JPH11278435A - Method and apparatus for vacuum package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand a vacuum work time in pressure chambers housing products to be packaged and improve the efficiency of a rotary vacuum packaging machine. SOLUTION: A conventional rotary vacuum packaging machine has such a structure that pressure chambers are connected respectively to eight open holes 23 defined in a movable plate 22 and that, by rotating (30) the movable plate 22 clockwise to allow each open hole 23 to communicate with a vacuum port 16 formed in a fixed plate 12, vacuum works successively in each pressure chamber. In this rotary vacuum packaging machine, a normally closed on-off valve 33 is newly provided in a bypass pipeline 32 for connecting an auxiliary port 31 ahead of the vacuum port 16 to a vacuum pump 15, and the on-off valve 33 is temporarily opened when each open hole 23 overlaps with the auxiliary port 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

2. Description of the Related Art In a rotary vacuum packaging apparatus, as shown in FIG. 9, a plurality of pressure-resistant chambers 1 and 2 circulate on an endless track 3 at equal intervals, and an opening 4 of a pressure-resistant chamber 1 is provided with a valve 6.
The vacuum is applied to the bagged items stored in the pressure-resistant chamber 1 only while communicating with the vacuum port 7. In the drawing, the valve 6 is shown in a linearly expanded manner, but the valve 6 is a circular rotary type, and when the opening hole 4 of the front chamber 1 comes off from the vacuum port 7 to improve efficiency. The opening 5 of the rear chamber 2 is immediately connected to the vacuum port 7.

[0002]

As described above, since the rotary vacuum packaging apparatus has a structure in which each pressure chamber is isolated to generate a vacuum, as described above, in order to increase the mass production efficiency, the pressure chambers 1 and 2 in the endless track 3 are temporarily increased. When the number of 2... Is increased, the length of the vacuum port 7 must be reduced as the number of pressure-resistant chambers increases, and the vacuum operation time of the pressure-resistant chamber becomes short accordingly. As a result, efficiency cannot be improved beyond a certain limit unless the entire apparatus is enlarged. Therefore, the present invention is designed to increase the efficiency without increasing the size of the device.

[0003]

In order to achieve the above object, the present invention provides a normally closed auxiliary port in front of a vacuum port in the direction of travel of the pressure-resistant chamber, and uses the auxiliary port to provide a normally closed auxiliary port. Preliminary vacuum action is performed on the pressure-resistant chambers, and the vacuum operation time (vacuum volume) in each pressure-resistant chamber is expanded without reducing the traveling speed.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a vacuum packaging method according to the present invention, a normally closed auxiliary port is formed in front of a vacuum port in a fixed plate of a rotary valve, and each opening of a movable plate that rotates in surface contact with the fixed plate. Each time the hole overlaps the auxiliary port, the auxiliary port is temporarily opened, and a preliminary vacuum is applied to each pressure-resistant chamber connected to each auxiliary port.
Therefore, the vacuum volume acting on each pressure-resistant chamber is increased by the amount of the preliminary vacuum.

One example of a means for normally closing the auxiliary port can be constituted by providing an on-off valve in a pipe connecting the auxiliary port and the vacuum source, and keeping the on-off valve normally closed. .

Means for temporarily opening the auxiliary port each time the opening of the movable plate overlaps with the auxiliary port is provided, for example, by providing an operating piece at the same pitch as each opening on the peripheral surface of the movable plate. Place the sensor in the passband of the piece. Since the sensor detects the operating piece and sends a signal while the operating piece passes through the installation area of the sensor,
The on-off valve is opened by the electromagnetic force by the signal for the signal transmission time.

Further, the rotation angle detector engaged with the operating shaft of the movable plate can determine the pitch of each opening hole formed in the movable plate as the operating shaft rotates. Using a detector, the timing at which the preceding opening hole deviates from the vacuum port can be detected without error, and at the same time, the on-off valve can be opened to apply a preliminary vacuum to the pressure-resistant chamber intimately connected to the subsequent opening hole.

The on-off valve is not necessarily of an electromagnetic structure, but can be implemented in a purely mechanical form. For example, a full-circle cam fixed to the operating shaft of the movable plate is provided opposite to the normally-closed on-off valve, and the intermittent pressure is applied to the knock pin at the end of the spool of the valve to switch the on-off valve. By forming the full circumference cam into a shape that matches the pitch of each opening, the on-off valve can be opened by capturing the timing at which the preceding opening comes off the vacuum port.

Immediately after the preceding opening hole comes off the vacuum port, the normally closed auxiliary port is opened, and a vacuum can be instantaneously applied to the succeeding opening hole, so that the traveling speed of the pressure-resistant chamber is not reduced. The vacuum volume for each pressure chamber can be increased, and the efficiency of mass production of vacuum packaged products can be improved. It is self-evident that the pressure-resistant chamber is provided with a sealing means for the packaging container inside, so the detailed configuration is omitted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a vacuum packaging apparatus shown in FIG. 3, a circular fixed plate 12 having a circular shape in a plan view is fixed to the upper end surface of a cylindrical central shaft 11 fixedly mounted on a machine base 10 with screws 13. A vacuum source or vacuum pump 15 connected to the lower end of the shaft via a line 14 communicates with a vacuum port 16 formed on the upper surface of the fixed plate through a hollow inside the central shaft. A circular rotor 19 is fixed to an upper end of a cylindrical main shaft 18 provided around a ball bearing 17 and a pressure-resistant chamber 21 is fixed to each end of a number of arms 20 radially protruding from the rotor. An opening 23 of a movable plate 22 rotatably disposed on the fixed plate 12 and the pressure-resistant chamber 21 are connected via a tube 24.

As shown in FIG. 1, the fixed plate 12 is indicated by a solid line, and a part of the movable plate 22 is also indicated by an imaginary line. The above-mentioned pressure-resistant chamber 21 is connected to each of the opening holes 23, and the vacuum port 16 formed in the fixed board 12 is connected to the vacuum pump 15 via the line 14 as described above.

A first operating shaft 25 and a second operating shaft 26 shown in FIG. 3 are connected via a bevel gear 27 and a pinion 28 fixed to the operating shaft is connected to a gear 29 fixed to the main shaft 18. By transmitting the driving force of the first operating shaft 25 to the main shaft 18 and the rotor 19,
The movable platen 22 connected to 1 via a tube 24 receives the moving force of the pressure-resistant chamber 21 and rotates integrally with the rotor 19. This movement means that the movable platen 22 rotates clockwise as shown by the arrow 30 in FIG.
A vacuum acts on the pressure-resistant chamber only while the gas passes over the vacuum port 16.

In FIG. 1, an oval auxiliary port 31 formed in front of the vacuum port 16 in the traveling direction of each opening hole 23.
Is connected to the main line 14 via the auxiliary pipeline 32. The on-off valve 33 provided in the pipe line 32 is of a normally closed type, and the auxiliary port 31 is normally kept closed by the on-off valve 33.

As illustrated in FIG. 2, the on-off valve 33
Keeps the closed position by the pressing force of the spring 33, and switches to the open position when the sensor 35 represented by the switch symbol is closed.

As a specific example of the sensor, a proximity switch 35 shown in FIG. 1 is known. An operation piece 36 running at the same pitch as the interval between the opening holes 23 is provided with a proximity switch 35.
The proximity switch 35 is closed and the on-off valve 33 is opened only during the passage through the area. In this case, each operating piece 36
Is fixed to the peripheral surface of the movable platen 22. As other types of sensors, various image-type sensors such as a photoelectric type and a touch type are known.

Referring to FIG. 2, the movable platen 22 moves in the direction of arrow 30 on the upper surface of the fixed platen 12, and the front opening hole 23A comes off the vacuum port 16, and at the same time, the on-off valve 33 switches to the open position. Then, vacuum acts on the rear opening hole 23B overlapping the auxiliary port 31. The positional relationship between the holes is as shown in FIG. 4, and the auxiliary port 31 is kept open even in the positional relationship as shown in FIG. 5, and when the opening hole 23B is completely moved to the area of the vacuum port 16 as shown in FIG. The auxiliary port 31 is closed.

In view of the concept of the preliminary vacuum, Japanese Patent Application No. Sho 62
-182014 is known. As shown in FIG. 10, the two openings 8, 9 on the upper surface of the fixed platen 6 are connected by an internal arcuate cavity W, while the four open holes rotating the upper surface of the solid platen 6 in the arrow direction. Of these, the opening holes 4 and 5 which are respectively overlapped with the gap holes 8 and 9 are communicated via the cavity W. In short, one opening hole 4
The air in the pressure-resistant chamber connected to the
Then, it is sucked into a pressure-resistant chamber connected to the vacuum chamber and preliminarily evacuated, and then the opening hole 4 communicates with the vacuum port 7 to receive the main vacuum. At this time, the packaged product in the pressure-resistant chamber of the other opening 5 has already completed the vacuum operation, and it is significant that this extra vacuum energy is used for the pressure-resistant chamber of the one opening 4. Just vacuum port 7 and gap 8
If there is not provided at least an interval X in which the opening holes 4 can be accommodated, there is a problem that the vacuum port 7 is connected to the other opening hole 5 through the one opening hole 4, and the number of the opening holes 4 is reduced as in this known example. Although it is possible with an apparatus having a small number of holes, it becomes impossible to arrange the gap holes 9 through the above-mentioned interval X in an apparatus having as many as eight pressure-resistant chambers as shown in FIG. If allowed, vacuum port 7 and gap 9 in FIG.
1 and the auxiliary port 31 shown in FIG.
After a primary pre-vacuum through the cavity W of FIG.
When a secondary pre-vacuum is applied through the auxiliary port 31, the vacuum volume is further expanded.

An encoder 39 connected to the operating shaft 26 of FIG. 3 via a chain 38 and a controller 40 for processing an input signal from the encoder form an angle detector 41.
The means processes the pulse signal transmitted from the encoder 39 to detect the rotation angle of the movable platen 22, and opens the on-off valve 33 in accordance with the movement pitch of each opening.

The on-off valve 44 shown in FIG. 7 has a purely mechanical structure, unlike the above-mentioned electromagnetic type. The full circumference cam 46 fixed to the operation shaft 45 for driving the movable plate opens the normally closed on-off valve 44 only while touching the knock pin 47 provided at the end of the valve spool. In some cases, a crank mechanism can be operated by the operating shaft 45, and the on-off valve 44 can be opened by the crank mechanism. However, since the present invention is not an on-off valve itself, further description is omitted.

Since the failure rate of the on-off valve 44 rises in accordance with the switching frequency, as shown in FIG.
One alternative is to alternately use the four.

[Brief description of the drawings]

FIG. 1 is a plan view

FIG. 2 is a sectional view

FIG. 3 is a side view of the entire apparatus.

FIG. 4 is a diagram showing a positional relationship between a vacuum port and each opening hole.

FIG. 5 is a diagram showing a positional relationship between a vacuum port and each opening hole.

FIG. 6 is a diagram showing a positional relationship between a vacuum port and each opening hole.

FIG. 7 is an explanatory view of an on-off valve.

FIG. 8 is an explanatory diagram of an auxiliary pipeline.

FIG. 9 is an explanatory view of a conventional example.

FIG. 10 is an explanatory view of a conventional example.

[Explanation of symbols]

12 ... fixed plate 15 ... vacuum source 16 ... vacuum port 21 ... pressure-resistant chamber 22 ... movable plate 23 ... opening hole 31 ... auxiliary port 33 (44) ... opening and closing valve (normally closing means) 35 ... ‥ Sensor 41… ‥
Rotation angle detector 45… ‥ Working shaft 46… ‥ Full circumference cam

Claims (6)

[Claims] 1. A movable plate having a large number of opening holes arranged in a circle at equal intervals is rotated in contact with a surface of a fixed plate, and the opening holes are communicated at regular intervals to a vacuum port formed in the fixed plate. A packing means for applying a vacuum to a package in each pressure-resistant chamber connected to each of the opening holes, wherein a normally-closed auxiliary port formed in front of the vacuum port in the direction of travel of the opening hole; Is temporarily opened each time the opening holes overlap. 2. A movable plate having a large number of opening holes formed in a circular array at regular intervals, a pressure-resistant chamber connected to each of the opening holes of the movable plate, and a part of a contact surface with the movable plate. A fixed plate having a vacuum port connected to a vacuum source, and the movable plate is integrally rotated with each pressure-resistant chamber at a contact surface with the fixed plate, and each pressure-resistant chamber is connected to the vacuum port at a predetermined interval through each opening hole. An auxiliary port formed in front of the vacuum port of the fixed plate in the direction of travel of the opening hole, and a normal interposed in an auxiliary conduit connecting the auxiliary port and the vacuum source. A vacuum packaging apparatus comprising: a closing on-off valve; and means for temporarily opening the on-off valve each time the opening holes overlap the auxiliary port at a constant interval. 3. An auxiliary port and a vacuum source are connected by a plurality of parallel auxiliary pipelines, and each of the auxiliary pipelines is provided with a normally-closed on-off valve. 3. The vacuum packaging apparatus according to claim 2, further comprising means for alternately switching the plurality of on-off valves to temporarily open each time the valve overlaps at a predetermined interval. 4. The means for temporarily opening the on-off valve each time each opening hole overlaps with the auxiliary port at a fixed interval is provided while each operating piece provided at the same pitch as each opening hole passes through the sensor installation area. 4. The vacuum packaging apparatus according to claim 2, wherein the on-off valve is switched to the open position only by a signal from the sensor. 5. A means for temporarily opening an on-off valve each time each opening hole overlaps with the auxiliary port at a constant interval, the movement pitch of each opening hole is determined by a rotation angle detector engaged with an operating shaft of a movable plate. 4. The vacuum packaging apparatus according to claim 2, wherein the on / off valve is switched to an open position by indexing and a constant pitch signal from the angle detector. 6. A means for temporarily opening an on-off valve each time each opening hole overlaps with an auxiliary port at a constant interval, the means for causing a rotational motion of an operating shaft of a movable plate to act on the on-off valve, and a power of the operating shaft. The vacuum packaging apparatus according to claim 2, wherein the on-off valve is switched to the open position by using (1).