Patent GB-471555-A (GB)
Title: Improvements in or relating to prepayment meters
IPC: G07F15/06
Filed: 1936-03-26
Abstract: 471,555. Prepayment mechanism for meters. ELECTRICAL APPARATUS CO., Ltd., BARBOUR, R. H., and NOBLE, H. F. March 26, 1936, No. 9003. [Class 27] Mechanism for prepaying basic charges.-In a prepayment electricity meter, a time element for collecting a basic charge, a cut-off mechanism for opening the supply switch, mechanical gearing for interconnecting these parts with the units meter and coin mechanism, and optionally price-adjusting devices, are provided on a gear frame which is readily removable from the casing (leaving behind the switch, units meter, and coin mechanism), and replaceable by a corresponding gear frame without a basic-charge mechanism. The construction of gear frame shown is similar to that described in Specification 443,599, but is modified to include a basic-charge collecting mechanism, and is interchangeable with the mechanism of that specification. It comprises spaced frame plates 10, 11 and 12, the rear plate 12 having holes for fixing screws, and the plate 11 a catch 18 for locating it in exact position with a pinion 113 in mesh with the drive from the meter. The basic-charge motor 22 is connected by a gear train with a pinion 33, Figs. 2 and 4, secured to a vertical shaft 34 carrying at its lower end a worm driving a worm-wheel 36 on a transverse shaft 37. A worm 39 at the other end of this shaft transmits the drive to a pinion 40 of a price-adjusting mechanism, the driven shaft 42 of which conveys the drive through a train of gears 61, 70, 71, 72 and 73 to the shaft 74 of a change-speed gear for coarse adjustment of the basic-charge rate. This change-speed gear drives a sun-wheel 85 of a differential gear whose other sun-wheel 87 is oppositely driven by the coin mechanism in the manner described in Specification 443,599, the resultant movement being transmitted from the central shaft of the differential, by way of a gear train 102 and 103, to a sun-wheel of the differential quantity mechanism 104. The other sunwheel of the quantity mechanism is connected by a pinion 105, and an interchangeable pricechange gear, to the meter driven pinion 113. The planet carrier shaft of the quantity mechanism is comiected by a gear train to a spring barrel 121 for assisting the drive, and to the switch tripping mechanism described in Specification 449,970. The latter mechanism permits of the accumulation of a debit charge by the basic charge motor until a limit is reached, when the drive of the motor is taken up by a slipping connection 76, Fig. 2. Price-changing mechanism.-The price-adjusting mechanism in the basic-charge motor drive comprises an adjustable intermittently engaging ratchet-and-pawl mechanism, and is similar to the mechanism interposed in the transmission from the coin mechanism described in Specification 443,599. The change-speed gear for coarse adjustment comprises three pinions 79, 80 and 81 on a sleeve 78 which can be moved axially on the shaft 74 to bring a selected one into mesh with a respective one of three pinions 82, 83 and 84 connected with the sun-wheel 85 of the differential mechanism. A removable and interchangeable gear carrier 120, Fig. 1, enables the drive from the meter to be varied for price-changing purposes. A pivoted brake lever 128, Fig. 1, locks the meter drive to prevent unwinding of the spring drum 121 when the gear carrier 120 is removed. Indicators.-The indicator disc 16 of the basic-charge price-adjusting mechanism is removable and interchangeable for others appropriate to the different settings of the changespeed gear providing the coarse price adjustment. A pointer 136 on the shaft of the spring drum 121 indicates the credit or debit standing to the consumer. An indicator 14 for the cash inserted is provided as shown in Specification 443,599.