Method for providing a predetermined number of contiguous stored elements forming a line, device for carrying out said method, and a combination weighing machine comprising said device

Abstract

A method for providing a predetermined number of contiguous stored elements (A,B,C,D,E,F,G), that is which are touching each other, and in a line (2) in a supply chute (3) along which the line (2) may advance, these elements being essentially spheroidal, such as fruit, wherein initially the first element (A) in the line (2) is retained by retention means (4), comprising the operation of counting, by means of the emission and detection of a steady beam (6) of light, the signal variations produced in said detection by the line (2) advancing, specifically by the passage of the spaces between two consecutive elements in the line (2) through the detection beam (6), aiming the beam (6) at the gaps (7) that necessarily will be formed in the line (2) between two consecutive elements even if they are contiguous, due to the effect of said elements (A,B,C,D,E,F,G) being spheroidal.

Claims

1. A device capable of providing a predetermined number of stored elements forming a line and touching each other, comprising: a supply chute along which the line may advance, said elements being essentially spheroidal; retention means, capable to be actuated by a motor, adapted to retaining a first element in the line and preventing the line from sliding and advancing, and to stop retaining the first element in the line, allowing the line to advance along the chute; and a light emitter and detector that emits a steady beam of light aimed at the chute, adapted to count signal variations produced in said beam by the advance of the line, specifically by the passage of the spaces between two consecutive elements in the line through the detection beam, the beam being aimed at the gaps that necessarily will be formed in the line between two consecutive elements even if they are in contact with each other, due to the effect of said elements being spheroidal, and adapted to actuating the retention means to stop retaining the first element in the line, and actuating again the retention means to retain a next element in the line when the signal variations reach a number equal to the predetermined number of elements; and wherein the retention means comprises a flexible gripper configured to adapt to a contour of the first element in the line, wherein the gripper is mounted on an end of a pivoting support that is actuated by a connecting rod and crank mechanism, the crank being articulated at one end to the pivoting support at a point near to the gripper and at the other end to the connecting rod, and said connecting rod being actuated by the motor, such that rotations of the motor in one direction raises the gripper, allowing the line of elements to advance along the chute, and rotation of the motor in the opposite direction descends the gripper until contacting the first element in the line to retain the first element in the line in the chute.

2. The device according to claim 1, wherein the light emitter and detector are configured to count the variations in an intensity of the detection beam, so that during the step of detecting the beam, each time a reduction in the intensity of the reflected beam is detected, below a predetermined threshold, and immediately thereafter an increase in the intensity of the reflected beam, above a predetermined threshold, a space is counted.

3. The device according to claim 1, wherein the supply chute has a V-shaped transverse cross section determining two walls joined by a bottom vertex, the detection beam being aimed adjacent to one of the walls to strike the other wall at a point that is located away from the bottom vertex.

4. The device according to claim 3, wherein said distance between the striking point of the detection beam and the bottom vertex of the chute is between 0.1 and 30 millimeters.

5. The device according to claim 4, wherein the detection beam is parallel to said first wall of the chute, and the distance separating the beam from said first side wall of the chute is 3 to 5 mm.

6. The device according to claim 1, wherein the striking point of the detection beam is arranged upstream from the retention means.

7. The device according to claim 1, wherein the motor is a motor with torque control, whose torque calibration depends on a size of the elements supplied in the chute, and allows the motor to be stopped during a retention maneuver when the resistive torque surpasses a previously calibrated value.

8. The device according to claim 1, wherein a tilt of the chute is greater than 4.

9. The device according to claim 8, wherein the tilt of the chute is 8.

10. The device according to claim 1, wherein the chute is provided with a vibrator that delivers a vibration of at least 5 millimeters of amplitude with a frequency of more than 40 Hz.

11. A machine comprising: a plurality of devices according to claim 1; and control means adapted to indicate, to each device, the number of elements each device should provide to a bucket that the respective chute opens into.

12. The machine according to claim 11, wherein every two devices provide elements to the same bucket.

13. A method for dispensing a predetermined number of elements from a chute, each element having a spheroidal shape, comprising: aligning elements in a single file with the chute so that the elements are in the single file abutting one another at abutments points; controlling advancement of the single file of elements down the chute by selectively blocking a leading element in the single file; emitting a beam of light across the chute at a location that is below the abutment points; counting each element that crosses the beam of light by detecting signal variations produced in the beam of light, the signal variations corresponding to gaps between two consecutive abutting elements at a location where the two elements do not abut each other due to the spheroidal shape of the elements; stopping the advancement of the single file of elements down the chute after the signal variations reach a predetermined number.

14. The method according to claim 13, wherein the signal variations are variations in an intensity of the beam of light.

15. The method according to claim 14, wherein during the step of detecting signal variations, each time a reduction in the intensity of the beam of light is detected, below a predetermined threshold, and immediately thereafter an increase in the intensity of the beam of light, above a predetermined threshold, a space is counted.

16. The device according to claim 1, wherein the elements are fruit.

17. The method according to claim 13, wherein the elements are fruit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The attached drawings illustrate, by way of a non-limiting example, a preferred embodiment of the device that is able to provide a predetermined number of contiguously stored pieces of fruit, in this example oranges, forming a line, and of a combination weighing machine comprising said devices. In said drawings:

(2) FIG. 1 is a perspective view of the device for providing a predetermined number of contiguously stored oranges forming a line;

(3) FIG. 2a is a schematic view in transverse cross section of the supply chute, showing the detection beam striking the wall of the chute after passing through the gap between two contiguous oranges;

(4) FIG. 2b is a schematic view in transverse cross section of the supply chute, showing the detection beam directly striking an orange;

(5) FIG. 2c is a schematic view of the effect achieved by aiming the beam of light at the optimal area, regardless of the size of the oranges;

(6) FIGS. 3a to 3g, respectively, show the sequence of counting the oranges provided by the device object of the invention as the line of contiguous oranges advances along the chute, indicating the striking point of the detection beam of light, and further showing a graph of the variations in intensity detected by the beam of light;

(7) FIG. 4 is a perspective view of the retention means showing the transmission mechanism of the gripper;

(8) FIG. 5 is a perspective view of a combination weighing machine comprising a plurality of said devices object of the invention; and

(9) FIG. 6 is a perspective view of an embodiment with two devices object of the invention that provide elements to the same bucket.

DETAILED DESCRIPTION OF THE DRAWINGS

(10) FIG. 1 shows a device 1 for providing a predetermined number of contiguous stored elements A,B,C,D,E,F,G in a line 2, that is which are touching each other, comprising a supply chute 3 along which the line 2 may advance through gravity, these elements A,B,C,D,E,F,G being essentially spheroidal, in this example oranges; retention means 4 adapted to retain the first element A in the line 2 and to prevent the line 2 from sliding and advancing, and to stop retaining the first element A in the line 2, allowing the line 2 to advance along the chute 3; and emission and detection means 5 of a steady beam 6 of light aimed at the chute 3 and adapted to count the variations in the intensity (I) signal of the detection beam 6, as will be explained further on.

(11) The method carried out by the device 1 to provide a predetermined number of oranges A,B,C,D,E,F,G comprises the operations of: a) actuating the retention means 4 to stop retaining the first orange A in the line 2, allowing the line 2 to advance along the chute 3, b) counting, by means of the emission and detection of a steady beam 6 of light, the signal variations produced in said detection by the advance of the line 2, specifically by the passage of the spaces between two consecutive oranges in the line 2 through the detection beam 6, aiming the beam 6 at the gaps 7 that necessarily will be formed in the line 2 between two consecutive oranges even if they are contiguous, due to the effect of said oranges A,B,C,D,E,F,G being spheroidal, and c) when the signal variations reach a number equal to the predetermined number of oranges that is wished to provide, for example three oranges A,B,C, actuating again the retention means 4 to retain the new first orange D in the line 2.

(12) In FIGS. 2a and 2b it can be seen how the supply chute 3 has a V-shaped transverse cross section determining two walls 3a,3b joined by a bottom vertex 3c, the detection beam 6 being aimed adjacent to one of the walls 3a to strike the other wall 3b at a point that is a predetermined distance z away from the bottom vertex 3c. In the illustrated embodiment it can be seen how the detection beam 6 is parallel to said first wall 3a of the chute 3. Moreover, in this example, the distance z between the striking point of the detection beam 6 and the bottom vertex 3c is 4 millimeters, and the angle formed between walls 3a and 3b is 90 degrees.

(13) In this way, regardless of the size of the oranges, the detection beam 6 will be able to detect the gap 7 between every two contiguous oranges, as a result of the striking point of the detection beam 6 being focused on an area at the bottom of the chute 3, as illustrated schematically in FIG. 2c, wherein two superimposed lines of differently sized oranges have been illustrated. In this example, it can be seen how the detection beam 6 makes it possible to detect the gap 7 that necessarily will be formed between two contiguous oranges, both in the line of larger oranges A, B and in the line of smaller oranges a, b, c.

(14) Each time a reduction in the intensity (I) of the reflected beam 6 is detected, below a predetermined threshold (Ith), and immediately thereafter an increase in the intensity (I) of the reflected beam, above a predetermined threshold (Ith), a space is counted. In other words, the reduction in the intensity (I) of the reflected beam 6 is brought about when the beam 6 travels a greater length, in this case when it passes through a gap 7 between two contiguous oranges A,B, hitting a wall 3b of the chute 3 (see FIG. 2a), while the increase in intensity (I) is brought about when the beam 3 of light hits the surface of one of the oranges B (see FIG. 2b).

(15) In one form of embodiment, the detection beam 6 is a laser beam. Specifically, a laser photocell with a built-in amplifier is arranged. In one example, the diameter of the point of light is 0.5 mm. The implementation of the invention was favourable using, for example, a model E3Z laser photocell with built-in amplifier commercialized by Omron.

(16) FIGS. 3a to 3g, respectively, show a sequence of counting the oranges A,B,C,D,E,F,G provided by the device 1 as the line 2 of contiguous oranges advances along the chute 3, indicating the striking point of the beam 6 of light, and further showing a graph of the variations in intensity (I) detected by the beam 6 of light.

(17) In the example shown, the predetermined number of oranges that is wished to provide is three oranges A, B, C.

(18) FIG. 3a shows the initial moment when, while the first orange A in the line 2 is retained by the retention means 4, the detection beam 6 strikes said first orange A. The graph shows that an intensity (I) value has been detected that is higher than the predetermined threshold (Ith) value.

(19) FIG. 3b shows the moment at which said first orange A is released by the retention means 4, and begins to advance over the chute 3 such that the beam 6 of light detects the gap 7 between this first orange A and the second continuous orange B in the line 2. The graph shows how the intensity (I) value detected is, at this moment, lower than the predetermined threshold (Ith) value.

(20) FIG. 3c shows the moment at which the line 2 continues to advance such that the beam 6 of light detects the second orange B in the line 2. At this instant, the graph again shows an intensity (I) value that is higher than the predetermined threshold (Ith) value.

(21) As a result, the detection means 5 count a first space since, as has already been mentioned, each time a reduction in the intensity (I) of the reflected beam 6 is detected, below a predetermined threshold (Ith), and immediately thereafter an increase in the intensity (I) of the reflected beam, above a predetermined threshold (Ith), a space is counted. Therefore, this first counted space indicates that the device has provided a first orange A.

(22) FIG. 3d shows the moment at which the line 2 continues to advance such that the beam 6 of light detects the gap 7 between the second orange B and the third contiguous orange C in the line 2. The graph shows how the intensity (I) value detected is again lower than the predetermined threshold (Ith) value.

(23) FIG. 3e shows the moment at which the line 2 continues to advance such that the beam 6 of light detects the third orange C in the line 2. At this instant, the graph again shows an intensity (I) value that is higher than the predetermined threshold (Ith) value. As a result, the detection means 5 count a second space, which indicates that the device has provided two oranges A and B.

(24) FIG. 3f shows the moment at which the line 2 continues to advance such that the beam 6 of light detects the gap 7 between the third orange C and the fourth contiguous orange D in the line 2. The graph shows how the intensity (I) value detected is again lower than the predetermined threshold (Ith) value.

(25) FIG. 3g shows the moment at which the line 2 continues to advance such that the beam 6 of light detects the fourth orange D in the line 2. At this instant, the graph again shows an intensity (I) value that is higher than the predetermined threshold (Ith) value. As a result, the detection means 5 count a third space, which indicates that the device has provided three oranges A, B and C.

(26) Likewise, due to the fact that the predetermined number of oranges, three oranges in this example, has now been reached, it may be seen how the retention means 4 are again actuated, stopping the fourth orange D from passing through, thus interrupting the advance of the line 2.

(27) It is also worth noting that in this example the striking point of the detection beam 6 is arranged upstream from the retention means 4. This ensures that when the predetermined number of oranges has been reached, the retention means 4 can act immediately to retain the next orange, which then becomes the first orange in the line 2 to begin a new sequence.

(28) With reference to FIGS. 1 and 4, the retention means 4 comprise a gripper 8 provided with flexible fingers capable of adapting to the contour of the first orange A in the line 2. In particular, it is envisioned that a gripper with Fin Ray Effect technology or similar will be used, as it enables flexible gripping of objects having a variety of shapes.

(29) According to a preferred embodiment, the gripper 8 is mounted on the end of a pivoting support 9 that is actuated by means of a connecting rod and crank mechanism, the crank 10 being articulated at one end to the pivoting support 9 at a point near to the gripper 8 and at the other end to the connecting rod 11, and said connecting rod 11 being actuated by an electric motor 12, such that when the motor 12 rotates in one direction, the gripper 8 is capable to be raised, allowing the line 2 of oranges A,B,C,D,E,F,G to advance along the chute 3, and when the motor 12 rotates in the opposite direction the gripper 8 is capable to be descended until entering into contact with the first orange A in the line 2 to retain it in the chute 3.

(30) The motor 12 is a motor with torque control and with the ability to regulate the upward and downward paths of the gripper 8, whose stroke will depend on the size of the oranges A,B,C,D,E,F,G supplied in the chute 3.

(31) To carry out an initial calibration of the motor, it should be borne in mind that the starting point of work corresponds to the fingers of the gripper 8 touching the chute 3, i.e. in the lowest position. Next, the gripper 8 is raised for the first time by a rotation angle of 9. If the orange A passes under the gripper 8, the work cycle will continue; otherwise the gripper will be raised another 9, and so on until the first orange A passes through without interruption. The time that the gripper 8 is up is the time that the predetermined number of oranges to provide need in order to pass through.

(32) Next, the gripper 8 is lowered for the first time until it meets an orange, controlled by the motor's 12 detection of the maximum torque set. The second time the gripper 8 is raised, it again raises 9 with respect to its prior position. In the same way, the time that the gripper 8 is up is the time needed to let through the predetermined number of oranges to provide.

(33) Thereafter, the gripper 8 is lowered a second time until meeting an orange, in the same way as the first time it is lowered, and the work cycles repeat in this way successively.

(34) Furthermore, the chute 3 has a tilt greater than 4 to ensure that the line 2 of contiguous oranges A,B,C,D,E,F,G moves at a suitable speed along the chute 3, taking advantage of the fact that said oranges can be counted very quickly and effectively. It has been found that the optimum tilt value is 8.

(35) Likewise, as can be seen in FIG. 1, the chute 3 is provided with vibration means 13 to help the line 2 of contiguous oranges A,B,C,D,E,F,G move along the chute 3, keeping it from getting jammed. Said vibration means 13 are adapted to deliver a vibration of at least 5 millimeters of amplitude with a frequency of more than 40 Hz, thereby optimizing the speed at which the line 2 of contiguous oranges A,B,C,D,E,F,G moves along the chute 3.

(36) Now making reference to FIG. 5, the invention also relates to a combination weighing machine 20 comprising a plurality of said devices 1 for providing fruit and vegetable products, such as oranges in this example, said machine 20 being provided with control means 21 adapted to, among other parameters, indicate the number of oranges that should be provided to a bucket 22.

(37) The machine 20 further comprises a transport system that continually moves a series of carriages 23 along a closed path that comprises a straight top section, a straight bottom section, and two curved sections linking said top and bottom sections, such that each carriage 23 holds several buckets 22. Moreover, it includes a series of work stations distributed all along the path followed by the buckets 22, in particular, a loading station 24 for loading oranges A,B,C,D,E,F,G to provide to the buckets 22, a weighing station 25 for weighing the buckets 22, arranged on the top straight section of the path followed by the carriages 23, and a selective unloading station 26 (not shown in FIG. 5) for unloading the oranges loaded in the buckets 22, arranged on the bottom straight section. Likewise, the control means 21 process the weighing data and select the buckets 22 whose total weight is closest to a predetermined value for unloading.

(38) According to the embodiment shown in FIG. 5, it is envisaged to place two devices 1 connected to the same bucket 22. In this way, the number of oranges provided to each bucket 22 is duplicated, thereby optimizing the production time of the machine 20.

(39) FIG. 6 is a more schematic illustration of this particular ordering of the devices 1 in the machine 20, specifically to be able to supply products to a same bucket 22 using two chutes 3, each one of which is associated with emission and detection means 5 of the beam 6 of light and with retention means 4.