GB813875A - Improvements in typewriter reach adjustment and escapement - Google Patents

Abstract

813,875. Typewriters &c. SPERRY RAND CORPORATION. Feb. 26, 1957 [March 12, 1956], No. 6427/57 Class 100(4) A power-operated key-controlled typewriter has a train of parts operating a noiseless action which includes a cam and means operated by it for affording the printing impact before power is applied to operate the escapement mechanism through linkages controlled by the cam. When a key 21 is pressed eccentric roller 56 is rotated into engagement with power roll 54 through train of parts 57. Power arm 58 is lifted and through stud 59 rocks bell crank 60 clockwise against the resistance of spring 61. Cam face 62 depresses roller 64 to rotate cam lever 66 anticlockwise about 67 and pull down link 68, which pivots operating lever bar 53 about 69 to rock lever 47 clockwise about 49. Sublever 33 pulled anti-clockwise about 39 by link 46 pushes arms 26 through a distance limited by reach stop 40, after which they continue to finish the printing stroke by momentum stored in weight 98. Each cam lever 66 is connected by link 73 with an adjusting dog 74 pivoted at 76 and biased against adjusting screw 78 by spring 61. This limits the downward movement of link 68 to prevent overthrow and enable each reach stop to be adjusted to allow a complete printing impact before letter spacing occurs. Bail bracket 79 supports bail 86, which is common to all bell-crank cams 60, and an escapement bracket 82 to which is attached at 84 escapement tie link 83. As cam 60 continues to turn clockwise about 71 bail 86 is pushed to the left to pull on link 83 and operate the escapement mechanism. Face 63 of cam 60 is so shaped that the type operating linkages are not being moved at this time and the reach stop is maintained in face-arresting position. Specifications 688,289 and 712,705 are referred to.