SU49354A1 - Device for recording and reproducing sound on an endless tape - Google Patents

Description

Mechanical engraving of sound on film as a deep and transverse method has long been known. Sound recording on celluloid and gelatin is usually done by cutting the sound groove with a special chisel. Very sharp incisors are required, as only in this case they leave behind a furrow with the smallest roughness that ensures sound reproduction without hissing. Such incisors are very quickly blunt and for this reason various known techniques are commonly used to soften celluloid, and the incisors themselves are made of possibly hard material (a sapphire incisor can produce up to twenty records on a celluloid plate of an ordinary gramophone format).

However, experience has shown that even the sharpest cutters cannot leave behind a completely glossy mark.

Therefore, another well-known method of mechanical recording on a film may be of considerable interest, in that celluloid or gelatin is not cut through, but the extrusion of a sound groove in a film under the pressure of a blunt writing end of a recorder is used. This method may be applied exclusively to the film, due to the fact that it is sufficiently thin. For ordinary gramophone celluloid plates, this method of recording could not be applied, since the plates are much thicker than ordinary film.

When squeezing the sound groove, the film sags, forming an absolutely glossy groove, which gives a completely hiss when playing.

To make such a recording by pressure, it has already been proposed to use a roller, which serves as a substrate for a thin celluloid surface on which recording is made, and made of wood or other fibrous material that allows some kind of extrusion of the celluloid surface during sound recording.

According to the invention, the said roller, which is a transporting drum for an endless tape of film and simultaneously serves as a substrate for recording sound on this tape, is wrapped around its entire cylindrical surface with a rubber band. The use of a rubber band makes it possible to achieve a sound groove of considerable depth by bending the film, (the film is crimped).

The recording facility built on this principle has given exceptional results in recording quality.

and especially for noiseless pauses and, as experience has shown, it reserves in this respect any newest shellac plate.

The proposed device for recording and reproducing sound is illustrated by a schematic drawing showing a rotating transporting drum 1 covered with rubber band 2. The drum fits tightly around the film 3 positioned by the emulsion layer to the surface of the drum and driven by the rotation of the drum. Recorder 4 with a blunt writing pen squeezes the groove on the film due to the bending of the film into the rubber substrate. To tension the belt 3, use the free roller 5.

The subject matter of the invention.

Claims (2)

1. A device for recording and reproducing sound on an endless tape from a film by extruding the sound groove using a transport drum, which also serves as a substrate for recording sound, characterized in that the transporting drum is covered with a rubber band around the entire cylindrical surface. 2.B) of the device according to claim 1, use for tensioning a loop of a belt of a free roller.