Patent GB-976473-A (GB)
Title: Improved printing apparatus
IPC: B41J7/44
Filed: 1962-06-29
Abstract: 976,473. Typewriters. INTERNATIONAL BUSINESS MACHINES CORPORATION. June 29, 1962 [July 14, 1961], No. 24997/62. Heading B6F. In a typewriter wherein interposers are individually movable to select a character to be printed and to initiate a printing cycle, a latch is provided to hold each interposer in the position to which it is moved, and the latched interposer is released from the latch after initiation of the printing cycle. In one embodiment, the arrangement is applied to a machine as described in Specification 873,920 wherein the type faces are carried on a single head which is rockable and rotatable to present the required type to the platen. Each key lever 12 pivoted at 15 carries a pivoted member 34 held in the position shown by a spring 36 and adapted to engage an upward arm 42 on an interposer 42 when the key is depressed. In its rest position each interposer is caused by a spring 54 to be held with a fixed pivot pin 48 engaging the left-hand end of a slot 52 in the interposer, the arm 42 situated beneath the member 34, and the right-hand end 64 pressing against a leaf-spring 63. Depression of a key causes the end 64 of its interposer to be moved downwardly and to be latched in such position by the spring 63 engaging the upper surface of the interposer. At the same time projection 62 on the interposer engages a ball interlock 58 which prevents simultaneous depression of more than one interposer, and a universal bail 65 is depressed to move a latch 66 away from abutment against a fixed stop 72. The latch is pivoted to a link 70 urged to the left by a spring 78 and pivoted at 103 to an arm 102 pivoted at 106 and having attached thereto a clutch latch 101 through an intermediate rubber layer 104. Release of the latch 66 when a key is depressed causes the link 70 to be moded leftwardly by the spring 78, and the latch 101 to be moved from engagement with a shoulder 85, 86 on a clutch sleeve 84. The sleeve 84 then is driven through a spring clutch and drives a shaft 92 through a belt connection. One of the projections 94, 96 on the shaft 92 engages a shoulder 98 on the interposer 40 to move the latter to the left, thus disengaging its end 64 from the spring latch 63 so that the spring 54 can restore it to the original position. During the movement of the interposer, a combination of projections 99 thereon, unique to each interposer, engage bails 100 to effect the required orientation of the printing head. One of the projections on the shaft 92 also actuates an arm 109 adjustably connected to an arm 108 which moves the latch 101 back to operative position and at the same time restores parts 70, 65 to their original positions. If a second key is depressed after restoration of the first operated interposer but before the printing cycle is completed, the corresponding interposer is depressed and held latched by the spring 63 until it is released during a succeeding cycle, in which case the parts 101, 70, are not restored until the second cycle is completed. A pivoted bail 69 is movable with the operation of an on-off switch for the machine to prevent release of the latch 66 when the switch is in the off position. Key construction.-A tongue 28 on each key lever engages a frame member 29 to prevent twisting of the key. A leaf-spring 24 biases the key upwardly. In a second embodiment applied to the typelever machine described in Specification 814,400, the interposers, which cause cams to be moved into engagement with a power shaft to actuate the type levers, normally abut at one end against a leaf-spring similar to the spring 63 mentioned above and are latched in depressed position by the spring until released after initiation of a printing cycle. Interlocks.-As in the embodiment shown in Fig. 1, when an interposer is depressed a projecting part thereon engages a ball interlock 158, Fig. 3 (not shown) to prevent simultaneous depression of another interposer.