JP7554978B2 - Inspection device and inspection method - Google Patents

Description

The present invention relates to an inspection device and an inspection method for inspecting the outer diameter of a container, and in particular to an inspection device and an inspection method for measuring the outer diameter of a container by clamping the container between a fixed part and a movable part.

Plastic containers are formed, for example, by blow molding, but maintaining the dimensional precision of the molded containers is a major challenge. For example, if there is variation in the height of the thread formed on the mouth of the container, it can cause problems such as capping or sealing problems when attaching the cap after filling the container, so inspection is essential during the container production process.

As a method for inspecting containers, for example, inspection using images is being considered (see, for example, Patent Document 1, etc.). Patent Document 1 discloses a method in which multiple reference images are taken of the mouth of a normal container at successively different angles in the circumferential direction, and then a specific thread pattern is detected from an inspection target image obtained by photographing the mouth, and difference processing is performed between the reference image and the inspection target image to determine whether the container is good or bad.

JP 2016-8930 A

However, the inspection method described in Patent Document 1 requires large-scale equipment, which increases capital investment, and there are also accuracy issues when applying it to dimensional measurements.

The present invention was devised in light of the above-mentioned conventional situation, and aims to provide a container inspection device and inspection method that can significantly simplify the device configuration and enable accurate dimensional measurement with simple operations.

In order to achieve the above-mentioned object, the inspection device of the present invention comprises a holder for holding a container, and a fixed part and a movable part that abut against the container, and inspects the outer diameter dimensions of the container by abutting the fixed part as a reference against the container held by the holder and abutting the movable part at a position opposite to the position where the fixed part is abutted, and measuring the distance between the fixed part and the movable part with a displacement meter, characterized in that the holder is attached and fixed to a fixed stage, the fixed stage is a rotating device, and the fixed part is movable relative to the holder.

In addition, the inspection method of the present invention is an inspection method for inspecting the outer diameter dimension of a container by abutting a reference fixed part against a container held by a holder, abutting a movable part at a position opposite to the position where the fixed part is abutted, and measuring the distance between the fixed part and the movable part with a displacement meter, wherein the holder is attached and fixed to a fixed stage, the fixed stage is a rotating device, and the fixed part is movable relative to the holder.

The inspection device and inspection method of the present invention basically only require a fixed part and a movable part to be brought into contact with a container held by a holder, and the device structure is very simple.

However, when the fixed part is integrated with the holder, if the position of the center of the threaded part formed on the mouth of the container shifts (especially if it shifts toward the movable part), the measured value will deviate from the actual dimensions of the threaded part. The center of the threaded part is positioned by the holder that holds the container, but the mounting position of the holder can shift when the holder is attached and detached, which can result in the center of the threaded part shifting.

In the inspection device and inspection method of the present invention, the fixed part is movable relative to the holder, so that even if the mounting position of the holder is misaligned, the fixed part can be moved to correct this, achieving stable and accurate measurements.

The inspection device and inspection method of the present invention can greatly simplify the device configuration and enable highly accurate dimensional measurement with simple operations.

FIG. 2 is a plan view showing a schematic configuration of a sealing device including an inspection process and a sealing process. FIG. 11 is a schematic plan view illustrating an inspection process. 1 is a schematic side view showing a configuration of an inspection device in which a fixing part is movable relative to a holder.

Below, an embodiment of an inspection device and an inspection method to which the present invention is applied will be described with reference to the drawings.

Figure 1 shows an example of a sealing device incorporating the inspection device of the present invention. In this sealing device, the height of the thread formed on the mouth of a container is inspected, and then a seal is applied to the container.

The sealing device shown in Figure 1 is a rotary device, and the container 1 is held by a holder 2 attached and fixed to a turntable, which is a fixed stage, and is transferred to the inspection process and the sealing process. In other words, the container 1 loading section A, thread inspection section B, sealing process section C, and unloading section D are arranged at equal angular intervals (90° intervals) on a circular transport path, and are designed to carry out a series of processes.

The target container 1 is, for example, a blow-molded container formed by blow molding. When forming a blow-molded container, a cylindrical molten resin (parison) is sandwiched between dies and air is blown into the interior to make it adhere to the die cavity and give it the desired container shape. At this time, a screw thread is formed on the mouth portion 1A.

The container 1 molded by the blow molding process is first carried into the loading section A, and the body is held by the holder 2. The holder 2 is a combination of a pair of L-shaped jigs that sandwich and grip the body of the container 1. In this embodiment, the container 1 is held by the holder 2 in an inverted state (with the mouth 1A facing downwards).

Next, the turntable rotates 90°, and the container 1 held in the holder 2 is transferred to the thread inspection section B. In the thread inspection section B, the height of the thread formed on the mouth 1A of the container 1 is inspected to confirm that it is within the specified height tolerance.

Containers 1 whose thread height has been confirmed to be within the allowable range in thread inspection section B are then transferred to sealing process section C by a further 90° rotation of the turntable. In sealing process section C, a seal is applied using a sealing machine. A predetermined seal (such as a seal indicating the contents or a seal indicating the quality) is applied to the container 1 depending on the contents, etc.

The container 1 with the sticker attached is then transported to the discharge section D by rotating the turntable by 90 degrees, and is then removed from there.

Next, we will explain an embodiment of the inspection device and inspection method for the thread inspection process.

As shown in Figures 2 and 3, the thread inspection device and thread inspection method of this embodiment sandwich the mouth 1A of a container 1 between a fixed part 11 and a movable part 12 to inspect the height of the thread 1B formed on the mouth 1A. The fixed part 11 and the movable part 12 are cylindrical jigs each having a predetermined thickness, and these cylindrical fixed part 11 and movable part 12 abut against the mouth 1A of the container 1 while being supported by a support shaft 13 or a support shaft 14.

When the fixed part 11 and the movable part 12 are abutted against the mouth part 1A on which the thread 1B is formed, the fixed part 11 and the movable part 12 come into contact with the top of the thread 1B, and the maximum diameter (outer diameter dimension at the top) d of the thread 1B is measured by measuring the distance between the fixed part 11 and the movable part 12 with the displacement meter 21. The maximum diameter of the thread 1B corresponds to the height of the thread 1B, and the height of the thread 1B is inspected by the above measurement.

When inspecting the thread 1B, the fixed part 11 is a jig that serves as a reference for measurement, and is attached to the fixed stage 31 to which the holder 2 that holds the container 1 is fixed, so that the fixed part 11 does not move relative to the holder 2. However, the attachment position may shift when attaching or detaching during so-called changeover work, which may reduce the measurement accuracy.

When measuring the outer diameter by clamping the mouth 1A (thread 1B) between the fixed part 11 and the movable part 12, the center of the mouth 1A needs to be located on the center line connecting the center of the circular fixed part 11 and the center of the circular movable part 12. If the center of the mouth 1A deviates from the center line, the maximum diameter cannot be measured accurately. If the mounting position of the holder 2 is shifted, a shift will occur in the positional relationship between the holder 2 (i.e. the mouth 1A of the container 1) and the fixed part 11, making accurate measurement impossible.

Therefore, in the thread inspection device and thread inspection method of this embodiment, the fixed part 11 is made movable relative to the holder 2, and if any deviation occurs in the mounting position of the holder 2, this is corrected.

Specifically, as shown in FIG. 3, the fixed part 11 is not fixed to the fixed stage 31 to which the holder 2 is attached, but is fixed to the first support stage 32 which is movable relative to the fixed stage 31. Here, the first support stage 32 is connected to the fixed stage 31 via a linear guide and is capable of linear relative movement along the linear guide. The linear guide is composed of a rail 41 and a moving block 42 which moves along the rail 41, the lower surface of the rail 41 is fixed to the upper surface of the fixed stage 30, and the upper surface of the moving block 42 is fixed to the lower surface of the first support stage 32. When the position of the holder 2 (mouth 1A of the container 1) attached to the fixed stage 31 is shifted, the first support stage 32 moves relative to the fixed stage 31 by moving the moving block 42 along the rail 41, and the fixed part 11 can be aligned with respect to the holder 2 (mouth 1A of the container 1), and the position shift is corrected.

On the other hand, the movable part 12 is attached to a second support stage 33 separate from the fixed part 11, and can move relative to the fixed part 11. That is, the second support stage 33 is connected to the first support stage 32 via a linear guide, and the lower surface of the rail 41 of the linear guide is fixed to the upper surface of the first support stage 32, and the upper surface of the moving block 42 is fixed to the lower surface of the second support stage 33. By moving the moving block 42 along the rail 41 and moving the second support stage 33 relative to the first support stage 32, the movable part 12 is moved to sandwich the threaded part 1B of the container 1 between the fixed part 11, and the amount of displacement of the movable part 12 when sandwiched is measured by the displacement meter 21, whereby the outer diameter (height) of the thread 1B is measured.

At this time, the movable part 12 must move on the line (the center line) connecting the center of the fixed part 11 and the center of the mouth part 1A of the container 1, and clamp the container 1 so that the center of the mouth part 1A is positioned on the center line connecting the center of the fixed part 11 and the center of the movable part 12. The linear guide between the fixed stage 31 and the first support stage 32 and the linear guide between the first support stage 32 and the second support stage 33 are installed coaxially so that the movable axis (rail 41) coincides with the center line.

A displacement gauge 21 is also provided to measure the amount of displacement of the movable part 12. The displacement gauge 21 is provided on the first support stage 32 to which the fixed part 11 is attached, and is attached so that the tip of the measurement gauge abuts against the second support stage 33 to which the movable part 12 is attached. The measurement gauge of the displacement gauge 21 is biased by a spring force in a direction to abut against the second support stage 33, and the amount of movement of the second stage 33 is measured based on the change in the amount of protrusion. By measuring the amount of movement of the second support stage 33, the amount of displacement of the movable part 12 is measured, and the distance between the movable part 12 and the fixed part 11 (the outer diameter at the thread 1B of the container 1) is measured.

The inspection method using the thread inspection device configured as above will be explained. When the container 1 held in the holder 2 is transferred to the thread inspection section B, the position of the first support stage 31 (fixed section 11) is first adjusted by the linear guide to correct any positional deviation relative to the holder 2, and then the first support stage 31 (fixed section 11) is brought into contact with the thread 1B of the container 1 held in the holder 2.

Next, the linear guide (linear guide between the first support stage 31 and the second support stage 32) to which the movable part 12 is attached is operated to move the movable part 12 along the line connecting the fixed part 11 and the center of the mouth part 1A of the container 1, and abuts it against the thread 1B of the container 1 held by the holder 2.

At this time, the displacement of the movable part 12 is measured by the displacement meter 21, and the outer diameter dimension of the thread 1B of the container 1 is measured. Then, based on the measurement results, if it is within the tolerance range of the reference value, it is judged to be a good product, and if it is outside the tolerance range, it is judged to be a defective product.

As mentioned above, the thread inspection device and inspection method of this embodiment have a simple device configuration, and even if the holder 2 is misaligned when it is attached, it is possible to perform accurate dimensional measurements.

Although an embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

For example, in the previous embodiment, the container 1 is held in an inverted state by the holder 2, with the mouth 1A facing downwards to measure the outer diameter, but the container 1 may be held upright. When holding the container 1 upright, it is also possible to hold the mouth 1A or neck of the container 1 with the holder 2 and hold the container 1 in a hanging manner. Any holding state can be adopted depending on the position at which the outer diameter of the container 1 is to be measured.

In the previous embodiment, the method was applied to measuring the height of the threads on a container, but it can also be applied to measuring the outer diameter of the body of a container. Furthermore, the measurement of the outer diameter of the body of a container can also be applied to inspecting containers for leaks.

After the containers are blow-molded, they may be transported to the food factory in a sealed state by air hole sealing (closing the hole at the tip of the container's mouth with hot air). In such cases, a leak test is carried out to ensure that the containers are sealed.

The above-mentioned inspection device and inspection method can be applied to this leak inspection. Specifically, for example, a spring force is applied to the second support stage 33 on the movable part 12 side, and the body of the container 1 is sandwiched between the fixed part 11 and the movable part 12 with a predetermined force. The mouth part 1A of the container 1 is grasped by the holder 2 and held in a hanging state. This makes it easy to bring the fixed part 11 and the movable part 12 into contact with the body.

At this time, if the container 1 is kept airtight, the spring force will not crush the body of the container 1, and the outer diameter of the body will be maintained. If the airtightness of the container 1 is lost, the spring force will press the movable part 12 against the body of the container 1, causing the container 1 to be crushed, and the dimensions of the body will become smaller.

Then, in the same way as measuring the outer diameter of the thread, the distance between the fixed part 11 and the movable part 12 (the outer diameter dimension of the body of the container 1) is measured, and if it is a specified dimension, it is determined that the sealed state is maintained. If the measurement result is smaller than the specified dimension, it is assumed that air has escaped (it is not sealed), and it is determined that the seal is defective.

Even in the leak inspection, the inspection device has a simple configuration and can easily correct the positional deviation caused by the attachment of the holder 2, allowing for accurate dimensional measurement.

Reference Signs List 1 Container 1A Mouth 1B Screw thread 2 Holder 11 Fixed part 12 Movable part 21 Displacement meter 31 Fixed stage 32 First support stage 33 Second support stage 41 Rail 42 Moving block

Claims (7)

The container holder includes a fixed portion and a movable portion that are brought into contact with the container.
An inspection device that inspects an outer diameter dimension of a container by abutting a fixed part serving as a reference against a container held by a holder, abutting a movable part at a position opposite to the position where the fixed part is abutted, and measuring the distance between the fixed part and the movable part with a displacement meter,
The holder is attached and fixed to a fixed stage, the fixed stage being a rotating device;
The inspection device according to claim 1, wherein the fixing portion is movable relative to the holder. The inspection device according to claim 1, characterized in that the outer dimensions of the container are the outer diameter dimensions of the threads formed on the mouth of the container. The inspection device according to claim 2, characterized in that the container is held in an inverted, upside-down state in the holder. The inspection device according to claim 1, characterized in that the outer dimensions of the container are the outer diameter dimensions of the body of the container, and the inspection device performs a leak inspection of the sealed container by pinching the body of the container between the fixed part and the movable part with a predetermined force and measuring the distance between the fixed part and the movable part. An inspection device according to any one of claims 1 to 4, characterized in that the fixed part and the movable part have cylindrical parts with enlarged diameters at the ends of the support shafts, and the outer circumferential surfaces of these cylindrical parts are brought into contact with the container. the fixed portion is fixed to a first support stage, and the movable portion is fixed to a second support stage;
the first support stage is movable relative to the fixed stage by a linear motion guide, and the second support stage is movable relative to the first support stage by a linear motion guide;
the movable part moves on a line connecting the center of the fixed part and the center of the mouth of the container, and clamps the container so that the center of the mouth of the container is positioned on the center line connecting the center of the fixed part and the center of the movable part;
An inspection device as described in any one of claims 1 to 5, characterized in that the linear guide between the fixed stage and the first support stage and the linear guide between the first support stage and the second support stage are installed coaxially so that their movable axes coincide with the center line. An inspection method for inspecting an outer diameter dimension of a container by abutting a fixed part serving as a reference against a container held by a holder, abutting a movable part at a position opposite to the position where the fixed part is abutted, and measuring a distance between the fixed part and the movable part with a displacement meter, comprising:
The holder is attached and fixed to a fixed stage, the fixed stage being a rotating device;
The inspection method according to the present invention, characterized in that the fixed portion is movable relative to the holder.

Images