GB903973A - Load cell apparatus - Google Patents

Abstract

903,973. Measuring electrically. TOLEDO SCALE CORPORATION. July 26, 1960 [July 28, 1959; July 11, 1960], No. 26023/60. Class 40 (1). A load cell comprises a flat member, one surface of which is unobstructed and forms a mounting surface for strain gauges adapted to sense flexing of the member, the other surface having a plurality of support members fixed to it and, intermediate the support members, a plurality of load transmitting members joined also to load receiving means so that when the flat member is supported by the support members and a load applied to the load receiving means the flat member is flexed. Pressure-sensitive cell. An annular member 60, Fig. 1, is formed with or connected to supporting legs 21 and is connected by a spider 40 to column 31 with a domed top to which the load is applied. Wire strain gauges are secured to the member above the supporting legs and the legs of the spider and so are alternately in tension and compression in response to the load. The column is extended downwardly so that its movements are limited by engagement with the base. Its lower end is cut away to avoid premature engagement with the base when the load is applied off centre. As shown, the base is integral with the legs 21 but in a modification, Fig. 5, (not shown), it may be separate. Preferably the entire structure is cast as one piece or machined from a single piece to limit the effects of mechanical hysteresis. As shown in Fig. 6, the load-receiving column has an extension 80 provided with a flange 81 to limit rebound movements and the sensitive apparatus is sealed by diaphragms 101, 102 welded to the columns and to a cylindrical housing 103 screwed to the base and to the extension 80 and the base itself. Tension-sensitive cell. As in the pressuresensitive arrangement the load-sensitive cell 160, Fig. 8, comprises an annular element supported on a base by one set of legs and coupled by a spider arrangement to a central member in two parts 230, 250 to which the tension is applied. Connection to the strain gauges are made via a printed-circuit board 211 and the connections are led through a glass member 283, Fig. 9. Sealing diaphragms 190, 260 are welded to the central member and to the frame 240 which is formed as a base and enclosing cylinder. The device is anchored in position by means of a cylindrical member 180 welded to the frame 240 and to a cap 170. Reference is made to Specification 903,974 which is concerned with the use of the diaphragms for encapsulating load cells.