GB485815A - Improvements in and relating to prepayment meters - Google Patents

Abstract

485,815. Prepayment mechanism for meters. BRITISH THOMSON-HOUSTON CO., Ltd. June 7, 1937, No. 15737. Convention date, June 6, 1936. [Class 27j Mechanism for collecting basic charges ; indicators.-A prepayment meter is provided with an additional differential gear between the coin and quantity mechanisms, which gear registers, and subsequently secures payment for, arrears of basic charge which accumulate after prepayment is exhausted. As shown, a sun-wheel 1 of the quantity mechanism is driven jointly by the commodity meter and a constant speed motor, whilst the planet shaft 2a carries a switch tripping element 3 and a pointer 4 showing the credit standing to the consumer. The coin operated sun-wheel 7 is connected through gears 8 and 9 to a sunwheel 10 of an additional differential gear whose other sun-wheel 14 is connected with the coin mechanism, and whose planet shaft 11a carries a pointer 12 indicating arrears of basic charge. Locking devices 16 and 17 prevent accidental rotation of the sun-wheels 7 and 10. When prepayment is exhausted, the pointer 4 engages a fixed stop 6 at its zero position, and the shaft 2a is arrested after having tripped the supply switch. The continued drive of the constant speed motor is then transmitted from the sun-wheel 1 through planet pinion 2 revolving on its own axis, sunwheel 7, gears 8 and 9, and sun-wheel 10 to the planet shaft 11a, the pointer 12 moving away from its zero position as arrears of basic charge accumulate. When further prepayment is made, the rotation of the sun-wheel 14 is first transmitted by the planet pinion 11 to the shaft 11a, the sun-wheel 10 being held by stop 17 so that no drive is transmitted to the quantity mechanism. When arrears of basic charge have been paid, the pointer 12 engages a stop 15 at its zero position and shaft 11a is secured against continued rotation. Further operation of sun-wheel 14 is then transmitted through the planet-pinion 11 revolving on its own axis, sun-wheel 10, and gears 9 and 8 to the sun-wheel 7 of the quantity mechanism whose shaft 2a is rotated to allow a further supply of electricity. In the modified arrangements of Figs. 2 and 3 (not shown), the two differential gears are arranged coaxially. The arrears indicator 12 is in the form of a graduated disc rotatable behind an aperture in a fixed plate, over a scale on the front of which the credit pointer 4 works, being coaxial with the arrears disc.