Patent GB-766782-A (GB)
Title: Improvements in machine for recording on magnetic tape
IPC: G11B15/04
Filed: 1954-08-20
Abstract: 766,782. Selective punching machines. REMINGTON RAND, Inc. Aug. 20, 1954 [Aug. 20, 1953], No. 24286/54. Class 31 (2). [Also in Group XVI] In a machine for preparing a magnetic tape 429 with data in code form to be used in an electronic computer means are provided for entering data in a record card punching machine, and the movement of the record support platen 92 controls the movement of the magnetic tape past its recording head. As shown in Figs. 1, 1A, a power-operated typewriter prints on a work-sheet, and corresponding code data in the form of magnetic spots, as shown in Fig. 11, is recorded in a magnetic tape by a recording head in the manner described in Specification 665,179, [Group XIX], the feeding of the tape being coupled for movement in the manner described in Specification 766,781. The recording head 205, Fig. 43, comprises eight coils 630 selectively polarized by a negative current when contacts 158, Fig. 43, are closed by the rocking of permutation bars 111-118, Fig. 1, as the result of the lifting of a code-key 106, actuated by a bell crank 88 associated with the power mechanism of the particular type or other action. Negative current is supplied through contact disc 634 attached to the escapement mechanism. A second disc 641 has contacts displaced from those of disc 634 so that the punching circuits are set up by one key before a circuit to a code bar release magnet 151, Fig. 43, is closed. The coded data in the tape is in '' blockettes" of characters comprising one hundred and twenty letter-spaces, a blank space occurring only at the end of a " blockettee " which is indicated by an underscore mark. Since all the positions of the tape included within a blockette must contain some character the spaces in between tabulation entries is filled with " space " signals under the control of a FILL IN key on the front of the machine. These signals comprise magnetic spots entered in the 7th and 8th positions as shown in Fig. 11. After a line of punching is completed a righthand margin stop closes a switch 313 preparing a circuit so that when a TRIP KEY is energized closing lower contacts of 247, a carriage return movement is effected without erasure of the data on the magnetic tape 429. With this action a magnet 577 energizes to operate a clamp on the tape feed unit and advance the tape one letter space while the carriage is returning. A carriage-return action, coupled with an erasing action on the magnetic tape 429, is caused by operation of an ERASE key; the magnet 577 is not operated in this case and the tape is reversed in its direction of travel past the recording head and positive current applied to the tape to effect erasure. The circuit for this comprises rectifier A, lines 621, 623, resistances 624 and coils 630. During back-spacing electric current is prevented from entering the tape but upon completion an erasing positive current flows. Keyboards.-The keyboard layout is as shown in Fig. 4, the shaded section being the same as that of a standard key-punch keyboard so that the one keyboard may be used as a typewriter keyboard or as a key-punch keyboard. Key-interlocks.-The trip lever 53 causes a splayed end 71 to enter a ball retaining box 73 to prevent a second key from effecting typing &c., but time saved since the operation of the second key can occur during the actuation of the mechanism inaugurated by the operation of the first key. If a key-lever is depressed when the power roller 29 is not rotating, e.g. in the case of a power failure, the end 71 is retained in the ball box 73 so that no other key can be depressed until the power-roller completes the cycle of a cam roller 79 and restores a detent 62. During the action of case-shifting an extension (175, Fig. 10A, not shown) enters the box 73. Line-locking devices.-Each key-lever carries a lock pawl 262, Fig. 16, which may engage the upper edge of a key line lock bar 263 operated by a crank 292, links 291, 288 from a mechanism actuated by the right-hand margin stop. The bar 263 may also be operated when a carriage-return movement is made to effect erasure of part of a line. Normally an electromagnet 304, Fig. 1, is operated to allow operation of the key-lines but if the power supply fails or during a rewinding operation the electromagnet 304 is released to lock the keyboard. Back-spacing.-The mechanism for backspacing is automatically supplemented in its operation to compensate for the extra load imposed by the tape unit. This is effected by an electromagnet which is energized by contacts closed upon the operation of the back-spacing power action. Spacing between perforations.-The escapement mechanism, Figs. 16, 17, comprises a ratchet wheel 229, fixed pawl 234 (not shown) and movable 233 mounted on a rocker 235 operated from a universal bar. A detent wheel 224 and a pawl 223 coact with the escapement to take up back-lash between the parts, stop the carriage accurately in position and lock the carriage against manual movement.