GB290073A - Improved method of and apparatus for detecting flaws or hidden fissures in metal bars, rails and the like - Google Patents

Abstract

290,073. Jackson, F. R., (Sperry Development Co.). July 22, 1927. Pens for recording-instruments.-In apparatus for detecting flaws in metal bars, rails, &c., a relay controls the circuit of a recording pen shown in Fig. 13, comprising an electromagnet 36 and a spring arm 37 which carries at its free end a U-shaped pen 38, the inner end of which dips into an ink trough 39. A series of such pens may be mounted adjacent to one another with the magnets staggered, as shown. The pens mark on a chart which is driven from the car wheels, so that the location of a flaw may be scaled off from the chart. A polarized recording pen is shown in Figs. 4 and 4<a>, in which a U-shaped magnet 120 is energized by a continuous current and a coil 42<1> is in circuit with or controlled by the amplifier. A spring plate armatures 122 pinned at its base projects through the coil 42<1> and between the ends of the U- shaped magnet, and has a pin 123 engaging a slot in the reed 125 which holds the pen 46<1>. A flaw causes motion in one direction, while bad or broken contact at the brushes causes motion in the other direction.