JP3191246B2 - Automatic inspection machine for uneven thickness of plastic molded containers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic container such as a cup-shaped container, a bottle-shaped container, and the like, which are formed by plastic forming such as sheet forming by vacuum, pressure forming or blow molding using a plastic sheet. The present invention relates to an automatic thickness deviation inspection device for plastic molded containers for inspecting the presence or absence of thickness deviation occurring on the outer wall of a container.

[0002]

2. Description of the Related Art Generally, in a plastic container, it is desirable that the thickness (thickness) distribution of the wall surface of the container is ideally uniform according to a predetermined container design. However, the thickness of the plastic wall of the molded container is slightly uneven due to the influence of molding conditions and the like, and the thickness of the plastic container molded by the sheet molding, the blow molding method or the like is slightly uneven.
Is caused.

[0003]

As a conventional method for measuring the above-mentioned uneven thickness, there is a contact type or non-contact type thickness inspecting machine. There is a problem that a scratch is easily generated and the speed of the inspection is limited, and the non-contact type light transmission type thick inspection device cannot be used when the container to be inspected is opaque. The present invention
An object of the present invention is to enable high-speed inspection of the presence or absence of uneven thickness of a molded wall surface of a plastic container regardless of whether it is transparent or opaque.

[0004]

According to the present invention, there is provided a rotating table 3 which is capable of mounting and fixing a plastic-inspected container 1 to be inspected at an opening 1a thereof and which is rotatable. Turntable 3 for suctioning the inside of container 1 to be inspected under negative pressure
And a non-contact type displacement sensor 4 which is provided at an appropriate position along the outer wall surface of the container 1 to be inspected mounted and fixed on the turntable 3. This is an automatic inspection machine for uneven thickness of plastic molded containers.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic inspection apparatus for uneven thickness of a plastic molded container according to the present invention will be described in detail below in accordance with embodiments. FIG. 1 is a perspective view showing an embodiment of an automatic thickness deviation inspection apparatus for plastic molded containers according to the present invention, which is supported by a vertical rotation shaft rotatably supported by an inspection apparatus main body frame 10 (support portion). A rotatable table 3 is provided on which the container 1 to be inspected obtained by plastic molding such as a cup or a bottle can be fixed on its upper surface by mounting the opening 1a side thereof. It has become.

[0006] The container 1 to be inspected (container to be inspected) is attached and fixed to the turntable 3 so that, for example, a portion corresponding to the center axis of the cylindrical container 1 coincides with the rotation center of the turntable 3. .

An air suction hole 3a for sucking air from the air suction flow path 5 is provided on the surface of the turntable 3, and the opening 1a of the container 1 is brought into contact with the turntable 3 so that the air suction hole 3a When the air is further sucked, the inside of the container 1 is brought into a negative pressure state.

By holding the inside of the container 1 in a negative pressure state by air suction, the container 1 is suction-fixed to the surface of the turntable 3 so that the container 1 does not move from the center of rotation due to the rotational movement of the turntable 3. To

In order to prevent the container 1 to be inspected from shifting and moving due to the rotating operation of the turntable 3, the container 1 is moved to the turntable 3.
There is provided a fixing jig 2 for fixing on the upper side.

For example, a fixing jig 2 (see FIG. 1) composed of a stepped surface closely fitted to the inner periphery of the opening 1a of the container 1 and fitted into the opening 1a is provided on the turntable 3 surface. Prepare,
A fixing jig (not shown) may be provided in close contact with the outer periphery of the opening 1a of the container 1 so as to surround the opening 1a.

The fixing jig 2 may be provided integrally with the turntable 3 or may be provided as an attachment which can be attached and detached.

The surface of the turntable 3 has a flat surface capable of sealing the inside of the container 1 by making flat contact with the peripheral edge of the opening 1a of the container 1 and, if necessary, the surface of the turntable 3 is flat and Can be finished with a relatively elastic rubber material. The fixing jig 2 composed of the stepped surface shown in FIG. 1 can be made of an elastic rubber material.

One or a plurality of laser beams emitted from one or a plurality of laser systems are opposed to each other along the outer wall (the outer peripheral portion or the bottom portion of the cylindrical container 1) of the container 1 to be inspected mounted and fixed to the turntable 3. The reflection-type displacement sensor 4 including the section and the laser receiving section is set in a fixed state.

FIG. 2 is a side view of an embodiment of an automatic thickness deviation inspection apparatus for plastic molded containers according to the present invention.
The rotating shaft 12 is integrally attached to an upper end of a rotating shaft 12 which is vertically supported by a bearing portion 11 of an inspection machine main body supporting frame 10, and a lower shaft driving gear 13 is provided at a lower end of the rotating shaft 12. The shaft drive gear 13 meshes with a drive gear 14 that is rotated by an electric motor M (servo motor, pulse motor, or the like) and is driven to rotate at a speed of, for example, 10 rpm to 100 rpm or more. Reference numeral 11b denotes a bearing portion of the support shaft 12.

Each time the support shaft 12 makes one rotation, a displacement sensor 4 such as a rotary encoder or a cam switch attached to the rotation support shaft 12 is mounted on the rotation support shaft 12. And a reset signal for resetting the detection signal for one rotation (3 rotations).
60 °) (for example, a rotation angle of 1
A timing signal decoder 16 for generating a detection gate signal (detection reading start pulse) for detecting the displacement sensor 4 is provided at every 360 ° / n such as every ° to 5 °, where n is a divisor of 360 °. .

An air suction hole 3 formed in the rotary table 3 via a fixing jig 2 is provided in a rotary support shaft 5 which supports the rotary table 3.
a air flow path 5 communicating with the air flow path a.
The air flow path 11 a in the bearing 11 communicates with the air flow path 11 a, and the air flow path 11 a communicates with the air suction pipe 15. The air is suctioned from the air suction hole 3a by suctioning air from the air suction pipe 15 at a predetermined suction pressure by a predetermined vacuum pump (not shown).

A displacement sensor 4 of a laser type, which is installed so as to be spaced apart and opposed along the outer wall of the container 1 to be inspected which is mounted and fixed in accordance with the rotation center of the turntable 3, has an upper part, a lower part, Alternatively, the container 1 is installed at a plurality of places (four places in FIG. 2), and a plurality of places (3 in FIG.
Location).

While rotating the container 1 to be inspected, the displacement state of the outer wall surface of the container 1 is detected by the displacement sensor 4, and for example, a thin portion having a specified thickness (design value) or less on the outer wall of the container 1 to be inspected. In some cases, a depression 1b is generated at the thin portion due to the negative pressure.

With respect to the separation distance between the outer wall surface of the container 1 and the displacement sensor 4 in the specified thickness portion (specified distance of zero displacement),
The distance between the outer wall surface of the container 1 and the displacement sensor 4 in the recessed portion 1b increases, and accordingly, the light is projected from the light emitting portion of the displacement sensor 4 to the outer wall surface of the container 1 and then reflected by the outer wall surface of the container 1. The incident angle of the laser beam incident on the laser light receiving unit via the optical lens changes, the laser irradiation position on the light receiving surface of the laser light receiving unit is displaced, and a CCD sensor (line sensor) equipped with the displaced position on the light receiving surface ) Can be detected as a digital signal, and the presence or absence of displacement of the outer wall surface of the container 1 can be detected.

The inspection operation of the plastic molded container uneven thickness automatic inspection machine of the present invention will be described below with reference to FIG.
A rubber fixing jig composed of a step surface integral with the turntable 3 in an opening 1a of the cylindrical container 1 (plastic bottle container) with the opening 1a of the container 1 facing downward. 2 is tightly fitted (tight), and the container 1 to be inspected is mounted and fixed on the turntable 3.

Thereafter, the air suction operation is disabled (a state in which no negative pressure is applied to the container 1 to be inspected), and the air suction operation is performed for each detection gate signal (every predetermined rotation phase angle) transmitted from the timing decoder 16 such as a rotary encoder. Then, the displacement sensor 4 starts detecting the displacement amount of the container 1 to be inspected during one rotation without applying a negative pressure. The displacement amount detection signal is temporarily stored in the data memory means as detection data (or detection signal waveform data).

Next, while rotating the rotating table 3 to rotate the container 1 to be inspected, air suction operation is performed to suck air from the air suction holes 3a, and the inside of the container of the container 1 to be inspected is adjusted to an appropriate negative pressure. After the state, by the displacement sensor 4,
The detection of the displacement amount during one rotation of the outer wall surface of the container 1 in the negative pressure state is started.

The amount of displacement detected during one rotation of the container 1 under negative pressure is determined by a timing signal decoder 16.
Each time a detection gate signal is transmitted from the sensor, it is detected by the displacement sensor 4 and the detection signal is temporarily stored in a memory means as detection data (or detection signal waveform data).

Subsequently, the displacement amount detection data in a state where no negative pressure is applied and the displacement amount detection data in a negative pressure state stored for each of the detection gate signals are sequentially read out, and the difference between them is calculated.

Further, it is possible to calculate the difference simultaneously with the detection of the displacement of the outer wall of the container 1 to be inspected in the negative pressure state. For example, the data memory means which stores the detection data in the state where no negative pressure is applied is stored. Using the detection gate signal used in the inspection of the negative pressure state as a memory read command signal, the previous detection data (memory data) in a state where no negative pressure is applied is read, and the read detection in a state where no negative pressure is applied It is possible to calculate the difference between the data and the detection data in the negative pressure state detected every time the detection gate signal is transmitted, every time the detection gate signal is transmitted.

In each of the above-described inspection methods, the outer wall of the container 1 to be inspected without applying a negative pressure is based on a detection gate signal transmitted at each predetermined rotation phase angle during one rotation of the container 1 to inspect. , And the displacement of the outer wall of the container under inspection 1 in a negative pressure state, and the displacement detection signals (detection data) of both the displacements detected at each rotation phase angle during one rotation
Is compared for each rotation phase angle to calculate the difference.

As another embodiment of the present invention, for example, based on a detection gate signal transmitted at every predetermined rotation phase angle during one rotation of the container 1 to be inspected, the inspection container 1 in a state where no negative pressure is applied. The displacement amount of the outer wall of the inspection container 1 and the displacement amount of the outer wall of the container 1 to be inspected in the negative pressure state are detected, and the respective displacement amount detection signals detected at each rotation phase angle during one rotation The maximum value and the minimum value of (detection data) are extracted, the difference between the maximum value and the minimum value of each of them is obtained as a displacement difference, and the difference between the two is calculated.

In the present invention, the container 1 to be inspected in a state where no negative pressure is applied before the air suction operation described in the above-described one embodiment and another embodiment, and the container 1 in the negative pressure state after the air suction operation is applied. The difference between the detected data and the test container 1 is used as a numerical value for test determination.

For example, when the numerical value of the difference is 0 or within a certain set range, it is determined that there is no uneven thickness in the container 1 to be inspected, while the numerical value of the difference is outside the certain set range. Is determined, the container 1 to be inspected is determined to have uneven thickness.

In the automatic inspection machine for uneven thickness of a plastic molded container according to the present invention, one or a plurality of displacement sensors 4 are installed along the outer wall surface of the container 1 to be inspected so as to face each other. 4, the difference obtained by detecting the displacement amount of the outer wall of the container 1 is obtained independently by each displacement sensor 4, and the numerical value of the difference obtained by any one of the displacement sensors 4 of all the displacement sensors 4 is 0 or When it is within a certain set range, it is determined that there is no unevenness in the container 1 to be inspected. On the other hand, when the numerical value of the difference is out of the certain set range, there is unevenness in the container 1 to be inspected. It is determined that there is.

Further, the proper value of the negative air suction pressure in the present invention is such that the concave deformation due to the negative pressure is caused only in the thin wall thickness uneven portion (portion where the outer wall thickness of the container 1 is thin) on the outer wall surface of the container 1 to be inspected. This is performed by setting an appropriate suction negative pressure to such an extent that the (concave portion 1b) is generated, and it is necessary to set so as not to deform the entire container 1 to be inspected due to excessive suction.

In the present invention, the rotation of the turntable 3 may be a rotation in a horizontal plane or a rotation in a vertical plane. The present invention is not limited to the above embodiment, and can be appropriately changed without departing from the spirit of the present invention.

[0033]

According to the present invention, there is provided an automatic inspection apparatus for uneven thickness of a plastic molded container. The container 1 can be rotated by driving the turntable 3 while sucking the negative pressure.

Further, a displacement sensor 4 is provided opposite to the outer wall of the rotating container 1 so as to be spaced apart from the outer wall of the container 1. If the outer wall of the container 1 has a thin portion due to uneven thickness, a concave portion due to negative pressure is generated on the outer wall of the container 1. The displacement occurs on the outer wall, and the distance between the outer wall of the container 1 and the displacement sensor 4 changes.
Thus, the presence or absence of uneven thickness of the container 1 to be inspected can be inspected.

[0035]

According to the present invention, there is provided an automatic inspection apparatus for uneven thickness of a plastic molded container, regardless of whether the plastic inspected container formed by plastic molding is transparent or opaque, and whether the inspected container is a perfect circle or an ellipse. In addition, there is an effect that the presence or absence of uneven wall thickness (uneven thickness of the molded wall surface) on the container molding wall surface can be accurately inspected.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of one embodiment of a thickness unevenness inspection apparatus for a plastic molded container according to the present invention.

FIG. 2 is a side view of one embodiment of the plastic molded container thickness unevenness inspection apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Container to be inspected 1a ... Opening 1b ... Concave part 2 ... Fixing jig 3 ... Rotary table 3a ... Air suction hole 4 ... Displacement sensor 5 ... Air flow path 10 ... Inspection machine main body support frame 11 ... Bearing 11a
... Air flow path 11b ... Bearing bearing part 12 ... Rotary support shaft 13 ... Rotation drive gear 14 ... Drive gear 15 ... Air flow path 16 ... Timing signal decoder M ... Electric motor

Claims (1)

(57) [Claims] 1. A turntable 3 which is mounted and fixed on a plastic molded container 1 to be inspected at an opening 1a thereof and is rotatable.
And an air suction hole 3a provided in the turntable 3 for suctioning the inside of the container 1 to be inspected attached to the turntable 3 under a negative pressure.
And a non-contact type displacement sensor 4 which is provided at an appropriate position along the outer wall surface of the container 1 to be mounted and fixed on the turntable 3 so as to face each other. Automatic inspection machine.