Technical Field
The present invention relates to a combination weigher
which feeds objects to be weighed to a packaging machine or the like.
Background Art
Objects to be weighed, such as confectionary or the like,
which are weighed by a combination weigher to have a predetermined weight, are generally
packaged by a packaging machine. A schematic construction of such a system that
weighs and packages objects to be weighed is shown in Fig. 1.
The system shown in Fig. 1 includes a packaging machine
21 disposed below a combination weigher. The combination weigher, whose operation
is entirely controlled by a control unit 10, includes a plurality of weighing hoppers
1 arranged in a circle shape, a collecting chute 3 provided below the plurality
of weighing hoppers 1, and a collecting hopper 4 provided at an outlet of the collecting
chute 3. To each weighing hopper 1, a feeding hopper (not shown) or the like disposed
thereabove feeds objects to be weighed. Furthermore, each weighing hopper 1 is attached
with a weight sensor (not shown), such as a load cell, which measures the weight
of the objects to be weighed inside the weighing hopper 1 and sends the measured
value to the control unit 10. The control unit 10 performs combination calculation
based on the measured values of the plurality of the weighing hoppers 1, determines
a combination of hoppers that will discharge the objects to be weighed, from among
the plurality of weighing hoppers 1, and opens and closes gates 2 of the weighing
hoppers 1 forming the combination, so that the objects to be weighed are discharged
from the weighing hoppers 1. The objects to be weighed discharged from the weighing
hoppers 1 slide down on the collecting chute 3, pass through the outlet provided
at the lower part of the collecting chute 3 to be temporarily accumulated in the
collecting hopper 4, and then are sent out to the packaging machine 21 when a gate
5 of the collecting hopper 4 is opened and closed under the control of the control
unit 10.
The packaging machine 21, while manufacturing bags, fills
the objects to be weighed discharged from the combination weigher in these bags
for packaging. In this packaging machine 21, a sheet of a wrapping material 27 withdrawn
from a roll 26 of the wrapping material is caused to be wound around a forming tube
23 to form a cylindrical shape, is suctioned by a pulldown belt (not shown) to be
transferred downward, and the superposed vertical edges of the cylindrically formed
wrapping material are sealed (sealing by fusion adhesion) by a vertical sealing
machine 24. Then, the objects to be weighed which have been weighed by the combination
weigher fall into a funnel 22 of the packaging machine, pass through the forming
tube 23, and are filled into a preceding bag 28. A horizontal sealing machine 25
disposed under the forming tube 23 performs a horizontal sealing (sealing by fusion
adhesion) across the upper end of the preceding bag 28 and the lower end of the
following bag. This horizontal sealing forms the preceding bag 28 into a complete
bag with its upper and lower ends sealed, because the lower end has been sealed
by the previous horizontal sealing. The horizontally sealed portion is then cut
at the center by a cutter built in the horizontal sealing machine 25 so that the
preceding bag and the following bag are separated from each other.
With regard to the above construction, a timing chart is
shown in Fig. 5, which illustrates the operation of the combination weigher and
the packaging machine in the case where the combination weigher is not provided
with the collecting hopper 4. In Fig. 5, T1 indicates a discharge cycle time of
the combination weigher, and T2 indicates a packaging cycle time that consists of
a stopping time Tc and an operating time (sealing time) Td of the horizontal sealing
machine 25 of the packaging machine 21. Since the combination weigher and the packaging
machine operate in association with each other, T1 and T2 become an equal time.
Also, Ta indicates a gate open time of the weighing hopper 1, and Tb indicates a
bag accommodating time required to accommodate from tip to tail of a bath of the
objects to be weighed discharged from the combination weigher into the bag 28 in
the packaging machine 21.
In this case, because of the absence of the collecting
hopper 4, the objects to be weighed discharged from the weighing hoppers 1 slide
down on the collecting chute 3 and fall directly from the outlet of the collecting
chute 3 into the funnel 22 of the packaging machine 21. At this time, due to the
fact that the objects to be weighed bounce back and thereby move in unwanted directions
on the collecting chute 3, or due to the unevenness in friction of objects to be
weighed with the collecting chute 3, there are variations in arrival time of the
objects to be weighed at the outlet of the collecting chute 3, thereby increasing
the length of from tip to tail of the batch of the objects to be weighed discharged
from the outlet of the collecting chute 3, and thus increasing the time taken from
the fall of the objects to be weighed until they are completely accommodated into
the bag 28. As shown in Fig. 5, the gate 2 of the weighing hopper 1 is opened during
the time Ta, and all of the objects to be weighed are discharged from the weighing
hopper 1 within this time Ta. On the other hand, the bag accommodating time Tb required
to accommodate from the tip to tail of the batch of the objects to be weighed into
the bag 28 of the packaging machine 21 is longer than the gate open time Ta of the
weighing hopper 1. With the speed up of packaging machines in recent years, if the
stopping time Tc of the horizontal sealing machine 25 is shortened, and the bag
accommodating time Tb becomes longer than the stopping time Tc of the horizontal
sealing machine 25 as shown in Fig. 5, the objects to be weighed arrive during the
operation of the horizontal sealing machine 25, so that the objects to be weighed
get stuck at the horizontal sealing machine 25. This causes not only the production
of defective packages, but also damages to the horizontal sealing machine 25.
For the above stated reason, the collecting hopper 4 is
conventionally provided so as to temporarily accumulate the objects to be weighed
discharged from the weighing hoppers 1 in the collecting hopper 4 before being discharged
into the packaging machine 21. Fig. 6 shows the timing chart, illustrating the operation
of the combination weigher and the packaging machine in that case. In Fig. 6, Te
indicates a gate open time of the collecting hopper 4, Tf indicates a gate close
time, and Tg indicates time required to accommodate all of the objects to be weighed
discharged from the weighing hoppers 1 into the collecting hopper 4.
In this case, since all of the objects to be weighed discharged
from the weighing hoppers 1 are temporarily accumulated in the collecting hopper
4, and then discharged into the packaging machine 21, the bag accommodating time
Tb of the objects to be weighed in the packaging machine 21 is reduced, so that
the objects to be weighed are entirely accommodated in the bag within the stopping
time Tc of the horizontal sealing machine 25.
- Patent document 1:
Japanese Utility Model Application Publication No. 62-143601
- Patent document 2:
Japanese Patent Publication No. 3028384
- Patent document 3:
Japanese Laid-Open Patent Application Publication No. 10-77002
Disclosure of the Invention
Problem to be Solved by the Invention
However, in the construction described above in which the
collecting hopper 4 is provided, and the objects to be weighed discharged from weighing
hoppers 1 are temporarily accumulated in the collecting hopper 4 and then discharged
into the packaging machine 21, there has been a problem that, in the case of bulky
(low in bulk density) objects to be weighed such as potato chips, they often get
jammed inside the collecting hopper 4 and fail to fall when the gate 5 is opened,
and that since the objects to be weighed accumulated in the collecting hopper 4
are discharged into the packaging machine at a time, they often get jammed inside
the funnel 22 at the inlet of the packaging machine 21, inside the forming tube
23, and at the inlet of the packaging bag 28, so that the objects to be weighed
fail to fall properly into the packaging bag 28.
The present invention has been made to solve the problem
as mentioned above, and an object thereof is to provide a combination weigher which
can prevent the objects to be weighed from getting stuck in the packaging machine
that is operated at high speeds, and can prevent the phenomenon in which the objects
to be weighed get jammed and fail to fall at the collecting hopper or the like.
Means for Solving the Problem
To achieve the above described object, a combination weigher
of the present invention comprises: a plurality of combination hoppers that are
fed with objects to be weighed; a collecting chute disposed below the plurality
of combination hoppers, which collects the objects to be weighed discharged from
the combination hoppers and discharges the objects to be weighed through an outlet
provided at a lower part thereof; a collecting hopper provided at the outlet of
the collecting chute, which, with a gate provided at a lower part thereof closed,
receives the objects to be weighed discharged from the outlet of the collecting
chute, and, with the gate opened, allows the objects to be weighed to fall into
bags manufactured by a packaging machine; and a control means which determines a
combination of combination hoppers that discharges the objects to be weighed, from
among the plurality of combination hoppers, and causes the combination hoppers forming
the determined combination to discharge the objects to be weighed, and which controls
opening and closing of the gate of the collecting hopper, the combination weigher
having a relationship with the packaging machine in which, a bag accommodating time
required to accommodate from a first-to-arrive to last-to-arrive portion of the
objects to be weighed falling from the collecting hopper into the bag in a case
where the gate of the collecting hopper is always kept open and the objects to be
weighed discharged from the combination hoppers are allowed to pass through the
collecting hopper, is longer than a seal stopping time after completion of sealing
a lower end of any one of the bags successively manufactured by the packaging machine
before start of sealing an upper end of the bag, wherein the control means causes
the gate of the collecting hopper to be closed immediately before any portion of
the objects to be weighed discharged from the combination hoppers arrives at the
collecting hopper at the latest, and causes the gate of the collecting hopper to
be opened before all of the objects to be weighed arrive at the collecting hopper
and after a specified time that elapses from when the gate of the collecting hopper
is closed, such that by keeping the gate of the collecting hopper closed for the
specified time, the bag accommodating time is reduced to be equal to or less than
the seal stopping time of the packaging machine.
With this configuration, by keeping the gate of the collecting hopper closed for
a specified time from prior to arrival of a portion of the objects to be weighed
discharged from combination hoppers at the collecting hopper, the bag accommodating
time is reduced to be equal to or less than the seal stopping time of the packaging
machine, making it possible to prevent the objects to be weighed from getting stuck
in the packaging machine and to thus properly accommodate from tip to tail, of a
batch of the objects to be weighed into a bag. Furthermore, by opening the gate
of the collecting hopper prior to arrival of all of the objects to be weighed at
the collecting hopper, in other words, by opening the gate of the collecting hopper
and discharging the objects to be weighed before all of the objects to be weighed
discharged from combination hoppers are accumulated in the collecting hopper, the
objects to be weighed can fall smoothly from the collecting hopper into the bag.
As a result, the objects to be weighed can be prevented from getting jammed inside
the collecting hopper or at the inlet of the bag in the packaging machine, and can
thus be properly accommodated in the bag.
In the present invention, the combination hoppers may be weighing hoppers that weigh
the weight of the objects to be weighed fed thereinto.
Furthermore, a weighing hopper may be disposed in correspondence
to and above each of the combination hoppers, for weighing the weight of the objects
to be weighed fed thereinto, and the combination hoppers may be memory hoppers that
are fed with the objects to be weighed whose weight has been measured in the weighing
hoppers.
Moreover, the plurality of combination hoppers may be disposed
in two, upper and lower lines, the combination hoppers in the upper line being weighing
hoppers for weighing the weight of the objects to be weighed fed thereinto, and
the combination hoppers in the lower line being memory hoppers which are respectively
provided in correspondence to the weighing hoppers and fed with the objects to be
weighed having been weighed in the weighing hoppers, and the weighing hoppers selectively
discharge the objects to be weighed to the corresponding memory hoppers or to the
collecting chute.
Effect of the Invention
The present invention has the construction as described
above, and a combination weigher has the effect of preventing the objects to be
weighed from getting stuck in a high-speed operated packaging machine and of preventing
the phenomenon in which the objects to be weighed get jammed and fail to fall at
a collecting hopper or the like.
The above object, other objects, features, and advantages of the present invention
will be apparent by reading the following detailed description of a preferred embodiment
of the invention, with reference being made to the accompanying drawings.
Brief Description of Drawings
- [Fig. 1] Fig. 1 is a schematic view showing a construction of a system made
up of a combination weigher and a packaging machine according to an embodiment of
the present invention.
- [Fig. 2] Fig. 2 is a timing chart showing an operation of the combination weigher
and the packaging machine according to the embodiment of the present invention.
- [Fig. 3] Fig. 3 is a schematic view showing a construction of another example
of the combination weigher according to the embodiment of the present invention.
- [Fig. 4] Fig. 4 is a schematic view showing a construction of yet another example
of the combination weigher according to the embodiment of the present invention.
- [Fig. 5] Fig. 5 is a timing chart showing an operation of a conventional combination
weigher which is not equipped with a collecting hopper and a packaging machine.
- [Fig. 6] Fig. 6 is a timing chart showing an operation of a conventional combination
weigher which is provided with the collecting hopper and a packaging machine.
Description of Symbols
- 1: Weighing hopper
- 2: Gate of weighing hopper
- 3: Collecting chute
- 4: Collecting hopper
- 5: Gate of collecting hopper
- 6: Memory hopper
- 7: Gate of memory hopper
- 10: Control unit
- 21: Packaging machine
- 25: Horizontal sealing machine
- 28: Bag
Best Mode for Carrying Out the Invention
Preferred embodiments of the present invention will hereinafter
be described with reference to the drawings.
The schematic construction of a system comprising a combination
weigher and a packaging machine according to an embodiment of the present invention
is shown in the same Fig. 1 as for the prior art example, and detailed description
of the packaging machine, made in connection with the prior art, will be omitted.
The operation of the combination weigher of this embodiment
is entirely controlled by a control unit 10. The combination weigher includes a
plurality of weighing hoppers 1 arranged in a circle shape, a collecting chute 3
provided below the plurality of weighing hoppers 1, and a collecting hopper 4 provided
at an outlet at a lower part of the collecting chute 3. Each weighing hopper 1 is
fed with the objects to be weighed from a feeding hopper or the like (not shown)
disposed thereabove. Furthermore, each weighing hopper 1 is attached with a weight
sensor (not shown), such as a load cell, which measures the weight of the objects
to be weighed inside the weighing hopper 1, and sends the measured value to the
control unit 10. The control unit 10 carries out combination calculation based on
the measured values of a plurality of weighing hoppers 1 so as to select, from among
the plurality of weighing hoppers 1, one combination of hoppers accommodating the
objects to be weighed whose total weight falls within an allowable range with respect
to a target weight. The control unit 10 opens and closes the gates 2 of the weighing
hoppers 1 corresponding to the determined combination, so that the objects to be
weighed are discharged from the weighing hoppers 1. The objects to be weighed discharged
from weighing hoppers 1 slide down on the collecting chute 3, and are sent to the
collecting hopper 4 through the outlet provided at the lower part of the collecting
chute 3. The objects to be weighed are then sent out to the packaging machine 21
while the gate 5 of the collecting hopper 4 is open.
Fig. 2 is a timing chart showing the operation of the combination weigher and the
packaging machine according to the embodiment of the present invention. In Fig.
2, T1 indicates a discharge cycle time of the combination weigher, and T2 indicates
a packaging cycle time that consists of a stopping time Tc and an operating time
(sealing time) Td of the horizontal sealing machine 25 of the packaging machine
21. Since the combination weigher and the packaging machine operate in association
with each other, T1 and T2 become an equal time. Also, Ta indicates a gate open
time of the weighing hopper 1, and Tb indicates a bag accommodating time required
to accommodate from tip to tail of a batch of the objects to be weighed discharged
from the combination weigher into a bag 28 in the packaging machine 21. Te indicates
a gate open time of the collecting hopper 4, and Tf indicates a gate close time
of the collecting hopper 4. The operating time Td of the horizontal sealing machine
25 of the packaging machine 21 is a sealing time period during which the horizontal
sealing machine 25 simultaneously seals (by fusion adhesion) the upper end of a
preceding bag 28 and the lower end of a next following bag. The stopping time Tc
of the horizontal sealing machine 25 is a sealing stopping time period between one
sealing period and next sealing period in the process of sequentially manufacturing
packages. In other words, when attention is paid to a particular bag, the stopping
time Tc is the time that elapses from immediately after the completion of sealing
of the lower end of the bag 28 until the start of sealing of the upper end of the
bag 28. If one batch of the objects to be weighed discharged from the combination
weigher can entirely be accommodated into the bag 28 within that time, then the
objects to be weighed will not get stuck at the horizontal sealing machine 25.
The timing chart of this embodiment shown in Fig. 2 and
the timing chart of a conventional example shown in Fig. 6 differ in opening and
closing timing of the gate 5 of the collecting hopper 4 that is controlled by the
control unit 10.
The timing chart shown in Fig. 5 is for the case where
the collecting hopper 4 is not equipped. In this case, since the bag accommodating
time Tb required to accommodate from tip to tail of the batch of the objects to
be weighed discharged from the combination weigher into the bag 28 of the packaging
machine 21 is longer than the stopping time Tc of the horizontal sealing machine
25 of the packaging machine 21, the objects to be weighed arrive within the time
of the operation of the horizontal sealing machine 25 and get stuck. Likewise, in
the construction in Fig. 1, if the gate 5 of the collecting hopper 4 is not closed
but always kept open, the objects to be weighed discharged from weighing hoppers
1 pass through the collecting hopper 4 and are accommodated into the bag 28, in
which case the bag accommodating time Tb also becomes longer than the stopping time
Tc of the horizontal sealing machine 25, so that the objects to be weighed get stuck
at the horizontal sealing machine 25. If the bag accommodating time Tb is equal
to or less than the stopping time Tc of the horizontal sealing machine 25, then
the objects to be weighed can be prevented from getting stuck. However, in the case
where all of the objects to be weighed discharged are temporarily accumulated in
the collecting hopper 4 as illustrated by the timing chart in Fig. 6, there is a
tendency that the objects to be weighed get jammed in the collecting hopper 4 or
the like and fail to fall therefrom. This phenomenon is obviously observed especially
in the case where the objects to be weighed are bulky (low in bulk density).
Accordingly, in this embodiment, the control unit 10 executes
control such that the gate 5 of the collecting hopper 4 is closed before any part
(the first-to-arrive part at the collecting hopper 4) of the objects to be weighed
discharged from weighing hoppers 1 arrives at the collecting hopper 4, and the gate
5 of the collecting hopper 4 is opened before all of the objects to be weighed discharged
from the weighing hoppers 1 arrive at the collecting hopper 4, and after a specified
time Tf that elapses from when the gate 5 of the collecting hopper 4 is closed.
By keeping the gate 5 of the collecting hopper 4 closed for the specified time Tf
from prior to the arrival of the objects to be weighed at the collecting hopper
4, the bag accommodating time Tb can be decreased to be equal to or less than the
stopping time Tc of the horizontal sealing machine 25, thereby preventing the objects
to be weighed from being stuck at the horizontal sealing machine 25. Furthermore,
by opening the gate 5 of the collecting hopper 4 before all of the objects to be
weighed arrive at the collecting hopper 4, that is, by opening the gate 5 and discharging
the objects to be weighed before all of the objects to be weighed discharged from
the weighing hoppers 1 are accumulated in the collecting hopper 4, a smooth fall
of the objects to be weighed from the collecting hopper 4 into the bag 28 can be
achieved. Thus, the objects to be weighed can be prevented from getting jammed in
the collecting hopper 4, inside the funnel 22 at the inlet of the packaging machine
21, inside the forming tube 23, and at the inlet of the packaging bag 28. As a result,
the objects to be weighed can be properly accommodated into the packaging bag 28.
It should be noted that the timing of closing the gate
5 of the collecting hopper 4 needs to be set to that prior to the arrival of the
first-to-arrive part of the objects to be weighed discharged from weighing hoppers
1 at the collecting hopper 4, and the gate 5 of the collecting hopper 4 may be closed
or opened for a time period from time point in a preceding (last) cycle when the
collecting hopper 4 discharged the objects to be weighed into the packaging machine
and became empty immediately before the first-to-arrive part of the objects to be
weighed discharged from the weighing hoppers 1 arrives at the collecting hopper
4 in a present (current) cycle. It is necessary that the gate 5 be closed immediately
before the first-to-arrive part of the objects to be weighed arrives at the collecting
hopper 4 at the latest.
Furthermore, as to the timing of opening the gate 5 of
the collecting hopper 4, it is preferably opened as soon as possible after the first-to-arrive
part of the objects to be weighed discharged from weighing hoppers 1 has arrived
at the collecting hopper 4, in order to prevent the occurrence of bridging (jam)
of the objects to be weighed. For example, the gate 5 is configured to be opened
before approximately half the total quantity (or approximately half the target weight)
of the objects to be weighed discharged from the weighing hoppers 1 selected to
form a combination are accumulated in the collecting hopper 4. However, it is necessary
that the bag accommodating time Tb be equal to or less than the stopping time Tc
of the horizontal sealing machine 25. Accordingly, it is desirable to open the gate
5 of the collecting hopper 4 such that the bag accommodating time Tb is equal to
or less than the stopping time Tc of the horizontal sealing machine 25, and in particular
is substantially equal to the stopping time Tc.
Description will now be made of specific examples for controlling
the gate opening and closing of weighing hoppers 1 and the collecting hopper 4 by
the control unit 10 in this embodiment.
First, in a first control example, the packaging machine
21 outputs a discharge request signal to the control unit 10 of the combination
weigher at, for example, a start time t1 of the sealing operation of its horizontal
sealing machine 25. Receiving the discharge request signal, the control unit 10
opens the gate 5 of the collecting hopper 4 after a predetermined delay time T3,
and closes the gate 5 after a predetermined gate open time Te. The control unit
10 also opens the gate 2 of the weighing hopper 1 after a predetermined delay time
T4 after opening the gate 5 of the collecting hopper 4, and closes the gate 2 after
a predetermined gate open time Ta. In this case, the specified time Tf for keeping
the gate 5 of the collecting hopper 4 closed is the time obtained by subtracting
the predetermined gate open time Te of the collecting hopper 4 from the discharge
cycle time T1.
Next, in a second control example, the packaging machine
21 outputs a discharge request signal to the control unit 10 of the combination
weigher at, for example, a termination time t2 of the sealing operation of its horizontal
sealing machine 25. Receiving the discharge request signal, the control unit 10
opens the gate 2 of the weighing hopper 1 after a predetermined delay time T5, and
closes the gate 2 after the predetermined gate open time Ta. The control unit 10
also closes the gate 5 of the collecting hopper 4 after a predetermined delay time
T6 after opening the gate 2 of the weighing hopper 1, and opens the gate 5 after
the predetermined gate close time Tf.
In either example, the timing when the packaging machine
21 outputs the discharge request signal is not limited to the start time t1 or the
termination time t2 of the sealing operation by the sealing machine 25, but may
be set at a predetermined point in its cycle time T2, with delay times being varied
in accordance therewith so as to realize the operation as shown in Fig. 2. Moreover,
the above first and second control examples are exemplary, and other control methods
may be employed so long as the operation shown in Fig. 2 is attained.
Whereas in the above embodiment, description has been given
of the case where the hoppers that take part in the combination are weighing hoppers
1, a memory hopper 6 may be provided in correspondence to and directly below each
weighing hopper 1 and may take part in the combination as shown in Fig. 3. In this
case, the weighing hoppers 1 do not take part in the combination, but feed the objects
to be weighed into the memory hoppers 6 when the memory hoppers 6 become empty.
By the combination calculation performed by the control unit 10, a combination of
hoppers accommodating the objects to be weighed whose total weight of the objects
falls within an allowable range with respect to the target weight is selected from
among a plurality of memory hoppers 6, and the objects to be weighed are discharged
from the hoppers forming that combination onto the collecting chute 3. As the weight
of the objects to be weighed in each memory hopper 6, the weight of the objects
to be weighed that has been measured in the weighing hopper 1 thereabove is used
in the combination calculation. In this case, the gate opening and closing timing
for the weighing hopper as shown in Fig. 2 becomes the timing of opening and closing
the gate 7 of the memory hoppers 6 selected to form the combination in Fig. 3. Incidentally,
in the construction of Fig. 3, on condition that a weighing hopper 1 and its corresponding
memory hopper 6 are both selected simultaneously to form a combination, weighing
hoppers 1 may also be allowed to take part in the combination. For example, if a
corresponding weighing hopper 1 and memory hopper 6 are selected simultaneously,
the objects to be weighed in the weighing hopper 1 are discharged through the memory
hopper 6 onto the collecting chute 3. In this case, the gate opening and closing
timing of the weighing hopper shown in Fig. 2 becomes the gate opening and closing
timing of the weighing hopper 1 and memory hopper 6 selected to form the combination.
Whereas in the above embodiment, description has been given
of where the hoppers that take part in the combination are only weighing hoppers
1, a memory hopper 6 may be provided in correspondence to and obliquely downward
of each weighing hopper 1 as shown in Fig. 4 so that both the weighing hopper 1
and the memory hopper 6 take part in the combination. In this case, the weighing
hopper 1 is configured to selectively discharge the objects to be weighed to the
collecting chute 3 or to the memory hopper 6. The memory hopper 6 is fed with the
objects to be weighed from the weighing hopper 1 when the memory hopper 6 becomes
empty. By the combination calculation performed by the control unit 10, a combination
of hoppers accommodating the objects to be weighed whose total weight falls within
an allowable range with respect to the target weight, is selected from among a plurality
of weighing hoppers 1 and memory hoppers 6, and the objects to be weighed are discharged
from the hoppers forming that combination onto the collecting chute 3. As the weight
of the objects to be weighed in each memory hopper 6, the weight of the objects
to be weighed that has been measured in the weighing hopper 1 thereabove is used
in the combination calculation. In this case, the gate opening and closing timing
of the weighing hopper shown in Fig. 2 becomes the gate opening and closing timing
of the weighing hoppers 1 and memory hoppers 6 selected to form the combination
in Fig. 4. In this case, furthermore, by setting the total number of weighing hoppers
1 and memory hoppers 6 equal to the number of weighing hoppers 1 in the construction
of Fig. 1, it becomes possible to achieve substantially the same performance as
in Fig. 1 where only weighing hoppers 1 are provided as the hoppers that take part
in the combination. As a result, the number of expensive load sensors (not shown)
attached to the weighing hoppers 1 can advantageously be reduced by half.
Moreover, the control unit 10 shown in Figs. 1, 3, and 4 is not limited to being
configured as the single control apparatus, but instead may be configured to include
a plurality of control apparatuses which are disposed in a distributed manner, and
co-operate to control the operation of the combination weigher.
Numerous modifications and alternative embodiments of the
invention will be apparent to those skilled in the art in view of the foregoing
description. Accordingly, the description is to be construed as illustrative only,
and is provided for the purpose of teaching those skilled in the art the best mode
of carrying out the invention. The details of the structure and/or function may
be varied substantially without departing from the spirit of the invention and all
modifications which come within the scope of the appended claims are reserved.
Industrial Applicability
The combination weigher of the present invention is useful
as a combination weigher which deals with objects to be weighed that are bulky (small
in bulk density) and so on.