Patent GB-998889-A (GB)
Title: Improved mechanism to effect operation of a typewriter
IPC: B41J5/38
Filed: 1963-02-27
Abstract: 998,889. Typewriters. INTERNATIONAL BUSINESS MACHINES CORPORATION. Feb. 27, 1963 [March 15, 1962], No. 7805/63. Heading B6F. Record controlled spherical type-head machines. A typewriter, in which a spherical type-head 1 is traversed across the platen for printing, is set under the control of a perforator tape 76, Fig. 4a, the sensing mechanism of which sets a plurality of permutation slides 123, permitting latches 64, Fig. 6 to position a number of bails 16 which control the position of the typehead in printing position. Sensing apparatus.-The tape 76 is fed by a sprocket wheel 110 which engages a central row of feeding perforations and which is driven by ratchet and pawl drive, the pawl being oscillated by a follower and cam 107, Fig. 3a, on a shaft 92 driven by gearing from a power source 81 and an electromatic clutch 80. On the shaft 92, Fig. 4a, are six cams 95 which allow mechanical feelers 96 to enter code perforations, if present in the tape 76. This allows selected levers 112 to pivot since they are no longer held by pawls 97. The upper ends of the levers 112 engage in the holes 144, Fig. 8a, in reduced and staggered end portions 143 of the six primary sliding code slides 123. Springs 115 tend to move the strips to the left. Combination type-selecting mechanism.-The slides 123 are arranged vertically above one another in between guide plates 120, 121, Fig. 5. For each setting whether upper or lower case there is only one combination of movements for the character chosen to give an alignment of opening 142 which will allow a sensing pin 126 to rise through the six slides, at a moment decided by cams 135 on the drive shaft 85, Figs. 3a and 3b. Above the six slides 123 are six slides 124a which operate a further combination of selector bails and two slides 124b associated with a case-shift action. Each slide 124a has an opening 146 at each character position, these openings are of two sizes which either, permit movement, or not. Those slides which move to the left allow spring arms 155, Fig. 4a, to cause shafts 73 to pivot. See also Fig. 6, where it will be seen arms 72 engage flexible elements 68, allow fingers 72 of the latches 64 to pivot so that, when a slide 60 is shifted to the left by a cam 56 arms 65 of the type-selector bails 16 are selectively operated. The mechanism for operating the pulleys and tapes to selectively position the type-head is described in Specification 873,920. Cash-shift mechanism: case-shift actions.- Normally the type-head is positioned at a mid-point of the lower-case characters which are arranged on one half of the sphere. To effect case-shift the sphere is rotated 180 degrees by the tilting of a lever 9 carrying a pulley 5 over which is trained the tape 2. Lever 9 is moved by a follower 12 acting on an axial cam 14 which has high and low portions corresponding to upper and lower case-shift. The cam is driven through a spring clutch 30 from a motor 18 and drive 19, 20, 21. Operation of the clutch is decided by the two upper combination strips 124b. If, e.g. a character sensed by the tape is upper case the pin 126, Fig. 5, will pass through slot 152 in one of these two strips and a small opening in the other so the latter is held and the former is held by a latch mechanism 184. If a lower case character is now sensed the corresponding pin 126 is raised but now the upper strip is held by both the pin and latch but nothing is holding the lower strip and as it moves to the left a lever 175, Fig. 86, is rocked and operates the spring- clutch 30 to rotate the cam 14 and shift the type-head to lower-case position. Using auxiliary power.-The motor 18 is also connected to a spring clutch 48 normally disengaged by an armature 49 of an electromagnet 52 whose operation permits one-revolution of a type-selector and impression shaft 53. The magnet 52 is operated by a cam 217 on shaft 85. Shaft 53 drives the shaft 55, Fig. 6, causing the cam 56 which shifts the slide 61 to set the bails 16. Just before shaft 55 completes a full revolution contacts are closed to operate a clutch to drive the shaft 85 for another tapefeed step. When a shift of case is required, operation of magnet 52 is delayed until this is done. Specification 873,920 is referred to.