| 摘要 |
944,678. Typewriters. WALTHER BUROMASCHINEN G.m.b.H. Feb. 28, 1962, No. 7893/62. Heading B6F. Platen rotation; line spacing mechanism.-A line spacing mechanism, for a ten-key adding or calculating machine, having a laterally non- shiftable platen 5, is provided with a linkage mechanism to rotate the platen first in a direction contrary to normal paper feeding direction, before an impression is made, and then in the normal paper feeding direction by a selectably adjustable amount of line spaces, there being an arresting element 14, adapted to remain in engagement with an arrester wheel 7, during rotation of the platen in the normal paper feeding direction, so as to prevent the platen from overshooting the selected number of line spaces. The line spacing mechanism comprises a mainshaft 29 rotating in the arrowed direction, whereby a roller 26 of an eccentric 28, mounted fixedly on the shaft, pivots a lever 19 counter clockwise to displace a link 17, whose one end engages a pin 16 on a pivotally mounted lever 11, causing the arresting element 14, a roller, to rotate the platen 5 two tooth divisions contrary to the normal paper feeding direction (in Fig. 3, not shown). Simultaneously two cam discs 37, 38 co-operating with rollers 33, 34 have pivoted a bifurcated lever 30 clockwise permitting a line space lever 43 to be drawn by a spring 44, against a baseplate 4 of the paper carriage, in readiness for forward rotation of the platen. When impression has been made the lever 19 is returned by a spring 21 to its original position in Fig. 1, and the cam discs 37, 38 return the lever 30 to its former position, the retraction of the line space lever 43 causing a finger 46, thereon, to engage the teeth of a ratchet wheel 6 to thereby rotate the platen 5 in the normal paper feeding direction by the same number of line spaces it has been rotated previously, the arresting element 14 being disengaged from the arrester wheel 7. Continued retraction of the line space lever 43, causes an edge 55 (Fig. 3, not shown) to co-operate with a pin 12, upon which the arresting element is mounted, whereupon the lever 11 is returned to its former position and during this movement the arresting element re-engages the teeth of the wheel 7, whilst the finger 46 co-operates with the teeth of the ratchet wheel 6 and both together rotate the platen in the feeding direction by the remaining number of line spaces. |
