Patent GB-486498-A (GB)
Title: Improvements relating to prepayment meters
IPC: G07F15/08
Filed: 1936-12-01
Abstract: 486,498. Prepayment mechanism for meters. UNITED GAS INDUSTRIES, Ltd., SMITH, E. W., CHRISTIAN, A. J., and CHARLES, A. Dec. 1, 1936, Nos. 32976/36 and 11406/37. [Class 27] Price-changing mechanism.-In a prepayment meter adapted to charge for the commodity supplied on a sequence of tariffs brought into operation automatically, a changespeed gear between the meter and quantity mechanisms for effecting the changes in tariff is controlled by a series of adjustable cams or like elements driven by the meter mechanism and rendered operative in sequence. The meter mechanism may operate either on a quantity or a time basis, the adjustment of the cams determining the quantity of commodity supplied or the period of supply under each tariff. As shown, a meter driven shaft l<2> carries three pinions meshing with three wheels i, mounted in a frame h rotatable about the shaft l<2> and alternatively engageable with a broad pinion l<1> connected with the quantity mechanism. Three alternative gear ratios, corresponding to three tariffs, are thus provided in the drive between the meter and quantity mechanisms, change of the ratio being. effected by rotating the frame h. For this purpose, a pinion h<1> fast with the frame h meshes with a pivoted toothed quadrant g<6> loaded by a spring g' and having a pawl g3 coacting with a pair of slotted discs d, e connected through a friction drive a<6>, and worm gearing a<2> and m<1> with the meter driven shaft l<2>. Initially the pawl g<3> bears against the front face of the disc e, and the uppermost wheel i corresponding to the initial high tariff engages the pinion l<1> of the quantity mechanism. As commodity is consumed the meter rotates the discs d and e, and after a predetermined consumption at the high tariff the pawl g<3> escapes through the slot in the disc e and passes into engagement with the disc d. The frame h is consequently turned to bring the second wheel i, corresponding to an intermediate and lower tariff, into mesh with the pinion l<1>. After a predetermined consumption at the intermediate tariff the disc d similarly releases the quadrant g<6> to bring the third wheel i, corresponding to the final and lowest tariff, into mesh with the pinion l<1>. The quantity of commodity supplied at the initial and intermediate tariffs can be varied by adjusting the initial positions of the discs d and e. For this purpose the discs are carried by concentric sleeves d<4>, e<4> on shaft a, the sleeves having secured to their forward ends setting discs d<3>, e<3> with circular series of holes engaged by a pin a<8> on an arm a secured to the shaft a. To effect the adjustment, the shaft a is drawn out by means of a knob a' to disengage the pin a<8> from the setting discs d<3>, e<3> which are then turned to the required quantities as shown by graduations on the discs against a pointer on the arm a<7>. The shaft a is then thrust back to re-engage the pin a<8> with the discs and finally rotated until the end a<9> of the arm a<7> abuts against a fixed stop o determining the initial position of the discs d and e. The quadrant g<6> is also turned back to its initial position with the pawl g<3> bearing on the disc e. A pointer g indicates on a scale b<2> the tariff in force at any moment. In place of the discs d<3> and e3, the discs d and e may themselves have circular series of holes engageable with a locking pin on a third disc secured to shaft a, and be movable along shaft a to disengage the pin when making adjustment. In a further modification, the discs d3 and e3 are replaced by toothed wheels locked in relation to the shaft a by a pivoted pawl from which they can be released when making adjustment. Specifications 387,678, 392,530, and 400,636 are referred to.