Patent GB-504503-A (GB)
Title: Improvements in and relating to sound reproducing apparatus for endless band sound record carriers
IPC: G11B25/06
Filed: 1938-05-16
Abstract: 504,503. Sound-reproducing machines. DANIEL, K. May 16, 1938, No, 14607. Convention date. May 15, 1937.' [Class 40 (ii)] Relates to apparatus for reproducing 'sound from an endless-band record having a number of parallel sound-grooves recorded thereon, and morÚ particularly to means for mounting the reproducing pick-up and positioning it with the stylus in any selected groove. According to the invention, all arm carrying the pick-up is mounted by means of a universal joint, and its lateral movement in one direction is limited by an adjustable stop coupled to a sound-track indicating' device. In the machine shown, the endless film sound-record 6 is fed from the inside of a coil, and after passing over a rubber-covered drum 3 driven by a motor 1, is rewound on the coil on the outside. The coil is mounted on a plate 13 which is driven by the motor through a disconnectible coupling 15, 16. Guide-strips 10, 11 for the film are associated with pressure rollers 4, 5, the arrangement being such that each guidestrip and the associated roller may be disengaged .from and held away from the film when necessary. A fly-wheel 5a is connected to the roller 5. At a point near where the film is fed to the drum 3, a guide path 7 and a film-tensioning device 9 are provided. The pick-up 23 is carried by an arm 36 which is mounted at X, by means of a universal joint, on a pin 25. The weight of the pick-up is compensated by a spring 26 coiled round a sleeve 27 which is movably but "self-lockingly" arranged on the part 25a of the universal joint. The spring coacts with pins 29, 30 on the members 27, 25a respectively, and the arrangement is such that the tension of the spring is adjustable, and it has no effect when the pick-up is raised. A rod 35, attached to the arm 36, carries a roller 34 which is adapted to be engaged by an inclined portion 33 and an end stop 33a on a plate 32. An edge of the plate is formed as a rack engaging a pinion 37 on a shaft 38 having a knob 39 at its upper end by means of which the shaft can be rotated. The shaft 38 can also be raised and lowered axially by rotating a knob 49 on a cam sleeve 50 which acts upon a pin 51 engaging in a groove in the shaft. The rack plate 32 is guided in a support 44 which is so connected to the shaft 38 as to move vertically with it. A toothed disc 40 on the shaft 38 is formed as a pulley over which passes a cord operating a pointer 42 which moves over a scale 43 graduated in accordance with the number of sound-tracks on the record. To set the pick-up for reproduction from a selected sound-groove, the knob 49 is rotated to lift the shaft 38, and with it the plate 32, which by engagement with the roller 34 raises the pick-up. The knob 39 is then rotated to adjust to the predetermined position the stop 33a which sets the pick-up to the position required, as indicated by the pointer 42. When the shaft 38 is in the depressed position, the pick-up being in action, a locking pawl 66 engages the toothed disc 40, so that rotary movement of the shaft 38 is then prevented. A switch 57 in the circuit of the driving motor is held closed by the end of the shaft 38 when the latter is in its lowest position, and is also controlled by a spring-actuated rod 60 which engages an edge of the record. The switch can open only when the shaft 38 has been raised and the end 62 of the rod 60 has entered a recess in the record.