Patent GB-775641-A (GB)
Title: Improvements in or relating to magnetic recording and reproducing assembly
Inventor: CAMRAS MARVIN
IPC: G11B15/18
Filed: 1953-03-24
Abstract: 775,641. Magnetic recording and reproducing apparatus. ARMOUR RESEARCH FOUNDATION OF ILLINOIS INSTITUTE OF TECHNOLOGY. March 24, 1953, No. 8052/53. Class 40(2). When an electrically - conductive strip 101, Fig. 9, on an endless magnetic tape 81 bridges the contacts of a switch 49, Fig. 4, a relay 106, Fig. 3, is energized to cause a threaded part 117 on a lever 116 to engage a threaded part on a shaft 26. This causes a collar 111 to be raised which through a lever system (Fig. 2, not shown), causes a dog to engage a ratchet 141, Fig. 1, thus raising a shaft 140 and the magnetic head 50, Fig. 4, from, e.g. point A2 to B1. The head is raised until a pin 152, Fig. 3, has rotated sufficiently to strike a pin 118 on the lever 116 and thus disengage the threaded part 117 from the shaft 26. The head is then held in its raised position B1 by a spring 149 urged dog 146, Fig. 1. In an embodiment of the invention a control and indicating knob 170, Fig. 13, is fixed on a sleeve 167 freely mounted on a rod 166 secured to the shaft 140. The knob co-operates with a scale to indicate the position of the head on the tape. Rotation of the knob in one direction causes a member 172 to release dogs 160, 161 controlling the movement of the magnetic head from engagement with the ratchet 141, thus allowing the head to be moved manually. If it is desired that the apparatus shall play or record all the channels and then the whole apparatus be de-energized, a member 180, Fig. 12, opens a switch 173 when the last channel has been played. If it is desired to re-play the channels continuously a master switch is closed and current is still supplied to the apparatus when the member 180 opens the switch 173. In the upper position of the head, the sleeve 167 lifts an arm 181 which through an arm 184 releases the dogs and allows the head to fall under its own weight. As the head falls, the member 172 engages a projection 185 to reset the arm 181 and re-engage the dogs with the ratchet 141. The head then goes through another recording or reproducing cycle. The magazine, which forms the subject-matter of Specification 775,642, comprises an open-ended container 65, Fig. 4, which fits in an enclosure 34 and has holes to take over the tape guiding rollers, the tape driving capstan 30 and the magnetic head 50. The tape is led off the inside of the coil over the switch 49, head 50, along a guide 73 around the capstan 30, along guides 74, 89 to the outside of the coil. A mechanism is provided (see Figs. 7 and 8, not shown), to ensure that the tape is properly looped to engage the capstan. When the magazine is placed on the apparatus a pin fixed to the apparatus disengages this mechanism to allow the tape to be drawn around the capstan. A friction roller 52 is moved, by cams, away from the capstan to allow the tape to be inserted between the roller and the capstan (see Fig. 5, not shown), and is then returned to force the tape into contact with the capstan. The guide roller 42, Fig. 4, is also moved inwardly and outwardly by the cam mechanism to facilitate the positioning of the tape. The head may be provided with a H.F. bias, as described in Specification 617,773.