Patent GB-681707-A (GB)
Title: Improvements in and relating to the lubrication of the mechanism of gas meters
IPC: F16N13/04
Filed: 1949-05-24
Abstract: 681,707. Reciprocating pumps. SMITH METERS, Ltd., CHARLES, A., and CHARLES, J. A. May 22, 1950 [May 24, 1949], No. 13860/49. Class 102 (i) [Also in Group XXXIV] A lubricating system for gas meters, in which the amount of lubricant supplied is proportional to the amount of gas measured, comprises a pump 1 of adjustable output, situated outside the meter casing, having a pump chamber 2 connected by passages 3, 4 to spaced valves 6, 7 with leather or fibre faces. which are both adapted to lift in the same direction and thus control an inlet passage 8 and an outlet passage, not shown. Alternatively, the valves 6, 7 may be ball valves and in either case they may be subjected to spring pressure. A plunger 15 projects from the pump and is rigidly connected to a carrier 18 formed with a longitudinal slot 19, laterally extending arms 20 and a spindle on which is a roller 21. A spindle 28, driven by the mechanism of the meter, has keyed to it a flanged sleeve 30 lying within the slot 19; the sleeve has a forwardly extending key or projection of ratchet tooth form that enters a corresponding recess in the bore of a cam 31 which is held by a spring 32 against the end of the sleeve 30. If the direction of rotation of the meter is reversed, the ratchet slips out of engagement with the cam 31. The cam 31 bears against the roller 21 and thus, as it rotates, lifts the plunger 15 and thereby draws lubricant from a reservoir 41 via a filter or screen 40 and the valve 6 into the chamber 2. When the radial edge of the cam 31 passes beneath the roller 21, the plunger 15 is free to make the instroke and is drawn down by coiled springs 34, thus ejecting the lubricant through the valve 7. The detachable reservoir 41, preferably mounted exteriorly to the meter casing has a base of convex curvature in which foreign matter is deposited away from the intake tube 39. A boring, not shown, is made in the pump 1 from the outer stage of a recess 37 so that the pump may be primed or the reservoir filled, by means of a gun. The outlet of the pump is connected to a multiplefeed system, not shown. for transmitting lubricant via tubes to various parts of the meter, e.g. valves, flag wire bearings, crank spindle bearings and the like. These lubricant tubes are each fitted at their outlets with an adjustable, non- return pressure equalising valve of the spring- and-ball type, which prevents the leakage of gas into the pump. The spindle 28 is driven from the crank spindle of the meter by a system of worm wheels, worms and a flexible drive or other means. The stroke of the plunger 15 may be limited and adjusted by means of a pin which contacts a flange at the bottom of the carrier 18, or by employing cams 31 of differing eccentricities. Alternatively. the plunger may be adjusted in position in relation to the pump chamber so that the effective capacity of the latter is varied. A modified form of the invention is described in which the pump plunger is pivotally connected to a transversely disposed rocking lever maintained in contact with the cam by springs. Means are provided for varying the stroke of the plunger by altering the position of the fulcrum of the lever. In the form shown, the cam 31 may have one or more projections upon its periphery and so the number of operations per cycle of the pump may be varied. As a further modification, the plunger may be moved positively in both directions by the cam.