594,019. Prepayment mechanism for gas meters. SMITH METERS, Ltd., and CHARLES, A. April 19, 1945, No. 9849. [Class 27] Complete closure of the supply valve when credit is exhausted is prevented by a spring, e.g., by engagement of a spring plunger 24 on the actuating arm 5 of the valve with mounting plate 3, and the continued action of the meter mechanism is taken by a lost-motion coupling and spring in the drive from the quantity mechanism. A restricted supply sufficient for maintaining pilot lights, e.g., in water heaters, is -thus allowed after. credit is exhausted and the full supply cut off. As shown, the lost-motion coupling is between the quantity differential and the driving-member 11 of a Geneva stop mechanism by which it is connected to the actuating cam 20 for the valve arm 5. Pins 13 on the shaft 10 of the differential engage in circumferential slots in the boss 12 of the driving member 11, and a helical spring 15 maintains the pins at the rearward end of the slots in relation to the direction of rotation under consumption. When credit is exhausted, a slot 22 in cam 20 pivots arm 5 to close the valve, but full closing is prevented by engagement of the spring plunger 24 with the fixed plate 3. Consumption then continues at a reduced rate with the pins 13 working round the slots in the boss 12, against the action of spring 15 and with the quantity differential running into debit. This continues until the pins 13 reach the opposite ends of the slots, when a positive drive is established and the valve is fully closed against the action of the spring plunger 24. When further payment is made, a full supply is not available until the pins 13 have been testored to the rearward ends of the slots as the quantity differential is brought to zero credit. Payment is thus secured for the restricted supply. The spring plunger 24 is adjustably mounted on the valve arm 5 so that the extent of the reduced valve opening can be adjusted. Alternative constructions are referred to in which the lostmotion coupling is associated with the valve cam 20 instead of member 11, or, alternatively, in which the pin 21, by which the cam 20 actuates the valve arm 5, is mounted in a slideway transverse to the valve arm and under the action of a spring. Specifications 387,678, 392,530 and 441,270 are referred to.