| 摘要 |
1,162,330. Weighing apparatus. MEPAG A.G. April 23, 1968 [Oct. 4, 1967] No. 19171/68. Heading G1W. [Also in Division G4] A precision or analytical balance comprises a pivotally mounted balance beam 2 which carries on one end a weighing pan 3 and on the other end a scale 47 bearing in coded form digits corresponding to the inclination of the beam, a light projection apparatus 48-50 for projecting the scale 47, a photo-electric device 55, 56 arranged for actuation by the projected scale image and arranged to operate a printing apparatus 37-42 for printing out weight values, and a manually-operable mechanical-optical micrometer 26-34 for obtaining accurate weight values. With a load to be weighed on the pan 3, indexing weights 7 are suitably removed from carrier members 6 extending from a pan support 4 until the balance is roughly in equilibrium, the weights 7 being moved by a cam and lever arrangement 8, 9 which is actuated through gearing 11 by a manually rotatable knob 12, the gearing 11 being also arranged to operate an indicating drum 13 which provides a coarse weight indication of the load in a window 14 of a housing 5 of the balance when the balance beam is roughly in equilibrium. A more accurate weight reading is obtained at a ground glass window 23 at which a graduated scale 17 on the beam 2 is projected by a projecting apparatus 18-20, this scale 17 being mounted adjacent to the coded scale 47 which is simultaneously projected on to a screen 51 and which provides a coded image at the screen 51 corresponding to the readings obtained at the window 23. The optical micrometer 26-34 provides further accuracy in the weight readings and comprises a rotatable mirror 27 arranged in the light paths 21, 52 from the scales 17, 47 and mounted so as to be rotated through a cam and gear arrangement 28, 29 by a manual control 30, the further accuracy being obtained by rotating the mirror until one of the graduations coincides with a forked indicator mark 34 on the window 23, the amount of such rotation being indicated at a further window 33 by an indicating drum 32 operated by the manual control 30. The accurate weight of the load is then obtained by reading the digits appearing in the windows 14, 23 and 33 and a printed record of such reading is obtained on a band 37 by arranging that the indicating drums 13, 32 are operatively connected to type rollers 38, 41 and that the coded image on the screen 51 corresponding to the indication in window 23 is scanned by photo-cells 55, 56 which provide pulses to actuate through electromechanical apparatus 62, 63, 64 two further type rollers 39, 40, a striker bar 42 being arranged to urge the band 37 into engagement with the type rollers 38-41 and being controlled electrically by a unit 67 which for scanning of the coded image by the photo-cells 55, 56 tilts a mirror 57 in the path of the rays from the coded scale 47.
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