Patent GB-447583-A (GB)
Title: A machine for grading eggs
IPC: G01N33/08
Filed: 1935-06-28
Abstract: 447,583. Testing eggs. BURGESS, A. F., 10, New Court, Lincoln's Inn, London.- (Kraft Egg Machine Co. ; 400, Rush Street, Chicago, U.S.A.) June 28, 1935, No. 18605. [Class 28 (ii)] [See also Group XIX] Eggs are graded as regards quality by employing the principle that in a deteriorated or partly deteriorated egg, the white, instead of being sufficiently stiff to retain the yolk in a central position, is thin and watery and, hence, will permit the yolk, which is lighter than the white, to rise against the upper part of the shell. A device for giving a relative indication of the vertical position of the yolk is shown, and comprises an egg support 11, a lamp 26 with a condensed or concentrated filament 27, openings 33, 34 which admit light only to zones of the egg lying between the yolk and the shell, and a photoelectric cell 28 which is influenced by light reflected from the inside of the egg shell, and from the surface of the yolk, through an opening 35 in the casing 32 enclosing the cell. A micro-ammeter M and amplifier O are disposed in the circuit of the cell 28. The yolk of a fresh egg is disposed centrally as at A, and light reflected from the inside of the shell to the cell 28 not obstructed by the yolk. In a deteriorated egg, however, the yolk is in a higher position and is somewhat distorted as at B, the reflected light then being partially obstructed by the yolk and the reading of the micro-ammeter M is varied accordingly. The reading of the instrument M thus gives a relative indication of the position of the yolk and the corresponding quality of the egg. The egg-supports 11 are moved over a table 10 by a continuous chain 20 and are guided by a ledge 21. The egg rests on parallel inclined flanges 12, 13 and are positioned longitudinally by upstanding abutments 14, 15. The openings 33, 34 each have an inner flat side and a curved outer side. It is necessary to provide compensating means for the variation in the sizes of the eggs, and consequent variations in the sizes of the yolks. In the case of a large egg, the amount of light transmitted is less than that transmitted through a smaller one. Shutters 45, 46 are therefore arranged to move in a horizontal plane in opposite directions under the opening 35, and means are provided to open the shutters to a greater extent when testing a large egg. The opening 35 is formed with inwardly projecting points 38, 39, the opening of the shutters thus allowing a larger admission of light to the cell 28 than would result from the mere increase in the spacing of the shutters. The shutters are pivoted on shafts 43, 44 and are normally kept closed by a light spring 48, a stop 49 keeping them central. Downwardly depending roller-ended feelers 50, 51 on the shutters are pressed apart by the eggs, and the shutters are opened to an extent depending on the size of the egg. Means are provided for indicating whether a small, medium or large egg is in the test position, such means comprising an extension 54 of the shutter 45 carrying a contact 65 which, when a small egg is in the test position, closes with a contact 64 on a spring arm 57, the contact 62 on the spring arm 58 still touching the contact 63 on the arm 57. This causes the lamp 68 to light up. A medium egg will displace the shutter 45 sufficiently to close the contact 63 with the opposed contact on the spring arm 56, the arm 58 following the movement and keeping the contacts 62, 63 closed. A medium egg will thus cause both lamps 67, 68 to light. With a large egg, the following motion of the arm 58 is arrested by a stop 61, and the lamp 67 only is lighted.