Patent GB-673238-A (GB)
Title: Improvements in or relating to printing mechanisms
IPC: G06K15/04
Filed: 1950-03-20
Abstract: 673,238. Typewriters &c. REMINGTON RAND, Inc. March 20, 1950 [March 30, 1949], No. 6927/50. Class 100 (iv). A power-operated printing-mechanism having type elements 97 slidable in a carrier 96 selectively movable to position a type element 97 for a printing operation comprises a type-engaging hammer 31 actuated by a bell-crank lever 23 connected to a latch 47 positioned to engage a constantly rotating power-drive 13 which also effects restoration of the bell-crank 23 and hammer 31 by engagement with a portion 61 thereof. As shown the type 97, mounted on a series of vertically reciprocating rods 96, are selectively moved into alignment with the platen 98 for actuation by the hammers 31 via a series of interposers 35 slidable in guides 36, 42 on a transverse bar 43 fixed to side frames 12. The hammers 31 are pivoted at 32 and guided by spacers 33, and have pendent arms 28 connected by links 27 to the bell-cranks 23 pivoted at 21 on transverse bar 17. The latches 47 are connected at 46 to the bell-cranks 23 and slidably move in comb guides 55, 54 secured to cross bars 56, 57 having mounted between them spring plungers 60 tending to move the latches into engagement with the power-drive 13, but the latches 47 are held away by their projections 53 engaging trip levers 101 pivoted at 102. Levers 101 are rocked anti-clockwise by trip bars 107 actuated by the usual related cam mechanisms associated with the type bars moved into printing position, before a longitudinal tooth 14 of the power roller 13 is rotated into the position shown on Fig. 3. The released latches 47 are then engaged by the tooth 14 and the hammers are swung anticlockwise with an accelerating motion. The power of the motion is determined by the length of time the latches are engaged by the tooth 14 so that by movement of the cam portion 62 of cam levers 66 towards or away from the surfaces 52 of the latches 47 the time of disconnection of the latches 47 from the power-drive 13 is adjusted and the power to each hammer is thereby predetermined. Movement to the cam portion 62 is effected in two ways which are complementary (a) a movement common to all cam levers 66 such as is required to alter the power to all hammers e.g. if a large or a small number of carbon copies are to be taken and (b) individual adjustment for each character so that e.g. the hammer to effect the printing of the letter " i " receives less power than one required to print a letter " m." The common adjusting movement (a) of cam levers 66 is effected by an eccentric mounting 65 on a shaft 63 which is extended through the side frame to a knurled knob rotatable within fixed limits and controlled by a six-position detent- and-ratchet arrangement so that the hammers 31 are released from the power source at any of the six positions 1, 2, 3, &c. shown dotted on Fig. 3. Individual adjusting movement (b) of the cam surfaces 62 is controlled by rotation of levers 66 about shaft 63 controlled by sensing bars 68 which move to the left an amount determined by notches I, II or III, Fig. 10, in bars 95 attached to the type rods 96. The leftward movement of the sensing bars is permitted-at a time after the rods 96 have been set but before the tooth 14 is operative-by a bail 86, Fig. 2, mounted on levers 88 pivoted at 91 and carrying followers 92 engaging cams 93 one at each side of the machine. The resultant positions of the hammers 31 at which they are disconnected from the power-drive 13 due to the movements (a) and (b) of the cam surface 62 is shown in Fig. 3. The power mechanism positively returns all the hammers by means of a longitudinal lobe 15 on the power-drive 13 engaging cam surfaces 61 of the .bell-cranks 23 and which are shaped so that the return movement of the hammers is retarded to lessen the impact with which they strike a cross rod 37. Rod 37, rod 26 (which supports the bell-cranks 23), and rod 106, against which the trip levers 101 rest, are all provided with a rubber covering 26 to absorb shock and minimize noise.