Patent GB-850575-A (GB)
Title: Balance, in particular laboratory or chemical balance
IPC: G01G1/28
Filed: 1959-04-10
Abstract: 850,575. Weighing apparatus. METTLER, E., [trading as METTLER, FABRIC FœR ANALIPENWAAGEN, E.]. April 10, 1959 [Nov. 29, 1958], No. 12230/59. Class 143 Weighing apparatus particularly intended for laboratory use comprises a pivoted beam, at least one set of annular weights fitted with depending legs and arranged coaxially about a vertical axis, a weight carrier suspensible from the beam and liftable therefrom by a vertically movable arresting member, and an apertured horizontal disc rotatably mounted below the weights of a set, the arrangement being such that when the weight carrier is suspended from the beam it carries only these weights whose'legs pass through the apertures in the disc. One set of four weights is shown, each weight having on its underside. three recesses and, equally spaced between the recesses, three legs-the recesses being numbered 22 to 25 and the legs 45 to 48 for the respective weights 18 to 21. Attached to the weight carrier 10 are three radial spoke-like supports 15 to 17 (17 not shown) arranged so that they engage the recesses in the weights to prevent rotation and having notches 22 to 25 to keep the weight coaxial. The apertured disc 42, through a central hole 44 of which the weight carrier 10 may move vertically, is shown supporting weight 18 so that only weights 19, 20 and 21 are carried by the weight carrier: these weights thus load the beam 6 on the side remote from the fixed counterweight 8. The selection of which weights are supported by the disc and which by the supports of the weight carrier is made by rotation of the disc. To change the loading the arresting member must first be raised. This member comprises the plate 39 attached to the vertically movable member 30 which is actuated by rotation of cam 36. Pins 40 and 41 on plate 39 are arranged so that raising the arresting member lifts the beam from its pivot and weight carrier 10 from knife edge 9. A lug 54 is also raised with the arresting member and retracts pin 55 from one of a series of holes 53 in the periphery of disc 42. All the weights are then supported by the weight carrier and the disc may be rotated to select a different combination of weights. The apertures 49 (not shown), 50, 51 and 52 in disc 42 and the values of weights 18 to 21 are preferred to be arranged so that rotation of the disc through 120 degrees will pass it through successive positions (each locatable by pin 55 in a corresponding hole 53) applying from zero weight to the sum of the whole set in equal increments. In Fig. 2 (not shown) is depicted a suitable arrangement of apertures for the case in which the relative values of the weights in order from the centre outwards is 1:1:2:5. The apparatus may be provided with operating knobs to rotate both cam 36 by means of shaft 37 and also disc 42 e.g. by means of gearing engagable with a toothed rim on the disc. A scale graduated in weight units may indicate the disc's position. The weight carrier may also support further sets of weights below the set shown and has at its lower end (not shown) a hook for a scale pan.