JP2013083595A - Opening strength measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opening strength measuring apparatus capable of stably measuring opening strength of a corrugated box.SOLUTION: The opening strength measuring apparatus for measuring opening strength when opening a corrugated box 1 by ripping off an outer flap 8 from an inner flap 9 of the corrugated box 1 includes: a press plate 3 for pressing one outer flap 8 of a pair of outer flaps 8, 8 of the corrugated box 1; clamp means 25 for depressing the press plate 3 in contact with the outer flap 8 downward to increase contact pressure between the press plate 3 and the outer flap 8; a hook 5 to be hooked on the other outer flap 8 of the pair of outer flaps 8, 8; and an up/down driving device 6 for pulling up a load measuring unit 4 connected to the hook 5.

Description

  The present invention relates to an opening strength measuring apparatus for measuring an opening strength of a cardboard box.

  Canned beverages, plastic bottle beverages, and the like are transported in a cardboard box from the time the factory is shipped until they are displayed at retail stores or loaded into vending machines. And, as a corrugated cardboard box for canned beverages, plastic bottle beverages, etc., a pair of outer flaps bonded to a pair of inner flaps with a hot melt adhesive, and a lid or bottom formed with the outer flaps and inner flaps is generally used Is done.

  The opening strength of such a cardboard box has a problem whether it is too small or too large, and it is necessary to manage it so as to fall within a predetermined range. In other words, if the opening strength is too low when the outer flap is peeled off from the inner flap, the cardboard box lid may be opened during transportation of the cardboard box, or the bottom of the cardboard box may come off due to the weight of the contents. There is. On the other hand, if the opening strength is too high, a large force is required when opening the cardboard box at a retail store or the like, and there is a problem that the opening workability of the cardboard box is lowered. Further, a large force is required when dismantling the empty cardboard box, and the dismantling workability of the cardboard box is also deteriorated. Therefore, it is necessary to manage the opening strength of the cardboard box so that it falls within a predetermined range.

  And in order to manage the opening strength of the cardboard box, in the boxing line of the factory, the outer flap is adhered to the inner flap with a hot melt adhesive, and the corrugated cardboard box in a state where sealing is completed is periodically sampled. The opening strength of the corrugated cardboard box extracted in the above is measured, and as a measuring method, conventionally, a method of measuring the opening strength of the cardboard box by the operator's hand has been adopted.

  Specifically, first, the cardboard box is placed with the outer flap and the inner flap side facing up, and then one of the opposing outer flaps is pressed by the operator with the hand, Corrugated cardboard by hooking the hook to the outer flap and pulling off the outer flap by the operator pulling the portable load measuring instrument connected to the hook by hand, and measuring the required lifting force with the load measuring instrument. The opening strength of the box was measured.

  However, in such a manual measurement, there are individual differences in the pulling speed and pulling direction of the outer flap, so when different workers measure the opening strength of cardboard boxes, the measured values vary. There was a problem that occurred.

  Therefore, in order to reduce the variation in the measured values, the inventors of the present invention have devised an opening strength measuring device capable of peeling the outer flap at a constant pulling speed and pulling direction. This unsealing strength measuring device is configured to mount a cardboard box with an outer flap and an inner flap facing upward, and one outer pair of outer flaps of the cardboard box placed on the mounting table. It consists of a pressing plate that holds the flap, a hook that is hooked to the other outer flap, and an elevating drive device that lifts the load measuring instrument connected to the hook upward.

  When measuring the unsealing strength with this unsealing strength measuring device, the cardboard box is placed on the mounting table with the side with the outer flap and the inner flap facing upward, and one of the pair of opposing outer flaps of the cardboard box is placed outside. The pressing plate is brought into contact with the flap to fix the position of the pressing plate, the hook is hooked to the other outer flap, and the load measuring device connected to the hook is pulled up by the lifting drive device, and the outer flap is peeled off. Measure the lifting force with a load measuring device.

  However, when actually measuring the opening strength with this opening strength measuring device, although the variation in measured values was smaller than the conventional measurement method of pulling up the load measuring instrument by the hand of the operator, the measured value of the opening strength is still It turns out to be unstable. If it is possible to stably measure the opening strength of a cardboard box, it becomes possible to accurately manage the opening strength based on the same standard even in a plurality of factories.

  In addition, the thing of patent document 1 is proposed as an opening strength measuring apparatus aiming at reducing the dispersion | variation in the measured value of opening strength. The unsealing strength measuring device described in Patent Document 1 includes a hook connected to a load measuring device, a cart provided movably in a horizontal direction, left and right guide walls for guiding the movement of the cart, and a hook. And a feed screw mechanism for relatively moving the carriage. When measuring the unsealing strength with this unsealing strength measuring device, place the cardboard box sideways on the cart, hook the hook on the outer flap of the cardboard box on the cart, and move the cart relative to the hook Then, the outer flap is peeled off, and the lifting force required at this time is measured with a load measuring instrument connected to the hook.

  However, with the opening strength measuring device described in Patent Document 1, there is a possibility that the opening strength when the cardboard box is actually opened at a retail store or the like cannot be accurately managed. That is, the unsealing strength measuring device of Patent Document 1 measures the unsealing strength with the side with the outer flap and the inner flap facing sideways, whereas when actually opening the cardboard box at a retail store or the like, Often, cardboard boxes are opened with the outer and inner flaps facing up. Therefore, the unsealing strength measured by the unsealing strength measuring device of Patent Document 1 cannot be said to faithfully reproduce the unsealing strength when the corrugated box is actually opened at a retail store or the like. For accurate management, it is preferable to measure the opening strength with the outer flap and the inner flap side facing upward.

JP 2006-337101 A

  The problem to be solved by the present invention is to provide an opening strength measuring device capable of stably measuring the opening strength of a cardboard box.

  As a result of changing the measurement conditions and repeating the measurement test of the opening strength, when the pressing plate is brought into contact with one of the opposing outer flaps, a preload is applied between the pressing plate and the outer flap. When not hooked, a slight play remains between the holding plate and the outer flap due to the flexibility of the cardboard, so that when the hook hooked on the other outer flap is pulled up, the position of the cardboard box becomes unstable and becomes minute. It was found that a movement occurred and that the movement affected the measurement of opening strength. The inventors of the present invention apply a preload between the pressing plate and the outer flap when the pressing plate is brought into contact with one outer flap of the pair of opposed outer flaps, thereby allowing the other outer flap to contact the outer flap. It was found that the measured value was stable when the opening strength was measured by pulling the hook hooked on the flap.

  Based on this knowledge, the present invention measures the opening strength when a pair of outer flaps are bonded to a pair of inner flaps and the outer flap of the cardboard box whose opening is sealed is peeled off from the inner flap and opened. One of the pair of outer flaps of the cardboard box mounted on the mounting table for mounting the cardboard box with the outer flap and the inner flap side facing upward, A pressing plate for pressing the outer flap, a clamping means for increasing the contact pressure between the pressing plate and the outer flap by pushing down the pressing plate in contact with the outer flap, and the other of the pair of outer flaps A configuration including a hook that is hooked to the outer flap of the sash and a lifting drive device that lifts the load measuring instrument connected to the hook upward is employed.

  In this way, the cardboard box is placed on the mounting table with the side with the outer flap and the inner flap facing upward, and the pressing plate is brought into contact with one outer flap of the pair of outer flaps of the cardboard box. A preload can be applied between the pressing plate and the outer flap by pushing the plate downward by the clamping means to increase the contact pressure between the pressing plate and the outer flap. Therefore, it is possible to prevent the posture of the cardboard box from becoming unstable when the hook hooked on the other outer flap is pulled up, and to stably measure the opening strength of the cardboard box with a load measuring device connected to the hook. It becomes possible.

  The pressing plate can be supported so that the movement between the position contacting the outer flap and the position retracting from the contact position is a horizontal movement or a swinging movement. It is preferable to provide a lock means that supports the movement between the position in contact with the position and the position retracted from the contact position to be a parallel movement in the vertical direction and can fix the pressing plate at an arbitrary height position. . If it does in this way, since a press board can be fixed in the position according to the height of the cardboard box, it becomes possible to measure the opening strength of a plurality of kinds of cardboard boxes with one opening strength measuring device.

  As the clamping means, for example, a plurality of different distances from the rotation center are supported so as to be able to rotate while being in contact with the upper surface of the pressing plate, and the distance from the rotation center to the outer periphery changes according to the rotation angle. It is possible to employ one having an eccentric cam provided with a flat clamp surface on the outer periphery and an operation lever capable of switching the clamp surface contacting the upper surface of the pressing plate by rotating the eccentric cam. By doing this, the pressing down amount of the pressing plate by the eccentric cam is changed by switching which clamping surface is in contact with the upper surface of the pressing plate among the multiple clamping surfaces with different distances from the rotation center. It is possible to adjust the contact pressure between the pressing plate and the outer flap.

  When the hook is connected to a load measuring instrument so as to be swingable back and forth, an operation of hooking the hook on the outer flap becomes easy. In this case, the hook can be connected to the load measuring instrument so as to be able to swing left and right. However, in this case, of the pair of inner flaps adhered to the outer flap, the one having weak adhesion to the outer flap. There is a possibility that the tensile load concentrates on the inner flap and the proper opening strength cannot be measured. Therefore, it is preferable that the hook is connected to a load measuring device so as not to swing from side to side. If it does in this way, since a tensile load acts on each inner flap equally, it becomes possible to measure appropriate opening strength.

  When the unsealing strength measuring device of the present invention is used, a pressing plate is brought into contact with one outer flap of a pair of outer flaps of the cardboard box, and the pressing plate is pushed downward by a clamping means to be interposed between the pressing plate and the outer flap. By increasing the contact pressure, a preload can be applied between the pressing plate and the outer flap. Therefore, it is possible to prevent the posture of the cardboard box from becoming unstable when the hook hooked on the other outer flap is pulled up, and the opening strength of the cardboard box can be stably measured. As a result, even in a plurality of factories, it is possible to accurately manage the opening strength based on the same standard.

The right view which shows the opening strength measuring apparatus of embodiment of this invention Front view of the opening strength measuring apparatus shown in FIG. Rear view of the opening strength measuring device shown in FIG. Sectional view along line IV-IV in FIG. Sectional view along line VV in FIG. Sectional view along line VI-VI in FIG. Sectional view along line VII-VII in FIG. Sectional view along line VIII-VIII in FIG. The side view which expands and shows the eccentric cam of FIG. The figure which shows the state which rotated the eccentric cam shown in FIG. 9, and switched the clamp surface which contacts the upper surface of a pressing plate. The figure which shows the state which further rotated the eccentric cam shown in FIG. 9, and switched the clamp surface which contacts the upper surface of a pressing plate. The figure which shows the state which further rotated the eccentric cam shown in FIG. 9, and switched the clamp surface which contacts the upper surface of a pressing plate. Enlarged view of the vicinity of the hook shown in FIG. FIG. 13 is an enlarged view of the vicinity of the joint member. Sectional view along line XV-XV in FIG. The figure which shows the state which pulled up the load measuring instrument shown in FIG. 4 with the raising / lowering drive apparatus, and peeled off the outer flap. 1 is a perspective view of the cardboard box shown in FIG.

  1 to 3 show an unsealing strength measuring device according to an embodiment of the present invention. This unsealing strength measuring device includes a mounting table 2 on which a cardboard box 1 is placed in a state in which a product such as a can beverage or a plastic bottle beverage is contained, a pressing plate 3 that holds the cardboard box 1 on the mounting table 2, and a load. It has a hook 5 suspended from the measuring instrument 4 and an elevating drive device 6 for lifting the load measuring instrument 4 upward.

  Here, as shown in FIG. 17, the cardboard box 1 for measuring the opening strength includes a pair of opposed outer flaps 8, 8 and a pair of opposed inner flaps 9, 9 connected to one end of the cylindrical wall 7. And a pair of outer flaps 8 and 8 are bonded to the pair of inner flaps 9 and 9 with a hot melt adhesive 10 to seal the opening. Then, the cardboard box 1 is placed with the outer flap 8 and the inner flap 9 facing upward, and the force required to pull the outer flap 8 upward and peel it from the inner flap 9 is measured as the opening strength. To do.

  As shown in FIGS. 1 to 3, the mounting table 2 has a horizontal mounting surface 11 on which the cardboard box 1 is mounted. A pair of left and right vertical frames 12, 12 extending upward from the mounting surface 11 are fixed to the mounting table 2, and the upper ends of the vertical frames 12 are connected by a horizontal frame 13. On the front surface of each vertical frame 12, a guide rail 14 that extends in the vertical direction and a slider 15 that is slidably held along the guide rail 14 are provided.

  As shown in FIG. 4, a bracket 16 for supporting the pressing plate 3 is attached to the slider 15 so that the slider 15 and the pressing plate 3 move up and down together. The length of the guide rail 14 that guides the slider 15 is set such that it can move further upward from the state in which the pressing plate 3 is in contact with the outer flap 8. Here, the pressing plate 3 is supported so that the movement between the position in contact with the outer flap 8 and the position retracted upward from the contact position is a vertical translation.

  A lock member 17 capable of fixing the slider 15 at an arbitrary slide position with the guide rail 14 interposed therebetween is attached to the bracket 16 that supports the press plate 3, and the press plate 3 is fixed by fixing the slider 15 with the lock member 17. Can be fixed at any height position. As shown in FIG. 7, the lock member 17 is formed in a cross-sectional C shape in which the front ends of opposing pieces facing left and right with the guide rail 14 interposed therebetween, and generates a braking force by sandwiching the guide rail 14. The locked state and the unlocked state in which the holding of the guide rail 14 is released can be switched by lever operation.

  As shown in FIG. 4, the bracket 16 includes a back plate 18 fixed to the left and right sliders 15 and a front extension plate 19 extending forward from the back plate 18. The pressing plate 3 is disposed to face the front extending plate 19 and the pressing plate 3 through a reamer bolt 20.

  As shown in FIG. 8, the reamer bolt 20 includes a screw shaft portion 21 screwed and fixed to the holding plate 3 and a cylindrical portion 23 slidably fitted into a vertical through hole 22 formed in the front extension plate 19. And a flange portion 24 provided at the upper end of the cylindrical portion 23, and the relative movement of the pressing plate 3 with respect to the front extending plate 19 is allowed by sliding the cylindrical portion 23 with respect to the through hole 22, while the front extending plate The movement range of the presser plate 3 is regulated by the flange portion 24 coming into contact with the upper surface of 19.

  As shown in FIGS. 7 and 8, the front extension plate 19 increases the contact pressure between the presser plate 3 and the outer flap 8 by pressing down the presser plate 3 in a state of contacting the outer flap 8 with its own weight. A clamping means 25 is provided. The clamp means 25 includes a rotation operation shaft 26 extending in the left-right direction, an eccentric cam 27 fixed to the rotation operation shaft 26, and an operation lever 28 provided at one end of the rotation operation shaft 26.

  As shown in FIGS. 9 to 12, on the outer periphery of the eccentric cam 27, there are a plurality of flat clamp surfaces 29 having different distances from the rotation center so that the distance from the rotation center to the outer periphery changes according to the rotation angle. Is provided. The eccentric cam 27 is rotatably supported in a state of protruding to the lower side of the front extension plate 19, and a portion protruding to the lower side of the front extension plate 19 is in contact with the upper surface of the holding plate 3. It is possible to change the relative distance between the front extension plate 19 and the pressing plate 3 by switching the clamp surface 29 contacting the upper surface of the pressing plate 3 by rotating the operation lever 28 while maintaining the contact state. Yes. Here, the amount of change in the relative distance between the front extension plate 19 and the pressing plate 3 due to the rotation operation of the eccentric cam 27 is set in the range of 1.0 to 3.0 mm.

  As shown in FIG. 7, the eccentric cams 27 are provided in pairs on the left and right sides so as to push down the pressing plate 3 evenly on the left and right. The pressing plate 3 is formed wider than the outer flap 8 so as to uniformly press the outer flap 8 of the cardboard box 1 over the entire width. Further, the presser plate 3 is formed of a transparent material (for example, a transparent acrylic resin) in order to improve the visibility of the upper surface of the cardboard box 1.

  As shown in FIGS. 1 to 3, a balance weight 31 is connected to the bracket 16 that supports the pressing plate 3 via a wire 30. The wire 30 is wound around a pulley 32 that is rotatably provided at the upper end of the vertical frame 12. By balancing the weight of the bracket 16 and the balance weight 31 via the wire 30, the wire 30 can be used with an extremely light force. The raising and lowering operation of the pressing plate 3 is enabled.

  Here, since the balance weight 31 in the suspended state is unstable, in order to prevent the balance weight 31 from swinging when the balance weight 31 is raised and lowered, as shown in FIG. The balance weight 31 is guided to be moved up and down by two guide rods 34 slidably passing through the through hole 33.

  As shown in FIG. 3, a square pipe 35 is fixed to the horizontal frame 13 so as to extend upward from the center of the horizontal frame 13. As shown in FIG. 4, a guide rail 36 extending in the vertical direction and a slider 37 slidably held along the guide rail 36 are provided on the front surface of the square pipe 35.

  A bracket 38 that supports the elevating drive device 6 is attached to the slider 37, and the slider 37 and the elevating drive device 6 are moved up and down together in parallel. As shown in FIG. 6, the bracket 38 is formed in an L-shaped cross section along the outer periphery of the square pipe 35, and an index plunger 39 is attached to a portion facing the side surface of the square pipe 35.

  As shown in FIGS. 4 and 6, the index plunger 39 has a stopper pin 40 biased by a spring (not shown) toward the side surface of the square pipe 35. A plurality of stopper holes 41 are provided at intervals in the vertical direction, and when the position of the stopper pin 40 coincides with the stopper hole 41, the tip of the stopper pin 40 enters the stopper hole 41 and the lifting drive device 6 The height of the is fixed.

  Here, the positions of the stopper holes 41 are arranged at positions corresponding to a plurality of types of cardboard boxes 1 having different heights, and the height of the lifting drive device 6 is set to the height of each type of cardboard box 1. It can be changed to the optimal position based on it. The index plunger 39 is provided with a knob 42 for performing an operation of pulling out the stopper pin 40 from the stopper hole 41.

  As shown in FIG. 5, the lifting drive device 6 includes an electric motor 43, a screw shaft 44 to which rotation of the electric motor 43 is input, a linear shaft 45 arranged in parallel to the screw shaft 44, and a screw shaft 44. An elevating block 48 provided with a screw hole 46 that engages with a screw and a guide hole 47 that is slidably fitted to the linear shaft 45, and converts the rotation of the electric motor 43 into the elevating operation of the elevating block 48. Output. As shown in FIG. 4, the electric motor 43, the screw shaft 44, and the linear shaft 45 are assembled and integrated with a base plate 49, and the base plate 49 is fixed to the bracket 38. Further, a cover 50 that covers the elevating drive device 6 is attached to the base plate 49.

  As shown in FIGS. 4 and 6, the load measuring device 4 is connected to the elevating block 48 through a linear guide 51 so as to be movable up and down. Further, an adjustment bolt 52 for relative positioning of the load measuring device 4 and the lifting block 48 is provided between the lifting block 48 and the load measuring device 4, and a load applied to the lifting block 48 by the rotation operation of the adjusting bolt 52. The mounting height of the measuring device 4 can be adjusted.

  As shown in FIG. 4, the load measuring instrument 4 has a measurement shaft 53 protruding downward, and the tensile force applied to the measurement shaft 53 is measured and displayed on the display window 54 (see FIG. 2). A hook 5 is connected to the measuring shaft 53 of the load measuring device 4 via a joint member 55.

  As shown in FIGS. 13 to 15, the joint member 55 includes a bifurcated arm 56 whose upper end is fixed to the measurement shaft 53 and whose lower end is divided into left and right bifurcated portions, and a swing shaft 57 provided at the bifurcated portion of the bifurcated arm 56. And a swing arm 58 connected to the bifurcated arm 56 via the swing shaft 57 so as to swing back and forth. The swing arm 58 and the hook 5 are connected to each other by an elongated hole 59 formed in the hook 5 and a screw 60 so that the position can be adjusted in the vertical direction. Here, the degree of freedom of the joint member 55 is only the back-and-forth swing around the swing shaft 57 extending in the left-right direction, and the hook 5 and the measurement shaft 53 are connected so as not to swing left and right. ing.

  As shown in FIGS. 8 and 13, the hook 5 includes a vertical plate portion 61 that extends downward from the joint member 55, a horizontal plate portion 62 that is disposed below the vertical plate portion 61, and a lower end of the vertical plate portion 61. It consists of a connecting plate portion 63 that connects the rear end of the horizontal plate portion 62, and is used by hooking the horizontal plate portion 62 on the outer flap 8 by swinging back and forth.

  An example of using this unsealing strength measuring device will be described below. First, the cardboard box 1 in a state in which the outer flap 8 is bonded to the inner flap 9 with the hot melt adhesive 10 and the sealing is completed in a state in which products such as canned beverages and plastic bottle beverages are accommodated, The cardboard box 1 is mounted on the mounting table 2 with the side with the flap 9 facing upward. Next, the hook 5 is hooked on one outer flap 8, the pressing plate 3 is brought into contact with the upper surface of the other outer flap 8 by its own weight, and the lock member 17 is operated in this state to fix the position of the pressing plate 3. . At this time, as shown in FIG. 12, the rotation angle of the eccentric cam 27 is set in advance with the operation lever 28 so that the relative distance between the front extension plate 19 and the pressing plate 3 is minimized.

  Then, after fixing the position of the pressing plate 3 in contact with the upper surface of the outer flap 8, as shown in FIG. 9, the eccentric cam 27 is rotated by the operation of the operating lever 28, and the front extension plate 19 and the pressing plate are moved. 3 is increased, the presser plate 3 is pushed downward by increasing the relative distance, and the contact pressure between the presser plate 3 and the outer flap 8 is increased. After that, as shown in FIG. 16, the outer flap 8 is peeled off by pulling up the load measuring device 4 connected to the hook 5 by the lifting drive device 6, and the lifting force required at this time is measured by the load measuring device 4, The measured value at the moment when the pulling force becomes maximum is output as the opening strength.

  In the above opening strength measuring device, the load measuring device 4 is pulled up by the lifting / lowering driving device 6 that outputs the driving force of the electric motor 43 converted into the lifting / lowering operation, and therefore the outer flap 8 is peeled off at a constant pulling speed and pulling direction. Therefore, it is possible to reduce variation in measured values as compared with the conventional measurement method in which the load measuring instrument 4 is pulled up by the operator's hand.

  Further, in the conventional method in which one outer flap 8 is pressed by the operator's hand, when the other outer flap 8 is peeled off, there is a possibility that the measurement value may vary due to individual differences in how the outer flap 8 is pressed. However, in the above-described opening strength measuring device, the pressing plate 3 in contact with the outer flap 8 is further pushed down by a predetermined distance to press the outer flap 8, so that individual differences occur in the pressing method of the outer flap 8. Therefore, the measured values are less likely to vary.

  Here, if the opening strength is measured in a state where the preload is not applied by the clamping means 25 between the outer flap 8 and the pressing plate 3, the gap between the pressing plate 3 and the outer flap 8 due to the flexibility of the cardboard. Since play remains, when the outer flap 8 is peeled off by pulling up the load measuring device 4 connected to the hook 5 by the lifting drive device 6, the posture of the cardboard box 1 becomes unstable and minute movement occurs. The movement may affect the measurement value of the opening strength, and the measurement value of the opening strength may become unstable.

  On the other hand, the unsealing strength measuring device of the above embodiment can press down the holding plate 3 with the clamping means 25 and apply a preload between the holding plate 3 and the outer flap 8, so that the load measurement connected to the hook 5 is measured. When the outer flap 8 is peeled off by pulling up the container 4 with the lifting / lowering drive device 6, the posture of the cardboard box 1 can be prevented from becoming unstable, and the opening strength of the cardboard box 1 is stably measured. be able to. Therefore, when the opening strength measuring device is used, it is possible to accurately manage the opening strength on the same basis even in a plurality of factories.

  Further, in the unsealing strength measuring device of the above embodiment, the pressing plate 3 is supported so as to move in parallel up and down, and the pressing plate 3 can be fixed at an arbitrary height position by the lock member 17. The presser plate 3 can be fixed at a position corresponding to the height of the cardboard, and the opening strength of a plurality of types of cardboard boxes 1 can be measured with a single opening strength measuring device.

  Moreover, since the opening strength measuring apparatus of the said embodiment uses the eccentric cam 27 which has the some clamp surface 29 as the clamp means 25, any clamp surface 29 from which the distance from a rotation center differs is clamped. By switching with the operation lever 28 whether the surface 29 is in contact with the upper surface of the pressing plate 3, the pressing amount of the pressing plate 3 by the eccentric cam 27 can be changed, and the contact pressure between the pressing plate 3 and the outer flap 8. Can be adjusted.

  The hook 5 to be hooked on the outer flap 8 can be connected to the load measuring instrument 4 so as to be swingable right and left, but in this way, of the pair of inner flaps 9 and 9 bonded to the outer flap 8, There is a possibility that the tensile load concentrates on the inner flap 9 that is weakly bonded to the outer flap 8, and the proper opening strength cannot be measured. On the other hand, in the opening strength measuring device of the above embodiment, the hook 5 is connected to the load measuring device 4 so as not to swing from side to side. It is possible to measure the unsealing strength.

  When the load measuring device 4 connected to the hook 5 is pulled up by the lifting / lowering driving device 6, the lifting speed of the load measuring device 4 is preferably set in the range of 100 to 600 mm / min. By setting it to 600 mm / min or less, the measured value of the load measuring device 4 can be stabilized. Moreover, by setting to 100 mm / min or more, the time required for measurement of the opening strength can be suppressed, and the working efficiency can be improved.

  Then, the lifting speed of the load measuring device 4 may be held at a constant value within the predetermined range from the start of lifting to the end of lifting, but the lifting speed is gradually increased from the start of lifting, It is preferable to control the speed of the electric motor 43 of the elevating drive device 6 so as to reach the constant value when 100 msec to 300 msec have elapsed. If it does in this way, the pulling-up speed of the load measuring device 4 becomes close to the pulling speed at the time of actual opening by a human hand, and it becomes possible to obtain a measured value close to the actual opening strength.

DESCRIPTION OF SYMBOLS 1 Corrugated-cardboard box 2 Mounting stand 3 Holding plate 4 Load measuring instrument 5 Hook 6 Lifting drive device 8 Outer flap 9 Inner flap 17 Lock member 25 Clamp means 27 Eccentric cam 28 Operation lever 29 Clamp surface

Claims (4)

A pair of outer flaps (8, 8) are bonded to a pair of inner flaps (9, 9), and the outer flap (8) of the cardboard box (1) sealed with an opening is peeled off from the inner flap (9). In the unsealing strength measuring device that measures the unsealing strength when unsealing,
A mounting table (2) for mounting the cardboard box (1) with the side having the outer flap (8) and the inner flap (9) facing upward, and a cardboard box (1) mounted on the mounting table (2) ) Of the pair of outer flaps (8, 8), and a pressing plate (3) that presses one outer flap (8) and the pressing plate (3) in contact with the outer flap (8) downward Clamp means (25) for increasing the contact pressure between the pressing plate (3) and the outer flap (8) by pushing down, and hooking on the other outer flap (8) of the pair of outer flaps (8, 8) An opening strength measuring device comprising a hook (5) and an elevating drive device (6) for pulling up a load measuring device (4) connected to the hook (5).   The pressing plate (3) is supported so as to translate vertically between a position in contact with the outer flap (8) and a position retracted from the contact position. The unsealing strength measuring device according to claim 1, further comprising lock means (17) that can be fixed at a height position.   The clamp means (25) is rotatably supported in contact with the upper surface of the pressing plate (3), and has a distance from the rotation center such that the distance from the rotation center to the outer periphery changes according to the rotation angle. An eccentric cam (27) provided with a plurality of different flat clamp surfaces (29) on the outer periphery, and a clamp surface (29) contacting the upper surface of the pressing plate (3) by rotating the eccentric cam (27). The opening strength measuring device according to claim 1 or 2, further comprising a switchable operation lever (28).   The hook (5) is connected to the load measuring device (4) so that the hook (5) can swing back and forth and does not swing left and right, and the hook (5) is removed by swinging back and forth of the hook (5). The opening strength measuring device according to any one of claims 1 to 3, wherein the device is hooked on the flap (8).

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