JPH0912004A - Stretch film wrapping machine - Google Patents

Abstract

PURPOSE: To conduct prescribed prestretching completely without a film coming off a film clamp even if the stretching quantity of the film in the width direction is large, by dividing the film clamp into four or more parts in the lengthwise direction of the film. CONSTITUTION: Both ends of a stretch film 3' delivered from a film roll 3 in the width direction are clamped and tensed by a film clamp 7, and the film 3' is pre-stretched in the width direction according to the vertical width of an object to be wrapped. The object to be wrapped is pushed up by an elevator mechanism 1 from the downside of the film 3' to cover the top of the object to be wrapped with the film 3'. The film clamp 7 is divided into four or more parts in the lengthwise direction of the film 3' to increase the clamping force of the film 3' and use only one type of film whose width is small, so it is possible to prevent the film 3' from coming off the clamp 7 even if prestretching quantity becomes large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretch film wrapping machine, and more particularly, a wrapping machine for preliminarily stretching a film in the width direction while wrapping a stretch film covering an object to be wrapped with a widthwise end portion of the stretch film. The improvement of the film clamp mechanism of the machine.

[0002]

2. Description of the Related Art In a conventional stretch film packaging machine,
In order to make a good-looking wrapping regardless of the size (size or shape) of the packaged item, insert a film clamp that holds the widthwise end of the film and stretches it at the wrapping position by sandwiching the center clamp and the center clamp. Japanese Laid-Open Patent Application No. 58-1254 discloses a method in which the clamp is divided into three left and right clamps arranged at symmetrical positions in the front-rear direction, and the timing of releasing the clamp of the film between these clamps is changed and adjusted according to the size of the object to be packaged.
No. 12 and Japanese Patent Publication No. 4-71763.

[0003]

By the way, recently, only one kind of narrow film is used by pre-stretching the film significantly in the width direction according to the longitudinal width (depth dimension) of the packaged object. A packaging machine has been developed that does not require a film switching mechanism and efficiently uses the film without waste due to the packaging structure (Japanese Patent Application No. 7-20328). In this type of packaging machine, for example, when packaging a jumbo tray having a large vertical width (depth), it is necessary to increase the amount of the pre-stretch (50% or more of the film width). . However, when the amount of pre-stretching is increased, in the above-described conventional film clamp, when the film is pre-stretched, the film may come off the clamp, and packaging may not be possible.

The present invention has been made in view of the above-mentioned problems of the packaging machine for pre-stretching and wrapping the film in the width direction, and an object thereof is to determine the amount of pre-stretching the film in the width direction. It is an object of the present invention to provide a stretch film wrapping machine that can surely perform a predetermined pre-stretch without the risk that the film will come off from the film clamp even when the value is large.

[0005]

Means for Solving the Problems The technical means taken by the present invention to achieve the above object is to stretch and stretch the stretch film unwound from a film roll by sandwiching both widthwise edges of the stretch film with film clamps. , A stretch film wrapping machine for pre-stretching the film in the width direction before pushing up the article to be packaged by pushing up the article to be packaged by an elevator mechanism from below the film and covering the upper surface of the article to be packaged, It is characterized in that the film clamp is divided into four or more along the length direction of the film. The mechanism for pre-stretching the film in the width direction is a mechanism in which both of the film clamps sandwiching both side edges in the width direction expand toward the outside in the width direction of the film, or a mechanism in which one is fixed and the other is expanded. Any of The stretch film wrapping machine described above performs the pre-stretching of the film in the width direction according to the longitudinal width of the object to be packaged before pushing up the object to be packaged by using only one kind of narrow film. .

The above-mentioned film clamp is divided into five or more odd-numbered pieces (5, 7, 9, ...) And one of them is approximately in the center of the packaging position (of the film after completion of centering). It is effective to arrange them in the center) and the other in the symmetrical positions with respect to the central clamp. In that case, the film clamp is, for example, the central clamp A.
And first left and right clamps B and B'arranged on the left and right of the central clamp A, and second left and right clamps C and C'arranged on the outside of the first left and right clamps B and B '. Divide into pieces. Further, among the film clamps divided into four or more, the length of the clamp located inside is set shorter than the length of the outermost clamp located at the front and rear ends along the length direction of the film.

Further, when the film clamp is divided into five parts, that is, the center clamp A, the first left and right clamps B and B ', and the second left and right clamps C and C', at least the center clamp A and the first left and right clamps. The clamps B and B ′ and the second left and right clamps C and C ′ are independently driven, and the timing at which the clamps release the film sandwiching is determined according to the object to be packaged. When the loading position of the product is detected, it is also possible to drive the pair of symmetrical clamps independently. Further, the structure of the film clamp described above is a type in which a pair of upper and lower flat belts, or a conventional round belt and one of a pair of upper and lower belts are pressed against the other belt via a clamp plate or the like to sandwich the film. Or, a gripper type structure that opens and closes may be used, and a pair of upper and lower flat belts,
The driving method of pinching the film with the round belt or releasing the pinching may be such that the solenoid is turned on to release the film, or the solenoid is turned off to release the film.

[0008]

According to the above means, the number of divided film clamps is four or more, which is larger than the conventional number of three. Therefore, if the total length of the clamp portion is the same, each divided film is divided by the larger number. The length of each clamp becomes shorter, and if the power source (solenoid) that operates each of the divided clamps has the same capacity as before, the clamping force per unit area will increase and the clamping that occurs across the clamp Power improves. Further, since the holding area of each clamp is small, the degree of close contact between the film and the clamp is increased, and as a result, the holding force of the entire clamp is improved. Therefore, even if the film has a large amount of pre-stretch in the width direction, the film does not come off the clamp. Further, since the number of divided film clamps is increased, finer folding control can be performed.

According to the fifth aspect of the invention, the tension adjustment can be finely performed when the object to be packaged, which requires more delicate adjustment, is small. Further, according to the configuration of claim 6, it is possible to more finely control the folding of the film according to the shape of the object to be packaged, and it is possible to make the packaging finish clean regardless of the shape of the object to be packaged.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings in which a film clamp comprises a pair of upper and lower elastic belts and a clamp plate for pressing one elastic belt against the other belt. The stretch film wrapping machine shown in FIGS. 1 and 2 is provided with a product placing section a for placing an article to be wrapped in front of a machine frame A, and the article to be wrapped placed on the article placing section a is conveyed by a conveyor B. It is transported to the elevator 1 provided inside the machine frame A. A packaging part b is provided above the elevator 1.
On the side (upstream side) of the packaging portion b, there is provided a film holding means C for holding the leading end of the film roll arranging portion 2 and the film roll 3 ′ unrolled from the film roll 3 set in the arranging portion 2. A film feed means D for sandwiching and pulling out the film held by the film holding means C and conveying it to the packaging part b is arranged close to the tip of the film holding means C, and the film holding means C and the film feed means are arranged. A cutter E that cuts the film, which is sandwiched by the film feeding means and pulled out, to a predetermined length is arranged between D and D. Further, right and left folding plates 16 and 16 ', a rear folding plate 17, and a discharge pusher 18 are disposed above the film feeding means D and above the rear folding plate 17.

Therefore, the object to be packaged placed on the elevator 1 is pushed up with respect to the film 3'extended on the packaging part b by the rise of the elevator, and the end of the film in the stretched state is After folding the left and right folding plates 16 and 16 'and the rear folding plate 17 into the bottom surface of the packaged object,
The discharge pusher 18 horizontally pushes the object to be packaged toward the heat seal portion F on the front side of the machine frame A, and the front end portion of the film 3'is folded to fold the film. Then, the end of the film folded into the bottom surface of the article to be packaged at the heat sealing section F is heat sealed to complete the packaging.

The film holding means C holds and holds both side portions of the film roll 3 set in the film roll arrangement portion 2, and is a film receiving member arranged below the film as shown in FIG. 4 and a pressing member 5 that presses the film 3'supported on the surface of the film receiving member 4 toward the film receiving member 4 side, and the holding means composed of the film receiving member 4 and the pressing member 5 has a film width. Are arranged on the left and right with an interval corresponding to the interval of, and one end of the pressing member 5 is rotatably supported so as to be openable and closable. The film receiving member 4 is fixed to an endless belt 4a driven and rotated by a motor. Then, the film receiving member 4 and the pressing member 5 are rotated by the forward rotation of the endless belt 4a (rotation in the direction of the arrow in FIG. 2).
The leading end of the film 3 ′ held by the above is moved to the starting end side end of the film feeding means D described later.
Incidentally, the film holding means C may be configured such 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 a film roll set in the film roll disposition unit 2.

The film feeding means D comprises a pair of upper and lower endless elastic belts 6 and 6'for sandwiching side edges in the width direction of the film and a lower elastic belt 6'to the upper elastic belt 6.
It is composed of a clamp plate 7 that is pressed against the side and a pressing belt 11 that is arranged so as to overlap with the upper surface of the lower elastic belt 6 ′ on the starting end side, and these are arranged in front and back with the packaging portion b interposed therebetween.
The distance is the same as that of the pair of front and rear holding means constituting the film holding means C described above. The pair of front and rear constituent members are respectively supported by the mounting frames 8 and 8 ', and the mounting frames 8 and 8'are arranged at right angles under the mounting frames 8 and 8'. Guide rod 9, 9 '
Is supported via the connecting members 10 and 10 ', the mounting frame 8'on which one feed means D1 is mounted is fixed, and the mounting frame 8'on which the other feed means D2 is mounted.
Is configured to be movable along the guide rods 9 and 9 ', and the feed means D2 on the movable side thereof has a space expanding means (not shown).
Are connected to each other so that the distance between the fixed feed means D1 and the fixed feed means D1 can be adjusted widely.

The pair of upper and lower endless elastic belts 6 and 6'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 system is a motor 12 with a speed reducer. The drive roller 6a 'around which the elastic belt 6'on the side is wound, and the drive roller 6a' is rotated.
The chain sprocket (not shown) fixed to the shaft of the drive roller 6a and the chain sprocket (not shown) fixed to the shaft of the drive roller 6a around which the upper elastic belt 6 is wound, and the power is transmitted. And the upper elastic belt 6 is also rotated.

The clamp plate 7 for pressing the lower elastic belt 6'to the upper elastic belt 6 is divided into five as shown in FIG. 3, and the five clamp plates are the central clamp plate 7a. , The first placed on the left and right of the central clamp plate 7a
The left and right clamp plates 7b and 7b 'and the second left and right clamp plates 7c and 7c' arranged outside the first left and right clamp plates 7b and 7b '. It is arranged. The five clamp plates are longer than the first left and right clamp plates 7b and 7b 'and the central clamp plate 7a which are arranged inside the second left and right clamp plates 7c and 7c' which are arranged outside. Is formed short.

Further, the clamp plate 7 divided into five parts has its central clamp plate 7a arranged substantially at the center of the packaging position (the center position of the film after the centering is completed), and the other clamp plate 7a with respect to the central clamp plate 7a. They are arranged in symmetrical positions. Further, as shown in FIG. 4, the mechanism for pressing the clamp plate 7 divided into five parts to the lower elastic belt 6 ′ and separating them from each other is such that the tip of the plunger 13 ′ of the electromagnetic solenoid 13 is fixed to a fixing member (not shown). It is connected to one end of an oscillating plate 14 which is rotatably supported, and the other end of the oscillating plate 14 is connected to the approximate center of the clamp plate 7 in the longitudinal direction.
A spring 15 is stretched on 3'and urges the plunger in a direction in which it is always pulled out. As a result, when the electromagnetic solenoid 13 is off, the spring 15 acts to clamp plate 7.
Pushes the lower elastic belt 6'to the upper elastic belt 6 side (state shown by the solid line in FIG. 4), and when the electromagnetic solenoid 13 is energized and turned on, the plunger 13 'is retracted, whereby the oscillating plate 14 becomes half. The clamp plate 7 is rotated clockwise.
Is separated from the elastic belt 6 '(state of virtual line in FIG. 4),
The pinching of the film is released. The release timing of the above-mentioned five-divided clamp plate 7 is released according to the folding order of the film, and in general, the second left and right clamp plates 7c and 7c 'arranged in the front and rear of the width direction of the film → the front and rear The left and right clamp plates 7b and 7b '→ the rear side central clamp plate 7a → the front side central clamp plate 7a are released in this order. (See Fig. 5)

Next, the operation of each part relating to packaging will be described with reference to the time chart of FIG. The control of each part of the packaging machine is performed based on the rotation angle of the cam 19 that drives the elevator 1. When the cam 19 makes one rotation, one cycle of packaging is performed. The rotation angle of the cam is detected by counting output pulses from the rotary encoder attached to the cam shaft and detecting the count value. One revolution of this cam moves the elevator up and down at the timing of (1). That is, the elevator moves up and down in the latter half of one packaging cycle, and in the first half of one packaging cycle, the object to be packaged is carried in by the conveyor B, the film is pulled out by the film feed means D, the centering and the pre-stretching are performed.

The conveyor B for carrying in the articles to be packaged is turned on / off at the timing of (2), and the film feed means D
Turns ON / OFF at the timing of (3). Although the cutter E is operated to cut the film while the film feeding means D is conveying the film, the cutter E is omitted. Therefore, the film feeding means D
During the "N" state, the film is pulled out and the cut film is centered. Although the timing at which the film feed means D is turned off differs depending on the cutting length of the film, it is turned off before the timing shown in the drawing when the cutting length is long and when the cutting length is short. The film feeding means D described above largely prestretches the film in the width direction by moving one of the feeding means D2 in the direction in which the gap is widened. The timing of the pre-stretch is shown in (4) (pre-stretch when the line is rising to the right). The amount of pre-stretch (the amount of movement of the feeding means D2) changes depending on the depth dimension of the packaged item, and the one shown in the drawing shows the maximum dimension. In this embodiment, the pre-stretching of the film is performed after the film feeding means D is turned off, and the pre-stretching is loosened during the rear folding. (Moving in the direction to reduce the interval)

(5) shows the timing of the left and right folding plates 16 and 16 ', (6) shows the timing of the rear folding plate 17, the solid line shows the standard tray type, and the dotted line shows the large tray type. The operation timing of the rear folding plate is earlier than the case. (7) shows the timing of the discharge pusher 18, the solid line shows the standard tray type, and the dotted line shows the large tray type. Note that (5), (6), and (7) perform the folding operation when the lines are rising to the right.

In (8) to (13), the clamp plate divided in five in the film feeding means D is the elastic belt 6'on the lower side.
The second left and right clamp plates 7c, 7c arranged at the front and back indicate the timing at which the film is pinched off and released.
'Is turned on at the same timing as shown in (8) and (9) respectively (when it is turned on, the clamping is released), and then the second
The first left and right clamp plates 7b and 7b 'arranged at the front and rear are turned on (ON) at the same timing as shown in (10) and (11), respectively, at least later than the timing at which the left and right clamp plates are turned on. When the pinch is released).
Then, the timing at which both the front and rear second left and right clamp plates and the first left and right clamp plates are turned on is changed in nine stages according to the object to be packaged. Further, the front and rear second left and right clamp plates and the first left and right clamp plates are turned on during the operation of the left and right folding plates 16 and 16 ', and the second left and right clamp plates 7c and 7c' and the first left and right clamp plates. Board 7b, 7b '
The later the timing when is turned on, the stronger the film tension during packaging. Therefore, the larger the width of the object to be packaged, the earlier the ON timing. (12) shows the timing when the central clamp plate 7a on the front side is turned on, and (1
3) shows the timing when the rear side central clamp plate 7a is turned on. The rear side central clamp plate 7a is turned on during the operation of the rear folding plate 17, and the timing when the rear side central clamp plate 7a is turned on depends on the object to be packaged. It is changed to the stage. The central clamp plate 7a on the front side is turned on during the operation of the discharge pusher 18, the solid line indicates the standard tray type, and the dotted line indicates the large tray type.

Therefore, the film is folded in the order of left-right->rear-> front, and the front-side folding is performed by the front folding member when the object to be packaged is discharged by the discharge pusher 18. Incidentally, since the front folding is performed after the left and right folding and the rear folding are completed, there is little influence on the film tension, and therefore the timing is only changed between the standard and large stages. The second left and right clamp plates 7c and 7c '((8) in FIG. 6), the first left and right clamp plates 7b and 7b' ((10) in FIG. 6), and the central clamp plate 7a arranged on the front side.
It turns off at 35 ° at the timing of (12 in Fig. 6).
The reason is that the film is surely released when the front side is folded. That is, when the front side is folded, the second left and right clamp plates 7c and 7c ', the first left and right clamp plates 7b and 7b', and the central clamp plate 7a arranged on the front side are folded.
Need to be released, but the second left and right clamp plates 7c and 7c 'and the first left and right clamp plates 7b arranged on the rear side
, 7b 'and the central clamp plate 7a need not be released, so they are turned off at 315 ° as shown in the timings of (9), (11) and (13). Turning it off earlier has the advantage of saving power consumption.

In the above-mentioned embodiment, the film feeding means D is used.
It is an example in which the place for sandwiching the film in 5 is divided into 5, but the present invention may be divided into 4 or more. Further, although the film clamping is released by the structure in which the electromagnetic solenoid is turned on and released, it goes without saying that the film may be released by turning off the electromagnetic solenoid. Further, in the above-mentioned embodiment, the five-divided clamp plates equipped in the film feed means D are the timings at which the clamp plates at the symmetrical positions are paired and released at the same time. This is because it is premised that the items are delivered so as to coincide with the center. However, it is also possible to independently drive the clamp plates at the bilaterally symmetrical positions by detecting the carry-in position of the packaged object.

[0023]

The stretch film wrapping machine according to the present invention has the structure described in claims 1 and 2, and the film holding force is improved as compared with the conventional three-division. As a result, even if the amount of pre-stretching is increased, the film does not come off from the member that holds and conveys the film, and it is possible to reliably perform the predetermined pre-stretching. Also, since the number of divisions has increased compared to the past, by appropriately adjusting the release timing of the members that sandwich these films, it is possible to perform finer folding control, improve the finish of packaging, and The range can be expanded. When the number of divisions is set as claimed in claims 3, 4 and 6, the center of the film is clamped, and symmetrical positions can be clamped with the center as a boundary. The parts can be folded in a good balance. Further, according to the configuration of the fifth aspect, it is possible to obtain an effect that the film tension can be finely adjusted even for a small object to be packaged that requires delicate adjustment. In addition, according to the configuration of claim 6, it is possible to finely control the folding of the film according to the shape of the object to be packaged, and the packaging finish can be made clear regardless of the shape of the object to be packaged.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional side view showing an outline of a stretch film packaging machine according to the present invention.

2 is a vertical front view of FIG. 1. FIG.

FIG. 3 is a schematic plan view showing the positional relationship between the film feeding means, the left and right folding plates, and the rear folding plate.

FIG. 4 is a partial enlarged cross-sectional view showing the structure of a clamp plate in the film feeding means.

FIG. 5 is an explanatory view showing a releasing order of the five-divided clamp plate in the film feeding means.

FIG. 6 is a time chart showing the operation of each unit regarding packaging.

[Explanation of symbols]

1 ... Elevator 3 ... Film roll 6, 6 '... Upper and lower elastic belts 7 ... Clamp plate 7a ... Central clamp plate 7b, 7b' ... First left / right clamp plate 7c, 7c '... Second left / right clamp plate D ... Film Clamp (Film feed means)

Claims (6)

[Claims] 1. A stretch film unwound from a film roll is stretched by sandwiching both side edges in the width direction with film clamps, and an object to be packaged is pushed up from the lower side of the film by an elevator mechanism to provide an upper surface of the object to be packaged. In the stretch film wrapping machine which covers the film with a film and prestretches the film in the width direction before pushing up the object to be packaged, the film clamp is divided into four or more along the length direction of the film. Stretch film packaging machine. 2. The stretch film packing machine uses only one kind of narrow film by pre-stretching the film in the width direction according to the longitudinal width of the packaged object before pushing up the packaged object. The stretch film packaging machine according to claim 1, wherein the stretch film packaging machine is used for packaging. 3. The film clamp is divided into five or more odd-numbered ones, one of which is arranged substantially in the center of the packaging position, and the other is arranged in a symmetrical position with respect to the center clamp. The stretch film packaging machine according to claim 1 or 2, wherein the stretch film packaging machine is provided. 4. The film clamp includes a center clamp A, first left and right clamps B and B ′ arranged on the left and right of the center clamp A, and the first left and right clamps B and B ′.
The stretch film wrapping machine according to claim 3, wherein the stretch film wrapping machine is divided into five second left and right clamps C, C'arranged outside. 5. In the film clamp having five or more divisions, the length of a clamp disposed inside the clamp is shorter than the length of the clamp located at the front and rear ends along the length direction of the film. The stretch film packaging machine according to claim 3 or 4. 6. At least the central clamp A, first left and right clamps B, B ', and second left and right clamps C,
5. The stretch film wrapping machine according to claim 4, wherein C ′ are driven independently of each other, and the timings at which the clamps release the holding of the film are determined according to the object to be wrapped.