Patent GB-374877-A (GB)
Title: Improvements relating to prepayment mechanism for gas and like meters
IPC: G07F15/02
Filed: 1931-03-14
Abstract: 374,877. Prepayment mechanism for gas &c. meters. PARKINSON & COWAN (GAS METERS), Ltd. and WILLIAMS, T., Fitzalan Street Works, Kennington Road, London. March 14,1931, No. 7933. [Class 27.] In prepayment mechanism for gas, electric and like meters of the kind in which the valve or switch is operated from a scroll cam, the cam moves a valve or switch operating lever across the face of the cam until it is engaged by the end of the groove and moved to close the valve or operate the switch. The cam is actuated by a differential gear which is rotated by prepayment and by the meter respectively. When coins of two different sizes are to be used, the cam is rotated from the coin-actuated mechanism through two differential gears. As shown applied to a gas meter which can be operated by one or other of two sizes of coin, such as a penny and a shilling, the valve x, Fig. 1, is mounted on a spindle y which has a crank arm z connected to a link 2 provided with a pin 4 engaging the spiral groove t, Fig. 4, of a scroll cam s. As gas is consumed, the cam s is rotated to carry the pin 4, the upward movement of which is limited by a guard plate 6, across the face of the cam, the pin, when it is engaged by the closed end of the groove, being carried over the end of the guard plate, against the action of a spring 5, to turn the crank z and close the valve. The cam s rotates with one sun wheel r of a differential gear, the other sun wheel u of which is driven by the meter through a worm v and worm wheel w. The planet carrier q gears with the planet carrier p of another differential gear which is actuated by prepayment. The sun wheels k, n of this differential are driven respectively from wheels b, a, according as a penny or a shilling is inserted, the wheel a driving the wheel n directly through a sleeve m and the wheel b driving the wheel k through a ratchet wheel f and reducing gears i, j. Coin action, thrust and with delivery proportionate to value of coin.-The coin holder c, Fig. 1, has a cam plate 10 which is engaged by a coin inserted through a slot 11 in the price-change plate. The plate 10 is pivoted at 12 and connected by a link 13 to a toothed member d which engages and drives the wheel a, when a shilling is inserted, and the wheel b, when a penny is inserted. A shilling engages the top sloping edge of the plate 10 which it rotates slightly, while a penny engages the front vertical edge and rotates the plate through about 90‹. Fraud, preventing ; coin-slit closing-devices.- When the cam plate 10 is turned on its pivot by inserting a coin, it allows a catch plate 14 to be turned by a spring 16 and engage behind a fixed stop 18 to prevent return movement of the coin holder, once this has been rotated slightly in the forward direction, until the coin is discharged. The coin-holder disc 22, Figs. 1 and 6, is rotated by a pin 23 on a disc 21 rotated by a handle 20. The pin 23 projects through a slot 24 in the disc 22 which is held by a pawl 26 engaging a tooth 25. When the disc 21 is rotated it closes the coin-slit 11 and an edge 27 raises the pawl 25 before the pin 23 drives the disc 22. Indicators.-A pivoted pointer 7, Fig. 1, moves over a scale 8 to indicate the. extent of prepayment. It is operated by an arm engaging the scroll cam.