and right, and a support member 34a (or 34b) extends upward from each of the divided parts.
The left and right support members 34a have a horizontal surface on the upper surface that supports the product G, and three left and right support members 34a are arranged on each side. The left and right support members 34a have a structure such that the upper portions thereof can be collapsed inward, and when the left and right folding plates 64, 65 and the left and right pushing members 61, 62 described later come inward, the left and right folding plates 64, 65. It falls inward due to the force acting from etc. On the other hand, the central front-back support member 34b is
It extends upward from the central one of the divided first bases 31, and does not have a falling structure. Also,
The central front-back support member 34b is the central support member 35 described later.
Along with a, it plays a role of supporting the central portion of the product G in the left-right direction from below, but it is formed in a concave shape in a side view together with the central support member 35a so that the product G is stably supported (FIG. 5). (See (a)). The central front-rear support member 34b supports a front portion and a rear portion of the center portion of the product G in the left-right direction.

The two small rails 31b are provided on the first base 3
1 extends downward from the center of the upper part. The small rails 31b are the left and right support members 3 fixed to the first base 31.
4a and the center front-back support member 34b, and the 2nd base 32.
It is provided to vertically move the central support member 35a, which is pin-supported by the. [Second Base 32] In the second base 32, a slide portion 32a, which is a rear portion, is engaged with a small rail 31b so as to be slidable up and down. Therefore, the second base 3
2 can move up and down relatively to the first base 31. In addition, at the lower ends of the two small rails 31b, the sliding portion 32a of the second base 32 has the small rails 3a.
It is connected by a member for preventing it from falling off from 1b. A stopper bolt is attached to a member connecting the lower ends of the two small rails 31b, and the head of the bolt supports the lower surface of the slide portion 32a of the second base 32 from below. Therefore, when the slider 31a and the first base 31 rise, the second base 32 also rises.

The second base 32 includes four link bars 3
The central support member 35a is supported by 5b. The center support member 35a is two plate-shaped members for supporting the center portion of the bottom of the product G. This central support member 35
The upper surface of a is concave as seen in a side view as shown in FIG. An upper portion of the link bar 35b is pin-joined to the central support member 35a, and a lower portion thereof is pin-joined to the second base 32. These link bars 35b are
It plays a role of moving the central support member 35a forward and backward with respect to the second base 32 by a predetermined distance. That is, the central support member 35a is configured to move back and forth within a predetermined range with respect to the second base 32 fixed in the front-rear direction (see FIGS. 5B and 5C).

The slide portion 32a of the second base 32 is also provided.
An extension member 32b extends downward from the rear end. The extension member 32b has its lower end bent backward to form a horizontal portion 32c. The horizontal portion 32c is supported from below by a shaft 37a of a solenoid switch 37, which will be described later, when the peripheral portion of the film F is folded into the bottom portion of the product G (see FIG. 5A).

[Return Mechanism] The return mechanism of the lift mechanism 30 has a structure in which the second base 32 supports the central support member 35a so as to be movable back and forth via the link bar 35b.
It is composed of a guide roller 36a provided at the front end of the base 31. The guide roller 36a includes the first base 31
Is rotatably supported at the front end of the central support member 35.
It prevents the a from moving forward more than necessary and plays a role of restricting the forward movement of the central support member 35a by hitting the central portion of the front link bar 35b (see FIG. 5C). Further, the guide roller 36a plays a role of guiding the central support member 35a so as to return to the rear when the first base 31 descends first and the second base 32 descends later.

When the second base 32 descends after the first base 31 descends first, a backward reaction force from the guide roller 36a to the front link bar 35b (reaction against the downward inertial force of the central support member 35a). Force) acts. For example, in the state shown in FIG. 6A, a backward force acts on the link bar 35b from the guide roller 36a. Thereby, the central support member 35a
Moves back to the original position (see FIG. 6B).

The stopper 32d works when the central support member 35a returns to the original front-rear position so that the central support member 35a does not move rearward more than necessary. The stopper 32d is provided at the front end of the second base 32, and restricts the forward movement of the lower end of the rear link bar 35b to prevent excessive rearward movement of the central support member 35a.

[Solenoid switch 37 for decreasing the time difference]
Solenoid switch 37 for lowering the time difference of the lift mechanism 30
Is fixed to the body frame 15. The solenoid switch 37 is actuated immediately after the first and second bases 31, 32 are raised to the highest point, and their shaft 37a is operated.
Supports the lower surface of the horizontal portion 32c of the second base 32 from below (see FIG. 5A). As a result, the second base 32
Even if the first base 31 is lowered as shown in FIG. 5B, the height position is maintained as it is until the solenoid switch 37 is turned off.

<Structure of Film Conveying Mechanism 40> The film conveying mechanism 40 conveys the film F cut into a predetermined size above the product G supported by the lift mechanism 30, and causes the film holding mechanism 50 to hold the film F under tension. It is a mechanism. The film transport mechanism 40 mainly moves the roll holding unit 41 that rotatably supports the film roll R, the front clamp 54 that holds the leading end of the film F fed from the film roll R, and the front clamp 54 back and forth. It is composed of a front clamp moving mechanism.
The front clamp moving mechanism is the front clamp longitudinal movement motor 5
6a (see FIG. 4), a belt mechanism, a front clamp support member, and the like. Here, the front clamp 54 is moved back and forth by operating the front clamp forward / backward movement motor 56a. The front clamp 54 grips or separates the front end portion of the film F by turning on / off the front clamp solenoid switch 56b shown in FIG.

When the controller 90 issues a command to convey the film F, the front clamp 54 moves backward,
The leading end of the film F that has been fed from the film roll R and has reached the vicinity of the rear clamp 53 is grasped. Then, the front side clamp 54 moves forward while holding the leading edge of the film F, so that the film F is lifted by the lift mechanism 30.
Will be located above.

<Structure of Film Holding Mechanism 50> The film holding mechanism 50 mainly includes a front clamp 54 and a front clamp moving mechanism, which are also components of the film transport mechanism 40, a rear clamp 53 and a rear clamp moving mechanism. It is composed of a left clamp 51, a right clamp 52, and a left and right pushing member moving mechanism which is also a component of a film pushing mechanism 60 described later.

The rear clamp 53 is for holding or separating the rear end of the film F by turning on / off the rear clamp solenoid switch 55b shown in FIG. Moving. The rear clamp moving mechanism is the rear clamp longitudinal movement motor 55.
a (see FIG. 4), a belt mechanism, a rear clamp support member, and the like.

The left clamp 51 and the right clamp 52 are
As shown in FIG. 9, the film F is provided below the left and right pushing members 61 and 62, which will be described later, and the film F is pushed by the left and right pushing members 6.
The film F is gripped by being sandwiched between the films F and 62. That is, the left clamp 51 and the right clamp 52
Moves up and contacts the left and right pressing members 61 and 62 to grip the film F, and moves down to separate from the left and right pressing members 61 and 62 to release the grip of the film F. Therefore, in order to move the left clamp 51 and the right clamp 52 up and down, as shown in FIG.
A left clamp vertical movement motor 51a and a right clamp vertical movement motor 52a are provided. When the left clamp vertical movement motor 51a and the right clamp vertical movement motor 52a operate, the left clamp support base 51b and the right clamp support base 52b supporting the left clamp 51 and the right clamp 52 move up and down.

Further, the left clamp 51 and the right clamp 5
2 is supported by a left clamp support base 51b and a right clamp support base 52b so as to be movable left and right by a predetermined distance. Then, by moving left and right, the left clamp 5
1 and the right clamp 52 do not draw an arc-shaped trajectory,
The left clamp 51 and the right clamp 52 are configured to be able to move slightly up and down with respect to the left clamp support base 51b and the right clamp support base 52b. Therefore, when the left and right pushing members 61, 62 move left and right while the left clamp 51 and the right clamp 52 are pressed against the left and right pushing members 61, 62 from below, the left clamp 51 and the right clamp 52 follow the movement. . That is, the left and right pushing member moving mechanism that moves the left and right pushing members 61 and 62 to the left and right also serves to move the left clamp 51 and the right clamp 52 to the left and right.

The film holding mechanism 50 plays a role of gripping the peripheral portion of the film F when the product G is pushed up by the lift mechanism 30, and the film F is held immediately before the product G is pushed up. Perform a pre-stretching action to put the tension. By this pre-stretching operation, the respective clamps 53, 54, 51, 52 holding the peripheral portion of the film F horizontally move outward and the film F is stretched by a predetermined amount.

<Structure of Film Pushing Mechanism 60> The film pushing mechanism 60 is composed of left and right pushing members 61, 62 and a left and right pushing member moving mechanism for moving these pushing members 61, 62 left and right. The left and right pushing member moving mechanism includes a film pushing motor 63a shown in FIG. 4, a belt mechanism, and a support member that supports the left and right pushing members 61 and 62. The film pushing motor 63a operates according to a command from the control unit 90, and the left and right pushing members 6 are driven.
Move 1, 62 left and right.

Further, the left and right pushing members 61 and 62 can hold the film F by sandwiching the film F between the left clamp 51 and the right clamp 52, and act as a part of the clamp. Left and right pushing member 6
1, 62 are formed with elongated holes for strengthening the clamping action. Since the same applies to any of the pushing members 61 and 62, the elongated hole 61a formed in the left pushing member 61 shown in FIG. 9B will be described here. The long hole 61a is formed to be long in the front-rear direction, and has a size into which the protruding portion 51c protruding upward from the upper surface of the left clamp 51 can be inserted. When the left clamp 51 moves upward and comes into close contact with the pushing member 61, the protrusion 51c of the left clamp 51 enters the elongated hole 61a, and the film F enters between the protrusion 51c and the elongated hole 61a.
The lateral movement of the film F is strongly restricted. Thus, due to the presence of the protrusion 51c and the long hole 61a,
The grip degree for gripping the film F is enhanced by the clamp 51 and the pushing member 61.

<Structure of the left and right film folding mechanism 66> The left and right film folding mechanism 66 is mainly composed of the left and right folding plates 6.
4, 65 and left and right folding motors 68a for moving the left and right folding plates 64, 65 to the left and right (see FIG. 4).
It consists of and. The left-right folding motor 68a moves the folding plates 64, 65 left and right via a belt mechanism, a support member that supports the folding plates 64, 65, and the like.

The left and right folding plates 64 and 65 are disposed above the left and right pushing members 61 and 62, and the rear folding plate 7 will be described later.
The bottom of the product G is supported during the film folding operation by 1. <Structure of heat seal / film front / rear folding mechanism 70> The heat seal / film front / rear folding mechanism 70 operates after the left and right end portions of the film F covering the product G are folded under the product G, and is operated after the film F. This is a mechanism in which the end portion is folded under the product G, and the film F is sandwiched below the product G for heat sealing.

The mechanism 70 mainly comprises a rear folding plate 71.
And a rear folding plate moving mechanism, a rear clamp 53 and a rear clamp moving mechanism (described above), a front fixing member 72,
Front clamp 54 and front clamp moving mechanism (described above)
And a nichrome wire 81 and a thermistor 82 mounted on the front fixing member 72. The rear folding plate 71 is
Left and right pushing members 61, 62 and left and right folding plates 6 in the height direction
4 and 65, and the film F is folded from the back to the bottom side of the product G, and the front side fixing member 7
The film F is sandwiched between the two and the film F to give a pressing force necessary for heat sealing. The rear folding plate moving mechanism includes a rear folding plate moving motor 71a (see FIG. 4), a belt mechanism, a support member for supporting the rear folding plate, and the like. When the rear folding plate moving motor 71a operates according to a command from the control unit 90, the rear folding plate 71 moves back and forth.

The rear folding plate 71 has a main body 71b whose front surface is roughened in the range shown in FIG. 3 and has a rough surface. A bakelite member 71c is attached to the tip of the rear folding plate 71, as shown in FIG. The bakelite member 71c is made of a material having appropriate hardness, heat resistance, wear resistance, and insulation. With such a configuration, the portion of the rear folding plate 71 that comes into contact with the film F when the film F is folded is in a state in which the film F is hard to adhere.

The front side fixing member 72 is fixed to the body frame 15. The front side fixing member 72 is an aluminum plate 7
2a, a stainless plate 72b, and a roller 72c. Aluminum plate 72a is stainless steel plate 72b
And the roller 72c, and is arranged at a position sandwiched vertically. A nichrome wire 81 is attached to the rear surface of the aluminum plate 72a (the surface facing the rear folding plate 71). The nichrome wire 81 is located on the front side of the rear surface of the stainless plate 72b and the rear end of the roller 72c. To retract into
A stainless plate 72b and a roller 72c are arranged. Nichrome wire 81 (height dimension 2 mm) is made of aluminum plate 7
It is attached to the rear surface (height dimension 5 mm) of 2a via an insulating tape.

In order to estimate the amount of heat applied to the film F from the nichrome wire 81 by measuring the temperature of the aluminum plate 72a, the thermistor 8 which is a temperature sensor.
2 is embedded in the aluminum plate 72a. further,
The aluminum plate 72a is divided into two parts, left and right, and absorbs the expansion of the nichrome wire 81 according to the thermal expansion.

<Details of Operation of Stretch Wrapping Device 10> Next, in the operation of the stretch wrapping device 10, the film F
A detailed description will be given of the operation of folding the film F from the left and right to the bottom side of the product G and the operation of folding the film F from the rear to the bottom side of the product G to heat seal the film F. [Left and right folding operation and pushing operation] Fig. 10 (a)
As shown in FIG. 4, when the film F is transported by the film transport mechanism 40 above the lift mechanism 30, the left and right clamps 51, 52 are raised and the left and right pushing members 61, 6 are pushed.
The left and right parts of the film F are gripped between the two. At this time, the front and rear parts of the film F are also held by the front and rear clamps 53 and 54.

Next, the left and right pushing members 61, 62 and the left and right clamps 51, 52 following them are opened outward, and the film F is pre-stretched in the left-right direction (see FIG. 10B). At this time, the film F is also pre-stretched in the front-back direction. The lift mechanism 3 is applied to the film F that has been pre-stretched and wrinkle-free.
0 raises the product G placed on the support members 34a, 34b, and 35a, and the film G is pushed up by the product G (see FIG. 10C). At this time,
The product G is the film F when the film F is pushed up.
The upper and lateral sides are covered by.

As shown in FIG. 10C, when the product G pushes up the film F, the left and right folding plates 64, 6
5 comes in first, and a little later, the left and right pushing members 61, 62 and the rear folding plate 71 also come in. The left and right folding plates 64 and 65 are the product G
When it reaches the position where it can support the bottom of the, the movement is stopped. On the other hand, the left and right pushing members 61, 62 and the left and right clamps 51, 52 which follow them are provided with the left and right folding plates 64, 65 so that excessive tension does not act on the film F due to the movement of the left and right folding plates 64, 65. Then, while moving inward, the left and right clamps 51 and 52 are lowered at appropriate positions to release the grip of the left and right portions of the film F (see FIG. 10D).

Even after the left and right portions of the film F are released, the left and right pushing members 61 and 62 continue to move inward to push the film F to the bottom side of the product G, and finally the left and right folding plates 64, It moves to the inside of 65 and stops (see FIG. 10 (e)). The left and right folding plates 64, 65 and the left and right pushing members 6 in plan view at this time
The positional relationship between the rear folding plates 71 and the front fixing member 72 is shown in FIG.

In the left and right folding operation,
Regarding the support of the product G by the lift mechanism 30, the support by the central front-rear support member 34b and the central support member 35a continues, and the support by the left and right support members 34a is replaced by the support by the left and right folding plates 64, 65. Left and right folding plates 6
When 4, 5 enter the inside, the left and right support members 34a are pushed by the left and right folding plates 64, 65 in order from the outer side and fall inward.

[Post-folding operation and heat-sealing operation] By the above-mentioned left-right folding operation and pushing operation, FIG.
The product G and the film F in the state shown in 0 (e) and FIG. 11 are in a state as shown in FIG. 12 (a) in a side view. In the rear folding operation, first, the rear folding plate 71 moves forward, and after a short delay, the rear clamp 53 moves forward. After that, the rear clamp 53 moves forward in accordance with the movement of the rear folding plate 71 so that the excessive tension does not act on the film F (see FIG. 12B).

Then, when the rear folding plate 71 approaches the lift mechanism 30, the first base 31 descends, and the support of the product G by the central front and rear support member 34b is released (FIG. 12).
(See (c)). At this time, although the first base 31 is lowered by the lift motor 30d, the time difference lowering solenoid switch 37 maintains the same state, so that the second base 32 does not lower and stays at the same height position. Therefore, for a while after the first base 31 is lowered, the product G is supported only by the central support member 35a supported by the second base 32 and the left and right folding plates 64, 65.

When the rear folding plate 71 further advances and hits the central supporting member 35a of the lift mechanism 30, the rear folding plate 71 is pushed forward by the force and the central supporting member 35a.
Starts moving forward (see FIG. 10D). Accordingly, the product G also starts moving forward. Further, as the center support member 35a and the product G move forward, the front clamp 54 moves backward to maintain the tension of the film F on the front side of the product G appropriately (FIGS. 13A and 13 (a). See b)). 1 is a plan view of the rear folding plate 71 and the like when the center support member 35a is moving forward while supporting the product G.
4 shows.

When the center support member 35a of the lift mechanism 30 and the product G approach the front side fixing member 72, the shaft 37a of the time difference lowering solenoid switch 37 retracts, and the second base 32 and the center support member 35a descend ( 5 (c), 6 (a) and 6 (b)). As a result, there is no obstruction to the entry of the rear folding plate 71 or the rear clamp 53 below the product G, and the rear folding plate 7
1 and the rear clamp 53 move further forward (see FIGS. 13B and 13C). Also at this time, the product G that receives a forward force from the rear folding plate 71 via the film F slides on the left and right folding plates 64 and 65 and continues to move forward.

Finally, the rear folding plate 71 hits the front side fixing member 72, specifically, the bakelite member 71c of the rear folding plate 71 hits the nichrome wire 81 of the front side fixing member 72, and the front film F and The film F on the rear side is heat-sealed below the product G by pressing force and heat input from the nichrome wire 81 (see FIG. 13D). It should be noted that the rear clamp 53 and the front clamp 54 are provided at or immediately before the heat input from the nichrome wire 81.
The holding of the film F by is released. This is to prevent the tension of the film F from changing when heat is applied.

After that, the rear folding plate 71 and the rear clamp 53 return to the rear, and the product G covered with the film F and heat-sealed is supported by the front portions of the left and right folding plates 64 and 65. It will be in a state of being. <Structure of Control Unit 90 and Characteristic Control by Control Unit 90> The control unit 90 controls each mechanism 2 of the stretch wrapping apparatus 10.
It controls the operations of 0, 30, 40, 50, 60, 66 and 70. The control unit 90 includes a storage unit 9 such as a RAM.
Have one.

External storage, manual input,
Alternatively, the information about the product G and the information about the film F collected by the input from the scale 29 or the like are stored. [Control for left-right folding operation and pushing operation]
The control unit 90 controls the film pushing motor 63a and the left and right folding motor 68a on the basis of the control data including the properties of the product G and the film F in the storage unit 91, and the left and right pushing members 61, 62 and Left and right folding plates 6
The movement amount and the movement timing of 4,65 are optimized for the product G and the film F. As the control data, data regarding whether or not the product G includes a tray,
The data on the shape of the product G or the tray, the data on the size of the product G or the tray, the data on the rigidity of the product G or the tray, the data on the size of the film F, the data on the type of the film F, etc. Film size, film type, tray depth / width / height, tray softness, shape of product G (round, etc.), height of product G, whether product G is on a hard tray or soft tray Control data is used which consists of information as to whether it is on or if the product G is to be packaged without a tray.

Further, the release timing of the left and right portions of the film F in the left and right folding operation, that is, the timing of lowering the left and right clamps 51 and 52 is also controlled based on the above control data. [Control Regarding Rear Folding Operation] The control unit 90, based on the information on the properties of the product G and the film F in the storage unit 91,
The rear folding plate moving motor 71a, the rear clamp front-rear movement motor 55a, and the front clamp front-rear movement motor 56a are controlled. Specifically, the rear folding plate 7 driven by the rear folding plate moving motor 71a is provided so that excessive tension does not act on the film F.
In order to control the rear clamp forward / backward motor 55a that moves the rear clamp 53 in accordance with the movement of No. 1, and to keep the tension of the front film F, which changes due to the forward movement of the product G, within a proper range. The front clamp forward / rearward movement motor 56a that moves 54 is controlled. This allows
It is possible to prevent the film F from being excessively tensioned to form holes in the film F and the product G from being subjected to an excessive force.

[Control Regarding Heat Sealing Operation] Control Unit 90
When the front film F and the rear film F are sandwiched by the rear folding plate 71 and the front fixing member 72 below the product G, nichrome produces a large voltage or current (impulse) that lasts for a very short time. Heat is applied to the film F by flowing it through the wire 81. That is, here, an impulse seal capable of changing the amount of heat input to the heat-sealed portion with good responsiveness is employed.

Then, the control section 90 controls the front side fixing member 72.
Based on the temperature measured by the thermistor 82 embedded in the aluminum plate 72a, at least one of the current value, voltage value, number of times, and energization time of the impulse flowing through the nichrome wire 81 is changed. Therefore, the film F can be heat-sealed with a sufficient amount of heat input. For example, when the temperature of the front side fixing member 72 rises and falls due to changes in the surrounding environment, the temperature change is measured by the thermistor 82, so the nichrome wire 81 is controlled so that heat sealing is appropriately performed. be able to. Specifically, when the ambient temperature is low in winter, the temperature of the aluminum plate 72a may be lowered and the amount of heat required for heat sealing may be insufficient. Therefore, the impulse seal is controlled to compensate for this.

<Left and right clamps 51, 52 before operation
Positioning> Here, the left and right clamps 51 and 52 are configured to move left and right following the left and right movements of the left and right pushing members 61 and 62.
It does not have a drive mechanism that can move left and right. On the other hand, the applicant of the present application, based on the lateral width W3 of the film F and the lateral width W1 of the product G (see FIG. 9A),
It has been found that it is desirable to properly determine the initial positions of the left and right clamps 51 and 52. Especially film F
When the width W3 of the product G is long and the width W1 of the product G is short, unless the left and right clamps 51 and 52 are arranged at appropriate initial positions, it becomes impossible to secure a sufficient pre-stretch amount in the left-right direction or necessary pre-stretching. In some cases, the distance that the left and right clamps 51 and 52 have to move to obtain the amount becomes large.

In view of this, in the stretch wrapping device 10, the distance W2 (see FIG. 9A) between the left and right clamps 51 and 52 with respect to the width W3 of the film F and the width W1 of the product G is set to an appropriate value. As described above, a method is adopted in which the operator determines the initial positions of the left and right clamps 51 and 52 in the left and right direction. Specifically, the left clamp support base 51
b and the right clamp support base 52b are fixed to the main body frame 15 in the left-right direction below, the width W of the film F is set in advance in several steps.
3 and the operator determines the fixed position by using the table in the operation manual that can derive the fixed position from the width W1 of the product G. Therefore, when the width W3 of the film F or the width W1 of the product G changes, the left clamp support base 51b
The fixing position for fixing the right clamp support base 52b and the right clamp support base 52b in the left-right direction is changed, and the left clamp support base 51b and the right clamp support base 5 as shown by an arrow A in FIG.
The left and right position of 2b changes.

<Characteristics of Stretch Wrapping Device 10> (1) In the stretch wrapping device 10, the left and right pushing members 6 are
Film pushing motor 63 for moving 1, 62
Separately from a, a left and right folding motor 68a for moving the left and right folding plates 64 and 65 is provided, and a product G or a film F is provided.
Both motors 63a and 68a are controlled based on control data consisting of information relating to the properties of Therefore, here, the movements of the left and right pushing members 61 and 62 and the movements of the left and right folding plates 64 and 65 can be controlled separately, and the movement of the left and right folding plates 64 and 65 can be controlled independently. When to start moving the pushing members 61, 62,
The amount of movement of the left and right pushing members 61 and 62 and the amount of movement of the left and right folding plates 64 and 65 can be appropriately adjusted according to the properties of the product G and the film F.

As a result, when the film F or the product G is changed, the left and right pushing members 61 and 62 and the left and right folding plates 6 are formed.
The problem that the cooperation of the movements with 4, 65 is out of the appropriate range and the desired tension of the film F cannot be obtained is suppressed. In addition, here, the left and right pushing members 61,
Since 62 respectively has a role of a clamp, the left and right folding plates 64, 65 with respect to the left and right pushing members 61, 62.
Has a great influence on the tension of the film F. Therefore, the left and right pushing members 61, 62
The above merit by controlling the movement of each of the left and right folding plates 64, 65 according to the properties of the film F or the product G is very effective from the viewpoint of optimizing the tension of the film F in the stretch packaging device 10. Is.

(2) In the stretch wrapping apparatus 10, the operator sets the initial positions of the left and right clamps 51 and 52 before operation as described above. That is, product G
The initial positions of the left and right clamps 51, 52 are corrected according to the width W1 of the film F and the width W3 of the film F.

Therefore, when the width W1 of the product G is short,
The left and right clamps 51 and 52 grip the film F not at the left and right ends of the film F but at the portions closer to the product G than that. Thus, the width W1 of the product G
When the left and right clamps 51 and 52 are short, the left and right clamps 51 and 52 are corrected to grip the left and right portions of the film F close to the product G, so that a sufficient amount of pre-stretching is ensured by a small movement of the left and right clamps 51 and 52 in the pre-stretching operation. Will be able to.

(3) In the stretch wrapping device 10, the film F is folded to the bottom side of the product G by the rear folding plate 71, and the rear folding plate 71 is brought into contact with the front fixing member 72 to be folded to the bottom side of the product G. The film F is sandwiched and pressure-bonded, and heat from the nichrome wire 81 is applied thereto to heat-seal the film F.

Since only the rear folding plate 71 is moved forward and the front side fixing member 72 is fixed to the front side so as not to move, the front side of the rear folding plate 71 moves to the bottom side of the product G of the film F. During the folding operation of the product G, the product G moves forward while being drawn to the film F. That is, when the film F is folded in such a way that both the front member and the rear member enter the lower side of the product G, the planar position of the product G does not change. Since the front side fixing member 72 is fixed, the commodity G comes to move to the front side during the folding operation. As a result, as can be seen by comparing FIGS. 12A and 13E, after the folding by the rear folding plate 71 is finished and the film F is heat-sealed on the bottom side of the product G, the flat surface of the product G is obtained. The target position is on the front side (on the front side of the apparatus 10) with respect to the position where the product G is pushed up with respect to the film F held in tension. Therefore, the operator can easily take out the product G that has been heat-sealed and wrapped.

As described above, in the stretch wrapping device 10, the product G can be moved to the front side of the device 10 even though the pusher which is conventionally used is not provided, and the operator can take out the product G. It is easier. In addition, the pusher is a product G as in the past.
Since the product G is not directly pressed to push the product G, it is possible to prevent the product G from being damaged in a notebook tray packaging or the like.

At the final stage of moving the product G forward when the film F is folded by the rear folding plate 71,
Since the front clamp 54 is moved rearward, it is possible to prevent excessive tension from being applied to the film F, and to prevent the phenomenon that the forward movement of the product G is hindered. That is, by moving the front clamp 54 backward, the product G comes out further forward.

(4) In the stretch wrapping device 10, since the nichrome wire 81 is attached to the front fixing member 72 instead of the rear folding plate 71, the movement of the nichrome wire 81 and the portion related to the nichrome wire 81 is considered. No need to put it in. This makes it easier to secure the durability of the nichrome wire 81 and the like as much as it does not move, and the cost can be reduced. That is, when the member to which the nichrome wire 81 is attached moves, the external load on the nichrome wire 81 increases and the cost of parts for ensuring durability increases, but here the front side fixing member 72 is used. Since the nichrome wire 81 is attached to the above, the durability of the device 10 can be secured at low cost.

Further, the nichrome wire 81 and the front side fixing member 72
Does not move, it is easy to provide a thermistor 82 for monitoring the heat-sealed portion. (5) Conventionally, when the impulse seal application condition is determined, the condition of a certain voltage and time is determined by a test. Therefore, there is a problem that the ambient temperature cannot be taken into consideration. In addition, the conditions are basically settings that cannot be changed.

On the other hand, in the stretch wrapping device 10, based on the temperature measured by the thermistor 82 embedded in the aluminum plate 72a of the front side fixing member 72, the current value, the voltage value, the number of times of the impulses flowing through the nichrome wire 81, and the At least one of the energization times is changed. For this reason,
The film F can be heat-sealed with a sufficient amount of heat input.

The thermistor 82 is attached to the front side fixing member 72.
Even if the rear folding plate 71 hits the front side fixing member 72, the thermistor 82 does not come off from the front side fixing member 72 due to an impact. (6) In the stretch wrapping device 10, when the rear folding plate 71 folds the rear portion of the film F to the bottom side of the product G, the central support member 35a of the lift mechanism 30 moves while supporting the product G. Therefore, the lift mechanism 3 is moved by the movement of the central support member 35a while supporting the product G.
The interference between 0 and the rear folding plate 71 is avoided, and the state in which the product G is supported by the central supporting member 35a when the film F is folded is maintained as long as possible.

Further, since the central support member 35a moves forward while supporting the product G, the product G and the central support member 35.
It does not slide with a, and damage to the product G due to friction between the two G and 35a is suppressed. (7) In the stretch wrapping device 10, the central front-back support member 34b and the second base 3 supported by the first base 31.
The rear folding plate 7 is supported by the central support member 35a supported by
The product G is supported during the folding operation of the film F by 1, and the central front-rear support member 34b is provided as the rear folding plate 71 approaches.
Is first lowered, and the central support member 35a is moved forward with the product G supported. Therefore, the portion of the lift mechanism 30 that supports the product G is large as a whole, but the central support member 35a is small, so that the state where the central support member 35a of the lift mechanism 30 supports the product G is maintained as long as possible. Since the central support member 35a supports a position (a position that supports the center of the bottom of the product G) that suppresses undesired deformation of the product G, the product G in the folding operation by the rear folding plate 71.
It is possible to suppress the warp.

Further, the central support member 35 of the lift mechanism 30.
Since only a needs to be moved forward, only a relatively small force needs to be applied, and a structure for moving the central support member 35a forward by pushing with the rear folding plate 71 without providing a dedicated drive device is adopted. Is made. (8) In the stretch wrapping device 10, the product G is supported as long as possible by the central supporting member 35a that moves forward when the film F is folded by the rear folding plate 71, but the central supporting member 35a is lowered at the final stage. ing.

Then, the center support member 35a, which is in a state of moving forward from its original position at the time of descending, is guided by the guide roller 36a by using the descending inertial force of the center support member 35a. I try to return to the position. Therefore, when the lift mechanism 30 supports the product G to press the next product G against the film F, the central support member 35a appropriately supports the product G together with the left and right support members 34a and the central front-back support member 34b. It seems that you have returned to the position where you want to.

[Other Embodiments] (A) In the above embodiment, the left and right clamps 5 are provided to the operator.
Although the method of having the initial positions of the left and right directions of the 1, 52 are determined, a dedicated drive mechanism for moving the left and right clamps 51, 52 to the left and right is provided, and the width W1 of the product G and the width W3 of the film F are set. It is also possible to adopt a method of automatically setting the initial positions of the left and right clamps 51 and 52 in response to a command from the control unit 90 having data.

When a dedicated drive mechanism for moving the left and right clamps 51 and 52 to the left and right is provided in this way, the control unit 90 controls before the packaging operation or before pressing the product G against the film F in the packaging operation. And controlling the drive mechanism based on the width W1 of the product G and the width W3 of the film F,
The positions of the left and right clamps 51 and 52 are adjusted. Specifically, the control unit 90 adjusts the positions of the left and right clamps 51, 52 so that the distance W2 (see FIG. 9A) between the left and right clamps 51, 52 becomes smaller as the width W1 of the product G becomes smaller. To do. In addition, the width W3 of the film F is 5
It is used to set the maximum allowable value of the distance W2 between the 1 and 52. The control unit 90 controls the distance W between the left and right clamps 51 and 52.
Left and right clamps 51, 5 so that 2 does not exceed the maximum allowable value
Adjust the position of 2.

The positions of the left and right clamps 51 and 52 can be adjusted by the control unit 90 by adjusting the distances of the left and right clamps 51 and 52 from the left and right ends of the film F based on the width W1 of the product G. Is. Left and right clamps 51, 5
If 2 always grips the left and right edges of the film F, when the length of the product G becomes small, there is a waste of extending the portion of the film F that does not need to be wrinkled by the pre-stretching operation. By making such an adjustment, the portions near the left and right ends of the film F are not unnecessarily stretched, and a sufficient pre-stretch amount can be secured with a small amount of clamp movement.

(B) In the above-described embodiment, a method is adopted in which the operator determines the initial positions of the left and right clamps 51 and 52 in the left and right directions.
The control unit 9 determines whether the initial position adjustment of the
It is also conceivable to provide a position sensor for confirmation so that it can be judged by 0.

For example, if a plurality of position sensors capable of detecting the left and right positions of the outer ends of the left and right clamps 51 and 52 are provided, the control unit 90 causes the width W1 of the product G and the film F to be controlled.
It becomes possible to confirm whether or not the left and right clamps 51 and 52 are set at correct positions based on the data of the width W3. And, the right and left clamps 51, 52
When is not set, it is conceivable that a display (or an alarm) for notifying the operator of that fact is displayed from the control unit 90.

(C) In the above embodiment, the width W1 of the product G
The idea of adjusting the left and right positions of the left and right clamps 51 and 52 based on the above is applied to the stretch wrapping device 10 of the type that conveys the film F back and forth.
It can be similarly applied to a stretch wrapping device of a type that conveys the left and right.

(D) In the above embodiment, in the left and right folding operation, the left and right pushing members 61, 62 and the left and right folding plates 64, 65 are moved based on the control data including the information on the properties of the product G and the film F. Although the amount and the movement timing are optimized, the movement speed of the left and right pushing members 61, 62 and the left and right folding plates 64, 65 is further controlled by controlling the film pushing motor 63a and the left and right folding motor 68a with an inverter. It is also possible to optimize. Thereby, the tension of the film F can be made more appropriate.

(E) In the above embodiment, the lift mechanism 30
The central supporting member 35a is moved forward while being pushed by the rear folding plate 71.
It is also possible to adopt a configuration in which a is moved by a dedicated drive device. Further, in the above embodiment, the lift mechanism 3
0, only the central support member 35a, which is a part of the support member that supports the product G, is moved forward together with the product G. However, if the cost disadvantage is not taken into consideration, the entire support member of the lift mechanism 30 is used. It is also possible to adopt a configuration in which the vehicle can move forward.

(F) The central support member 35a of the above embodiment.
Instead of, the central support member 135 shown in FIG. 15 (a) may be used. This central support member 135 is
The support plates 135b and 135c are rotatably supported on both left and right sides of a. In addition, the support plates 135b, 1
The spring 35c is urged by a spring force (not shown) so as to return to its original state when the external force disappears even if the spring 35c is rotated back and forth.

Here, the rear folding plate 71 and the front side fixing member 7 are used.
The central support member 135 is sandwiched between the two 71, 72
When a force is applied to the support plates 135b and 135c, the support plates 135b and 135c rotate and contract (reduce) in the front-rear direction. As a result, the center support member 135 can support the product G longer than the center support member 35a.

(G) If the spring 36b shown in FIG. 15B is added to the return mechanism of the lift mechanism 30 of the above embodiment,
The operation of returning the central support member 35a to the rear more reliably is performed. The spring 36b is attached to the second base 32, and pulls the central portion of the rear link bar 35b rearward. As a result, when the first base 31 descends first and then the second base 32 descends, a backward reaction force acts from the guide roller 36a to the front link bar 35b, and the spring 36b causes a rearward reaction. A pulling force acts on the link bar 35b, and the central support member 35a returns to the original position rearward.

[0096]

According to the present invention, when the folding mechanism folds the peripheral portion of the film to the bottom side of the packaged object, the supporting portion (or a part thereof) of the lift mechanism moves while supporting the packaged object. To do. Therefore, the movement of the support portion (or a part thereof) of the lift mechanism while supporting the object to be packaged makes it possible to avoid interference between the lift mechanism and the folding mechanism at least in the initial stage of folding. As a result, when the film is folded, the state in which the object to be packaged is supported by the support portion of the lift mechanism can be maintained as long as possible. In addition, it is possible to move the packaged object in a stable state with almost no damage.

[Brief description of drawings]

FIG. 1 is a schematic side view of a stretch wrapping device.

FIG. 2 is a schematic front view of the stretch wrapping device (II-I in FIG. 1).
(I arrow view).

FIG. 3 is a schematic plan view of a stretch wrapping device.

FIG. 4 is a control block diagram of the stretch wrapping device.

FIG. 5 is a view showing movements of a first base and a second base of the lift mechanism.

FIG. 6 is a view showing movements of a first base and a second base of the lift mechanism.

FIG. 7 is a plan view of a lift mechanism.

FIG. 8 is a view on arrow VIII-VIII in FIG.

FIG. 9A is a diagram showing parameters in the initial position adjustment of the left and right clamps. (B) The figure which shows the joining part of a left clamp and a left pushing member.

FIG. 10 is a diagram showing a left-right folding operation.

FIG. 11 is a schematic plan view when the left-right folding is completed.

FIG. 12 is a diagram showing a rear folding operation.

FIG. 13 is a diagram showing a rear folding operation and a heat sealing operation.

FIG. 14 is a schematic plan view showing the post-folding operation.

FIG. 15 is a partial side view of a lift mechanism according to another embodiment.

[Explanation of symbols]

10 Stretch wrapping equipment 30 Lift mechanism 50 Heat seal and film front and back folding mechanism 31 First Base 32 second base 34b Central front and rear support member (first support portion) 35a Central support member (second support portion) 36a Guide roller (return means) 36b Spring (return means) 50 Film holding mechanism 71 Rear folding plate (rear folding member) 71a Rear folding plate moving motor 72 Front fixing member 90 Control unit 135 Central support member F film G products (packaged items)

Claims (9)

[Claims] 1. A film holding mechanism for holding a film under tension, and a lift mechanism having a support portion for supporting the bottom of an object to be packaged and for pressing the object to be packaged against the film held by the film holding mechanism. A folding mechanism that folds the peripheral portion of the film pressed against the object to be packaged by the lift mechanism to the bottom side of the object to be packaged,
The packaging device, wherein at least a part of the support portion moves while supporting the article to be packaged when the film is folded on the bottom side of the article to be packaged. 2. The folding mechanism has a rear folding member which is arranged rearward and is movable back and forth. A first moving mechanism for moving the rear folding member back and forth, and the first moving mechanism. Controlling, moving the rear side folding member forward, further comprising a control unit for moving the object to be packaged forward while folding the film to the bottom side of the object to be packaged by the rear side folding member, and At least a part of the support portion, when the film is folded to the bottom side of the packaged object by the forward movement of the rear folding member and the packaged object moves forward, while supporting the packaged object forward The packaging device according to claim 1, which moves. 3. The support portion has a first support portion and a second support portion, and the first support portion descends when the rear folding member approaches and the rear folding portion is moved. The packaging device according to claim 2, wherein interference with a member is avoided, and the second support portion moves forward while supporting the object to be packaged according to the forward movement of the rear folding member. 4. The packaging device according to claim 3, wherein the second support portion receives a force from the rear folding member and moves forward. 5. The packaging device according to claim 4, wherein the second support portion receives a force from the rear folding member and becomes smaller in the front-rear direction. 6. The packaging device according to claim 3, wherein the second support portion supports a portion including a center of a bottom portion of the article to be packaged. 7. The third support part according to claim 3, wherein after the first support part has descended, the second support part moves forward and then descends.
The packaging device according to any one of 1. 8. The lift mechanism comprises the second mechanism when the second support portion descends or after the second support portion descends.
The packaging device according to claim 7, further comprising a returning means for moving the planar position of the support portion rearward. 9. A second moving mechanism for moving at least a part of said supporting part back and forth, said control part controlling said first moving mechanism to package the film by said rear folding member. The packaging device according to claim 2, wherein the second moving mechanism is controlled to move at least a part of the support portion forward when the object to be packaged is moved forward while being folded toward the bottom side.