Information
-
Patent Grant
-
6427422
-
Patent Number
6,427,422
-
Date Filed
Thursday, July 22, 199925 years ago
-
Date Issued
Tuesday, August 6, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Gerrity; Stephen F.
- Huynh; Louis
Agents
- Beyer Weaver & Thomas LLP
-
CPC
-
US Classifications
Field of Search
US
- 053 409
- 053 436
- 053 437
- 053 451
- 053 495
- 053 501
- 053 502
- 053 503
- 700 304
- 700 305
-
International Classifications
-
Abstract
Packages are each made by clamping a tubularly formed bag-making film, dropping a batch of articles into this film while it is in this clamped condition, and shaking this batch of articles to thereby increase its volume density. This is done once or repeated any number of times. After articles of the final batch are dropped into the film, the clamped condition of the film is released and the articles are dropped further downward to the bottom of the bag being made. The tubularly formed film is thereafter sealed transversely above the articles which have been received to close the bag.
Description
BACKGROUND OF THE INVENTION
This invention relates to a method of making packages by means of a packaging machine. More particularly, this invention relates to a method of making packages by increasing the volume density of the articles that are to be packaged.
Packages of articles which are easily breakable and low in volume density, such as potato chips, are difficult to handle efficiently because a large amount of package-making material is required to package them and the costs of their transportation are high. In view of this problem, U.S. Pat. No. 5,540,035, for example, disclosed a method of shaking the articles which have been dropped into a bag before it is sealed such that the volume of the batch of articles to be sealed in is reduced. If this technology is applied to a large-scale packaging machine adapted to package twice or three times more articles in each bag than a packaging machine of a normal size, however, it is not possible to effectively increase the volume density of articles inside the bag, and the packaging speed is adversely affected significantly.
SUMMARY OF THE INVENTION
It is therefore an object of this invention in view of this problem of the prior art technology to provide an improved method of producing large packages while efficiently increasing the volume density of the articles.
A packaging method embodying this invention, with which the above and other objects can be accomplished, may be characterized as comprising the steps of clamping a tubularly formed bag-making film with a shaking mechanism (herein referred to as the shaker), dropping a batch of articles into this film while it is in this clamped condition, and shaking this batch of articles by activating the shaker to thereby increase its volume density. This is done once or repeated any number of times, and after articles of the final batch are dropped into the film, the clamped condition of the film is released and the articles are dropped further downward to the bottom of the bag being made. The tubularly formed film is thereafter sealed transversely above the batches of articles which have been dropped to close the bag.
The user may use an input device to input various packaging conditions such as the length of each bag to be made and the packaging speed (that is, the number of packages to be produced per unit time). A packaging machine according to this invention includes a control unit which determines whether the film should be transported intermittently or continuously by comparing at least one of the inputted packaging conditions and a preliminarily stored value such as a packaging speed. The steps described above are carried out if the control unit concludes that the film should be transported in an intermittent mode. If the control unit concludes that the film should be transported in a continuous mode, the film is pulled down in a continuous motion without subjected to the shaking by the shaker.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:
FIG. 1
is a schematic representation, in part as a block diagram, of a packaging machine which makes use of a method embodying this invention;
FIGS. 2A and 2B
are respectively a plan view and a side view of the shaker of the packaging machine of
FIG. 1
;
FIGS. 3A
,
3
B,
3
C,
3
D,
3
E and
3
F are schematic drawings for showing the sequence of packaging operations by the packaging machine of
FIG. 1
in an intermittent mode of film transportation;
FIG. 4
is a timing chart for the packaging operations of
FIGS. 3A
,
3
B,
3
C,
3
D,
3
E and
3
F;
FIGS. 5A
,
5
B,
5
C,
5
D and
5
E are schematic drawings for showing the sequence of packaging operations by the packaging machine of
FIG. 1
in a continuous mode of film transportation; and
FIG. 6
is a timing chart for the packaging operations of
FIGS. 5A
,
5
B,
5
C,
5
D and
5
E.
DETAILED DESCRIPTION OF THE INVENTION
The invention is described next by way of an example.
FIG. 1
shows schematically the structure of a packaging machine embodying this invention. An elongated bag-making material (the “film”)
100
is transported to a former
2
to be thereby bent into a tubular form around a tubular structure which is integrally formed with a hopper
1
, and is pulled down along this tubular structure by means of a pair of pull-down belts
31
(only one of the pair being visible in
FIG. 1
) driven by a belt-driving motor
33
controlled by a control unit
9
. The pair of pull-down belts
31
and a longitudinal sealer
32
, comprising a heater to seal together the mutually overlapping side edges of the film
100
, together form a pull-down mechanism
3
, disposed below the former
2
.
Disposed below this pull-down mechanism
3
and immediately above a transverse sealer
7
is a shaker
5
for causing the articles being dropped from a weigher (not shown) into the interior of the bag in the making, while clamping the tubularly formed film
100
in a coordinated way with the operation of the weigher such that the volume density of the articles will be increased. The transverse sealer
7
is for sealing the tubularly formed film
100
in the transverse direction and comprises a pair of seal jaws
71
and jaw-operating motors
73
and
74
controlled by a control unit
9
for causing the pair of seal jaws
71
to undergo a cyclic motion along generally D-shaped trajectories, as disclosed more in detail, for example, in U.S. Pat. No. 5,753,067. Numeral
10
indicates an input device through which a user may input “packaging conditions”, such as the length of the bags to be produced, the target weight of articles to be packaged in each bag, the packaging speed or the number of packages to be produced per unit time, on which operations of various kinds are to be carried out. direction and comprises a pair of seal jaws
71
and jaw-operating motors
73
and
74
controlled by a control unit
9
for causing the pair of seal jaws
71
to undergo a cyclic motion along generally D-shaped trajectories, as disclosed more in detail, for example, in U.S. Pat. No. 5,753,067. Numeral
10
indicates an input device through which a user may input “packaging conditions”, such as the length of the bags to be produced, the target weight of articles to be packaged in each bag, the packaging speed or the number of packages to be produced per unit time, on which operations of various kinds are to be carried out.
Explained more in detail, the shaker
5
is adapted to clamp a portion of the film
100
periodically, once every time the film
100
is pulled down by a distance equal to the length of the bags being made. In a mode of operation wherein articles with a desired total weight are dropped successively in two batches to produce a packaged bag, for example, the shaker
5
shakes the articles of the first batch which are dropped in first, thereby increasing their volume density. The shaker
5
then releases the clamping as articles of the second batch are dropped into the film
100
. As a result, the articles fill the interior of the tubularly formed film
100
at an increased volume density with the bottom of the bag sealed transversely.
FIGS. 2A and 2B
show the structure of this shaker
5
more in detail. Its main body (the “shaker main body”)
51
is in the form of a frame, surrounding the tubularly formed film
100
, and is attached to a pair of left-hand side and right-hand side frame structures
53
through a shaft
52
penetrating the shaker main body
51
in the direction of its width (the vertical direction in
FIG. 2A
) so as to be able to oscillate. At one end of the shaker main body
51
in its longitudinal direction (the horizontal direction in
FIG. 2A
) is a longitudinally extending shaft
54
which is eccentrically coupled through a connecting bar
58
with the shaft
56
of a decelerating gear
55
such that the rotary motion of a shaker motor
57
for shaking, controlled by the control unit
9
, is converted into an up-and-down motion such that the main body
51
will undergo an oscillatory motion in the vertical direction around the shaft
52
.
A pinion
61
is affixed to one end of this shaft
52
penetrating the shaker main body
51
, engaging a rack
60
which is adapted to be driven by a driver cylinder
59
, controlled by the control unit
9
, to undergo a reciprocating forward-backward motion in the longitudinal direction. A belt
64
is supported between a driver pulley
62
affixed to the shaft
52
and a follower pulley
63
on the shaker main body
51
. A pair of shutters
66
and
67
is attached to the mutually oppositely facing surfaces of this belt
64
such that these shutters
66
and
67
can be moved towards or away from each other by moving the rack
60
backward and forward to move the belt
64
.
In
FIG. 2
, numeral
68
indicates a sensor for counting the number of oscillations of the shaker main body
51
by detecting a plate
69
attached to the shaft
56
of the decelerating gear
55
. The control unit
9
serves to control the operations of the motions of the motors
33
,
57
,
73
and
74
for the pull-down belts
31
, the shaker main body
51
of the shaker
5
and the transverse sealer
7
. The timing for the control of these motors by the control unit
9
is explained next with reference to sketches in
FIGS. 3A
,
3
B,
3
C,
3
D,
3
E and
3
F, as well as the timing chart of FIG.
4
.
If the packaging speed inputted through the input device
10
is greater than a preselected specified value (“specified packaging speed”) preliminarily stored in the control unit
9
, or if articles to be packaged together to make one package are dropped together all at one as a single batch according to a selected mode of operation, the control unit
9
carries out a normal continuous mode of film transportation, transporting the film
100
in a continuous manner without shaking the articles which have been dropped in. If the inputted packaging speed through the input device
10
is less than the specified packaging speed, or if the articles with a target total weight are dropped successively in a plurality of batches according to a selected mode of operation, on the other hand, the control unit
9
advances the film
100
intermittently by a distance equal to the length of the individual bags to be made.
Let us now consider a mode of operation wherein articles having a target total weight are dropped successively in two batches, each weighing about one half of the target weight. This mode of operation is described, for example, in U.S. Pat. No. 4,508,185 and hence will not be described herein in detail. After a cycle of operations including weighing and packaging (say, at time t
a
in FIG.
4
), the seal jaws
71
of the transverse sealer
7
are stopped at specified initial positions (indicated by numeral
710
in
FIG. 1
) immediately before they contact each other, the shutters
66
and
67
of the shaker
5
are stationary while clamping the tubularly formed film
100
as shown in
FIG. 3A
, and the pull-down belts
31
are at rest. When the weigher receives a ready signal from the packaging machine under this condition, requesting a discharge of weighed articles, a batch of articles with a total weight equaling about one half of the target total weight is measured and dropped into the tubularly formed film
100
in a clamped condition, and the shaker motor
57
rotates for a specified length of time T
1
(from time t
b
in FIG.
4
), causing the shaker main body
51
to oscillate up and down around the shaft
52
so as to increase the volume density of the articles which have been dropped, as shown in FIG.
3
B. Thereafter, when a second batch of articles weighing also about one half of the target total weight (such that the sum of the weights of the first and second batches of articles equals the target total weight) is dropped from the weigher as shown in
FIG. 3C
in response to another ready signal outputted from the packaging machine and a discharge-end signal indicative of the completion of a discharge of articles is returned from the weigher at time t
c
, the motors
73
and
74
for the seal jaws
71
begin to rotate after a short wait period of T
2
. After still another period of time T
3
(at time t
d
), the seal jaws
71
engage each other immediately before the articles of the second batch reach the shaker
5
and seal the bottom edge of the bag being formed. At the same time (at time t
d
), the downward motion of the film
100
is started in synchronism with the rotary motion of the seal jaws
71
and the driver cylinder
59
is also activated so as to cause the pair of shutters
66
and
67
to move away from each other through the rack
60
, the pinion
61
engaging with the rack
60
, the driver pulley
62
which rotates with the pinion
61
, and the belt
64
stretched between the driver pulley
62
and the follower pulley
63
. As a result, the articles of the first batch of which the volume density has been increased by the shaker
5
and the articles of the second batch received subsequently are together dropped into the bag being formed with its bottom edge sealed between the seal jaws
71
, as shown in FIG.
3
D.
The film
100
is pulled down by the pull-down belts
31
at the same speed as the downward motion of the seal jaws
71
on the straight line portions of their generally D-shaped trajectories. By time t
c
, when the film
100
is pulled down by a distance equal to the length of the bag being made, the first and second batches of the articles are together completely inside and the seal jaws
71
are back at their specified initial positions
710
, as shown in FIG.
3
E. After the downward motion of the film
100
is also stopped around the same time, the shutters
66
and
67
wait for a specified period T
4
until the dropped articles settle and then clamp the film
100
above these articles. At the same time t
f
, the shaker
5
is activated again as shown in
FIG. 3F
, causing the shaker main body
51
to oscillate around the shaft
52
up and down so as to increase the volume density of not only the articles of the second batch already inside the closed bag but also the next batch of articles dropped in the meantime for the next bag to be produced. Thus, a space is created above the enclosed articles for transversely sealing the film
100
with the seal jaws
71
, and the sequence of steps described above is repeated thereafter.
Let us consider next a situation wherein the film
100
is pulled down in a continuous manner and articles having a target total weight are dropped in together as a single batch. In this mode of operation, the shutters
66
and
67
remain open and the shaker
5
is kept inactive.
FIG. 5A
shows a situation at time t′
a
as shown in
FIG. 6
prior to the output of a ready signal. If a ready signal is outputted from the packaging machine (at time t′
b
in
FIG. 6
) under this condition and the weigher discharges weighed articles in a single batch and outputs a discharge-end signal (at time t′
c
in FIG.
6
), the control unit
9
causes the jaw-operating motors
73
and
74
to start moving the seal jaws
71
and the belt-driving motor
33
to start pulling down the film
100
after waiting for a predetermined period of time T
2
(at time t′
d
) as shown in
FIGS. 5B and 5C
such that the seal jaws
71
close the bag in time to receive the article batch thereabove, as shown in FIG.
5
D. Thereafter, the seal jaws
71
continue to rotate and the film
100
continues to move down as shown in
FIG. 5E
, and the seal jaws
71
transversely seal the film
100
to form simultaneously the top seal of the bag which has just been filled and the bottom seal of the bag to be filled in the next cycle of operation. If the next ready signal is thereafter outputted from the packaging machine (at time t′
e
) and a discharge-end signal is received from the weigher in response, the pull-down belts
31
is continuously rotated and the seal jaws
71
are caused to undergo another cycle of rotary motion at the same time, as described above. If no discharge is made and no discharge-end signal is accordingly outputted from the weigher, for whatever reason, as indicated by a dotted line at time t′
f
in
FIG. 6
, the control unit
9
causes the seal jaws
71
to complete the transverse sealing to thereby close the top end of the bag which has just been filled in the previous cycle of operation and to return to, and to rest at, their specified initial positions
710
, stopping the pull-down belts
31
after a predetermined period of time T
5
has elapsed from the moment when a discharge-end signal was normally to be received, as shown in FIG.
6
.
Although the invention has been described above for a mode of operation wherein articles with a target total weight are dropped in two batches to make each package, the articles of the first batch being shaken after being dropped such that their volume density is increased before the articles of the second batch are dropped, this is not intended to limit the scope of the invention. In general, articles with a target total weight may be dropped consecutively in n batches where n may be any integer equal to or greater than 2, and the bag may be shaken by the shaker after articles of each of the first (n−1) batches have been dropped. Articles of all n batches are added together to form one package only after the articles of the n
th
batch (the “final batch”) are dropped.
Thus, the bag is shaken after each time articles of one of the first (n−1) batches are dropped such that their volume density is increased, and the bag is finally sealed and shut after the final batch of articles is dropped in. In this manner, packages with a smaller volume can be produced according to this invention such that their costs of production as well as of transportation can be significantly reduced. Since this operation for increasing the volume density of the articles is carried out simultaneously with the transverse sealing of the film, the packaging speed is not adversely affected. In a mode of operation wherein the tubularly formed film is transported intermittently, furthermore, the speed of film transportation can be increased to thereby increase the distance along which the film is stroked such that the so-called browsing effect can be enhanced.
The disclosure given above is intended to be interpreted broadly. It goes without saying that the packaging machine of this invention can be operated not only with a weigher adapted to drop in article batches according to their weights but also with a device adapted to supply article batches according to their volumes or number of individual articles.
Claims
- 1. A packaging method comprising the steps of:clamping a tubularly formed film transversely at a clamping position with a shaker to prevent articles from passing across said clamping position; dropping batches of said articles sequentially into said film from above said clamping position while said film is in a clamped condition by said shaker; shaking the articles above said clamping position by means of said shaker after each of said batches has been dropped into said film to thereby increase volume density of said articles inside said tubularly formed film; releasing said film from said clamped condition to thereby further drop the shaken articles past said clamping position after articles of a final batch are dropped into said film; and thereafter sealing said tubularly formed film transversely above the dropped articles.
- 2. The packaging method of claim 1 further comprising the steps of preliminarily specifying a reference packaging speed and inputting a target packaging speed at which packages of said articles are produced by said packaging method; and comparing said target packaging speed with said reference packaging speed by means of a control unit so that the steps of claim 1 are carried out and said film is transported intermittently each time by a specified bag length if said target packaging speed is less than said reference packaging speed, and that said film is transported continuously and said shaker is inactive if said target packaging speed is greater than said reference packaging speed.
- 3. The packaging method of claim 1 further comprising the steps of:preliminarily storing a reference value; inputting packaging conditions for producing packages through an input device; comparing said reference value with said packaging conditions by means of a control unit and thereby selecting a mode of operation from the group consisting of continuous mode and intermittent mode; transporting said film intermittently each time by a bag length according to said packaging conditions and carrying out the steps of claim 1 if said intermittent mode has been selected; and transporting said film continuously while keeping said shaker inactive if said continuous mode has been selected.
- 4. The packaging method of claim 1 wherein said shaker shakes said film in an up-and-down motion.
- 5. A packaging method comprising the steps of:intermittently transporting a tubularly formed film; clamping said tubularly formed film transversely at a clamping position with a shaker to prevent articles from passing across said clamping position; dropping a first batch of said articles which is about one half of a predetermined target total quantity into the clamped tubularly formed film from above said clamping position; shaking said first batch of articles above said clamping position by means of said shaker; thereafter dropping a second batch of articles from above said clamping position into said tubularly formed film, releasing said clamped tubularly formed film and thereby allowing said first batch and said second batch of articles to drop past said clamping position and transversely sealing said tubularly formed film below said clamping position to form a bottom of a bag, said first batch and said second batch of articles together being of said target total quantity; thereafter stopping the transportation of said tubularly formed film; thereafter similarly clamping said tubularly formed film with said shaker at a next clamping position on said film; thereafter dropping another first batch of articles from above said next clamping position into the clamped tubularly formed film; and thereafter shaking simultaneously both said another first batch of articles above said next clamping position and said first batch and said second batch of articles below said next clamping position on said tubularly formed film.
- 6. The packaging method of claim 5 wherein said tubularly formed film is transported along a film path and said shaker is disposed on said film path.
- 7. The packaging method of claim 5 wherein said shaker shakes said film in an up-and-down motion.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-207977 |
Jul 1998 |
JP |
|
US Referenced Citations (8)
Foreign Referenced Citations (3)
Number |
Date |
Country |
1278562 |
Jan 1970 |
GB |
WO 9413537 |
Jun 1994 |
WO |
WO 9702179 |
Jan 1997 |
WO |