JP2907098B2 - 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 packaging machine, and more particularly, to a stretch film stretched at a predetermined packaging position (hereinafter simply referred to as a film).
In addition, the present invention relates to a so-called elevator-type packaging machine in which a product is placed on an elevator head, and is lifted up from the lower side of the film by raising the elevator to cover and package the upper surface of the product with the film.

[0002]

2. Description of the Related Art In a so-called elevator type stretch film wrapping machine, a product (packaged object) is pushed up by an elevator from below a film stretched at a predetermined wrapping position (packing portion), and the upper surface of the product is filmed. After that, the end of the film is folded into the bottom of the product to complete the packaging. By the way, in the above-mentioned stretch film packaging machine, the size of the elevator head which pushes up the product from below with respect to the film stretched at the predetermined packaging position is limited to the maximum size product that can be packed due to mechanical limitations. It is configured in a size corresponding to. For this reason, there is no problem when the size of the product to be wrapped is approximately the same size as the size of the elevator head, but when the size of the product is several times smaller than the size of the elevator head, this is not a problem. There is a problem that the film covering the periphery of the product is easily loosened or the like, and it is difficult to obtain a clean packaging finish.
Therefore, from the viewpoint of the packaging finish, it is desirable that the size of the elevator head is set to a size according to the product to be packaged.

To solve the above-mentioned problem, an elevator head is divided into a central head and side heads arranged on the left and right sides of the central head.
Change the size of the elevator head according to the size of the product by selecting whether to use the side head that constitutes the elevator head according to the width of the product to be packaged or the length of the film A packaging machine capable of performing the above has been proposed (Japanese Patent Publication No. 5-58967), and some of the packaging machines have been put to practical use. Instead of selecting the head to be used recently, the interval between the head elements constituting the elevator head is automatically changed according to the vertical width of the product to be packaged and the film width to be used By doing so, a packaging machine capable of gradually changing the size of the elevator head has been developed and proposed. (JP-A-7-232706)

[0004]

However, in the former configuration described above, the size of the elevator head can only be selected from two types, large and small, which are predetermined, and the range of change is small. It is hard to say satisfactory. The latter case has the advantage that the variable range of the size of the elevator head can be freely variably adjusted as long as the variable range of the size of the elevator head is within a predetermined range. There is a restriction that it must be completed before carrying in. Furthermore, in the embodiment equipped with the configuration, two types of film rolls having different widths are set in the packaging machine, and the film roll to be used can be automatically selected according to the size of the product. Although it is configured, it takes a considerable processing time to automatically select a film to be used, and the interval between the head elements is adjusted using this time. Therefore, apparently, no dead time is caused by adjusting the interval between the head elements.

However, as in the stretch film packaging machine developed and proposed by the present applicant, one kind of narrow film roll is set and the film is prestretched so that the film roll does not need to be replaced. In the case where the above method is applied to the packaging machine configured as described above, it is necessary to devise so that the time for adjusting the interval between the head elements does not become a waste time. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and an object of the present invention is to adjust the size of an elevator head for mounting a product without wasting time. It is to provide a packaging machine which can be used.

[0006]

Means for Solving the Problems] technical measure taken by the present invention for achieving the above object, the width direction of the film both
Wraps the film cut to the specified length while holding the side end
Transporting the film to the position
Retched and stretched to the packaging position, this is the elevator head
The goods brought in above are raised by raising the elevator
Push up the film from below to cover the top of the product
The product is lifted in the stretch film packaging machine
Loading means for loading on the head, and width direction of the film
A pair of fills that hold both sides of the
The distance between the film transfer means and the pair of film transfer means.
Stretch the film in the width direction by stretching
Tension means, and a plurality of heads constituting the elevator head.
The head of the elevator head that adjusts the distance between the head elements
Variable size means and the loading of goods by the loading means
A vertical width detecting means for detecting the vertical width of the product on the above,
The film width is increased based on the detection result of the vertical width detecting means.
Decision to determine variable amount of tension and head size variable means
Means, based on the determination result of the determination means,
Before being loaded onto the head,
When the drive control is performed to complete the head size adjustment,
At least the product is lifted by raising the elevator head.
Before the surface comes into contact with the film,
Control means for controlling the drive to end the expansion of the film width . The variable amount of the head size changing means can be determined automatically according to the size of the product conveyed by the carrying-in means, or manually by inputting the product number of the product, inputting the tray type, or the like.

The direction in which the distance between the head elements is adjusted may be either the depth (vertical width) direction of the direction in which the product is fed or the width direction orthogonal to the depth direction, or both the depth and width directions are adjusted. You may do so. If the direction of the width adjustment is either the depth direction or the width, the width adjustment in the remaining direction is performed by dividing the head element into a central portion and left and right portions, or a central portion and front and rear portions, and using the head element to be used. The head size may be adjusted (changed) by selecting. (See Japanese Patent Publication No. 5-58967) The head size changing means for adjusting the distance between the head elements can be any as long as it can reciprocate the support member on which the head elements are attached in a certain direction linearly. As a method, a belt or a chain that converts the rotation of a motor into a linear motion, an air cylinder or a ball screw mechanism that reciprocates linearly, and a wire and a spring as disclosed in JP-A-7-232706 are used, and the wire is used as a motor. Any method may be used, such as a winding method.

[0008] The variable amount of the head size variable means is determined until the goods are carried into the elevator head by the carry-in means, and the variable amount is automatically determined according to the size of the goods. This is performed by a vertical width detecting means for detecting the vertical width (depth dimension) of the product during the loading of the product by the loading means, and a determining means for determining a variable amount of the head size variable means based on the detection result of the vertical width detecting means. be able to. In addition, the vertical width detecting means has a sensor arranged near the conveying path side of the loading means, and the time from when the sensor detects the front end of the conveyed product to when the rear end is detected, and when the conveying means moves the conveying means. It can be appropriately selected from a method of calculating and calculating from the speed or a length detection method adopted today.

When the elevator is lowered, the head size is returned to a predetermined initial size. The initial size may be a minimum size, a maximum size, or an intermediate size .

[0010] With the above configuration, the head size adjustment in the elevator is performed in parallel while the goods are being carried in by the carry-in means, so that the head size adjustment time is not wasted. Then, determines the amount of expansion of the variable volume and the film width of the head size according to the vertical width of the product to be detected by the transportable inlet developing, adjustment of the head size product is loaded onto the elevator head based on the determination result The expansion of the film width is completed before the elevator on which the goods are loaded is raised at least before the upper surface of the goods comes into contact with the film, and packaging is performed.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The stretch film wrapping machine shown in FIGS. 1 and 2 is provided with a product placing portion (measuring portion) a for placing a product (packaged object) in front of the machine frame A, and placed on the product placing portion a. The product is transported by the pusher conveyor B to the elevator 1 provided inside the machine frame A. A sensor S1 for measuring the width of the product placed on the product placing portion a is disposed in front of the product placing portion, and the depth of the product conveyed by the pusher conveyor B is located near the pusher conveyor B. Sensors S2 and S3 for measuring the height dimensions are provided. A packaging part b is provided above the elevator 1, and a film 3 unwound from a film roll disposition part 2 and a film roll 3 set in the disposition part 2 on the side (right side in FIG. 2) of the packaging part b. The film holding means C for holding the leading end of the film holding means C is provided. The film transferring means D for holding and pulling out the leading end of the film held by the film holding means C and transferring it to the packaging part b is provided by the film holding means C. The film 3 ′ is disposed close to the leading end, and is held between the film holding means C and the film transporting means D and held and pulled out by the film transporting means D.
The cutter E which cuts to a predetermined length is arrange | positioned.
Above the film transport means D, a left and right folding plate 4,
4 ′, the rear folding plate 5, and a discharge pusher 6 disposed above the rear folding plate 5.

Therefore, the product placed on the elevator 1 is pushed up with respect to the film 3 'spread on the wrapping part b by the lift of the elevator 1, and the end of the film in the stretched state is After the product is folded into the bottom of the product by the left and right folding plates 4 and 4 'and the rear folding plate 5, the product is horizontally pushed by the discharge pusher 6 toward the discharge portion (heat seal portion) 7 on the front side of the machine frame A. The front end of the film 3 'is folded into the bottom of the product by the front folding roller 7' to complete the folding of the film. If the stretch wrapping machine is a weighing / packing price maker, a label is attached during transfer by the discharge pusher 6.

The film holding means C comprises a film 3 'of the film roll 3 set in the film roll placement section 2.
As shown in FIG. 2, a film receiving plate 8 erected and fixed over an endless belt 8 which is located below the film and arranged in parallel at a predetermined interval in the front-rear direction as shown in FIG. A holding plate 9 of the same shape for holding the film supported on the surface of the film receiving plate 8 ′ with the film receiving plate 8 ′, and a holding roller 10 attached to the film receiving plate 8 ′. , And the holding plate 9 is
, Is vertically slidably supported inside a protective cover 11 which is rotatable to open and close, and engages with a film receiving plate 8 ′ which is fixedly mounted on the endless belt 8 and slides up and down together. The end of the film 3 ′ sandwiched and held between the film receiving plate 8 ′ and the holding plate 9 can be transferred to the film transfer means D.

Further, the endless belt 8 is wound around a pulley fixed to a rotating shaft of a motor 13, a pulley 15 coaxial with a feed roller (film supply roller) 14, and a driven pulley 16, The drive of the motor 13 causes the endless belt 8 to move up and down (forward / reverse rotation) along the moving direction of the film. The drive of the feeding roller 14 for pulling out and supplying the film of the film roll 3 to the film holding means C is connected via a pulley to a drive system of a film transport means D described later, and an intermediate transmission pulley (not shown). In (2), a brake and a clutch are used, and the driving and stopping of the feeding roller are controlled separately from the film holding means C, and are controlled so as to stop simultaneously with the operation of the cutter for cutting the film. Furthermore, the film receiving plate 8 'constituting the film holding means C
A plurality of notches are formed at the upper end of the holding plate 9 with reference to one end in the width direction so as to be able to correspond to film rolls having different film widths. Is configured to be delivered. The film holding means C
It is also possible to arbitrarily configure one or both of the holding means in the width direction in accordance with the film width so as to correspond to a film roll set in the film roll disposition portion 2 by being divided into two in the width direction.

The film transport means D comprises a pair of upper and lower endless elastic belts 18, which sandwich side edges in the width direction of the film.
18 ', a clamp plate 19 for pressing the lower elastic belt 18' against the upper elastic belt 18 side, and the starting end side of the lower elastic belt 18 'is inclined downward toward the film holding means C. And a pressing belt 20 which is disposed so as to be superimposed on the upper surface of the downwardly inclined starting end and whose opening and closing can be freely moved at the leading end thereof, which sandwiches the packaging portion b as shown in FIG. It is arranged at a position for holding the side end of the film 3 ′ pulled out from the film roll 3 back and forth. The pair of front and rear components are supported by mounting frames 21 and 21 ′, and the mounting frames 21 and 21 ′ are disposed at right angles to the lower sides of the mounting frames 21 and 21 ′.
The mounting frame 21 which is supported by the guide rods 22 and 22 'of the book via connecting members 23 and 23', and to which one of the film transport means D1 is mounted, is fixed and the mounting frame to which the other film transport means D2 is mounted. 21 'is constructed so as to be movable along the guide rods 22, 22', and the film transport means D2 on its movable side.
Is connected to a distance extending means (not shown) so that the distance from the fixed-side film transport means D1 can be adjusted.

A pair of upper and lower endless elastic belts 18 and 18 'constituting the above-mentioned film transfer means are driven and rotated in the same direction so as to pinch and convey the film. The drive roller 18'a around which the lower elastic belt 18 'is wound rotates, and a chain sprocket (not shown) fixed to the shaft of the drive roller and the upper elastic belt 18 are wound. The power is transmitted by winding the chain around a chain sprocket (not shown) fixed to the shaft of the drive roller 18a, and the upper elastic belt
18 is also configured to rotate. Further, the clamp plate 19 for pressing the lower elastic belt 18 'against the upper elastic belt 18 is not limited to the illustrated three-division but may be divided into four or more, and such a clamp plate can be uniformly transported and expanded. It is arranged so as to be symmetrical about the center of the packaging part b.

The cutter E for cutting the film drawn by the operation of the film transport means D and the feed roller 14 into a predetermined length is controlled substantially at right angles to the film 3 'by a control means constituted by an electromagnetic solenoid 25. The film 3 ′ is configured to be protruded and retracted, and the film 3 ′ is configured to be cut by controlling the power supply to the electromagnetic solenoid 25.

The film pulled out by a predetermined length by the above-mentioned film transfer means D and cut by the cutter E is stretched on the packaging part b, and the elevator 1 which pushes up the commodity from below on the stretched film. Is configured such that the head size can be variably adjusted according to the size of the product into which the elevator head F above is carried.
Hereinafter, the configuration of the elevator head F will be described with reference to FIGS. The elevator head F includes a fixed head element 101 having a rectangular planar shape and a movable head element including two round rods disposed in front of the fixed head element 101, which are disposed near the product loading section. And a fixed head element 101 and a movable head element 102
Are provided in five rows in the width direction so as to sandwich the pusher belt of the pusher conveyor. The fixed head element 101 and the movable head element 102 are respectively composed of three central rows 101a, 102a and left and right head elements 101b, 101c, 102b,
The central three rows 101a and 102a may be moved up and down depending on the size of the goods to be carried in, or the central three rows 101a and 102a and the left and right outer 101b, 101c and 102.
All of b and 102c are configured to move up and down integrally (see FIG. 7). The vertical movement of the central three rows and the whole (5
Switching of vertical movement of row) has already been proposed
As in the configuration shown in Japanese Patent Application Laid-Open No. 58967, when the three rows at the center and the left and right sides have separate upper and lower structures, and both upper and lower structures are connected by the electromagnetic clutch 26 and the clutch 26 is turned on, FIG. As shown in a), all of the fixed head element 101 and the movable head element 102 in the five rows in the width direction are moved up and down,
When the electromagnetic clutch 26 is turned off, only the fixed head element 101 and the movable head element 102 in the central three rows in the width direction are moved up and down as shown in FIG. 7B. That is, the rotating shaft 61
A front lever 62 and a rear lever 63, one ends of which are connected via the electromagnetic clutch 26, are arranged in parallel, and the rear lever 63 swings with the rotation of the cam 50. The swing of the rear lever 63 is transmitted to the front lever 62 via the rotation shaft 61 and the electromagnetic clutch 26. Therefore, when the electromagnetic clutch 26 is ON, the front lever 62 and the rear lever 62
When the electromagnetic clutch 26 is OFF, only the rear lever 63 performs the swing operation. Rear lever 63
Is a lever for moving the head elements in the center three rows up and down.
The distal end of the rear lever 63 is connected via a connecting rod 64 to a base 65 for a central head in which three rows of central head elements are arranged. The front lever 62 is a lever for moving up and down the head elements arranged on the left and right sides of the three rows of central heads. The front end of the front lever 62 has left and right head elements arranged via the connecting rod 66. The left and right head bases 67 are connected to each other. In the drawing, reference numerals 76 and 77 denote guide rods whose upper and lower ends are fixed to the machine frame.
The central head base 65 is guided above the base 67. Therefore, the electromagnetic clutch 26
Is turned off and only the center head base 65 moves up and down, the left and right head bases 67 do not interfere.

The movable head element 102 is slidable with respect to the fixed head element 101 in the product loading direction (depth direction), so that the distance between the movable head element 102 and the fixed head element 101 can be adjusted. It is configured to be able to. That is, FIG. 5 (in the case of the left and right heads) and FIG.
As shown in the figure (in the case of a central three-row head), the fixed head element 101 is mounted on upper portions of substantially L-shaped fixed mounting arms 68, 71 fixed to the bases 65, 67, The element 102 is disposed above the fixed mounting arms 68 and 71 so as to be slidable in the depth direction (substantially L-shaped).
Mounted on top of 72. In the drawing, reference numerals 70 and 73 denote rollers mounted below the movable mounting arms 69 and 72.
The rollers 70, 73 rotate on the upper end surfaces of the fixed mounting arms 68, 71 to facilitate the slide adjustment of the movable mounting arms 69, 72. The movable mounting arm 69 of the central three-row head is guided by the fixed mounting arm 68 by the guide mechanism 74 at the center, and the movable mounting arm 72 of the left and right heads is fixedly mounted by the guide mechanisms 75 on both the left and right sides. Is guided by Head size changing means G for slidingly moving the movable head element 102 includes a driving pulley 28 and a driven pulley 29 which are attached to a rotating frame of the head size changing motor 27 by attaching a head size changing motor 27 to the machine frame A. A guide frame 31 having a U-shaped cross section is fixed upright on the belt 30, and the guide frame 31 is a horizontal guide rod having two upper and lower portions fixed to the machine frame A in the height direction. 32 is slidably engaged. A movable mounting arm 69 in which the above-described three movable head elements 102 in the center are mounted on the guide frame 31 described above.
The roller 34 at the end of the arm 33 connected to the arm 33 and the roller 36 at the end of the arm 35 connected to the movable mounting arm 72 to which the left and right movable head elements 102 are attached are slidably fitted respectively. Have been. Thus, when the head size variable motor 27 is driven and the belt 30 rotates, the guide frame fixed to the belt 30
31 moves in the product loading direction (depth direction) along the horizontal guide rod 32, and accordingly, the arm rod 3 moves through rollers 34 and 36.
3 and 35 are also moved together, and the movable mounting arms 69 and 72 slide on the fixed mounting arms 68 and 71, so that the distance from the fixed head element 101 is changed. The adjustment for increasing or decreasing the interval is performed based on the forward rotation and the reverse rotation of the head size variable motor 27 described above. still,
A flag portion (not shown) is formed at a predetermined position of the belt 30, and an initial position (minimum head size position) is detected by detecting the flag portion with a sensor. Furthermore,
As described above, since the rollers 34 and 36 of the arm rods 33 and 35 are fitted to the guide frame 31 so as to be slidable up and down, the head elements can be moved up and down with the spacing between the head elements adjusted. is there. It is also possible to adjust the interval between the head elements while moving the head elements up and down.

The head size in the depth direction is changed by controlling the driving of the head size changing means G. The amount of change is determined by the depth dimension (length) of the goods to be carried in. The depth dimension of the product is measured during the loading of the product by a sensor S2 provided near the pusher conveyor B of the loading means, and is determined based on the measured value.

FIG. 8 shows the electrical configuration of the above-described apparatus, which includes a packaging mechanism control unit H and a weighing label printer control unit (not shown). The packaging mechanism control unit H is mainly composed of a mechanical unit of the packaging machine. Is controlled by the CPU 37, and the weighing label printer controller mainly controls the weighing label printer, but the description is omitted because it is not directly related to the present invention. CPU 37 has a bus 37a
Communication interface circuit (INF) 38, R
The OM 39, the RAM 40, the operation unit 41, the display unit 42, and the mechanism driving unit 43 are connected. The communication interface circuit (INF) 38 is a circuit for communicating various data and commands with the weighing label printer control unit. ROM39 is
A control program executed by the CPU 37 is stored.
The RAM 40 includes various registers and flags used when the CPU 37 executes the control program of the ROM 39, and various tables for determining control data based on product shape data (vertical width, width, height), and the like. Is stored. The operation unit 41 includes various switches for starting and stopping the apparatus and a keyboard for inputting data and the like. The display unit 42 is formed of a liquid crystal display of a dot type, and displays input data, displays preset data, and displays various messages such as a variable amount of a head size based on a command from the CPU 37. Also called console part.

The mechanism driving section 43 is a circuit for driving each mechanism section of the packaging machine when packaging is performed, and more specifically, a motor 44 for driving the elevator 1 and a driving motor for the conveyor B for loading goods. 45, Drive motor for film transfer means D
24, a drive motor 46 for operating left and right folding plates 4 and 4 'for folding the left and right ends of the film into the bottom of the product, a drive motor 47 for operating the folding plate 5 after folding the rear end of the film to the bottom of the product and discharging. A drive motor 48 for operating the pusher 6, a variable head size motor 27, a head size selection clutch (electromagnetic clutch) 26, and a film pre-stretch motor 49 for expanding the film transfer means D in the film width direction to pre-stretch the film width; Sensors S1, S2, S for detecting product size (width, height, height)
And a rotary encoder 51 for detecting a rotation angle of a cam 50 for driving the elevator 1. The rotary encoder 51 is attached to a shaft of a cam 50 for driving an elevator, counts output pulses from the rotary encoder 51, and detects the rotation angle of the cam based on the count value. Then, based on the rotation angle of the cam, the control of the [loading step], [thrusting step], [folding step], [unloading step] and [film transfer step] is performed.
When the cam 50 makes one rotation, the operation of one cycle of the packaging machine is completed. Then, a status signal (such as normal or error) of each control unit is exchanged between the above-described packaging mechanism control unit H and a weighing label printer control unit (not shown).

The head size variable motor 27 is a motor that slides the movable head element 102 in the depth direction. This motor is based on a value measured by a sensor S2 for measuring the vertical width of a product size detection sensor described later. Controlled. The head size selection clutch 26 is an electromagnetic clutch for selecting whether to make the head size "large" or "small" in the width direction of the product. As described above, the head elements in the center three rows of the elevator head and the left and right sides are used. The vertical movement of the head element is interrupted. The product size detection sensor comprises a sensor S1 for measuring the width (X) of the product, a sensor S2 for measuring the vertical width (Y) of the product, and a sensor S3 for measuring the height (Z) of the product. The measurement of the lateral width (X) is performed at the time of commencement of loading of the product by the sensor S1 installed on the front side of the product mounting table a. The vertical width (Y) and height (Z) of the product are detected during the loading of the product by sensors S2 and S3 provided near the pusher conveyor B. That is, the product moves by being pushed by the pusher attached to the pusher belt on the rear side. Since the pusher conveyor is driven by a pulse motor, the travel distance of the pusher can be detected by counting the drive pulses.

Now, a sensor S comprising a light emitting element and a light receiving element
Assuming that the front end of the product moved by the pusher is detected in Step 2, the vertical width (Y) of the product is calculated from the moving distance of the pusher at that time. That is, assuming that the moving distance of the pusher from the reference position is L1 and the distance from the reference position to the position where the sensor S2 is installed is L2, the vertical width of the product (Y) = L2−L1. Y) can be measured. The depth dimension in the head size of the elevator 1 is determined by the vertical width (Y) of this product (see FIG. 9). As shown in FIG. 10, the height (Z) of the product is such that a sensor S3 composed of a light-emitting element and a light-receiving element is placed at a predetermined interval in the height direction across a pusher conveyor B for carrying in the product. The three pairs are arranged, and each sensor is turned on when the light from the light emitting element is blocked by the product, whereby the height (Z) of the product is divided into three stages. That is, when only the lowermost sensor S3a is ON, "low", and the lowermost sensor S3a and the middle sensor S3b are ON.
Is detected as "medium", and when the three pairs of sensors S3a to S3c are ON, "high" is detected. The sensor S3a at the bottom also serves as the sensor S2 for measuring the vertical width (Y) of the above-mentioned product.

The cut length of the film used for packaging is determined based on the three levels of height (Z) detected by the sensor S3 and the detection data of the width (X) described above. Further, the pre-stretch amount of the film is determined by the vertical width (Y) and the height (Z) of the product. Basically, the width of the product (X) determines the film length, and the height of the product (Y) determines the head size and the amount of pre-stretching of the film. Since more is required, the length of the film is increased when the height (Z) of the product is high, and the amount of pre-stretching is increased for the amount of film pre-stretching. However, the head size of the elevator that supports and supports the product is determined only by the vertical width (Y) of the product. In the illustrated embodiment, the width of the head size is switched according to the width (X) of the product. That is, when the width (X) of the product is equal to or larger than a predetermined value, the “large head” (FIGS. 7A and 7C)
), And when the width (X) of the product is equal to or smaller than a predetermined value, a “small head” (see FIGS. 7B and 7D) is set.

Next, a mechanical time chart of the packaging machine will be described with reference to FIG. The packaging machine shown in the embodiment is a type that completes the packaging of one product in two cycles, and raises the elevator, folds the film left and right in the first half of one cycle, and wraps the product in the second half of one cycle. Carry out and pre-fold the film. Also,
In parallel with the above operations, the next product is carried into the elevator head, and the film for packaging the next product is pulled out and centered. Further, the drive / stop of the feeding roller 14 for feeding the film, the operation / stop of the cutter E, the vertical movement of the film holding means C, the film transfer means D
Each control of driving and stopping of the cam 50
Is performed based on the rotation angle, and when the cam makes one rotation, the operation of one cycle of packaging is performed. The rotation angle of the cam is detected by counting the output pulses from the rotary encoder 51 attached to the cam shaft as described above,
It is detected by the count value. Note that the scale displayed in FIG. 11 indicates the count value and the time together with the rotation angle of the cam 50 described above.

The measurement and detection of the product size have been completed at least by (a). (B) is a timing at which a product having the maximum vertical width (Y) is started to be carried into the elevator head. It is the gist of the present invention that the head size is adjusted (expanded) (h) between (a) and (b). The feature of the present embodiment is that the head size is returned to the initial position (minimum size) when the elevator head is lowered. (C) is the timing of film cutting, (C) the previous film feed is unreeled from a film roll of a predetermined length of film, and (C) the subsequent film feed is the centering of the film cut to a predetermined length. . After the film is cut, the film is pre-stretched (d). This is performed in parallel with the film feed during the beginning of the film pre-stretch. Then, the pre-stretching of the film is performed halfway up the elevator head. However, the pre-stretching of the film is completed at least before the product on the elevator head comes into contact with the film. The pre-stretch of the film is weakened when the upper surface of the product on the elevator comes into contact with the film and at an early stage of the folding back of the film. That is, it is moved in a direction to narrow (close) the interval between the film feed means. However, this narrowing position changes according to the elevator head size. That is, in (e), the film transport means D
Is not narrowed to the initial position (smallest interval = interval at the time of film feed). This is because the head size of the elevator head is variable. In the case where the head size is enlarged, if the interval of the film transport means is returned to the initial position in (e), the elevator head collides when the elevator descends. Therefore,
In (e), the head is narrowed to a position corresponding to the adjusted head size. In (f), the interval of the film transport means is returned to the initial position. At this time, the elevator head is also returning to the initial position (g). As described above, the return (g) of the elevator head to the initial position is performed in parallel with the lowering of the elevator head. This requires that the adjustment (h) of the elevator head be completed at least by (b), but this must be performed immediately after the detection of the size of the product (b). However, when the elevator head is returned to the initial position (g) after the elevator head is lowered, the adjustment (h) cannot be started, and the processing capacity is reduced accordingly. (This is because there is a condition that the size adjustment of the elevator head is always performed after it is once returned to the initial position. Otherwise, a reference position for adjustment cannot be obtained.)

FIG. 12 is a flow chart for explaining the "commodity carry-in process" and the "adjustment amount determination and elevator head size adjustment process", and do not accurately describe the control of the CPU. Actually, the CPU 37 controls the drive units such as the respective motors to execute the mechanical time chart shown in FIG. 11 based on the count value of the signal of the rotary encoder 51. (A) Commodity carry-in processing (SP1): It is checked whether or not the weighing of the commodities placed on the commodity placing section is stable. (If it is not a weighing and packaging machine, check whether the product is placed on the placing part.) (SP2) If the weighing is stable, start the carry-in conveyor and start carrying in the product. (SP3): Detecting the product size (vertical width and height) during loading. The width (X) of the product is detected after the start of the carry-in conveyor, but before the start of the carry-in of the product. (SP4): It is checked whether or not the product has been delivered to a predetermined position on the elevator head. Since the carry-in conveyor drive motor is a stepping motor, the carry-in distance is determined by counting the number of drive steps, and the check is performed based on the carry-in distance. (SP5) When the goods are carried into a predetermined position on the elevator head, the carry-in conveyor is stopped and the processing is terminated.

(B) Determination of Adjustment Amount and Elevator Head Size Adjustment Processing (Start) ... The processing of (A) is started after the execution of SP3. (SP10)... Based on the product size (width X, length Y, height Z) detected in SP3, the following adjustment amounts and various control data (opening timing of the film clamp, etc.) are determined. Here, the adjustment amount of the head size, the film pre-stretch amount, and the selection of the elevator head related to the present invention will be described. Determination of Head Size Adjustment (ΔH) This is determined using a conversion table stored in the ROM 39 in advance. For example, when the vertical width (Y) of the product is Y5 ≦ Y <Y4, the adjustment amount (ΔH) is set to 40 mm. (Continued on next page) (Continued on next page) Determination of film pre-stretch amount (ΔP) The film pre-stretch amount (ΔP) is determined based on the values of the vertical width Y and height Z of the product. As described above, since the height Z is of three types, “low”, “medium”, and “high”, a table of Y → ΔP is stored in the ROM 39 in advance for each type of height Z. The adjustment amount (mm) of ΔP is 10 steps of 50, 100, 150, 200, 250, 300, 350, 400, 450, and 500. Head selection (selection by electromagnetic clutch) Width X ≧ Xo → Large head (Electromagnetic clutch ON) Width X <Xo → Small head (Electromagnetic clutch OFF) (SP11) ... Performs elevator head size adjustment processing. This process is the process (h) of the mechanical time chart shown in FIG. (Note that the head is selected by turning on the electromagnetic clutch when the elevator head is raised. The film pre-stretch is performed in (d) of the mechanical time chart).

Specifically, the processing shown in FIG. 13 is performed. (SP20): The adjustment amount ΔH is set in the register.
(Step number of stepping motor) (SP21) ... The head size variable motor 27 (pulse motor = stepping motor) is started for one step. (SP22) Decrement the adjustment amount ΔH (subtract -1)
I do. (SP23) Check whether the adjustment amount ΔH is “0”. If (YES), the adjustment ends. This (YES) means that the stepping motor is driven by the number of steps set in SP20. The adjustment of the pre-stretch amount is performed by the same processing, but the description is omitted because it is not directly related to the gist of the present invention.

In the above-described embodiment, one type of narrow film is pre-stretched in the width direction according to the vertical width (Y) of the product in which the film is wrapped, so that the wrapping is performed without changing the film. Since it is a type of packaging machine, only the adjustment in the depth direction is performed by the slide method (the method of the present invention) in the adjustment of the head size, and the size adjustment in the width direction is performed by selecting the head to be used as in the conventional case.
However, the present invention is not limited to this configuration, and the size adjustment in the width direction may not be performed, and the slide method may be used similarly to the adjustment in the depth direction. Further, depending on the configuration of the packaging machine, a configuration in which a slide method is used for adjusting the head size in the width direction and the size is not adjusted in the depth direction, or a configuration in which the head is adjusted by selecting a head to be used is also conceivable. The point is that any device that changes at least one of the size in the depth direction and the width direction in a sliding manner during the transportation of a product is included in the scope of the present invention.

The structure of the head size changing means is not limited to the illustrated embodiment. For example, a structure using a wire and a spring as disclosed in Japanese Patent Application Laid-Open No. 7-232706 as a prior art may be used. However, in the case of the wire and the spring, the motor for winding the wire must be arranged on the elevator, so that the elevator structure is restricted. However, the embodiment of the present invention does not have such a disadvantage.

[0033]

According to the present invention, according to the first aspect,
Since the head size of the elevator is adjusted in parallel with the loading of the goods by the loading means, the head size adjustment time is not wasted. In addition, the size of the commodity (vertical width)
Is detected during the loading process, the variable amount of the head size is determined based on the detection result, and the head size is adjusted before the product is loaded onto the elevator head.
The head size adjustment time is not a waste time. The head size is adjusted for each product without depending on the size of the product without wasting time. Therefore, even when a large number of products of different sizes are processed, the processing capacity does not decrease. Furthermore, by pre-stretching in the width direction according to full Irumu goods size, it is of a type packaging machine that performs without packaging exchanging film with one type of film narrow, always without dead time product Since the elevator head can have a size corresponding to the size, beautiful packaging can be performed regardless of the product size. or,
According to the configuration of the second aspect , since the return from the adjusted head size to the initial size is performed in parallel with the lowering of the elevator, the time required to return to the initial size does not become a waste time.

[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 an enlarged plan view showing a portion of a loading means and an elevator.

FIG. 4 is an enlarged rear view of the same part.

FIG. 5 is a longitudinal sectional view taken along line (X)-(X) in FIG. 4;

FIG. 6 is a longitudinal sectional view taken along the line (Y)-(Y) of FIG.

FIG. 7 is an explanatory diagram showing the size adjustment of the elevator head.

FIG. 8 is an explanatory diagram showing an electrical configuration of a control unit of the packaging machine shown in FIG.

FIG. 9 is an explanatory diagram showing the principle of detecting the vertical width (Y) of a product.

FIG. 10 is an explanatory diagram showing a structure for detecting the height (Z) of a product.

FIG. 11 is a mechanical time chart of the same device.

FIG. 12 is a flowchart illustrating control of a product carrying-in process and control of a process of determining an adjustment amount.

FIG. 13 is a flowchart illustrating head size adjustment control.

[Explanation of symbols]

B: Loading means (pusher conveyor) D: Film transfer means F: Elevator head G (26): Head size variable means H: Packaging mechanism control unit S2: Vertical width detection means (sensor) a: Product placement part b: Packaging Part 1: Elevator

Claims (2)

(57) [Claims] 1. A film cut to a predetermined length while sandwiching both side edges in the width direction of the film is conveyed to a packaging position, and the film is pre-stretched in the width direction and stretched to a packaging position. In a stretch film wrapping machine that covers the upper surface of the product by pushing up the product from the lower side by raising the elevator with the product carried on the elevator head, (a) carrying-in means for carrying the product onto the elevator head (B) sandwiching both side edges in the width direction of the film, and
A pair of Fi Lum transport means for transporting the location, to extend the distance (c) the pair of film transport means
In the film width extension means extend the film in the width direction, (d) and head size varying means for an elevator head widening or narrowing adjust the spacing of a plurality of head elements constituting the elevator head, (e) said carrying means And (f) determining the amount of expansion of the film width and the variable amount of the head size variable means based on the detection result of the vertical width detection means. Determining means, (g) performing drive control of the head size variable means before the product is carried into the head based on the determination result of the determining means, and terminating the adjustment of the head size,
A stretch film packaging machine comprising: a control means for controlling the drive of the film width expanding means to terminate the expansion of the film width at least before the upper surface of the product comes into contact with the film by raising the elevator head. 2. The stretch according to claim 1, wherein said control means drives and controls said head size changing means when the elevator is lowered to adjust the head size of the elevator head to a predetermined initial size. Film wrapping machine.