| 摘要 |
1309447 Typewriters &c RUTISHAUSER AG Gebr 24 April 1970 [25 April 1969] 19872/70 Heading B6F Line spacing, Fig. 7.-The drive mechanism includes a motor 10, a slipping clutch 8, a pair of opposed ratchet wheels 12, 13, and a pulse emitter 28 in the form of a perforated disc 29, a light source 30 and a photodiode 31. The pawls 18 and 19 for the ratchet wheels are operated by an electromagnet 20. Electric switches 23, 24, situated in the motor circuit, are associated with each pawl. Line feed movement is initiated either by a key or by an electronic computer or a programmer. In addition, control could be effected by a magnetic tape or punched tape. Energization of electromagnet 20 causes switches 23, 24 to be closed, the pawls to release the ratchets 12, 13 and the motor 10 to drive shaft 11, which in turn drives feed rollers (5, Fig. 1) or pin bonds (7, Fig. 2). At the same time, pulse emitter 28 transmits current pulses to the computer or programmer. After a predetermined number of pulses, the electromagnet is deenergized, but the switches 23 and 24 only open when their respective pawls 18 and 19 drop into their locking positions. By having the ratchets opposed, forward and reverse motion is pre. vented. With a ledger sheet feed (Fig. 1), a magnetic stripe or band is provided on the edge of the ledger sheet, and a magnetic marking corresponding to the last entry line, e.g. the number of lines of entry so far been made, is recorded on the magnetic stripe or band to be detected at a later insertion. |
