GB485795A - Improvements relating to gas meters, electricity meters and the like - Google Patents

Abstract

485,795. Prepayment mechanism for meters. ROBINSON & CO. (LIVERPOOL), Ltd., J. H., and FOX, T. March 13, 1937, No. 7404. [Class 27] In a prepayment gas meter of the kind in which the tariff can be altered after a predetermined prepayment has taken place and wherein two sets of gears operatively engageable alternatively are interposed between a meter driven shaft and the quantity mechanism, the alternative gear sets are moved into and maintained in their respective engaged and disengaged positions by positively acting means which is positively driven by the coin-released manually-operated driving mechanism of the meter. After the insertion of a coin, a handle 11, Fig. 4, is turned to rotate a ratchet wheel 12 and an internally threaded sleeve 13 engaging a screw 15 and having a collar 14 for opening the valve. The screw 15 is rotated by the meter to return the sleeve 13 and close the valve, the screw having a worm wheel 26 engaging a worm 25 driven by worm gearing from a shaft 22, Fig. 2. A shaft 16 driven by the meter has fixed to it a wheel 17 which drives a gear 21 fixed to the shaft 22 either through an idler gear 18 or, when the tariff is to be reduced, through reduction gear 19, 20. The change-over to the reduced tariff is effected positively by a cam wheel 27 having peripheral teeth 29 engaged and driven by a pin 32 projecting from an arm 33 fixed to the boss of the ratchet wheel 12, so that, at each prepayment, the cam wheel 27 is moved through one tooth. The wheel 27 has a scroll cam 28 engaged by a pin 35 on the lower end of a two-armed lever 36, on the upper end of which the gear 20 is journalled. The gear 18 is mounted on a plate 39 pivoted on the same axis as the lever 36 and connected to the lever by a pin-and-slot connection. The plate 39 has a pointed projection 42 which engages the side of a movable block 43 pivoted on the pin 35 and guided by an angular slot 45 in the block engaging a fixed pin 44. The block 43 maintains the gear 18 in mesh with the gear 21 until the pin 35 reaches the outer portion of the scroll cam whereupon the gears are changed over sharply. The cam has a displaceable cam wall portion 47 which allows the pin 35 to pass so that the cam can then be rotated without further action on the lever 36.