Patent GB-455553-A (GB)
Title: Improvements in sound recording and reproducing devices
IPC: G11B3/46
Filed: 1935-03-18
Abstract: 455,553. Sound recording and reproducing machines. KOSMOGRAPHDIKTIERMASCHINENFABRIK GES., 24, Schandauer Strasse, and RYSICK, A., 194, Kipsdorfer Strasse, both in Dresden, Germany. March 18, 1935, No. 8359. [Class 40 (ii)] [See also Group XXXIX] Relates to sound recording and reproducing machines, particularly for dictation, of the kind having a " head " provided with two styli, for recording and reproducing respectively, and in which by the operation of a hand lever the head is raised and lowered and adjusted to bring either stylus into operation, whilst at the same time the feed mechanism is engaged or disengaged, as necessary. According to the invention, the machine, which employs a turntable for disc records, is provided with means for setting the recording and reproducing head by rotary adjustment on its carrier. The apparatus shown comprises a casing 1 having a hinged lid 2 which can be supported by a stay 4 in the raised position shown in Fig. 2, but which normally lies horizontally. A turntable 7, located in an opening in the lid 2, and mounted by means of a boss 10 on a spindle 9, is driven by a motor 6 through friction wheels 106, 107, the latter engaging a flange 8 on the turntable. Means are provided, as described in Specification 455,599 for holding a record disc on the turntable, and for ensuring a positive driving engagement. The recording and reproducing head 26 is provided with two styli 27, 28, Figs. 7 and 8, mounted in a common holder 29 having a stem which is inserted into the usual needle socket. The head is rotatable about an horizontal axis, so that it can be set with either the recording-stylus 27 or the reproducing-needle 28 in the operative position. For this purpose, the head 26 is mounted on an arm 41, pivoted at 39 in a sleeve 32 which is rotatable in the tubular end of a carrier arm 20. A pin 38 on the sleeve 32 engages in a cam groove 48 in a slide 47 that is reciprocable so as to cause the head 26 to be rotated in either direction from the neutral position shown in Fig. 7, the head being at the same time lowered to bring either stylus 27, 28, as required, into contact with the record disc. When recording, a pin 45 engages in the forked end 50 of the slide 47, to prevent lateral oscillation of the recording-head. Movement of the slide 47 is effected by means of a hand-lever 52, Fig. 2, to which the slide is linked. The lever 52, which is rotatable about a shaft 51 in the carrier arm 20, also controls a half-nut which is adapted to couple an extension 21 of the carrier-arm to a feed-screw 25, geared to the turntable spindle 9. In addition, the lever 52 actuates a change-over switch 55, by means of which the head 26 may be connected through an amplifier either to a microphone or to a sound-reproducing circuit. Thus, when the device 26 is put in position for recording by operating the lever 52, the feed-mechanism for the arm 20 is made operative and at the same time, connection is made between the head 26 and the output side of an amplifier, to the input side of which terminals for a microphone are at the same time connected through a transformer. When the lever 52 is moved so as to position the head 26 for reproducing, the feed-nut is disengaged and the device 26 (then serving as a pick-up) is connected to the input side of the amplifier, the output side of which is simultaneously connected to terminals for a loud-speaker or headphones. The switch may also be adapted for switching the motor on and off. Fig. 4 shows the circuit arrangements. Five switch levers 55a ... 55e are coupled to the hand lever 52 for simultaneous operation, the associated contacts being connected as shown to terminals for a microphone 61, input terminals 114, 1141 of an amplifier which is external to the instrument, output terminals 115, 115<1> of the amplifier, and terminals 127, 128 for the recording and reproducing head and the loud-speaker &c. respectively. A transformer 109 is connected between the microphone and the terminals 114, 114<1>, and rheostats 69, 65 are provided for controlling the input currents. A voltmeter 116 is connected across the output terminals. The extension 21 of the carrier arm 20 passes through a slot 22 in a panel 3 formed as part of the lid 2, a scale being provided adjacent to the slot to indicate the position of the stylus on the disc. A lubricating funnel (not shown), mounted on the lid 2, is branched off to all parts which require oiling. In a modification, Fig. 14 (not shown), the invention is applied to a machine having an acoustic sound-box which is rotatably mounted on a pivoted lever, the latter being adapted to be rocked by a cam associated with a hand lever which rotates the sound-box and also controls the feed-mechanism. The machine may comprise several turntables operating either simultaneously or in succession. Specification 443,431 is referred to.