Patent GB-422722-A (GB)
Abstract: 422,722. Postal franking -machines. GRASEBY, R. C., Venner Works, Kingston By-Pass Road, New Malden, Surrey, and WALTERS, E. H., 2, White Court, Platt's Lane, Hampstead, London. Sept. 26, 1933, No. 26472. [Class 100 (ii)] Tripping - arrangements.-In a postal franking - machine of the kind adapted to be set for various amounts and provided with counting-mechanism for registering the amounts set up, a removable counting-mechanism is provided, and locking-mechanisms for the main machine and the counting mechanism are adapted to become effective automatically when the counting-mechanism is removed. The counting-mechanism is enclosed in a casing 30 from which project gear wheels 31 adapted to engage with corresponding wheels 32 in the main machine, and a rack 51 adapted to pass through an aperture in the main machine casing and engage a gear wheel 48 on a rock-shaft 47. The rock-shaft carries a cam 49 which, when the shaft is rocked by bringing the counting-mechanism and main machine together, engages a projection 50 on a lever 42 to cause a hook on the lower end of the lever to release one of a pair of levers 38. The levers 38 support a bar 39 which extends beneath a number of spring- pressed locking-pawls engaging the teeth of the gear wheels 32. In normal use, the pawls permit the wheels 32 to be adjusted, but on removal of the casing 30, the lever 38 is locked by the lever 42 under the control of the cam 49, and holds the pawls in position to prevent adjustment of the wheels 32. The lever 42 is also connected by a link 45 to a rocker 46 which lies under a pusher 20 connected by a bell-crank lever 19 to a trip-lever 18 adapted to be rocked by a letter inserted into the machine. Rocking of the trip-lever when the counter is connected to the machine causes the pusher to rock a lever 22 and release a stop 24 secured to a spring-pressed pawl 14 forming part of a clutch for setting the machine in motion. When the counter is disconnected, the rocker 46 moves the pusher 20 into such a position that it cannot engage the lever 22. The gear wheel 48 also engages a rack 65 running in guides in the main casing. and projected into the counting- mechanism when the parts are brought together. The rack then engages a gear wheel 67 on a rock-shaft 68 carrying a cam 69 acting on a lever 62 which is provided with a nose adapted to engage under a lever 70 carrying a bar 61 underlying pawls engaging the gear wheels 31. When the machine and counter are in position, the cam 69 rocks the lever 62 and releases the lever 70 to permit adjustment of the wheels 31, but removal of the counter causes the pawls to be locked. To prevent fraud, the cams 49, 69 have very small critical positions, so that if not operated sufficiently far the levers 38, 70 are not released, while if operated slightly too far they are locked by shoulders 52, 72 respectively. To prevent removal of the counter from the machine after the operation has started, a segmental cam 75 on the shaft 47 co-operates with a spring-pressed lever 76, the other arm of which is normally supported by the stop 24. When the operation has commenced, the stop 24 permits the lever 76 to rock and enter a notch in the cam 76 and so prevent rotation of the shaft 47.