GB1275025A - Printing mechanism having a single printing element - Google Patents

Abstract

1275025 Selective printing INGCOLIVETTI & C SpA 19 April 1971 [2 Feb 1970] 21188/71 Heading B6F The truncated spherical type head 26 of a typewriter is rotatable selectively on a substantially horixontal axis defined by a shaft 31 and 15 carried by a forked support 32, 33, 34 rotatable selectively about a substantially vertical axis defined by a shaft 37. The shaft 37 is journalled in a U-shaped bail 41 swing- able about a horizontal axis defined by a hollow shaft 44 to cause the printing head 26 to strike a platen (10 Fig. 1). Keyed to shaft 31 is a toothed wheel 71 which is in mesh with a second toothed wheel 72 integral with a hollow shaft 77. Shaft 77 is connected by means of an articulated joint 81 to a shaft 82 rotatable in a sleeve 83 fixed to an extension arm 84 of the bail 41. Shaft 82 is geared via toothed wheels 96, 97 to hollow shaft 44 keyed to a square shaft 23, which thus selects on the type head 26 the row of the character to be printed. A second square shaft (24, Fig. 1) is rotated to select the column of the character to be printed. Variable impression.-Impression is caused by 360 degrees rotation of a square shaft 19 to which is keyed a hollow shaft 109 carrying cams 159 and 163, Figs. 2 and (3). A cam follower roller 162 is carried by an extention 161 of the bail 41, and a cam follower roller 158 is carried by a lever 151 pivoted on the hollow shaft 44. A spring 152 connected between the lever 151 and an extension 84 of the bail 41 ensures contact of the two rollers with their respective cams. When selections has taken place, cam 163 allows bail 41 to pivot under the action of spring 152 thus initiating the impression action. After an initial rotation of between 40 and 90 degrees of the cam 163 its profile declines abruptly so that its follow roller 162 parts from it. The bail 41 is then subjected solely to the action of the spring 152 so that the type head 26 accelerates. The sleeve 83 fixed to the extension arm 84 of the bail 41, then strikes against a lug 156 of the lever 151 causing the lever 151 to turn. There is then no relative movement between the rocking lever 151 and the bail 41 so that the type head 26 moves at a substantially constant speed arrived at after a period of accelaration. The intensity of impression is goverend by the position of lever 151 after it has been moved by the cam 159 and before it is struck by the sleeve 83, i.e. the amount by which the spring 152 is tensioned. This is governed by an extension 149 of the lever 151 coming into engagement with the profile of one of a plurality of selectable cams (147). The overall impression intensity is governed by selecting one of the cams (147) with a lever (168). The individual character intensity is determined by the angular position of the selected cam which is dependent upon the angular position of the character column selection shaft 24. Arrangement of type; aligning for impression.-The characters are arranged on the type-head 26 in sixteen equidistant rows coplanar with the 31 axis; and in six circular lines perpendicular to the axis. The distribution is such that their impression area increases from left line to right line of Fig. 2. More particularly, the symbols of smaller area (. , + - ) are arranged in the first line and those of larger area (M, W, %, ¢) in the sixth line. To a shaft 177 parallel to the platen is fixed a lever 178 having a forked end 179. The ends of the arms of the fork are wedgeshaped and adapted to engage two corresponding wedge-shaped notches (181, Fig. 1) interposed between the types in the same row during the approach of the type-head 26 to the platen, thereby aligning the selected type for impression.