Patent GB-508555-A (GB)
Title: Improvements in or relating to sound recording and reproducing apparatus
IPC: G11B25/06
Filed: 1937-12-31
Abstract: 508,555. Tape machine for sound recording and reproducing. DANIEL, K. Dec. 31, 1937, No. 36285. Convention date, Jan. 2. [Class 40 (ii)] [Also in Group XX] Relates to sound recording and reproducing apparatus in which an endless band record has a plurality of parallel longitudinal sound tracks, and the passage from one track to another is effected by a transverse displacement controlled electrically by a contact on the record band. According to the invention, there is provided a switch in the circuit of the driving motor in parallel with a contact automatically temporarily opened after a transverse movement and adapted to be opened or closed by hand as desired. The endless band record 3 provided with several longitudinal sound tracks, mechanically cut or optical, moves over rollers 22, 41, 22a, 18 against the last of which it is pressed by a roller 19. The roller 18 is driven by an electric motor 15 through gearing 16, 17. A reproducer 35 is disposed over the roller 22a, and a recorder 34 over the roller 22. The roller 41 is a shavings remover. A brake 42 smoothes the motion of the record band before it reaches the recorder. The recorder 34 is carried by a slide 20 and balanced by a weight 39. The slide 20 is fitted with a rack 57 engaging a pinion 56 on a spindle 62 influenced by a coiled spring 32. The spindle 62 carries a toothed wheel 51 engaged by a pawl 52 on a freewheel 53 geared to a pinion on the spindle of a wheel 13 geared to a synchronous motor 38. A pin 24 on the wheel 13 co-operates With the armature 6 of an electromagnet 5 and with a cam 59 allowing the wheel 13 to rotate one revolution at a time to feed the recorder 34 from one record track to the next. A spring 76 acts on the rack 57 to prevent back lash, and if strong enough renders the coiled spring 32 unnecessary. A pointer 63 carried by a wire driven by a pulley on the spindle 62 moves along a scale 61 to indicate the position of the recorder. The reproducer 35 is carried by rollers 36, 37 on a guide rod 38 and is balanced by a weight 40. The reproducer may be moved by means of a rack 66 and pinion 65 on a spindle 64 to any desired track of the record indicated on the scale 61 by a pointer 69 driven by the spindle 64. A wheel 67 having teeth corresponding to the sound tracks co-operates with a pawl 68 to facilitate this adjustment. Both recorder and reproducer are lifted and lowered off and on by means of rods 73, 74 and levers 71, 72 bearing on cams 70, 70a geared to the spindle 75 of a combination of switches for determining the operation of the machine, so that the recorder or reproducer is only lowered during recording or reproducing respectively. The operation of the machine is determined by the position of a switch spindle 75 in conjunction with a contact 1 controlled by a notch 2 at the edge of the record 3, and a number of subsidiary contacts or switches. The spindle 75 carries a cam 31 and can be set in either of four positions indicated by A, S, H, St. In the position St (stop), the cam 31 on the spindle 75 opens switch 29 and closes switch 59 and leaves switches 28, 48 closed, the mains 43, 44 then supply current to the driving motor 15 through switch 28, and'a closed contact 30, and the record is driven until the notch 2 in its edge closes contact 1. Then a rectifier 45 followed by a byepass condenser 46 supplies current through contact 1 to electromagnet 5 which attracts its armature 6 to release the pin 24 of the wheel 13 to allow the recorder to be fed one step. This movement of the armature also closes a contact 49 to supply current to the synchronous motor 38 and a contact 7 in series with a closed contact 8 to maintain the circuit of the electromagnet closed independently of contact 1. When the wheel 13 has nearly completed its rotation, the pin 24 deflects the cam 59<1>, Fig. 2, and thereby opens contacts 8 and 30 and closes contact 58. Opening of contact 8 de-energizes electromagnet 5, which allows armature 6 to move again into path of pin 24 and to open contacts 7, 49. Opening of contact 30 breaks circuit of driving motor 15, causing record to stop, and closing of contact 58 energizes an electromagnet 47, which deflects - its armature 60 to lock the synchronous motor 38. The spindle 75 may now be turned to any of the other three positions as desired, whereupon switch 59 opens and electromagnet 47 is de-energized, armature 60 unlocks synchronous motor 38, and wheel 13 turns a little more until pin 24 again abuts armature 6. If the spindle 75 is turned to the position A (off), the main switch 28 is opened. If the spindle 75 is turned to the position S (recording), the main switch 28 is closed to operate the driving motor 15 and start the recording operation, and switch 29 in parallel with the contact 30 is closed to prevent the stopping of the motor when one record track has been made and the recorder has been shifted to the next track, the tracks are then successively recorded. If the spindle 75 is turned to the position H (reproducing), the switches 28, 29 are similarly closed to ensure successive reproduction from the successive tracks, and in addition switch 48, which is in series with contact 1, is opened to put the feed device of the recorder out of action.