GB759196A - Method and apparatus for measuring thickness - Google Patents

Abstract

759,196. Linear dimension gauges; recording apparatus. BRITISH CELANESE, Ltd. Feb. 10, 1955 [Feb. 12, 1954], No. 4200/54. Classes 106 (2) and 106 (4). An apparatus for measuring and recording the variation in thickness of sheet material 69 comprises a stationary thickness gauge 76 having a movable foot 18, a stationary anvil 13 towards which the foot is urged, gauge and anvil being secured rigidly in relation to each other, advancing mechanism 1, 5-9 for forwarding the sheet 69 between the foot and the anvil, advancing mechanism for forwarding the strip 29 of recording material and means 24, 25 for recording variations in the displacement of the foot 18 from the anvil 13 on the strip 29, the advancing mechanism being geared to one another so that the motions of the sheet 69 and of the strip 29 are related. A motor 67 rotates a shaft 66 which through a crank pin 68 causes the rod 8 to oscillate the arm 7 which is spring loaded by a spring 9. A pawl 6 on the arm 7 engaging a ratchet wheel 5 causes the drum 1 to turn through a small distance at each oscillation of the arm 7. At the same time a crank pin 61 rotates about the shaft 66, causing the oscillation of arms 34 and 49 by means of pullcords 56 and 53. The arm 49 causes the intermittent advance of a reel 40 the teeth of which engage perforations in the recording strip 29, a ratchet wheel 47 mounted on the spindle 48 carrying the reel 40 being actuated by a pawl 46 carried by the arm 49. With each movement of the drum 1 a fresh part of the sheet 69 is gauged between the anvil 13 and the foot 18. The gauge 76 has a pen 24 on an arm 25 attached to its spindle. The timing of the respective oscillations of the arms 7 and 34 is such that when the arm 25 is steady the strip 29, backed by a plate 35, is moved by the arm 34 into contact with the pen to record any deviation in the thickness of the corresponding point on the sheet 69. As the cords 56 and 53 lead off from the pin 61 at right angles the strip 29 is not advanced while in contact with the pen 24. An attachment 26 frees the sheet 69 from static electricity by passing it between pads 27, 28 impregnated with a de-electrifying solution. Means are also incorporated to remove dust from the sheet 69, e.g. an electric fan. The relative speeds of sheet and strip may be adjusted.