Patent GB-522891-A (GB)
Title: Improvements in and relating to prepayment gas and like meters
IPC: G07F15/06
Filed: 1938-12-03
Abstract: 522,891. Prepayment mechanism for meters. UNITED GAS INDUSTRIES, Ltd., and CHARLES, A. Dec. 3, 1938, No. 35243. [Class 27] In multi-tariff prepayment mechanism for meters wherein the gas valve or equivalent member is closed by the meter mechanism at a rate depending on the setting of a changespeed gear controlled by a basic charge on rental prepayment mechanism having a time-control, the change-speed gear is changed from the high-tariff to the lowtariff ratio by a cam when the bas'.c charge is prepaid and is returned to the hightariff ratio after a time interval determined by the prepayment. In the construction shown in Fig. 1 applied to a multi-coin prepayment mechanism such as described in Specification 392,530 two co-axial quantity wheels 1, 2 are connected through an epicyclic gear 5 ... 9 to a sun wheel 10 of a second epicyclic gear, of which the second sun wheel 11 actuates the gas valve 16 through a Geneva stop mechanism 12, 13. The meter mechanism 21 acts on the second epicyclic gear to close the valve through a spindle 23, two-speed gear 24, 25, 29, worm gear 20 and the planet carrier 19 of the epicyclic gear. Thus the rate of closing of the valve depends on which gear ratio of the two-speed gear is in use, and this is dependent on whether or not a basic or rent charge is prepaid by means of a second prepayment mechanism R which controls the two-speed gear, ensuring a low tariff when the basic charge is paid and a high tariff when it is not. The two-speed gear comprises gears 26, 27 meshing with the gears 24, 25 and carried by a cage 28 pivoted on shaft 23 so that either of the gears 26, 27 can be made to mesh with gear 29. The cage 28 is adjusted to vary the gear ratio by means of a gear 30, quadrant 31, and lever 35 having a stud 37 adapted to engage cam discs 38 on a shaft 45 controlled by the prepayment mechanism R. The latter may comprise, as shown, a multi-coin mechanism similar to that acting on the gas valve, with quantity wheels 1<SP>1</SP>, 2<SP>1</SP>, and epicyclic gear 5' ... 9', so that when a coin is inserted a shaft 46 is rotated and rotates the cams 38 through gears 48, 49, 50, and epicyclic gear 51, 52, 53, the planet carrier 52 being fixed on the shaft 45 of the cams 38 and the sun wheel 51 being fixed to the gear 50. The cams 38 now set the two-speed gear for the low tariff rate. Rotation of the shaft 46 simultaneously winds a spring 47 the casing of which is controlled by an escapement gear 59 and drives the other sun wheel 53 of the epicyclic gear, so that after a predetermined time the cams 38 are brought back to their original position and the two-speed gear is set at the high tariff rate. The cams may comprise two discs A, B, Fig. 8, as described in Specification 458,753, one disc A having a narrow radial slot to receive the stud 37 and being capable of a limited rotary movement relative to the other disc B, the latter being fixed to the shaft 45 and having a slot sloped at one side so that on rotation of the discs in one direction the stud 37 is gradually lifted out of the slot. This construction ensures an accurate gear change since the stud only falls into the slot when the narrow slot of disc A coincides with it. The cam 38 may be arranged, as described in Specification 519,628 to take into account arrears of the basic charge, being formed as an interrupted annulus so that the cam can still rotate while the change-speed gear is in the high tariff position. A sufficiency of coins must then be inserted in the basic charge coin action to rotate the cam back to the change-over position before the low tariff is again in use. Instead of the spring motor 47 a weight motor or an electric motor 73, Fig. 8, may be used as the time control device. The lever 35 may stop the clockwork when the stud 37 drops into the cam slots; thus a switch 78 may be operated by the lever so that the current operating the electric motor is interrupted. The electric motor may be operated by a battery or secondary cell or from any available source. The spindle 45 may carry or drive an indicator arm 60 showing the amount of basic charge prepaid. Specifications 387,678 and 486,498 also are referred to.