JP2003081387A - Method of screwing cap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of screwing a cap with which a failure in screwing the cap can be reliably identified to distinguish bad products from good products. SOLUTION: The method of screwing a cap using a capper including a servo motor which can detect and control a torque value comprises a screwing process divided at least into respective sub-processes before properly screwing and a sub-process of properly screwing. A sub-process before the proper screwing is made to proceed to a sub-process of proper screwing with a point in time when a monitored value of torque reaches torque specified for provisionally screwing lower than torque specified for the proper screwing as a completion point of the provisional screwing. With a point in time when the monitored value reaches the torque specified for the proper screwing and the servo motor stops to identify the completion of the provisional screwing as a point of completion of the proper screwing, a cap rotation angle from the completion of the provisional screwing to the completion of the proper screwing is detected. The method includes a step of determining whether the cap is good or defective based on whether the monitored torque for the torque specified for the proper screwing and the cap rotation angle are within predetermined ranges.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention arranges a cap having a threaded portion screwed into a threaded portion formed in a container mouth portion on a capper equipped with a servomotor capable of detecting and controlling a torque value. The present invention relates to a cap winding method for covering the container mouth with the cap and tightening the cap.

[0002]

2. Description of the Related Art Conventionally, a method disclosed in Japanese Patent Publication No. 6-76107 is known as a method for controlling a capping torque when a cap is screwed on a container. In the method described in the above publication, in a capper using a torque motor, when the cap is tightened on a container and the rotation of the capping head is reduced, the deceleration of the capping head becomes a predetermined value. To control the command torque to maintain the inertia torque of the capping head substantially constant, and to tighten the cap to the container with a command torque of a magnitude obtained by subtracting the inertia torque of the capping head from the predetermined capping torque. Is to be terminated.

Further, in tightening the cap, a plurality of stages having different proper torque values are required, that is, the screw of the cap is searched for until the screw part of the cap is covered with the male screw of the cap, and the screw of the cap is screwed. There are temporary winding tightening in which is smoothly screwed and fitted along the male screw of the container mouth, and final final tightening, and it is desirable to change the winding tightening condition for each of these sub-processes. FIG. 3 is a diagram for explaining a case where a capper equipped with a servo motor or the like is used, 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 fluctuation of the torque value in the winding tightening process shown in FIG. In this method, according to the above-mentioned conventional technique, the cap is wound by using the specified rotation speed. That is, it is presumed that the upper end of the container comes into contact with the packing surface inside the resin cap when the screw search step Arpm, the temporary tightening step Brpm, and the final tightening step Crpm are individually set and the monitored speed decreases from the set values. Then, the winding tightening process is switched or the winding tightening is completed. For example, as shown in FIG. 3, when the monitoring value of the rotation speed reaches a preset rotation speed P, the temporary winding fastening step is switched to the final fastening step.

Conventionally, when the tightening of the cap around the container by the servo motor or the like and the determination of non-defective products are completed, when the set torque is reached, the clutch is actuated to end the torque transmission or the servo motor is stopped. It was controlled by, and the end of winding and the non-defective product were judged.

[0005]

However, with the above-described conventional control method, it is impossible to reliably detect whether or not the upper end of the container mouth portion comes into contact with the cap top surface packing portion. Further, in the conventional control method, since it is not possible to detect the angle at which the cap is tightened at the container mouth, in order to measure the tightening angle, after opening the cap of the container after tightening, measure the tightening angle, It was judged good or bad.

The problems in the prior art are as follows: If the screw shape from the container or cap is defective, the tightening torque may increase, and it may not be possible to make contact with the specified top packing part, and it may not be possible to ensure the hermeticity. 2. If the container and the screw part of the cap are damaged during tightening, the tightening torque may increase, and the specified top surface packing part may not be contacted, so that the hermeticity may not be ensured. 3. When the cap top surface packing part defective molded product is wound and tightened, the tightening torque may increase, and the specified top surface packing part may not be contacted, and the sealing performance may not be secured. 4. When the cap is diagonally covered during tightening, the tightening torque may increase, and it may not be possible to make contact with the specified top surface packing part, so that the hermeticity may not be ensured. 5. When tightening the winding, when inserting the inner plug such as a one-piece cap or when the outer seal is caught, the tightening torque may increase, and it may not be possible to make contact with the specified top packing, thus failing to ensure the sealing performance. 6. If slip occurs between the winding chuck and the cap, the winding process ends without reaching the required torque. 7. When slipping occurs between the container and the container fixing portion during winding, the winding process ends without reaching the required torque. 8. When different caps with different filling and sterilizing conditions are mixed, the tightening is performed under the different conditions, so the sealing performance cannot be secured.

When the above problems occur, it is impossible to detect defects in the middle of winding by the conventional method, and it is difficult to judge the appearance by visual inspection, and there is a possibility that the product may be discharged as a non-defective product. The present invention has been made in view of the above circumstances, and an object thereof is to provide a cap winding method that can reliably identify a cap winding defective product and distinguish it from a non-defective product.

[0008]

In order to achieve the above object, the present invention is capable of detecting and controlling a torque value of a cap having a threaded portion which is screwed and fitted into a threaded portion formed in a container mouth. In a cap tightening method for covering and tightening a container mouth portion using a capper equipped with a servomotor, the winding tightening step is divided into at least each of sub-steps of final tightening and final tightening. , When the torque monitoring value reaches the temporary tightening set torque that is lower than the final tightening set torque, the process proceeds to the final tightening sub-process as the temporary winding end point, and the monitoring value reaches the final tightening set torque and the servo motor The final tightening end point is the point at which the end of the final tightening is confirmed after stopping, and the cap rotation angle from the temporary tightening end point to the final tightening end point is detected to determine the final tightening set torque. Providing cap tightening method which is characterized in that the determination of good or defective depending on whether or not within the scope of monitoring the torque and the cap rotation angle set in advance.

In the cap winding method of the present invention, it is preferable to further include a criterion for detecting an integrated time from the end of the temporary winding to the end of the final tightening and determining whether or not it falls within a preset integrated time range. .

[0010]

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 is mainly configured to include a servo motor 1, a cap gripping portion 4 provided at a tip of a spindle of the servo motor 1, and a control unit 5 such as a servo amplifier for controlling the servo motor 1. ing. With this capper, the cap 2 held by the cap gripping portion 4 can be covered on the mouth of the container 3, screwed and fitted in the closing direction, and wound to tighten the container mouth. There is. Although not shown in detail in the capper, container holding means are provided on the outer periphery of the rotating body (capping machine body) at equal intervals, and cappers are provided above these container holding means, respectively. The rotator includes a container supply means and a cap supply means (not shown). While the container 3 sent from the container supply means is held and rotated by the container holding means, the cap 2 from the cap supply means is supplied. The cap 2 is configured to be wound around the mouth of the container 3 by the capper.

The operation of the servo motor 1 is controlled by the control unit 5. When the control unit 5 issues a command torque of a required value to the servo motor 1, the servo motor 1 outputs the command torque. The cap gripping portion 4 is driven to rotate by the rotation of the cap gripping portion 4. The servomotor 1 can be provided with a speed reducer or the like for rotating the spindle by appropriately reducing the motor rotation speed.

The cap 2 is, for example, a synthetic resin screw cap having a cylindrical shape with a lid, and a screw portion for screwing and fitting a male screw formed in the container mouth portion is provided on the inner surface side of the cylindrical portion. Can be used. Further, as the synthetic resin cap, one having an opening display function, which is widely used, can be used. As an opening display function, for example, when the cap wound around the container mouth is turned in the opening direction, the lower part of the cap tube part that was connected to the cap body by many thin bridges is disconnected from the body side. It is possible to use a type of cap that indicates the opening by opening. In the present invention, the cap 2 used is not limited to the synthetic resin cap described above, and various caps can be used.

Further, in the present invention, the container 3 is not limited in shape, size and material as long as it has a mouth portion which covers the cap 2 and can be screwed and fitted, and various types. Containers such as synthetic resin containers such as PET bottles, glass bottles and metal bottles can be preferably used.

It is preferable that the cap gripping portion 4 has a winding chuck that fits the cap 2 as described above, prevents the cap 2 from falling, and prevents rotation in the circumferential direction. Usually, a large number of fine vertical grooves called knurls are formed on the outer peripheral surface of the synthetic resin cap, and the cap gripping portion 4 is formed by utilizing the vertical grooves on the fitted outer peripheral surface of the cap. The cap can be prevented from rotating. Further, the cap gripping portion 4 is provided with a fitting means for preventing the cap 2 from being accidentally dropped by a fall prevention means such as a ball urged radially inward by a spring or rubber. be able to. Further, the cap gripping portion 4 has a rotary lifting shaft for lifting the winding chuck while rotating with the spindle of the servo motor 1.

The control unit 5 is not particularly limited as long as it can execute the torque control described later.

FIG. 2 is a graph for explaining an example of the cap tightening method according to the present invention. The cap tightening method according to the present invention is characterized by a meshing torque (primary torque, see reference symbol A in FIG. 4) generated at the start of winding, and a torque (secondary torque) at which a male screw of a container and a screw part of a cap come into contact with each other. , Refer to symbol B in FIG. 4), and quaternary torque other than the torque (the third torque, refer to symbol C in FIG. 4) at which the upper end of the container opening portion contacts the cap top surface packing portion (cap side contact with the side seal portion and pushing)・ Temporary winding and searching for screws due to factors such as contact and pushing of inner plug / outer seal of one-piece cap, etc. ・ Temporary winding end point of common winding that is common to temporary winding is reached. Stop and the end of the final tightening is confirmed as the final end of the final tightening, and control is added to detect the angle at which the cap is rotated by the final tightening chuck during the final tightening setting. In addition to the control that discharges the product to the outside of the capper by judging only the container with the cap wound within the upper and lower limits of the monitoring torque and the upper and lower limits of the rotation angle of the cap is there.

The upper and lower limits of each of the above are added with a control that can be arbitrarily set, so that various caps can be wound and tightened. In addition, a control that allows the setting to be registered for each product type and each combination of container and cap is added to prevent erroneous operation.
Determining non-defective products by factors).

As shown in FIG. 2, in this example, the cap winding step is divided into sub-steps of screw search, temporary winding, stop and final tightening. The division of the cap tightening process is not limited to this example, and the cap tightening process may be divided into two or more sub-processes (before the main tightening and the main tightening). It is also possible to do so.

To search for a screw, the cap 2 held by the cap gripping portion 4 comes into contact with the mouth of the container 3 while being rotationally driven, and then the upper end of the male screw formed on the outer surface of the container mouth and the cap 2 The capping operation is performed until the lower end of the threaded portion formed on the inner peripheral surface of the contact portion comes into contact and the screw-fitting is started. In this screw searching step, as shown in FIG. 2, the detected torque value is the cap 2 and the container 3
Upon contact with, the torque value rises slightly at first, then immediately decreases and shows a small peak. After that, the monitoring value of torque gradually increases.

The next temporary winding fastening 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 almost completely screwed and fitted along the male screw. As shown in FIG. 2, the torque monitoring value in the temporary winding step is gradually increased following the screw searching step, and the threaded portion of the cap 2 is screwed and fitted to the male thread of the container 3. ,, when it reaches the end point and a force is required for further winding tightening, it rapidly rises (fourth torque). In the present invention, when the torque increases in 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 determined as the temporary winding end point. D.

In the final tightening step, the cap 2 temporarily tightened is used.
Is a capping operation in which the container 3 is sealed with the cap 2 by further tightening with a strong force. In the present invention, the time point when the torque monitoring value reaches the final tightening set torque, the servo motor stops, and the end of the winding tightening is confirmed is defined as the final tightening end point. 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 detected in advance. A good product or a defective product is determined depending on whether or not it falls within the set range.

In this way, the cap tightening angle from the fourth torque to the third torque is detected, and in the main tightening sub-process, whether or not the torque monitoring falls within a preset upper and lower limit range, and the tightening angle. It is possible to detect various defects described in the above-mentioned problems 1 to 8 of the conventional technique by determining whether or not the value falls within a range of preset upper and lower limits. Ejection (including output of abnormal signal to ejection device)
This makes it possible to detect a container that is not tightly wound and prevent outflow.

In order to further improve the accuracy, the integrated time from the temporary winding end point to the final tightening is also detected, and the upper and lower limit range of the monitoring torque with respect to the final tightening set torque,
Only cap cap containers that fall within the upper and lower limits of the angle that the cap rotates and the upper and lower limits of the accumulated time from the temporary winding end point D to the final tightening end point are judged to be non-defective, and then placed outside the capper. It is advisable to add controls to discharge the product. Each upper and lower limit can be set arbitrarily, and it is desirable to be able to respond to various cap tightening.Furthermore, a control that can register the setting for each product type and each combination of bottle and resin cap has been added to make mistaken operation. It is desirable to prevent it (defective product determination by three factors: reaching the tightening torque, detecting the rotation angle, and detecting the integrated time).

An example of winding tightening control to which the cap winding method according to the present invention is applied will be described with reference to FIG. Figure 2
In the tightening control shown in (1), the upper and lower limits are set for the main tightening set torque, the rotation angle, and the integrated time, and a cap tightening container that conforms to them is determined as a good product, and a product outside the range is determined as a defective product.

For example, when the screw shape defect (screw crushing) originating from the container or the cap is damaged, the screw part of the container and the cap is damaged during tightening, when the cap top surface packing part defective molded product is wound, or wound. If the one-piece cap or other inner plug is not properly inserted or the outer seal is caught when tightening, the tightening torque will increase. For these defects (indicated as "screw crushing etc. in FIG. 2 as an example"), the torque increases faster than the non-defective product (shown by the solid line in FIG. 2), and the rotation angle is the lower limit (lower limit angle) of the rotation angle. ) Is reached before the final tightening set torque is reached. Therefore, by setting the upper and lower limits of the rotation angle and performing the winding tightening management, even if the monitoring torque has reached the final tightening set torque, a product with an insufficient rotation angle can be determined as a defective product.

Further, a defective product in which the cap is wound in a state in which the cap is inclined with respect to the male screw of the container mouth, that is, a so-called oblique covering is produced (indicated as "oblique covering" in FIG. 2).
In the case of the temporary tightening, the monitoring torque becomes abnormally higher than that of the non-defective product, so that the rotation angle reaches the final tightening set torque before it reaches the lower limit (lower limit angle) of the rotation angle. Therefore, by setting the upper and lower limits of the rotation angle and performing the winding tightening management, even if the monitoring torque has reached the final tightening set torque, a product with an insufficient rotation angle can be determined as a defective product.

Further, when the chuck of the cap gripping part 4 and the cap 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 (Fig. It is displayed as "Time over tightening" in 2). For this defect, the winding tightening time is set, and it is possible to determine that one that does not reach the final tightening set torque within that time is determined to be 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 to be defective. In addition to this, when a defective cap without packing is tightened, the angle at which the upper end of the container hits the top of the cap increases, so the upper limit angle is exceeded, so even if the monitoring torque reaches the final tightening set torque. However, even if the rotation angle is abnormal, it can be determined that the product having the abnormal rotation angle is defective.

An approximate value of the proper 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 be calculated by aligning the screw start of the container and the cap and tightening while watching the rotation angle.

[0029]

As described above, according to the present invention, it is possible to easily and accurately determine various defective winding tightening products, which have been difficult to detect conventionally.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a cap tightening device for carrying out a cap tightening method according to the present invention.

FIG. 2 is a graph illustrating monitoring torques of non-defective products and various defective products in the cap winding method according to the present invention.

FIG. 3 is a graph illustrating a set value and a monitored value of a rotation speed in a conventional cap winding method.

FIG. 4 is a graph exemplifying torque set values and monitoring values in a conventional cap winding method.

[Explanation of symbols]

1 Servo motor 2 cap 3 containers (bottles) 4 Cap grip 5 Servo amplifier

Claims (2)

[Claims] 1. A cap having a threaded portion screwed into a threaded portion formed at the container mouth is covered with the cap using a capper equipped with a servomotor capable of detecting and controlling a torque value. In the cap tightening method for tightening the winding, the winding tightening process is divided into at least each of the pre-tightening sub-processes and the main tightening sub-process. The time when the set torque is reached is used as the temporary tightening end point, and the main tightening sub-process is entered, and the time when the monitoring value reaches the set final tightening torque and the servo motor is stopped and the end of the tightening is confirmed. Point, the cap rotation angle from the temporary winding end point 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 preset. Cap tightening method which is characterized in that the determination of good or defective depending on whether or not fall within the defined range. 2. The cap tightening method according to claim 1, further comprising a criterion for detecting an integrated time from the end of the temporary tightening to the end of the final tightening, and determining whether or not it falls within a preset integrated time range. .