JP4757415B2 - Cap tightening method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, a cap having a screw portion that is screwed into a screw portion formed in a container mouth portion is disposed in a capper having a servo motor capable of detecting and controlling a torque value, and the cap is provided in the container mouth portion. The present invention relates to a cap winding method for covering and tightening.
[0002]
[Prior art]
Conventionally, a method described in Japanese Patent Publication No. 6-76107 has been known as a method for controlling a closing torque when a cap is screwed onto a container.
In the method described in the above publication, when the cap is tightened on the container and the rotation of the capping head is reduced in a capper using a torque motor, the deceleration of the capping head becomes a predetermined value. The inertia torque of the capping head is maintained substantially constant by controlling the command torque, and the cap is tightened to the container with a command torque having a magnitude obtained by subtracting the inertia torque of the capping head from the predetermined closing torque. Is to be terminated.
[0003]
Further, in the cap winding, a plurality of stages with different appropriate torque values, that is, a screw search until the screw part of the cap is put on the container mouth part and screwed into the male screw, and the screw of the cap is the container mouth There are provisional tightening that is smoothly screwed and fitted along the male screw of the part, and final final tightening, and it is desirable to change the winding condition for each of these sub-processes.
FIG. 3 is a diagram for explaining a case where a cap provided with a servo motor or the like is used, and the winding process is divided into a plurality of sub-processes, and for example, a resin cap for beverage is wound around the container mouth, FIG. 4 is a graph showing the variation of the torque value in the winding process shown in FIG. In this method, the cap is wound using a specified rotational speed in accordance with the conventional technique. That is, when the screw search step Arpm, the preliminary winding step Brpm, and the final tightening step Crpm are individually set and the monitored speed decreases from the set value, it is estimated that the upper end of the container is in contact with the packing surface inside the resin cap. Then, the winding process is switched or the end of the winding process is recognized. For example, as shown in FIG. 3, when the rotation speed monitoring value reaches a preset rotation speed P, the temporary winding process is switched to the final tightening process.
[0004]
Conventionally, the end of winding of the cap around the container by the servo motor or the like and the non-defective product determination are controlled by ending the torque transmission by operating the clutch or stopping the servo motor when the set torque is reached. The end of tightening and the non-defective product judgment were performed.
[0005]
[Problems to be solved by the invention]
However, in the conventional control method described above, it has been impossible to detect whether or not the upper end of the container mouth portion has reliably contacted the cap top surface packing portion. In addition, in the conventional control method, since the angle at which the cap is tightened to the container mouth cannot be detected, in order to measure the tightening angle, the tightening angle is measured after opening the cap of the container after tightening, It was judged good / bad.
[0006]
The problems with such prior art are as follows:
1. When the thread shape defect originates from the container or cap, the tightening torque increases, the specified top surface packing part cannot be contacted, and the sealing performance may not be ensured.
2. If the container and cap thread are damaged during tightening, the tightening torque will increase, and the specified top surface packing may not be able to be contacted, and sealing may not be secured.
3. When a cap top surface packing part defective molded product or the like is tightened, the tightening torque increases, and the specified top surface packing part cannot be contacted, and sealing performance may not be ensured.
4). If the cap is obliquely covered during tightening, the tightening torque will increase, and it may not be possible to make contact with the specified top surface packing portion, and the sealing performance may not be ensured.
5. When tightening, when an inner plug such as a one-piece cap is poorly inserted or when an outer seal is bitten, the tightening torque increases, and the specified top surface packing portion cannot be contacted, and sealing performance may not be ensured.
6). When a slip occurs between the winding chuck and the cap, the winding process ends without reaching the necessary torque.
7). When slipping occurs between the container and the container fixing portion during winding, the winding process ends without reaching the necessary torque.
8). When different types of caps with different filling and sterilization conditions are mixed, the sealing is not ensured because the winding is performed under the different conditions.
[0007]
When the above problems occur, the conventional method cannot detect defects during winding, and it is difficult to determine the appearance visually.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cap tightening method that can reliably identify defective cap tightening products and distinguish them from non-defective products.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention uses a cap provided with a servo motor capable of detecting and controlling a torque value of a cap having a screw portion that is screwed into a screw portion formed in a container mouth portion. In the cap tightening method that covers and tightens the container mouth, the tightening process is divided into at least sub-processes before final tightening and final tightening, and the torque monitoring value gradually increases until the end point is reached. increased sharply when the seaming takes power, the time of reaching the temporary tightening set torque, which is a peak lower than the final fastening set torque as a temporary seaming end point, the main tightening preceding substep at this point It is shifted to the tightening sub-step, and the fastening end point when the tightening completion stops the servo motor has been confirmed monitored value reaches the present tightening the set torque, the tightening of the temporary seaming end point It detects the cap rotation angle between the end point, and detects the integration time to the fastening ends of the temporary seaming completion, monitoring torque for the tightening set torque, the cap rotation angle and the integration time is set in advance providing cap tightening method for determining the good or defective for seaming on whether within the scope.
[0009]
In the cap tightening method of the present invention, it is desirable to further include a criterion for determining whether or not the accumulated time from the end of the temporary tightening to the end of the final tightening is within the range of the preset accumulated time.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an outline of a capper used in an embodiment of a cap winding method according to the present invention.
The capper mainly includes a servo motor 1, a cap grip 4 provided at the tip of the spindle of the servo motor 1, and a control unit 5 such as a servo amplifier for controlling the servo motor 1. ing. In this capper, the cap 2 held by the cap gripping portion 4 is put on the mouth portion of the container 3, and is screwed and fitted in the closing direction so as to be tightened to seal the container mouth portion. Yes. Although the details of the capper are not shown, container holding means are provided at equal intervals on the outer periphery of the rotating body (capping machine main body), and a capper is provided above each of the container holding means. The rotating body includes a container supply unit and a cap supply unit (not shown). While the container 3 fed from the container supply unit is held and rotated by the container holding unit, the cap 2 from the cap supply unit is provided. The cap 2 is configured to be wound around the mouth of the container 3 by the capper that holds the cap.
[0011]
The operation of the servo motor 1 is controlled by the control unit 5, and when a command torque of a required value is commanded from the control unit 5 to the servo motor 1, the servo motor 1 is driven to rotate by the command torque. The cap gripper 4 is rotated. The servo motor 1 can be provided with a reduction gear for rotating the spindle by appropriately reducing the motor rotation speed.
[0012]
As the cap 2, for example, a screw cap made of a synthetic resin having a cylindrical shape with a lid and provided with a screw portion that is screwed and fitted with a male screw formed in the container mouth portion on the inner surface side of the cylindrical portion is used. Can do. Further, as the synthetic resin cap, a cap having an opening indication function which is generally used can be used. As the opening indication function, for example, when the cap wound around the container mouth is turned in the opening direction, the lower part of the cap cylinder portion connected to the cap body by a large number of thin bridges is separated from the body side. Therefore, it is possible to use a cap that displays the opening. In the present invention, the cap 2 to be used is not limited to the above-described synthetic resin cap, and various caps can be used.
[0013]
In the present invention, the container 3 only needs to have a mouth portion that can be screwed and fitted over the cap 2, and the shape, size, and material are not limited, and various types of containers, For example, a synthetic resin container such as a PET bottle, a glass bottle, or a metal bottle can be suitably used.
[0014]
The cap gripping portion 4 is preferably fitted with the cap 2 as described above and has a winding chuck that prevents its fall and prevents its circumferential rotation. Usually, a large number of fine vertical grooves called knurling eyes (knurling) are formed on the outer peripheral surface of the synthetic resin cap, and the cap gripping portion 4 uses the vertical grooves on the fitted outer peripheral surface of the cap. The rotation of the cap can be prevented. Further, the cap gripping portion 4 is provided with a fitting means for preventing the cap 2 from inadvertently dropping by a fall prevention means such as a ball urged radially inward by a spring or rubber, for example. be able to.
In addition, the cap gripping portion 4 has a rotary lift shaft for moving up and down the winding chuck while rotating together with the spindle of the servo motor 1.
[0015]
The controller 5 is not particularly limited as long as it can execute torque control described later.
[0016]
FIG. 2 is a graph for explaining an example of a cap tightening method according to the present invention.
The features of the cap tightening method according to the present invention are the meshing torque (primary torque, see symbol A in FIG. 4) generated at the start of winding tightening, the torque (secondary torque) at which the male screw of the container and the screw portion of the cap contact each other. 4) (refer to reference sign B in FIG. 4), and quaternary torque other than the torque (third torque, see reference sign C in FIG. 4) that the upper end of the container mouth contacts the cap top surface packing part・ Inner plugs such as one-piece caps ・ Outer seal contact and pressing, etc.) Temporary winding tightening and screw search ・ Temporary winding tightening end point common to temporary winding tightening reaches the final tightening set torque and servo motor etc. When the end of the tightening is confirmed and the end of the tightening is confirmed, the final tightening end point is taken as the final tightening end point. In addition to the control for determining that only the container with the cap tightened within the range of the upper and lower limits of the monitoring torque upper limit and the range of the angle at which the cap has rotated is judged as a non-defective product and discharging the product out of the capper. is there.
[0017]
The upper and lower limits of each of the above are added with control that can be arbitrarily set, and can be adapted to various cap tightening. In addition, control capable of registering the setting for each product type and for each combination of the container and the cap is added to prevent an erroneous operation (non-defective product determination based on two elements of reaching the tightening torque and detecting the rotation angle).
[0018]
As shown in FIG. 2, in this example, the cap winding process is divided into sub-processes for screw search, temporary winding, stop, and final tightening. Note that the division of the cap winding process is not limited to this example, and the cap winding process may be divided into two or more sub-processes (before final tightening and final tightening). It is also possible to do.
[0019]
For the screw search, after the cap 2 held by the cap gripping part 4 comes into contact with the mouth of the container 3 while being rotated, the upper end of the male screw formed on the outer surface of the container mouth and the inner periphery of the cap 2 This is a capping operation until the lower end of the threaded portion formed on the surface comes into contact and screwing is started. In this screw search process, as shown in FIG. 2, the detected torque value is slightly increased at first by contact between the cap 2 and the container 3 and immediately decreases to show a small peak. . Thereafter, the torque monitoring value gradually increases.
[0020]
The next temporary winding is a capping operation in which the cap 2 which has started to be screwed and fitted to the male screw of the container 3 is screwed and fitted almost completely along the male screw. As shown in FIG. 2, the torque monitoring value in the temporary winding process gradually increases following the screw search process, and the screw portion of the cap 2 is screwed into the male screw of the container 3. When it reaches the end point and requires force for further tightening, it rapidly increases (quaternary torque). In the present invention, when the torque increases at the final stage of the temporary winding and reaches the temporary winding set torque (reference numeral D in FIG. 2), it is determined that the temporary winding is finished, and this is the temporary winding end point. D.
[0021]
The final tightening step is a capping operation in which the container 3 is sealed with the cap 2 by winding the temporarily tightened cap 2 with a stronger force. In the present invention, the final tightening end point is the time when the torque monitoring value reaches the final tightening set torque and the servo motor is stopped and the end of winding tightening is confirmed.
In the present invention, as shown in FIG. 2, the cap rotation angle from the temporary winding end point D to the final tightening end point is detected, and the monitoring torque and the cap rotation angle with respect to the final tightening set torque are determined in advance. A non-defective product or a defective product is determined depending on whether it falls within the set range.
[0022]
In this way, the cap tightening angle from the fourth torque to the third torque is detected, and whether or not the torque monitoring is within the preset upper and lower limits in the final tightening sub-step, and the tightening angle is set in advance. Judgment is made based on whether or not it falls within the range of the upper and lower limits, thereby making it possible to detect various defects described in the above problems 1 to 8 of the prior art, and to detect and discharge (discharge) defects in the capping process. Including an abnormal signal output to the apparatus), and it is possible to detect a winding-tight container and to prevent outflow.
[0023]
In order to further improve accuracy, the accumulated time from the end of temporary winding to final tightening is also detected, and the upper and lower limits of the monitoring torque relative to the final tightening set torque, the upper and lower limits of the angle at which the cap has rotated, and temporary It is desirable to add control for determining that only the cap winding container that falls within the upper and lower limits of the accumulated time from the winding fastening end point D to the final fastening finishing point is a non-defective product and discharging the product out of the capper. Each upper limit and lower limit can be set arbitrarily, and it is desirable to be able to cope with various types of cap tightening. In addition, control that allows registration of settings for each product type and for each combination of bottle and resin cap has been added. It is desirable to prevent it (determining a non-defective product based on three elements of reaching the tightening torque, detecting the rotation angle, and detecting the accumulated time)
[0024]
An example of the tightening control to which the cap tightening method according to the present invention is applied will be described with reference to FIG. In the winding tightening control shown in FIG. 2, upper and lower limits are set for each of the final tightening set torque, the rotation angle, and the accumulated time, and the cap tightening container that conforms to the upper and lower limits is determined as a non-defective product.
[0025]
For example, if the container or cap has a screw shape defect (crushing screw), the container and cap screw parts are damaged during tightening, a cap top surface packing part defective molded product is tightened, or one piece is tightened When there is a defect such as an inner plug insertion failure such as a cap or an outer seal biting, the tightening torque increases. These defects (shown as “screw crushing etc.” as an example in FIG. 2) have a faster torque increase than non-defective products (indicated by solid lines in FIG. 2), and the rotation angle is the lower limit of the rotation angle (lower limit angle). The final tightening set torque is reached before it reaches (). Accordingly, by performing the tightening management by setting the upper and lower limits of the rotation angle, even if the monitoring torque reaches the final tightening set torque, it is possible to determine that the rotation angle is insufficient as a defective product.
[0026]
In addition, a defective product (indicated as “oblique cover” in FIG. 2) in which the cap is tightened obliquely with respect to the male screw of the container mouth, which is so-called oblique cover, is indicated by temporary winding. At this stage, the monitoring torque becomes abnormally higher than that of the non-defective product, so that the final tightening torque is reached before the rotation angle reaches the lower limit (lower limit angle) of the rotation angle. Accordingly, by performing the tightening management by setting the upper and lower limits of the rotation angle, even if the monitoring torque reaches the final tightening set torque, it is possible to determine that the rotation angle is insufficient as a defective product.
[0027]
Further, when the chuck and the cap of the cap gripping part 4 slip, or when the container and the container fixing part slip, the monitoring torque value does not reach the final tightening set torque within the specified time (see “ Winding time is over "). For this defect, the winding tightening time is set, and those that do not reach the final tightening set torque within that time can be determined as defective.
Further, in the case of “no cap” in which the cap is not supplied to the chuck of the cap gripping portion 4, the monitoring torque does not increase, so that it can be easily determined as defective.
In addition to this, when a defective cap without packing is tightened, the angle until the upper end of the container touches the top of the cap increases, so the upper limit angle is exceeded, so the monitoring torque reaches the final tightening set torque. Even when the rotation angle is abnormal, it is possible to determine that the rotation angle is defective.
[0028]
The appropriate cap winding rotation angle from the temporary winding end point D to the final tightening end point can be calculated from the cap drawing. Furthermore, the approximate value can also be calculated by aligning the threading start of the container and the cap and tightening while watching the rotation angle.
[0029]
【The invention's effect】
As described above, according to the present invention, it is possible to easily and accurately carry out determination of various types of winding tightening defects that have been difficult to detect conventionally.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a cap winding apparatus for carrying out a cap winding method according to the present invention.
FIG. 2 is a graph illustrating the monitoring torque of a non-defective product and various defective products in the cap tightening method according to the present invention.
FIG. 3 is a graph illustrating a setting value and a monitoring value of a rotation speed in a conventional cap winding method.
FIG. 4 is a graph illustrating torque setting values and monitoring values in a conventional cap tightening method.
[Explanation of symbols]
1 Servo motor 2 Cap 3 Container (bottle)
4 Cap gripping part 5 Servo amplifier

Claims (1)

Cap tightening with a cap having a screw part that is screwed and fitted to a screw part formed in the container mouth part over the container mouth part using a capper having a servo motor capable of detecting and controlling the torque value In the method
The winding process is divided into at least the sub-processes before final tightening and final tightening.
When the torque monitoring value gradually increases and reaches the end point, it suddenly rises when more tightening force is required and reaches the temporary tightening set torque that is lower than the final tightening set torque. As a winding tightening end point, the sub-process before the final tightening is shifted to the final tightening sub-process at this point,
When the monitored value reaches the final tightening set torque and the servo motor stops and the end of winding tightening is confirmed, this is the final tightening end point.
A cap rotation angle from the end point of the temporary winding tightening to the end point of the final tightening is detected, and an integrated time from the end of the temporary winding tightening to the end of the final tightening is detected, the monitoring torque with respect to the final tightening set torque, the cap rotation A cap tightening method comprising: determining whether the winding is good or defective according to an angle and whether the accumulated time is within a preset range.

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