GB408340A - Improvements in apparatus for measuring, indicating or recording the thickness of sheet paper and the like - Google Patents

Abstract

408,340. Linear - dimension gauges. DANNATT, C., 39, Marlborough Road, Stretford, Manchester, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Oct. 17, 1932, No. 29018. [Class 106 (ii).] Relates to apparatus for measuring the thickness of a continuous sheet of paper &c. of the type in which variations in thickness are measured by the variation in the inductance of a coil carried by a roller between which and a magnetic member the sheet is caused to pass, and comprises a particular construction involving a swivelling roller. The paper passes over a take off or receiving roller to a spaced leading or trailing roller passing over an intermediate steel polished roller 6. Disposed above the roller 6 is a cross frame member 7 guided on vertical members 8, 8<a> secured to the uprights 1, 1<a> of the frame. The member 7 has secured to its end bearing blocks 9, 9<a> for a leading screw 10 adapted to be rotated through gearing 12 from a handwheel 11. On the screw 10 is mounted a carrier 13 for a contact roller 14. The carrier is guided on horizontal rods 15. A lifting rod 16 is secured to the frame member 7 and is attached to a cable 17 passing over a pulley 18. Cables 20, 20<a> secured to the member 7 also pass over pulleys 21, 21<a> to balance weights 22, 22<a>. The carrier, Fig. 3, comprises a rectangular block 25 bored and screw-threaded at 26 to engage the screw 10. Extending into a vertical bore 28 is a plunger 29 provided with a collar 30 between which and the recessed mouth of the bore 28 is a coiled spring 31. The plunger is secured to a platform 32 constituted by a rectangular plate having depending side brackets 33, between which is connected a U-shaped pedestal 35 carrying journals for a steel shaft 36 provided with enlarged spaced polished cylindrical portions 37, 38. Interposed between the portions 37, 38 is a block 39 of insulating material apertured to receive a coil (not shown) mounted on a former loose on the shaft 36 so that the coil is magnetically interlinked with the roller portions 37, 38. The roller can thus swivel about a vertical axis to a limited extent. Suitable terminals are provided on the pedestal 35 to allow electrical connection to the coil. Springs 40, 41 are disposed between the capped ends of adjusting screens 42, 43 and recesses in the part 35. In the bridge, Fig. 5, to which alternating current is supplied through a transformer 54, a standard inductance 51 is arranged similarly to the coil 50 linked with the roller 37, 38. The other arms include resistances 52, 53. The detector arm of the bridge includes the input side of a rectifier system 55 formed by four dry-plate rectifiers connected in the Graetz connection, the output side being connected to a uni-pivot galvanometer 56. Variation in the thickness of the sheet will cause corresponding variations in the magnetic reluctance between the rollers.