Patent GB-947132-A (GB)
Title: Letter space extend mechanism for typewriters
Inventor: MORRIS JOHN CHARLES
IPC: B41J19/58
Filed: 1961-08-08
Abstract: 947,132. Typewriters. SPERRY RAND CORPORATION. Aug. 8, 1961, No. 28663/6l Heading B6F. In a power-operated type-lever machine wherein an escapement mechanism is actuated in response to each printing operation to produce equal spacing movements of the platen carriage, means are provided which, when set, cause the escapement to perform a second spacing movement after the spacing movement associated with the printing of a character, thus producing double spacing between the characters. Power operation of type levers.-A lever 42 which actuates a type-bar by mechanism, as described in U.S.A. Specification 2,862,591, is operated by a power-lever 13 carrying on a pivot 14 an eccentric cam 12 which is engaged with a power roller 11 to operate a type-bar. The set of levers 13 is pivoted on a fixed rod 16 and each is normally prevented from rotating anti-clockwise under the action of a spring 34 by a latch 29, a nose 38 on which engages a seat 39 on the lever, so that the cam 12 does not engage the roller 11. Depression of a type-key 18 lifts, through an intermediate lever 21, a trigger 26 having a shoulder 27 engaging a nose 28 on the latch 29, so that the nose 38 rides off the seat 39, thus allowing the cam 12 to engage the roller 11 and cause actuation of a type-bar. A lower extension 37 of the latch 29 rides in a groove 35, 36 in the cam 12 under the action of a spring 31, the part 36 causing an initial quick clockwise movement of the latch so that an extension 41 holds the trigger in inoperative position until the extension 37 snaps back into the part 36 when the parts 26, 29 resume their initial positions. The rightward ends of the levers 13 have extensions 49 which overlie bendable ears 51 on a ribbon universal bar 48 carried by bail ends 47 pivoting on the rod 16. The ends 47 are connected through adjustable links 56 with an actuator bar 52 which operates the ribbon vibrator. By bending the ears 51 the timing of the throw of the bar 52 may be adjusted, so as to effect precise operation of the extended-spacing mechanism as described below. Escapement and variable-spacing mechanism; actions other than type actions.-Normal letterspacing mechanism includes a pivoted throwarm 81 for each key action as described in U.S.A. Specification 2,862,591, downward movement of the arm causing, through links 86 . . . 88 and a wire 89, the swinging of the dog rocker 91 of an escapement mechanism 80. Letter-spacing with no printing can also be effected by a space-bar connected to the lever 21 of the double-spacing mechanism described below. For double spacing, a key 72 is depressed. The key at its inner end carries a pin 68 which normally engages the lower of two recesses 66, 67 in the upper end of a lever 63. The other end 62 of the lever in this position engages a shoulder on and prevents spring-urged upward movement of a bar 59 connected by a link 75, 77 to a lever 21 associated with a trigger 26 and latch 29, the latch 29 normally holding inoperative a lever 104 similar to a lever 13 and also carrying a cam roller 12. The lever 104 however has no rightward extension 49. When the key 72 is operated, the pin 68 moves into the upper recess 67 of the lever 63 which thus moves anti-clockwise so that the bar 59 can move upwardly into contact with a tappet 57 on the actuator bar 52. If now a type-key is depressed, typing and normal letter-spacing first occur with anti-clockwise movement of the tappet 57 allowing the bar 59 to move upwardly past the tappet. As the tappet returns to normal position it imparts anti-clockwise movement to the bar 59 which movement through the associated parts 75, 77, 21, 26, 29 causes a power actuation of lever 104. A rod 103 connects the lever 104 to a rocker 102 which acts upon the dog rocker 91 of the escapement, so that actuation of the lever causes an additional letter-spacing movement. Since the lever 104 has no extension 49, the ink-ribbon mechanism is not operated during the additional spacing movement. Double-spacing continues until the key 72 is released.