GB1165822A - Improvements in or relating to Keyboards for Power-Operated Typewriters and the like - Google Patents

Abstract

1,165,822. Typewriters, &c. SIEMENS A.G. 24 Aug., 1967 [25 Aug., 1966], No. 39011/67. Heading B6F. In a power-operated typewriter or like machine, wherein depression of a key 1 causes movement of an associated selector rod 4 into engagement with a drive means 11 which, when operated, pushes the rod 4 rightwardly so that code teeth 14 thereon actuate selected rockers 13 to produce binary signals, a pawl 7 is provided which locks a rod 4 in depressed position, and movement of the pawl 7 to locking position operates a rocker 10 to trip the drive means 11. As shown, the key 1 is depressed against the action of a return spring 2 connected to an intermediate member 3 which, through projections 21, 22, moves its rod 4 downwardly about a pivot 19. During such movement, the tip 6 of a pawl 7, normally engaging a projection 20 on the rod 4, slides on to an edge 8 on the rod 4 to hold the rod in depressed position with a lug 12 on the rod adjacent to a three-armed drive shaft 11. Movement of the pawl 7 under the action of a spring 9 operates a rocker 10 which through a clutch, causes the shaft 11 to rotate through 120 degrees so as to push the rod 4 rightwardly to actuate the selected rockers 13. Over-centre springs 23 complete the movement of the rockers 13 to set position. As the rod 4 moves rightwardly, a part 15 thereon engages a lug 16 on the pawl 7 to pivot the pawl so that the tip 6 is moved out of engagement with the edge 8 allowing the rod 4 to rise under the action of a spring 18 to its normal position where the tip 6 engages projection 20. Fixed to the shaft of each rocker 13 is a lever 24, Fig. 2, carrying a permanent magnet 30 which operates a sealed-tube magnetic contact 31 to provide the signal. The lower end of each lever 24 carries a pin 25 which, when the corresponding rocker 13 is set, moves into the path of a shoulder 26 on a rod 27. The rod 27 is operated from a cam 28 on the drive shaft to move all the displaced rockers 13 back to their original positions. Repeat action, preventing.-If the key 1 has remained depressed, the projection 21 on the rod 4 will be out of alignment with the projection 22 on the intermediate member 3 when the rod 4 makes its return movement so that the rod 4 can rise and a repeat operation is prevented. A ball-lock 5 prevents more than one selector rod 4 being moved into depressed position at the same time.