Patent GB-1170485-A (GB)
Title: Driving Mechanism
IPC: H04L17/24
Filed: 1967-05-26
Abstract: 1,170,485. Typewriters; selective printers. INTERNATIONAL BUSINESS MACHINES CORP. 26 May, 1967 [29 June, 1966], No. 24534/67. Heading B6F. A typewriter having a spherical type head 10, Fig. 1, or a selective printer having a cylindrical type head (not shown) mounted on a traversable carriage 12 and pivoted for impression of a type character, following rotary, tilting or sliding movement of the type head, is provided with a type selection mechanism 19, 20 for the rotary, tilting or sliding action of the type head, each type selection mechanism, which is actuated in response to a coded signal delivered by a magnetic tape (not shown), including two sets of cams 29 . . . 32 and 51 . . . 54, Fig. 2, mounted slidably on rotary square shafts 27, 24 and displaced axially in a binary coded combination by activated cam followers 38 . . . 38b, to displace the cams 32, 54 a corresponding amount and thereby displace one or the other of character selective output members 45, 56, which co-operate with a pinion 59, to move the links 60 and thereby effect the rotation and/ or tilting or sliding movement of the type head 10 so that the latter presents a selected character opposite the printing position along the platen 11. In operation a coded signal, representative of the type character and derived from the magnetic tape (not shown), is applied to a selected number of electromagnets 90, 101, 102, whose armatures 91 are rocked clockwise to rotate a bail 99 on the one hand and engage a halfrevolution clutch 22 of a motor 21 to begin rotation of shafts 24, 27 and the drivingly associated cam 84 and, on the other hand, to permit springs 94 to rock bellcranks 92 articulated to links 95 which rock latches 73, Fig. 4, of cam follower 38 . . . 38b, and interposers 61, provided with a pair of spring biased bellcrank levers 67, 69. Anticlockwise rocking of latches 73 causes a lug 74 on the respective bellcrank levers 67 to be pivoted into the path of oscillating fingers 75 on a shaft 78 coupled by a link 83, Fig. 2, to a similar shaft 80 and rocked by the cam 84. Downward movement of the finger 75 displaces the interposer 61, which pivots the cam follower 38, formed by an actuating arm 44 and ball retainer 42, anticlockwise, whereby the ball retainer 42 and balls 43 are moved into the path of the face cam 30, the continuous rotation of which causes the balls 43 to engage the lobe 34, 35, 36 and displace the cam 30 axially towards the cam 32. The lobe of cam 30 has a height corresponding to a unit axial displacement the heights of lobes on cams 31, 32 corresponding to two and four units of axial displacement, respectively, whereby selective actuation of interposers 61 and followers 38 . . . 38b, causes a corresponding axial displacement of the cam 32 which varies between one and seven units. Non-actuation corresponds to zero displacement. Displacement of the cams 32, 54 is applied through the output members 45, 56 and a pinion 59 to the links 60 articulated to an arm 108, Fig. 1, which is provided with a tape pulley 111 supporting the tape 112 trained over type head pulley 113 and guided over a further pulley 114. The arm 108, Fig. 3, is provided with a tooth rack 115 which actuates a pinion 116 fast on a pin 117 supporting a further pinion 118. The pinion 118 in conjunction with a tooth rack 121 rocks an arm 120 in the opposite direction to that of the arm 108, the arm 120 supporting a tape pulley 122 over which is trained a tape 123 passed around a type head pulley 124 and a pulley 125. The tape 123 co-acts with the tape 112 to prevent backlash of the type head 10, Following character selection the interposers 61 are restored by fingers 81 on the shaft 80 which engage lugs 82 on the bellcrank levers 69, the latter being restored by pivoting of the latches in the opposite direction through link 95 and bellcranks 92 which are reset by a bail 107 oscillated by a crank 104 connected to gear 105, meshing with a gear 106 fast with the shaft 27. In a modification the pinion 59 and links 60 are replaced by a sliding bar 128 (Fig. 8), articulated to a fulcrum lever 135, which carries the respective tape pulleys 130, 137.