The need to sort various types of objects in accordance with size, color and the like has been recognized for many years. This need exists since the size or the color of an object in many instances indicates its value or its suitability for some particular purpose. The need for some type of sorting apparatus has been adequately recognized in such fields associated with agriculture where there was a requirement for sorting out a particular type of product to determine its value or whether or not it was suitable to meet requirements for canning or other purposes.
For instance, when edible seeds such as navy pea beans, great northerns, sesame seeds, sunflower seeds and coffee beans are sent to the consumer, they are ranked by a government insepector as to the uniformness of their quality. Consumer preference is for a product virtually free of discolored, shriveled or split seeds. When the seeds arrive at a grain elevator from the farmers of the surrounding countryside, not only are these "bad" seeds present, but also mudballs, rocks and some other plant material. These latter undesirable materials may be to a large degree removed by a shaker--a sort of large sieve. The output of the shaker is basically all seeds but it contains both good as well as bad seeds. In order to improve their product and so command a higher market price, either the elevator company or packagers have to separate the bad seeds from the good.
It has long been desirable to do this separation by a machine rather than by hand. A machine that would achieve this has to be able to recognize the difference between good and bad seeds, and to separate them into two groups at a speed great enough to handle the large volumes involved, and at a low enough cost to make it worthwhile.
Such a machine was designed and built by Everett H. Bickley (1888-1972) a mechanical engineer who lived in the Philadelphia area. First produced in the early 1930's, the Bickley Bean Sorter worked on a very simple principle. Beans were mechanically fed onto a conveyor belt that carried and aligned them in a single file to a sorting point. There a white light was focused on them, and the light reflected off of them was "read" by a photocell. Good beans reflected enough light to activate the photocell closing an electric circuit that opened an electromagnetic flapper valve. The open valve permitted air under pressure to divert the good beans into an accept bin, while bad beans continued straight into the reject bin.
At present, the Bickley Bean Sorter has an upper limit of about 30 beans per second per sorting point. At this decision speed it makes a good separation. The limiting factor of speed is the air rejection mechanism. The valve itself has a period of about 20 ms or 50 cycles per second. But the latex connector hose and the low pressure used, necessary because of the valve design, combine to decrease the rate at which beans can actually be sorted to the 30 per second level. Indeed, in order to obtain excellent separation, even slower speeds were used. Therefore, it was necessary to have as many as 32 sorting points on a machine and if large quantities of beans were to be sorted, many machines were required. The need for an improvement upon such sorting has also been previously recognized as indicated by U.S. Pat. Nos. 2,730,234 and 3,283,896 which disclose means for sorting beans, rice, coffee beans, peanuts and the like according to their color.
However, there is still a need for an improved sorting apparatus since the sorting apparatus disclosed in these patents and presently in use are inefficient and do not have the desired speed for sorting such articles.
The present invention overcomes the disadvantages present in previous and current article sorting apparatus and provides an article sorting apparatus that is efficient and rapidly sorts numerous types of articles.