JP2929972B2 - Stretch film packaging machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretch film wrapping machine, and more particularly, to a wrapping method in which a widthwise end of a stretched film covering an object to be wrapped is sandwiched by a film clamp, and the film is prestretched in a widthwise direction and wrapped. The improvement of the film clamp mechanism of the machine.

[0002]

2. Description of the Related Art In a conventional stretch film packaging machine,
A film clamp that stretches the film in the packaging position by holding the widthwise end of the film is sandwiched between the center clamp and the center clamp in order to pack the package irrespective of the size (size and shape) of the packaged object. Japanese Patent Application Laid-Open No. 58-1254 discloses a device in which right and left clamps arranged at symmetrical positions are divided into three, and the timing of releasing the clamp of the film by these clamps is changed and adjusted in accordance with the size of the article to be packaged.
No. 12 and Japanese Patent Publication No. 4-71763.

[0003]

By the way, recently, by pre-stretching the film largely in the width direction according to the vertical width (depth dimension) of the packaged object, only one kind of narrow film is used. A packaging machine has been developed in which a film switching mechanism is not required by a configuration for performing packaging, and a film is used efficiently and without waste (Japanese Patent Application No. 7-20328). In this type of wrapping machine, for example, when wrapping a large length (depth dimension) such as a jumbo tray, it is necessary to increase the amount of the pre-stretch (50% or more of the film width). . However, when the amount of pre-stretch 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 performed.

The present invention has been made in view of the above-mentioned problems of a packaging machine for pre-stretching and wrapping a film in the width direction thereof. It is an object of the present invention to provide a stretch film wrapping machine capable of performing a predetermined pre-stretch without any risk of the film coming off from the film clamp even when the film is large.

[0005]

In order to achieve the above-mentioned object, the present invention provides a technical means that a film clamp is provided by clamping both side edges in the width direction of a stretched film cut out to a predetermined length from a film roll. The film is stretched by pushing up the packaged object from the lower side of the film by an elevator mechanism, and the upper surface of the packaged object is covered with a film. In a stretch film wrapping machine in which the distance between the film clamps is expanded according to the vertical width of the packaged object to pre-stretch the film in the width direction by an amount corresponding to the vertical width of the packaged object, It is characterized in that it is divided into four or more along the length direction. The mechanism for pre-stretching the film in the width direction is a mechanism in which both film clamps sandwiching both side edges in the width direction expand outward toward the width direction of the film, or a mechanism in which one is fixed and the other is expanded. Either may be used. The above stretch film packaging machine performs packaging using only one kind of narrow film by pre-stretching the film in the width direction according to the vertical width of the packaged object before pushing up the packaged object. .

The above-mentioned film clamp is divided into an odd number (5, 7, 9,...) Of 5 or more, and one of them is substantially in the center of the packaging position (the center of the film after completion of centering). It is effective to arrange it at the center) and to arrange the others at symmetrical positions with respect to the center clamp. In that case, the film clamp is, for example, a center clamp A
And five first left and right clamps B and B ′ disposed on the left and right of the center clamp A and second left and right clamps C and C ′ disposed outside the first left and right clamps B and B ′. Divide into pieces. Further, of the four or more divided film clamps, the length of the clamp located on the inner side is shorter than the length of the outermost clamp located on the front and rear ends along the length direction of the film.

Further, when the film clamp is divided into a center clamp A, first right and left clamps B and B ', and second left and right clamps C and C', at least the center clamp A, the first left and right clamps are used. The clamps B and B 'and the second left and right clamps C and C' are driven independently of each other, and the timing at which these clamps release the holding of the film is determined according to the packaged object. In the case where the carry-in position of the product is detected, the pair of symmetrical clamps can be independently driven. The above-described film clamp structure is of 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 clamp the film. Or a structure such as a gripper type that opens and closes, and a pair of upper and lower flat belts,
The driving method for holding the film with the round belt and releasing the holding may be such that the film is released when the solenoid is turned on, or is released when the solenoid is turned off.

[0008]

According to the above means, the number of divided film clamps is set to four or more, which is greater than the conventional three, so that if the total length of the clamp portion is the same, the larger the number of divisions, the larger the number of divisions. If the length of each clamp is shortened and the power source (solenoid) for operating each of the divided clamps is the same as the conventional one, the clamping force per unit area will increase, and the clamping generated in the entire clamp Power improves. Further, since the clamping area of each clamp is small, the degree of close contact between the film and the clamp is increased, and as a result, the clamping force of the entire clamp is improved. Therefore, even if the pre-stretch amount in the width direction of the film is large, the film does not come off the clamp. Further, since the number of divided film clamps is increased, finer folding control can be performed.

Further, according to the structure of the fifth aspect, the tension adjustment can be finely performed when the object to be packaged which requires more fine adjustment is small. Furthermore, according to the configuration of the sixth aspect, it is possible to control the folding of the film more finely according to the shape of the article to be packaged, and to make the packaging finish beautiful regardless of the shape of the article 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 portion a on which a packaged product is placed in front of a machine frame A, and the packaged product placed on the product placing portion 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, a film roll disposition portion 2 and a film holding means C for holding a leading end portion of a film 3 ′ unwound from a film roll 3 set in the disposition portion 2 are provided. A film feed means D for holding and pulling out the film held by the film holding means C and transporting the film 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 A cutter E that cuts the film that has been pulled out and held by the film feed means into a predetermined length is disposed between the film E and the cutter D. Above the film feed means D, left and right folding plates 16 and 16 ', a rear folding plate 17, and a discharge pusher 18 located above the rear folding plate 17 are provided.

Therefore, the article to be packaged placed on the elevator 1 is pushed up against the film 3 'spread on the packaging section b by raising the elevator, and the end of the film in the stretched state is After folding into the bottom of the package by the left and right folding plates 16, 16 'and the rear folding plate 17,
The front end of the film 3 'is folded while the package is horizontally moved by the discharge pusher 18 toward the heat seal portion F in front of the machine frame A, and the film is folded. 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 sides of the film roll 3 set in the film roll placement section 2, and is a film receiving member arranged below the film as shown in FIG. 4 and a pressing member 5 for pressing the film 3 ′ supported on the surface of the film receiving member 4 against the film receiving member 4. The holding means composed of the film receiving member 4 and the pressing member 5 forms a film width. The pressing member 5 is pivotally supported at one end and is rotatably opened and closed. The film receiving member 4 is fixed to an endless belt 4a driven and rotated by a motor. Then, the forward rotation of the endless belt 4a (rotation in the direction of the arrow in FIG. 2) causes the film receiving member 4 and the pressing member 5 to rotate.
Is moved to the starting end of the film feed 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 includes a pair of upper and lower endless elastic belts 6 and 6 ′ and a lower elastic belt 6 ′ which sandwich a lateral end portion of the film in the width direction.
The clamp plate 7 is pressed against the side and the presser belt 11 is superimposed on the upper surface of the lower end of the elastic belt 6 'on the starting end side.
The interval is the same as that of a pair of front and rear holding units constituting the film holding unit C described above. The pair of front and rear components are supported by mounting frames 8, 8 ', respectively, and the mounting frames 8, 8' are arranged at right angles below the mounting frames 8, 8 '. Guide rod 9, 9 '
The mounting frame 8 'to which one feed means D1 is mounted is fixed, and the mounting frame 8' to which the other feed means D2 is mounted is fixed.
Is configured to be movable along the guide rods 9 and 9 ', and the distance extending means (not shown) is provided on the movable feeding means D2.
Are connected to each other so that the distance from the fixed-side feed means D1 can be adjusted.

A 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 held and transported. Roller 6a 'around which the elastic belt 6' is wound, and the driving roller 6a '
The power is transmitted by winding the chain over a chain sprocket (not shown) fixed to the shaft of the drive roller 6a and a chain sprocket (not shown) fixed to the shaft of the drive roller 6a around which the upper elastic belt 6 is wound. And the upper elastic belt 6 is also rotated.

The clamp plate 7 for pressing the lower elastic belt 6 'against the upper elastic belt 6 is divided into five, as shown in FIG. 3, and the five clamp plates are formed by a central clamp plate 7a. , The first clamps disposed on the left and right of the central clamp plate 7a.
Right and left clamp plates 7b and 7b 'and second left and right clamp plates 7c and 7c' disposed outside the first left and right clamp plates 7b and 7b '. Are located. The five clamp plates are longer than the lengths of the first left and right clamp plates 7b, 7b 'and the central clamp plate 7a, which are disposed inside the second left and right clamp plates 7c, 7c' disposed outside. Are formed short.

Further, the clamp plate 7 divided into five parts has the center clamp plate 7a disposed substantially at the center of the packaging position (the center position of the film after the centering is completed), and the other clamp plates 7a are positioned with respect to the center clamp plate 7a. They are arranged at symmetrical positions. Further, the mechanism for pressing the five-divided clamp plate 7 against the lower elastic belt 6 'and separating the same from each other is as shown in FIG. 4 by applying the tip of the plunger 13' of the electromagnetic solenoid 13 to a fixing member (not shown). The other end of the swinging plate 14 is connected to substantially the center of the clamp plate 7 in the longitudinal direction, and the plunger 1
A spring 15 is stretched at 3 'to urge the plunger in a direction of always being pulled out. As a result, when the electromagnetic solenoid 13 is turned off, the clamp plate 7 is actuated by the action of the spring 15.
Presses the lower elastic belt 6 'against the upper elastic belt 6 (the state shown by the solid line in FIG. 4). The clamp plate 7 is rotated clockwise to
Is separated from the elastic belt 6 '(the state of the imaginary line in FIG. 4),
The film is released. The release timing of the above-mentioned five divided clamp plates 7 is released in accordance with the order of folding of the film, and in general, the second left and right clamp plates 7c, 7c 'arranged before and after in the width direction of the film → The left and right clamp plates 7b, 7b 'are released in the order of the rear central clamp plate 7a and the front central clamp plate 7a. (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 for driving the elevator 1, and 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 a rotary encoder attached to the cam shaft and detecting the count value. The elevator moves up and down at the timing of (1) by one rotation of the cam. 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 conveyor B carries in the articles to be packaged, and the film feeding means D pulls out the film, centering, and pre-stretch.

The conveyor B for carrying in the package is turned on / off at the timing (2), and the film feeding means D
Turns ON / OFF at the timing of (3). Although the film is cut by operating the cutter E during the film transport of the film feeding means D, the cutter E is omitted. Therefore, if the film feed means D is "O
During the "N" state, the film is being pulled out and the cut film is centered. The timing at which the film feed means D is turned off varies depending on the cut length of the film. However, in the case shown, the cut length is long, and when the cut length is short, the film feed means D is turned off before the shown timing. The film feeding means D described above largely pre-stretches the film in the width direction by moving one of the feeding means D2 largely in the direction of expanding the interval. The timing of the pre-stretch is shown in (4) (the pre-stretch is performed when the line rises to the right). The amount of pre-stretch (the amount of movement of the feeding means D2) changes according to the depth of the packaged object, and the illustrated one shows the case of the maximum size. In this embodiment, the pre-stretching of the film is performed after the film feeding means D is turned off, and the pre-stretch is loosened in the middle of the backward folding. (Moved in the direction to narrow the gap)

(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 indicates the standard tray type, and the dotted line indicates the large tray type. The operation timing of the rear folding plate is advanced earlier than in the case. (7) shows the timing of the discharge pusher 18, wherein the solid line represents the standard tray type and the dotted line represents the large tray type. In addition, (5), (6), and (7) perform the folding operation at the time of the line rising to the right, respectively.

(8) to (13) show that the clamp plate divided into five in the film feed means D is the lower elastic belt 6 '.
Shows the timing to release the film holding by separating from the second clamp plate, and the second left and right clamp plates 7c, 7c arranged before and after
Are turned ON at the same timing (when ON, the pinching is released) as shown by (8) and (9), respectively.
The first left and right clamp plates 7b and 7b 'arranged before and after the timing of turning on (ON) of the left and right clamp plates are turned on (ON) at the same timing as shown by (10) and (11), respectively. When the pinch is released).
The timing at which the second left and right clamp plates before and after and the first left and right clamp plates are turned ON in accordance with the article to be packaged is changed to nine stages. Further, the front and rear second left and right clamp plates and the first left and right clamp plate 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 plate. Plates 7b, 7b '
The later the ON timing is, the stronger the film tension at the time of packaging. Therefore, the ON timing is set earlier as the width of the packaged object increases. (12) shows the timing at which the front center clamp plate 7a is turned on.
3) shows the timing at which the rear center clamp plate 7a is turned on. The rear center clamp plate 7a is turned on during the operation of the rear folding plate 17, and the timing at which it is turned on depends on the package. Changed to a stage. The front center clamp plate 7a is turned on during the operation of the discharge pusher 18, and the solid line indicates the standard tray type and the dotted line indicates the large tray type.

Therefore, the folding of the film is performed in the order of left, right, rear and front, and the folding on the front side is folded by the front folding member when the packaged object is discharged by the discharge pusher 18. Since the front folding is performed after the left and right folding and the subsequent folding are completed, the timing is only changed in two stages of the standard and the large size since the influence on the film tension is small. The second left and right clamp plates 7c, 7c '(FIG. 6 (8)), the first left and right clamp plates 7b, 7b' (FIG. 6 (10)), and the central clamp plate 7a are arranged on the front side.
OFF at 35 ° at the timing of (12) in FIG.
This is to ensure release of the film when the front side is folded. That is, at the time of folding in the front side, the second left and right clamp plates 7c and 7c ', the first left and right clamp plates 7b and 7b' and the center clamp plate 7a arranged on the front side.
Must be released, but the second left and right clamp plates 7c, 7c ', the first left and right clamp plates 7b
, 7b 'and the center clamp plate 7a do not need to be released, and are therefore turned off at 315 ° as shown in the timings (9), (11) and (13). Turning OFF earlier has the advantage of saving power consumption.

In the above-described embodiment, the film feeding means D
Is an example in which the portion for holding the film is divided into five parts, but the present invention may be any part as long as it is divided into four or more parts. In addition, although the structure in which the electromagnetic solenoid is turned on and released to release the film sandwiching is shown, it goes without saying that the film may be released when the electromagnetic solenoid is turned off. Further, in the above-described embodiment, the five-divided clamp plates provided in the film feeding means D are released at the same time by the pair of symmetrical clamp plates being released at the same time. This is because it is assumed that the goods are carried in such a way that they coincide with the center. However, it is conceivable that the clamp plates at the symmetrical positions are independently driven at different timings by detecting the carry-in position of the article to be packaged.

[0023]

According to the stretch film packaging machine according to the present invention, the holding force of the film is improved as compared with the conventional three-division structure. Thus, even if the amount of pre-stretch is increased, the film does not come off from the member for nipping and transporting the film, and the predetermined pre-stretch can be performed reliably. In addition, since the number of divisions has increased compared to the prior art, by appropriately adjusting the release timing of the members that sandwich these films, finer folding control can be performed, and the finish of the packaging can be improved, and the products that can be packaged can be improved. The range can be expanded. When the number of divisions is set as in claims 3, 4, and 6, the center of the film can be sandwiched and the symmetrical position can be sandwiched around the center, so that the film is stretched and the film ends with respect to the packaged object. The folding of the part can be performed in a well-balanced manner. Further, according to the configuration of the fifth aspect, it is possible to obtain the effect that the adjustment of the film tension can be finely performed even for a small package that requires fine adjustment. Further, according to the configuration of the sixth aspect, it is possible to finely control the folding of the film in accordance with the shape of the article to be packaged, and it is possible to make the packaging finish beautiful regardless of the shape of the article to be packaged.

[Brief description of the drawings]

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

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

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

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

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

FIG. 6 is a time chart showing the operation of each part relating to packaging.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Elevator 3 ... Film roll 6, 6 '... Upper and lower elastic belts 7 ... Clamp plate 7a ... Central clamp plate 7b, 7b' ... 1st right and left clamp plate 7c, 7c '... 2nd left and right clamp plate D ... Film Clamp (film feeding means)

Claims (6)

(57) [Claims] 1. A stretch film which has been unwound from a film roll and cut to a predetermined length is stretched by sandwiching both side edges in the width direction of the stretch film with a film clamp, and pushing up a packaged object from below the film by an elevator mechanism. By stretching the film, covering the upper surface of the packaged object with the film, and further expanding the interval between the film clamps according to the vertical width of the packaged object before pushing up the packaged object, thereby making the film wider. A stretch film wrapping machine for pre-stretching an amount according to the longitudinal width of an object to be wrapped, wherein the film clamp is divided into four or more pieces along the length direction of the film. 2. The stretch film packaging machine uses only one type of narrow film by pre-stretching the film in the width direction according to the vertical width of the packaged object before pushing up the packaged object. The stretch film wrapping machine according to claim 1, wherein the wrapping is performed. 3. The film clamp according to claim 1, wherein said film clamp is divided into an odd number of five or more, one of which is disposed substantially at the center of the packaging position, and the other is disposed at a symmetrical position with respect to said central clamp. The stretch film packaging machine according to claim 1 or 2, wherein 4. The film clamp includes a center clamp A, first left and right clamps B and B ′ disposed on the left and right of the center clamp A, and the first left and right clamps B and B ′.
4. The stretch film packaging machine according to claim 3, wherein said stretch film packaging machine is divided into five second right and left clamps C and C 'disposed outside the stretcher. 5. The film clamp having five or more divisions, wherein a length of a clamp disposed inside the film clamp is shorter than a length of a clamp located at front and rear ends along a length direction of the film. The stretch film packaging machine according to claim 3 or 4. 6. At least the center clamp A, the first left and right clamps B and B ′, and the second left and right clamps C and
5. The stretch film packaging machine according to claim 4, wherein C's are driven independently of each other, and the timing at which the clamps release the film is determined in accordance with an object to be packaged.