Stretch packaging device

Abstract

To provide a stretch packaging device capable of performing packaging with less wrinkles, while shortening use length of a film.SOLUTION: A stretch packaging device 1 comprises: a film-conveying part 6 for conveying a film F to a packaging area A by holding both sides therebetween in a width direction; a lift part 20 for pushing up the film in a state where a commodity product is pressed onto the film from below; a pair of folding plates 26, 27 each for folding a peripheral edge part of the pushed-up film onto a bottom face side of the commodity product; a presser plates 38, 39 for pressing both ends in a conveyance direction of the film located below each of the folding plates, respectively; a movement mechanism 36 for moving a pair of clamps; and a control part 9 for controlling movement of the pair of folding plates. The control part pre-stretches the film by moving at least one of the pair of the folding plates in a state where the film is pressed by the pair of clamps, in a direction where a relative distance is separated from each other.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] One aspect of the present invention relates to a stretch wrapping apparatus. [Background technology]

[0002] A stretch wrapping device (for example, Patent Document 1 shown below) is known in which weighed products are brought in by a conveyor, the products are raised by a lift unit provided inside, the products are pushed up against a film stretched above the lift unit, and the end of the film is folded over the bottom of the product to wrap it (wrap it). Such a stretch wrapping device includes a film transport unit that clamps both sides in the width direction perpendicular to the transport direction of the film fed from the film roll and transports the film to the wrapping area. The film transport unit stretches the film in the width direction by moving the film so that the relative distance between the clamped parts on both sides is larger than the width size of the film. The stretch wrapping device makes it possible to wrap the products with fewer wrinkles by pushing up the products against the film that has been stretched in the width direction in advance (pre-stretched) in this way. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-57004 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional stretch wrapping device, although the film is pre-stretched in the width direction, the film is not pre-stretched in the conveying direction, which means that in order to wrap the product with fewer wrinkles, it is necessary to use a film that is much longer than the length of the film that covers the product.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of one aspect of the present invention is to provide a stretch wrapping device that can perform wrapping with fewer wrinkles while shortening the length of film used. [Means for solving the problem]

[0006] (1) A stretch wrapping device according to one aspect of the present invention includes a film conveying unit that clamps both sides of the film in a width direction perpendicular to the conveying direction and conveys the film to a packaging area, a lifting unit that pushes up the film conveyed to the packaging area by moving the film upward while pressing a product against the film from below, a pair of folding plates that fold the peripheral portion of the film pushed up by the lifting unit toward the bottom of the product, a pair of clamps that grip both ends of the film in the conveying direction located below the pair of folding plates, a moving mechanism that moves the pair of clamps, and a control unit that controls the movement of the moving mechanism, and the control unit controls the moving mechanism to move at least one of the pair of clamps in a direction that increases the relative distance between the pair of clamps to pre-stretch the film in the film conveying direction.

[0007] In a stretch wrapping device with this configuration, the film stretched along the conveying direction (pre-stretched state) is pushed up by the product. As a result, the film is wrapped in a state where it is stretched along the conveying direction, so the length of the film used can be shorter than when wrapping is performed without stretching the film along the conveying direction. In other words, with this configuration, it is possible to perform wrapping with fewer wrinkles while shortening the length of the film used.

[0008] (2) In the stretch wrapping device described in (1) above, the pair of clamps is composed of a pair of folding plates and a pair of pressing plates that press the film against each of the pair of folding plates from below, the moving mechanism is configured to move the pressing plates in accordance with the movement of the folding plates, and the control unit may move at least one of the folding plates in a state in which both ends of the film in the conveying direction are pressed against each folding plate by the pair of pressing plates in a direction in which the relative distance between them increases. In this configuration, the existing folding plates and folding plate moving configuration that fold both ends of the film in the conveying direction toward the bottom side of the product by moving toward and away from each other in the film conveying direction can be utilized, so there is no need to incorporate a separate moving mechanism that moves the pair of clamps toward and away from each other in the film conveying direction, and therefore the clamps that hold the film can be constructed at low cost. In addition, by simply pressing both ends of the film in the transport direction against the left and right folding plates with the left and right pressure plates, respectively, the pair of pressure plates can be moved in conjunction with the movement of the pair of folding plates, eliminating the need for control to synchronize their movements, allowing for a simple configuration and control.

[0009] (3) In the stretch wrapping device described in (1) or (2) above, the film conveying section may include a pair of clamping units arranged opposite each other in the width direction of the film, and the control section may move at least one of the pair of clamping units in a direction increasing the relative distance between them before the film is pushed up by the product. In this configuration, the film can be pre-stretched in both the conveying direction and the width direction of the film, and as a result, the product is pushed up against the film that has been pre-stretched lengthwise and widthwise, enabling packaging with even fewer wrinkles. Effect of the Invention

[0010] According to one aspect of the present invention, packaging with fewer wrinkles can be achieved while shortening the length of film used. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1 is an external perspective view showing a packaging device according to an embodiment. [Diagram 2] FIG. 2 is a schematic front view showing the inside of the stretch wrapping device of FIG. [Diagram 3] FIG. 3 is a schematic view taken along line III-III in FIG. [Figure 4] FIG. 4 is a schematic plan view of a stretch wrapping apparatus. [Diagram 5] FIG. 5 is a block diagram showing the configuration of the stretch wrapping device of FIG. [Figure 6] FIG. 6 is a perspective view of the stretching mechanism as seen diagonally from the front right. [Figure 7] FIG. 7 is a perspective view of the stretching mechanism as seen obliquely from the rear left. [Figure 8] FIG. 8 is a perspective view of the stretching mechanism as seen obliquely from the rear left. [Figure 9] Fig. 9(A) is an enlarged perspective view of the first clamp in the outer position and the original position, Fig. 9(B) is an enlarged perspective view of the first clamp in the outer position and the stretch position, and Fig. 9(C) is an enlarged perspective view of the first clamp in the inner position and the original position. [Figure 10] FIG. 10 is a diagram showing the operation when wrapping an object. [Figure 11] FIG. 11 is a diagram showing the operation when wrapping an object. [Figure 12] FIG. 12 is a diagram showing the operation when wrapping an object. [Figure 13] 13(A) to 13(F) are diagrams showing the operation of the first clamp when pre-stretching the film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a stretch wrapping device 1 according to one embodiment will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted.

[0013] 1 to 4, the stretch wrapping device 1 is a device that wraps, in film, an object (item) W, which includes a product G such as food or the like, and a tray T on which the product G is placed. The stretch wrapping device 1 pushes the object W from below against a film F that holds the peripheral portion taut, and wraps the object W in the film F by folding the peripheral portion of the film F toward the bottom side of the tray T.

[0014] The stretch wrapping device 1 includes a weighing and carrying-in mechanism 2, a roll holding mechanism 4, a film sending mechanism 5, a film transport mechanism (film transport section) 6, a cutter mechanism 7, a lift mechanism (lift section) 20, a folding mechanism 25, a sealing mechanism 8, a label issuing machine LI, and a control device (control section) 9. Each mechanism included in the stretch wrapping device 1 is housed in a main body 1A and a casing 1B of the stretch wrapping device 1. The casing 1B is attached to the side of the main body 1A.

[0015] In the description of this embodiment, "left and right" refer to left and right when the main body 1A of the stretch wrapping device 1 is viewed from the front. The front side in the front-to-rear direction of the stretch wrapping device 1 is referred to as the "front side," and the opposite side is also referred to as the "rear side." Films F1, F2 refer to any one of films F1 and F2, and are also simply referred to as film F. Film rolls R1, R2 refer to any one of film roll R1 and film roll R2. "Upstream" and "downstream" refer to the upstream and downstream sides of the transport direction of film F, respectively.

[0016] As shown in Fig. 3, the weighing carry-in mechanism 2 has a weighing device 2A, a carry-in belt 2B, and a weighing dish 12. The weighing device 2A weighs the object W placed on the weighing dish 12, and outputs information indicating the weight of the object W to the control device 9. The carry-in belt 2B is stretched between a pair of rollers. The carry-in belt 2B is provided with a conveyor bar 13 that pushes the object W. The conveyor bar 13 moves to the rear side as the carry-in belt 2B travels, and pushes the object W to the lift mechanism 20 at the rear side. The weighing dish 12 is a rectangular shallow tray on which the object W is placed.

[0017] As shown in Fig. 2, the roll holding mechanism 4 is installed in the casing 1B. The roll holding mechanism 4 has a configuration for holding two film rolls R1, R2 of the same or different types. Each of the film rolls R1, R2 is formed by multiple windings of films F1, F2 of a predetermined width. The roll holding mechanism 4 includes an upper roll holding section 41 that holds the film roll R1, a lower roll holding section 42 that holds the film roll R2, and a roll drive section 43 that selectively rotates either the upper roll holding section 41 or the lower roll holding section 42 to unwind the film F1 or the film F2 from either the film rolls R1, R2.

[0018] The film feeding mechanism 5 is a mechanism that delivers the film F1 pulled out from the film roll R1 or the film F2 pulled out from the film roll R2 to a pair of first feeder unit 61 and second feeder unit 62 of the film transport mechanism 6. The film feeding mechanism 5 is installed in the casing 1B. The film feeding mechanism 5 includes a loading unit 70 and a drive unit 74. The loading unit 70 has a first gripping unit 71, a second gripping unit 72, a rotating shaft 73, and the drive unit 74. The first gripping unit 71 and the second gripping unit 72 are attached to the rotating shaft 73. The first gripping unit 71 and the second gripping unit 72 extend in a V shape from the rotating shaft 73 when viewed from the front-rear direction.

[0019] 4, first gripping unit 71 grips film F1 with two plate members 71A, 71B. Second gripping unit 72 grips film F2 with two plate members 72A, 72B. First gripping unit 71 and second gripping unit 72 have a predetermined length in the depth direction of casing 1B so that films F1, F2 can be sent out to film transport mechanism 6. Drive unit 74 rotates rotation shaft 73 to rotate first gripping unit 71 and second gripping unit 72.

[0020] 2, when the first gripping unit 71 delivers (sends) the film F1 to the film transport mechanism 6, the rotation shaft 73 is rotated until the first gripping unit 71 becomes parallel to the horizontal plane. As a result, the film F1 is sent out horizontally from the tip of the first gripping unit 71 to the film transport mechanism 6. When the second gripping unit 72 delivers the film F2 to the film transport mechanism 6, the rotation shaft 73 is rotated until the second gripping unit 72 becomes parallel to the horizontal plane. As a result, the film F2 is sent out horizontally from the tip of the second gripping unit 72 to the film transport mechanism 6.

[0021] The film transport mechanism 6 receives the film F from the film delivery mechanism 5, vertically clamps both sides in the width direction (front-rear direction) of the film F, and transports the film F to the packaging area A above the lift mechanism 20. The film transport mechanism 6 also holds the film F received from the film delivery mechanism 5 under tension in the center of the packaging area A. The film transport mechanism 6 includes a first feeder unit 61 (clamping unit), a second feeder unit (clamping unit) 62, a first transport drive unit 63 shown in FIG. 4, a first slide mechanism 64, a second slide mechanism 65, a second drive unit 66, and a third drive unit 67.

[0022] As shown in FIG. 2 and FIG. 3, the first feeder unit 61 includes a first feeder section 61A and a pair of clamping sections 61B, 61C. The first feeder section 61A transports the film F sent out from the film delivery mechanism 5. The pair of clamping sections 61B, 61C clamp the film F transported by the first feeder section 61A in the vertical direction. The pair of clamping sections 61B, 61C are actuated by the on / off switching of a solenoid (not shown). Specifically, the pair of clamping sections 61B, 61C clamp or release the film F by the on / off switching of the solenoid. The clamping section 61B may be formed of multiple members (three members in FIG. 10 to FIG. 13) in the transport direction.

[0023] The second feeder unit 62 includes a second feeder section 62A and a pair of clamping sections 62B, 62C. The second feeder section 62A transports the film F sent out from the film delivery mechanism 5. The pair of clamping sections 62B, 62C clamp the film F transported by the second feeder section 62A in the vertical direction. The pair of clamping sections 62B, 62C clamp or release the film F by switching on / off a solenoid (not shown). The clamping section 62B may be formed of multiple members (three members in FIGS. 10 to 13) in the transport direction.

[0024] The first feeder unit 61 shown in Fig. 2 is disposed on the front side in the front-rear direction. The second feeder unit 62 is disposed on the rear side in the front-rear direction relative to the first feeder unit 61. The first feeder unit 61 and the second feeder unit 62 are disposed along the conveying direction (longitudinal direction) of the film F. The first feeder unit 61 and the second feeder unit 62 are driven by a first conveying drive section 63 shown in Fig. 4, and convey the film F from the left side to the right side.

[0025] A first slide mechanism 64 and a second slide mechanism 65 are provided at both longitudinal ends of the first feeder unit 61 and the second feeder unit 62 shown in Fig. 2, for moving the first feeder unit 61 and the second feeder unit 62 in the width direction of the film F. The first slide mechanism 64 is driven by a second drive unit 66 shown in Fig. 3, and moves the first feeder unit 61 in the width direction of the film F. The second slide mechanism 65 is driven by a third drive unit 67, and moves the second feeder unit 62 in the width direction of the film F.

[0026] 2 cuts the film F stretched between the film feed-out mechanism 5 and the film transport mechanism 6 after the film feed-out mechanism 5 delivers the film F to the film transport mechanism 6. The cutter mechanism 7 cuts the film F stretched between the film feed-out mechanism 5 and the film transport mechanism 6 after the film transport mechanism 6 transports a predetermined amount of film F.

[0027] In this embodiment, the film F cut by the cutter mechanism 7 is pre-stretched in the transport direction and width direction of the film F. The pre-stretching of the film F in the width direction is performed by driving the third drive section 67 to move the second feeder unit 62 backward while the film F is sandwiched between the first feeder unit 61 and the second feeder unit 62. The pre-stretching of the film F in the transport direction will be described in detail later.

[0028] The lift mechanism 20 is provided at the bottom of the main body 1A. The lift mechanism 20 supports the bottom surface of the tray T with a plurality of support members 23, and moves a support base 21 fixed to the support members 23 upward by an electric ball screw mechanism 24. In this way, the lift mechanism 20 holds the bottom surface of the tray T and moves the object W upward. The lift mechanism 20 pushes up the film F by moving the object W vertically while pressing it against the film F, which is held taut by the film transport mechanism 6.

[0029] As shown in FIG. 2 and FIG. 3, the folding mechanism 25 is provided in the upper part of the main body 1A. The folding mechanism 25 folds the peripheral part of the film F onto the bottom side of the object W pushed up by the lift mechanism 20 (i.e., the bottom side of the tray T), and covers the object W with the film F. The folding mechanism 25 has a first folding plate 26 and a second folding plate 27 that are provided so as to be movable horizontally along the conveying direction of the film F. The first folding plate 26 and the second folding plate 27 fold the film F from both ends in the conveying direction of the object W to the bottom side of the tray T. The folding mechanism 25 has a third folding plate 28 that folds the side part on the rear side in the width direction of the film F into the bottom side of the tray T. The folding mechanism 25 has a front folding rod 29 that folds the side part on the front side in the width direction of the film F into the bottom side of the tray T when the tray T is discharged to the sealing mechanism 8 side by the discharge pusher 29A. The first folding plate 26, the second folding plate 27, and the third folding plate 28 have one drive unit (not shown) and are configured to be driven in conjunction with one another by a plurality of pulleys and a timing belt, etc. Note that the first folding plate 26, the second folding plate 27, and the third folding plate 28 may be provided with an independent drive unit for moving to a start position according to the size of the target object W.

[0030] The stretching mechanism 3 shown in Fig. 6 is a mechanism that holds the film F in a state in which it is pulled (pre-stretched) in the transport direction (left-right direction) before the object W pushes up the film F by the lift mechanism 20. The stretching mechanism 3 is disposed at the rear of the main body 1A. As shown in Figs. 6 to 8, the stretching mechanism 3 includes a support portion 31, a vertical movement mechanism 32, a first arm 34, a second arm 35, a movement mechanism 36, and a first clamp 40A and a second clamp 40B (a pair of clamps).

[0031] First clamp 40A and second clamp 40B respectively grip both ends in the conveying direction of film F that are located below first folding plate 26 and second folding plate 27 (a pair of folding plates). First clamp 40A is composed of first pressing plate 38 and first folding plate 26, and clamps one end of film F in the conveying direction. Second clamp 40B is composed of second pressing plate 39 and second folding plate 27, and clamps the other end of film F in the conveying direction.

[0032] The support part 31 is a member that supports the first arm 34 and the second arm 35. The support part 31 has a main surface part 31A and a pair of side parts 31B, 31B, and is formed in a U-shape in a plan view. A slide mechanism 31D such as a linear guide or a cylinder is provided on the pair of side parts 31B, 31B of the support part 31, and the support part 31 is fixed to the main body 1A by this slide mechanism 31D so as to be movable in the vertical direction. The vertical movement mechanism 32 is a mechanism that moves the support part 31 in the vertical direction relative to the main body 1A.

[0033] The vertical movement mechanism 32 has a link mechanism 32A and a main body drive unit 32B. The link mechanism 32A is composed of a support shaft 32As supported by the main body 1A, a swing arm 32Ad that moves up and down around the support shaft 32As, a crank mechanism 32Ae connected to the rotating shaft of the swing arm 32Ad and the main body drive unit 32B, and a connecting rod 32Af that connects one end of the swing arm 32Ad to the support unit 31. The support unit 31 is moved in the vertical direction by rotating the rotating shaft of the main body drive unit 32B and operating the crank mechanism 32Ae. The main body drive unit 32B is attached to the main body 1A via a bracket 3A or the like. The main body drive unit 32B is controlled by the control device 9.

[0034] The first arm 34 is formed of a parallel link and is supported on the right end of the support portion 31. A base end 34A of the first arm 34 on the support portion 31 side is rotatably connected to the support portion 31. A first pressing plate 38 is provided on a tip end 34B of the first arm 34 opposite to the base end 34A via a mounting member 34C. As shown in FIG. 9(A), a guide member 34D that slidably moves the first pressing plate 38 is provided on the upper part of the mounting member 34C. The guide member 34D is a member that extends in one direction. As shown in FIG. 9(A) and FIG. 9(C), even when the first arm 34 rotates in the horizontal direction, the mounting member 34C connected to the tip end 34B of the first arm 34 is rotatably provided so that the guide member 34D maintains a state in which it extends in the left-right direction by the parallel link of the first arm 34.

[0035] Returning to Figs. 6 to 8, the second arm 35 is also formed of a parallel link like the first arm 34, and is supported on the left end of the support 31. A base end 35A of the second arm 35 on the support 31 side is rotatably connected to the support 31. A second pressing plate 39 is provided on a tip end 35B of the second arm 35 opposite to the base end 35A via a mounting member 35C. Like the first arm 34, a guide member 35D that slidably moves the second pressing plate 39 is provided on the upper part of the mounting member 35C. The guide member 35D is a member that extends in one direction. Even when the second arm 35 rotates in the horizontal direction, the mounting member 35C connected to the tip end 35B of the second arm 35 is rotatably provided so that the guide member 35D maintains a state in which it extends in the left-right direction by the parallel link of the second arm 35.

[0036] The first arm 34 and the second arm 35 are provided with a moving mechanism 36 described later for moving the first pressing plate 38 and the second pressing plate 39 following the first folding plate 26 and the second folding plate 27 that move to a start position according to the size of the target object W. The second pressing plate 39 provided on the second arm 35 via the attachment member 35C is in a state in which the first pressing plate 38 provided on the first arm 34 via the attachment member 34C as shown in Fig. 9(A) is inverted from left to right. For this reason, the second pressing plate 39 provided on the second arm 35 via the attachment member 35C corresponding to Figs. 9(A) to 9(C) is omitted from illustration.

[0037] 7 and 8 rotates the base ends 34A, 35A of the first arm 34 and the second arm 35 as base axes, thereby moving a first pressing plate 38 attached to the tip end 34B of the first arm 34 via a mounting member 34C and a second pressing plate 39 attached to the tip end 35B of the second arm 35 via a mounting member 35C toward or away from each other in the left-right direction. The moving mechanism 36 includes a rotation drive unit 36A, a plurality of pulleys 36B, and a timing belt 36C, as shown in FIG.

[0038] In the moving mechanism 36, the rotation drive unit 36A is driven, and a timing belt 36C wound around a plurality of pulleys 36B runs to rotate the pulleys 36B, so that the first arm 34 and the second arm 35 move toward and away from each other in the horizontal direction in a synchronized state. Specifically, the moving mechanism 36 rotates the first arm 34 and the second arm 35, thereby moving the first pressing plate 38 of the tip portion 34B of the first arm 34 to a position below the first folding plate 26 that has moved to the start position, and moving the second pressing plate 39 of the tip portion 35B of the second arm 35 to a position below the second folding plate 27 that has moved to the start position.

[0039] The first pressing plate 38, which has moved below the first folding plate 26, is provided so as to be movable in the same direction as the movement direction (left-right direction) of the first folding plate 26, with the film F sandwiched between it and the first folding plate 26. Specifically, the first pressing plate 38 moves to the right with the film F sandwiched (held) between it and the first folding plate 26, thereby pulling the film F to the right and tensioning (pre-stretching) the film F to the right. In addition, the second pressing plate 39, which has moved below the second folding plate 27, moves to the left with the film F sandwiched (held) between it and the second folding plate 27, thereby pre-stretching the film F to the left.

[0040] 9(A) and 9(B), the first pressing plate 38 is provided movably along the guide member 34D. The first pressing plate 38 has an elastic member 38A shown in FIG. 13(A) that biases the first pressing plate 38 in a direction returning to its original position (leftward) when the first pressing plate 38 moves in a direction away from the second pressing plate 39 (rightward).

[0041] The first pressing plate 38 is provided with a latched portion 38B that is hooked to the latch portion 26A (see FIG. 13A) of the first folding plate 26. The latched portion 38B of the first pressing plate 38, which has risen by the operation of the vertical movement mechanism 32, is located to the right of the latch portion 26A of the first folding plate 26 with the film F sandwiched between the first folding plate 26 and the latched portion 38B of the first pressing plate 38. When the first folding plate 26 moves to the right in this state, the latched portion 38B of the first pressing plate 38 is hooked to the latch portion 26A, and the first pressing plate 38 moves to the right. When the first pressing plate 38 moves downward by the operation of the vertical movement mechanism 32, the latched portion 38B of the first folding plate 26 is separated from the latch portion 26A of the first folding plate 26, and the first pressing plate 38 is returned to the left end of the guide member 34D by the biasing force of the elastic member 38A.

[0042] The second presser plate 39 rises together with the first presser plate 38 due to the operation of the vertical movement mechanism 32. Since the second presser plate 39 has a configuration symmetrical to the first presser plate 38, when the second folding plate 27 moves to the left with the film sandwiched between the second presser plate 39 and the second folding plate 27, the second presser plate 39 moves to the left in conjunction with the movement of the second folding plate 27 to the left. When the second presser plate 39 descends together with the first presser plate 38, the engaging portion of the second presser plate 39 separates from the second folding plate 27 and returns to the left end of the guide member 34D due to the biasing force of an elastic member (not shown).

[0043] The sealing mechanism 8 heat-seals the film F folded onto the bottom surface of the object W by the folding mechanism 25. The sealing mechanism 8 has a conveying roller and a heating roller, and heat-seals the object W pushed out by the discharge pusher 29A while conveying it with the conveying roller and the heating roller. The sealing mechanism 8 discharges the packaged object W toward the discharge table 82.

[0044] The label issuing machine LI includes an application machine that applies labels printed by a label printer LP to the discharged packaged products. The label printer LP prints information about the product on the labels. The information about the product is, for example, the product name and price.

[0045] The control device 9 is a computer disposed on the upper part of the main body 1A. The control device 9 controls the operation of each of the above-mentioned mechanisms. The control device 9 has an input / output interface I / O for inputting and outputting signals from and to the outside, a ROM (Read Only Memory) in which programs and information for performing processing are stored, a RAM (Random Access Memory) for temporarily storing data, a storage medium such as a HDD (Hard Disk Drive), a CPU (Central Processing Unit), and a communication circuit. The control device 9 realizes each function by storing input data in the RAM, loading the program stored in the ROM into the RAM, and executing the program loaded into the RAM based on a signal output by the CPU.

[0046] A display panel 16 and an operation unit 17 are connected to the control device 9. The display panel 16 is, for example, a touch panel display, and operation buttons are also displayed on the display. The operation unit 17 allows the user to perform various operations and inputs. The control device 9 refers to various data in the memory unit 9A, and calculates the price of the object W based on the weight and / or tray size of the object W weighed by the weighing and carrying-in mechanism 2. The control device 9 controls the operation of the label printer LP and label issuing machine LI, and prints the weight or price, etc. of the object W on a label.

[0047] The control device 9 of this embodiment moves the second feeder unit 62 of the pair of feeder units (first feeder unit 61 and second feeder unit 62) in a direction away from the first feeder unit 61 (in the depth direction) before the film F is pushed up by the object W. This pre-stretches the film F arranged above the packaging area A in the width direction. In addition, the control device 9 of this embodiment moves the first folding plate 26 and the second folding plate 27, and the first pressing plate 38 and the second pressing plate 39 to a position (start position) according to the size of the object W before the film F is pushed up by the object W. Next, the first pressing plate 38 and the second pressing plate 39 are raised to move both the first folding plate 26 and the second folding plate 27 in a direction in which the relative distance between them increases while the film F is pressed down by the first pressing plate 38 and the second pressing plate 39. This pre-stretches the film F arranged above the packaging area A in the conveying direction. The control device 9 pushes up the object W against the film F that has been pre-stretched in both the width direction and the conveying direction in this manner. That is, the control device 9 controls the lift mechanism 20 to move the object W upward.

[0048] In this embodiment, the left and right first folding plates 26 and second folding plates 27 are moved away from each other in the transport direction of the film F while the end of the film F is sandwiched between the first folding plate 26 and the first pressure plate 38, and between the second folding plate 27 and the second pressure plate 39, respectively, to pre-stretch the film F in the transport direction. However, instead of this configuration, a first clamp 40A and a second clamp 40B are provided to hold the end of the film F from above and below, and these first clamp 40A and second clamp 40B are moved away from each other in the left-right direction by the aforementioned moving mechanism 36, thereby pre-stretching the film F in the transport direction.

[0049] Next, the operation of the stretch packaging device 1 configured as above when the film F is pre-stretched in both the width direction and the conveying direction to package the object W will be described mainly with reference to Figs. 10 to 12.

[0050] When the film F is wrapped around the object W, the film F is transported by the film transport mechanism 6 to above the packaging area A, and the upstream side of the film F in the transport direction is cut by the cutter mechanism 7, so that the film F covers the object W above, as shown in Fig. 10 (1). In this state, the second feeder unit 62, which holds the film F on one side in the width direction of the film F, moves backward. This completes the pre-stretching of the film F in the width direction.

[0051] 13(A), first pressure plate 38 and second pressure plate 39 rise, and as shown in FIG. 10(2) and FIG. 13(B), film F is pressed against the lower surfaces of first folding plate 26 and second folding plate 27. As a result, the right end of film F in the conveying direction is clamped between first folding plate 26 and first pressure plate 38, and the left end of film F in the conveying direction is clamped between second folding plate 27 and second pressure plate 39.

[0052] In the state shown in FIG. 10(2), the first folding plate 26 is moved to the right, and the second folding plate 27 is moved to the left. As a result, the first pressing plate 38 having the locked portion 38B hooked on the locking portion 26A of the first folding plate 26 moves to the right with the movement of the first folding plate 26, as shown in FIG. 13(C). In addition, the second pressing plate 39 having the locked portion 39B hooked on the locking portion 27A of the second folding plate 27 also moves to the left with the movement of the second folding plate 27. As a result, as shown in FIG. 11(3), both ends of the film F in the conveying direction are pulled toward each other, completing the pre-stretching of the film F in the conveying direction.

[0053] Next, the object W is pressed against the film F, which has completed pre-stretching in the width direction and conveyance direction, to push the film F upward. For a while after the object W starts to push the film F upward, as shown in Fig. 11(4), Fig. 13(D) and Fig. 13(E), the first pressing plate 38 and the second pressing plate 39 keep the film F pressed against the lower surfaces of the first folding plate 26 and the second folding plate 27. In other words, the position of the peripheral edge of the film F remains fixed.

[0054] Next, at an appropriate timing after the target object W reaches the uppermost position, the first feeder unit 61, the first pressing plate 38, and the second pressing plate 39 release the clamping of the peripheral portion of the film F. Specifically, the first feeder unit 61 releases the clamping of the film F by increasing the distance between the pair of clamping portions 61B, 61C. Also, as shown in FIG. 13(F), the support portion 31 moves downward, increasing the distance between the first pressing plate 38 and the first folding plate 26 and the distance between the second pressing plate 39 and the second folding plate 27, thereby releasing the clamping of the film F. At this time, the first pressing plate 38 and the second pressing plate 39 return to the start position shown in FIG. 10(1) by the action of the respective elastic members 38A.

[0055] Next, as shown in FIG. 12 (5), the first folding plate 26 moves to the left, and the second folding plate 27 moves to the right, folding the peripheral portion of the film F in the conveyance direction toward the bottom side of the object W. Next, as shown in FIG. 12 (6), the third folding plate 28 moves forward, folding the peripheral portion of the film F in the width direction toward the bottom side of the object W. Finally, the discharge pusher 29A moves forward to push the object W toward the sealing mechanism 8. At this time, the film F on the front side of the object W is folded toward the bottom side of the object W. This completes the packaging of the object W with the film F.

[0056] The effect of the stretch wrapping device 1 of the above embodiment will be described. In the stretch wrapping device 1 of the above embodiment, the film F stretched along the conveying direction of the film F (pre-stretched state) is pushed up by the object W. As a result, the film F is wrapped in a state in which it is stretched along the conveying direction, so the length of the film F used can be shorter than when the film F is wrapped in a state in which it is not stretched along the conveying direction. In other words, with this configuration, it is possible to perform wrapping with fewer wrinkles while shortening the length of the film F used.

[0057] In the stretch wrapping device 1 of the above embodiment, the movement mechanism for moving the first pressure plate 38 and the second pressure plate 39 is configured so that the first pressure plate 38 and the second pressure plate 39 move in conjunction with the movement of the first folding plate 26 and the second folding plate 27. This makes it possible to pull both ends of the film F in the conveying direction, and the film F can be easily stretched in the conveying direction.

[0058] In the stretch wrapping device 1 of the above embodiment, the first pressure plate 38 and the second pressure plate 39 are configured to move in response to the movement of the first folding plate 26 and the second folding plate 27 when one end of the film F is pressed against the first folding plate 26 and the other end of the film F is pressed against the second folding plate 27. Therefore, in this embodiment, the first pressure plate 38 and the second pressure plate 39 are configured to be moved up and down by the vertical movement mechanism 32, but a first plate and a second plate that move up and down by a solenoid may be disposed above the first pressure plate 38 and the second pressure plate 39, respectively, and the end of the film F may be gripped between the first plate and the first pressure plate 38 and between the second plate and the second pressure plate 39, respectively.

[0059] In the stretch wrapping device 1 of the above embodiment, the control device 9 moves the second feeder unit 62 in a direction increasing the relative distance from the first feeder unit 61 before the film F is pushed up by the object W. This allows the film F, which has been pre-stretched in both the conveyance direction and the width direction of the film F, to be pushed up by the object W, making it possible to perform wrapping with even fewer wrinkles.

[0060] Although one embodiment has been described above, one aspect of the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit and scope of the invention.

[0061] In the above embodiment, an example of a stretch wrapping device 1 that has a film wrapping function as well as a weighing function and a pricing function by label attachment was described, but the stretch wrapping device 1 may be configured to not have at least one of the weighing function and the pricing function.

[0062] In the above embodiment and modified examples, examples have been given in which both the first pressure plate 38 and the second pressure plate 39 are configured so that the relative distance between them can be moved closer or farther away by the moving mechanism 36, but the relative distance between them may also be configured so that the relative distance between them can be moved closer or farther away by moving only one of the first pressure plate 38 and the second pressure plate 39.

[0063] In the above embodiment and modified examples, an example has been given in which the relative distance between the first feeder unit 61 and the second feeder unit 62 can be made to approach or move away by moving only the second feeder unit 62, but the relative distance between them can also be made to approach or move away by moving both the first feeder unit 61 and the second feeder unit 62.

[0064] In the above embodiment and modified example, the first pressure plate 38 and the second pressure plate 39 are configured to move in response to the movement of the first folding plate 26 and the second folding plate 27, but the present invention is not limited to this. For example, the first pressure plate 38 and the second pressure plate 39 may be driven and controlled to move away from each other in the left-right direction by the moving mechanism 36 that moves the first pressure plate 38 and the second pressure plate 39 toward and away from each other so as to pre-stretch the film F in the conveyance direction. In this case, the control device 9 may control the first folding plate 26 and the first pressure plate 38 to move synchronously, and the second folding plate 27 and the second pressure plate 39 to move synchronously. [Explanation of symbols]

[0065] 1...stretch wrapping device, 3...stretch mechanism, 6...film conveying mechanism (film conveying section), 9...control device (control section), 20...lift mechanism (lift section), 25...folding mechanism, 26...first folding plate (folding plate / clamp), 27...second folding plate (folding plate / clamp), 28...third folding plate, 31...support section, 32...up and down movement mechanism, 34...first arm, 35...second arm, 36...movement mechanism, 38...first pressure plate (clamp), 39...second pressure plate (clamp), 61...first feeder unit, 62...second feeder unit.

Claims

1. a film conveying section that conveys the film to a packaging area by clamping both sides of the film in a width direction perpendicular to the conveying direction; a lift unit that pushes up the film conveyed to the packaging area by moving the film upward from below while pressing a product against the film; a pair of folding plates that fold the peripheral portion of the film pushed up by the lift portion toward the bottom side of the product; A pair of clamps that respectively grip both ends of the film in the transport direction located below the pair of folding plates; a moving mechanism for moving the pair of clamps; A control unit that controls the movement of the movement mechanism, The control unit controls the moving mechanism to move at least one of the pair of clamps in a direction that increases the relative distance between the pair of clamps, thereby pre-stretching the film in the film conveying direction.

2. The pair of clamps includes the pair of folding plates and a pair of pressing plates that press the film from below on each of the pair of folding plates, The moving mechanism is configured to move the pressing plate in accordance with the movement of the folding plate, The control unit moves at least one of the folding plates in a state in which both ends of the film in the conveying direction are pressed against each of the folding plates by the pair of pressure plates in a direction in which the relative distance between the folding plates increases. A stretch wrapping device as described in claim 1.

3. the film transport section includes a pair of clamping units disposed opposite to each other in the width direction, The stretch wrapping device according to claim 1 or 2, wherein the control unit moves at least one of the pair of clamping units in a direction in which the relative distance between the clamping units increases before the film is pushed up by the product.

Images