GB1001080A - Improvements in and relating to timing devices - Google Patents

Abstract

1,001,080. Prepayment meters. ALBERICE METERS Ltd. Aug. 21, 1963 [Aug. 27, 1962; April 4, 1963], Nos. 32787/62 and 13382/63. Heading G4V. In its application to a prepayment timecontrolled meter a screw-and-nut quantity mechanism controls a switch, relative axial motion between the spur wheel driving the nut and the spur wheel driving the screw causing operation of the switch and the axial motion being accelerated at the point of switch action. In Fig. 2 spur wheel 18 is mounted on a sleeve 20 rotating in a bearing in mounting-plate 11. Spur wheel 22 is mounted on a spindle 21 threaded into the sleeve 20. The threaded connection between spindle 21 and sleeve 20 has considerable backlash normally biased one way by a spring 24. Holes in the spur wheel 22 hold captive ball bearings 25, 26 which; when the end 23 of spindle 21 is at its furthest point of travel towards microswitch 30, 32; lie in conical recesses in the opposed face of spur wheel 18. When coin action rotates wheel 22 with wheel 18 held fast, the first part of its rotation drives the ball-bearings out of the conical recesses in wheel 18 and thereby displaces wheel 22 to the left as permitted by the backlash. The switch operates to connect the associated apparatus and a timing motor restores the quantity mechanism by rotating wheel 18. As the mechanism approaches normal, the ball bearings snap into the recesses on wheel 18 and provide a fast axial motion of spindle 21 to operate the switch. The ball-bearings are held at different radial positions. In the arrangement of Fig. 3 there is no significant backlash needed between the hollow screw 42 and the nut 41. Spur wheel 50 is mounted on a plain spindle 48 and drives the screw by means of a sliding pin connection which allows relative axial motion. A plate 45, carrying hemispherical projections matched by corresponding recesses in the opposed face of spur wheel 40, is locked for rotation by pins and can be displaced axially with wheel 50. A spring 52 holds the wheel 50 and plate 45 together and against the end of screw 42. When the screw is displaced by the coin mechanism 12 the projections are driven out of their recesses withdrawing the spindle 48 rapidly and holding it until the screw 42 catches up with the plate 45. On restoration the screw leaves the plate 45 behind together with spindle 48 until the projections match their recesses whereupon the spindle snaps forward to operate switch 30, 31.