Cutter

Abstract

To provide a cutter capable of cutting and opening a packing body even when the packing body is placed out of position.SOLUTION: In a cutter that is lowered toward a packing body to push through the packing body, a single-edged back surface in which only one side (back side) of a plate-shaped sub-cutter having a V-shaped blade part in front view is cut at an acute angle is fixed to a single-edged back surface in which only one side (back side) of a plate-shaped main cutter having an inverted V-shaped blade part in front view is cut at an acute angle so that the straight parts of the blades of both cutters cross each other. The cutter includes a bottom cutting part at a horizontal tip part of a lower end of a pair of inverted right triangles in front view which constitute the main cutter.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cutter used to cut and open, for example, a bag-shaped package. [Background technology]

[0002] For example, when powdered or granular industrial raw materials or food ingredients are shipped from a raw material manufacturer, they are packed into large bags and shipped to a processing plant or the like. In the processing plant or the like, the bag-shaped packages are cut and opened, and the contents are temporarily dispensed into a hopper or the like for storage in order to supply the bagged raw materials to a processing device or an automatic bagging device for repacking the bagged raw materials into small bags or the like.

[0003] Patent Document 1, for example, describes a device that cuts the package, opens the bag, and automatically dispenses the contents into a hopper. [Patent Document 1] Patent No. 3987507 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] This application is an improved invention of the cutter according to Patent Document 1. First, the invention according to Patent Document 1 will be outlined with reference to Fig. 4 and Fig. 5. Fig. 4 is a front view of the cutter according to Patent Document 1, and Fig. 5 is a vertical cross-sectional side view taken along line VV in Fig. 4.

[0005] As shown in Figure 4, the bag opening device (1) comprises a pair of left and right base frames (2) facing forward and backward and rising from the floor surface, a pair of front-view gate-type front and rear blade support frames (3) fixed to the upper surfaces of the base frames, and an air cylinder (4) and a pair of left and right guide rods (5) attached to the upper surfaces of the support frames (3).

[0006] The rotating plate (10) places the package (11) to be opened and rotates downward after the bag is opened. As shown in Fig. 5, two rotating plates (10) are provided, one at the front and one at the back, with a gap between the opposing surfaces.

[0007] The cutter (12) is composed of a pair of left and right main cutters (13) that are symmetrical and made of high-speed tool steel plate, for example, 3 mm thick, and a central sub-cutter (14) of the same thickness and material. Both main cutters (13) form a pair of inverted right-angled triangles with their lower ends cut horizontally, and the left and right hypotenuses of the inverted V-shape facing each other have single-edged blade portions (15) cut at an acute angle on only one side (the back side) (see Figure 5).

[0008] To cut and open a package (11), for example a package made of multiple layers of kraft paper containing powder, using the cutter (12) of the above embodiment, as shown in Figure 4, the package (11) having a dimension shorter than the distance between the lower ends of the blade portions (15) of both main cutters (13) is transported by a conveyor or the like to the center of the front and rear rotating plates (10) and placed there, and then the air cylinder (4) is operated to lower the cutter (12) together with the cutter mounting member (9).

[0009] Then, as shown by the dotted line, the blade portions (15) of both main cutters (13) first come into contact with both corners of the upper part of the packaging body (11) and then slide toward the inside and lower part of the packaging body (11), gradually cutting both left and right sides of the packaging body (11) inward.

[0010] Next, the lower end of the sub-cutter (14) penetrates the center of the package (11), and the blade portion (18) slides downward and outward from the package (11), gradually cutting outward from the center. When the intersection of the blade portions (15) and (18) moves to the bottom of the package (11), the center of the package (11) is completely cut (sheared off) and the package is opened.

[0011] In this case, the blades (15) and (18) intersect at an acute angle in an inverted V shape, so the resistance applied to the blades just before the end of cutting is small, and the progress of wear is slowed down, so that the sharpness is maintained. Therefore, no cutting waste is generated, and even if there is an inner bag such as polyethylene inside the package (11), there is no risk of it becoming unable to be cut.

[0012] As described above, the cutter in Patent Document 1 is configured such that the main cutter blade portion (15) and the sub-cutter blade portion (18) form four straight blade portions facing diagonally upward and downward, and the straight blade portions intersect with each other. Therefore, by simply lowering the cutter, bag-shaped packages and the like can be easily and efficiently cut and opened.

[0013] However, the filling rate of the package (11) varies, which can cause the shape of the package (11) to vary. Furthermore, when the package (11) is transported by a conveyor or the like and placed in the center of the rotating plate (10), it may shift from its normal position. Therefore, when the package (11) that is placed in a position that is shifted from the normal position is cut by the cutter (12), the part of the main cutter (13) without the blade portion (15) hits the package (11), which results in the package (11) not being cut and being damaged.

[0014] The present invention has been made in consideration of the above problems, and has an object to provide a cutter that can cut and open a package even if the package is placed in an incorrect position. [Means for solving the problem]

[0015] According to the present invention, the above problems are solved as follows. (1) A cutter that is configured to cut through a packaging body by lowering it toward the packaging body, the cutter comprising a plate-shaped main cutter having an inverted V-shaped blade when viewed from the front, which has a single-edged back surface cut at an acute angle on only one side (the back side) of the main cutter, and a plate-shaped sub-cutter having a V-shaped blade when viewed from the front, which has a single-edged back surface cut at an acute angle on only one side (the back side) of the main cutter, which is fixed so that the straight portions of the blades of both cutters intersect with each other, and which is characterized in that a bottom blade portion is provided at the horizontal tip portion of the lower end of a pair of inverted right-angled triangles when viewed from the front that constitute the main cutter.

[0016] (2) The pair of bottom cutting edges are characterized in that they each have an upward gradient toward the lower end of the inverted V-shaped cutting edge of the main cutter when viewed from the front.

[0017] (3) The angle of the upward gradient of the bottom cutting edge is 1° to 5° with respect to the horizontal direction. Effect of the Invention

[0018] (1) The lower ends of the pair of inverted right-angled triangles in front view that constitute the main cutter are cut horizontally in order to ensure the strength of the cutter tips and for the safety of workers when transporting and replacing the cutter. Until now, no blade was provided on this horizontal tip. Therefore, in order to cut the package and open the bag when it is placed out of place, the blade of the main cutter, which is in the shape of an inverted V shape in front view, must be made longer. However, this approach increases the size of the main cutter, and the entire bag opening device becomes larger. Therefore, according to the first invention, if a bottom blade is provided on the horizontal tip, it is not necessary to change the size of the bag opening device, which is advantageous in terms of cost. In addition, when transporting and replacing the cutter, a blade cover has been attached to the horizontal tip in the past, so that the cost increase factor can also be eliminated in terms of safety.

[0019] (2) According to the first invention, a bottom blade is provided at the horizontal tip of the lower end of a pair of inverted right-angled triangles in front view that constitute the main cutter. Here, when the bottom blade is horizontal, when cutting the package, the bottom blade pushes the package into the cutter to cut it. This push cutting increases the resistance on the bottom blade, which may shorten the grinding and replacement cycle of the bottom blade. According to the second invention, the bottom blade is configured to have an upward slope toward the lower end of the inverted V-shaped blade of the main cutter in front view. This makes it possible to avoid push cutting when cutting the package, and to reduce the resistance on the bottom blade.

[0020] (3) According to the second invention, by providing an upward inclination to the bottom blade portion, it is possible to avoid pushing and cutting when cutting the packaging material. The greater the angle of this upward inclination, the smaller the resistance on the bottom blade portion. On the other hand, if the angle is too large, there is a risk that the strength of the tip of the main cutter cannot be ensured. Therefore, according to the third invention, based on a cutting confirmation test of the packaging material, the angle of the upward inclination of the bottom blade portion is set to 1° to 5° with respect to the horizontal direction, resulting in a more practical shape of the bottom blade portion in terms of maintenance and safety. [Brief description of the drawings]

[0021] [Figure 1] 1 is a front view of a first embodiment of a cutter of the present invention and a bag opening device to which the cutter is applied. [Diagram 2] FIG. 2 is an enlarged front view of the cutter of FIG. [Diagram 3] FIG. 2 is an enlarged front view of a second embodiment of a cutter of the present invention. [Figure 4] FIG. 1 is a front view of a bag opening device to which a conventional cutter is applied. [Diagram 5] FIG. 5 is a vertical sectional side view taken along line VV of FIG. 4. BEST MODE FOR CARRYING OUT THEINVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a front view of a bag opening device (1) to which a first embodiment of a cutter (12) of the present invention is applied. The main cutter (13) is a pair of inverted right triangles that are symmetrical on the left and right, and the tip of each is cut horizontally. This is to ensure the strength of the tip of the inverted right triangle and for the safety of workers when transporting and replacing the cutter. Until now, no blade was provided at this tip.

[0023] The main cutter (13) is made of a high-speed tool steel plate having a thickness of, for example, 3 mm, and has an inverted V-shaped blade portion (15) when viewed from the front, and the blade portion (15) is formed into a single-edged shape by cutting only one side (the back side) at an acute angle. The cutting edge angle of the blade portion (15) formed into a single-edged shape is, for example, 20°.

[0024] The sub-cutter (14) is formed from a high-speed tool steel plate having a thickness of, for example, 3 mm, and has a V-shaped blade portion (18) when viewed from the front, and the blade portion (18) is formed into a single-edged shape by cutting only one side (the rear side) at an acute angle. The cutting edge angle of the blade portion (18) formed into a single-edged shape is, for example, 20°.

[0025] The cutter (12) is a cutter in which the rear surface of the main cutter (13) and the rear surface of the sub-cutter (14) are fixed to each other such that the straight portions of the blade portions of both the inverted V-shaped blade portion (15) when viewed from the front and the V-shaped blade portion (18) when viewed from the front intersect with each other (see FIG. 5 for the above).

[0026] The difference between the cutter (12) of the present invention shown in Fig. 1 and the conventional cutter shown in Fig. 4 is that the main cutter (13) has a bottom cutting edge (35) at the horizontal tip of each of a pair of inverted right triangles. Until now, no cutting edge was provided at these horizontal tips. The reason for providing the bottom cutting edge (35) at the horizontal tip of each of a pair of inverted right triangles will be described later.

[0027] The bottom cutting edge (35) provided at the tip of the main cutter (13) is used integrally with the blade (15) of the main cutter (13), so the bottom cutting edge (35) provided at the tip is also formed into a single-edged shape with only one side (the back side) cut at an acute angle, and the cutting edge angle is set to 20°.

[0028] Fig. 2 is an enlarged front view of the cutter (12) in Fig. 1. The main cutter (13) has a blade portion (15) that is in an inverted V shape when viewed from the front and extends diagonally downward to the lowest portion (point P). A bottom blade portion (35) is formed at the horizontal tip of the main cutter (13). The blade portion (15) and the bottom blade portion (35) are connected at point P.

[0029] The reason why the bottom blade portion (35) is formed on the horizontal tip of the main cutter (13) will be explained with reference to Figs. 1 and 4. The packing material (11) has a variable filling rate, which may cause the shape of the packing material (11) to vary. Furthermore, when the packing material (11) is transported by a conveyor or the like and placed in the center of the rotating plate (10), it may be displaced from its normal position. Therefore, when the packing material (11) placed in a position displaced from its normal position is cut by the conventional cutter (12) shown in Fig. 4, the part of the main cutter (13) without the blade portion (15) hits the packing material (11), causing the packing material (11) to not be cut and to be damaged.

[0030] The present invention has been made to solve the above problems, and as shown in FIG. 1, a bottom cutting edge (35) is formed at the horizontal tip of the main cutter (13), so that the package (11) can be cut and opened even if it is placed out of its normal position.

[0031] When the package (11) is placed out of position, this can be addressed by lengthening the blade (15) of the main cutter (13) which is inverted V-shaped when viewed from the front. However, this solution increases the size of the main cutter (13), which makes the bag opening device (1) larger as a whole. Therefore, if the main cutter (13) is provided with a bottom blade (35) at each of the horizontal tips of the pair of inverted right triangles, it becomes unnecessary to change the size of the bag opening device (1), which is advantageous in terms of the size and cost of the device. In addition, when the main cutter (13) is transported or replaced, a blade cover has been attached to the horizontal tips in the past, so that the cost increase can be eliminated in terms of safety as well.

[0032] 3 is an enlarged front view of a second embodiment of the cutter 12 of the present invention. The bottom blade 35 of the main cutter 13 has an upward slope toward the left and right lower ends (point P) of the blade 15 that is inverted V-shape when viewed from the front.

[0033] In the first embodiment shown in FIG. 2, the bottom blade portion (35) is provided at the horizontal tip of the lower end of a pair of inverted right triangles when viewed from the front, which constitute the main cutter (13). Here, when the bottom blade portion (35) is horizontal, when cutting the packaging body (11), the bottom blade portion (35) presses the packaging body (11) to cut it, which is a push cut. This push cut increases the resistance on the bottom blade portion (35), which may shorten the grinding and replacement cycle of the bottom blade portion (35). According to the second embodiment shown in FIG. 3, the bottom blade portion (35) is configured to have an upward slope toward the left and right lower ends (point P) of the blade portion (15) of the main cutter (13) which is inverted V-shaped when viewed from the front. This makes it possible to avoid push cut when cutting the packaging body (11), and to suppress the resistance on the bottom blade portion (15), thereby preventing the grinding and replacement cycle of the bottom blade portion (15) from being shortened.

[0034] The larger the angle of the upward gradient of the bottom blade portion (11) toward the left and right lower ends (point P) of the blade portion (15) of the main cutter (13), the smaller the resistance applied to the bottom blade portion (35). On the other hand, if the angle is made too large, there is a risk that the strength of the tip portion of the main cutter (13) cannot be ensured. Therefore, based on a cutting confirmation test of the package (11), the angle of the upward gradient of the bottom blade portion (11) is set to 1° to 5° with respect to the horizontal direction. [Industrial Applicability]

[0035] As described above, the improved invention of the present application, which provides a bottom blade portion (35) to the cutter of Patent Document 1, makes it possible to cut and open the package (11) without changing the size of the bag opening device (1) even if the package (11) is placed in an incorrect position. [Explanation of symbols]

[0036] (1) Bag opening device (2) Base frame (3) Blade support frame (4) Air cylinder (5) Guide rod (9) Cutter mounting part (10) Rotating plate (11) Packaging (12) Cutter (13) Main cutter (14) Sub-cutter (15) Blade part (18) Blade part (35) Bottom blade part

Claims

1. A cutter that is configured to cut through a packaging body by lowering it toward the packaging body, comprising a plate-shaped main cutter having an inverted V-shaped blade when viewed from the front, and a plate-shaped sub-cutter having a V-shaped blade when viewed from the front, and a single-edged back surface cut at an acute angle on only one side (the back side) of the main cutter, and a plate-shaped sub-cutter having a V-shaped blade when viewed from the front, and fixed so that the straight portions of the blades of both cutters intersect with each other, the cutter being configured to cut through the packaging body by lowering it toward the packaging body, the cutter comprising a plate-shaped main cutter having an inverted V-shaped blade when viewed from the front, and a single-edged back surface cut at an acute angle on only one side (the back side) of the main cutter, and fixed so that the straight portions of the blades of both cutters intersect with each other, the cutter being configured

2. 2. The cutter according to claim 1, wherein the pair of bottom blade portions each have an upward gradient toward a lower end of the inverted V-shaped blade portion when viewed from the front of the main cutter.

3. 3. The cutter according to claim 2, wherein the angle of the ascending gradient of the bottom cutting edge is 1° to 5° with respect to the horizontal direction.

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