US 3142383 A
Description (OCR text may contain errors)
July 28, 1964 J. J. BOYER momma FOR som'mc 4 Sheets-Sheet 2 Filed Jan. 6, 1961 kb R3 Mm m h l Q Q W JEAN JACQUES BUYER INVENTOR BY ffi AGENT July 28, 1964 .1. J. BOYER MACHINE FOR SORTING 4 Sheets-Sheet 3 Filed Jan. 6. 1961 ISA I l- JEAN JACQUES BOYER INVENTOR BY W AGENT Filed Jan. 6, 1961 y 28, 1964 J. J. BOYER 3 ,142,383
MACHINE FOR SORTING JEAN JACQUES BOYER INVENTOR BYWK AGENT 4 Sheets-Sheet 4 United States Patent Office 3,142,383 Patented July 28, 1964 3,142,383 MACHHIE FOR SORTING Jean Jacques Boyer, 196 Rue de Rivoli, Paris 1, France Filed Jan. 6, 1961, Ser. No. 81,025 Claims priority, application France Jan. 7, 1960 '7 Claims. (Cl. 209--82) This invention relates to a machine for sorting goods having different shapes and/ or sizes, like fruits, and being provided with an analyzer comprising a source of light, a photo-electric cell sensitive to light rays, a device permitting the goods to advance along a path between the source and the cell, and means controlled by the cell for diverting individual objects from this path.
On most of the known machines of this kind, the cell effects an on-or-oif action; this means that it activates the diverting or deflection means only when the ray is interrupted by the article passing thereby.
The present invention concerns a sorting machine in which the light beam is constituted by parallel rays at the moment when sorting takes place.
Other features and advantages of this invention become more readily apparent from the following description, reference being made to the accompanying drawing in which:
FIGURE 1 is a cross-sectional view of photoelectric analyzer diagrammatically illustrating the principle of the invention;
FIGURES 2 and 3 are circuit diagrams of a sorting machine according to the invention;
FIGURE 4 is a diagrammatic illustration of the sorting machine;
FIGURE 5 is an elevational view, partly in section, showing a stand for the apparatus; and
FIGURE 6 is a circuit diagram of a modification according to the invention.
As can be seen in FIGURE 1, a light source 1 is disposed at the focus Fe of a concave mirror 2, which constitutes a parabolic reflector. The rays omitted by this source and striking the parabolic surface are reflected in a parallel beam along its axis of symmetry XX. To prevent the emission of nonreflected rays, a central transverse shield 3 extends across the beam between the focus Fe and the opening 2a of a diaphragm 4, this shield providing a neutral central zone ZN free of rays and insuring that the beam is of annular cross-section. It is. emphasized that, if the shield conforms to the orthogonal projection of the smallest object OM to be sorted on a plane perpendicular to axis XX, unnecessary luminous flux is eliminated, thereby avoiding the need for a stronger cell which would operate efficiently only in a zone of instability.
If with regard to the requisite dimensions of the source, for instance an electric lamp, it is necessary to employ a reflector of a size considerably greater than the diameter of the luminous beam necessary for the sorting, it is advisable to reduce the aperture 2a of this reflector to obtain a minimum quantity of light. Thus the diaphragm 4 is set at an aperture which permits passage of a beam whose cross-section is slightly greater than the orthogonal projection of the larger object OM to be sorted on the plane perpendicular to axis XX. In this way the amount of light required to be transmitted to the cell is reduced to a minimum. For concentrating the beam of light, an identical parabolic mirror 5 is provided with a shield 6 and a diaphragm 7 identical to the shield 3 and diaphragm 4 described above. Over-exposure of the cell 8 must be avoided, which means that a uniform distribution of the luminous flux upon the cathode thereof is essential. Therefore, the cell is fixed, not at the focus Fe of the parabolic mirror 5, but forwardly thereof between the focus Fe and the aperture 5a in diaphragm 7. The cathode of this photo-electric cell is turned toward the apex of the parabolic reflector and is completely shielded from direct rays entering the aperture. To avoid saturation of the cell and to have it operate along the most favorable portion of its characteristic curve, it is necessary to reduce the spurious illumination and to limit the intensity of the beam to a minimum. Moreover, the colour of the projected light should correspond to the type of cell, in regard to the photoelectric sensitivity of the latter. If a cell is utilized that has its maximum sensitivity in the red zone of the spectrum it is advisable to choose a projector rich in light of this color. This is the case, for instance, with conventional germanium cells. To obtain the desired temperature, it is necessary to connect with each incandescent lamp a regulating device to permit variation of the luminous density and to modify the voltage at the terminals. This voltage should be controlled in accordance with that of the corresponding cell.
The machine diagrammatically shown in FIGURE 3 comprises four posts or stations A, B, C, D, two of which (A and B) are shown in detail in FIG. 3. Each station is provided with a light-beam projector 1A, 2 and 1B, 2 directed towards a respective photoelectric cell 8A, 8B, the cathode of which is located forwardly of the focus of each parabolic mirror 5.
The apparatus is fed through the electrical assembly 17a, 17b, D, CBA which is detailed in FIGURE 2.
The goods or articles (l1, 02 to be sorted by the apparatus are transported by a band conveyor 21 (partially shown) along the path transverse to the light beams.
In a manner explained hereinafter, the current. pro.- duced by each cell 8A and 8B controls the electromagnetic valves 12A and 12B, air jets, which respectively eject the selected article into the passages 22A, 22B.
As shown in FIGURE 2, current is supplied to the terminals 26 for feeding the primary windings of the transformers T1 and T2, the secondary windings of which supply electric current to the indirectly heated cathodes of vacuum tubes, to the lamps 1 and after passing across rectifiers S1 and S2 and filters F1, F2 to the DC. current circuits of the stations A, B, C, D of the apparatus. in the usual manner.
The photocell at each of these stations, e.g. the photocell 8a of station A shown in FIG. 2, supplies, current to the circuit comprising the resistors r1 and r2 and the parallel connection of r3 and r4 established through the potentiometer 15. The voltage across resistor r2 is applied to the grid of an anode-follower tube 16a whence the amplified voltage is fed to the grid of a cathode-follower tube 16b. The cathode circuit of the tube, 16b includes the voltage-divider network formed by the seriesconnected resistors r5 and r6 which determine the grid potential of the gas-filled electronic switch 10 which may be a thyratron or preferably, as shown in FIG. 2, a gasfilled tetrode.
A potentiometer 18 and a resistor r7 supply to the grid of the electronic switch 10 a voltage sufiicient to render the tube 10 conductive in the absence of a balancing potential drop derived from the network r5, r6, r7. Consequently the tube 10 becomes conductive only if the voltage due to the current passing through the, network r5, r6, r7 does not exceed the threshold determined by the potentiometer 18, i.e. when the cross-section of the article is large enough to obstruct the beam and reduce the output of the cell.
The anode circuit of the tube 10 comprises the coil 11 of a relay having a normally closed contact 11w and a normally open contact 11b. Across the terminals of the coil 11 is connected a, c pacitor 19.
When tube 10 is rendered conductive a current passes through the coil 11 and the relay is energized and closes contact 11b, which feeds an electromagnetic air-control valve 12A. However, contact 11a is now open causing extinction of the tube and switching off of the relay; owing to the capacitor 19, however, deenergization of the coil 11 is delayed and the air jet may blow across the path of the articles for a sufiicient time to effect diversion of an article which has actuated the electronic circuits.
With the aid of potentiometer 14 (FIG. 3) it is possible to vary the terminal voltage of the lamps 1 and to read this voltage on a suitable voltmeter. After having placed an article to be classified in the path of the beam, the voltage of the cell 8 can be adjusted by the use of the potentiometer 15 while being read upon a voltmeter.
The sorting stations A, B, C, D, are located successively along the path of the articles to be sorted (FIG. 4), the articles passing between the light-beam projectors 1 and the cells 8. These stations A, B, C, D, are disposed along a main conveyor 21. As long as the beam from each projector 1 impinges upon the respective cell 8, the balancing voltage will be greater than the threshold of the thyratrons. When an article travelling on the conveyor 21 is interposed between projector 1 and cell 8, it blocks a part of the beam, thereby reducing the current at the terminals of the cell, according to the size of the object. When the resulting balancing voltage becomes less than the threshold voltage of the corresponding switch 10, the latter energizes, for a very short time, the corresponding relay 11 which feeds a respective electromagnet 25A, 25B, 25C, or 25D. The latter then rotates a corresponding deflector or vane 24, for diverting an article 0 onto a respective auxiliary conveyor 22 located on one of the tables T.
Assuming that the thresholds of the thyratrons of stations A, B, C, D, are successively increasing, the object will continue its way on to transporter 21 until it reaches a station with a corresponding thyratron threshold. At this station it will be ejected onto the auxiliary conveyor.
If the article is smaller than the size corresponding to the most elevated threshold, the conveyor 21 ejects it at its exit end (FIG. 4).
The conveyors 22 of tables T, are composed of a number of discs 23, partially overlapping, and fixed at their centers to a chain (not shown) which leads them along a closed path. Thus the packer is not limited to a specific time for packing each article since an unpacked article merely returns to the packing position if passed over.
In FIG. 5 there is shown a stand for the apparatus which is fabricated from metal tubing 31. A cradle 32 is movable vertically on the stand and supports a receptacle 33in this instance a packing case-engageable by angle irons 34. The cradle is shifted by a pedal 35 working against a spring 36 which displaces the load between a high loading position and a low discharge position.
A continuous conveyor 37 passes between the arms of the cradle 32 in a position slightly higher than the discharge position of the cradle 32. The conveyor 37 is narrower than the horizontal distance between the angleirons so that the pedal 35 causes the cradle 32 to descend to lower a case onto the moving conveyor.
It is possible that the articles to be sorted are asymmetrical, as is the case with Portugese oysters. In this case, the evaluation of a single surface is insufiicient to permit an efiicient classification. To effect this, each analysing position may contain a number of assemblies (projector and cell) effective in different planes to permit the analyzing of various characteristic surfaces of the object.
For instance the station D of the apparatus shown in FIG. 4 has been provided with three groups of projectorcell assemblies. The beams of two projectors 2 2 are directed in perpendicular relationship in the horizontal plane while the beam of the third is vertical and perpendicular to the other two at their intersection. It is evident that a machine capable of sorting asymmetrical objects like these must be provided with similar assemblies for all stations.
The more projector-cell assemblies at each position, the more accurate will be the classification. It is evident that the cells (eg, 8 8 8 of each position must be connected in series (as shown in FIG. 6) to permit the output voltage to activate the corresponding switch.
What I claim is:
1. An apparatus for sorting articles comprising means forming a transport path for said articles; and at least one sorting station disposed along said path, said station including a first concave mirror having a focus; a source of light located at the focus of said mirror emitting part of its rays towards said mirror for reflection thereof into a substantially parallel light beam extending across said path; first shield means at said first mirror forwardly of said focus in the direction of said path for arresting the other rays emitted by said source; a second concave mirror disposed opposite said first mirror across said path concentrating the rays of said light beam at another focus; second shield means at said second mirror rearwardly of said other focus; photoelectric detector means adjacent said second mirror and located beyond said other focus in the direction of said first mirror for receiving rays reflected by said second mirror; circuit means controlled by said detector means for providing an output current in response to the interruption of said beam by an article of predetermined size displaced along said path; and deflecting means controlled by said output current for diverting said article from said path at least one of said shield means having a central, inner shield axially aligned with the respective mirror and an annular outer shield coaxial with said inner shield for defining an annular light beam impinging upon said second mirror.
2. An apparatus for sorting articles comprising means forming a transport path for said articles; and at least one sorting station disposed along said path, said station including a first concave mirror having a focus; a source of light located at the focus of said mirror emitting part of its rays towards said mirror for reflection thereof into a substantially parallel light beam extending across said path; shield means forwardly of said focus in the direction of said path for arresting the other rays emitted by said source; a second concave mirror disposed opposite said first mirror across said path concentrating the rays of said light beam at another focus; photoelectric detector means adjacent said second mirror and located beyond said other focus in the direction of said first mirror for receiving rays reflected by said second mirror; circuit means controlled by said detector means for providing an output current in response to the interruption of said beam by an article of predetermined size displaced along said path; and deflecting means controlled by said output current for diverting said article from said path, said circuit means comprising a gas-filled tube having a control grid and an anode; means for applying to said control grid at substantially constant voltage normally sufficient to render said tube conductive; further means for applying to said control grid in opposition with said constant voltage a voltage proportioned to the intensity of the light received by said detector means; a relay having a coil connected in series with said anode, a normally-closed contact in series with said anode and a normally-open contact in a further electrical circuit controlling said deflecting means; and a capacitor connected across said coil whereby de-energization of said relay is delayed.
3. Apparatus according to claim 2 wherein said concave mirrors are parabolic mirrors.
4. Apparatus according to claim 2 wherein said shield means include a central shield in the path of said light beam having a surface conforming to the projection of the smallest article to be sorted on a plane perpendicular to said beam.
5. Apparatus according to claim 2 wherein said shield means comprises annular opaque diaphragms forming openings of equal diameters for both mirrors, said diameter being somewhat larger than the largest dimension of the largest article to be sorted.
6. An apparatus according to claim 2 wherein said defiecting means comprises a nozzle for directing a jet of air across said path, a source of air under pressure and an electromagnetic valve controlled by said circuit means and interposed between said nozzle and said source.
7. An apparatus for sorting articles of different shapes and sizes, comprising means forming a transport path for said articles, and at least one sorting station along said path, said station including at least two first concave mirrors having intersecting optical axes extending across said path and respective foci along said axes; a respective source of light located at the focus of each mirror emitting part of its rays toward it for providing a substantially parallel light beam extending along the mirror axis; respective transverse shield means for arresting the other luminous rays emitted by each source; at least two second concave mirrors each located opposite a respective one of said first mirrors for concentrating at respective foci the rays of the respective light beams; photoelectric detector means adjacent each of said second mirrors and located beyond the focus thereof in the direction of its first mirror for receiving rays reflected by the second mirror; conductor means connecting said detector means in series; circuit means controlled by the series-connected detector means for providing an output current in response to the interruption of said beams by an article displaced along said path; and deflecting means controlled by said output current for diverting said article from said path.
References Cited in the file of this patent UNITED STATES PATENTS 1,921,862 Bickley Aug. 8, 1933 1,963,128 Geister June 19, 1934 2,054,320 Hanson Sept. 15, 1936 2,447,024 Metcalf Aug. 17, 1948 2,627,347 Powers Feb. 3, 1953 2,675,917 Powers Apr. 20, 1954 2,719,236 Soltis Sept. 27, 1955 3,001,079 Straub Sept. 19, 1961 FOREIGN PATENTS 790,265 France Sept. 2, 1935