WO1997041410A1

WO1997041410A1 - Combinational weigher-counter apparatus

Info

Publication number: WO1997041410A1
Application number: PCT/GB1996/001031
Authority: WO
Inventors: Robert Bennett
Original assignee: Ishida Co., Ltd.
Priority date: 1996-04-30
Filing date: 1996-04-30
Publication date: 1997-11-06
Also published as: WO1997041411A1

Abstract

A combinational weigher-counter apparatus has a plurality of weighing heads each having a pool hopper (5), a weigh hopper (6) and a load cell (8) for weighing articles held inside the weigh hopper. Combinational calculations are carried out on the basis of outputs from the load cells (8) to select a particular combination of weigh hoppers (6) according to a specified criterion and the articles are discharged from the selected combination of weigh hoppers. Each pool hopper (5) and weigh hopper (6) has a discharge opening (13) provided with a discharge gate (7) formed with a plurality of planar shutter blades (16) which move horizontally within its plane to open and close the discharge opening (13) such that effects of wind caused by the opening and closing of the discharge gates (7) as well as the overall height of the apparatus can be reduced.

Description

COMBINATIONAL WEIGHS-COUNTER APPARATUS

Background of the Invention

This invention relates to a combinational weigher- counter apparatus for weighing articles such as candies and agricultural and marine products by using a plurality of weighing devices and selecting a combination of the articles on the basis of their measured weights such that the total weight or number of the articles in the selected combination will be within an allowable range with respect to a given target value. A typical prior art combinational weigher-counter apparatus may be characterized as comprising a feeder for supplying articles, many weighing heads each having a pool hopper and a weigh hopper, and weighing devices individually associated with the weigh hoppers, and being adapted to calculate combinations of weight values outputted from the weighing devices, to select a particular combination of weigh hoppers which will provide a total weight or a total number within an allowable range and to discharge the articles from the selected hoppers, thereby providing a product having articles with an allowable total weight or an allowable total number of articles. As shown schematically in Fig. 14, each of pool hoppers 5 and weigh hoppers 6 is provided at its bottom with a discharge gate G which can rotate upward and downward around a horizontal axis Pl supported by the hopper such that articles inside the hopper can be discharged, each discharge gate G being driven by a gate driver A associated therewith. When a discharge gate G thus structured is opened or closed, however, the wind by its upward or downward motion is likely to cause the other weigh hoppers 6 to swing, thereby adversely affecting the precision in the measurements of the weights of their contents.

With the discharge gates G thus attached rotatably to the pool hoppers 5 and the weigh hoppers 6 around horizontal axes, furthermore, the weigher-counter apparatus incorporating them becomes unnecessarily tall because there must be enough space left for allowing these gates G to freely swing upward and downward. If a packaging machine is installed under the apparatus for making packages of weighed articles, as frequently done, the total height of the system inclusive of the packaging machine becomes still greater, limiting more severely the choice of a location where such a system can be set.

Summary of the invention It is therefore a general object of this invention to provide a combinational weigher-counter apparatus which can measure weights more accurately and of which the height can be reduced.

It is one of specific objects of this invention to provide such a combinational weigher-counter apparatus of which the accuracy in the measurement of weight is not strongly affected by the opening and closing of the discharge gates.

It is another specific objects of this invention to provide such a combinational weigher-counter apparatus having hoppers of which the gates can be opened and closed more quickly.

It is still another specific object of this invention to provide such a combinational weigher-counter apparatus of which the hoppers can be interchanged easily.

In accordance with the present invention, a combinational weigher-counter apparatus comprises a plurality of weighing heads, each having an upper hopper and a lower hopper placed therebelow, and weighing means for weighing articles inside one of said hoppers; and means for carrying out combinational calculations selectively on the weights or numbers of articles measured by said weighing means, selecting a combination of hoppers according to a specified criterion and based on said combinational calculations and discharging articles from hoppers of said combination; each of said upper and lower hoppers having a discharge opening and a discharge gate, at least one of said discharge gates moving within a plane to close and open said discharge opening and having a gate driving means for causing said discharge gate to move within said plane.

With a weigher-counter apparatus thus structured, effects of the wind caused by the opening and closing of the discharge gates can be reduced because the discharge gates are adapted to move within their own planes. Thus, not only can the accuracy of measurement be improved but the total height of the weigher-counter apparatus can be reduced. Preferably, each discharge gate moves within a plane to close and open said discharge opening and has a gate driving means for causing said discharge gate to move within said plane.

According to a preferred embodiment, the discharge gate is formed with a set of planar shutter blades, each of which is attached to a blade-supporting shaft supported rotatably by the hopper. The gate driver means include an endless motion-communicating member such as a belt passed over these blade-supporting shafts and a means for causing this member to move so as to cause the blade-supporting shafts to rotate through the motion-communicating member. Alternatively, the gate driver means may comprise a link mechanism for causing the blade-supporting shafts to rotate and a driver means, such as a motor, serving to drive the link mechanism.

According to still another preferred embodiment, the weighing heads are arranged in a circle and each discharge gate is formed with a coplanar pair of planar doors which are adapted to move in their plane radially, with respect to the circular distribution of the weighing heads, either

each other of away from each other so as to respectively close or open the discharge opening of the hopper.

It is further preferred to arrange the discharge gates of different weighing heads such that the gates of mutually adjacent weighing heads are, and move, in different planes so as not to collide each other as they open and close. With the planes of motion of the discharge gates thus arranged, the weighing heads can be arranged closer to one another and hence the overall size of the weigher-counter apparatus can also be reduced.

Brief Description of the Drawings

The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings:

Fig. 1 is a schematic front view of a combinational weigher-counter apparatus according to a first embodiment of this invention;

Fig. 2 is a schematic plan view of the apparatus of Fig. 1;

Fig. 3 is a horizontal side view of a portion of the same apparatus with some components removed for the purpose of description and some components shown sectionally;

Fig. 4 is a plan view of the discharge gate of a weigh hopper and its gate driving means of the same apparatus;

Fig. 5 is a plan view of the discharge gate of Fig. 4;

Fig. 6 is a side horizontal view of the gate driving means with some components shown sectionally; Fig. 7 is a portion of Fig. 4 shown enlarged and more in detail;

Fig. 8 is a horizontal view of three mutually adjacent ones of the weigh hoppers; Fig. 9 is a plan view of another discharge gate of a pool hopper and its gate driving means according to a second embodiment of this invention;

Fig. 10 is a vertical sectional view of the discharge gate and the gate driving means of Fig. 9;

Fig. 11 is a plan view of a portion of another combinational weigher-counter apparatus according to a third embodiment of this invention for showing the arrangement of its weighing heads; Fig. 12 is a plan view of a portion of the apparatus of Fig. 11 for showing the structure of its gate driving means;

Fig. 13 is a partially sectional horizontal view of a portion of the apparatus of Fig. 11 with some components shown sectionally; and

Fig. 14 is a schematic horizontal view of a portion of a prior art combinational weigher-counter apparatus showing arrangement of its pool and weigh hoppers and means for moving their gates. Throughout herein, some of the components which are substantially identical although they are components of different apparatus according to different embodiments of this invention are indicated by the same numerals in different figures and are not repeatedly described in the specification.

Detailed Description of the Invention

The invention is explained next with reference to examples. Fig. 1 is a schematic front view of a combinational weigher-counter apparatus according to a first embodiment of this invention, having a flat cone-shaped dispersion table 3 at the center at an elevated position directly under a supply chute 2 provided opposite article-discharging end of a supply conveyor 1 and a plurality of weighing heads WH disposed in a circle with the dispersion table 3 at the center. Each weighing head WH has a radial trough 4 extended radially from the table 3, a pool hopper 5 disposed at the outer end of the radial trough 4, a weigh hopper 6 disposed therebelow and a load cell 8 serving as weighing means connected to the weigh hopper 6. Each hopper (that is, each of the pool and weigh hoppers 5, 6) has a discharge gate 7 adapted to move within its plane to open and close its discharge opening. Further therebelow, there are a collection chute 9 and a discharge chute 10, and a packaging machine PM is disposed below the apparatus supported by a base B. Articles M, transported by the supply conveyor 1, are dropped approximately at the center of the dispersion table 3 through the supply chute 2 and are dispersed, by the vibrations of the dispersion table 3, into the plurality of radial troughs 4. The articles M are further sent into the plurality of pool hoppers 5 by the vibrations of the radial troughs 4. After they are temporarily stored therein in accordance with the weighing operation, the discharge gate 7 at the bottom of each pool hopper 5 is opened and the articles M are dropped into the plurality of weigh hoppers 6. The load cells 8 measure the weights of the articles M dropped into the individual weigh hoppers 6 and output weight signals indicative of the measured weights. Combinational calculations are carried out by a control means (symbolically shown at 100 in Fig. 1) of a known type on the basis of these weight signals, and those of the weigh hoppers 6 providing a total weight, which falls within a specified range with respect to a specified target weight, are selected. The articles M inside the selected weigh hoppers 6 are dropped into the collection chute 9, as the discharge gates 7 at the bottoms of the selected weigh hoppers 6 are opened, and discharged into the discharge chute 10. The discharged articles M are made into a package by the packaging machine PM, appearing as a packaged product having the target weight. As shown in Fig. 2, the plurality of weighing heads WH are arranged in a circle, when seen from above. As shown in Fig. 3, each discharge gate 7 is driven by a gate driving means 18 (to be described in detail below) to move in a horizontal plane to open or close the discharge opening (indicated by numeral 13) of the associated hopper 5 or 6. Since the pool hoppers 5 and the weigh hoppers 6 are substantially identical in structure, only one of the weigh hoppers 6 will be described in detail next with reference to Figs. 4-8.

As shown in Fig. 4, the weigh hopper 6 has a tubular main body 11 with a quadrangular cross-sectional shape, having an approximately quadrangular discharge opening 13. As shown in Fig. 5, the discharge gate 7 is formed with a plate divided into four parts (referred to as "the shutter blades") 16 and four blade-supporting shafts 19 to which the four shutter blades 16 are individually attached. Each shutter blade 16 is approximately triangular in shape, as shown in Fig. 5, and can rotate in a horizontal plane between an open position and a closed position around the axis of the blade-supporting shaft 19 to which it is attached. In Fig. 5, solid lines show the closed positions, at which the four shutter blades 16 engage one another so as to together completely block the discharge opening 13 of the main body 11, while broken lines show their open positions which are separate from the discharge opening 13. As shown in Fig. 6, there is a holder case 14 attached to the outside of the main body 11 of the weigh hopper 6, rotatably supporting the blade-supporting shafts 19 each by means of a pair of upper and lower bearings BI. The holder case 14 consists of a lower case 14a attached to the main body 11 and an upper case 14b attached to the lower case 14a by screws (not shown) , the upper and lower ones of the pairs of bearings BI being respectively supported separately by the upper and lower cases 14b and 14a. The lower end of each blade-supporting shaft 19 protrudes downward from the lower case 14a, having an end piece 15 attached thereto. The shutter blades 16 are each screwed to the corresponding one of the blade-supporting shafts 19, while being in contact with these end pieces 15. A washer 17 is inserted between each end piece 15 and the inner ring of the corresponding lower bearing BI. The shutter blades 16 are disposed near the bottom edges of the main body 11 such that, when they are rotated to discharge articles thereon, the bottom edges of the main body 11 nearly sweeps their upper surfaces. Sticky matters stuck on the blade surfaces can be removed by this swiping motion of the shutter blades 16. Fig. 8 shows more in detail that the shutter blades 16 of mutually adjacent weighing heads WH are at slightly different heights such that the shutter blades 16 belonging to different weighing heads WH will not collide with each other when they are opened. As a result, mutually adjacent pairs of the weighing heads WH can be brought closer together, and the overall size of the apparatus can be reduced..

The gate driving means 18, briefly referred to above with reference to Fig. 3, is described next more in detail. As shown in Fig. 6, each blade-supporting shaft 19 is provided with a toothed follower pulley 20 affixed between the pair of bearings BI. A tooth belt 21, which is a kind of endless conveyor belt, is passed around the blade-supporting shafts 19, engaging with their follower pulleys 20 as shown in Fig. 4. A drive shaft 26 is also supported rotatably by the holder case 14 through a pair of bearings B2 as shown in Fig. 6. A toothed drive pulley 22 is attached to this drive shaft 26 at the same height as the follower pulleys 20, and idler rollers 23 are also rotatably supported by the holder case 14 as shown in Fig. 3 through shafts and bearings (not shown) for maintaining the driver pulley 22 and the follower pulleys 20 in an engaged condition with an appropriate tension maintained in the belt 21.

There is a lever 25 attached to an upper part of the drive shaft 26 with a spacer 27 separating it from the holder case 14. One end of the lever 25 is branched into two protrusions, or branches, 35 and 36 forming an indentation, or a groove, 37 therebetween, as shown more clearly in Fig. 7. The blade-supporting shafts 19, the drive shaft 26, the bearings BI and B2, the pulleys 20 and 22 and the belt 21 are all enclosed inside the holder case 14 and protected against dust.

A rotary air cylinder 30, serving as means for driving the tooth belt 21, is supported, as shown in Fig. 3, through a bracket BK by a frame F attached to the base B

(shown in Fig. 1). As shown in Fig. 4, the cylinder 30 is disposed such that its rotary shaft 31 is parallel to the drive shaft 26 but is separate therefrom, or eccentric with respect thereto. An elongated member (herein referred to as the arm) 32 is attached to the rotary shaft 31, extending radially therefrom and having a roller 33 rotatably attached to its end. The shaft of this roller 33 is parallel to the rotary shaft 31 but is separate therefrom, having a specified distance therebetween, such that the roller 33 will move into the groove 37 at the branched end of the lever 25 as the arm 32 rotates around the rotary shaft 31, coming into a motion- communicating relationship with the lever 25 and causing the lever 25 to rotate around the drive shaft 26. Explained more in detail with reference to Fig. 7, the cylinder 30 is designed such that the roller 33 thereon will undergo a reciprocating rotary motion between two angular limits Al and A4 separated by 270 degrees. The right-hand angular limit position Al corresponds to the opened position and the left- hand angular limit position A4 corresponds to the closed position of the corresponding shutter blades 16.

As shown in Fig. 3, the load cell 8 has a fixed part 8a and a mobile (or free) load-receiving part 8b connected to each other by a pair of upper and lower horizontally extending beams 8c. The fixed part 8a is affixed to the aforementioned frame F, and the holder case 14 being supported through a supporting member 38 by a- supporting block 39 which is attached to the free part 8b, such that the total weight of the weigh hopper 6, the holder case 14, the lever 25 and the spacer 27 serve as a load on the fixed part 8a of the load cell 8. The holder case 14 of a pool hopper 5 is supported through a similar supporting member by the aforementioned bracket BK.

It should be clear from the description above that the weight of the gate-opening means is not applied to the load call 8 during the weight-measuring process, the gate (and the discharge opening 13) being opened and closed by a horizontal movement of the roller 33 into or out of the groove 37 in the lever 25.

Next, the operation of the discharge gate 7 as described above will be explained more in detail.

Let us assume that the shutter blades 16 are in the open positions shown by dotted lines in Fig. 5, with the roller 33 at the right-hand angular limit position Al shown in Fig. 7. As the cylinder 30 is activated to rotate its shaft 31 in the clockwise direction, the arm 32 is rotated and the roller 33, reaching the angular position indicated by symbol A2 in Fig. 7, moves into the groove 37 between the branches 35 and 36 of the lever 25. Thereafter, the roller 33 pushes the inner rim on one after the other of the branches 35 and 36 to cause the lever 17 to rotate in the counter-clockwise direction (from the position indicated by solid lines to the position indicated by dotted lines in Fig. 7) . This causes the drive shaft 26 connected to the lever 17, as well as the driver pulley 22 attached to the drive shaft 26, to both rotate in the same counter-clockwise direction with respect to Fig. 4. The counter-clockwise rotation of the driver pulley 22 is communicated through the belt 21 and all four follower pulleys 20 are rotated, causing the shutter blades 16 to close the discharge opening 13, as shown by solid lines in Fig. 5. The roller 33, after leaving the groove 37 at its angular position indicated by A3, continues to rotate in the clockwise direction until it reaches and stops at its left-hand angular limit position A4.

In summary, since the shutter blades 16 are adapted to move in a plane (indicated by letter P in Fig. 3), they do not cause any strong wind when they open or close. Consequently, the weigh hoppers 6 according to this invention are not affected by the opening or closing operations of the other hoppers and hence the accuracy of their measurements is not compromised. Since the shutter blades 16 according to this invention do not require a large space for their rotary motion as they are opened or closed, the discharge gates 7 can be made lower and hence the apparatus as a whole can be made less tall. Next, another gate driving means 18A according to a second embodiment of this invention is described with reference to Figs. 9 and 10. The gate driving means 18A according to this embodiment is characterized as using a linking mechanism for a discharge gate 7A of the so-called iris type with three planar shutter blades 46. Each of the shutter blades 46 is attached to a support member 56, 58 or 60. Each of these support members 56, 58 and 60 is rotatably supported by and is adapted to rotate around respective one of pivot pins 41 which are supported by a flange 12 of the main body 11 of the hopper. In Fig. 9, the closed positions and open positions of the blades 46 are shown respectively by solid and broken lines.

One of the support members (indicated by 58 in Fig. 9) is in the form of a double-bell crank lever, having a pair of short leg parts 47 and 48 and a longer middle leg part 49, the other two support members 56 and 60 each having a single leg part 51 or 52. The middle leg part 49 of the double-bell crank lever 58 is connected rotatably to one end of a first link 61, the other end of which is connected rotatably to a drive crank 64. The two short leg parts 47 and 48 are rotatably connected to one end respectively of a second link 62 and a third link 63. The other ends of the second and third links 62 and 63 are connected respectively to the single leg parts 51 and 52 of the other support members 56 and 60. The drive crank 64 is connected to the rotary shaft 31 of a driver 30 (such as a rotary air cylinder) so as to undergo a reciprocating angular motion within a specified angular range. The weigh hopper 6 is supported by a load cell 8 through a bracket-shaped arm member 59 as shown in Fig. 10. The operation of the discharge gate 7A described above will be explained next. First, let us assume that the plate parts 46 are initially in the closed positions shown by solid lines in Fig. 9. As the driver 30 is activated and its drive shaft 31 rotates the drive crank 64 by 180 degrees in the clockwise direction, the first link 61 causes the double- bell crank lever 58 to rotate in the clockwise direction. This rotary motion is communicated through the second and third links 62 and 63 to the other support members 56 and 60, thereby causing all three shutter blades 46 to rotate within a horizontal plane from their closed positions to the open positions indicated by the dotted lines in Fig. 9. If the driver 30 next rotates by 180 degrees in the counter-clockwise direction, the shutter blades 46 move back from their open positions back to the closed positions. A still another combinational weigher-counter apparatus incorporating a gate driving means 18B according to a third embodiment of this invention is explained next with reference to Figs. 11-13.

As shown in Fig. 11 in part, the plurality of weighing heads WH, each having a pool hopper 5 and a weigh hopper 6 as described above, are also arranged in a circle, but the discharge gate 7B for opening and closing the discharge opening of each of these hoppers 5 and 6 has only two planar doors 76. Each door 76 is approximately rectangular and they are adapted to move horizontally away from or towards each other in the radial direction with respect to the circle in which the group of weighing heads WH is disposed, as shown in Fig. 12. In Fig. 12, solid lines show the two doors 76 in the closed positions and broken lines show them at their open positions. In summary, since the doors 76 of each weighing head WH move only radially (and not in the circumferential directions at all) , they can be opened and closed without hitting any parts of the adjoining weighing heads WH. Thus, the plurality of weighing heads WH can be arranged with only a very small interval between each mutually adjacent pair of them, and hence a compact combinational weigher-counter apparatus can be designed.

Since the pool hoppers 5 and the weigh hoppers 6 are structured alike also according to this embodiment, the structure of a weigh hopper 6 will be explained next more in detail.

As shown in Fig. 12, each door 76 of the weigh hopper 6 is attached through a connector 80 to a tooth belt 21. A holder case 84 is attached to the cylindrical main body 11 as shown in both Figs. 12 and 13, and idler shafts 86 (only one shown in Fig. 13) and a drive shaft 26 are rotatably supported by the holder case 84 each through a pair of upper and lower bearings B3 and B2, respectively. An idler pulley 23 is attached to each of the idler shafts 86 and a drive tooth pulley 22 is attached to the drive shaft 26. The idler pulleys 23, the tooth belt 21 and the drive pulley 22 are all covered by the holder case 84. The motion-communicating mechanism for communicating power from a driver (such as a motor 30) to the drive shaft 26 may be as described above with reference to the first embodiment of this invention. Next the operation of the discharge gate 7B according to the third embodiment of the invention will be described more in detail. Let us assume that the doors 76 are initially in the closed positions as shown by solid lines in Fig. 12. The cylinder 30 is then activated to cause the drive pulley 22 to rotate in the counter-clockwise direction, thereby moving the belt 21 in the same direction, as well as the connectors 80 therealong. As a result, each door 76 is caused to slide away from each other linearly (or radially with respect to the circular positions of the weighing heads WH as shown in Fig. 11) and horizontally within its own plane as indicated by arrows Yl and Y2 in Fig. 12 until they reach their open positions indicated by the broken lines. If the motor 30 is activated next to cause the drive pulley 22 to rotate in the reverse direction, the doors 76 move towards each other in the same plane until they come to their closed positions indicated by solid lines in Fig. 12.

The invention has been described above with reference to only a limited number of embodiments, but they are intended to be illustrative, not limitative. Many modifications and variations are possible within the scope of the invention. For example, the shutter blades 16 in the first embodiment of the invention described above with reference to Figs. 1-5 need not use a tooth belt or toothed pulleys. Use may equally well be made of a chain and sprockets of known kinds or a series of sequentially engaging gears as power-communicating means. As another example, although weighing heads each with a pool hopper and a weigh hopper were disclosed in all of the described embodiments, a so-called booster hopper may be added below the weigh hopper for temporarily storing the articles which have been weighed in the weigh hopper such that the batches of articles in such booster hoppers can also participate in the combinational calculations. As a further variation of the above, pool hoppers may be totally dispensed with, by forming each weighing head only with a weigh hopper and a booster hopper. In the latter case, the weighing means (such as indicated by numeral 8) is connected only to the weigh hopper 6 which is the upper one of the two hoppers of each weighing head. As still another example, the present invention is applicable to the kind of combinational weigher-counter apparatus adapted to first divide weight values of the batches of articles outputted from the weighing means by a specified unit weight to obtain numbers of articles in the batches and to then carry out combinational calculations in terms of these numbers, instead of directly combining weight values as outputted from the weighing means. Finally, it goes without saying that the present invention is applicable to combinational weigher-counter apparatus of the so-called in¬ line type with individual weighing heads arranged on a straight line, rather than in a circle.

In summary, planar discharge gates of the present invention open and close by moving in a plane, and hence the effects of wind caused by such motion of discharge gates of the hoppers can be kept to a minimum. As a result, the accuracy of measurements can be improved and the height of the discharge gates and hence also the total height of the apparatus incorporating such discharge gates can be reduced. In addition to the above, there are several additional advantages which can be gained by the present invention. Firstly, because discharge gates according to this invention are adapted to slide horizontally sideways, objects which have been stuck thereon can be removed.as the planar shutter blades constituting the gates are swung sideways.

Secondly, it is not necessary, according to this invention, to replace the entire hopper when different contact surfaces are required such as plastic or embossed surfaces. If each main body 11 of the hoppers 5 and 6 is designed as a so-called push-fit tube adapted to be removably engageable with the corresponding holder case 14 by merely pushing it downward thereon, simple replacements of these push-fit tubes will easily serve the purpose. Thirdly, the weigh and pool hoppers on a system according to this invention are easily interchangeable by merely changing these push-fit tubes while these hoppers on prior art weighing machines could not be freely interchangeable. Fourthly, so-called iris mechanisms, as shown in Fig. 4, can operate much more quickly to open and close the hoppers, leading to faster product handling and therefore a faster machine having the same number of heads.

Claims

1. A combinational weigher-counter apparatus comprising: a plurality of weighing heads each having an upper hopper, a lower hopper which is disposed below said upper hopper and a weighing means for weighing articles inside one of said hoppers; and means for carrying out combinational calculations selectively on the weights or numbers of articles measured by said weighing means, selecting a combination of hoppers according to a specified criterion and based on said combinational calculations and discharging articles from hoppers of said combination; each of said upper and lower hoppers having a discharge opening and a discharge gate, at least one of said discharge gates moving within a plane to close and open said discharge opening and having a gate driving means for causing said discharge gate to move wit-hin said plane.

2. The combinational weigher-counter apparatus of claim 1 wherein said discharge gate comprises a plural n-number of planar shutter blades lying in said plane.

3. The combinational weigher-counter apparatus of claim 2 wherein said discharge gate further comprises a plural n- number of rotatable blade-supporting shafts, each of said shutter blades being affixed to associated one of said blade- supporting shafts, and wherein said gate driving means includes an endless motion-communicating means stretched over said plurality of blade-supporting shafts for causing said plurality of blade-supporting shafts to rotate and a driver means for moving said endless motion-communicating means.

4. The combinational weigher-counter apparatus of claim 2 wherein said discharge gate further comprises a plural n- number of rotatable blade-supporting shafts, each of said shutter blades being affixed to associated one of said blade- supporting shafts, and wherein said gate driving means includes a link mechanism for causing said n-number of blade- supporting shafts to rotate and a driver means for moving said link mechanism.

5. The combinational weigher-counter apparatus of any of claims 2 to 4, wherein the planes associated with each mutually adjacent pair of said weighing heads are parallel to but removed from each other, wherein the shutter blades associated with different ones of said weighing heads do not mutually collide while opening.

6. The combinational weigher-counter apparatus of claim 1 wherein said weighing heads are arranged horizontally in a circle, said discharge gate has a pair of two planar doors, said gate driving means includes an endless motion- communicating means for causing said two doors to move radially with respect to said circle towards and away from each other to close and open said discharge opening and a driver means for moving said endless motion-communicating means.