Patent GB-797157-A (GB)
Title: Apparatus for gauging and inspecting glassware
Filed: 1956-03-19
Abstract: 797,157. Electric measuring and control systems. OWENS-ILLINOIS GLASS CO. March 19, 1956 [April 5, 1955], No. 8425/56. Class 40 (1). [Also in Group XL (b)] Apparatus for examining glass jars for size and for flaws comprises feeler gauge members associated with the core of a differential transformer for measuring the diameters and light utilizing equipment for examining the surfaces for cracks &c. The jars 15 (Fig. 2) are transferred from a conveyer on to a rotatable pad 16, and lifted into the test position where they are held by a centring cone 20 and rotated during the testing cycle. Dimension gauging.-The appropriate diameter of the jar is engaged by two spring- biased rollers 21 (Fig. 11) mounted on arms 22, carrying the windings and the core respectively of a differential transformer 35. The core is initially adjusted to balance the two opposed secondary windings for a standard dimension, and deviation therefrom is shown in magnitude and direction by the transformer output signal, which is eventually indicated on a meter M (Fig. 13). When the deviation exceeds predetermined tolerances in either direction, the output signal is used to energize a reject mechanism. Flaw inspection.-A light beam from a lamp 36 (Fig. 2), passes vertically through con. denser lenses in a cylinder 43 on to a prism 51 where it is reflected horizontally through a channel 53 and through the rim of the jar 15 on to a central prism (not shown) which reflects the beam vertically through filters 66 to a photo-multiplier (not shown). The photomultiplier gives a pulse output for any irregularity in the jar rim, which is used to operate the reject mechanism. Two or more light systems may be used, examining the jar with diametrical, perpendicular or parallel beams. Control circuit, (Fig. 13).-The primary winding 35a of the gauging transformer 35 is energized from the right-hand half of valve VI, connected as an oscillator, via valve V2 and transformer T2. The output from the opposed secondary windings 100, 101 is fed through potentiometer 102, valve V4 and transformers T3, T4 to demodulator valves V5, V6, which are also fed directly from oscillator V1, via transformer T5. The resulting D.C. output is indicated on meter M in magnitude and direction, and is also fed to bi-stable multivibrator valves V7, B8 associated, together with the flaw inspection apparatus, with the reject mechanism. When a flaw is observed by the light beam, photo-multiplier 55 produces a negative pulse which is fed to the normally conducting half of valve V12, also acting as a bi-stable multivibrator, to make it change over, the level of the change-over pulse being determined by potentiometer 99. Thus a dimensional error outside the tolerances predetermined by potentiometers 112, 113 causes valve V7 or V8 to change over, and the presence of a flaw causes valve V12 to change over, in each case producing an increase in anode current since the new anode circuit has no dropping resistor, the combined anode currents passing through a transformer T6. Changeovers at valves V7, V8, V12 are also indicated by neon lamps 128, 127, 126 respectively. At the end of the gauging period an H.T. switch 82 is opened, breaking the anode circuits, the change in flux in T6 producing a positive pulse which is fed to valve V15, acting as a one-slot multivibrator, to cause it to change over if a fault had been located, for a time determined by potentiometer 120. At the end of this period V15 changes back, and the resultant increase in potential at its anode 130 is fed to trigger valve V 19, causing it to fire, energizing a counter 87, and a solenoid 88 which causes the appropriate jar to be rejected.