GB734481A - Improvements in or relating to apparatus for hardness testing - Google Patents

Abstract

734,481. Magnetic tests. MINISTER OF SUPPLY. Oct 20, 1949, No. 27012/49. Class 37. [Also in Group XXX] Articles to be sorted in accordance with their hardness are passed through a magnetic field and a reversed magnetic field, their residual magnetism controlling sorting mechanism. The articles, e.g. armour-piercing bullets, are fed in succession into a non-magnetic tube 4, Fig. 6, and, falling under gravity pass into the field of an electromagnet 7 ; after making a few heavily damped oscillations, the article is held between the pole-pieces until the electromagnet is deenergized ; the article then falls through a constantly energized solenoid 8 providing a reversed field; a search coil 9 located within the solenoid 8 is energized in accordance with the residual magnetism of the object and actuates a relay controlling a shutter 11 to permit the article to fall into an " accept " bin or deflect it into shoot 12 to the " reject " bin. The electromagnet 7 is energized by contacts on the article-feeding mechanism. Bullets to be tested are dropped into a hopper 13, Fig. 3, in which a disc 15 having circumferential grooves 16 rotates ; the disc 15 is protected by a fixed disc 19 from the weight of the bullets not in the grooves ; the disc is continuously rotated and carries the bullets to a shoot 14, a shutter 20 being reciprocated by arm 21 to allow the bullets to fall into shoot 14 ; the shoot has jaws 23, 24, Fig. 4, which compel the bullet to fall nose first into a portion of the shoot having a leaf spring 25 which holds the bullet until the reciprocation of arm 21 withdraws the spring and allows the bullet to fall ; the bullets thus all fall from the same position to give uniform testing conditions.