GB2341452A

GB2341452A - Combination weighing or counting apparatus

Info

Publication number: GB2341452A
Application number: GB9819662A
Authority: GB
Inventors: Hiroshi Kishimura; Takashi Kabumoto
Original assignee: Ishida Co Ltd
Current assignee: Ishida Co Ltd
Priority date: 1998-09-09
Filing date: 1998-09-09
Publication date: 2000-03-15
Anticipated expiration: 2018-09-09
Also published as: GB9819662D0; JP4177527B2; GB2341452B; JP2000088634A

Abstract

A combination weighing or counting apparatus includes a plurality of weighing hoppers (10) to which articles (M) are supplied. A combination calculating unit performs a combinational calculation of weighed values or counts of the articles (M) within those weighing hoppers (10) and selects a combination of the weighing hoppers (10, 42) which will give a weight or count closest to a target value or fall within the tolerance range, the combination chosen being one in which the number of the weighing hoppers (10) is a minimum or a maximum. An open/close control unit opens the selected weighing hoppers to allow the latter to discharge the articles (M) therefrom. The control system also acts to exclude the selected weighing hoppers from a subsequent combination calculation.

Description

2341452 The present invention relates to a combination weighing or

counting apparatus of a Idnd operable to dispense articles such as, for example, candies or food materials, into a plurality of weighers, to select, based on result of weight measurements accomplished by the weighers, a combination of the weighers which give rise to a weight closest to a target value and then to discharge the articles therefrom and, more particularly, to the combination weighing or counting apparatus capable of exhibiting a high weighing accuracy and a high operativity.

(Description of the Prior Art)

The combination weighing or counting apparatus is capable of weighing articles of varying weights such as, for example, candies, fruits or processed food materials of varying shapes, to a weight value falling within a target weight range.

An example of this apparatus is disclosed in, for example, the Japanese Laid-open Patent Publication No. 63-30725.

This type of the combination weighing or counting apparatus comprises a plurality of hoppers and a combination calculating means for performing a combinational calculation of measured weights or counts of the articles within the respective weighing hoppers and is so designed as to select a combinafion of the weighing hoppers which give rise to the measured weight or count of the articles falling within a tolerance range and as to discharge the articles from.selected weighing hoppers to thereby provide the articles falling within a target weight range or number. The weighing hoppers from which the articles have been discharged are again supplied with articles immediately after the discharge. During the combination calculation performed by this combination weighing or counting apparatus, where a high speed weighing is required to be achieved, the weighing hoppers which have participated in the previous cycle of combination calculation are not utilized in the subsequent cycle of combination calculation.

With the combination weighing or counting apparatus of the structure described above, however, when a plurality of the weighing hoppers are selected during the combination calculation, the number of the weighing hoppers that can participate in the subsequent cycle of combination calculation is decreased correspondingly and, therefore, it is difficult to select a proper combination of the weighing hoppers. Consequently, the weighing accuracy during the subsequent cycle of combination calculation tends to be lowered.

Also, increase of the frequency of improper combinations as a result of reduction in number of the weighing hoppers in a combination tends to lower the operativity of the combination weighing or counting apparatus.

on the other hand, when hard to flew articles are to be weighed, if the number of the weighing hoppers from which the articles can be discharged as a result of the combination calculation is relatively small, the flow of the articles will be. stagnated and will therefore not be dispensed properly, resulting in stagnatin of is the articles on the transfer feeder then halted. This brings about a frequent occurrence of improper combination of the weighing hoppers.

SUNDJARY OF THE INVENTION Accordingly, the present invention has been devised with a view to substantially eliminating the above discussed problems inherent in the prior art combination weighing or counting apparatus and has for its object to provide an improved combination weighing or counting apparatu s capable of exhibiting a high weighing accuracy and a high operativity.

To this end, the present invention in one aspect provides a combination weighing or counting apparatus which comprises a plurality ofweighing hoppers to which articles are supplied, and a combination calculating means for performing a combinational calculation of weighed values or counts of the articles within those weighing hoppers and for selecting one of combinations of the weighing hoppers which measure respective weight or counts, a combination ofwhich would be closest to a target value or fall within the tolerance range, which one of the combination is a combination ofthe weighing hoppers in which the number of the weighinghoppers is minimum or maximum. An openlclose control means is also provided for opening the selected weighing hoppers to allow the latter to discharge the articles therefrom.

The combination weighing or counting apparatus also comprises an excluding means used for excluding the selected weighing hoppers from a subsequent combination calculation. - With this combination weighing or counting apparatus, during the combination calculation, of combinations of the weighing hoppers which would measure respective weight or counts, a combination of which would be closest to the target value or fall within the tolerance, the combination in which the number of the weighing hoppers is minimum is selected. Accordingly, the number ofthe weighing hoppers which would participate in the subsequent cycle of combination calculation correspondingly increases, accompanied by increase in weighing accuracy. Also, in view of increase of the weighing accuracy, the frequency of the improper combination can advantageously be reduced, accompanied by increase of the operativity of the combination weighing or counting apparatus.

Preferably, the combination calculating means selects one of the combinations in which the number of weighffig heads is minimum, in the event that a deviation between the combined weight or the combined count and the target value is within a head number priority range which is narrower than the tolerance range, such one ofthe combinations being a combination in which the deviation is minimum.

In such case, the combination calculating means preferably selects one of combinations in which the deviation is minimum, in the event-that the deviation between the combined weight or the combined count and the target value is outside the head number priority range, such one of the combinations being a combination in which the number of weighing heads is minimum.

This is particularly advantageous in that by properly setting the head number priority range, the deviation can be preferentially reduced or the number of the weighing heads can be preferentially reduced. In.other words, by narTowing the head number priority range, and by determining the combination in which the deviation is small, outside the large head number priority range, the combination in which the number ofthe weighing heads is minimum can be selected therefrom. On the other hand, by expanding the head number priority range, and by determi i g the combination in which the number of the weighing heads is minimum, within the expanded head number priority range, the combination in which the number of the weighing heads is minimum can be selected therefrom.

The present invention in another aspect provides a combination weighing or counting apparatus which comprises a plurality of weighing hoppers to which articles are supplied, and a combination calculating means for performing a combinational calculation of weighed values or counts of the articles within those weighing hoppers and for selecting one of combinations of the weighing hoppers which measure respective weight or counts, a combination ofwhich would be closest to a target value or fall within the tolerance range, such one of the combination being a combination ofthe weighing hoppers in which the number ofthe weighing hoppers is maximum. The combination weighing or counting apparatus also comprises an open/close control means for opening the selected weighing hoppers to allow them to discharge the articles therefrom, and an excluding means for excluding the selected weighing hoppers from a subsequent combination calculation.

With this combination weighing or counting apparatus, during the combination calculation, of combinations of the weighing hoppers which would measure respective weight or counts, a combination ofwhich would be closest to the target value or fall within the tolerance, the combination in which the number of the weighinghoppers is maximum is selected. Accordingly, the operativityoftheumisfer feeders corresponding to the weighing hoppers can be increased, to thereby facilitate the flowof the articles on the transfer feeders. This means that where the supply of the article tends to be difficult if the flow of the articles is stagnated, the operativity of the combination weighing can be increased.

Preferably, the combination calculating means selects one of the combinations in which the number of weighing heads is maximum, in the event that a deviation between the combined weight or the combined count and the target value is within a head number priority range which is narrower than the tolerance range, such one ofthe combinations being a combination in which the deviation is minimum.

In such case, the combination calculating means preferably selects one of combinations in which the deviation is minimum, in the event that the deviation -<4>- between the combined weight or the combined count and the target value is outside the head number priority range, such one of the combinations being a combination in which the number of weighing heads is maximum.

This is particularly advantageous in that by properly setting the head number priority range, the deviation can be preferentially reduced or the number of the weighing heads can be preferentially increased. In other words, by narrowing the head number priority range, and by determining the combination in which the deviation is small, outside the large head number priority range, the combination in which the number ofthe weighing heads is maximum can be selected therefrom. On the other hand, by expanding the head number priority range, and by determining the combination in which the number ofthe weighing heads is maximum, within the expanded head number priority range, the combination in which the deviation is minimum can be selected therefrom.

In any event, the present invention win become more clearly understood from the following description of preferred embodiments thereof, when taken in conjunction with the accompanying drawings. However, the embodiments and the drawings are given only for the purpose of illustration and explanation, and are not to be taken as limiting the scope of the present invention in any way whatsoever, which scope is to be determined by the appended claims. In the accompanying drawings, like reference numerals are used to denote like parts throughout the several views, and:

Fig. I is a schematic front elevational view, with a portion cut away, of a combination weighing or counting apparatus according to a first preferred embodiment of the present invention; Fig. 2 is a block diagram showing a control system for the combination weighing or counting apparatus shown in Fig. 1; Fig. 3 is a flow chart showing a portion of the sequence of counting operation of the combination weighing or counting apparatus shown in Fig, 1; Fig. 4 is a flow chart showing another portion ofthe sequence of counting operation of the combination weighing or counting apparatus shown in Fig, 1; Figs. 5A to 5C are schematic diagrams showing different contents of a pattern counter used during the operation of the - combination weighing or counting apparatus, respectively; Fig. 6 is a flow chart showing a portion of the sequence of weighing operation in the first embodiment of the present invention; Fig. 7 is a flow chart showing another portion ofthe sequence ofweighing operation in the first embodiment of the present invention; Fig. 8 is a schematic side view showing the combination weighing or counting apparatus according to a second preferred embodiment of the present invention; Fig. 9 is a schematic plan view of the combination weighing or counting apparatus shown in Fig. 8; Fig. 10 is a schematic front elevational view ofthe combination weighing or counting apparatus shown in Fig. 81 Fig. 11 is a flow chart showing a portion of the sequence of combinational counting in the second embodiment of the present invention; Fig. 12 is a flow chart showing another portion of the sequence of combinational counting in the second embodiment of the present invention; Fig. 13 is a flow chart showing a portion ofthe sequence ofcombinational weighing in the second embodiment of the present invention; and Fig, 14 is a flow chart showing another portion of the sequence of combinational weighing in the second embodiment of the present invention; Preferred embodiments of the present invention will hereinafter be described with reference to the accompanying drawings.

Referring to Fig. 1, articles to be weighed M such as, for example, candies which are transported by a delivery conveyor I are supplied through a delivery chute 2 onto a dispensing feeder 3 of a generally flattened conical configuration. This dispensing feeder 3 can be vibrated up and down by the drive of a vibrator 4 to dispense the articles M radially outwardly and downwardly in all direction towards an outer periphery thereof. A plurality of transfer feeders 7 each equipped with a -<6>- vibrator 8 are positioned substantially radially outwardly of and below the outer periphery of the dispensingfeeder 7, and a plurality of pool hoppers 9 are positioned in a circular row at respective locations substantially below downstream ends of the transfer feeders 7. Weighing hoppers 10 equal in number to the number of the pool hoppers 9 are positioned in a circular row at respective locations im mediately below and in alignment with the pool hoppers 9. Each of the pool hoppers 9 has a bottom region opening generally downwardly, which bottom region is adapted to be selectively opened and closed by a gate 13. Similarly, each of the weighing hoppers has a bottom region opening generally downwardly, which bottom region is adapted to be selectively opened and closed by a gate 14.

The transfer feeders 7 are utilized to supply the articles K received from the dispensing feeder 3, onto the corresponding pool hoppers 9 by the effect of vibration effected by the associated vibrators 8, whereas the pool hoppers 9 are utilized to temporarily pool the articles K which have been supplied thereto, and subsequently discharge them onto the weighing hoppers when the respective gates 13 are opened.

Each of the weighing hoppers 10 is supported by a weighing means 11 such as, for example, a load cell for measuring the weight of the article M within the respective weighing hopper 10. A collecting and discharge chute 17 is positioned generally below the weighing hoppers 10 for collecting the articles K discharged from the weighing hoppers 10, at a lower center area.'This collecting and discharge chute 17 includes a plurality of detachable upper chute sections 17a positioned in a circular row below the respective weighing hoppers 10, for receiving the article M from the associated weighing hoppers 10, and a fixed lower chute section 17b common to all ofthe detachable upper chute sections 17a and to which the detachable upper chute sections 17a converge radially downwardly so that the articles M falling along all of the detachable upper chute sections 17a and subsequently emerging outwardly from respective lower discharge ends of the detachable upper chute sections 17a can be collected within the fixed lower chute section l7b. The articles M so collected within the fixed lower chute section l7b are subsequently supplied to a packaging machine 19 through a sorting chute 18.

A support framework 20 fixedly supported above the floor (not shown) has a machine frame 21 fixedly mounted thereon. This machine frame 21 supports a casing 23 by means of a plurality of support legs 22. The delivery chute 2, the dispensing feeder 3, the transport feeders 7 and the pool hoppers 9 are arranged above the casing 23, the weighing hoppers 10 positioned radially outwardly of the casing 23 and the weighing means I I are arranged inside the casing 23. The casing 23 also accommodates therein control units and drive motors both for the pool hopper 9 and the weighing hoppers 10.

Fig. 2 illustrates a block diagram showing a control system employed in the combination weighing or counting apparatus of the structure described above.

Referring to Fig. 2, a gate drive unit 27 for driving the gate 13 of each of the pool hoppers 9 between open and closed positions and a gate drive unit 28 for driving the gate 14 of each of the weighing hoppers 10 between open and closed positions are controlled by a pool hopper open/close control means 29 and a weighing hopper open/close control means 30, respectively. The vibrator 8 of each of the transfer feeders 7 is controlled by a transfer feeder drive control means 31 operable in response to an output from a combination calculating means 37. The vibrator 4 of the dispensing feeder 3 is controlled by a dispensing feeder drive control means 34 operable in response to an output from the combination calculating means 37. One of the transfer feeders 7, one ofthe pool hoppers 9 which is associated with such one of the transfer feeders 7, one of the weighing hoppers 10 which is associated with such one of the pool hoppers 9, one of the weighing means I I which is associate with such one of the weighing hoppers 10, one of the gate drive units 27 which is associated with such one of the pool hoppers 9, and one of the gate drive units 28 which is associated with such one of the weighing hoppers 10 altogether constitute a single weighing head WH and, thus, it will readily be seen that a plurality of the weighing heads WH are arranged radially around the dispensing feeder I A control device 32 which may comprise, for example, a central processing unit (CPU) has the combination calculating means 37 and an excluding means 39 both built-therein. The excluding means 39 is a means operable to exclude one of the weighing hoppers 10, which has been selected as a result of combinational -<S>- calculation, from a group of the weighing hoppers 10 which may participate in a subsequent cycle of combinational calculation.

Figs. 3 and 4 illustrates flow charts showing the sequence of combination counting performed by the combination weighing or counting apparatus. The arithmetic operation of the combination weighing or counting apparatus shown in Figs. 1 and 2 will now be described. In this apparatus, of some of the total counts (the combined numbers) or the total weights (the combined weights) of the articles which fall within the tolerance that establishes a combination selection, a combination which give rise to a minimum number ofthe weighing heads is selected. Where there are a plurality of the minimum combinations, one of the total counts or total weights of the articles which is proximate to a target value is selected. The above described tolerance is, in the illustrated embodiment, defined as a range between the lower limit which is the target value and the upper limit which is of a value somewhat larger than the target value. It is to be noted that prior to the calculation, all of weight values given by the respective weighing hoppers 10 are outputted and stored in a register.

In the first place, the combination calculating means 37 shown in Fig. 2 sets an initial value for the number Sh of the weighing heads, the deviation CDV of the counts and the deviation WDV of the weights (step S 1 in Fig, 3). The weighing head number Sh stands for the number of the weighing heads WH (equal to the number of the weighing hoppers 10) which are selected by the combination calculation. The count deviation CDV stands for the deviation ( 1 Sc - Tc 1) of the total count of the articles M within the selected weighing hoppers 10 from the target number Tc of the articles. The weight deviation "V stands for the deviation ( 1 Sw -Tw 1) ofthe total weight Sw ofthe articles M within the selected weighing hoppers from the target weight Tw of the articles. These initial values are chosen to be of a value sufficiently larger than the value which would actually occur.

Then, the combination calculating means 37 initializes a pattern counter at step S2. In this case, the pattern counter is a binary counter representative of a pattern of combinations of the weighing heads WH that are selected from all of the weighing heads WH which are subject to the combination calculation. Fig. SA -<g>- illustrates a pattern of arbitrary combinations applicable to the pattern counter utilized when the number of the weighing heads WH subject to the combination calculation is ten. Each position in this pattern counter corresponds to the single weighing head WI- and the weighing head WH represented by the position at which the value is "V does participate in the combination calculation, but the weighing head WH represented by the position at which the value is "0" does not participate in the combination calculation. When this pattern counter is initialized, all of the positions assume respective values of " V as shown in Fig. 5B.

At steps S3 and S4, the combination calculating means selects a combination of the weighing heads WH which corresponds to the content of the pattern counter and then calculates the total count Sc and the total weight Sw of the articles M within the weighing hoppers 10 of the weighing heads WH so selected.

At this time, since the pattern counter has been initialized so that all of the weighing beads WH could be selected for participation in the combination calculation, the total count Sc and the total weight Sw of the articles M within the weighing hoppers 10 of all of the weighing heads WH are calculated. It is to be noted that the total count Sc is calculated by determining the number of the articles by dividing the weight of the articles within each weighing hopper 10 by the weight of one article and then totaling the numbers of the articles.

Thereafter, the combination calculating means 37 calculates, at step SS, the number Sh of the weighing heads YM which pa rticipate in the combination calculation, on the basis of the content of the pattern counter. At this time, since the pattern counter has been initialized so that all of the weighing heads WH could be selected for participation in the combination calculation, the number Sh of the weighing heads is equal to the number of all ofthe weighing heads Y7R for example, 10.

The combination calculating means 3 7 calculates, at step S6, the deviations CDV and WDV ofthe total count Sc and the total weight Sw, calculated respectively at steps S4 and SS, from the target count (target value) Tc and the target weight (target value) Tw, respectively.

1 0>- Then, at step S7 shown in Fig. 4, the combination calculating means 37 determines if the current count deviation value CDV calculated at step S6 is a value within a predetermined count deviation range (a head number priority range) which is approximately zero. This head number priority range is defined as a range which is narrower than the tolerance range that is defined as a deviation from the target count Tc of combinations that establish the selection of the combinations. By way of example, where the lower limit of the tolerance range is zero and the upper limit thereof is U 1, the previously discussed head number priority range is so defined as to have its lower limit which is zero and its upper limit U2 which is smaller than U 1.

It is, however, to be noted that the upper limit U2 of the head number priority range maybe set to zero, in which case only the combination which matches with the target count Tc is determined as falling within the head number priority range and, in case a plurality of such combinations were obtained, the combination in which the number of the weighing beads is smaller can be preferentially selected.

If at step S7 the current count deviation value CDV is not found within the head number priority range, the combination calculating means compares, at step S8, the count deviation value CDV, which has been saved, with the current count deviation value CDV calculated at step S6. It is to be noted that since at the first cycle of comparison, the count deviation value CDV which has been saved is the initial value, that is, a value sufficiently larger than a value which would actually occur, the current count deviation value CDV becomesa value smaller than the count deviation value CDV which has been saved until that time. - At this time, the combination calculating means 37 saves, at step S9, the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV in place ofthe previously saved weighing head number Sh, the previously saved count deviation value CDV and the previously saved weight deviation value WDV, respectively.

At the subsequent step S 10 shown in Fig. 3, the combination calculating means 3 7 subtract one from the content ofthe pattern counter. In this way, the pattern ofcombination of the weighing heads YM represented by the pattern counter changes.

In other words, as shown in Fig. SC, the first digit of the pattern counter becomes -<li>- zero and, ofthe total weighing heads WH that are taken into consideration in selecting the combination, only the weighing head WH coffesponding!o the first digit of the pattern counter which has now become zero is excluded from the pattern of combination.

If at step SS shown in Fig. 4 it-is determined that the current count deviation value CDV is larger than the currently saved count deviation value CDV, the program flow goes to step S 10 shown in Fig. 10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re-saved, at which step S 10 the content of the pattern counter is decremented only by 1 to thereby provide a new pattern of combination of the weighing heads YM.

Also, if at step S8 it is determined that the current count deviation value CDV and the currently saved count deviation value CDV are equal to each other, the combination calculating means 3 7 performs a comparison step S 11 at which the currently saved weighinghead number $h is compared with the current weighinghead number Sh. If the current weighing head number Sh is found to be smaller than the currently saved weighing head number Sh, the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV are saved at step S9 in place of the currently saved weighing head number Sh, the currently saved count deviation value CDV and the currently saved weight deviation value WM, respectively.

Also, if at step S 1 lit is determined that the current weighinghead number Sh is larger than the currently saved weighing head number Sh, the program flow goes to step S 10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDY being re-saved, at which step S 10 the content of the pattern counter is decremented only by 1 to thereby provide a new pattern of combination of the weighing heads WH.

On the other hand, if at step S 11 it is determined that the current weighing head number Sh is equal to the currently saved weighing head number Sh, the combination calculating means 37 examines the weight deviation. In other words, the program flow goes to step S 12 at which the currently saved weight deviation value -<1>- WDV is compared with the current weight deviation value WDY If at this time the current weight deviation value WDV is found to be smaller thn the curTently saved weight deviation value WDV, the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV are saved at step S9 in place of the currently saved weighing head number Sk the currently saved count deviation value CDV and the currently saved weight deviation value WDV, respectively.

If at step S 11 it is determined that the current weight deviation value WDV is larger than the currently saved weight deviation value WM, the program flow goes to step S 10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re-saved, at which step S 10 the content of the pattern counter is decremented only by 1 to thereby provide a new pattern of combination of the weighing heads WH. If at step S7 shown in Fig. 4 the current count deviation value CDV is

foundtobe withinthe head number priority range, the combination calculating means 3 7 performs a comparison step S 13 to compare the currently saved weighing head number Sh with the current weighing head number Sh. If at this time the currently saved weighing head number Sh is smaller than the current weighing head number Sh, the program flow goes to step S 10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re- saved.

On the other hand, if at step S 13 the current weighing head number Sh is found to be smaller than the currently saved weighing head number Sk the program flow goes to step S9 at which the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV are saved in place ofthe currently saved weighing head number Sh, the currently saved count deviation value CDV and the currently saved weight deviation value WM, respectively.

Should the decision at step S 13 indicate that thecurrent weighing head number Sh and the currently saved weighing head number Sh are equal to each other, the combination calculating means 3 7 performs a comparison step S 14 to compare the currently saved count deviation value CDV with the current count deviation value CDV. If at this time the current count deviation value CDV is found to be smaller -<1>- than the currently saved count deviation value CDV, the program flow goes to step S9 at which the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV are saved in place ofthe currently saved weighing head number Sh, the currently saved count deviation value CDV and the currently saved weight deviation value WM, respectively.

Where the decision at step S 14 indicates that the current count deviation value CDV is larger than the currently saved count deviation value CDV, the program flow goes to step S 10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re-saved, at which step S 10 the content of the pattern counter is decremented only by 1 to thereby provide a new pattern of combination of the weighing heads WH.

On the other hand, where the decision at step S 14 indicates that the current count deviation value CDV is equal to the currently saved count deviation value CM, the combination calculating means 37 performs a comparison step S15 tocompare the currently weight deviation value WIDV with the currently saved weight deviation value WDY If at this time the current weight deviation value WDV is found to be smaller than the currently saved weight deviation value WDV, the program flow goes to step S9 at which the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV are saved in place of the currently saved weighing head number Sh, the currently saved count deviation value CDV and the currently saved weight deviation value WDV, respectively.

Should the decision step S 15 indicate that the current count deviation value CDV is larger than the currently saved count deviation value CDV, the program flow goes to step S 10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re-saved, at which step S 10 the content of the pattern counter is decremented only by 1 to thereby provide a new pattern of combination of the weighing heads WH. - After the process at step S 10 shown in Fig. 3, and if as a result of decision at step S 16 shown in Fig. 3 the content of the pattern counter is found not to be "0", the combination ca lculating means 37 repeats the flow from step S3 to step S10. In this way, the above described combination calculation is carried out with respect to -<14>all combinations of the weighing heads WH. Upon completion of this combination calculation as determined at step S 16, the combination calculating means 3 7 determines at step S 17 if the currently saved count deviation value CDV is within the previously discussed tolerance range. In such case, the tolerance range for the count deviation value CDV is so set as to encompass the head number priority range at step S7 and as to be larger than this head number priority range as hereinbefore described.

If at step S7 the count deviation value CDV is found to be outside the head priority range, steps S8, S9, S I I and S 12 shown in Fig. 4 are successively executed and, therefore, a combination which renders the count deviation value CDV to be of a minimum value within the range outside the head priority range is preferentially determined and the combination which renders the weighing head number to be of a minimum value can be selected. Accordingly, the narrower the head priority range, the larger the range in which a priority is given to the minimum value of the count deviation value CDV, rather than to the minimum value ofthe head number. By way of example, if the head priority range is rendered to be zero, of all combinations, the combination in which the count deviation value CDV is of the minimum value is determined and, therefrom, the combination in which the weighing head number is of the minimum value is selected. On the other hand, if the head priority range at step S7 is expanded, within the expanded ranges steps S 13, S 14, S 15 and S9 are successively executed and, therefore, the combination in which the weighing head number is of a minimum value is preferentially determined and, therefrom the combination in which the count deviation value CDV is of the minimum value is selected.

Should the decision step S 17 indicate that the count deviation value CDV is within the above described tolerance range, the program flow goes to step S 18 at which the combination calculating means 37 makes a decision to determine if the currently saved weight deviation value WDV is within the tolerance range corresponding to the tolerance range for the above described count deviation value CDV.

-<15>- If as a result of decision at step S 18 the weight deviation value WDV is found to be within the range of above described tolerance range, a combination of the weighing heads WH having the currently saved weighing head number Sh, the currently saved count deviation value CDV and the currently weight deviation value WDV is selected. In other words, the combination of the weighing head WH sufficient to permit the count deviation value CDV and the weighing head number Sh to be of respective minimum values is selected. Where there are a number of combinations sufficient to permit both of the count deviation value CDV and the weighing head number Sh to be of a minimum values, the combination of the weighing heads WH ellective to render the weight deviafion value WDV to be of a mmunum value is selected.

In response to the result of this combination calculafion, the respective gates 14 of the weighing hoppers 10 corresponding to the selected combination of the weighing heads WH are opened by the associated gate drive units 28 then controlled by the corresponding weighing hopper open/close control means 30, to thereby discharge the articles M at step S 19. The articles M so discharged are, after having been collected by the collecting and discharge chute 17 shown in Fig. 1, supplied through the sorting chute 18 to the packaging machine 19 and are then packaged by such packaging machine 19.

In the next place, the excluding means 3 9 executes, at step S20, a process of storing the weighing heads WH which have participated in the above described combination weighing and excluding those weighing heads WH from the subsequent cycle of combination weighing.

If at successive steps S 17 and S IS, the currently saved count deviation value CDV or the weight deviation value WDV is found to be not within the tolerance range, by controlling the gate drive units 28 by means of the weighing hopper open/close control means 30, a miss process is carried out at step S21 to open the gates 14 of some of the weighing hoppers 10 according to a predetermined selection rule to thereby discharge the articles M from such some of the weighing hoppers 10.

The articles M then discharged are discharged to a location outside the packaging -<16>- machine 19 by means of the sorting chute 18 then held at a position shown by the double-dotted line and will not be used as products.

In this combination weighing or counting apparatus, since during the combination calculation, of combinations of the weighing hoppers 10 which result in the weighed count of the articles M falling within the tolerance range, the combination in which the number ofthe weighing hoppers 10 is minimum is selected, the number of the weighing hoppers 10 which participate in the subsequent cycle of combination calculation can be correspondingly increased and, therefore, the weighing accuracy can be increased. Also, in view of increase of the weighing accuracy, the frequency of combinations of the weighing hoppers 10 in which the count of the articles M is outside the tolerance range can be minimized and, therefore, the operativity of the combination weighing or counting apparatus can correspond ingly be increased.

It is to be noted that in the above described combination calculation, after of all possible combinations of the weighing hoppers 10, the combination in which the count deviation value CDV is minimum and the number of the weighing hoppers is smallest has been selected, a decision is made to determine if the count deviation value CDV in that combination falls within the tolerance range. However, arrangement may be made that of all possible combination of the weighing hoppers 10, the combinations in which the count deviation value CDV falls within the tolerance range are successively saved and one of the combinations in which the number ofthe weighing hoppers is minimum is finally selected. In such case, it may occur that even though the count deviation value CDV falls within the tolerance range, the total count of the articles (the number of combinations) which is not most approximate to the target article count will be selected.

Figs. 6 and 7 illustrates the flow of operation ofthe combination weighing or counting apparatus of Fig. I to perform a combinational weighing ofthe respective weights of the articles M.

In this operation, since the counts of the article M are not subjected to the combinational weighing, the process at step S3 shown in the flow of Fig. 3, that is, a process of calculating the total article count Sc of the combined weighing heads -<17>- WH is not executed, but for calculation of the deviation value, only the weight deviation value "V is calculated (at step R5 shown in Fig.. 6). Even during the initialization at step R 1, the count deviation value CDV is not initialized. Also, after calculation of the weight deviation value WDV, the combination calculating means 37 makes a decision at step R6 to determine if this weight deviation value WDV is a value falling within a predetermined weight range (head number priority range).

This head number priority range is, as is the case with that in the previously described combination calculation, defined as a range narrower than the tolerance range defined as a deviation from the target weight Tw of combinations that establish the selection of the combinations. This head number priority range has, in the illustrated embodiment the lower limit which is set to zero and the upper limit which is of a value sufficiently smaller than the upper limit of the tolerance range. It is, however, to be noted that the upper limit of this head number priority range may be set to zero.

If at step R6 the current weight deviation value V;IDV is found to be not within the head number priority range, the combination calculating means 37 compares, at step R7, the currently saved weight deviation value WDV with the current weight deviation value WDY Should the current weight deviation value WDV be found to be smaller than the currently saved weight deviation value WDV as a result of comparison at step R7, the combination calculating means 3 7 saves, at step R8, the current weighing head number Sh and the current weight deviation value WDV in place ofthe currently saved weighing head number Sh and the currently saved weight deviation value WDV, respectively. Thereafter, the program flow goes to step R9 shown in Fig. 6 at which the content of the pattern counter is decremented by one to thereby provide a new pattern of combination of the weighing heads W11.

in the event that at step R7 shown in Fig. 7 the current weight deviation value WDV is found to be larger than the currently saved weight deviation value WDV, the combination calculating means 37 performs a process of step R9 without the weighing head number Sh and the weight deviation value "V being re- saved, -< 1 8>- at which step R9, the content of the pattern counter is decremented by one to thereby provide a new pattern of combination of the weighing heads)VH.

Also, in the event that at step R7 the current weight deviation value WDV is found to be equal to the currently saved weight deviation value "V, the combination calculating means 37 perforTns a comparison step R 10 to compare the currently saved weighing head number Sh with the current weighing head number Sh. If at this time the current weighing head number Sh is found to be smaller than the currently saved weighing head number Sh, the current weighing head number Sh and the current weight deviation value WDV are saved at step RS in place of the currently saved weighing head number Sh and the currently saved weight deviation value VYIDV, respectively.

On the other hand, if at step R 10 the current weighing head number Sh is found to be larger than the currently saved weighing head Sh, the program flow goes to step R9 without the weighing head number Sh and the weight deviation value WDV being re-saved, at which step R9 the content of the pattern counter is decremented by one to provide a new pattern of combination of the weighing heads If at step R6 the current weight deviation value WDV is found to be within the head number priority range, the combination calculating means 37 performs a comparison step R1 1 to compare the currently saved weighing head number Sh with the current weighing head number Sh. If the current weighing head number Sh is found tote smaller than the currently saved weighing head number Sh, the program flow goes to step R8 at which in place of the previously saved weighing head number Sh and the previously saved weight deviation value WDV the current weighing head number Sh and the weight deviation value WDV are saved respectively.

If the decision at step R 11 indicates that the current weighing head number Sh is larger than the currently saved weighing head number Sh, the combination calculating means 37 performs a process of step R9 without the weighing head number Sh and the weight deviation value WDV being re-saved, at which step R9 the content of the pattern counter is decremented by one to provide a new pattern of combination of the weighing heads WH.

-<lg>- If the decision at step R 11 indicates that the current weighing head number Sh is equal to the currently saved weighing head number Sh, the combination calculating means 3 7 performs a comparison step R 12 to compare the currently saved weight deviation value WDV with the current weight deviation value WDY If as a result of comparison the current weight deviation value WDV is smaller than the currently saved weight deviation value WDV, the program flow goes to step R8 at which the current weighing head number Sh and the current weight deviation value "V are saved in place of the currently saved weighing head number Sh and the currently saved weight deviation value WDV, respectively.

Where a decision at step R 12 indicates that the current weight deviation value WDV is larger than the currently saved weight deviation value WM, the program flow goes to step R9 without the weighing head number Sh and the weight deviation value VMV being re-saved, at which step R9 the content of the pattern counter is decremented by one to provide a new pattern of combination of the weighing heads WH.

After the combination calculation with respect to all possible combinations ofthe weighing heads WH completes at step R1 3, the combination calculating means 37 determines at step R14 if the currently saved weight deviation value WDV is within the range ofthe previously described tolerance range. If as a result of decision at step R14 the currently saved weight deviation value WDV is found to be within the range of the tolerance range, a combination of the weighing heads WH having the currently saved weighing head number Sh and the currently saved weight deviafion value WDV is selected. Other operations are identical with those shown in the flow of Fig, 3.

Even in this case, since during the combination calculation, of combina tions of the weighing hoppers 10 which result in the total weight of the articles M falling within the tolerance range, the combination in which the number of the weighing hoppers 10 is minimum is selected, the number of the weighing hoppers which participate in the subsequent cycle of combination calculation can be correspondingly increased and, therefore, the weighing accuracy can be increased.

Also, in view of increase of the weighing accuracy, the firequency of combinations -<0>- of the weighing hoppers 10 in which the total weight of the articles M is outside the tolerance range can be minimized and, therefore, the operativi.ty of the combination weighing or counting apparatus can correspondingly be increased.

Also, even in this case, arrangement may be made that of all possible combination of the weighing hoppers 10, the combinations in which the weight deviation value WDV falls within the tolerance range are successively saved and one of the combinations in which the number of the weighing hoppers is minimum is finally selected. In such case, it may occur that even though the weight deviation value WDV falls within the tolerance range, the total weight of the articles (the combined weight) which is not most approximate to the target article weight will be selected.

Fig. 8 illustrates, in a schematic representation of the combination weighing or counting apparatus according to another preferred embodiment of the present invention. The combination weighing or counting apparatus shown in Fig.

8 is a so-called in-line design which comprises a plurality of transfer feeders 41 for successively transporting the articles M which have been successively supplied from a delivery hopper 40 positioned thereabove. The combination weighing or counting apparatus also comprises a plurality of weighing hoppers 42 each disposed below a downstream end of each of the transfer feeders 41 for receiving the article M fed by the respective transfer feeder 4 1. As is the case with the previously described embodiment of the present invention, each of the weighing hoppers 41 has a bottom region adapted to be selectively opened and closed by a gate 43 which is driven by a corresponding gate drive unit 44 and the gate drive unit 44 for each of the weighing hoppers 41 is controlled by a weighing hopper open/close control means 45. Each of the transfer feeders 41 includes an upstream vibratory feeder 41a adjacent the delivery hopper 40 and a downstream vibratory feeder 4 lb adjacent the associated weighing hopper 42.

As shown in a plan view in Fig. 9, the transfer feeders 41 are arranged in side-by-side fashion and are operable to transport the articles K supplied under the influence of a gravitational force from the single delivery hopper 40, while they are vibrated by a vibrator 46 shown in Fig. 9, towards the respective weighing hoppers -<1>- 42 arranged in a linear row along the respective downstream ends of the transfer feeders 4 1. The vibrator 46 for the transfer feeders 41 is controlled by a transfer feeder drive control means 50.

The weighing hoppers 42 are supported by weighing means 47 for weighing the articles M accommodated within those weighing hoppers 42. A single weighing head WH is constituted by any one of the transfer feeders 4 1, the weighing hopper 42 associated with such one of the transfer feeder 41 and the weighing means 37 also associated therewith, and the plural weighing heads WH are arranged horizontally in a juxtaposed fashion. A collecting and discharge chute 5 1 is positioned below the weighing hoppers 42 for collecting and discharging downwardly the articles M which have been supplied under the influence of a gravitational force from those weighing hoppers 42.

As shown in Fig. 10, positioned below the collecting and discharge chute 1 is a container 52 for accommodating the articles M discharged from a discharge opening 5 la of the collecting and discharge chute 5 1. A control device 55 shown in Fig. 88 comprises a central processing unit (CPU) with both of a combination calculating means 57 and an excludingmeans 59 builttherein as isthe case withthose in the previously described embodiment.

Figs. 11 and 12 illustrate flow charts showingthe sequence ofcombination counting performed by the combination weighing or counting apparatus. The combination counting operation of the combination weighing or counting apparatus of Fig. 8 will now be described with reference to Figs. 11 and 12.

At th e outset the combination calculating means 57 sets respective initial values for the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV at step NI, followed by initialization of the pattern counter at step N2, as is the case with the previously described embodiment of the present invention which has been described with reference to Figs. 3 and 4. It is, however, to be noted that in the second embodiment of the present invention, the weighing head number Sh is set to a value, for example, zero, which is smaller than the value which would actually occur.

-<22>- The operation that follows is substantially identical with that described in connection with the previous embodiment of the present invention with reference to Figs. 3 and 4, except for steps N 11 and N 13 shown in Fig. 12. More specifically, if at step N7 the current count deviation value CDV is found to be not within the head number priority range, the combination calculating means 57 compares, at step N8, the currently saved count deviation value CDV with the current count deviation value CDV calculated at step N6. Since at the first cycle of comparison, the count deviation value CDV which has been saved is the initial value, that is a value sufficiently larger than a value which would actually occur, the current count deviation value CDV becomes a value smaller than the count deviation value CDV which has been saved until that time.

At this time, the combination calculating means 57 saves, at step N9, the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV in place ofthe previously saved weighing head number Sh, the previously saved count deviation value CDV and the previously saved weight deviation value "V, respectively.

The program flow then goes to step NI 0, shown in Fig. 11, at which the combination calculating means 57 subtracts one from the content of the pattern counter. In this way, the pattern of combination of the weighing heads WH represented by the pattern counter changes.

If at step N8 shown in Fig, 12 it is determined that the current count deviation value CDV is larger than the currently saved count deviation value CDV, the program flow goes to step N 10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re-saved, at which step NIO the content of the pattern counter is decremented only by 1 to thereby provide a new pattern of combination of the weighing heads WH.

Also, if at step N8 it is determined that the current count deviation value CDV and the currently saved count deviation value CDV are equal to each other, the combination calculating means 57 performs a comparison step NI 1 at which the currently saved weighinghead number Sh iscomparedwith the current weighing head number Sh. If the current weighing head number Sh is found to be larger than the -<2>- currently saved weighing head number Sh, the current weighing head number Sh, the current count deviation value CDV and the current weight deviation value WDV are re-saved at step N9.

On the other hand, if the comparison at step N 11 indicates that the current weighing head number Sh is smaller than the currently saved weighing head number Sh, the program flow goes to step NI 0 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re- saved, at which step N 10 the content of the pattern counter is decremented only by 1 to thereby provide a new pattern of combination of the weighing heads WE If at step N 11 it is determined that the current weighing head number Sh is equal to the currently saved weighing head number Sk the combination calculating means 57 performs a comparison step N12 to compare the currently saved weight deviation value WDV with the current weight deviation value WDY This comparison at step N 12 is substantially identical with that performed at step S 12 described in connection with the previously described embodiment with reference to Figs. 3 and 4. In other words, only when the current weight deviation value WDV is smaller than the currently saved weight deviation value WDV, re-saving takes place at step N9.

if at step N7 shown in Fig. 12 the current count deviation value CDV is found to be within the head number priorityrange, the combination calculating means 57 performs a comparison step N13 to compare the currently saved weighing head number Sh with the current weighing head number Sh. If at this time the currently saved weighing head number Sh is larger than the current weighing head number Sh, the program flow goes to step N9 at which the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV are re-saved On the other hand, if at step N 13 the current weighing head number Sh is found to be smaller than the currently saved weighing head number Sh, the program flow goes to step N10 without the weighing head number Sh, the count deviation value CDV and the weight deviation value WDV being re-saved, at which step N 10 the content of the pattern counter is decremented by one to provide a new pattern of combination of the weighing heads WH.

-<4>- Should the decision at step N 13 indicate that the current weighing head number Sh and the currently saved weighing head number Sh are equal to each other, the combination calculating means 57 performs a comparison step N14 to compare the currently saved count deviation value CDV with the current count deviation value CDV. Comparison performed at successive steps N14 and N15 is substantially identical with that performed at successive steps S 14 and S 15 shown in Figs. 3 and 4 in connection with the previously described embodiment.

After the process at step N 10 shown in Fig. 11, and if as a result of decision at step N 16 the content of the pattern counter is found not to be "0", the combination calculating means 57 repeats the flow from step N3 to step N10.

The above described process flow is carried out with respect to all combinations of the weighing heads W11. Upon completion of this combination calculation as determined at step N16, the combination calculating means 57 determines at step NI 7 if the currently saved count deviation value CDV is within the tolerance range. In such case, the relationship between the tolerance range for the count deviation value CDV and the head number priority range is substantially identical with that shown and described in connection with the previous embodiment with reference to Figs. 3 and 4, or the latter is narrower than the former.

If at step N7 the count deviation value CDV is found to be outside thehead priority range, steps S8, S9, S 11 and S 12 are successively executed to determine a combination which renders the count deviation value CDV to be of a minimum value within the range outside the head priority range, and of them the combination in which the number of the weighing heads is maximum is selected- Accordingly, the narrower the head priority range, the larger the range in which a priority is given to the minimum value of the count deviation value CM, rather than to the maximum value of the head number. By way of example, if the head priority range is rendered to be zero, of all combinations, the combination in which the count deviation value CDV is ofthe minimum value is determined and, therefrom, the combination in which the weighing head number is of the maximum value is selected. On the other hand, if the head priority range at step S7 is expanded, within the expanded ranges steps S 13, S 14, S 15 and S9 are successively executed and, therefore, the combination in -<25>- which the weighing head number is ofa maximum value is preferentially determined and, therefrom the combination in which the count deviation value CDV is of the minimum value is selected.

Should the decision step N 17 indicate that the count deviation value CDV is within the above described tolerance range, the program flow goes to step N 18 at which the combination calculating means 57 makes a decision to determine if the currently saved weight deviation value WDV is within the tolerance range corresponding to the tolerance range for the above described count deviation value CDV.

If as a result of decision at step N IS the weight deviation value WDV is found to be within the range of above described tolerance range, a combination of the weighing heads WH having the currently saved weighing head number Sh, the currently saved count deviation value CDV and the currently weight deviation value WDV is selected. In other words, the combination of the weighing head WH sufficient to permit the count deviation value CDV to be of the minimum value and the weighing head number Sh to be ofthe maximum value. Where there are a number of combinations sufficient to permit the count deviation value CDV to be of the minimum value and the weighing head number Sh to be of the maximum value, the combination ofthe weighing heads WH effective to render the weight deviation value WDV to be of a minimum value is selected. Other operations are substantially identical with those shown in the flow of Figs. 3 and'4.

In this combination weighing or counting apparatus, since during the combination calculation, of combinations of the weighing hoppers 42 which result in the weighed count of the articles M falling within the tolerance range, the combination in which the number ofthe weighing hoppers 42 is maximum is selected, the number of the weighing hoppers 42 which participate in the subsequent cycle of combination calculation can be correspondingly degeased. In other words, in the combination weighing or counting apparatus in which the plural transfer feeders 41 associated with the weighing hoppers 42 are juxtaposed as shown in Fig. 9, the number of the weighing hoppers 42 to which supply of the articles M from the transfer feeders 41 is interrupted can be correspondingly decreased. Accordingly, -<26>- since the flow of the articles M through the transfer feeders 41 becomes smooth and since there is less possibility that a bulk of the articles M jammed on one or some of the transfer feeders 41 may fall onto the weighing hoppers 42, the weighing accuracy can be increased. Also, in view of increase of the weighing accuracy, the frequency of combinations of the weighing hoppers 10 in which the count of the articles M is outside the tolerance range can be minimized and, therefore, the operativity of the combination weighing or counting apparatus can correspondingly be increased.

It is to be noted that in the above described combination calculation, after of all possible combinations of the weighing hoppers 42, the combination in which the count deviation value CDVis minimum - and the number of the weighing hoppers 42 is greatest has been selected, a decision is made to determine if the count deviation value CDV in that combination falls witii_the tolerance range. However, arrangement may be made that of all possible combination of the weighing hoppers 42, the combinations in which the count deviation value CDV falls within the tolerance range are successively saved and one of the combinations in which the number of the weighing hoppers is maximum finally selected. - In such case, it may occur that even though the count deviation value CDV falls within the tolerance range, the total count ofthe articles which is not most approximate to the target article count will be selected.

Figs. 13 and 14 illustrates the flow of operation of the combination weighing or counting apparatus ofFig. 8 to perform a combinational weighing ofthe respective weights of the articles M.

Since this operation is not to perform a combinational counting of the counts of the article n the process at step N3 shown in the flow of Figs. 11 and 12, that is, a process of calculating the total article count Sc of the combined weighing heads WH is not executed, but for calculation of the deviation value, only the weight deviation value WDV is calculated atstep M5. Even during the initialization at step M 1, the count deviation value CDV is not initialized. Also, after calculation of the weight deviation value WDV, the combination calculating means 57 makes a decision at step M6 to determine if this weight deviation value WDV is a value falling within -<V>- a predetermined weight range (head number priority range) which is approximate to the target weight Tw.

The operation that follows is substantially identical with that shown in Figs. 6 and 7 in connection with the previously described embodiment except for steps M 10 and M 11. Specifically, if at step M6 shown in Fig. 14, the current weight deviation value WDV is found to be not within the head number priority range'. the combination calculating means 57 performs a comparison step M7 to compare the currently saved weight deviation value WDV with the current weight deviation value WDY Should the current weight deviation value VYIDV be found to be smaller than the currently saved weight deviation value WDV as a result of comparison at step M7, the combination calculating means 57 saves, at step M8, the current weighing head number Sh and the current weight deviation value "V in place of the currently saved weighing head number Sh and the currently saved weight deviation value WDV, respectively. Thereafter, the program flow goes to step M9 shown in Fig. 13 at which the content of the pattern counter is decremented by one to thereby provide a new pattern of combination of the weighing heads WH.

In the event that at step M7 shown in Fig. 14 the current weight deviation value WDV is found to be larger than the currently saved weight deviation value WDV, the combination calculating means 5 7 performs a process of step M9 without the weighing head number Sh and the weight deviation value W1W being re- saved, at which step M9, the content of the pattern counter is decremented by one to thereby provide a new pattern of combination of the weighing heads WIL Also, in the event that at step M7 the current weight deviation value WDV is found to be equal to the currently saved weight deviation value WDV, the combination calculating means 57 performs a comparison step M 10 to compare the currently saved weighing head number Sh with the current weighing head number Sh. If at this time the current weighing head number Sh is found to be larger than the currently saved weighing head number Sh, the current weighing head number Sh and the current weight deviation value WDV are saved at step M8 in place of the -<U>- currently saved weighing head number Sh and the currently saved weight deviation value WDV, respectively.

On the other hand, if at step M 10 the current weighing head number Sh is found to be smaller than the currently saved weighing head Sh, the program flow goes to step M9 without the weighing head number Sh and the weight deviation value WDV being re-saved, at which step M9 the content of the pattern counter is decremented by one to provide a new pattern of combination of the weighing heads WR If at step M6 the current weight deviation value WDV is found to be within the head number priority range, the combination calculating means 57 performs a comparison step M 11 to compare with currently saved weighing head number Sh with the current weighing head number Sh. If the current weighing head number Sh is found to be larger than the currently saved weighing head number Sk the program flow goes to step Mt at which in place ofthe previously saved weighing head number Sh and the previously saved weight deviation value WDV the current weighing head number Sh and the weight deviation value WDV are saved respectively, If the decision at step M 11 indicates that the current weighinghead number Sh is smaller than the currently saved weighing head number Sh, the combination calculating means 57 performs a process of step M9 without the weigh ing head number Sh and the weight deviation value WDV being re-saved, at which step M9 the content of the pattern counter is decremented by one to pro%de a new pattern of combination of.the'weighing heads W11.

If the decision at step M 11 indicates that the current weighing head number Sh is equal to the currently saved weighing head number Sh, the combination calculating means 57 performs a comparison step M 12 to compare the currently saved weight deviation value "V with the current weight deviation value WDY This comparison step M 12 is substantially identical with the comparison step R 12 in the previously described embodiment shown in Figs. 6 and 7 and, only when the current weight deviation value WDV is smaller than the currently saved weight deviation value WM, the program flow goes to step M8 at which the current weighing head number Sh and the current weight deviation value WDV are re-saved. Other -<9>- operations are identical with those shown in the previously described embodi ment.

Even in this case, since during the combination calculation, of combina tions of the weighing hoppers 42 which result in the weighed count of the articles M falling within the tolerance range, the combination in which the number of the weighing hoppers 42 is maximum is selected, the number of the weighing hoppers 42 to which supply of the articles M from the transfer feeders 41 is interrupted can be correspondingly decreased. Accordingly, since the flow of the articles M through the transfer feeders 41 becomes smooth, the weighing accuracy can be increased.

Also, in view of increase of the weighing accuracy, the frequency of combinations of the weighing hoppers 42 in which the count of the articles M is outside the tolerance range can be minimized and, therefore, the operativity of the combination weighing or counting apparatus can correspondingly be increased.

Also, even in this case, arrangement may be made that of all possible combination of the weighing hoppers 42, the combinations in which the weight deviation value WDV falls within the tolerance range are successively saved and one ofthe combinations in which the number ofthe weighing hoppers is maximum is firdly selected. In such case, it may occur that even though the weight deviation value WDV falls within the tolerance range, the total weight of the articles which is not most approximate to the target article weight wW be selected.

As hereinbefore fully described with the combingtion weighing or counting apparatus according to one aspect of the present invention, during the combination calculation, of combinations of the weighing hoppers which would measure respective weight or counts, a combination ofwbich would be closest to the target value or fall within the tolerance, the combination in which the number of the weighing hoppers is minimuni is selected. Accordingly the number ofthe weighing hoppers which would participate in the subsequent cycle of combination calculation correspondingly increases, accompanied by increase in weighing accuracy. Also, m view of increase of the weighing accuracy, the frequency of combinations of the weighing hoppers in which the weighed value or count of the articles is outside the _<3>_ tolerance range can be minimized and, therefore, the operativity of the combination weighing or counting apparatus can correspondingly be increased.

Also, with the combination weighing or counting apparatus according to another aspect of the present invention, during the combination calculation, of combinations of the weighing hoppers which would measure respective weight or counts, a combination ofwhich would be closest to the target value or fall within the tolerance, the combination in which the number ofthe weighing hoppers is maximum is selected. Accordingly the number of the weighing hoppers to which supply of the articles from the transfer feeders is interrupted correspondingly decreases, accompanied by increase in weighing accuracy. Also, in view of increase of the weighing accuracy, the frequency of combinations ofthe weighing hoppers in which the weighed value or count of the articles is outside the tolerance range can be minimized and, therefore, the operativity of the combination weighing or counting apparatus can correspondingly be increased.

-<M>-

Claims

1. A combination weighing or counting apparatus which comprises:

a plurality of weighing hoppers (10) to which articles (M) are supplied; acombination calculating means (37) for performing a combinational calculation of weighed values or counts of the articles (M) within those weighing hoppers and for selecting one of combinations of the weighing hoppers (10) which measure respective weight or counts, a combination ofwMch would be closest to a target value (Tc, Tw) or fall within the tolerance range, said one of the combination being a combination of the weighing hoppers (10) in which the number of the weighing hoppers (10) is minimum; an open/close control means (30) for opening the selected weighing hoppers (10) to allow them to discharge the articles (M) therefrom; and an excludingmeans (39) for excluding the selected weighing hoppers (10) from a subsequent combination calculation.

2. The combination weighing or counting apparatus as claimed in Claim 1, wherein said combination calculating means (37) selects one of the combinations in which the number of weighing heads (WH) is minimum, in the event that a deviation between the combined weight or the combined count and the target value(Tc, Tw) is within a head number priority range which is narrower than the tolerance range, said one of the combinations being a combination in which the deviation is

3. The combination weighing or counting apparatus as claimed in Claim 2, wherein said combination calculating means (37) selects one of combinations in which the deviation is minimum, in the event that the deviation between the combined weight or the combined count and the target value (Tc, Tw) is outside the head number priority range, said one of the combinations being a combination in which the number of weighing heads (WH) is minimum. "

4. A combination weighing or counting apparatus which comprises:

a plurality of weighing hoppers (42) to which articles (M) are supplied; a combination calculating means (57) for perfornfing a combinational calculation of weighed values or counts of the articles within those weighing hoppers (42) and -<2>- for selecting one of combinations of the weighing hoppers (42) which measure respective weight or counts, a combination of which would be closest to a target value (Tc, Tw) or fall within the tolerance range, said one of the combination being a combination of the weighing hoppers (42) in which the number of the weighing hoppers (42) is maximum; an open/close control means (45) for opening the selected weighing hoppers (42) to allow them to discharge the articles (M) therefrom; and an excluding means (59) for excluding the selected weighing hoppers from a subsequent combination calculation.

5. The combination weighing or counting apparatus as claimed in Claim 4, wherein said combination calculating means (57) selects one of the combinations in which the number ofweighing heads (WH) is maximum, in the event that a deviation between the combined weight or the combined count and the target value (Tc, Tw) is within a head number priority range which is narrower than the tolerance range, said one of the combinations being a-combination in which the deviation is minimum.

6. The combination weighing or counting apparatus as claimed in Claim 5, wherein said combination calculating means (57) selects one of combinations in which the deviation is minimum, in the event that the deviation between the combined weight or the combined count and the target value (Tc, Tw) is outside the head number priority range, s6d one of the combinations being a combinafion in which the number of weighing heads (WH) is maximum.

-<D>-