APPARATUS FOR SORTING FRUIT ACCORDING TO COLOR

• US 3,770,111 A
• Filed: 05/03/1972
• Issued: 11/06/1973
• Est. Priority Date: 05/03/1972
• Status: Expired due to Term

• Current Assignee: Charles S. Greenwood, Donald W. Chamberlin
• Original Assignee: Charles S. Greenwood, Donald W. Chamberlin
• Inventors: Greenwood, Charles S., Chamberlin, Donald W.
• Primary Examiner(s): Knowles, Allen N.
• Application Number:
  US05/249,925
• Time in Patent Office: 552 Days
• Field of Search: 250/227,220,223,226 209/111.6,111.7,73,74
• US Class Current: 209/580
• CPC Class Codes: B07C 5/342 according to optical properties, e.g. colour according to radiation transmittivity B07C5/3416
• CPC Class Codes: B07C 5/365 using a single separation means
• CPC Class Codes: Y10S 209/923 Feed through including at least one endless conveyor

Abstract

Apparatus for sorting fruit according to the color thereof includes a conveyor which is arranged to receive fruit in bulk, singulate the fruit into a randomly spaced arrangement, and transport the fruit through a sorting head to a discharge station where the fruit can be discharged to one of three locations in accordance with its color characteristics as determined by the sorting head. This head includes a plurality of lights for illuminating the surface of the fruit as it passes through the head and a ring spaced radially from said conveyor which is adapted to mount the inlet ends of a plurality of fiber light guides so that they define a cylindrical band. The outlet ends of the light guides are brought together into bundles to direct the light reflected from the fruit to two photodetectors. Signals from these photodetectors operate a pair of solenoids and a pair of associated air blast means at the discharge station to selectively tilt certain fruit off the conveyor.

Claims

1. Apparatus for sorting fruit according to color comprising a conveyor for carrying said fruit along a horizontal path, a sorting head extending around said conveyor through an angular distance greater than 180*, said sorting head comprising means for lighting the surface of said fruit on said conveyor as it passes through said sorting head, said sorting head further comprising a plurality of fiber light guides for receiving and transmitting light reflected from said fruit, said light guides having their inlet ends posItioned so as to define a narrow cylindrical surface extending circumferentially about said conveyor throughout the angular distance of said sorting head in a plane transverse to the direction of movement of said conveyor, and means downstream of said sorting head for discharging said fruit from said conveyor in accordance with the characteristics of the light received and transmitted by said light guides, said sorting head including means forming a narrow circumferential slit through which the light reflected from said fruit must pass before being received by said light guides, said slit being spaced radially inwardly from said surface defined by the inlet ends of said light guides.

2. Apparatus for sorting fruit according to color as set forth in claim 1 wherein the outlet ends of said light guides are brought together into at least one bundle, a heat conducting block for receiving and enclosing said bundle of light guides, a solid state photodetector mounted within said block adjacent said ends of said light guides for receiving the light transmitted thereby and for providing an electrical output signal in accordance with the intensity thereof, and means for heating said block to a constant temperature.

3. Apparatus for sorting fruit according to color as set forth in claim 2 including an optical filter positioned in said block between the ends of said light guides and said photodetector.

4. Apparatus for sorting fruit according to color comprising a conveyor for carrying said fruit along a horizontal path, a sorting head extending around said conveyor through an angular distance greater than 180*, said sorting head comprising means for lighting the surface of said fruit on said conveyor as it passes through said sorting head, said sorting head further comprising a plurality of fiber light guides for receiving and transmitting light reflected from said fruit, said light guides having their inlet ends positioned so as to define a narrow cylindrical surface extending circumferentially about said conveyor throughout the angular distance of said sorting head in a plane transverse to the direction of movement of said conveyor, and means downstream of said sorting head for discharging said fruit from said conveyor in accordance with the characteristics of the light received and transmitted by said light guides, said conveyor comprising a pair of narrow belts arranged in parallel relationship and adapted to support said fruit with each fruit being supported only at two points thereon on opposite transverse sides thereof, and means for delivering fruit to said conveyor in randomly spaced single file arrangement, said fruit delivery means comprising a fixed trough having outwardly diverging wall portions which extend upwardly from said conveyor, said trough being located upstream from said sorting head, means for delivering bulk fruit to the upstream end of said trough, said conveyor comprising a first section extending within said trough and a second section extending downstream from said first section and through said sorting head, and means for moving said second conveyor section at a greater linear speed than said first conveyor section.

5. Apparatus for sorting fruit according to color as set forth in claim 4 wherein both of said first and second conveyor sections are comprised of spaced parallel belts and wherein the spacing of the belts in said second section is less that of the belts in said first section.

6. Apparatus for sorting fruit according to color comprising a conveyor for carrying said fruit along a horizontal path, a sorting head extending around said conveyor through an angular distance greater than 180*, said sorting head comprising means for lighting the surface of said fruit on said conveyor as it passes through said sorting head, said sorting head further comprising a plurality of fiber light guides for receiving and transmitting light reflected from said fruit, said light guides having their inlet ends positioned so aS to define a narrow cylindrical surface extending circumferentially about said conveyor throughout the angular distance of said sorting head in a plane transverse to the direction of movement of said conveyor, means downstream of said sorting head for discharging said fruit from said conveyor in accordance with the characteristics of the light received and transmitted by said light guides, said fruit discharge means being arranged to either permit said fruit to remain on said conveyor or to dislodge it therefrom to one side or to the other of said conveyor, first and second fruit collecting means positioned on opposite sides of said conveyor to receive discharged fruit, and a third fruit collecting means at the downstream end of said conveyor to receive discharged fruit whereby said fruit can be sorted into at least three separate color grades by said apparatus, said fruit discharge means comprising a pair of selectively operable solenoid-operated plungers arranged to move in a vertically upward direction when energized to engage the bottom portion of a fruit and tilt it off the conveyor, said plungers being arranged at opposite sides of said conveyor.

7. Apparatus for sorting fruit according to color as set forth in claim 6 wherein said fruit discharge means further comprises a pair of pneumatic means positioned above said plungers for selectively directing air blasts at said fruit to further aid in the discharge thereof.

8. Apparatus for sorting fruit according to color as set forth in claim 6 including sensing means for determining when an energized plunger has reached its full stroke, and means responsive to said sensing means for returning said energized plunger to its retracted position immediately after it reaches its full stroke.

9. Apparatus for sorting fruit according to color comprising a conveyor for carrying fruit along a horizontal path, a sorting head surrounding said conveyor along a portion of said path and including means for lighting the surface of said fruit on said conveyor, said sorting head further including means for detecting the light reflected from said fruit, means for delivering fruit to said conveyor so that said fruit is singulated in a randomly spaced arrangement, means spaced downstream of said sorting head for discharging said fruit from said conveyor in accordance with the characteristics of the reflected light received by said light detecting means, and means positioned adjacent said fruit discharge means for detecting the presence of a fruit so as to render said discharge means operative, said fruit discharging means being operatively connected to said means for detecting the light reflected from said fruit and to said means for detecting said fruit adjacent said discharge means in order to permit said apparatus to sort randomly spaced and randomly conveyed fruit with discharge at a position spaced from said sorting head.

10. Apparatus for sorting fruit according to color as set forth in claim 9 wherein said fruit discharge means is arranged to either permit said fruit to remain on said conveyor or to discharge it therefrom to one side or to the other of said conveyor, first and second fruit collecting means positioned on opposite sides of said conveyor to receive discharged fruit, and a third fruit collecting means at the downstream end of said conveyor to receive discharged fruit whereby said fruit can be sorted into three separate color grades by said apparatus.

11. Apparatus for sorting fruit according to color as set forth in claim 10 wherein said conveyor comprises a pair of spaced parallel belts and wherein said discharge means comprises a pair of selectively operable solenoid-operated plungers arranged to move in a vertically upward direction when energized to engage the bottom portion of a fruit and tilt it off the conveyor, said plungers being arranged between said belts at opposite sides of said conveyor and adjacent to said means for detecting the presence of a fruit.

12. Apparatus for sorting fruit aCcording to color as set forth in claim 11 wherein said discharge means further includes a pair of open-ended tubes positioned on opposite sides of said conveyor and above and outwardly of said conveyor in positions adjacent to said means for detecting the presence of a fruit, and means for selectively supplying compressed air to said tubes to aid in discharging a fruit from said conveyor.

13. Apparatus for sorting fruit according to claim 11 including sensing means for determining when an energized plunger has reached its full stroke, and means responsive to said sensing means for returning said energized plunger to its retracted position immediately after it reaches its full stroke.

14. Apparatus for sorting fruit according to color as set forth in claim 13 wherein said sensing means comprises a member movable with said plunger, and a light detecting means actuated by the positioning of said member when said plunger is at full stroke.

15. In an apparatus for sorting fruit according to color which apparatus includes means for passing fruit in single file along a pathway and means operative in response to the amount of light reflected by said fruit for selectively discharging said fruit from said pathway, a sorting head comprising means for illuminating all side surfaces of said fruit as it is passed along said pathway, a ring mounted in said sorting head and encircling said pathway at the location where said fruit is illuminated, a plurality of fiber light guides mounted in said ring for receiving light reflected from said fruit and having their inlet ends distributed uniformly about said ring so as to define a cylindrical surface radially spaced from said fruit in said pathway, the outlet ends of said light guides being brought together into at least one bundle, a light detecting means positioned adjacent to said bundle of outlet ends of said fiber light guides for measuring the light received and transmitted by said light guides and for providing an electrical output signal, shield means enclosing said inlet ends of said light guides and extending radially inwardly therefrom, said shield means being provided with a narrow cylindrically shaped slit which is spaced radially inwardly from said inlet ends of the light guides so that said light guides receive substantially only the light directly reflected from said fruit in a narrow transverse planar segment as the fruit passes through said ring.

16. In an apparatus for sorting fruit according to color as set forth in claim 15 wherein said slit has a width of less than 0.5 inches.

17. In an apparatus for sorting fruit according to color as set forth in claim 15 including a transparent cylindrical ring sealing said slit so as to prevent the contamination of said fiber light guides.

18. In an apparatus for sorting fruit according to color as set forth in claim 15 including means for encasing said outlet ends of said light guides and said light detecting means, and means for heating said encasing means to a constant temperature.

19. Apparatus for sorting fruit according to color comprising a conveyor for carrying said fruit along a horizontal path, a sorting head extending around said conveyor through an angular distance of substantially 360*, said sorting head comprising an enclosed structure including means for lighting all surfaces of said fruit on said conveyor as it passes through said sorting head, said sorting head further comprising a plurality of fiber light guides for receiving and transmitting light reflected from said fruit, said light guides having their inlet ends positioned so as to define a narrow cylindrical surface extending circumferentially about said conveyor throughout the angular distance of said sorting head in a plane transverse to the direction of movement of said conveyor, means downstream of said sorting head for discharging said fruit from said conveyor in accordance with the characteristics of the light received and transmitted by said light guides, said conveyor compriSing a pair of narrow conveyor belts arranged in parallel relationship and adapted to support said fruit with each fruit being supported only at two points thereon on opposite transverse sides thereof with said fruit being able to translate freely on said belts while said belts carry the fruit through said sorting head, and means for shielding said inlet ends of said light guides from direct illumination by said means for lighting the surfaces of said fruit.