Patent GB-424165-A (GB)
Title: Improvements in or relating to measuring appliances
IPC: G01G23/36
Filed: 1934-08-14
Abstract: 424,165. Weighing and indicating apparatus. BAUML, M., and BAUML, J., 37, Porzellangasse, Vienna. Aug. 14, 1934, Nos. 23438 and 23439. Convention dates, Oct. 3, 1933 and June 9, 1934. [Class 143] [See also Groups XIX and XXXVIII] A device for indicating the measurement value of measuring appliances or for the actuation of registering, indicating, or counting devices of measuring appliances, more particularly weighing machines, in which the measurement value is indicated by patterns of light and shade produced on a projection surface by the illumination, from one side, of a screen having transparent portions and moved by the measuring appliance is characterized by the screen being provided with a transparent or non-transparent area for each measurement unit of the measuring appliance, the said areas being stepwise staggered with respect to each other and each corresponding in width, in the direction of movement of the screen, to the width of the associated measurement unit, and by the rays passing through the screen being so screened off that only the projection of a transparent or non-transparent area, or, with transition values, of two adjacent areas, falls on a stationary screen or on a member sensitive to rays, if desired, by way of an optical system, so that the measurement value can be read directly on the screen and/or the transmission of the measurement value to a registering, indicating or counting device can be effected by a single current fluctuation in an optico-electrical manner. As shown in Figs. 1 and 2 in connection with a weighing machine, a cylindrical screen 12 rotated by the weighing mechanism is provided with rows of transparent areas 0-9 arranged in staggered formation and representing unit digit values. Other transparent areas O, I, II, &c. of elongated form represent the tens values and so on for higher denominations. The transparent areas are illuminated from within the screen 12. An optical system 13 is secured to the casing 11 and includes a ground glass strip 15 inscribed with the numerals indicated by dotted lines in Fig. 2, (the roman numerals indicating the tens denomination). On loading the machine the cylindrical screen 12 rotates according to the applied load and the relevant transparent areas are brought into register with the optical device so as to illuminate the relevant digits on the ground glass screen 15, the images of the transparent areas being magnified to give a clear indication. In a modification, wherein the numerals on the ground glass plate 15 are preferably omitted, and the illuminated areas thereof are used for setting up the indication on an auxiliary apparatus, rows of electric contacts 16, Fig. 3, are arranged on the casing, each opposing pair of contacts corresponding to a digit. The contacts for each denomination are arranged in circuit with an amplifier 17 and a relay 19. A units slide 22 coupled by a loose motion pin 27 to a tens slide 221 may be moved parallel to the rows of contacts by a crank 25. Each slide carries a photo-electric cell 24 adapted to bridge the opposing contacts. When the slides are drawn over the contacts a pivoted projection 36 carried by each slide actuates its rack 38 and pinion 39 and the latter transmits the movement to the registering, indicating or counting apparatus. In order to arrest the registering-apparatus at the correct indication the pivoted projections 36 are withdrawn from driving connection with their racks by the de-energization of a magnet, the circuit of which is opened by the relay 19 when the photo-electric cell reaches the illuminated area and delivers a single current impulse. Stops 40 return the racks when the slides are returned. In a modification, where the relay is dispensed with, the pivoted projection 36 is withdrawn from driving connection with its rack by a weakening of the holding magnet produced by the current impulse through the photo-electric cell. In order to avoid errors at the critical point between two numerical values in the tens, the transparent areas corresponding to the numeral " 9 " in each group of unit digit areas is transferred to a position in front of the succeeding group and a yoke 41 on the rack 38, Fig. 3, is arranged to bridge contacts 42, 43, corresponding to the " 9 " and " 0 positions, and thereby to energize one or other of two solenoids 44, 45. The solenoids when energized press upon the scale pan 47 to increase or decrease the load on the weighing-scale and thereby ensure the registration of the correct digit. A time relay and switch device 46 prevents the solenoids operating when the yoke 41 merely brushes over the contacts 42, 43. In a further modification, Fig. 6, for transmitting the indications to a remote indicator, the rack is replaced by a slidable rail 48 which bridges contacts 50 and illuminates indicator lamps 51 behind a ground glass indicator plate. Instead of lamps, relays forming part of the remote indicator may be actuated. Instead of the transparent areas on the revolving screen, non-transparent areas may be provided, the photo-electric cell then operating by a reduction of a steadily-flowing current, this reduction affecting the windings of the holding magnet controlling the pivoted projection 36, Fig. 3. The photo-electric cells may be arranged to switch off the drive.