Patent GB-529164-A (GB)
Title: Improvements relating to constant mesh variable speed gear
IPC: G07F15/08
Filed: 1939-03-29
Abstract: 529,164. Price-changing mechanism for meters. UNITED GAS INDUSTRIES, Ltd., CHARLES, A., and CHRISTIAN, A. J. March 29, 1939, No. 9810. [Class 27] [Also in Group XXIV] Mechanism for preparing basic charges. Pricechanging mechanism. A constant-mesh epicyclic change-speed gear, for prepayment mechanism of gas, electricity and like meters, such as that described in Specification 392,530, comprises input and output elements and an axially adjustable element that is alternatively retained against rotary movement or locked to one of the remaining elements without interruption of meshing or drive and is adjusted in position automatically by a control element actuated by the prepayment mechanism. In one form, Fig. 1, the input element is a sun wheel 8 driven from the metering mechanism through a spindle 5 and gears 6, 7; and the output element is a planet carrier 1 on a spindle 2 coupled to the worm spindle 3 of the differential quantity mechanism of the prepayment apparatus. The axially adjustable element is a sun wheel 9 meshing with the planet wheel 10 and adapted to be locked by pins 14, 15 either to a fixed plate 13 or to the planet carrier 1. The spindle 2 may carry a pointer showing at any time the amount of the basic charge standing to the credit of the consumer, and a wheel 12 integral with the wheel 9 may drive through toothed and worm gearing 40, 39, 37, a drum 35 for recording arrears of the basic charge when the sun wheel 9 is locked to the planet carrier 1. Axial movement of the wheel 9 is effected by a collar 28 secured on the hub of the wheel and engaged by a resilient fork 27 actuated from a double cam 18, 19, Fig. 2 such as described in Specification 458,753. The fork 27 is supported by a bell-crank lever 29, Fig. 3, pivoted at a fixed point 30 in the mid position of travel of an arm 26 carried by the cam-actuated lever 22, which has a pin 21 co-operating with the periphery of the cam 19 and with a notch 23 in the cam. The cam 19 has a pin-and-slot connection with the cam 18, which is fixed on the planet-carrier spindle 20 of the cam-operating differential gear and serves to lift the pin 21 from the notch 23. A pin 32 on the bell-crank is linked by a spring 33 to a pin 34 on the arm 26. Operation is effected from a basic charge mechanism similar to that described in Specification 522,891 but having the disposition of the planet carrier and first sun wheel reversed in relation to the concentric spindles of the quantity wheels. On the lifting of the pin 21 from the notch 23, the bell-crank 29 throws the wheel 9 of the change-speed gear to the right, locking it to the plate 13 to bring in the high transmission ratio. The spindle 20 is slowly rotated to bring the cams 18, 19 to the initial position, when the stud 21 re-enters the slot 23 and the wheel 9 is thrown into locking engagement with the planet carrier 1, so that the gear rotates as a unit until further prepayment of the basic charge. To enable the drum 35 to return to zero position on prepayment of the basic charge, a bearing 41 for the shaft of the worm 37 is displaceable automatically, by means of a sliding operating member and a bell crank lever, to disengage the worm from the drum; a spring connecting the drum to its spindle then returns the drum to zero position. In a modification, Fig. 6, the sun wheel 47 is driven from the metering spindle 46 and the planet carrier 48 is mounted on a spindle 49 driving through worm or other gearing 50 the planet carrier 57 of the quantity mechanism. A sun wheel 52 mounted loosely on the spindle 49 has a limited axial movement, effected by a fork 55, to engage pins 54 with the planet carrier or to engage the boss of the wheel 52 with an adjacent pawl. The fork may be controlled from a timing device, or from the metering mechanism to be effective after a particular consumption has taken place. In another modification, Fig. 9, the planet carrier 59 is locked against rotation, for one ratio of transmission, by the arm 67 of a lever 65 for effecting axial movement of sun wheel 60, the boss of which is connected by a pin-and-slot coupling 64 to the driven worm 62. Alternatively, the driving sun wheel may be the axially movable element, the driven sun wheel being directly connected to the driven element of the mechanism to which the gear is applied. In further modifications, the planet carrier, together with one of the sun wheels, is axially movable and provided with the coupling means whereby engagement and locking with the second sun wheel are effected ; the operating lever is actuated through a coiled spring ; and the sun wheels may be internally toothed annuli.