Cutting device and bag-making filling packing machine

Abstract

To provide a cutting device that reliably cuts a belt-like medium with a simple configuration.SOLUTION: A cutting device includes: a cutter that cuts a belt-like medium; a pneumatic rotary actuator that generates rotational motion by supplying and discharging compressed air; and a crank mechanism that moves the cutter back and forth by converting the rotational motion of the pneumatic rotary actuator into linear motion and transmitting it to the cutter.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a cutting device that cuts a strip-shaped medium, and to a form-fill-seal machine equipped with the cutting device. [Background technology]

[0002] Background Art There has been known a form-fill-seal machine that includes a first sealing device that seals both ends of overlapping strip film, and a second sealing device that seals portions of the strip film formed into a cylindrical shape by the first sealing device that correspond to the top and bottom of a bag containing a product.

[0003] This type of bag form fill packaging machine is equipped with a cutter that appears and disappears from the heater block of the second sealing device to cut the borders of the bags that are continuously produced. The cutter can be driven, for example, by an air cylinder drive system or a motor (e.g., a servo motor or a stepping motor) drive system (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-301622 [Patent Document 2] JP 2015-205708 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the air cylinder drive system, the cutter accelerates suddenly from the start of operation and suddenly stops from top speed at the stroke end, which is different from the ideal cutter movement of slow start, acceleration, and slow down.

[0006] Furthermore, although the motor drive system can solve the problems associated with the air cylinder drive system, other problems arise, such as an increase in size and weight due to the inclusion of a speed reduction mechanism, an increase in the number of parts due to the inclusion of an origin sensor, and increased downtime due to the time it takes to identify the location of a malfunction. Furthermore, these problems can occur not only in form-fill-seal machines, but also in other devices that cut strip-shaped media.

[0007] The present invention has been made to solve the above-mentioned problems, and its object is to provide a technology for reliably cutting strip-shaped media with a simple configuration in a cutting device that reciprocates a cutter. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a cutting device for cutting strip-shaped media, comprising a cutter for cutting the media, a pneumatic rotary actuator that generates rotational motion by supplying and discharging compressed air, and a crank mechanism that converts the rotational motion of the pneumatic rotary actuator into linear motion and transmits it to the cutter, thereby moving the cutter back and forth. Effect of the Invention

[0009] According to the present invention, in a cutting device that reciprocates a cutter, it is possible to reliably cut a strip-shaped medium with a simple configuration. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is an overall perspective view of a vertical bag making, filling and packaging machine. [Diagram 2] FIG. 2 is a side view of a vertical form-fill-seal packaging machine. [Diagram 3] FIG. 13 is a diagram showing the cutter at its rearmost position. [Figure 4] FIG. 13 shows the cutter located at the contact position. [Diagram 5] FIG. 13 is a diagram showing the cutter at its forward limit. [Figure 6]5 is a diagram showing the relationship between the position of a solenoid valve and the rotation direction of a pneumatic rotary actuator. FIG. [Figure 7] FIG. 1 is a diagram showing the relationship between the rotation angle and the advance speed (A) and the position of the cutter at each point A to E (B). [Figure 8] FIG. 13 is a diagram showing a crank mechanism according to a first modified example. [Figure 9] FIG. 2 is a side view of a horizontal form-fill-seal packaging machine. [Figure 10] FIG. 2 is a plan view of a horizontal form-fill-seal packaging machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A vertical form fill and pack packaging machine 1 according to an embodiment will be described below with reference to the drawings. Note that the embodiment of the present invention described below is an example of how the present invention is embodied, and the scope of the present invention is not limited to the scope of the embodiment. Therefore, the present invention can be implemented by making various modifications to the embodiment.

[0012] Fig. 1 is an overall perspective view of a vertical form, fill and seal machine 1. Fig. 2 is a side view of the vertical form, fill and seal machine 1. The vertical form, fill and seal machine 1 (form, fill and seal machine) is a device that forms a strip-shaped film Fw (strip-shaped packaging material) into bags Bp and fills the formed bags Bp with products. The vertical form, fill and seal machine 1 mainly comprises a film supply device 10, a film feed device 20, a product filling tube 30, a vertical sealing device 40, a horizontal sealing device 50, and a control device 80.

[0013] The strip film Fw is a strip-shaped packaging material that is used to make bags for packaging products. The strip film Fw is a film-like member that can be welded by applying heat, and examples of the material include polyethylene (PE), polyethylene terephthalate (PET), biaxially oriented polypropylene (OPP), aluminum-lined paper, and aluminum-deposited paper. The product refers to granular foods such as candy, bean snacks, and snacks. However, specific examples of the product are not limited to these, and include any item that is packaged in a bag Bp and shipped.

[0014] Film supply device 10 is a device that transports strip film Fw wound around take-up roll 11 to film transport device 20. Film supply device 10 mainly includes take-up roll 11, multiple fixed guide rolls 12a-12h, a tension mechanism 13, and a cylinder former 14.

[0015] The winding roll 11 rotates in a direction to pay out the strip film Fw by being driven by the film feed device 20. The fixed guide rolls 12a-12h are arranged in the feed path of the strip film Fw from the winding roll 11 to the cylinder former 14, and guide the strip film Fw transported along the feed path. The tension mechanism 13 applies an appropriate tension to the strip film Fw transported along the feed path.

[0016] The cylinder former 14 overlaps both widthwise ends of the strip film Fw to form the strip film Fw into a cylindrical shape. The cylinder former 14 then sends the cylindrically formed strip film Fw downward toward the product filling tube 30. The strip film Fw formed into a cylindrical shape by the cylinder former 14 moves downward along the outer circumferential surface of the product filling tube 30.

[0017] A date printing device 15 and a date inspection device 16 are disposed opposite the feed path of the strip film Fw from the winding roll 11 to the tube former 14. The date printing device 15 prints dates (e.g., the manufacturing date, expiry date, best before date, etc.) at predetermined positions on the strip film Fw transported by the film supply device 10. The date inspection device 16 inspects whether the date has been properly printed by the date printing device 15.

[0018] The film feeding device 20 transports the strip film Fw transported by the film supply device 10 along a feed path that extends in the vertical direction. More specifically, the film feeding device 20 includes a pair of feed belts 21, 22 that face each other with the product filling tube 30 in between. A driving force of a motor (not shown) is transmitted to the pair of feed belts 21, 22, which feed the strip film Fw covering the outer circumferential surface of the product filling tube 30 downward toward the lateral sealing device 50. In this embodiment, the feed direction of the strip film Fw by the film feeding device 20 is downward.

[0019] The product filling cylinder 30 is a cylindrical member with an open top and bottom. The product filling cylinder 30 is disposed between the cylinder former 14 and the horizontal sealing device 50, and extends vertically along the feed direction of the strip-shaped film Fw formed into a cylindrical shape. A hopper 31 is attached to the top opening of the product filling cylinder 30. The product filling cylinder 30 fills the product, supplied through the hopper 31 from a combination weighing device (product supply device) (not shown), into bags Bp formed by the vertical sealing device 40 and the horizontal sealing device 50 through the bottom opening.

[0020] The vertical sealing device 40 is disposed in a position facing the product filling tube 30. More specifically, the vertical sealing device 40 is disposed downstream of the tube former 14 and upstream of the horizontal sealing device 50 in the feeding direction of the strip film Fw by the film feeding device 20.

[0021] The vertical sealing device 40 includes a pair of sealing blocks 41, 42 arranged to sandwich the overlapped ends of the strip film Fw. The pair of sealing blocks 41, 42 move toward and away from each other when the rotation of a motor is transmitted thereto. Each of the pair of sealing blocks 41, 42 has a built-in heater. The pair of sealing blocks 41, 42 sandwich and heat the overlapped ends of the strip film Fw, thereby welding (sealing) both ends in the width direction. As a result, the strip film Fw is formed into a cylindrical shape.

[0022] The horizontal sealing device 50 is disposed downstream of the vertical sealing device 40 in the feeding direction of the strip film Fw. The horizontal sealing device 50 forms the strip film Fw into bags Bp by welding (sealing) the cylindrically formed strip film Fw at predetermined intervals. More specifically, the horizontal sealing device 50 seals a portion of the strip film Fw formed into a cylindrical shape by the vertical sealing device 40 that corresponds to the top of the first bag Bp1 and a portion that corresponds to the bottom of the second bag Bp2 next to the first bag Bp1.

[0023] The horizontal sealing device 50 includes a pair of sealing blocks 51, 52. The pair of sealing blocks 51, 52 are disposed opposite each other, sandwiching the strip-shaped film Fw formed into a cylindrical shape by the vertical sealing device 40. A heater is built into each of the pair of sealing blocks 51, 52. The pair of sealing blocks 51, 52 come into contact with and separate from each other while sandwiching the strip-shaped film Fw. The pair of sealing blocks 51, 52 sandwich and heat the strip-shaped film Fw, thereby welding the strip-shaped film Fw.

[0024] FIG. 3 is a diagram showing the cutter 60 at the rear limit. FIG. 4 is a diagram showing the cutter 60 at the contact position. FIG. 5 is a diagram showing the cutter 60 at the forward limit. FIG. 6 is a diagram showing the relationship between the position of the solenoid valve 66 and the rotation direction of the pneumatic rotary actuator 64. FIG. 7 is a diagram showing the relationship between the rotation angle and the forward speed (A) and the position of the cutter 60 at each point A to E (B). Note that the seal block 52 and the block holder 56 are omitted from FIGS. 4 and 5. Also, in FIGS. 3 to 5 and 7, the stroke of the cutter 60 is exaggerated from the actual stroke in order to clarify the change in the position of the cutter 60.

[0025] As shown in Fig. 3, the horizontal sealing device 50 includes a pair of slide rods 53, 54 and a pair of block holders 55, 56. The pair of slide rods 53, 54 extend in the front-rear direction at positions spaced apart in the left-right direction. The pair of block holders 55, 56 are supported by the pair of slide rods 53, 54. The pair of block holders 55, 56 support the pair of seal blocks 51, 52.

[0026] The block holders 55 and 56 support the seal blocks 51 and 52 in a state where they face each other. More specifically, the seal block 51 is supported on the rear surface of the block holder 55, and the seal block 52 is supported on the front surface of the block holder 56. The block holder 55 is fixed to the front ends of the slide rods 53 and 54. Meanwhile, the block holder 56 is configured to be slidable in the front-rear direction along the slide rods 53 and 54. When the block holder 56 slides in the front-rear direction, the seal blocks 51 and 52 come close to each other and move away from each other.

[0027] As shown in Figures 3 to 6, the vertical bag making, filling and packaging machine 1 further includes a cutter 60, a cutter holder 61, a pair of slide rods 62a, 62b, stoppers 63a, 63b (buffer members), an air pressure rotary actuator 64, a compressor 65 (air pressure source), a solenoid valve 66, and a crank mechanism 67.

[0028] The cutter 60 cuts the sealed portion sealed by the horizontal sealing device 50 (more specifically, the boundary between the portion corresponding to the top of the first bag Bp1 and the portion corresponding to the bottom of the second bag Bp2). The front end of the cutter 60 forms a cutter blade 60a in which multiple peaks and valleys are arranged alternately in the left-right direction. In addition, the portion between the peaks and valleys of the cutter blade 60a is an inclined blade that is inclined with respect to the forward and backward movement direction of the cutter 60. The cutter blade 60a penetrates the strip-shaped film Fw, thereby cutting the strip-shaped film Fw.

[0029] The cutter 60 is accommodated inside the seal block 51 and the block holder 55 so as to be movable forward and backward. The cutter 60 appears and disappears from the rear surface of the seal block 51 (the surface that abuts against the seal block 52) when the seal blocks 51 and 52 are in contact with each other. The cutter 60 advances and retreats between the rear limit and the forward limit. The rear limit is the rearmost position of the movement range of the cutter 60. The forward limit is the frontmost position of the movement range of the cutter 60. The forward direction of the cutter 60 (the direction from the rear limit to the forward limit) coincides with the rear of the entire vertical form fill seal packaging machine 1. The rearward direction of the cutter 60 (the direction from the forward limit to the rear limit) coincides with the front of the entire vertical form fill seal packaging machine 1. However, these relationships are merely examples and are not limited to the above example.

[0030] As shown in Fig. 3, when the cutter 60 is at its rear limit, the cutter blade 60a is immersed in the seal block 51. Also, as shown in Fig. 4, when the cutter 60 advances from the rear limit and reaches the contact position, the peak of the cutter blade 60a comes into contact with the strip film Fw. When the cutter 60 advances further from the position shown in Fig. 4, the strip film Fw is cut by the inclined blade. Then, as shown in Fig. 5, the cutter 60 advances further to its forward limit after completely cutting the strip film Fw (i.e., the valley of the cutter blade 60a passes through the strip film Fw). Furthermore, the cutter 60 retreats from the forward limit shown in Fig. 5 to the rear limit shown in Fig. 3.

[0031] The cutter holder 61 supports the cutter 60. The pair of slide rods 62a, 62b are supported on the front surface of the block holder 55 (the surface opposite to the surface supporting the seal block 51). The pair of slide rods 62a, 62b are provided at positions spaced apart in the left-right direction, and each extends in the front-rear direction. The pair of slide rods 62a, 62b support the cutter holder 61 so that it can slide in the front-rear direction. That is, the cutter holder 61 moves (i.e., advances and retreats) in the front-rear direction together with the cutter 60 along the slide rods 62a, 62b.

[0032] The stoppers 63a and 63b are made of an elastically deformable material (e.g., urethane rubber). The stoppers 63a and 63b are fixed at predetermined positions in the front-rear direction of the slide rods 62a and 62b. More specifically, the stoppers 63a and 63b abut against a cutter holder 61 (an example of a member linearly moved by a crank mechanism 67) immediately before the cutter 60 reaches the retraction limit (in other words, the stroke end of a pneumatic rotary actuator 64 described later). Then, when the stoppers 63a and 63b abutting against the cutter holder 61 are elastically compressed, the cutter 60 reaches the retraction limit (in other words, the pneumatic rotary actuator 64 reaches the stroke end).

[0033] The pneumatic rotary actuator 64 generates a rotational motion by supplying and discharging compressed air supplied from a compressor 65. The rotation angle θ of the pneumatic rotary actuator 64 is set to 0° when the cutter 60 is located at the forward limit (in other words, when a first arm 68a and a second arm 68b described later extend linearly in the front-rear direction), and is set to -x° ≤ θ ≤ x°. In other words, the stroke ends of the pneumatic rotary actuator are set to -x° and x°. The value of x is set to 90° < x < 180°. In this embodiment, x = 135°.

[0034] The solenoid valve 66 is disposed on the passage of the compressed air from the compressor 65 to the pneumatic rotary actuator 64. The solenoid valve 66 is configured to be switchable between a first position A shown in FIG. 6(A) and a second position B shown in FIG. 6(B) according to the control of a control device 80. The initial position of the solenoid valve 66 is, for example, the first position A. Further, the solenoid valve 66 switches from the first position A to the second position B when a control signal is output from the control device 80 (hereinafter, expressed as "the control signal is ON"). Furthermore, the solenoid valve 66 switches from the second position B to the first position A when the output of the control voltage stops (hereinafter, expressed as "the control signal is OFF").

[0035] The first position A is a position of the solenoid valve 66 that supplies compressed air output from the compressor 65 in a direction that rotates the pneumatic rotary actuator 64 from -x° to x° in the counterclockwise direction in Fig. 6. The second position B is a position of the solenoid valve 66 that supplies compressed air output from the compressor 65 in a direction that rotates the pneumatic rotary actuator 64 from x° to -x° in the clockwise direction in Fig. 6. In other words, by switching the position of the solenoid valve 66, the rotation direction of the pneumatic rotary actuator 64 is reversed.

[0036] The crank mechanism 67 converts the rotational motion of the pneumatic rotary actuator 64 into linear motion (reciprocating motion) and transmits it to the cutter 60, thereby moving the cutter 60 forward and backward. The crank mechanism 67 according to this embodiment is a so-called "reciprocating slider crank mechanism." The crank mechanism 67 includes a first arm 68a, a second arm 68b, and pins 69a, 69b, and 69c. The first arm 68a and the second arm 68b are configured to be rotatable on a horizontal plane. The pins 69a to 69c are provided to extend in the vertical direction.

[0037] The pin 69a is disposed at the rotation center of the pneumatic rotary actuator 64 and rotates on its axis due to the rotational motion generated by the pneumatic rotary actuator 64. One end of the first arm 68a is fixed to the pin 69a (i.e., connected to the rotation center of the pneumatic rotary actuator 64) and rotates due to the rotational motion generated by the pneumatic rotary actuator 64. The other end (rotation tip) of the first arm 68a and one end of the second arm 68b are rotatably connected via the pin 69b. The other end of the second arm 68b is rotatably connected to the cutter holder 61 (i.e., the cutter 60 indirectly via the cutter holder 61) via the pin 69c.

[0038] The angle formed between the advancing and retracting direction of the cutter 60 and the first arm 68a is identical to the rotation angle θ of the pneumatic rotary actuator 64. Also, the pins 69a and 69c are always arranged on an imaginary line extending in the advancing and retracting direction of the cutter 60 (i.e., the front-back direction). And, as the pneumatic rotary actuator 64 rotates, the pin 69c reciprocates in a direction of approaching and separating from the pin 69a (i.e., the front-back direction). Thereby, the crank mechanism 67 converts the rotational motion of the pneumatic rotary actuator 64 into a linear motion of the pin 69c (more specifically, the cutter 60 fixed to the pin 69c via the cutter holder 61).

[0039] When the pneumatic rotary actuator 64 is positioned at one stroke end (θ = -135°) (Fig. 3) and a control signal ON is applied to the solenoid valve 66 (Fig. 6(B)), the cutter 60 is positioned at the retraction limit (point A in Fig. 7), and the cutter holder 61 elastically compresses the stoppers 63a and 63b. When the control signal to the solenoid valve 66 is turned OFF from this state (Fig. 6(A)), the pneumatic rotary actuator 64 starts to rotate counterclockwise.

[0040] As shown in Figs. 3 to 5 and Fig. 7, as the rotation angle θ of the pneumatic rotary actuator 64 rotates from -135° to 0°, the cutter 60 advances from the retraction limit (point A in Fig. 7) to the advancement limit (point E in Fig. 7). Also, as shown in Figs. 6(A) and 7(A), in the range of -135° ≤ θ ≤ 0°, the first half part is an acceleration section where the cutter 60 advances while accelerating, and the remaining second half part is a deceleration section where the cutter 60 advances while decelerating. The acceleration section is the section from the stroke end of the pneumatic rotary actuator 64 to a predetermined rotation angle -y°, and the deceleration section is the section from the end of the acceleration section to the rotation angle θ = 0°.

[0041] Note that the predetermined rotation angle -y° is a value that varies depending on conditions such as the operating characteristics of the pneumatic rotary actuator 64, the length of the first arm 68a, and the length of the second arm 68b. Also, the predetermined rotation angle -y° is a value in the range of -135° < -y° < 0°. Furthermore, the predetermined rotation angle y° is a value in the range of 0° < y° < 135°.

[0042] That is, the cutter 60 stopped at the backward limit advances while accelerating in the acceleration section as the pneumatic rotary actuator 64 rotates between -135°≦θ≦0°, reaches the maximum forward speed at a predetermined rotation angle -y°, and then decelerates in the deceleration section to reach the forward limit. Furthermore, the cutter 60 that has reached the forward limit advances while accelerating in the acceleration section as the pneumatic rotary actuator 64 rotates between 0°≦θ≦135°, reaches the maximum backward speed at a predetermined rotation angle y°, and then decelerates in the deceleration section to return to the backward limit. That is, the cutter 60 moves from the backward limit to the forward limit via the forward limit while the pneumatic rotary actuator 64 rotates from one stroke end (θ=-135°) to the other stroke end (θ=135°) (i.e., makes a round trip between the backward limit and the forward limit).

[0043] 6 before the forward speed reaches its maximum value (i.e., before reaching the end of the acceleration section). That is, the cutter 60 punches holes in the strip film Fw at multiple peaks before the forward speed reaches its maximum value, cuts the strip film Fw with the inclined blade while accelerating, merges the cutting lines at multiple valleys while decelerating, and then stops at the forward limit.

[0044] More specifically, as shown by point B in Fig. 7, in the first half of the acceleration section where the forward speed is sufficiently slow, the tip of the cutter 60 gently penetrates the strip film Fw. Also, as shown by point C in Fig. 7, when the forward speed of the cutter 60 reaches its maximum value, the center part of the cutter blade 60a penetrates the strip film Fw. Thereafter, the cutter 60 advances while decelerating, and at point D in Fig. 7 where the forward speed has sufficiently slowed down, the valley part of the cutter blade 60a reaches the strip film Fw and cuts the strip film Fw so that the penetrated surfaces are gently connected. Then, as shown by point E in Fig. 7, the cutter 60 gently decelerates and stops at the forward limit.

[0045] 7(A), point A corresponds to a rotation angle θ=-135°, and point E corresponds to a rotation angle θ=0°. The speed of the cutter 60 in the section -135°≦θ≦0° in which the cutter advances from the backward limit to the forward limit changes in the direction from point A to E. On the other hand, the speed of the cutter 60 in the section 0°≦θ≦135° in which the cutter advances from the forward limit to the backward limit changes in the direction from point E to A.

[0046] Then, just before (for example, θ=134°) the cutter 60 reaches the rearward limit (i.e., the rotation angle θ of the pneumatic rotary actuator 64=135°), the cutter holder 61, whose rearward speed has slowed sufficiently, gently abuts against the stoppers 63a, 63b. Then, the cutter holder 61 moves rearward while elastically compressing the stoppers 63a, 63b, and the cutter 60 reaches the rearward limit (i.e., the other stroke end of the pneumatic rotary actuator 64).

[0047] Similarly, when the pneumatic rotary actuator 64 is at the other stroke end (θ=135°) and the control signal to the solenoid valve 66 is OFF (FIG. 6(A)), the cutter 60 is at the rearmost position and the cutter holder 61 elastically compresses the stoppers 63a, 63b. When the control signal to the solenoid valve 66 is turned ON from this state (FIG. 6(B)), the pneumatic rotary actuator 64 starts to rotate clockwise. The behavior of the cutter 60 at this time is the left-right reverse of when the pneumatic rotary actuator 64 rotates counterclockwise.

[0048] The control device 80 includes, for example, a central processing unit (CPU) that is a calculation means, and a memory that is a storage means. The memory is, for example, a read only memory (ROM) that stores various programs, a random access memory (RAM) that is a working area for the calculation means, a hard disk drive (HDD), or a combination of these. The CPU reads and executes the programs stored in the memory to realize each process described below. However, the specific configuration of the control device 80 is not limited to this, and may be realized by hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0049] The control device 80 repeatedly performs the process of forming a bag Bp from the strip film Fw and filling it with the product by operating the film supply device 10, the film feed device 20, the vertical sealing device 40, the horizontal sealing device 50, and the solenoid valve 66 in conjunction with each other.

[0050] First, the control device 80 drives the film supply device 10 and the film feed device 20 to feed the strip film Fw in the feed direction by an amount corresponding to the height of one bag Bp. Next, the control device 80 drives the vertical sealing device 40 to sandwich and seal the overlapped ends of the strip film Fw between a pair of seal blocks 41, 42, thereby forming the strip film Fw into a cylindrical shape.

[0051] The control device 80 also seals the portion of the strip film Fw formed into a cylindrical shape, which corresponds to the top of the first bag Bp1, and the portion of the strip film Fw which corresponds to the bottom of the second bag Bp2 immediately behind the first bag Bp1, by sandwiching them between the seal blocks 51 and 52. Furthermore, the control device 80 cuts the boundary between the adjacent bags Bp1 and Bp2 by switching a control signal to the solenoid valve 66 between ON and OFF. More specifically, when cutting between the top of the first bag Bp1 and the bottom of the second bag Bp2, the control device 80 switches the control signal to the solenoid valve 66 from ON to OFF. When cutting between the top of the second bag Bp2 and the bottom of the third bag Bp3, the control device 80 switches the control signal to the solenoid valve 66 from OFF to ON.

[0052] According to the above embodiment, for example, the following advantageous effects are achieved.

[0053] According to the above embodiment, by moving the cutter 60 back and forth with the pneumatic rotary actuator 64, the boundary portion between adjacent bags can be reliably cut with a simple configuration compared to a motor-driven system. In addition, the tip of the cutter 60 gently penetrates the strip film Fw, and when the valley portion of the cutter blade 60a reaches the strip film Fw, the cutter blade 60a can cut the strip film Fw so that the penetrated surfaces of the strip film Fw are gently connected to each other, improving the aesthetic appearance of the boundary portion between adjacent bags Bp. Furthermore, damage to the cutter blade 60a when cutting the strip film Fw can be reduced, contributing to a longer life of the cutter 60.

[0054] More specifically, since the pneumatic rotary actuator 64 can generate a large torque, a reduction mechanism can be omitted compared to a motor-driven system. As a result, this contributes to a reduction in size and weight of the vertical form-fill-seal packaging machine 1. Also, since it is only necessary to rotate the pneumatic rotary actuator 64 to the stroke end, an origin sensor and the like can be omitted. As a result, an increase in the number of parts in the vertical form-fill-seal packaging machine 1 can be prevented. Furthermore, since a fault location can be easily identified in the power transmission path from the compressor 65, the solenoid valve 66, the pneumatic rotary actuator 64, and the crank mechanism 67 to the cutter 60, an increase in downtime of the vertical form-fill-seal packaging machine 1 can be prevented.

[0055] Furthermore, according to the above embodiment, the rotation angle x of the pneumatic rotary actuator 64 from the rear limit until the cutter 60 reaches the forward limit is set to a value greater than 90°, thereby expanding the options for the rotation angle θ when the tip of the cutter 60 reaches the contact position. Therefore, the tip of the cutter 60 can be brought into contact with the strip film Fw at the timing when the torque is greatest.

[0056] Furthermore, according to the above embodiment, by rotating the pneumatic rotary actuator 64 from one stroke end to the other stroke end, the cutter 60 can be reliably moved back and forth between the backward limit and the forward limit, so that the strip film Fw can be reliably cut. Also, since there is no need to move the cutter 60 back and forth an extra distance to reliably cut the strip film Fw, the cutter 60 can be moved back and forth with ample margin.

[0057] Also, according to the above embodiment, by switching ON / OFF of the control signal for the solenoid valve 66, the pneumatic rotary actuator 64 can be rotated from one stroke end to the other stroke end (i.e., the cutter 60 can be made to make one reciprocating motion). As a result, the number of times the solenoid valve 66 needs to be switched can be halved compared to an air cylinder drive system, which contributes to extending the life of the solenoid valve 66. Furthermore, air consumption is halved compared to a case where a direct acting pneumatic actuator is used.

[0058] Furthermore, according to the above embodiment, the cutter holder 61 is brought into contact with the stoppers 63a, 63b immediately before the pneumatic rotary actuator 64 reaches the stroke end, thereby mitigating the impact when the pneumatic rotary actuator 64 reaches the stroke end. This reduces the operating noise of the vertical form fill pack packaging machine 1 and suppresses damage to the components.

[0059] [Variation 1] Another example of the crank mechanism 67 will be described with reference to Fig. 8. Fig. 8 is a diagram showing a crank mechanism 67A according to Modification 1. Note that detailed description of commonalities with the above embodiment will be omitted, and differences will be mainly described.

[0060] The crank mechanism 67A according to the first modification is common to the crank mechanism 67 according to the above embodiment in that it converts the rotational motion of the pneumatic rotary actuator 64 into linear motion (reciprocating motion) and transmits it to the cutter 60. On the other hand, as shown in Fig. 8, the crank mechanism 67A according to the first modification is different from the crank mechanism 67 according to the above embodiment in that it includes a plate cam 70 instead of the second arm 68b and the pin 69c. In other words, the crank mechanism 67A according to the first modification is a so-called "reciprocating double slider crank mechanism (Scotch yoke)" that includes a first arm 68a (arm), pins 69a, 69b, and a plate cam 70.

[0061] The plate cam 70 is a flat plate-shaped member. A cam groove 71 that accommodates the pin 69a is formed in the plate cam 70. The cam groove 71 extends in a direction perpendicular to the forward and backward movement direction of the cutter 60 (i.e., the left-right direction). The cam groove 71 may penetrate the plate cam 70 in the thickness direction, or may be a recess provided on the surface of the plate cam 70 that faces the pin 69a. The plate cam 70 is connected to the cutter 60 via the cutter holder 61.

[0062] As shown in FIG. 8, when the cutter 60 is at the rear end (in other words, the rotation angle θ of the pneumatic rotary actuator 64 is -x°), the pin 69b is located on one side of the center of the extension direction of the cam groove 71. Then, as the pneumatic rotary actuator 64 rotates from θ=-135° to 0°, the pin 69b moves in the cam groove 71 toward the center of the extension direction and presses the plate cam 70 forward. This causes the cutter 60 to move forward. Then, when the cutter 60 reaches the forward end (in other words, the rotation angle θ of the pneumatic rotary actuator 64 is 0°), the pin 69b is located in the center of the extension direction of the cam groove 71. Furthermore, as the pneumatic rotary actuator 64 rotates from θ=0° to 135°, the pin 69b moves in the cam groove 71 toward the other side of the extension direction and presses the plate cam 70 backward. This causes the cutter 60 to move backward. When the cutter 60 reaches the rear limit (in other words, the rotation angle θ of the pneumatic rotary actuator 64=x°), the pin 69b is offset to the other side from the center of the cam groove 71 in the extension direction.

[0063] [Variation 2] Another example of a form-fill-seal packaging machine will be described with reference to Figures 9 and 10. Figure 9 is a side view of a horizontal form-fill-seal packaging machine 100. Figure 10 is a plan view of the horizontal form-fill-seal packaging machine 100. The horizontal form-fill-seal packaging machine 100 is a device that packages products P supplied from a supply device (not shown) one by one. As shown in Figures 9 and 10, the horizontal form-fill-seal packaging machine 100 mainly includes a supply conveyor 110, a film feed device 120, a clamping and conveying device 130, a center seal device 135 (first sealing device), and an end seal device 140 (second sealing device).

[0064] The supply conveyor 110 supplies products P, which are sequentially supplied from a supply device (not shown), to the cylinder former 126. As shown in Fig. 9, the supply conveyor 110 is made up of a drive sprocket 114, a driven sprocket 115, an endless circular conveyor chain 116 stretched around the drive sprocket 114 and the driven sprocket 115, and a drive motor 117 that drives the drive sprocket 114.

[0065] Further, the conveyor chain 116 is provided with a plurality of pushers 118. The plurality of pushers 118 are arranged at predetermined intervals in the conveying direction of the product P. The product P supplied from the supply device enters between two adjacent pushers 118. The pushers 118 come into contact with the rear end of the product P to push the product P.

[0066] The film feeding device 120 feeds the strip film Fw toward the clamping and conveying device 130. As shown in Figures 9 and 10, the film feeding device 120 mainly includes a winding shaft 121 around which the strip film Fw is wound, a driving roller 122, a driven roller 123, a feed motor 124, guide rollers 125a and 125b, and a cylinder former 126.

[0067] The drive roller 122 and the driven roller 123 rotate with the strip film Fw sandwiched between them. The drive roller 122 rotates when the driving force of the feed motor 124 is transmitted to it. This causes the drive roller 122 and the driven roller 123 to pay out the strip film Fw wound around the winding shaft 121 toward the tube former 126. The guide rollers 125a, 125b are disposed along the transport path of the strip film Fw from the winding shaft 121 through the drive roller 122 and driven roller 123 to the tube former 126, and apply tension to the strip film Fw as it is paid out.

[0068] The cylinder former 126 forms the strip film Fw fed by the film feed device 120 into a cylindrical shape, and serves as an entrance through which the product P fed from the supply conveyor 110 enters the cylindrical strip film Fw. The cylinder former 126 is disposed on the transport path of the strip film Fw from the film feed device 120 to the center seal device 135. The cylinder former 126 is disposed facing the downstream end of the supply conveyor 110 in the transport direction.

[0069] The strip film Fw fed by the film feed device 120 is formed into a cylindrical shape by overlapping both ends in the width direction perpendicular to the conveying direction below as it moves along the cylinder former 126. In addition, the product P supplied from the supply conveyor 110 passes through the internal space of the cylinder former 126 and enters the inside of the cylindrical strip film Fw.

[0070] The clamping and conveying device 130 clamps the overlapped ends of the strip film Fw formed into a cylindrical shape by the cylinder former 126, and conveys it in the conveying direction. The clamping and conveying device 130 is disposed downstream in the conveying direction from the cylinder former 126. The clamping and conveying device 130 is also disposed below the strip film Fw and product P that have passed through the cylinder former 126. The clamping and conveying device 130 mainly comprises a support plate 131, a pair of film feed rollers 132, 133, and a feed motor 134.

[0071] The support plate 131 is connected downstream in the conveying direction from the cylinder former 126. The support plate 131 supports the product P contained in a cylindrical strip film Fw. The support plate 131 also extends in the conveying direction to the position of the center seal device 135. Furthermore, the support plate 131 is provided with a slit 139 that extends in the widthwise center along the conveying direction of the strip film Fw. The overlapped ends of the strip film Fw protrude from the underside of the support plate 131 through the slit 139.

[0072] The pair of film feed rollers 132, 133 are disposed on the underside of the support plate 131. The pair of film feed rollers 132, 133 clamp the overlapped ends of the strip film Fw protruding through the slit 139. The film feed rollers 132, 133 are rotated by the driving force of the feed motor 134. As a result, the cylindrical strip film Fw is transported in the transport direction toward the center seal device 135.

[0073] The center seal device 135 seals both widthwise ends of the strip film Fw that has been overlapped by the cylinder former 126. The center seal device 135 is disposed downstream in the conveying direction from the cylinder former 126 and the clamping and conveying device 130. The center seal device 135 is also disposed below the strip film Fw and the product P (in other words, the support plate 131). The center seal device 135 mainly comprises a pair of seal rollers 136, 137 and a seal motor 138.

[0074] The pair of sealing rollers 136, 137 are disposed on the underside of the support plate 131, downstream of the film feed rollers 132, 133 in the transport direction of the strip film Fw. The pair of sealing rollers 136, 137 clamp the overlapped end of the strip film Fw protruding through a slit 139. The outer circumferential surfaces of the sealing rollers 136, 137 are heated by a heater (not shown). The sealing roller 136 is rotated by the driving force of a sealing motor 138 transmitted thereto. This causes the overlapped end of the strip film Fw clamped between the sealing rollers 136, 137 to be sealed (welded).

[0075] The end sealing device 140 is disposed downstream in the conveying direction of the cylinder former 126, the clamping and conveying device 130, and the center sealing device 135. The end sealing device 140 seals the cylindrical strip film Fw sealed by the center sealing device 135 on both sides of the product P in the conveying direction to form a bag Bp containing the product P. The end sealing device 140 mainly includes a pair of sealing blocks 141, 142, and a contact / separation motor 143.

[0076] The pair of sealing blocks 141, 142 are arranged vertically, sandwiching the strip film Fw formed into a cylindrical shape. The surfaces of the pair of sealing blocks 141, 142 facing the strip film Fw are heated by a heater (not shown). The pair of sealing blocks 141, 142 are brought into contact with and separated from each other by the driving force of a contact and separation motor 143. The end seal device 140 brings the pair of sealing blocks 141, 142 into contact with each other between adjacent products P. As a result, the portions of the strip film Fw sandwiched between the sealing blocks 141, 142 between the adjacent products P are sealed (welded).

[0077] Furthermore, horizontal form-fill-seal packaging machine 100 further includes a cutter 60, a cutter holder 61, a pair of slide rods 62a, 62b, stoppers 63a, 63b, an air pressure rotary actuator 64, a compressor 65 (air pressure source), a solenoid valve 66, and a crank mechanism 67. More specifically, cutter 60 according to modification 2 may protrude from and retract into seal block 141. In this case, the forward direction of cutter 60 coincides with the downward direction of the entire horizontal form-fill-seal packaging machine 100, and the backward direction of cutter 60 coincides with the upward direction of the entire horizontal form-fill-seal packaging machine 100.

[0078] [Variation 3] Furthermore, the present invention can be conceived as a cutting device including at least the cutter 60, the pneumatic rotary actuator 64, and the crank mechanism 67. The cutting device may further include some or all of the cutter holder 61, the pair of slide rods 62a, 62b, the stoppers 63a, 63b, the compressor 65, and the solenoid valve 66.

[0079] The cutting device is a device that cuts a strip-shaped medium. The strip-shaped film Fw is an example of a strip-shaped medium. The cutting device may cut an arbitrary position of a strip-shaped adhesive tape, or a boundary portion between a plurality of bags connected in a strip shape, each containing an oxygen absorber, as another example of a strip-shaped medium. Furthermore, the cutting device may be installed not only in the vertical form-fill-seal packaging machine 1 and the horizontal form-fill-seal packaging machine 100, but also in a boxing machine, a box-making machine, a box-sealing machine, an oxygen absorber supplying device, etc. [Explanation of symbols]

[0080] 1...vertical bag making, filling and packaging machine, 10...film supply device, 11...winding roll, 12a-12h...fixed guide roll, 13...tension mechanism, 14,126...tube maker, 15...date printing device, 16...date inspection device, 20...film feed device, 21,22...feed belt, 30,126...product filling tube, 31...hopper, 40...vertical sealing device, 41,42,51,52,141,142...seal block, 50...horizontal sealing device, 53,54,62a,62b...slide rod, 55,56...block holder, 60...cutter, 60a...cutter blade, 61...cutter holder, 63a,63b...stopper, 64...pneumatic rotary actuator, 65...compressor, 66...solenoid valve, 67,67A...crank mechanism, 68a...first First arm, 68b...second arm, 69a-69c...pin, 70...plate cam, 71...cam groove, 80...control device, 100...horizontal form-fill-seal packaging machine, 110...supply conveyor, 114...driving sprocket, 115...driven sprocket, 116...conveyor chain, 117...driving motor, 118...pusher, 120...film feed device, 121...winding shaft, 122...driving roller, 123...driven roller, 124, 134...feed motor, 125a, 152b...guide roller, 130...clamping conveyor, 131...support plate, 132, 133...film feed roller, 135...center seal device, 136, 137...seal roller, 138...seal motor, 139...slit, 140...end seal device, 143...contact / separation motor

Claims

1. A cutting device for cutting a strip of media, a cutter for cutting the medium; a pneumatic rotary actuator that generates rotational motion by supplying and discharging compressed air; a crank mechanism for converting the rotational motion of the pneumatic rotary actuator into linear motion and transmitting the linear motion to the cutter, thereby moving the cutter back and forth.

2. 2. The cutting device according to claim 1, The crank mechanism includes: A first arm that is connected to a rotation center of the pneumatic rotary actuator and rotates; a second arm having one end rotatably connected to the rotation tip of the first arm and the other end rotatably connected to the cutter, The cutter reciprocates between a rear limit at which the cutter is most rearward and a front limit at which the cutter is most forward, a rotation angle θ of the pneumatic rotary actuator is set to −x°≦θ≦x°, with 0° being the angle when the cutter is located at the forward limit; A cutting device, wherein the value of x is 90°<x<180°.

3. 3. The cutting device according to claim 2, The cutting device according to claim 1, wherein the cutter moves from the rearward limit to the forward limit and then back to the rearward limit while the pneumatic rotary actuator rotates from one of -x° and x° to the other.

4. 4. The cutting device according to claim 3, A cutting device according to claim 1, wherein the tip of the cutter contacts the media before the forward speed reaches a maximum value.

5. 4. The cutting device according to claim 3, a first position for supplying compressed air in a direction to rotate the pneumatic rotary actuator from -x° to x°, and a second position for supplying compressed air in a direction to rotate the pneumatic rotary actuator from x° to -x°.

6. 3. The cutting device according to claim 2, 13. A cutting device according to claim 12, further comprising a buffer member that abuts against a member linearly moved by the crank mechanism before the pneumatic rotary actuator reaches a stroke end, and elastically compresses the member to allow the pneumatic rotary actuator to reach the stroke end.

7. 2. The cutting device according to claim 1, The crank mechanism includes: an arm that is connected to a rotation center of the pneumatic rotary actuator and rotates; a plate cam having a cam groove that receives a pin provided at a rotation tip of the arm and extends in a direction perpendicular to the advancement and retreat of the cutter, and that advances and retreats in accordance with the rotation of the arm; The cutter connected to the plate cam reciprocates between a rear limit at which the cutter is most rearward and a forward limit at which the cutter is most forward, a rotation angle θ of the pneumatic rotary actuator is set to −x°≦θ≦x°, with 0° being the angle when the cutter is located at the forward limit; A cutting device, wherein the value of x is 90°<x<180°.

8. A form-fill-seal packaging machine that fills products into bags formed from a strip-shaped packaging material as a medium, a cylinder former for overlapping both widthwise ends of the strip-shaped packaging material to form it into a cylindrical shape; a first sealing device for sealing both ends of the strip-shaped packaging material overlapped by the tube former; a second sealing device for sealing the portions of the strip-shaped packaging material formed into a cylindrical shape by the first sealing device, the portions corresponding to the top and bottom of a bag containing a product; 2. A form-fill-seal packaging machine comprising: a cutting device according to claim 1 which cuts the sealed portion of the strip-shaped packaging material sealed by the second sealing device.

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