GB747558A - Improvements relating to the sorting and counting of packages - Google Patents

Abstract

747,558. Sorting packages photo-electrically. BRITISH THOMSON-HOUSTON CO., Ltd. Feb. 24, 1954 [Feb. 16, 1953], No. 4252/53. Class 40 (3). Packages on a conveyer are sorted by producing for each package a group of electrical impulses proportional in number to the length of the package, counting the impulses produced in each group and counting the undivided groups of impulses having the same number. As shown, the packages 2, 3 are carried on a conveyer 1 and the pulses are produced by a chopper plate 6 driven by the conveyer and interrupting the light incident on a photoelectric cell 7. The arrival of a package at a receiving station is detected by a second photoelectric cell 9 which then opens a " gate " so allowing the pulses produced by cell 7 to pass to an electron counter comprising stages 13, 14, 15 and at the same time holding the shield grids of thyratrons T1 to T5 negative. The counter may be as. described in Specification 704,816, [Group XIX], and comprises three stages arranged on the decimal system so that the count can be one of three figures, each impulse representing a conveyer travel of one millimetre. All stages other than the units stage are provided with selector switches which may be set to give three or more numbers representing three possible sizes of package. In operation when the number of pulses representing the smallest package has been counted the counter operate a coincident circuit 16 to move the discharge path of an electronic counter tube 17 from zero cathode to cathode number one. The cathode load develops a voltage which conditions a first thyratron T1 which does not fire until the package has passed cell 9 when the gate 11 closes and the negative potential is removed from the thyratron shield grid. If this does not happen the counter continues to count the pulses until the next setting of the counter circuit is reached when coincident circuit 16 moves the discharge path in tube 17 to cathode T2 restoring thyratron T1. If now the end of the package passes cell 9 thyratron T2 fires operating its counter C2. Relay 19 is also energized and contacts with relay 21 to remove the anode potential from the thyratrons. A time delay relay 23 is provided to prevent anode potential being applied to the thyratrons until they have been heated. The Specification states that the thyratrons may be used to sort the article by impressing their output signals on a magnetic disc driven from the conveyer so as to operate on the electrohydraulic device by means of a pick-up situated around the disc, thus introducing a time lag to allow the article to reach the appropriate receiving bin.