Patent GB-436239-A (GB)
Title: Improvements in and relating to prepayment meters
IPC: G07F15/08
Filed: 1934-05-17
Abstract: 436,239. Prepayment mechanism for meters. CHEETHAM, G. A., Hamewith, Westmorland Road, Urmston, Manchester, GRAY, A. H., Aldersyde, Mossgrove Road, Timperly, Cheshire, ASH, F. S., 20, Malvern Avenue, Flixton, Lancashire, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. May 17, 1934, No. 14961. [Class 27] In prepayment meter mechanism of the kind wherein the quantity of commodity supplied is varied automatically in accordance with the rate of consumption and comprising two trains of gearing between the meter rotor and the commodity side of the prepayment differential mechanism, one of the trains of gears includes two coupling wheels adapted to be coupled together by a unit comprising a wheel, or worm, or pinion, or a pair of any such members geared or connected together, which is moved so that the meshing member is moved in a direction substantially radial to one or both of the coupling wheels by mechanism responsive to the rate of consumption of commodity. As applied to a prepayment electricity meter, the meter rotor R, Fig. 1, drives a shaft 20 carrying two wheels 8, 14. A parallel shaft 21 drives through gears 11, 12, 13 the commodity side D of the prepayment differential (not shown). The wheel 8 drives a wheel 9 loose on the shaft 21, but having a pawl 9<a> in driving engagement with a ratchet wheel 10 fixed to the shaft. This constitutes one train of gearing between the rotor R and the commodity shaft D. A sleeve 19 loose on shaft 21 carries a wheel 15 engaging the wheel 14, and one wheel 16 of a pair of coupling wheels 16, 17, of which the other wheel 17 is fixed to shaft 21. The wheels 16, 17 are normally coupled together by a pinion 18 carried in a rocking frame 25a and held in engagement with the wheels by a counterweight 24<a>. When the rate of current consumption rises above a predetermined value, the armature 29 of an electromagnet EM rotates and, by an arm 30 engaging an arm 26 on the shaft 23 of the frame 25<a>, rocks the frame to move the pinion 18 out of engagement with the wheels 16, 17. The train 14, 15, 16, 17, 18 constitutes the second gear train and it has a bigger velocity-ratio than the train 8, 9, 10. When the pinion 18 couples the wheels 16, 17, the ratchet wheel 10 overruns the pawl 9<a> and the commodity shaft D is driven at a quicker rate than when the train 8-10 transmits the drive from the rotor R. In a modification, Fig. 2, the shaft 21 is driven by the planet cage P<3> of an auxiliary differential P. One sun-wheel P<1> is driven from the wheel 8 on the shaft 20 and the other sun-wheel P<2> is driven in the reverse direction from the wheel 14. In this case the wheels 16, 17 are normally disconnected and the electromagnet EM operates to engage the pinion 18 with the wheels when the current rises above a certain value. A pawl P<5> prevents rotation of the wheel P<2> in the same direction as the wheel P<1> and the frame 25<a> has a pawl 25d to lock the wheel 17 when the pinion 18 is moved out of engagement, the wheel 17 in this modification being loose on the shaft 21. Two further forms are described in which the coupling wheels are not coaxial. They are coupled together by a pair of wheels and by a wheel and worm respectively mounted in a rocking frame which is actuated when the current consumption is above a certain value.