Sorting machine

Claim 2

A semi-free-fall sorting apparatus for granular items, comprising: an elongated slide tapering downwardly to the diameter of said items and having a central longitudinal generatrix that is steeply inclined for gravity separation of said granular items sliding downwardly thereon, and for aligning said sliding items in serial order along a common path corresponding to said central generatrix; the upper end of said slide having a gently rounded bottom portion as seen in cross-section along the line of said central generatrix, the curvature radius of said bottom portion being substantially greater than the mean radius of said granular items; said slide tapering from upper to lower end so that the cross section along the direction of said central generatrix at the lower end displays a curved bottom portion of curvature radius substantially in the same order as said mean radius of said granular items; means for introducing said items in a random shower into the upper end portion of said slide; and means for examining and sorting said items aligned in said serial order.

Claim 3

An apparatus as recited in claim 1 wherein: saiD slide has spaced side walls extending from said curved bottom portion to define a U-shaped cross section at said upper end; said side walls being angled to converge downwardly toward one another to define a generally V-shaped cross section at said lower end.

Claim 4

Apparatus as recited in claim 1 wherein: said means for introducing said items to the upper end of said slide includes a vibrating tapered chute in the same vertical plane as said slide but gently inclined in the opposite direction so as to discharge said granular items into said slide with the least possible vertical component of velocity and a horizontal component of velocity oppositely directed to the horizontal velocity component that is to be induced in said items by said slide.

Claim 5

The combination recited in claim 3, wherein said apparatus also includes: a plurality of said slides and said examining and sorting means arranged in parallel and a corresponding plurality of said chutes also in parallel; said chutes extending from a common feeding tray mounted for vibration; motor and eccentric mass vibrating means mounted to vibrate said tray and chutes; and each of said chutes having an adjustable gate at the tray end thereof to equalize the flow rate of said items despite differences in the vibrating effect resulting from differences in the chutes and their distances from the vibrating means.

Claim 6

The combination recited in claim 4, wherein said apparatus also includes: stationary hopper means mounted above said tray for reception of said granular items; flexible coupling means between said hopper means and said tray; said hopper means, flexible coupling means and tray being arranged to define a closed conduit for said granular items from the entrance to said hopper means to the opening of said adjustable gates to said chutes.

Claim 7

The combination recited in claim 5, wherein: said slides are arranged in two criss-crossed banks; the chutes for said respective banks extending from opposite sides of a feeder tray and hopper means; said examining and sorting means being arranged in two corresponding banks beneath said slides.

Claim 8

The combination recited in claim 1, wherein said examining and sorting means includes; photoelectric viewing means disposed beside said path for viewing a zone of said path no longer than the mean length of said granular items in their sliding orientation with respect to said slide; at least two light sources disposed respectively above and below said photoelectric means along the length of said path; ejection means adjacent said path for selectively diverting said items therefrom upon signal from said photoelectric means; receptacle means on said path below said ejection means for receiving undiverted items; a third light source positioned on the opposite side of said path from said viewing means and shielded from said viewing zone; variable background means positioned adjacent said path directly opposite said viewing means and illuminated by said third light source and adjustable to induce a signal from said photoelectric means that is substantially identical to the signal induced by passage of the mid-portion of an acceptable one of said items; said ejection means being adapted to operate only when the signal from said photoelectric means differs appreciably from said background-induced signal; said background means including a flat-surfaced background uniformly colored in the same general color as said acceptable items; said background being rotatably adjustable about an axis abnormal to said flat-surface so as to deepen or lighten the apparent shade of said background as viewed by said photoelectric means, thus to induce said signal identical with that of an acceptable item.

Claim 9

The combination recited in claim 7 and adapted for the sorting of elongated gray-white rice grains as said items, wherein: said background is of generally gray-white color and is rOtatable to reflect light to said photoelectric means in the same intensity as an acceptable grain of said rice; said ejection means being calibrated to operate upon reception of a signal indicating a dark spot in one of said rice grains, said signal having a voltage amplitude level differing appreciably from that provided by said background.

Claim 10

The combination recited in claim 7, wherein: two of said viewing means are provided on opposite sides of said path for viewing opaque items; and four light sources are provided, one above each viewing means, and one below each viewing means; and two background means are provided, each aligned with one of said viewing means and said viewing zone.

Claim 11

The combination recited in claim 7, wherein said receptacle means for receiving acceptable undiverted items includes: a first elongated tube aligned on said path and having an opening in the upper side thereof; and a second elongated tube pivoted on the upper side of said first tube so as to cover said opening in a normal position of said second tube aligned parallel to said first tube; said second tube being pivotable to a sampling position wherein the upper end of said second tube intrudes through said opening into said first tube and diverts said acceptable items into said second tube for examination as a sample.