Patent GB-780393-A (GB)
Abstract: 780,393. Typewriters. UNDERWOOD CORPORATION. Aug. 10, 1955 [Aug. 13, 1954], No. 23027/55. Class 100(4) [Also in Group. XIX] In a combined accounting machine and typewriter, comprising differentially-settable printing bars as well as type actions operably against a common platen, impression hammers for the printing bars are movable in unison from the operative position to a normal position, in which latter position they make way for the type actions. The invention is applied to a machine in which computing mechanism printing bars 18 are disposed immediately to the left of the printing point 19 of a typewriter mechanism 70. In the present machine, the impression hammers 718 for the printing bars are mounted in a laterally movable carriage 719, which is normally positioned to the left and clear of the path of movement of. the left-most type-writing lever 17. The carriage is moved to position the hammers opposite their respective bars 18 only when impressions are to be made. Folio number and date printing bars are disposed to the left of the amount bars and with their groups of hammers also mounted in the carriage. Typewriter mechanism. The typewriter keys 50, Fig. 1, are adapted to lower individual links 43 to engage hooks thereon with a power-driven snatch roll 47, which thrusts the link forwardly to actuate its respective type lever 17 through linkage 37, 38, 32 and 33. Computing mechanism. Differential bars 95, Figs. 1 and 1A are adjusted vertically by the coaction of feelers 112 with a stationary field of stops 108 set column bycolumn under the control of a ten-key keyboard (not shown). Positive and negative racks 211, 212 depending from an arm 210 on each bar 95 are adapted for engagement by a cross-footer 215. A third set of racks 235, connected with the bars, is adapted for selective engagement by four rear registers A, B, C and D. The machine includes function control levers, as 301, Fig. 1A, actuable by tappets on control dogs 296 attachable to a plate 298 of a tabulating paper carriage 10. The mechanism is actuated by cyclic oscillation of a main shaft 250. Carriage tabulation. A tabulation stop lever 350, Fig. 1A, normally lies clear of the carriage dogs 296. During machine operation, a link 368 is first raised and hooks over the lever so that when the link returns during the return half cycle the free end of the lever is raised to intercept the carriage in the next stop position. The stop lever 350, when so raised, rocks a lever 376 counterclockwise and a roller 382, Fig. 1, on the latter raises the carriage rack 72 to release the carriage for movement. A stationary stud 372 finally cams the link 368 clear of the stop lever 350 so that normal control of the carriage by its rack and escapement is resumed. Tabulation cut-out is effected in preselected columnar positions by carriage tappet actuation of a rod 395 which displaces a push rod 397 to rock the link 368 clear of the tabulation stop lever 350 which consequently remains ineffective. Impression hammer carriage. The impression hammers 718 for the printing bars 18 are slidable between upper and lower plates 720. 724 of the carriage 719, the upper plate 720 having lateral arms 721, Fig. 3, guided by rollers 722, 723 and the forward edge of the lower plate 724 resting on a guide roller 725. A spring 727 holds the carriage in its normal leftward position of Fig. 3, with the hammers 718 out of register with their printing bars 18 and clear of the typewriting levers 17. During operations in which an impression is required, a slotted link 755 is engaged with a stud 754 on a lever 750 having a roller 751 bearing against a..cam 748 on the main shaft 250. During cyclic operation, the lever 750 and link 755- are lowered and then raised by the cam 748, whilst an arm 765, rockable on shaft 250 between stops. 766 and 767 on the cam, engages over the roller 751 to delay the return upward movement. The link 755 is connected by means of a bellcrank 756 and spring 757 with an arm 721 of the carriage which is therefore moved rightwardly (Fig. 3), to register the hammers with the printing bars for an impression to be made, and then returned. Accurate registration of the hammers is ensured by engagement of a lip 763 on the carriage with a resilient stop 764 to limit movement, the spring 757 yielding. Control of hammer carriage movement. The slotted link 755, Fig. 7, is only engaged with the stud 754, for the lever 750 to be effective to move the hammer carriage into operative position, upon the rise of one or more of the amount printing bars 18 into a printing position. When this occurs, the corresponding zero print control hooks 804 (see below) are constrained by their bars 18 to travel along a rearward path during their downward cyclic movement. Notches 840 in the hooks then engage and carry downwardly a bail 841, rocking a shaft 843 which, through an arm 845 and link 846, moves the link 755 into operative engagement with the'stud 754. Impression hammer actuation. At the end of the forward clockwise movement of the main shaft 250, a stud 768 on an arm 770 secured thereto engages over a pawl 771 carried by a lever 772. As the shaft 250 and arm 770 return, the lever 772 is rocked and raises the plunger 774 and push rod 778, the latter trippimg a common latch plate 774, normally holding the impression hammers retracted, and releasing the hammers for impression movement by their individual springs 746. This, however, only occurs if the hammer carriage has been moved from its normal position of Fig. 3, to the impression positiom, the latch plate being clear of the push rod 778 in the normal position. A dog 782 engages under a collar 781 on the push rod to hold the latch plate clear until the hammers have been, restored. Restoration of the hammers and release of the dog 782 are effected by a bail 783 actuated by a lever 787. An arm 791 on the shaft 250 carries a dog 792 which, towards the end of the forward stroke, enters into driving engagement with a stud 795 ,on the lever 787. As the shaft 250 returns the lever and bail are rocked to restore the hammers and trip the dog. Selective blocking of impression hammers.. The calculating folio number and date printing bars are arranged in separate groups, each with its own group of im- ,pression hammers 718. 718a and 718b. Figs. 2, 3 and 7. The hammer group 718 is disposed at a higher level than group 718b, and the group 718a at a lower level. Upper and lower blocking slides 830 and 831 are mounted for transverse movement on the hammer carriage by means of slots 833, and normally obstruct forward movement of the folio number and calculating groups of hammers 718a, and 718 respectively. Fingers 834 and 835 on these slides are adapted each to abut the side of the leftmost printing bar of its group raised to a printing position. When the hammer carriage 719 is moved to the right, prior to making an impression, springs constrain the slides to accompany the carriage until arrested by engagement of the fingers 834 and 835 with a raised printing bar of the group. Continued movement of the carriage results in the hammers required for operation passing clear of the blocking slides so that only these hammers are released for operation when the hammer release latch plate 774 is tripped. A blocking element 856, Fig. 1, prevents release of the date and folio number hammers except when tripped by tappets on the control dogs 296 in preselected columnar positions. Control of zero and protective star printing. Insignficant zeros are suppressed by means of hooks 804, Figs. 1 and 7, carried between arms 802 on a cyclically rocked shaft 801. The hooks engage over the ends of zero-set differential bars 95 restoring them to normal position wherein the printing bar positioms a protective star at the printing line. The hooks slide idly over the rear face of digit-set differential bars 95. Moreover, each hook has an ear 812 extending leftwardly behind the adjacent hook so that significant zeros shall be printed. Provision is made for disabling the hook 804 of the second lowest order during total operations, so that zeros are printed in the cents orders when the the total is zero. Protective stars, replacing insignificant zeros, are only printed in preselected tabular positions, the hammers otherwise being blocked by means of the slides 830 (see above). In the preselected positions, a carriage controlled rod 858, Fig. 3, is raised and prevents movement of the slide into blocking relation with certain of the hammers. The rod 858 is insertable into, any one of a series of guide holes 860 according to which orders are to be open to protective star prints. Specification 401,904 [Group XIX] is referred to.