Patent GB-723144-A (GB)
Title: Printing machine
Inventor: HYLAND JOHN JOSEPH
Filed: 1952-05-16
Abstract: 723,144. Record-controlled printing-machines. BURROUGHS ADDING MACHINE CO. May 16, 1952, No. 12488/52. Class 100 (4). A printing-machine comprises a plurality of printing elements 30 having print and non-print positions and being grouped to form different characters by being selectively controlled in various combinations to print one of the characters and with operable members for selective withdrawal of certain elements from the print position, and movable elements to cooperate with the elements remaining in print position to print the character formed thereby. The machine comprises a plurality of individual print sections in the form of narrow rectangular panels arranged vertically in abutting relation and supported between side plates 15 secured by tie rods 17. The front of each panel is formed by a block 19 of mouldable synthetic resin, the top and. bottom edges converging forwardly to terminate in a rectangular end portion 20 freely mounted in a support 21. Each block 19 is secured to recessed heads 24 at the front corners of each panel 18, and the heads 24 also engage upper and lower straps 25 secured to plates 15. Each portion 20 contains two print heads 29 arranged side by side, and each consisting of thirty-five wire printing elements 30 extending through and movable in guide tubes 31 moulded in block 19. The rear projecting end of each tube 30 is fixed in a plate 32. A sheet 33 and carbon strip 34 are arranged between the elements 30 and print hammers 22. Each of the two groups of wires 30 in a panel 18 is supported by a pair of spaced bars 36, the inner edges nf which converge rearwardly and which are joined by spaced plates 37. Rods 41 extending through plates 37 and.slidable in guide plates 42 are fixed to the rear ends of the wires 30, an enlargement 43 being formed at the joint. A spring 44 fitted on each rod between plate 42 and a collar 50 urges the element to its rear or non-print position. The rods 41 are of different lengths and the elements in each group are arranged in three vertical rows, those in the centre row being longest. In Fig. 2 two shorter elements terminate at 39 and two longer elements at 40. The reciprocating movement of the elements is controlled by electromagnetic devices 38 mounted on the inclined surface of one of the bars 36, so that as the elements progressively increase in length and approach the centre line, the devices 38 also progressively approach the centre line to co-operate with their respective rods 41. As shown in Fig. 2, the two left-hand devices 38 are associated with the uppermost and lowermost elements of one outer column, and the two right-hand devices with the uppermost and lowermost elements of the other outer column. The upper left-hand and lower right-hand devices are shown energized, permitting the elements to be moved to the non-print positions, while the other devices are not energized, and the elements retained in printing position. Each device 38 has a spring-controlled armature 47 having a shoulder 49 which engages a collar 50 to latch the element. Movement of the elements is limited by engagement of the enlargement 43 with the restoring bail 53 in its dwell position, which it assumes at the beginning of a print cycle when all devices 38 are de-energized. The bail 53 is advanced, after printing, to restore all retracted elements to their print positions, reciprocation of the bails of the various sections being simultaneously effected by means of bell-cranks 55 actuated by cams, &c., and having arms received in recesses in blocks 54 slidable in the heads 24. A hammer 22 for each head 29 slides in a guide 57 and is aligned by combs 58. A spring 60 engaging an abutment 61 on the hammer urges the latter rearwardly. The hammers are alternately controlled from above and below by the armature latches 65 of magnets 66 engaging between abutments 62, 63 or in a recess 64. When the magnets 66 are deenergized the hammers are held as shown, but when the magnets are energized the armature latches are disengaged and the hammers.impelled rearwardly by spring 60. Immediately after printing the hammers are returned by a bail 67 operated for example by a cam 68 which may be operated by the drive which simultaneously actuates bails 53. Fig. 5 illustrates a printing head with elements in the "1," "5," &c., positions retracted, and remaining elements in the "2," "3," "4," &c., positions arranged to print letter " I." The selective energization of devices 38 may be controlled by means of control cards having columns containing twelve index point positions, the first three points to be sensed, i.e. "12," "11," " 0," being zoning points for letters A-I, J-R, S-Z respectively, and each letter having further assigned thereto one of the numerical index points " 1 "-"9." Figs. 6 and 7 illustrate the circuits controlling the devices 38 of one print head. Each device 38 has one terminal joined to a common bus-bar 69, to 70 and 72, and the other connected to an individual conductor 71. Record cards are fed successively to a sensing device comprising a contact roll 73 and a series of brushes 74, one for each card column. A, distributer 75 operates in synchronism with the card feed so that its wiper successively engages its twelve contacts simultaneously with the sensing of the corresponding index point. All the contacts of the distributer are multipled to the other print heads. Three zoning thyratrons 76, 77, 78, which remain conductive once they are fired until the voltage is removed from the plate elements thereof, are assigned to the index point positions "12," " 11," "0." The plate elements are connected to associated zoning relays 79, 80, 81, and the firing of any one of the tubes by the sensing of a "12," "11," or " 0 " hole simultaneously with the engagement of the distributer wiper with a corresponding contact determines the zone of the alphabetic character to be printed. The fourth zoning relay 82 is assigned to the printing of numerals "1 "-" 9," but if tube 76, 77 or 78 is fired, a relay 83, multipled to the cathode elements of the tubes, is energized and by opening its contact 84 disconnects relay 82 from the power supply 85, but if no zoning tube is fired, relay 82 is energized to close its contacts "1"-" 9," to await the sensing of the numeral index point. With any one of tubes 76-78 rendered conductive the second hole is sensed by brush 74 and through the distributer 75 results in the firing of one of the thyratrons 86-94, and the establishment of circuits through one of the sets of alphabetical contacts. Rectifiers 96 prevent any shunting effect of unrelated circuit groups which may have multiple connections to various conductors 71. By way of example the operation for printing letter' "I," represented by "12" and " 9 holes, is as follows. Brush 74 sensing "12 and "9" index points fires thyratrons 76 and 94. When the control card enters between 73 and 74 the cam C1 closes its contact and remains so throughout the cycle. Initially thyratrons 76-78 and 86-94 are not conductive due to the application of a negative bias from 85 through the bridge network of each tube to the grid, 'and when C1 closes, positive voltage is applied to the plate elements of tubes 76-78 from 85 through 97, C1, 99, 98. With the sensing of a " 12 point and with the distributer wiper at the " 12 " position, zero potential from the intermediate terminal of source 85 is applied through 100, the distributer "12" contact, and 101 to the midpoint of the bridge network connected to the grid of tube 76, and at the same time this potential is connected through 100 to the other midpoint of the network, through 73, 74, 105. The grid voltage of tube 76 is thus raised to zero, causing the tube to fire, whereupon current flows from the positive terminal of source 85 through 97, C1, 98, 79, 76, 83, 100 to the intermediate terminal of 85. Relays 78, 83 are thus energized and held so by cam C1. Energization of relay 83 opens contact 84 to disconnect relay 82 from the positive terminal of 85, preventing contacts "1"-" 9" from closing. Energization of 79 closes contacts " H "-" I." Contacts " J "-" R," " S "- " Z " remain open since tubes 77, 78 are not fired in the absence of "11" and "0" holes. Immediately after the sensing of the zoning points cam C2 is operated to close its contacts, thus preparing a holding circuit for any subsequently fired tube 86-94, the circuit extending from the positive terminal of 85 through 97, C2, 107, to 106, and through a resistance to the plate element of each numeric tube. Cam C2 maintains its contact closed throughout the sensing of the numeric index points and opens the contact directly after bail 53 advances the retracted printing elements. Between the sensing of the zoning and numeric index points cam C3 closes its contact until the printing operation is completed. With the sensing of the " 9 hole, and with the distributer wiper in the " 9 position, zero potential at 85 is connected through 100, wiper of 85, "9" contact of 85, 108, to one midpoint of the bridge network of tube 94, while the other midpoint is connected-to the zero potential through 100, 73, 74, 105, 109, raising the grid voltage to zero and causing the tube to fire. The tube is maintained conductive from the intermediate terminal of 85, through 110, 94 and its holding resistor 106, C2 to the positive terminal of 85. Relay 110 is energized by the current flowing from the plate of tube 94 and is used in connection with the elimination of zeros to the left of a significant figure. On the completion of the sending of the " 9 " point, cam C4 closes to establish circuits, for the energization of devices 38 of the printing elements to be retracted, from the positive terminal of 85, through 97, C4, 70, 69, the particular device 38, 71, 95, the contact "I" of relay 79, 94, relay 110, to the. intermediate terminal of 85. As these circuits are closed a parallel circuit from the "I" contact