Patent GB-521027-A (GB)
Title: Improvements in letter spacing mechanism for typewriting machines
IPC: B41J19/64
Filed: 1938-11-10
Abstract: 521,027. Typewriters. CARPMAEL, M. H. (Royal Typewriter Co., Inc.). Nov. 10, 1938; No. 32761. [Class 100 (iv)]  Letter-spacing mechanism.-To provide for typing justified lines, the feed-rack is moved longitudinally of the carriage, during letterspacing, by means of a lever which is fulcrummed on the framework and pivotally connected to the carriage and feed-rack at spaced points, adjusting-means, operable in any position of the carriage, being provided for varying the distance between the points to adjust the letter-spacing movement. The mechanism shown in Figs. 1 and 4 comprises a rack 9 which co-operates with the escapement-pinion 23 and is secured to a bail 10 having arms 11, 12 mounted for pivotal and laterial movement on pins 13, 14 secured to the carriage B. The rack is held in engagement with the escapement-pinion by spring-urged yokes 15, 16 which are pivoted on the pins 13, 14 and have cross-pins 20 engaging the arms 11, 12. The rack 9 is pivoted to a slotted link 31 which is guided by a pin 34 on a bracket 30 secured to the carriage. A lever 37, having a slot 40 engaging a pin 38 on a stationary bracket 29, is formed at the front with spaced arms 41, 42, the arm 41 having a slot 43 which engages a pin 44 on the link 31. The arm 42 is connected by a pivot 51 to a plate 45 having pins 47, 48 co-operating with slots 49, 50 in the bracket 30. Teeth 46 on the plate 45 co-operate with a pinion 54 on a shaft 53 which is mounted in the bracket 30 and a bracket 52, and is provided with a knob C. During each letter-spacing movement, the lever 37 is displaced and, unless the pivot 51 coincides with the pin 44, the link 31 advances the carriage relatively to the rack and thereby increases the letter-spacing movement, the increment being determined by the position of the pivot 51 relatively to the pin 44. A drum 55, secured to the shaft, is provided with circumferential scales a ... d for use when typing justified lines of 5, 6, 7, and 4 inches width respectively. A scale-pointer 62 is formed on an arm 60 connected by a pivot 59 to. an arm 56: which is pivoted at 58 to the bracket 52. The arm 56 is formed with a pointer 71 which is set with reference to marks 67 ... 70 formed on a plate 63 and arranged at the same distance apart as the scales a ... d. The knob C and associated parts, and the pointers are locked in adjusted position by engagement of the pivot 59 with one of a series of holes formed in a drum 72 secured to the shaft 53, the arm 56 being sprung laterally to disengage the pivot. In operation, the pointer 61 is moved into register with the scale a ... d corresponding to the required line-length, and the knob C is turned to bring into register with the pointer the scalenumber corresponding to the number of spaces in the line-deficit, this number having been determined by typing a trial line. The line is then re-typed, the spaces 1 being increased in the above-described manner to produce a justified line of the required length. If the zero-graduation of the scales registers with the pointer, the pivot 51 coincides with the pin 44, and normal spacing is effected.