JP7572602B2 - Capping Device - Google Patents

Description

The present invention relates to a capping device, and more specifically to a capping device that tightens and attaches a cap to the mouth of a container.

Conventionally, a capping device is known that rotates a chuck holding a cap using a servo motor to tighten and attach the cap to the mouth of a container (for example, Patent Document 1).

JP 2002-308380 A

5(A), in the capping device of Patent Document 1, first, the cap 8 held by the chuck is lowered to the mouth 5C of the container 5 and placed thereon, so that the lower end 8A' of the threaded portion 8A of the cap 8 abuts from above against the threaded portion 5D of the mouth 5C of the container 5. This is the position where the two threaded portions 8A, 5D start to mesh with each other.
Next, the cap 8 is rotated in the tightening direction by the servo motor via the chuck with a predetermined capping torque, whereby the threaded portion 8A of the cap 8 engages with the threaded portion 5D of the container 5 and is tightened, and the release ring 8B at the bottom end of the cap 8 passes over the inner ring 5E of the mouth 5C of the container 5, completing the attachment of the cap 8 to the mouth 5C of the container 5.
However, as described above, when the cap 8 is lowered to cover the mouth 5C of the container 5 and the lower end 8A' of the threaded portion 8A of the cap 8 is brought into contact with the threaded portion 5D of the container 5 from above, the lower end 8A' of the threaded portion 8A of the cap 8 may jump over the threads of the threaded portion 5D of the container 5 and fall onto the threads one step below, resulting in "thread drop" (see FIG. 5(B)). When this "thread drop" occurs, the impact of the cap 8 dropping causes the liquid level 9A of the filling liquid 9 in the container 5 to splash, causing the filling liquid 9 to adhere to the threaded portions 8A and 5D, resulting in the problem that the cap 8 and the threaded portions 8A and 5D of the container 5 are contaminated by the filling liquid 9 after attachment is completed.
In addition, with the recent trend towards lighter containers and caps, if the threaded portions of the container or cap do not have sufficient strength, there has been a problem that the threaded portions of the container or cap can be damaged by the impact caused by the aforementioned "screw drop-out."

In view of the above circumstances, the present invention as set forth in claim 1 provides a capping apparatus comprising: a conveying means for conveying containers; a capping head for attaching a cap to an opening of the container conveyed by the conveying means; a motor for rotating the capping head; a lifting mechanism for raising and lowering the capping head; and a control device for controlling the operation of the motor,
In a capping device, a capping head holding a cap is lowered by a lifting mechanism to bring a lower end of a screw part of the cap into contact with a screw part of a mouth of a container, and then the cap is rotated via the capping head by the motor to be fastened around the mouth of the container,
an acceleration sensor provided on the capping head for detecting an acceleration when the cap is lowered;
The control device is characterized in that, based on the change in acceleration detected by the acceleration sensor, it determines whether or not a screw drop has occurred, in which the lower end of the threaded portion of the cap abuts against the threads of the mouth of the container and then drops to the threads directly below the abutting thread .
The present invention as set forth in claim 2 provides a capping device comprising: a conveying means for conveying containers; a capping head for attaching a cap to an opening of the container conveyed by the conveying means; a motor for rotating the capping head; a lifting mechanism for raising and lowering the capping head; and a control device for controlling the operation of the motor,
A capping device which uses a lifting mechanism to lower a capping head holding a cap, brings the lower end of the screw part of the cap into contact with the screw part of the mouth of a container, and then rotates the cap via the capping head using the motor to tighten the cap around the mouth of the container, comprises an acceleration sensor which detects the acceleration of the cap when it is lowered,
The conveying means includes a gripper for gripping a container,
The acceleration sensor is provided in the gripper,
The control device is characterized in that, based on the change in acceleration detected by the acceleration sensor, it determines whether or not a screw drop has occurred, in which the lower end of the threaded portion of the cap abuts against the threads of the mouth of the container and then drops to the threads directly below the abutting thread .

This configuration makes it possible to reliably detect containers that have a "missing screw step" when attaching a cap to a container, and to reliably reject defective containers that have a missing screw step.

FIG. 1 is a plan view showing an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view of a main part of the capping device of FIG. 1 . 3A and 3B are diagrams showing the change in the closing torque by the servo motor in FIG. 2 and the change in the detected value of the acceleration sensor, in which FIG. 3A shows a normal case in which no "screw dropout" occurs, and FIG. 3B shows a case in which "screw dropout" occurs. FIG. 4 is a vertical cross-sectional view showing a second embodiment of the present invention. 5A and 5B are cross-sectional views for explaining the problems of the conventional technology, in which FIG. 5A shows a case where a "screw drop-out" does not occur, and FIG. 5B shows a case where a "screw drop-out" occurs.

The present invention will now be described with reference to the illustrated embodiment. In Figures 1 and 2, reference numeral 1 denotes a filling system, which includes a rotary filler 2 having a plurality of filling valves (not shown) arranged at equal pitches around its periphery, and a rotary capping device 4 having a plurality of capping heads 3 arranged at equal pitches around its periphery.
While the filler 2 and the capping device 4 are rotating in the direction of the arrow, an empty container 5 is supplied below each filling valve of the filler 2 by a supply wheel (not shown), and each container 5 is gripped by a gripper (not shown) provided on the filler 2 and filled with a predetermined amount of filling liquid by the filling valve. Each container 5 filled with filling liquid by the filling valve of the filler 2 is released from the gripper of the filler 2 and is transferred from the filler 2 to the capping device 4 via the intermediate wheel 6.

The capping device 4 has capping heads 3 which hold caps 8 by chucks 7 at equally spaced positions on the outer periphery, and has an open/close gripper 4A below each capping head 3 which grips the neck 5A of the container 5.
The container 5 delivered from the intermediate wheel 6 is filled with the filling liquid 9, as shown in Fig. 5(A), and the liquid level 9A is located slightly below the flange 5B of the neck 5A. The container 5 is gripped on both sides of the neck 5A by the grippers 4A, and is supported by the flange 5B formed on the neck 5A, so that it can be transported at a predetermined height (see Fig. 2).
Also, similar to what is shown in Figure 5, a threaded portion 5D is formed on the outer periphery of the mouth 5C of the container 5, while a threaded portion 8A is formed on the inner periphery of the cap 8, which is screwed into the threaded portion 5D of the container 5, similar to what is shown in Figure 5.
Furthermore, an inner ring 5E is formed between the flange portion 5B and the threaded portion 5D of the container 5, while a release ring 8B is provided at the lower end of the cap 8.
As the capping device 4 rotates in the direction of the arrow, the capping head 3 is lowered by the lifting mechanism 11, and the chuck 7 is rotated in the tightening direction with a predetermined capping torque by the servo motor 12 provided for each capping head 3, so that the cap 8 held by the chuck 7 is lowered and placed on the mouth 5C of the container 5, and then tightened and attached. The process from lowering the cap 8 to rotating it to complete attachment is the same as the conventional technology described with reference to Figure 5(A).
Thereafter, the container 5 with the cap 8 attached by each capping head 3 of the capping device 4 is released from the gripper 4A gripping the neck 5A and is gripped by the discharge wheel 13 and discharged from the capping device 4 onto the discharge conveyor 14, and then is transported by the discharge conveyor 14 downstream toward a processing device not shown.
As will be described in more detail later, in this embodiment, when each capping head 3 of the capping device 4 has finished attaching the cap 8 to the container 5, the occurrence of the aforementioned "screw drop-out" can be determined by the control device 16 based on the measurement value of the acceleration sensor 15.
A reject mechanism 17 is disposed in the middle of the transport path of the discharge conveyor 14, which forcibly removes defective containers 5 from the discharge conveyor 14. Any container 5 determined by the control device 16 to be a defective product having a "missing screw step" is forcibly removed from the discharge conveyor 14 by the reject mechanism 17 during the process of being transported on the discharge conveyor 14.

The capping device 4 includes a rotating body 18 that rotates clockwise, a plurality of capping heads 3 arranged at equal pitch in the circumferential direction around the outer periphery of the rotating body 18, and a gripper 4A arranged below the capping heads 3 and configured to grip the neck 5A of the container 5.
The rotating body 18 and the multiple grippers 4A provided thereon constitute a conveying means for conveying the container 5. As described above, the neck portion 5A of the container 5 is gripped by the grippers 4A and the flange portion 5B is supported, and in this state, the container 5 is conveyed as the rotating body 18 rotates.

As shown in Figure 2, the capping head 3 includes a cylindrical outer tube 21 that is arranged to be able to rise and fall on the outer periphery of the rotating body 18, a spindle 22 that is arranged inside the outer tube 21 to be able to rotate and rise and fall freely, a chuck 7 attached to the lower end of the spindle 22 and holds the cap 8 in a removable manner, an inner tube 23 that is connected to the upper end of the spindle 22 and has a spline groove formed on its inner periphery, a spline shaft 24 that is spline-fitted into the spline groove of the inner tube 23, a servo motor 12 connected to the upper end of the spline shaft 24, and an acceleration sensor 15 attached to the outer periphery of the lower end of the outer tube 21.
The inner cylinder 23, spindle 22 and chuck 7 are capable of ascending and descending relative to the outer cylinder 21, and are supported by a step 21A of the outer cylinder 21. A spring 26 is elastically mounted between the flange 22A on the spindle 22 side and the step 21A inside the outer cylinder 21 that faces it. The spindle 22 and the chuck 7 provided at its lower end are constantly urged downward relative to the outer cylinder 21 by the elastic force of the spring 26.
A cam follower 27 is attached to the inside of the upper part of the outer cylinder 21, and this cam follower 27 is rollably engaged with a cam groove 28A of an annular cam 28 disposed along the outer periphery of the rotating body 18. The annular cam 28 and the cam follower 27 constitute a lifting mechanism 11 that lifts and lowers the chuck 7.
As the rotating body 18 rotates in the direction of the arrow in Figure 1, the capping head 3 is raised and lowered by the lifting mechanism 11 at the required position in the rotation section, and the chuck 7 is rotated in the tightening direction with a predetermined capping torque by the servo motor 12.

The operation of the servo motor 12 is controlled by a control device 16, and when the chuck 7 is lowered by the lifting mechanism 11 from the upper end to the lower end and the lower end 8A' of the screw portion 8A of the cap 8 abuts against the screw portion 5D of the container 5 from above, the control device 16 drives the servo motor 12 to rotate with a predetermined capping torque.
An encoder 31 that outputs a pulse signal is connected to the rotating part of the servo motor 12, and an ammeter 32 that detects the output current of the servo motor 12 is also connected to the rotating part of the servo motor 12. When the servo motor 12 is driven to rotate, the pulse signal output from the encoder 31 is input to the control device 16, and the current output from the servo motor 12 is detected by the ammeter 32 and input to the control device 16.
The control device 16 is adapted to recognize the rotation angle and rotation speed of the servo motor 12 based on the pulse signal detected by the encoder 31. The control device 16 also detects the closing torque acting on the chuck 7 from the current value detected by the ammeter 32 after the servo motor 12 is rotated and records it in chronological order.
The acceleration sensor 15 provided on the outer tube 21 of the capping head 3 is adapted to detect the acceleration of the cap 8 from the time the capping head 3 is lowered from the upper end to the lower end by the lifting mechanism 11 until the installation of the cap 8 is completed, and the acceleration detected by the acceleration sensor 15 is input to the control device 16 at any time.
In this embodiment, the acceleration of the cap 8 when it is lowered by the lifting mechanism 11 is detected by the acceleration sensor 15, and based on the detected value, the control device 16 determines whether or not the aforementioned "screw step drop" has occurred.

In the above-described configuration, the controller 16 determines whether or not the cap has been attached and when the attachment has been completed as follows.
The details of the process of attaching the cap 8 to the mouth portion 5C of the container 5 by the capping device 4 are similar to those described above with reference to FIG. 5(A).
That is, first, as the container 5 gripped by the gripper 4A is transported with the rotation of the rotor 18, the capping head 3 with the cap 8 held by the chuck 7 is lowered by the lifting mechanism 11 from the upper end to the lower end shown in Fig. 2. As a result, the cap 8 held by the chuck 7 is placed on the mouth 5C of the container 5, the lower end 8A' of the screw portion 8A of the cap 8 abuts against the threads of the screw portion 5D of the container 5 from above, and the cap 8 is pressed downward toward the mouth 5C of the container 5 by the resilient force of the spring 26 (the same state as Fig. 5(A)).
From this state, the servo motor 12 is rotated, causing the cap 8 to rotate in the tightening direction via the chuck 7 with a predetermined capping torque, so that the screw portion 8A of the cap 8 engages with the screw portion 5D of the container 5 and then is tightened, and the release ring 8B of the cap 8 overcomes the inner ring 5E of the container 5, completing the attachment of the cap 8 to the mouth 5C of the container 5.
Here, the acceleration of the cap 8 as it descends from the time the lifting mechanism 11 starts to lower the cap 8 until it reaches its lowering end and the time the installation of the cap 8 is completed is detected by the acceleration sensor 15 and input to the control device 16.
Figure 3 (A) shows the relationship between the detected acceleration value and the capping torque when no "screw dropout" occurs when attaching the cap 8, and Figure 3 (B) shows the relationship when "screw dropout" occurs when attaching the cap 8.
As shown in Figure 3 (A), when the installation of the cap 8 is completed without the occurrence of "screw drop-out" (a good container), the acceleration G1 increases at the point when the release ring 8B of the release cap 8 passes over the inner ring 5E of the container 5, but the acceleration is zero (constant) during the installation process other than that point.
Looking at this in terms of fluctuations in capping torque, the capping torque T1 when the cap 8 is not rotated and the lower end 8A' of the threaded portion 8A is in contact with the threaded portion 5D of the container 5 is zero, but the torque values then become larger at the torque T2 at the start of engagement when the cap 8 begins to be rotated, the torque T3 in the subsequent pre-tightening process, the torque T4 in the final tightening process, and then the torque T5 at the end of tightening.
Then, immediately after the final fastening process indicated by the torque T4, the separation ring 8B passes over the inner ring 5E, whereby the acceleration G1 is detected.
The control device 16 detects acceleration G1 after the final tightening process indicated by torque T4, and since there is no fluctuation in acceleration during the rest of the installation process (the acceleration is zero), in this case no "screw drop-out" occurs, and the control device 16 determines that the container 5 with the cap 8 attached is a good product.
In contrast, if the "screw dropout" shown in FIG. 5B occurs when attaching the cap 8, the detection value by the acceleration sensor 15 will be as shown in FIG. 3B.
In other words, when looking at the fluctuations in the capping torque, the capping torque T1 is zero when the lower end 8A' of the threaded portion 8A abuts the threaded portion 5D of the container 5 without the cap 8 being rotated, but then, immediately after the torque T2 at the start of engagement when the cap 8 begins to rotate, a suddenly large acceleration GX is detected.
This is because, when the "screw step drop" shown in FIG. 5(B) occurs, the lower end 8A' of the screw portion 8A of the cap 8, which is pressed by the spring 16, comes into contact with the threads of the screw portion 5D of the container 5 and suddenly drops onto the threads one step below, resulting in a suddenly large acceleration GX that is detected.
Thereafter, the torque value increases to torque T3 in the temporary fastening process after the start of meshing, to torque T4 in the final fastening process, and then to torque T5 at the end of attachment.
Here, when "screw step drop" occurs, the time that elapses from when the cap 8 is rotated in the tightening direction to when the installation of the cap 8 is completed is shortened by the amount of one step of the screw thread. Therefore, when "screw step drop" occurs, the timing at which the acceleration G1 when the inner ring 5E is separated and the ring 8B passes over it is detected is earlier than when "screw step drop" does not occur as shown in Fig. 3(A) and the time that elapses from when the rotation of the cap 8 is started to when the installation of the cap is completed is also shorter (see Figs. 3(A) and 3(B)).
Then, in Figure 3 (B), if a large acceleration GX is detected at a point before the acceleration G1 at which the inner ring 5E is separated and the ring 8B passes over it, specifically, immediately after the torque T2 at the start of engagement is detected, the control device 16 is configured to determine that a ``screw drop-out'' has occurred in the container 5 to which the cap 8 is attached.
As described above, defective containers 5 that have a "dropped screw" are forcibly removed from the discharge conveyor 14 by the reject mechanism 17 while being transported by the discharge conveyor 14.

As described above, the capping device 4 of this embodiment is equipped with an acceleration sensor 15 on the capping head 3, which detects the acceleration from when the cap 8 is lowered until it is completely attached to the container 5, and based on the detection value of this acceleration sensor 15, the control device 16 can reliably determine whether or not a "screw drop-out" has occurred.
Therefore, the container 5 determined by the control device 16 to be a defective product having a "missing screw step" is reliably removed from the discharge conveyor 5 by the reject mechanism 17. This makes it possible to prevent the defective container 5 from being transported to a downstream processing device (packing device).
As described above, containers 5 with "missing threads" have hygiene problems because the filling liquid 9 splashes onto the threaded portions 5D and 8A, and cannot be sold commercially as products. In this embodiment, it is possible to reliably prevent such defective containers 5 from being distributed on the market.

4 shows a second embodiment of the present invention, in which the acceleration sensor 15 is provided not in the capping head 3 but in the gripper 4A that grips the container 5. The other configurations are the same as in the first embodiment described above, and the same member numbers are used to designate corresponding members.
In this second embodiment, if a "screw drop" occurs when the cap 8 held by the chuck 7 is lowered to cover the mouth 5C of the container 5, the drop is detected by the acceleration sensor 15 via the gripper 4A holding the container 5, and is detected as a large fluctuation in acceleration, similar to the case shown in Fig. 3(B). Based on this, the control device 16 determines that the container 5 is a defective product in which a "screw drop" has occurred. Even with the second embodiment having such a configuration, it is possible to obtain the same actions and effects as the first embodiment.

The position where the acceleration sensor 15 is provided in the capping device 4 is not limited to the positions in the above-mentioned embodiments, and the acceleration sensor 15 may be provided on the spindle 22 or chuck 7 of the capping head 3.

3: Capping head 4: Capping device 4A: Gripper 5: Container 5C: Mouth 5D: Screw portion 7: Chuck 8: Cap 8A: Screw portion 8A': Lower end 11: Lifting mechanism 12: Servo motor 15: Acceleration sensor 16: Control device 18: Rotating body (transport means) GX: Acceleration

Claims (3)

The apparatus comprises a conveying means for conveying a container, a capping head for attaching a cap to an opening of the container conveyed by the conveying means, a motor for rotating the capping head, a lifting mechanism for raising and lowering the capping head, and a control device for controlling the operation of the motor,
In a capping device, a capping head holding a cap is lowered by a lifting mechanism to bring a lower end of a screw part of the cap into contact with a screw part of a mouth of a container, and then the cap is rotated via the capping head by the motor to be fastened around the mouth of the container,
an acceleration sensor provided on the capping head for detecting an acceleration when the cap is lowered;
The control device is a capping device characterized in that it determines, based on the change in acceleration detected by the acceleration sensor, whether or not a screw drop has occurred, in which the lower end of the threaded portion of the cap abuts against the thread of the mouth of the container and then falls onto the thread directly below the abutting thread . The apparatus comprises a conveying means for conveying a container, a capping head for attaching a cap to an opening of the container conveyed by the conveying means, a motor for rotating the capping head, a lifting mechanism for raising and lowering the capping head, and a control device for controlling the operation of the motor,
A capping device which uses a lifting mechanism to lower a capping head holding a cap, brings the lower end of the screw part of the cap into contact with the screw part of the mouth of a container, and then rotates the cap via the capping head using the motor to tighten the cap around the mouth of the container, comprises an acceleration sensor which detects the acceleration of the cap when it is lowered,
The conveying means includes a gripper for gripping a container,
The acceleration sensor is provided in the gripper,
The control device is a capping device characterized in that it determines, based on the change in acceleration detected by the acceleration sensor, whether or not a screw drop has occurred, in which the lower end of the threaded portion of the cap abuts against the thread of the mouth of the container and then falls onto the thread directly below the abutting thread . The capping device according to claim 1 or 2, characterized in that, when a sudden change in acceleration is detected by the acceleration sensor immediately after the lower end of the threaded portion of the cap comes into contact with the threads of the threaded portion of the container after the cap is lowered, the control device determines that the screw has fallen off.

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