Patent GB-1009847-A (GB)
Title: Improvements in or relating to oscillographic recorders
IPC: G01D15/14
Filed: 1962-01-24
Abstract: 1, 009, 847. Recording-apparatus; galvanometers. HONEYWELL Inc. Jan. 24, 1962 [Jan. 31,1961], No. 2649/62. Headings G1J and G1Q. In recording-apparatus having a beam of radiant energy focused to a point on a moving paper P and moved laterally of the paper by a reflecting galvanometer 26 responsive to a variable to be recorded, the paper is sensitive to wavelengths in the radiant energy beam whereby an immediately visible trace is produced on the paper, the paper has maximum response to ultraviolet light and the source of the radiant energy beam is an incandescent electric lamp 18 having a tungsten filament and a quartz envelope. The lamp. Operating at from 40 to 70 watts the tungsten filament of the quartz-iodine lamp 18 serves as a source of radiation including wavelengths of 4700 Angstrom units and shorter and the quartz envelope transmits ultra-violet light. Spring clips 17 ensure good electrical contacts and the lamp housing 14 is ventilated by a cooling fan 11. The optical system. Rays from the lamp 18 are collected by a quartz lens 19, which is a cylindrical crossed positive-negative reducing collector lens, and then pass through a piano cylindrical galvanometer lens 54 and fall on the galvanometer mirror 49 for reflection thereby. The focal length of the lens 54 is selected so as to focus, in the lateral plane, at the plane of the paper P. A mirror 55 has a surface following a curve which is part of an ellipse and provides a focus at the plane of the paper P in the longitudinal sense. The Galvanometers. Six galvanometers 26 having a natural frequency of forty-two or of three hundred and thirty cycles per second are mounted so as to extend into an opening in a C- shaped magnet 25 and their coils are fed with the voltages to be recorded. The case 27 and suspension for a coil 44 and mirror 49 of one of a number of galvanometers 26 are described in great detail with reference to Figs. 2 to 7 (only Fig. 4 shown). Pole pieces 28 of sintered iron are cast integrally in the case 27 which is made of aluminium or other non-magnetic metal by investment casting. A number of turns of fine wire pass round bobbins 43, 45 to form the coil 44, enamelled copper and enamelled aluminium being used for the coil to operate at 42 cps and 330 cps respectively. Upper and lower suspension ribbons 46, 42 pass through the bobbins 45, 43 and round bobbins 35, 41. The upper "bobbins" 35 may be an ivory flanged spool on a metal pin or a glass rod, in a slot in a shaft 32, the latter giving a resistance to voltage breakdown up to 1,000 volts. The mirror 49 is cemented to the upper suspension ribbon 46 and has a U-shaped bar cemented to its back to provide static balance in rotation and damping block 51, having two interconnecting conical holes holding oil, fits over the ribbon 46. Paper supply and drive. The end of a supply roll of paper on a shaft 62 within a housing 61 is passed out of an opening, under a drive roller 63 and out of the opening 5 in the case 1, a filter 65 preventing pre-exposure. The roller 63 is driven by a motor 57 through change-speed gearing 59, which provides for paper speeds up to 25 inches per second. Paper sensitive to radiation in the wavelength range 3000-4700 Angstrom units is suitable as the lamp 18 can produce sufficient energy in this range to produce a good trace. Mounting, focusing and operation. The collector lens 19 may be centralized in the aperture in in the lamp housing 14 by loosening the screws 191 of the clip 20 and moving the lens until the band of light covers the mirrors 49 both vertically and horizontally. For focussing purposes, the case 1 is opened and a translucent screen is held one and a quarter inches in front of the aperture 5. The best focus of the vertical bars of light from the mirrors 49 is obtained on the screen by loosening the screws 22 holding the magnet assembly and moving it backwards or forwards, if necessary the lens 19 can be adjusted backward or forward by loosening the screws 24 holding the lamp housing 14 on the frame 13. After tightening up the screws, the case 1 is closed and after loosening screws 251 the magnet 25 is rotated in the frame 21 about a horizontal axis until the brightest spots from the mirrors 49 are obtained in the writing plane of paper P. After locking the screws 251 the mirror 55 is adjusted vertically to obtain the best focus of the light spots at the writing plane. Power for the lamp 18 is supplied from the secondary winding of a transformer which is tapped so that different intensities can be selected -one below recording intensity and a "low" and a "high" recording intensity for use with "low" and "high" speeds of paper travel. Specification 883,516 is referred to.