Patent GB-781769-A (GB)
Title: Improvements in or relating to magnetic recording or reproducing apparatus
Inventor: DOUGLAS ERIC CHARLES
IPC: G11B25/06
Filed: 1954-08-05
Abstract: 781,769. Magnetic recording and reproducing apparatus. ELECTRIC & MUSICAL INDUSTRIES, Ltd. Aug. 4, 1955 [Aug. 5, 1954], No. 22712/54. Class 40 (2). A magnetic record apparatus has spools arranged substantially diagonally across a rectangular panel, and has controls positioned at two raised opposite corners of said panel. The magnetic tape passes from one spool to the other along a slot 7, Fig. 1, formed by the inner edge of one of the raised corners and a member 8 which is raised higher than the said corner to facilitate insertion of the tape. A supply spool (not shown) and a take-up spool 37 are carried on freely rotatable fluked shafts 22, 23, respectively, having flanged discs 27 by means of which one or other may be driven, through the medium of a movable intermediate pulley 44, by a disc 42 on a shaft driven by motor 40. A fourposition control 10 sets the apparatus for Fast Forward, Rewind and Record or Replay by means of cam-discs 192, 195, 114 and 197, Figs. 3 and 4, mounted on a control shaft 115. In the Monitor (neutral) position, a four-armed lever 82, Fig. 6, controlled by cam-disc 114, holds the intermediate pulley 44 out of contact with either of the discs 27. Movement of the control 10 to the Fast Forward position or to the Record or Replay position causes the lever 82 to be moved to the position shown in Fig. 7, whereby the intermediate pulley 44 is moved to drive the disc 27 carrying the take-up spool 37, brake pads 55, 66 are removed from discs 27, brake pad 74 is removed from pulley 42, and light pressure is applied by a pad 98 to the disc 27 carrying the supply spool. Movement of the control 10 to the Rewind position, Fig. 8, establishes a driving connection to the disc 27 carrying the supply spool and releases all brake pads with the exception of a light pressure applied by pad 107 to the disc 27 carrying the take-up spool 37. When a recording is to be made on a new tape a counter 16, driven by a belt from shaft 23, is set to zero reading by means of a knob 17, and a knob 14 controlling the recording/reproducing amplifier is switched on. The operation of press-button 11 then closes the contacts 255, 256 of a lamp housed in the press button, which is translucent, closes contacts of a switch 266 of an erase and bias oscillator, and an ear 253 rocks a bar 257 which withdraws a pin 262 from a recess 192<SP>1</SP> in camdisc 192 mounted on control-shaft 115, so that the control 10 can be rotated to the Record/ Reproduce position. A stud 194 on plate 192 is thus moved away from the inner ends of spring- loaded levers 214, 219 whereby the end 220 of the latter rides over an ear 253 on the bracket 252 carrying the press-button 11 to retain it in the operative position, and the end 215 of lever 214 enters a slot 234 in a bracket 229 carrying Reproduce press-button 12 to prevent its operation while the Record press-button 11 is in its operative position. At the same time, the rotation of cam-plate 195 causes a surface 196 thereon to engage the roller 167 on a lever 154 pivoted at 155 and move the said lever 154 so that a spring-loaded pad 161 presses the tape against an abutment 177 and a turned-up end 164 engages a projection 153 on a lever carrying a pressure roller 151 which thereby presses the tape against a capstan shaft 140 of a motor 118. The rotation of control 10 also causes a member 200 on the cam disc 197 to actuate the arm 206 of a switch 43 to complete circuits to drive motor 39 at relatively low counter-clockwise torque sufficient to wind tape on to spool 37. The recording level is controlled by knob 14 operated in conjunction with a volume indicator 19. Restoring control 10 to the Monitor position terminates recording and stops the machine. During Rewind and Fast Forward operations the levers 214, 219 both engage the slots 234, 254, respectively, in the brackets carrying the press-buttons 11 and 12 to prevent their operation, and the rotation of cam-disc 195 effects no movement of lever 154, pad 161 or pressureroller 151. During the Rewind operation, a member 199 on cam-disc 197 actuates the arm 207 of switch 43 to drive motor 39 at high speed in reverse direction, and during the Fast Forward operation a member 198 on cam-disc 197 actuates arm 205 of switch 43 to drive motor 39 at full speed in forward direction. To initiate a reproducing operation press-button 12 is operated and internally illuminated, similarly to the press-button 11, and becomes locked in the operative position by lever 214 while button 11 is locked in its inoperative position by lever 219. At the same time a slant surface 232 on the bracket supporting knob 11 engages a pin 247 on a bar 243 and moves said bar into the path of the end 156 of lever 154. Thus, when control 10 is moved to the Record/Reproduce position while the reproduce button 12 is in its operative position the lever 154, moved by the surface 196 of cam-disc 195, moves bar 243 endwise to complete connections to the amplifier for a reproducing condition. Specifications 693,685 and 693,695 are referred to.