Patent GB-426555-A (GB)
Title: Improvements in and relating to apparatus for testing and sorting electrically conducting parts or packages
IPC: G01N27/72
Filed: 1933-09-30
Abstract: 426,555. Magnetic &c. separators. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London.- (Assignees of Moore, A. J. ; 40, Bridge Street, Melrose Highlands, Massachusetts, U.S.A.) Sept. 30, 1933, No. 26947. Convention date, Sept. 30, 1932. [Class 72] [See also Group XXXVI] In an apparatus for testing and sorting electrically conducting parts or packages, the parts &c. 24 in a container 25 are fed on to, and retained between projections 23 thereon, a conveyer 10 and conveyed between the ends 28, 29 of an electromagnet 26 provided with a coil 30 which forms one arm of a Wheatstone bridge circuit the other three arms consisting of a variable inductance 31, a variable resistance 32 and a fixed resistance 33, the bridge being connected to an alternating current source 34. The difference in potential across the bridge circuit, caused by an unbalance thereof, is impressed on a resistance 35 and a direct current milli-voltmeter 36, both of which are across points 37, 38 of the bridge circuit, a full wave rectifier 39 being interposed to convert the alternating into direct current. The grids 43 of two electron discharge tubes 40, 41 are connected to predetermined points in the resistance 38, the anode 44 of the tube 40 being connected in series with a relay 49, provided with normally open contacts 50, to the right hand terminal of the secondary winding of a transformer 46, and the anode 44 of tube 41 also being connected by a relay 51, with normally closed contacts 52, to the secondary 48. The filaments 42 are connected across a few turns of the secondary 48 as well as to the resistance 35 and the ground at 53. A relay 54 is connected in between contacts 50, 52 to the source 34 and is connected through contacts 55 with the source 34 and also by the strip 61 and contact 62 to the coil 60 of a solenoid 58, the core of which is connected to a rod 56 which passes through an aperture in the arm of the electromagnet 26. The other end of the coil 60 is connected to the source 34. The strip 61 is adapted to be moved in contact with the contact 62 by the engagement therewith of the driver 15 of a Geneva gear drive 14 which moves the conveyer a predetermined amount and then remains stationary for a predetermined period after each advance. When it is desired to deal with packages 24 containing five razor blades as the normal amount, the bridge circuit and the connections from the grid 43 to the resistance 35 are so adjusted that when a normal package is fed between the ends 28, 29 of the magnet 27, the grid bias voltage of the tube 41 is such that insufficient current flows through the relay 49 to effect its operation so that the contacts 50 remain open and similarly the contacts 52 will be opened. The relay 54 will have its contacts open and so when the driver 15 moves around so that pin 19 presses the strip 61 against the contact 62 the circuit of the coil 60 will remain open and the package will not be ejected from the conveyer. If the package contains less than 5 blades the contacts 52 will be opened and the contacts 50 and 55 will be closed so when the pin 19 in its movement presses the strip 61 against the contact 62 the circuit of the coil will be completed and the package will be ejected from the conveyer by the forward movement of the rod 56. If the package contains more than five blades the contacts 50 will be open and the contacts 52, 55 closed. The circuit of the coil will again be closed and the package ejected from the conveyer by the rod 56. The parts &c., may also be tested and sorted in accordance with their magnetic permeabilities, with their chemical compositions or with their mechanical dimensions in the latter two cases by the difference in their electric resistances by adjusting the bridge circuit and the connections from grids 43 to the resistances 35. The conveyer may be dispensed with and then the article is placed between the parts 28, 29, and the strip 61 depressed by hand.