| 摘要 |
974,335. Photo-electric defect detection JONES & LAUGHLIN STEEL CORPORATION. Oct. 23, 1961, No. 37921/61. Heading G1A. [Also in Division G4] In a system for detecting surface imperfections, for example in sheet tin, the material 10 Fig. 1 is conveyed past a photo-electric sensing arrangement 16, 20 which responds to the different reflective properties of imperfect as opposed to perfect surfaces and the resulting electric signal, if of a sufficient amplitude, (i.e. if the transverse dimension of the imperfection 14 is sufficiently large) opens a gate 26 to allow pulses produced by the motion of the material to pass to a defect counter 34. The defect counter is reset to a predetermined number (e.g. 15,000) at 5 feet intervals by a displacement counter 30 and is stepped backwards by the defect representing pulses so that it only reaches zero, to produce an output, if the area of surface imperfection in a 5 feet length of material exceeds a certain amount. The output from the defect counter can either cause a faulty strip of material to be rejected or it can control a printing device. The Specification also mentions that hot strip could be inspected by the same system using the radiation from the strip itself instead of reflected light. |
