Patent GB-514996-A (GB)
Title: Improvements in or relating to mechanism for operating metering and printing devices
IPC: H04M15/10
Filed: 1938-05-09
Abstract: 514,996. Automatic exchange systems. ALBISWERK ZURICH AKT.-GES. May 9, 1938, Nos. 13853 and 13854. Convention dates, May 7, 1937 and Sept. 20, 1937. [Class 40 (iv] [Also in Group XIX] Mechanism for operating metering and printing devices especially for registering or recording telephone charges, comprises parts adapted to be stepped forward in different ways under the control of a series of grouped electrical impulses, one part being actuated in dependence upon the total number of individual impulses whilst another part is actuated in dependence upon the number of impulses in the first group. The number of impulses in a group will vary according to the distance of the call, the group being repeated (say) every three minutes in the case of trunk calls or the like. In addition to a charge corresponding to the total number of individual impulses, a supplementary charge, varying only according to the distance of the call, is added on a separate metering device. A wheel 2, Fig. 1, stepped forward by an impulse relay in known manner, rotates through 3, 4 the main charge wheel 6, and also through a coupling 5, 9 and a wheel 11 the supplementary charge wheel 14. The impulse relay also serves to close a switch 24, Fig. 3, to energize a sluggish relay 25 which opens a switch 26<SP>1</SP>. A cam 13, Fig. 2, is rotated with the wheel 11 and, in the case of a shortdistance call, an arm 18 moves on to the step 19 at the end of the first group thereby closing contacts 15, 16, so that when the sluggish relay 25 releases the switch 26<SP>1</SP>, the relay 21 is energized to uncouple the supplement mechanism by means of a lever 23. In the case of a call of a longer distance, the arm 18 moves on to the surface 20 and by closing contacts 15, 16, 17, immediately energizes the uncoupling relay 21, thereby preventing more than a predetermined maximum charge from being added on the wheel 14. In a modification, the addition of more than the maximum charge may be prevented by omitting teeth from the wheel 11. Moreover, the supplement mechanism may be driven by a separate wheel 2 which is moved laterally out of engagement with the common driving means by the lever 13. In a further modification utilizing a separate driving wheel for the supplement mechanism,. a pawl actuated by the impulse relay for stepping both wheels forward is arranged to be moved laterally out of engagement with the supplement wheel. Again, two of such pawls may be used, the one driving the supplement wheel being moved away or uncoupled from the other by the relay 21. A mechanical device replaces the sluggish relay in Figs. 19 and 20. The wheel 2 driven in common with the supplement wheel 27 by the impulse relay rotates the main charge wheel 6, whilst the wheel 27 drives a notched disc 56 engaged by a pawl 60 pivoted on an arm 57 driving the supplement wheel 14. In operation, a pin 81, Fig. 20, on the arm 57 engages a small lever 73 pivoted on an arm 69 which pushes a pin 68 on a flywheel 63 which is thereby set in rotation against the action of a spiral spring 64, the inertia of the flywheel being such that it will not be returned before the completion of one group of impulses. A pin 76 on the flywheel releases a spring-urged arm 78 which moves out of the path of the end 83 of the pawl 60. On the return of the flywheel, the arm 78 is forced back by the pin 76 rocking and releasing the pawl 60 from the disc 56 and hence disengaging the supplement mechanism. Again, teeth may be omitted from the driving wheel to prevent the pawl 60 moving beyond the range of the arm 78. The mechanism may be zeroized by known means (e.g. heart-shaped cams). In a modification of this mechanical embodiment, the wheel 27 is omitted and the disc 56 is fixed to the wheel 4. In a further embodiment, pawls 105, 105a, Fig. 27, are actuated by the impulse relay to operate the supplement mechanism. The first impulse causes these pawls to step forward ratchet wheels 2, 4, the latter, by means of an arm 95 and pawl 97, stepping forward the supplementary numeral wheel 14. A second.impulse rotates the ratchet 2 only, since a cam 94 fixed on a common sleeve 91 engages a pin 111 and disables the pawl 105a. A cam 93, also on the common sleeve 91, closes contacts 114 to shortcircuit a relay 109 energized at the commencement of the call to withhold stops for the.pawls 105, 105a. Its de-energization is rendered sluggish, however, so that if a third impulse is received (e.g. in the case of a trunk call) the ratchet 2 is again stepped forward and the cam 94 releases the pawl 105a, allowing it to give a second' step to the ratchet 4 and the wheel 14. On replacing the receiver, a relay (not shown) is de-energized and a spring, moves sleeves 91, 92 laterally to release the ratchets from stops 101, 102 and allow zeroization by a spring 99.