Dispersing feed device and combination weighing device comprised of at least two elastic units inclined in different directions with different natural frequencies that can vary a feed direction of articles thereon by changing the driven vibration frequency

The present invention provides a dispersing feed device including: a dispersion table adapted to receive articles supplied from above and to feed the articles to multiple sections on the periphery of the dispersion table; a first elastic unit inclinedly connected to the dispersion table, the first elastic unit having a first natural frequency; a second elastic unit connected to the dispersion table inclinedly in a direction different from the inclination direction of the first elastic unit, the second elastic unit having a second natural frequency which is different from the first natural frequency; and at least one vibrating source adapted to vibrate the dispersion table through the first and second elastic units.

TECHNICAL FIELD

The present invention relates to a dispersing feed device which disperses articles to feed it to multiple sections on the periphery of the dispersing feed device, and the present invention relates to a combination weighing device having the dispersing feed device.

BACKGROUND ART

Patent Literature 1, JP H06-074814 A, discloses a combination weighing device as an example. The combination weighing device includes a dispersion feed unit which has a conical dispersion table, multiple radial feeders each of which has a trough extending radially from a periphery of the dispersion table, multiple pool hoppers each of which is arranged below a distal end of the trough, multiple weighing hoppers each of which is arranged below the pool hopper, and a merging chute which is arranged below the weighing hoppers. The articles supplied from above to the dispersion table are dispersed in a circumferential direction of the table to be fed toward its outside in a radial direction, causing the articles to fall off the table to be provided into the troughs of the radial feeders. In each trough, the articles are fed toward the outside of the trough in a radial direction by the radial feeder, causing the articles to fall off the trough to be provided into the weighing hopper through the pool hopper. The articles placed in the weighing hoppers are weighed. A computer combines the weighing values of the articles in the weighing hoppers to work out multiple combinations of the weighing values which are also called “combination weighing values”. Then, the computer selects one combination from all of the combinations, which is closest to a preset weight. The articles fall off multiple weighing hoppers corresponding to the selected combination to be provided into the merging chute.

This kind of combination weighing device is required to properly supply the articles into all the weighing hoppers in order to work out the combination weighing value which is closest to a preset weight.

Patent Literature 2, WO 2009/078273, discloses a technique for properly supplying articles into pool hoppers and weighing hoppers by use of radial feeders. Each of radial feeders disclosed in Patent Literature 2 has a trough which is connected on its bottom surface to a first lead spring and a second leaf spring. These leaf springs have different natural frequencies. The first leaf spring is arranged to extend obliquely upward in a direction opposite to a feed direction of the articles to the pool hopper, and the second leaf spring is arranged to extend obliquely upward in the feed direction. When a vibrating source generates a vibration having a frequency which is near the natural frequency of the first leaf spring, its upper end oscillates obliquely upward in the feed direction around its lower end, causing the oscillation to be transmitted to the bottom surface of the trough. This causes the articles on the trough to be fed toward the pool hopper. In contrast, when the vibrating source generates a vibration having another frequency which is near the natural frequency of the second leaf spring, its upper end oscillates obliquely upward in the opposite direction around its lower end. This oscillation is transmitted to the bottom surface of the trough, causing the articles on the trough to be fed back to the opposite side of the pool hopper.

According to the technique disclosed in Patent Literature 2, by controlling a frequency of the vibrating source to move the articles forward and backward on the trough, and to adjust a feed rate of the articles in the feed direction, the articles can be properly conveyed by the radial feeders.

Patent Literature 1: JP H06-074814 A

In the conventional combination weighing device, the dispersion table of the dispersion feed unit typically discharges the articles provided from one upper place to multiple radial feeders. The conventional dispersion feed unit can control a single dispersion table only to perform a single movement, making it difficult to precisely control a discharge of the articles to multiple discharge sections. In particular, when a dispersion table in the shape of a semicircle in planar view is used, the articles on the dispersion table tend to concentrate on one side in its circumferential direction and to be insufficient on another side in the circumferential direction. This can incur a quantitative deficiency or excess of the articles in some discharge sections. The conventional solution for this problem is only to adjust a position of the one upper place for providing the articles to the dispersion table.

The above technique of Patent Literature 2 for making a feed of articles more appropriate have applied only to a simple type of radial feeders which feed the articles supplied from one place to one discharge section, not yet to more complicate types of feeders or tables which is adapted to feed the articles supplied from one or more places to multiple discharge sections, because correspondence relationships between one or more supply places and multiple discharge sections are complicated.

A purpose of the invention is to enable articles to be properly supplied from a dispersion table to multiple sections.

SUMMARY OF THE INVENTION

For this purpose, a dispersing feed device of the invention includes:

a dispersion table adapted to receive articles supplied from above and to feed the articles to multiple sections on a periphery of the dispersion table;

a first elastic unit inclinedly connected to the dispersion table, the first elastic unit having a first natural frequency;

a second elastic unit connected to the dispersion table inclinedly in a direction different from the inclination direction of the first elastic unit, the second elastic unit having a second natural frequency which is different from the first natural frequency; and

at least one vibrating source adapted to vibrate the dispersion table through the first and second elastic units.

According to the dispersing feed device of the invention, when the vibrating source generates a vibration in a frequency being equal to or near the first natural frequency, amplitude of the vibration of the first elastic unit increases to enable a feed rate of the articles on the dispersion table in a direction corresponding to an obliquity of the first elastic unit to increase. Also, when the vibrating source generates a vibration in a frequency being equal to or near the second natural frequency, amplitude of the vibration of the second elastic unit increases to enable a feed rate of the articles on the dispersion table in a direction corresponding to an obliquity of the second elastic unit to increase. Accordingly, adjusting the frequency of the vibration generated by the vibrating source enables a feed direction and a feed rate of the articles on the dispersion table to be properly adjusted, inhibiting the articles from concentrating one part and being insufficient on another part on the dispersion table. This enables the articles on the dispersion table to be properly supplied to multiple sections on the periphery of the table.

When the dispersing feed device of the invention includes multiple elastic unit groups each having the first and second elastic units, the groups may be connected to the dispersion table at positions different from each other in a circumferential direction thereof. This enables loads on the elastic unit groups from the dispersion table to be dispersed, enhancing permanence of the first and second elastic units.

In the dispersing feed device of the invention, when the dispersion table has a circular or arc-like periphery in planar view, the multiple elastic unit groups may be arranged at different angles in planar view. This enables directions of vibrations acted on the dispersion table to vary with position in the circumferential direction of the table. This allows the articles on the dispersion table to be fed in torsion direction in planar view, enabling unevenness of density of the articles on the dispersion table to be effectively decreased.

When the dispersing feed device of the invention includes multiple vibrating sources, the dispersing feed device may further include at least one drive unit adapted to drive the vibrating sources at different vibration frequencies. In this case, if the multiple vibrating sources are driven in different frequencies, amplitude of the vibrations of the first and the second elastic units can be adjusted individually. Therefore, a direction and amplitude of a composite vibration transmitted from each elastic unit group to the dispersion table can be more precisely adjusted, enabling the articles to be fed from a certain position on the dispersion table to desired position on the periphery of the table, which allows feed amount of the articles to each section of the periphery of the dispersion table to be precisely adjusted.

When the dispersing feed device of the invention includes a counterweight connected to the dispersion table through the first and second elastic units which are connected in series with each other between the dispersion table and the counterweight, an upper end portion of the first elastic unit may be connected to the dispersion table, an upper end portion of the second elastic unit may be connected to the counterweight, and lower end portions of the first and second elastic units may be connected to each other. In this case, the lower end portion of the first elastic unit (which extends obliquely downward at one angle from the dispersion table) and the lower end portion of the second elastic unit (which extends obliquely downward at another angle from the counterweight) are serially connected between the dispersion and the counterweight. This allows the counterweight, the dispersion table, the first elastic unit and the second elastic unit to be arranged compactly in a vertical direction as a whole, unlike in the case that an upper end portion of the second elastic unit extending obliquely upward from the counterweight is connected to a lower end portion of the first elastic unit.

When the dispersing feed device of the invention includes a connecting member connecting the first and second elastic units to each other, the connecting member may have a horizontal portion arranged horizontally and a rising portion extending upward from the horizontal portion. Also, in this case, the first elastic unit may extend obliquely downward from a connection with the dispersion table toward one side of the circumferential direction and may be connected on its lower end portion to the rising portion. Further, in this case, the second elastic unit may extend obliquely downward from a connection with the counterweight toward the other side of the circumferential direction and may be connected on its lower end portion to the horizontal portion. This allows the first elastic unit which extends obliquely downward from the connection with the dispersion table toward one side of the circumferential direction, and the second elastic unit which extends obliquely downward from the connection with the counterweigh toward the other side of the circumferential direction to be connected compactly in the vertical and circumferential directions through the connecting member having the horizontal portion and the rising portion.

The dispersing feed device of the invention may further include a dispersion unevenness detecting unit adapted to detect unevenness of dispersion of the articles on the dispersion table, and a control unit adapted to control a vibration frequency of a vibration generated by the at least one vibrating source based on dispersion unevenness detected by the dispersion unevenness detecting unit. This enables the feed direction and feed rate of the articles on the dispersion table to be adjusted to inhibit the articles from concentrating one part and being insufficient on another part on the dispersion table, by controlling the frequency of the vibration generated by the vibrating source to control the amplitudes of the vibrations of the first and second elastic units.

A combination weighing device of the invention includes:

the above dispersing feed device;

multiple weighing hoppers arrayed in the circumferential direction around the dispersion table, the weighing hoppers each adapted to hold the articles supplied from the dispersion table;

weight measuring units adapted to measure a weight of the articles held by each of the weighing hoppers;

a calculation unit adapted to calculate a target value of feed amount of the articles to each of the weighing hoppers based on the weights measured by the weight measuring units; and

a control unit adapted to control a vibration frequency of a vibration generated by the at least one vibrating source based on the target value calculated by the calculation unit.

The combination weighing device of the invention allows the feed direction and feed rate of the articles on the dispersion table to be adjusted to make feed amount of the articles to each weighing hopper closer to a targeted value, by controlling the frequency of the vibration generated by the vibrating source to control the amplitudes of the vibrations of the first and second elastic units. This causes an appropriate amount of articles to be supplied to each weighing hopper, enhancing the accuracy of combination weighing.

The combination weighing device of the invention may further include a dispersion unevenness detecting unit adapted to detect unevenness of dispersion of the articles on the dispersion table. Also, in this case, the control section may be adapted to control the vibration frequency of the vibration generated by the at least one vibrating source based on the target value calculated by the calculation unit and the unevenness of dispersion of the articles detected by the dispersion unevenness detecting unit. This inhibits unevenness of dispersion of the articles on the dispersion table and allows feed amount of the articles from the dispersion table to each weighing hopper to be precisely adjusted to the targeted value.

Effects of the Invention

According to the invention, the feed direction and feed rate of the articles on the dispersion table can be properly adjusted, by adjusting the frequency of the vibration generated by the vibrating source. This inhibits unevenness of dispersion of the articles on the dispersion table and allows the articles to be fed to multiple sections on the periphery of the dispersion table.

EMBODIMENTS OF THE INVENTION

With reference to the accompanying drawings, embodiments of the present invention will be described below.

Combination Weighing Device

FIG. 1andFIG. 2show a combination weighing device (hereinafter, simply referred to as “weighing device”)1according to one embodiment of the present invention.

As shown inFIG. 1andFIG. 2, the weighing device1includes: a dispersing feed element2having a dispersing feed device described later; an annular delivery element3which surrounds the dispersing feed element2; a plurality of pool hoppers8disposed below an outer peripheral portion of the delivery element3; a plurality of weighing hoppers10disposed below the pool hoppers8; a merging chute14disposed below the weighing hoppers10; and a frame16which supports these constitutional elements.

The dispersing feed element2is formed of one or a plurality of dispersing feed devices. For example, in the first embodiment described later, the dispersing feed element2is formed by combining two dispersing feed devices20(20a,20b), while in a second embodiment described later, the dispersing feed element2is formed of only one dispersing feed device120. However, the dispersing feed element2may be formed by combining three or more dispersing feed devices. The specific structure of the dispersing feed device is described for respective embodiments later. Regardless of the number of dispersing feed devices, the dispersing feed element2includes one conical dispersion table122(seeFIG. 11) or a plurality of dispersion tables22formed to be split in a circumferential direction which form a conical shape as a whole. The dispersing feed element2includes a vibration mechanism30which applies vibrations to the dispersion table.

The delivery element3includes a plurality of radial feeders4arranged in a circumferential direction92of the dispersion table22(seeFIG. 2). The radial feeder4includes: a trough which extends radially from a periphery of the dispersion table22; and a conveying unit6which conveys articles on the trough5to the pool hopper8. The conveying unit6is, for example, a vibrator which moves the articles on the trough5by applying vibrations to the trough5. However, a mechanism for conveying the articles on the trough5is not limited to a vibration-applying-type mechanism and, for example, a rotary-drive-type conveying unit which includes a rotationally drivable coil unit on the trough5may be provided in place of the vibration-applying-type conveying unit6.

The pool hopper8and the weighing hopper10are provided for every radial feeder4, and are disposed below an outer end portion of the trough5of the corresponding radial feeder4in the radial direction94(seeFIG. 2).

With the weighing device1having the above-mentioned configuration, articles (object whose weight is to be measured) having a weight near a set weight can be acquired through following operations.

First, articles are dropped from the supply conveyers18(18a,18b) disposed above the dispersion table22and supplied onto the dispersion table22. The articles on the dispersion table22are fed to the outside in a radial direction due to inclination of an upper surface of the dispersion table22while being distributed in a circumferential direction due to vibrations of the dispersion table22generated by the vibration mechanism30, and the articles are dropped and supplied to the troughs5of the radial feeders4.

The articles on each trough5are conveyed toward the outside in the radial direction94(seeFIG. 2) by the radial feeder4, and are dropped and supplied to the pool hopper8. Subsequently, the articles are temporarily held by the pool hopper8and, thereafter, the articles are dropped and supplied to the weighing hopper10.

Weights of the articles stored in the plurality of weighing hoppers10are measured by weight measuring sensors12(seeFIG. 10). The weight measuring sensor12is formed of a load cell provided for every weighing hopper10, for example. Measured weight values of the weight measuring sensors12are combined with each other by a control unit102of a controller100described later (seeFIG. 10) to acquire a plurality of combined measured weight values. Then, the combination which is closest to the set weight is selected by the control unit102among the combined measured weight values, and gates (not shown in the drawing) of the plurality of weighing hoppers10corresponding to the selected combination are opened. The articles in the plurality of weighing hoppers10whose gates are opened are dropped and supplied to the merging chute14. Accordingly, the articles having a weight near the set value can be obtained.

Dispersing Feed Device

Hereinafter, the specific configuration of the dispersing feed device is described for every embodiment.

First Embodiment

As show inFIG. 1andFIG. 2, in the first embodiment, two dispersing feed devices20(20a,20b) having the same structure are mounted on the weighing device1. Each dispersing feed device20a,20bincludes a dispersion table22having a semicircular shape in planar view. Two dispersing feed devices20a,20bare disposed adjacently to each other such that these dispersion tables22are combined in an approximately conical shape.

As shown inFIG. 1, above the dispersion tables22of the respective dispersing feed devices20a,20b, the supply conveyers18a,18bcorresponding to the dispersion tables22are disposed individually. With such a configuration, it is possible to supply articles of different kinds to two dispersion tables22. However, articles of the same kind may be supplied to two dispersion tables22from one supply conveyer18. In any cases, articles are supplied to the respective dispersion tables22from one place above the dispersion tables22. However, articles may be supplied to the dispersion tables22from a plurality of places above the dispersion tables22.

The vibration mechanism30is provided in every dispersion table22. With such a configuration, vibrations are applied to two dispersion tables22individually by the vibration mechanism30corresponding to the dispersion tables22. However, common vibrations may be applied to two dispersion tables22by the common vibration mechanism30.

A specific example of the structure of the dispersing feed device20is described with reference toFIG. 3toFIG. 8.

As shown inFIG. 3toFIG. 6, the dispersing feed device20includes the single dispersion table22. The dispersion table22includes: a table body23; and table base26which supports the table body23by way of connecting units28.

The table body23is formed of a sheet of plate-like member having a semi-conical shape, for example. An upper surface of the table body23has: a central portion23ahaving an approximately semicircular shape which is disposed approximately horizontally; and an inclined surface portion23bwhich expands radially outward in an oblique downward direction from the central portion23a. An outer peripheral portion of the inclined surface portion23bis formed into an arcuate shape in planar view, and is disposed at substantially the same height over the entire length. Although the central portion23aand the inclined surface portion23bare formed of a flat surface, for example, unevenness may be provided to the inclined surface portion23bwhen necessary. For example, a plurality of ribs extending in a radial direction may be formed on the inclined surface portion23b, and articles on the inclined surface portion23bmay be guided to the respective radial feeders4(seeFIG. 1andFIG. 2) by these ribs.

A bulkhead24is fixed to the table body23. The bulkhead24is disposed along a vertical direction. The bulkhead24is disposed so as to close both end portions of the table body23in the circumferential direction92.

The table base26is integrally formed with the table body23by way of the connecting units28. When vibrations are applied to the table base26, the table body23is integrally vibrated together with the table base26. Mounting units27a,27b,27care mounted on a plurality of places on an outer peripheral portion of the table base26in the circumferential direction92, and one end portions of first elastic units41(41a,41b,41c) described later are mounted on the mounting units27a,27b,27c. The plurality of these mounting units27a,27b,27care arranged such that distances from the central portion23ato the respective mounting units27a,27b,27care equal to each other and heights of the mounting units27a,27b,27care equal to each other.

The vibration mechanism30includes: a plurality of elastic unit groups40(40a,40b,40c) each having a first elastic unit41(41a,41b,41c) and a second elastic unit42(42a,42b,42c); a counterweight36connected to the dispersion table22by way of the elastic unit groups40(40a,40b,40c); and vibrating sources32,33which vibrate the dispersion table22by way of the elastic unit groups40(40a,40b,40c).

The counterweight36is disposed below the table base26of the dispersion table22. Mounting units38a,38b,38care mounted on a plurality of places on an outer peripheral portion of the counterweight36in the circumferential direction92. One end portions of the second elastic units42(42a,42b,42c) are mounted on the mounting units38a,38b,38c. A pair of through holes37a,37b(seeFIG. 5) which extends in a vertical direction is formed in the counterweight36.

The counterweight36is mounted on the frame16(seeFIG. 1) by way of a plurality of foot units39projecting downward from the counterweight36. The foot unit39includes a coil spring which is extendable and shrinkable in a vertical direction. Vibrations of the counterweight36are damped by the coil springs. With such a configuration, the transmission of vibrations to the frame16from the dispersing feed devices20a,20bis inhibited.

A connecting base49is disposed below the counterweight36. A plurality of connection members50a,50b,50care fixed to a plurality of places on an outer peripheral portion of the connecting base49in the circumferential direction92, and the plurality of connection members50a,50b,50care provided for the respective elastic unit groups40a,40b,40c. With such a configuration, the plurality of connection members50a,50b,50care integrally formed with each other by way of the common connecting base49.

Each connection member50(50a,50b,50c) includes: a horizontal portion51disposed approximately horizontally; and a rising portion52which is raised from the horizontal portion51. The horizontal portion51extends linearly along the circumferential direction92. The rising portion52extends upward from one end portion of the horizontal portion51.

In this embodiment, the vibrating sources are the first vibrating source32and the second vibrating source33. The first vibrating source32includes: a magnet coil32aand a stationary core32bmounted on the counterweight36; and a movable core32cmounted on the table base26of the dispersion table22. The second vibrating source33includes: a magnet coil33aand a stationary core33bmounted on the counterweight36; and a movable core33cmounted on the connecting base49. The magnet coil32aand the stationary core32bof the first vibrating source32are housed in one through hole37a(seeFIG. 5) formed in the counterweight36, and the magnet coil33aand the stationary core33bof the second vibrating source33are housed in the other through hole37b(seeFIG. 5) formed in the counterweight36.

A first current supply circuit71(seeFIG. 8) is electrically connected to the magnet coil32aof the first vibrating source32, and a second current supply circuit72(seeFIG. 8) is electrically connected to the magnet coil33aof the second vibrating source33. When an AC current flows into the magnet coils32a,33a, a vibration magnetic field is generated so that the movable cores32c,33cvibrate in a vertical direction.

The plurality of elastic unit groups40(40a,40b,40c) are arranged at different positions in the circumferential direction92(seeFIG. 7). In this embodiment, three elastic unit groups40a,40b,40care arranged at angular intervals of 60° in planar view. However, the number of elastic unit groups is not limited to such a number.

The plurality of elastic unit groups40a,40b,40care disposed parallel to each other between the dispersion table22and the counterweight36. In each elastic unit group40(40a,40b,40c), the first elastic unit41(41a,41b,41c) and the second elastic unit42(42a,42b,42c) are connected in series by way of the connection member50(50a,50b,50c).

Each of the first elastic unit41and the second elastic unit42is formed of an elongated member where the other end portion in a length direction is easily vibrated in a deflecting direction using one end portion in the length direction as a fulcrum. To be more specific, the first elastic unit41and the second elastic unit42are formed of a plurality of stacked leaf springs, for example. In this case, natural frequencies of the first elastic unit41and the second elastic unit42can be easily adjusted by changing the number of leaf springs. The first elastic unit41has first natural frequency f1, and the second elastic unit42has second natural frequency f2which differs from the first natural frequency f1.

The first elastic unit41is inclinedly disposed with respect to a vertical direction. The second elastic unit42is inclinedly disposed in a direction which differs from the inclination direction of the first elastic unit41with respect to the vertical direction. Although the inclination directions of the first elastic unit41and the second elastic unit42are not limited, for example, the first elastic unit41extends in a direction which is inclined downward toward one end in the circumferential direction92at an angle of 45°, and the second elastic unit42extends in a direction which is inclined downward toward the other end in the circumferential direction92at an angle of 45°. As viewed from the outside in the radial direction94(seeFIG. 7), the difference between the first elastic unit41and the second elastic unit42in terms of the inclination angle is set to 90°. Although the difference in inclination angle as viewed from the outside in the radial direction is not limited to such an angle, it is preferable that the difference in inclination angle be 60° or more.

An upper end portion of the first elastic unit41is fixed to the mounting unit27a,27b,27cof the dispersion table22. A lower end portion of the first elastic unit41extending in an oblique downward direction toward one end in the circumferential direction92from a connection with the dispersion table22is fixed to an upper end portion of the rising portion52of the connection member50. An upper end portion of the second elastic unit42is fixed to the mounting unit38a,38b,38cof the counterweight36. A lower end portion of the second elastic unit42extending in an oblique downward direction toward the other end in the circumferential direction92from a connection with the counterweight36is fixed to an end portion of the horizontal portion51of the connection member50on a side opposite to the rising portion52. With such a configuration, the lower end portion of the first elastic unit41and the lower end portion of the second elastic unit42are connected to each other in a compact manner in a vertical direction and in the circumferential direction92by the connection member50. The first elastic unit41and the second elastic unit42are arranged to overlap with each other in the vertical direction and in the circumferential direction92. With such a configuration, the first elastic unit41and the second elastic unit42are formed in a further compact manner in these directions.

The dispersing feed device of this embodiment is further described compared with a comparison example shown inFIG. 15. In the comparison example shown inFIG. 15, a first elastic unit241and a second elastic unit242are arranged at the same inclination angle in the same manner as this embodiment. Unlike the second elastic unit42of this embodiment where the upper end portion is connected to the counterweight36and the lower end portion is connected to the connection member50, the second elastic unit242of the comparison example is configured such that an upper end portion is connected to a connection member250and a lower end portion is connected to a counterweight236. That is, in the comparison example, a lower end portion of the first elastic unit241extending in an oblique downward direction from a dispersion table222and the upper end portion of the second elastic unit242extending in an oblique upward direction from the counterweight236are connected to each other by way of the connection member250. With such a connection structure, it is necessary to increase a distance in a vertical direction between the dispersion table222and the counterweight236and hence, the dispersing feed device becomes large-sized in the vertical direction as a whole. To the contrary, according to this embodiment, the lower end portion of the first elastic unit41and the lower end portion of the second elastic unit42are connected to each other and hence, it is possible to realize the compact arrangement in the vertical direction as a whole as described previously.

Operation of Dispersing Feed Device

The operation of the dispersing feed device20is described with reference toFIG. 7toFIG. 9.

FIG. 7is a plan view showing the arrangement of the dispersion table22, the plurality of elastic unit groups40a,40b,40cand the like of the dispersing feed device20. InFIG. 7, only the main members are illustrated, and the illustration of the other members is omitted.FIG. 8is a schematic side view for describing the vibration mechanism30. InFIG. 8, to facilitate the understanding of the configuration, only one elastic unit group40and one connection member50corresponding to the elastic unit group40are illustrated.FIG. 9is a graph showing one example of the relationship between frequency of vibrations generated by the vibrating sources32,33and amplitude of composite vibration transmitted to the dispersion table22.

All elastic unit groups40a,40b,40care also connected to the dispersion table22and the counterweight36using the same connection structures and hence, the mechanisms for transmitting vibrations of the first elastic unit41and/or the second elastic unit42to the dispersion table22are common among elastic unit groups40a,40b,40c.

The mechanism for transmitting vibrations of the first elastic unit41and/or the second elastic unit42to the dispersion table22is described with reference toFIG. 8by taking one elastic unit group40as an example.

The first elastic unit41and the second elastic unit42are connected to each other in series. Accordingly, vibrations can be applied to the dispersion table22in such a manner that only one of the first elastic unit41and the second elastic unit42is resonated and the resonated vibrations are applied to the dispersion table22, or both the first elastic unit41and the second elastic unit42are resonated, and the composite vibration consisting of the resonated vibrations are applied to the dispersion table22.

The first elastic unit41is inclinedly connected to the dispersion table22upward toward one end in the circumferential direction92. The second elastic unit42is inclinedly connected to the dispersion table22downward toward the same direction in the circumferential direction92by way of the connection member50and the first elastic unit41.

When an AC current is supplied to the first vibrating source32from the first current supply circuit71, vibrations in a vertical direction of the movable core32cof the first vibrating source32are transmitted to the upper end portion of the first elastic unit41by way of the table base26of the dispersion table22. When frequency of the vibrations is first natural frequency f1or frequency near the first natural frequency f1, the first elastic unit41resonates. Accordingly, the upper end portion of the first elastic unit41swings in an inclination direction81perpendicular to a length direction of the first elastic unit41around the lower end portion of the first elastic unit41as a fulcrum, and the vibrations in the inclination direction81are transmitted to the dispersion table22.

When an AC current is supplied to the second vibrating source33from the second current supply circuit72, vibrations in a vertical direction of the movable core33cof the second vibrating source33are transmitted to the lower end portion of the second elastic unit42by way of the connecting base49and the connection member50. When frequency of the vibrations is second natural frequency f2or frequency near the second natural frequency f2, the second elastic unit42resonates. Accordingly, the lower end portion of the second elastic unit42swings in an inclination direction82perpendicular to a length direction of the second elastic unit42around the upper end portion of the second elastic unit42as a fulcrum, and the vibrations in the inclination direction82are transmitted to the dispersion table22by way of the connection member50and the first elastic unit41.

The second elastic unit42can resonate in the same manner as described above also due to vibrations of the first vibrating source32. That is, when vibrations having second natural frequency f2or frequency near the second natural frequency f2are generated by the first vibrating source32, the vibrations are transmitted to the lower end portion of the second elastic unit42from the movable core32cby way of the table base26, the first elastic unit41and the connection member50, and the second elastic unit42resonates in the same manner as described above.

When only the first elastic unit41resonates, vibrations in a direction inclined toward the circumferential direction92with respect to the vertical direction are applied to the dispersion table22at the position in the circumferential direction where the dispersion table22is connected to the elastic unit group40and hence, articles on the dispersion table22bounces obliquely upward. Accordingly, the articles on the dispersion table22are fed in a first direction D1in the circumferential direction92. On the other hand, when only the second elastic unit42resonates, vibrations in a direction inclined toward a side opposite to the circumferential direction92with respect to the vertical direction are applied to the dispersion table22at the position in the circumferential direction where the dispersion table22is connected to the elastic unit group40and hence, articles on the dispersion table22bounces obliquely upward on a side opposite to the case where only the first elastic unit41resonates. Accordingly, the articles on the dispersion table22are fed in a second direction D2opposite to the first direction D1in the circumferential direction92.

When both the first elastic unit41and the second elastic unit42resonate, composite vibration transmitted to the dispersion table22can be controlled in various modes by controlling frequency and a phase of vibrations generated by the vibrating sources32,33. Accordingly, for example, it is possible to make article on the dispersion table22bounce upward, move along a trajectory which draws an ellipse or move back and forth in the circumferential direction92without causing the displacement of the articles in the circumferential direction92.

With reference toFIG. 9, one example of preferred frequency of vibrations generated by the vibrating sources32,33is described. In this case, the first natural frequency f1and the second natural frequency f2are set sufficiently larger than the natural frequency f0of the coil spring of the foot unit39and the first natural frequency f1is larger than the second natural frequency f2.

As shown inFIG. 9, when vibrations having frequency which is equal to either one of the first natural frequency f1and the second natural frequency f2are generated, the first elastic unit41or the second elastic unit42resonates and hence, amplitude of vibrations transmitted to the dispersion table22reaches peaks. In a frequency region near these peaks, amplitude of vibrations transmitted to the dispersion table22sharply decreases, and there is a tendency that a gradient which indicates the decrease of the amplitude becomes gentle on a high frequency side of the peak compared to a low frequency side of the peak. Therefore, composite vibration of large amplitude can be acquired in the case where frequencies of vibrations generated by the vibrating sources32,33are deviated to a high frequency side of the peak compared to the case where frequency of the vibrations generated by the vibrating sources32,33is deviated to a low vibration side of the peak. Accordingly, when the first elastic unit41is resonated singly, to take an error in frequency into consideration, as indicated by reference number G1inFIG. 9, it is preferable to generate vibrations having frequency slightly larger than the first natural frequency f1by the first vibrating source32. In the same manner, when the second elastic unit42is resonated singly, as indicated by reference number G2inFIG. 9, it is preferable to generate vibrations having frequency slightly larger than the second natural frequency f2by the second vibrating source33or the first vibrating source32.

When both the first elastic unit41and the second elastic unit42are resonated at common frequency, as indicated by reference number G3inFIG. 9, vibrations may be generated at frequency between the first natural frequency f1and the second natural frequency f2. In this case, only the first vibrating source32may be driven or both the first vibrating source32and the second vibrating source33may be driven at the same frequency. In this case, by adjusting frequency of the vibrating source to approach the first natural frequency f1, amplitude of vibrations of the first elastic unit41is increased so that it is possible to increase a feed rate of articles toward the first direction D1(seeFIG. 8) in the circumferential direction92. On the other hand, by adjusting frequency of the vibrating source to approach the second natural frequency f2, amplitude of vibrations of the second elastic unit42is increased so that it is possible to increase a feed rate of articles toward the second direction D2(seeFIG. 8) in the circumferential direction92. To allow both the first elastic unit41and the second elastic unit42to resonate at the same frequency, the first natural frequency f1and the second natural frequency f2may be preliminarily set to values close to each other. On the other hand, to make either one of the first elastic unit41and the second elastic unit42always resonate singly, the first natural frequency f1and the second natural frequency f2may be preliminarily set such that the difference between both frequencies to have a sufficient value (for example, 10 Hz or more).

The first vibrating source32and the second vibrating source33may be driven at different frequencies. In this case, amplitude of vibrations of the first elastic unit41and amplitude of vibrations of the second elastic unit42can be individually adjusted. Due to such adjustment, the direction and amplitude of composite vibration transmitted to the dispersion table22can be more finely adjusted and hence, articles on the dispersion table22can be moved in the various modes described above.

As shown inFIG. 7, the plurality of elastic unit groups40a,40b,40care arranged at intervals in the circumferential direction92, and the elastic unit groups40a,40b,40care connected to the dispersion table22at positions different from each other in the circumferential direction92. By providing the plurality of elastic unit groups40a,40b,40cin a distributed manner in the circumferential direction92, a load applied to the respective elastic unit groups40a,40b,40cfrom the dispersion table22can be distributed. Accordingly, durability of the respective first elastic units41a,41b,41cand the respective second elastic units42a,42b,42ccan be enhanced.

In the respective elastic unit groups40a,40b,40c, the first elastic unit41a,41b,41cand the second elastic unit42a,42b,42care arranged on a straight line in planar view. InFIG. 7, to facilitate the understanding of the configuration, the entire structure of the second elastic units42a,42b,42cis shown. However, to describe the configuration in a strict manner, one end portions of the second elastic units42a,42b,42care arranged so as to be hidden below the first elastic units41(seeFIG. 3andFIG. 4).

The plurality of elastic unit groups40a,40b,40care arranged at positions different from each other in planar view and at respective angles different from the radial direction94. With such a configuration, it is possible to apply vibrations in different directions to the dispersion table22at a plurality of places in the circumferential direction92. Accordingly, it is possible to feed articles on the dispersion table22in a twisting direction about the central portion23ain planar view.

At a predetermined position on the dispersion table22, the direction of feeding articles due to vibrations applied from the elastic unit group40a,40b,40ccorresponding to this position is the first direction D1or the second direction D2in the circumferential direction92as described above. Further, to the articles on the dispersion table22, a force which feeds the articles in the direction D3inclined downwardly toward the outside in the radial direction94is applied due to inclination of the inclined surface portion23bof the table body23and gravity. Accordingly, in an actual operation, the articles on the dispersion table22are fed to either one of two directions D4, D5inclined downwardly toward the outside in the radial direction94as well as in the circumferential direction92.

By driving the vibrating sources32,33such that these feeding directions D4, D5and a feeding amount of the articles can be suitably switched, articles at a predetermined position on the dispersion table22can be fed to a desired position on the outer peripheral portion. Accordingly, articles which are dropped and supplied to the central portion23aand the peripheral portion of the dispersion table22from above can be properly supplied to the plurality of sections on the outer peripheral portion of the dispersion table22while inhibiting unevenness of dispersion of the articles on the dispersion table22.

Control System

The control system of the weighing device1is described with reference toFIG. 10.

Various operations of the weighing device1are controlled by the controller100. The controller100includes: a control unit102which controls respective operations of conveying units6of the plurality of radial feeders4, gating units62of the plurality of weighing hoppers10, and a first current supply circuit71and a second current supply circuit72of the dispersing feed devices20a,20b; a calculation unit104which performs various calculations necessary for a control executed by the control unit102; and a storage unit106which stores various information necessary for the control executed by the control unit102.

Respective signals transmitted from the dispersion unevenness detecting unit64which detects unevenness of dispersion of articles on the dispersion table22and the weight measuring sensors12which measure weights of the articles held by the weighing hoppers10are inputted to the controller100. The dispersion unevenness detecting unit64may be, for example, a multi-point cell type weight measuring sensor equipped with a plurality of load cells mounted on a lower surface of the dispersion table22or an image sensor which images articles on the dispersion table22from above. Further, the unevenness of dispersion of articles on the dispersion table22may be estimated based on measured weight values of the weight measuring sensors12of the plurality of weighing hoppers10.

The control unit102outputs control signals to the conveying unit6, the gating unit62, the first current supply circuit71and the second current supply circuit72based on information calculated by the calculation unit104, information stored in the storage unit106and/or various input signals.

To acquire a combined measured weight value as close as possible to a set weight, it is preferable that articles of a weight which falls within a predetermined range be held in the weighing hopper10. To allow all weighing hoppers10to hold articles of a weight which falls within the predetermined range, the control unit102controls a feed amount of articles to the respective weighing hoppers10by controlling operations of the first current supply circuit71and the second current supply circuit72of the dispersing feed devices20a,20b, and operations of the conveying units6of the radial feeders4. With such a control, a feed amount of articles from the dispersing feed devices20a,20bto the respective radial feeders4can be adjusted, and a conveyance amount of articles by the respective radial feeders4is adjusted and hence, proper amounts of articles are supplied to the respective weighing hoppers10. To perform such a control, the calculation unit104calculates target values of feed amounts of articles to the weighing hoppers10based on weights measured by the weight measuring sensors12for the respective weighing hopper10.

The control of the dispersing feed devices20a,20bby the control unit102is performed based on target values calculated by the calculation unit104, and the unevenness of dispersion of articles detected by dispersion unevenness detecting unit64. In this control, driving of the first vibrating source32and/or the second vibrating source33is controlled by controlling the first current supply circuit71and the second current supply circuit72and hence, a mode of vibrations applied to the dispersion table22can be controlled.

For example, when excessive amount of articles are present on one end in the circumferential direction92on the dispersion table22, to increase a feeding amount of the articles toward the other end in the circumferential direction92, amplitude and a phase of vibrations of the first elastic unit41or the second elastic unit42are adjusted by controlling frequency and/or a phase of the vibrating sources32,33. With such a control, it is possible to feed the articles toward the outer peripheral portion of the dispersion table22while distributing the articles from one end side to the other end side in the circumferential direction92on the dispersion table22. With such an operation, feed amounts of the articles from the dispersion table22to the plurality of radial feeders4can be made uniform.

Further, for example, in the case of increasing a feed amount of the articles to the weighing hopper10of which articles holding amount is smaller than a predetermined range, frequencies and/or phases of the vibrating sources32,33are controlled so that amplitude and a phase of the vibrations of the first elastic unit41or the second elastic unit42are adjusted whereby the articles are moved toward a discharge portion to the radial feeder4corresponding to the weighing hopper10described above from a portion on the dispersion table22where the articles are present in a relatively dense manner. On the other hand, in the case of inhibiting the supply of articles to the weighing hopper10where an article holding amount is larger than a predetermined range, amplitude and a phase of vibrations of the first elastic unit41or the second elastic unit42is adjusted such that the articles in the portion where the articles are relatively densely present on the dispersion table22reach the outer peripheral portion of the dispersion table22at a position displaced from the discharge portion to the radial feeder4corresponding to the above-mentioned weighing hopper10in the circumferential direction92. With such an operation, a feed amount of articles from the dispersion table22to the radial feeder4can be adjusted for every radial feeder4. By combining a control of conveyance by the radial feeders4to a control of feed amounts to the radial feeders4, the articles holding amount of the individual weighing hoppers10can be adjusted. Accordingly, it is possible to perform combination weighing with high accuracy.

Second Embodiment

The second embodiment is described with reference toFIG. 11toFIG. 14. In the second embodiment, the overall configuration of a weigh measuring device1and the configuration of a control system for the weighing device1are similar to them of the first embodiment.

In the second embodiment, one dispersing feed device120equipped with a dispersion table122having a circular shape in planar view is mounted on the weighing device1(seeFIG. 1andFIG. 2). The dispersing feed device120includes a single dispersion table122. The dispersion table122includes: a table body123having an approximately conical upper surface; and a table base126which supports the table body123by way of connecting units128.

An upper surface of the table body123has: a central portion123ahaving an approximately circular shape which is disposed approximately horizontally; and an inclined surface portion123bwhich expands obliquely downward toward the outside in a radial direction from the central portion123a. An outer peripheral portion of the inclined surface portion123bis formed into a circular shape in planar view, and is disposed at substantially the same height over the entire length. Although the central portion123aand the inclined surface portion123bare formed of a flat surface, for example, unevenness may be provided to the inclined surface portion123bwhen necessary. For example, a plurality of ribs extending in a radial direction may be formed on the inclined surface portion123b, and articles on the inclined surface portion123bmay be guided to respective radial feeders4(seeFIG. 1andFIG. 2) by these ribs.

The table base126is integrally formed with the table body123by way of the connecting units128. When vibrations are applied to the table base126, the table body123is integrally vibrated together with the table base126. Mounting units127a,127b,127care mounted on a plurality of places on an outer peripheral portion of the table base126in the circumferential direction192, and one end portions of first elastic units141(141a,141b,141c) described later are mounted on the mounting units127a,127b,127c. The plurality of these mounting units127a,127b,127care arranged such that distances from the central portion123ato the respective mounting units127a,127b,127care equal to each other and heights of the mounting units127a,127b,127care equal to each other.

The dispersing feed element120includes a vibration mechanism130which applies vibrations to the dispersion table122. The vibration mechanism130includes: a plurality of elastic unit groups140(140a,140b,140c) each having a first elastic unit141(141a,141b,141c) and a second elastic unit142(142a,142b,142c); a counterweight136connected to the dispersion table122by way of the elastic unit groups140(140a,140b,140c); and vibrating source132which vibrates the dispersion table122by way of the elastic unit groups140(140a,140b,140c).

The counterweight136is disposed below the table base126of the dispersion table122. Mounting units138a,138b,138care mounted on a plurality of places on an outer peripheral portion of the counterweight136in the circumferential direction192. One end portions of the second elastic units142(142a,142b,142c) are mounted on the mounting units138a,138b,138c. The mounting units138a,138b,138cproject upward from the counterweight136. Upper ends of these mounting units138a,138b,138care disposed at substantially the same height as upper ends of the mounting units127a,127b,127cof the dispersion table122. Through hole137(seeFIG. 13) which extends in a vertical direction is formed in the counterweight136.

The counterweight136is mounted on the frame16(seeFIG. 1) by way of a plurality of foot units139projecting downward from the counterweight136. The foot unit139includes a coil spring which is extendable and shrinkable in a vertical direction. Vibrations of the counterweight136are damped by the coil springs. With such a configuration, the transmission of vibrations to the frame16from the dispersing feed device120is inhibited.

The dispersing feed device120includes a connection frame149which is arranged so as to surround the counterweight136from the outside in a radial direction194(seeFIG. 14). The connecting frame149has an approximately triangular planar shape. A first connecting unit151and a second connecting unit152are mounted on each vertex portion of the connecting frame149in a state where the first connecting unit151and the second connecting unit152are arranged in a spaced apart manner in a circumferential direction192. The first connecting unit151and the second connecting unit152are provided for every elastic unit group140a,140b,140c. The plurality of first connecting units151and the plurality of second connecting units152are integrally formed with each other by way of the common connecting frame149.

In the second embodiment, only one vibrating source132is provided. However, in the same manner as the first embodiment, a plurality of vibrating sources may be mounted on the dispersing feed device120. The vibrating source132includes: a magnet coil132aand a stationary core132bmounted on the counterweight136; and a movable core132cmounted on the table base126of the dispersion table122. The magnet coil132aand the stationary core132bare housed in the through hole137(seeFIG. 13) formed in the counterweight136.

When an AC current is supplied from the current supply circuit (not shown in the drawing) to the magnet coil132aof the vibrating source132, a vibration magnetic field is generated so that the movable core132cvibrates in a vertical direction.

The plurality of elastic unit groups140(140a,140b,140c) are arranged at different positions in the circumferential direction192(seeFIG. 14). In the second embodiment, three elastic unit groups140a,140b,140care arranged at angular intervals of 120° in planar view. However, the number of elastic unit groups is not limited to such a number.

The plurality of elastic unit groups140a,140b,140care disposed parallel to each other between the dispersion table122and the counterweight136. In each elastic unit group140(140a,140b,140c), the first elastic unit141(141a,141b,141c) and the second elastic unit142(142a,142b,142c) are connected in series by way of the first connecting unit151and the second connecting unit152.

The first elastic unit141is a member which is similar to the first elastic unit41in the first embodiment, and the first elastic unit141has first natural frequency f1. The second elastic unit142is a member which is similar to the second elastic unit42in the first embodiment, and the second elastic unit142has second natural frequency f2.

The inclination direction of the first elastic unit141with respect to the vertical direction is similar to the inclination direction of the first elastic unit41in the first embodiment, and the inclination direction of the second elastic unit142with respect to the vertical direction is similar to the inclination direction of the second elastic unit42in the first embodiment. That is, also in the second embodiment, the first elastic unit141and the second elastic unit142are inclinedly arranged in different directions.

An upper end portion of the first elastic unit141is fixed to the mounting unit127a,127b,127cof the dispersion table122. An upper end portion of the second elastic unit142is fixed to the mounting unit138a,138b,138cof the counterweight136. An upper end portion of the first elastic unit141and an upper end portion of the second elastic unit142are disposed at substantially the same height.

A lower end portion of the first elastic unit141extending obliquely downward toward one end in the circumferential direction192from a connection with the dispersion table122is fixed to the first connecting unit151. A lower end of the second elastic unit142extending obliquely downward toward the other end in the circumferential direction192from a connection with the counterweight136is fixed to the second connecting unit152. The lower end portion of the first elastic unit141and the lower end portion of the second elastic unit142are disposed at substantially the same height.

In this manner, the almost entirety of the first elastic unit141and the almost entirety of the second elastic unit142are disposed in an overlapping manner in the vertical direction. Accordingly, it is possible to connect the first elastic unit141and the second elastic unit142having different inclination directions in a compact manner in the vertical direction.

All elastic unit groups140a,140b,140care connected to the dispersion table122and the counterweight136using the same connection structures and hence, the mechanisms for transmitting vibrations of the first elastic unit141and/or the second elastic unit142are common among the elastic unit groups140a,140b,140c.

The first elastic unit141and the second elastic unit142are connected to each other in series as described above. Accordingly, vibrations can be applied to the dispersion table122in such a manner that only one of the first elastic unit141and the second elastic unit142is resonated and the resonated vibrations are applied to the dispersion table122, or both the first elastic unit141and the second elastic unit142are resonated, and combined resonated vibrations are applied to the dispersion table122.

The first elastic unit141is inclinedly connected to the dispersion table122upward toward one end in the circumferential direction192. The second elastic unit142is inclinedly connected to the dispersion table122downward toward the same direction in the circumferential direction192by way of the second connecting unit152, the first connecting unit151and the first elastic unit141.

When an AC current is supplied to the vibrating source132, vibrations in a vertical direction of the movable core132cof the vibrating source132are transmitted to the upper end portion of the first elastic unit141by way of the table base126of the dispersion table122. The vibrations are also transmitted to a lower end portion of the second elastic unit142by way of the first elastic unit141, the first connecting unit151and the second connecting unit152.

When frequency of the vibrations is first natural frequency f1or frequency near the first natural frequency f1, the first elastic unit141resonates. Accordingly, the upper end portion of the first elastic unit141swings in an inclination direction181perpendicular to a length direction of the first elastic unit141around the lower end portion of the first elastic unit141as a fulcrum (seeFIG. 11), and the vibrations in the inclination direction181are transmitted to the dispersion table122.

On the other hand, when frequency of the vibrations is second natural frequency f2or frequency near the second natural frequency f2, the second elastic unit142resonates. Accordingly, the lower end portion of the second elastic unit142swings in an inclination direction182perpendicular to a length direction of the second elastic unit142around the upper end portion of the second elastic unit142as a fulcrum (seeFIG. 11), and the vibrations in the inclination direction182are transmitted to the dispersion table122by way of the first connecting unit151, the second connecting unit152and the first elastic unit141.

When only the first elastic unit141resonates, vibrations in a direction181inclined in the circumferential direction192with respect to the vertical direction (seeFIG. 11) are applied to the dispersion table122at the position in the circumferential direction where the dispersion table122is connected to the elastic unit group140and hence, articles on the dispersion table122are fed in a first direction E1in the circumferential direction192. On the other hand, when only the second elastic unit142resonates, vibrations in a direction182inclined toward a side opposite to the circumferential direction192with respect to the vertical direction (seeFIG. 11) are applied to the dispersion table122at the position in the circumferential direction where the dispersion table122is connected to the elastic unit group140and hence, articles on the dispersion table122are fed in a second direction E2opposite to the first direction E1in the circumferential direction192.

When both the first elastic unit141and the second elastic unit142resonate, composite vibration transmitted to the dispersion table122can be controlled in various modes by controlling frequency and a phase of vibrations generated by the vibrating source132in the same manner as the first embodiment.

FIG. 14is a plan view showing the arrangement of the dispersion table122, the plurality of elastic unit groups140a,140b,140cand the like of the dispersing feed device120. InFIG. 14, only the main members are illustrated, and the illustration of the other members is omitted.

As shown inFIG. 14, the plurality of elastic unit groups140a,140b,140care arranged at intervals in the circumferential direction192, and the elastic unit groups140a,140b,140care connected to the dispersion table122at positions different from each other in the circumferential direction192. By providing the plurality of elastic unit groups140a,140b,140cin a distributed manner in the circumferential direction192, a load applied to the respective elastic unit groups140a,140b,140cfrom the dispersion table122can be distributed. Accordingly, durability of the respective first elastic units141a,141b,141cand the respective second elastic units142a,142b,142ccan be enhanced.

The plurality of elastic unit groups140a,140b,140care arranged at positions different from each other in planar view and at respective angles different from the radial direction194. With such a configuration, it is possible to apply vibrations in different directions to the dispersion table122at a plurality of places in the circumferential direction192. Accordingly, it is possible to feed articles on the dispersion table122in a twisting direction about the central portion123ain planar view.

At a predetermined position on the dispersion table122, the direction of feeding articles due to vibrations applied from the elastic unit group140a,140b,140ccorresponding to this position is the first direction E1or the second direction E2in the circumferential direction192as described above. Further, to the articles on the dispersion table122, a force which feeds the articles in the direction E3inclined downward toward the outside in the radial direction194is applied due to inclination of the inclined surface portion123bof the table body123and gravity. Accordingly, in an actual operation, the articles on the dispersion table122are fed to either one of two directions E4, E5inclined downward toward the outside in the radial direction194as well as in the circumferential direction192.

By driving the vibrating source132such that these feeding directions E4, E5and a feeding amount of the articles can be suitably switched, articles at a predetermined position on the dispersion table122can be fed to a desired position on the outer peripheral portion. Accordingly, articles which are dropped and supplied to the central portion123aand the peripheral portion of the dispersion table122from above can be properly supplied to the plurality of sections on the outer peripheral portion of the dispersion table122while inhibiting unevenness of dispersion of the articles on the dispersion table122.

The dispersing feed device120according to the second embodiment having the above-mentioned configuration is controlled by the control system described in conjunction with the first embodiment. Accordingly, by controlling driving of the vibrating source132in the same manner as the first embodiment, a mode of vibrations applied to the dispersion table122can be controlled. Accordingly, the unevenness of dispersion of the articles on the dispersion table122can be inhibited and, at the same time, proper amounts of articles can be supplied to the respective weighing hoppers10and hence, accuracy of combination weighing can be increased.

Although the present invention has been described by exemplifying the above-mentioned embodiments heretofore, the present invention is not limited to the above-mentioned embodiments.

For example, in the above-mentioned embodiments, the description has been made with respect to the cases where a dispersion table having a circular shape in a plan view and the dispersion table having a semicircular shape in a plan view are used. In the present invention, however, a planar shape of the dispersion table is not particularly limited as long as the planar shape continues in a circumferential direction about a vertical direction. For example, the dispersion table may have a shape formed by dividing a circle in three or more in a circumferential direction or a polygonal shape.

In the above-mentioned embodiments, the description has been made with respect to the example where each elastic unit group is formed of two elastic units. However, an elastic unit group may be formed of three or more elastic units which differ from each other in an inclination direction with respect to a vertical direction and natural frequency.

In the above-mentioned embodiments, the description has been made with respect to the dispersing feed device equipped with one or two vibrating sources. However, the dispersing feed device may have three or more vibrating sources. Further, the vibrating source is not limited to a vibrating source which includes a magnet coil and a movable core and, for example, a vibrating source formed of a piezoelectric element may be used.

PARTS LIST