Heat sealing device

Abstract

To provide a heat sealing device that can reduce processing defects in the sealing portion. [Solution] The sealing device 1 includes a pressing section 55 having a rectangular pressing surface 55a, a receiving section 65 having a receiving surface 65a that sandwiches and receives a workpiece W, which is made up of at least two overlapping film members, between the pressing section 55 and the pressing surface 55a, a plurality of springs 56 provided on either the pressing section 55 or the receiving section 65 and arranged along the longitudinal direction of the pressing section 55 in an area on both sides outside the pressing surface 55a in the shorter direction when viewed from the pressing direction, which is the direction of pressing, and a conductor 66 that heats and welds the workpiece W sandwiched between the pressing section 55 and the receiving section 65 in a linear area along the longitudinal direction of the pressing section 55.

Description

Technical Field

[0001] The present invention relates to a heat sealing apparatus that partially heat-seals a workpiece.

Background Art

[0002] Conventionally, there has been a heat sealing apparatus that heat-seals a part of workpieces stacked in two or more layers to manufacture, for example, bags and the like as processed products (for example, Patent Document 1). However, the conventional heat sealing apparatus has problems such as unstable processing of the sealed portion (e.g., partial non-welding).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] An object of the present invention is to provide a heat sealing apparatus that can reduce processing defects in the sealed portion of a workpiece.

Means for Solving the Problem

[0005] One aspect of the present invention is, for example, a heat sealing apparatus comprising: a pressing part having a rectangular pressing surface; a receiving part having a receiving surface for receiving a workpiece in which at least two film members are stacked, with the workpiece sandwiched between the receiving surface and the pressing surface of the pressing part; a plurality of elastic support parts provided on any one of the pressing part and the receiving part, and arranged along the longitudinal direction of the pressing part in ranges on both sides in the lateral direction of the pressing part when viewed from the pressing direction that is the direction of pressing; and a heat generating part that heats and welds the workpiece sandwiched between the pressing part and the receiving part in a linear range along the longitudinal direction of the pressing part.

Brief Description of the Drawings

[0006] [Figure 1] This is a view of the sealing device 1 of the embodiment from three directions. [Figure 2] This is a perspective view illustrating the workpiece W and bag W1 of the embodiment. [Figure 3] This figure shows the slide shaft 15 of the embodiment positioned at the upper end of the total stroke (sum of the air-driven stroke and the crank stroke). [Figure 4] This figure shows the slide shaft 15 of the embodiment positioned at the bottom of the air-driven stroke and the top of the crank stroke. [Figure 5] This figure shows the slide shaft 15 of the embodiment positioned at the lower end of the total stroke. [Figure 6] This diagram illustrates the configuration of the vicinity of the upper unit 50 and the lower unit 60 in the embodiment. [Figure 7] This diagram illustrates the operation of the sealing device 1 of the embodiment, and shows the positional relationship of the upper unit 50 and the lower unit 60 as viewed from the right side X2. [Figure 8] This diagram illustrates the operation of the sealing device 1 of the embodiment, and shows the positional relationship of the upper unit 50 and the lower unit 60 as viewed from the right side X2. [Figure 9] This diagram illustrates the operation of the sealing device 1 of the embodiment, and shows the positional relationship of the upper unit 50 and the lower unit 60 as viewed from the right side X2. [Figure 10] This diagram illustrates the positional relationship between the workpiece W, the pressing portion 55, etc., of the embodiment, as viewed from above Z2. [Modes for carrying out the invention]

[0007] (Embodiment) Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings and other documents. Figure 1 shows the sealing device 1 of the embodiment viewed from three directions. Figure 1(A) is a view of the sealing device 1 from above, Z2. Figure 1(B) is a schematic diagram showing a cross-section of the sealing device 1 as viewed from the front Y1. Figure 1(C) is a schematic diagram showing a cross-section of the sealing device 1 as viewed from the right side X2. Figure 2 is a perspective view illustrating the workpiece W and bag W1 of the embodiment. Figure 2(A) shows the workpiece W as viewed from above at Z2. Figure 2(B) shows the workpiece W as viewed from the front Y1. Figure 2(C) shows the workpiece W as viewed from the right side X2. Figure 2(D) is a perspective view of the workpiece W. Figure 2(E) is a perspective view illustrating the laminated structure of the workpiece W. Figures 3 to 5 schematically show cross-sections of the sealing device 1 of the embodiment as viewed from the front Y1 and the right side X2, respectively. Figures 3 to 5 show the movement of the slide shaft 15 from the top to the bottom. Figure 3 shows the slide shaft 15 positioned at the upper end of the total stroke (sum of air-driven stroke and crank stroke). Note that Figures 3(A) and 3(B) are the same as Figures 1(B) and 1(C), and are enlarged versions of Figures 1(B) and 1(C). Figure 4 shows the slide shaft 15 positioned at the bottom of the air-driven stroke and the top of the crank stroke. Note that the state in Figure 4 represents the top dead center position of the crank drive unit 20 when the seal device 1 is in operation. Figure 5 shows the slide shaft 15 positioned at the lower end of its total stroke. Note that the state in Figure 5 represents the bottom dead center state of the crank drive unit 20 when the seal device 1 is in operation. Figure 6 is a diagram illustrating the configuration of the vicinity of the upper unit 50 and the lower unit 60 in the embodiment. Figure 6(A) is a view from the upper side Z2. Figure 6(B) is a view from the front Y1. Figures 7 to 9 illustrate the operation of the sealing device 1 of the embodiment, and show the positional relationship of the upper unit 50 and the lower unit 60 as viewed from the right side X2. FIG. 7(A) shows a state where the upper unit 50 is arranged at the upper end of the total stroke. FIG. 7(B) is a diagram showing a top dead center state (the lowest position of the air drive stroke and the highest position of the crank stroke). FIG. 8(A) is a diagram showing a process of transitioning from the top dead center state to the bottom dead center state (a state where the pressing surface 55a and the receiving surface 65a start to abut with the workpiece W sandwiched therebetween). FIG. 8(B) is a diagram showing a bottom dead center state. FIG. 9 is a diagram showing a state in which the bag body W1 after sealing processing according to the embodiment is delivered, and the workpiece W for the next sealing processing is loaded.

[0008] In the embodiment and the drawings, for convenience, description is given with an XYZ orthogonal coordinate system provided. As shown in FIG. 1 and the like, this coordinate system represents the left-right direction X (left side X1, right side X2), the front-rear direction Y (front side Y1, rear side Y2), and the vertical direction Z (lower side Z1, upper side Z2) of the sealing device 1. Further, in the drawings, for portions integrally configured by combining a plurality of components, illustration of boundary lines between the components is appropriately omitted in order to clearly show aspects such as integral movement.

[0009] As shown in FIG. 1 and FIG. 2, the sealing device 1 (heat sealing device) is an apparatus that manufactures the bag body W1 by heat-sealing the sealing range W10a which is the side portions (edge portions) on the front side Y1 and the rear side Y2 of the workpiece W while feeding the workpiece W in the feeding direction, and performing fusing (cutting by melting). The feeding direction of the workpiece W is the direction from the front side Y1 toward the rear side Y2, with the front side Y1 being the upstream side and the rear side Y2 being the downstream side. Although detailed description of the feeding device that feeds the workpiece W is omitted, for example, at the timing when the workpiece W is pressed and heat-sealed by the pressing portion 55 and the receiving portion 65, control such as temporarily stopping the feeding of the workpiece W is performed. In FIG. 1(C), the feeding device 2 that feeds the workpiece W into the processing position and the feeding device 3 that feeds the processed bag body W1 from the processing position to the outside are illustrated in a simplified manner. These feeding devices 2, 3 include, for example, rollers, belts and the like. In drawings other than FIG. 1(C), illustration of the feeding devices 2, 3 is omitted.

[0010] As shown in Figure 2, the workpiece W is, for example, a sheet material folded in two. As shown in Figure 2(E) and the like, in the embodiment, an example will be described in which the sheet material is a bubble sheet material W10. The bubble sheet material W10 is formed by laminating a cap film W11 and a back film W12. These layers are joined together by thermal welding or the like. The cap film W11 and the back film W12 are, for example, resin films such as polyethylene, polypropylene, and polyethylene terephthalate, but are not limited thereto, and may be any resin film that can be thermally welded.

[0011] The bubble sheet material W10 can be used alone as a bubble cushioning material or the like (see, for example, Japanese Unexamined Patent Application Publication No. 07-016965 and the like). In the embodiment, an example will be described in which the workpiece W is the bubble sheet material W10 folded in two such that the cap film W11 is on the inner side and the back film W12 is on the outer side, but the back film W12 may be on the inner side and the cap film W11 on the outer side. Further, the bubble sheet material W10 may be a product in which a further flat film (also referred to as a liner film or the like) is laminated on the cap film W11.

[0012] The cap film W11 includes a plurality of convex-shaped caps W11a that bulge out in a hollow form. By laminating the back film W12 on the cap film W11, air is enclosed inside the plurality of caps W11a. As shown in Figure 2(B), in the embodiment, the workpiece W after processing is a bag body W1 with an opening at the right side portion. The left side portion of the bag body W1 is the folded portion from the two-fold, and the edge of the upper side portion and the edge of the lower side portion are each thermally welded by the sealing device 1. Thereby, the shape of the bag body W1 after processing is such that the left side portion, the upper side portion, and the lower side portion are closed, and the right side portion is open.

[0013] The bag body W1 can be used as a bag-shaped cushioning material that protects an article by storing the article therein, but is not limited thereto, and can be used for various applications.

[0014] As shown in Figures 1 and 3, the sealing device 1 comprises a base 10, a slide shaft 15, a crank drive unit 20 (second drive unit), an air drive unit 30 (first drive unit), an upper unit 50 (first unit), and a lower unit 60 (second unit). The base 10 is the base portion of the sealing device 1. The base 10 comprises a table 11 and legs 12. The table 11 is arranged parallel to the horizontal plane (XY plane). The legs 12 support the table 11. The legs 12 make contact with the mounting surface of the sealing device 1. The slide shaft 15 is a shaft driven by a crank drive unit 20 and an air drive unit 30 to reciprocate in the vertical direction Z. The axial direction of the slide shaft 15 is parallel to the vertical direction Z. The upper end of the slide shaft 15 is fixed to the four corners of the upper plate 51 (described later) of the upper unit 50 (see Figure 6, etc.).

[0015] (Crank drive unit 20) The crank drive unit 20 converts the rotational motion of the motor 23 into the linear motion of the moving table 26. The crank drive unit 20 includes a motor fixing plate 21, a motor 23, a crankshaft 25, a moving table 26, and an arm 28. The motor fixing plate 21 is a rectangular plate for fixing the motor 23. The motor fixing plate 21 is positioned parallel to the horizontal plane in a range Z1 below the table 11. The four corners of the motor fixing plate 21 are connected to the table 11 by support rods 22 (see Figure 3(A), etc.). In this way, the motor fixing plate 21 is supported as if suspended from the table 11.

[0016] The outer circumference of the support rod 22 is provided with a male screw, and the mounting position of the motor fixing plate 21 to the support rod 22 can be adjusted with a nut, thereby allowing for fine adjustment of the installation height of the motor fixing plate 21. Motor 23 is a motor that rotates the crankshaft 25. Motor 23 can be, for example, a servo motor, a stepping motor, or the like.

[0017] The crankshaft 25 comprises a rotating shaft 25a and an eccentric shaft 25b. The rotating shaft 25a is a shaft that rotates coaxially with the rotating shaft of the motor 23. The eccentric shaft 25b is a shaft portion that is eccentric to the rotating shaft 25a. In this embodiment, the amount of eccentricity is, for example, 25 mm.

[0018] The movable table 26 is driven by the crank drive unit 20 to reciprocate in the vertical direction Z. As shown in Figure 3(B), the movable table 26 and the table 11 of the base 10 are connected by a shaft 27a and a cylinder 27b. The shaft 27a is located in the central area of ​​the left and right sides of the movable table 26 (see Figure 1(A), etc.). This guides the movable table 26 so that it can move vertically in the Z direction relative to the table 11 of the base 10. Furthermore, the four corners of the movable table 26 are equipped with cylinders 32 to which slide shafts 15 are connected. Details of the cylinders 32 will be described later.

[0019] The arm 28 is a component that connects the shaft portion 26a of the movable table 26 to the eccentric shaft 25b of the crankshaft 25. As shown in Figures 4 and 5, with the above configuration, the crank drive unit 20 rotates the crankshaft 25 by the motor 23, causing the movable table 26 to reciprocate in the vertical Z direction with a stroke (second stroke) corresponding to the eccentricity of the eccentric shaft 25b, which is 25 mm. Consequently, the slide shaft 15 also reciprocates in the vertical Z direction. The stroke of the slide shaft 15 by the crank drive unit 20 (also called the crank stroke) is 50 mm.

[0020] (Air-driven unit 30) As shown in Figures 1 and 3, the air-driven unit 30 is a unit that uses air pressure to move the slide shaft 15 in the vertical direction Z. Four air-driven units 30 are provided near the four corners of the movable table 26. The air-driven unit 30 includes a rod 31 and a cylinder 32. The rod 31 is fixed to the lower part of the slide shaft 15. The cylinder 32 is fixed to the movable table 26. The cylinder 32 houses the rod 31 so that it can move in the vertical direction Z. The cylinder 32 is connected to an air pump (not shown) by an air hose or the like, and the supply and exhaust of air drives the rod 31 in the vertical direction Z.

[0021] As shown in Figures 3 and 4, with the above configuration, the air drive unit 30 moves the slide shaft 15 in the vertical direction Z by driving the slide shaft 15 and the rod 31 together in the vertical direction Z. In this embodiment, the stroke of the slide shaft 15 driven by the air-driven unit 30 (also called the air-driven stroke (first stroke)) is approximately 100 mm.

[0022] (Upper unit 50) As shown in Figures 6 and 7(A), the upper unit 50 comprises an upper plate 51, an upper base portion 52, a pressing portion 55, a spring 56 (elastic support portion), and a support screw 57. The upper plate 51 is a rectangular plate that is elongated in the left-right direction X. The upper part of the slide shaft 15 is screw-fixed to the four corners of the upper plate 51. As a result, the upper plate 51 and the slide shaft 15 are integrally constructed and move together in the vertical direction Z. The upper plate 51 is provided with a support hole 51b and a spring retaining hole 51d. These holes are coaxial.

[0023] The support holes 51b are through holes that penetrate the upper plate 51 vertically in the Z direction for the shaft portion of the support screw 57 to pass through. A total of eight support holes 51b are provided, corresponding to the support screws 57. The spring retaining holes 51d are bottomed holes for holding the spring 56. The spring retaining holes 51d are located on the lower surface of the upper plate 51. A total of eight spring retaining holes 51d are provided, corresponding to the holes of the support holes 51b.

[0024] The upper base portion 52 is a rectangular parallelepiped-shaped plate that is elongated in the left-right direction X. The upper base portion 52 is positioned in the area Z1 below the upper plate 51, with a gap between it and the upper plate 51. The upper base portion 52 is provided with a pilot hole 52b and a spring retaining hole 52d. These pilot hole 52b and spring retaining hole 52d are coaxial with the support hole 51b and spring retaining hole 51d of the upper plate 51. The pilot holes 52b are screw holes for fixing the support screws 57. Eight pilot holes 52b are provided on the upper surface of the upper base portion 52. The spring retaining holes 52d are bottomed holes for holding the spring 56. Four spring retaining holes 52d are provided on the upper surface of the upper base portion 52.

[0025] The pressing portion 55 is a rectangular timber-shaped member. The pressing portion 55 is fixed to the lower surface of the upper base portion 52 by screws or the like. As a result, the pressing portion 55 is fixed so as to protrude downward Z1 from the lower surface of the upper base portion 52. The upper base portion 52 and the pressing portion 55 may be made into a single unit by cutting or processing a metal plate. The lower surface of the pressing portion 55 is the pressing surface 55a that contacts the workpiece W. The pressing surface 55a is a flat surface. The shape of the pressing surface 55a when viewed from the vertical direction Z is rectangular (see Figure 6(A), etc.). The dimensions of the pressing surface 55a in the left-right direction X and the front-back direction Y are, for example, 1000 mm × 20 mm.

[0026] The spring 56 is a biasing member that biases the upper base portion 52 downward Z1. In this embodiment, a compression coil spring is used as the biasing member, but it is not limited to this and other members (for example, a leaf spring) may be used. A total of eight springs 56 are attached to the upper base portion 52. The upper part of the spring 56 is inserted into the spring retaining hole 51d of the upper plate 51, and the lower part of the spring 56 is inserted into the spring retaining hole 52d of the upper base portion 52. In this way, the spring 56 is held in place between the upper plate 51 and the upper base portion 52, preventing it from falling out of the upper plate 51 and the upper base portion 52.

[0027] The support screws 57 are male screws used to support the upper base portion 52 to the upper plate 51, and hexagonal bolts or the like can be used. A total of eight support screws 57 are attached to the upper base portion 52, each inserted through a spring 56. The lower tip Z1 of the support screw 57 is screw-connected to the pilot hole 52b of the upper base portion 52. Furthermore, the shaft portion of the support screw 57 is inserted into the support hole 51b of the upper plate 51, and a nut 57b is attached to the upper part of the support hole 51b. This nut 57b is then secured by a lock nut 57c to prevent it from loosening. The upper base portion 52 can be adjusted in height using support screws 57 and their nuts.

[0028] (Configuration of spring 56) As shown in Figure 6, etc., when viewed from the vertical direction Z (the pressing direction, which is also the direction normal to the pressing surface 55a), the set A56 of spring 56 and its related components (support hole 51b, spring holding hole 51d, pilot hole 52b, spring holding hole 52d, support screw 57, etc.) is arranged in a range of four sets each, totaling eight sets, in the front-rear direction Y (the short side direction of the pressing part 55) outside the pressing surface 55a. The four sets A56 on the front Y1 are arranged on the same line at equal intervals (for example, at intervals of about 80 to 100 mm) along the left-right direction X (the longitudinal direction of the pressing portion 55). Similarly, the four sets A56 on the rear Y2 are arranged on the same line at equal intervals (for example, at intervals of about 80 to 100 mm) along the left-right direction X. In the front-to-back direction Y, the front Y1 set A56 and the rear Y2 set A56 are arranged on the same line. Therefore, the front Y1 set A56 and the rear Y2 set A56 are arranged symmetrically with respect to the pressing surface 55a (with the center line of the pressing surface 55a in between).

[0029] Furthermore, the inner diameter of the support hole 51b in the upper plate 51 is slightly larger (for example, within 1 mm) than the outer diameter of the male screw of the support screw 57. This allows the upper base portion 52 to move vertically in the Z direction in accordance with the expansion and contraction of the spring 56 during the heat sealing process. With the above configuration, the upper base portion 52 is supported by the upper plate 51. When the upper unit 50 is separated from the lower unit 60, the spring 56 is set to its natural length (for example, about 25 mm), but it may also be set to apply preload.

[0030] (Lower unit 60) The lower unit 60 comprises a lower base portion 62, a receiving portion 65, and a conductor 66 (heat-generating portion). The lower base portion 62 and the receiving portion 65 are rigid bodies made of metal or the like. The lower base portion 62 is fixed to the table 11 of the base 10 by screws or the like. The lower base portion 62 is a rectangular parallelepiped member, similar to the upper base portion 52. However, the lower base portion 62 does not have any spring-related components.

[0031] The receiving portion 65 is a rectangular member similar to the pressing portion 55. The receiving portion 65 is fixed to the upper surface of the lower base portion 62 by screws or the like. As a result, the receiving portion 65 is fixed so as to protrude upward Z2 from the upper surface of the lower base portion 62. The receiving portion 65 is a member that receives the pressing portion 55 by sandwiching the workpiece W. The upper surface of the receiving portion 65 is the receiving surface 65a that contacts the workpiece W. The receiving surface 65a is formed as a flat surface.

[0032] As shown in Figure 6(A), etc., when viewed from the vertical Z direction, the pressing surface 55a and the receiving surface 65a are exactly the same size and overlap, but are not limited to this and may be different sizes. Also, the pressing surface 55a and the receiving surface 65a are located on the horizontal plane (XY plane), but are not limited to this and may be inclined with respect to the horizontal plane.

[0033] The conductor 66 is a heating element, that is, an uninsulated wire. The conductor 66 generates heat when a voltage is applied from a power supply (not shown) and a DC or AC current flows through it. In this embodiment, a nichrome wire is used as an example of the conductor 66. The conductor 66 is fixed on an insulating sheet (not shown) placed on the receiving surface 65a. When viewed from above Z2, the conductor 66 is positioned in the center of the receiving surface 65a in the front-to-back direction Y, and parallel to the left-to-right direction X. As a result, the conductor 66 can weld and cut the workpiece W by heating a linear area of ​​the workpiece W along the left-to-right direction X (the longitudinal direction of the pressing part 55). In this embodiment, an impulse heating method (the application period is, for example, 0.3 seconds) is used.

[0034] (The upper unit 50 is driven by the air drive unit 30 and the crank drive unit 20.) The air-driven unit 30 and the crank-driven unit 20 each drive the slide shaft 15 in the vertical direction Z. In Figures 7 to 9, the vertical Z position of the slide shaft 15 is shown by the upper end positions P0 to P3 of the slide shaft 15. Note that the interval between positions P0 to P3 is exaggerated in the illustration and does not represent the actual ratio.

[0035] In the non-operating state and the operating state (top dead center state and bottom dead center state), the air drive unit 30 and the crank drive unit 20 are controlled as follows. As shown in Figure 7(A), the non-operational state is a state in which the sealing device 1 is not heat-sealing the workpiece W, and is a concept that includes, for example, the state in which various settings for heat sealing (such as adjusting the installation height of the upper base portion 52) are being made. As shown in Figures 7(B), 8(A), and 8(B), the operating state of the sealing device 1 is one in which the workpiece W is being continuously heat-sealed. In the top dead center state (see Figure 7(B)) and the bottom dead center state (see Figure 8(B)), the slide shaft 15 is positioned at the upper and lower ends of the total stroke of the crank drive unit 20, respectively.

[0036] As mentioned above, the vertical Z-direction travel stroke of the slide shaft 15 is 100 mm for the air-driven stroke and 50 mm for the crank stroke. Therefore, the total vertical Z-direction stroke of the slide shaft 15 is 150 mm. (Non-operational state) As shown in Figure 7(A), in the non-operating state, the slide shaft 15 is positioned at the upper end P0 of the total stroke of the air drive unit 30 and the crank drive unit 20, which is 150 mm. In other words, the air-driven unit 30 maintains the rod 31 in the uppermost position. As a result, the slide shaft 15 is positioned at the top of the 100mm air-driven stroke (see Figure 3). Meanwhile, the motor 23 of the crank drive unit 20 is controlled so that the eccentric shaft 25b is positioned at the top. As a result, the slide shaft 15 is positioned at the top of the crank stroke of 50 mm. In the non-operating state, the gap L0 between the pressing surface 55a of the pressing part 55 and the receiving surface 65a of the receiving part 65 is 143 mm (total stroke 150 mm - spring compression amount 7 mm), which is sufficiently large. Therefore, the workability of various adjustments is good.

[0037] (Top dead center position) As shown in Figure 7(B), the slide shaft 15 is positioned at a location P1 that is 50 mm lower than the upper end P0. The distance from position P1 to the lower end P3 of the total stroke is 50 mm. In other words, the air-driven unit 30 maintains the rod 31 in its lowest position. As a result, the slide shaft 15 is positioned at the lowest point of the air-driven stroke of 100 mm (see Figure 4). Meanwhile, the motor 23 of the crank drive unit 20 is controlled to keep the eccentric shaft 25b at the top, continuing from the non-operating state. As a result, the slide shaft 15 is positioned at the top of the crank stroke of 50 mm. In the top dead center position, the gap L1 between the pressing surface 55a of the pressing part 55 and the receiving surface 65a of the receiving part 65 is 43 mm (crank stroke 50 mm - spring compression amount 7 mm).

[0038] (Bottom dead center position) As shown in Figure 8(B), the slide shaft 15 is positioned at the lower end P3 of the total stroke, that is, at the lower end P3 which is 150 mm lower than the upper end P0. In other words, the air-driven unit 30 maintains the rod 31 in the lowest position, similar to the top dead center position, and the slide shaft 15 is positioned at the lowest point of the air-driven stroke of 100 mm. On the other hand, the motor 23 of the crank drive unit 20 is controlled to position the eccentric shaft 25b at the lowest point, and the slide shaft 15 is positioned at the lowest point of the crank stroke of 50 mm. In the bottom dead center position, the gap between the pressing portion 55 and the receiving portion 65 is 0 mm, ignoring the thickness of the workpiece W.

[0039] As shown in Figure 9, the motor 23 of the crank drive unit 20 continues to rotate, transitioning from the bottom dead center state (state in Figure 8(B)) to the top dead center state. During this transition, the heat-sealed and cut bag W1 of the workpiece W is fed out, and the next processing portion of the workpiece W is loaded (positioned) into the gap between the pressing portion 55 and the receiving portion 65. The sealing device 1 reciprocates the upper base portion 52 in the vertical direction Z by continuously driving the crank drive unit 20 in this manner. As a result, the sealing device 1 can continuously heat seal the workpiece W. The slide shaft 15 reciprocates in the vertical direction Z with a crank stroke of 50 mm, and consequently the gap between the pressing portion 55 and the receiving portion 65 repeatedly changes between 43 mm (gap L1) and 0 mm.

[0040] (Pressing force on the workpiece W due to the biasing force of spring 56) Figure 8(A) shows the process of transitioning from the top dead center state (see Figure 7(B)) to the bottom dead center state (see Figure 8(B)). As shown in Figure 8(A), before reaching the bottom dead center state, the gap between the pressing part 55 and the receiving part 65 becomes 0 mm, and as a result, the pressing surface 55a of the pressing part 55 begins to press the workpiece W. In this embodiment, the state in which the gap becomes 0 mm is the state in which the slide shaft 15 is positioned at position P2. Then, in the process of transitioning from the state in Figure 8(A) to the bottom dead center state in Figure 8(B), the slide shaft 15 descends a further 7 mm from position P2 to the lower end P3. Therefore, in the bottom dead center position shown in Figure 8(B), the spring 56 is compressed by a total of 7 mm, causing the pressing surface 55a of the pressing part 55 and the receiving surface 65a of the receiving part 65 to press against the workpiece W. In other words, the pressing surface 55a presses against the workpiece W with a pressing force corresponding to the biasing force of the spring 56.

[0041] In one embodiment, for example, the spring constant is 8 kgf / mm and the compressive force is approximately 448 kgf (spring constant 8 kgf / mm × compression amount 7 mm × 8 units). The period for applying an impulse voltage to the conductor 66 can be set as appropriate. For example, it may be limited to the period during which the pressing surface 55a is pressing against the upper surface of the workpiece W, or it may include the period during which the pressing surface 55a is pressing against the upper surface of the workpiece W and the periods before and after this period.

[0042] Figure 10 is a diagram illustrating the positional relationship between the workpiece W, the pressing portion 55, etc., of the embodiment, as viewed from above Z2. Figure 10(A) shows the state in which voltage is applied to the conductor 66, and the sealing area W10a is heat-sealed and cut. Figure 10(B) shows the state in which the manufactured bag W1 is sent out of the processing area, and the workpiece W to be heat-sealed is then sent into the processing area. As shown in Figures 8 and 10(A), during the period when voltage is applied to the conductor 66, the sealing area W10a that overlaps with the conductor 66 within the range of the workpiece W sandwiched between the pressing surface 55a and the receiving surface 65a is heat-sealed and cut, thereby manufacturing the bag W1. As shown in Figures 9 and 10(B), the pressing surface 55a of the pressing part 55 separates from the upper surface of the workpiece W during the transition from the bottom dead center to the top dead center. During this process, the bag W1 is fed out of the processing area, and the workpiece W to be heat-sealed is then fed into the processing area.

[0043] In this embodiment, the above action stabilizes the width of the sealing range W10a and improves the uniformity of the sealing strength. In other words, it reduces variations between bags W1, resulting in a uniform quality. In other words, compared to a conventional configuration in which the upper base portion 52 (pressing portion 55) is not elastically supported, the embodiment provides stable width and seal strength of the seal area W10a between each bag W1 and other bag W1s. Furthermore, even within a single bag W1, the width of the seal area W10a on the front Y1 and the width of the seal area W10a on the rear Y2 become uniform. As a result, sealing defects, such as unsealed portions, are reduced compared to the conventional configuration. The effects of the embodiment described above were confirmed by manufacturing a prototype using a prototype machine.

[0044] The above-mentioned effects and behaviors are thought to be due to the following reasons. The surface of the bubble sheet material W10 is not flat but uneven, and the repulsive force caused by the cap W11a varies depending on the location, so it has characteristics such as not being able to receive the force from the pressing surface 55a uniformly. For this reason, when the pressing surface 55a presses the surface of the two stacked bubble sheet materials W10, slippage occurs at the welded portion between the sheets, and this slippage is considered to be one of the causes of processing defects.

[0045] In this embodiment, when viewed from above Z2, the pressing portion 55 is elastically supported on both the front Y1 and rear Y2 sides, with the pressing surface 55a in between (more specifically, the pressing portion 55 is elastically supported to the upper plate 51 via the upper base portion 52). Therefore, the pressing portion 55 can follow when it tries to tilt unstably in the front-rear direction Y due to the above-mentioned characteristics of the surface of the bubble sheet (see arrow θ52 shown in Figure 8(B)). As a result, the pressing surface 55a can press the surface of the bubble sheet material W10 more firmly than in the conventional method, and can press the surface of the bubble sheet material W10 with a more uniform force. This is considered to enable stable sealing in this embodiment.

[0046] As described above, the sealing device 1 of this embodiment can reduce processing defects when manufacturing a bag W1 by heat sealing the bubble sheet material W10.

[0047] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. Various modifications and changes are possible, such as the modified forms described later, and these are also within the technical scope of the present invention. Furthermore, the effects described in the embodiments are merely a list of the most preferred effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments. Note that the configurations of the embodiments described above and the modified forms described later can be used in part or in combination as appropriate, but a detailed explanation is omitted.

[0048] (Transformed form) (1) In the embodiment, the workpiece is shown as a double-layered (folded in half) bubble sheet material, but is not limited to this. The workpiece may be a bubble sheet material with three or more layers. In addition, the workpiece may be a sheet material other than a bubble sheet material, as long as it can be heat-sealed and cut. Furthermore, the heat sealing device may produce a cylindrical body instead of a bag by simply heat sealing two sheets stacked together, rather than folding them in half.

[0049] (2) In the embodiment, the heat sealing device is shown as having elastic support for the pressing portion, but is not limited to this. The heat sealing device may also have elastic support for the receiving portion to the lower unit. Alternatively, the receiving portion side may be driven up and down instead of the pressing portion side. (3) In the embodiment, an example was shown in which both the pressing surface and the receiving surface are similarly rectangular in shape, but the embodiment is not limited to this. It is sufficient that the area in which the sheet material is sandwiched between the pressing surface and the receiving surface is rectangular in shape. The shape of one of the pressing surface and the receiving surface may be, for example, elliptical.

[0050] (4) In the embodiment, the springs facing each other across the pressing surface are shown to be in the same position in the left-right direction, but the embodiment is not limited to this. The left-right positions of these springs may be different. [Explanation of Symbols]

[0051] 1: Sealing device 15: Slide shaft 20: Crank drive unit 30: Air-driven unit 50: Upper Unit 51b: Support hole 51d: Spring retaining hole 52: Upper base section 52b: Pilot hole 52d: Spring retaining hole 55: Pressing part 55a: Pressing surface 56: Spring 57: Support screw 60: Lower Unit 62: Lower base section 65: Receiving Department 65a: Receiving surface 66: Conductor

Claims

1. A pressing part having a pressing surface that is elongated in the longitudinal direction, A receiving portion having a receiving surface that receives the pressing surface, with the workpiece sandwiched between the pressing surface and the receiving portion, A plurality of elastic support parts that elastically support either the pressing part or the receiving part, The system comprises a heating element that heats and welds the workpiece sandwiched between the pressing element and the receiving element in a linear range along the longitudinal direction, The plurality of elastic support parts are, When the pressing surface is viewed from the normal direction, the following areas are arranged along the longitudinal direction, both in the short direction perpendicular to the longitudinal direction and outside the pressing surface. A heat sealing device characterized by the following features.

2. In addition to welding the workpiece, the aforementioned heating element also melts and cuts it. The heat sealing apparatus according to feature 1.

3. The heating element impulsively heats the workpiece when the workpiece is sandwiched between the pressing element and the receiving element. A heat sealing device according to feature 1 or 2.

4. The workpiece comprises at least two stacked film members, The aforementioned film member is A cap film having multiple caps, The bubble wrap packaging comprises a back film which is laminated onto the cap film to seal air into multiple caps. A heat sealing device according to feature 1 or 2.

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