430,757. Prepayment mechanism for meters. FERRANTI, Ltd., and PRINCE, J., Hollinwood, Lancashire. Dec. 21, 1933, No. 36033. [Class 27] Coin - action, mechanical-connection with delivery proportionate to value of coin; coin - discharging mechanism; fraud, preventing.-In meterprepayment mechanism having a rotary coin receiving member which sets forward quantity mechanism by an amount determined by the value of a coin inserted, and in which a transmission member is first moved axially to select a transmission appropriate to the coin before rotating to effect the setting, the axial and rotational movements of the said transmission member are performed by rotation only of an external knob. As shown, a coin inserted through a slot 27 in the casing is received by a slotted shaft 1 on which is axially slidable against the action of a spring 37 a toothed-wheel 4 fast with a pair of cams 5, 6. The wheel 4 is engageable with toothed wheels 28, 29, 30, and singletoothed locking wheels 31, 32, 33, 34 secured to a shaft 25 ; normally it engages the wheel 34 which locks it against rotation. The cams 5, 6 have a different number of swell portions on their peripheries, and, together with an axial projection 7 on the wheel 4, are selectively engageable with a thrust bar 15 which sets forward the quantity mechanism through ratchet and pawl mechanism. The operating knob 14 rotates independently of the shaft 1, and carries a diametrically slotted cylindrical member 13 in driving engagement with rollers 10, 11 on a U-shaped member 8, axially slidable in the slot in the shaft 1, and having a further roller 9 engaging a fixed cylindrical controlling cam 12. During initial rotation of the knob, the roller 9 engages an axially directed part of the cam 12 so that the member 8 travels axially, and through the inserted coin displaces the wheel 4 and transmission members 5, 6, and 7 by an amount determined by the size of the coin. Subsequently, the roller 9 reaches a circumferentially directed part of the cam 12, so that the shaft 1 rotates, and the bar 15 receives a number of displacements appropriate to the coin : simultaneously a cam 16 on the shaft 1 sets the commodity switch or valve through a thrust bar 17. Alternatively, the cams 5 and 6 may be constructed with single swell portions of different size, or may be replaced by simple radial projections. As the rotation of the knob is completed, the member 8 is withdrawn from engagement with the coin which drops into a receiver, the wheel 4 being returned to normal position by the spring 37 when released by the locking wheels 31-34. In order to prevent the shaft 1 being rotated more than one revolution for a single coin owing to the wheel 4 not being returned to its normal position, an axially sliding plate 50, Fig. 16, bearing against the wheel 4 under the action of a spring 51, is provided, a radial projection on the shaft 1 locking against an abutment 53 on the plate under such circumstances. Ratchet and pawl mechanism 19, 19<a> ensures a full stroke of the operating handle. Specification 285,937, [Class 27], is referred to. Testing coins ; clearing-apparatus, non-automatic.-If a coin of incorrect diameter is inserted, the wheel 4 engages one of the singletoothed wheels 31-34 locking it against all but slight rotation. The coin is discharged by reverse rotation of the knob, the initial part of the rack 19<a> being cut away to permit this, and displacement of a coin supporting plate 20 by an arm 22, Fig. 8, carried by a shaft 23 rotated from outside the casing. Coin-slit closing device.-The shaft 25 has an axial slot normally in register with the slot 27 but which it closes when rotated by the knob 14.