Patent GB-739809-A (GB)
Title: Improvements in or relating to the recording and reproduction of sound and other signals
IPC: G11B5/004
Filed: 1952-07-03
Abstract: 739,809. Magnetic recording and reproducing apparatus. FRIES, G., and INGLESBY, J. C. VREDENBURG-. July 2, 1953 [July 3, 1952], No. 16754/52. Class 40 (2). A method of making and reproducing a magnetic or other kind of record on tape comprises taking the tape from one spool to another in such a manner as to form on part of its path a closed cylinder, the inside or outside of which is scanned by the transducer. In the simplest embodiment, Fig. 6, the tape 2 is fed slowly through rings 4, 5, and a transducer 8 is made to encircle the outside of the cylinder so formed, the transducer 8 being carried on a ring 10 which is rotated by gearing from a motor 9. Alternatively, the transducer may be made to scan the inside of the cylinder by means of gearing driven by a motor 12. Recordings so made can be arranged to have intermittent spacings y, Fig. 2, so that the record can be cut up into sheets for subsequent reproduction on a cylindrical mandrel. In another embodiment, Fig. 7, a cylinder of tape may be formed transversely of its width, and held stationary by plates 19, 22 and rings 20, 21 while the transducer 18 is rotated and traversed by means of a lead screw. At the completion of each recording the tape is moved by a given amount so that sheet records may be produced as shown in Fig. 3. In a further embodiment, Fig. 8, the spools 26, 30 are arranged inside the cylinder, and the transducer 31 is made to scan the outside surface. Figs. 14 and 24 show mechanism by which the transducer 61 and erase head 62 is made to scan the cylinder, and the method by which a fresh length of tape is moved into position on the cylinder when the heads 61, 62 reach the end of each traverse. The apparatus is driven by a motor 59 whereby a lead screw 59 draws a carriage 60 along a rod 82 by means of a split screw nut 164, Fig. 18, carried by tonglike legs 163. When the carriage 60 reaches the end of its traverse it presses a switch button 170, Fig. 20, to close a solenoid circuit to operate a plunger 174 carrying a wedge 175 which forces the legs 163 apart to release the carriage 60 which is immediately withdrawn to its initial position under the influence of a coil spring 168, Fig. 14. During this operation the legs 163 are held apart by a wedge 1771, Fig. 21, and the circuit.of the solenoid is maintained by contacts 107 which have been closed by the movement of a bellcrank 105 coupled to the plunger 174. The arm 104 of the bellcrarik 105 also intercepts a nose 102 on an internally toothed ring, which engages a sprocket wheel 90, slips on the core member 84 and causes the takeup shaft 49 to be rotated within the cylinder 35 and a fresh length of tape to be drawn to the outer surface thereof. When the carriage 60 reaches the initial position again, the wedge 177 is pushed out from between the legs 163 by the rod 176, and a pair of contacts 109 are broken to release the solenoid plunger 174 so that the arm 104 is withdrawn from the nose 102 and a fresh traverse of the carriage 60 is commenced. A modification of this embodiment is shown in Fig. 16, in which the transducer carries out rapid vertical upward scans under the control of a quick-thread lead screw 59, the return motion being effected by gravity. In this embodiment, the cylinder is held stationary and the tape slowly and continuously fed to the outside surface of the cylinder by means of the gearing 131, 133 and 134. The invention is not restricted to magnetic recording and a needle or light beam may be employed. In the latter case sound-modulated X-rays or electron rays may be used. When using X-rays duplicate records are obtained by placing tapes on top of each other during recording.