Maybe Not Everyone Knows That ...
Spring: a ppare around XV century in clocks, replacing the system of weights that normally allowed their operation;
with the spring-loaded mechanism, the watchmakers were able to accomplish
precision instruments capable of keeping time.
In the Madrid Code of Leonardo da Vinci , dating back to the end of the fifteenth century, the use of a spring as an element is foreseen elastic .
In the Madrid Codex, Leonardo designs and studies numerous mechanisms to obtain different types of motion, often without a specific purpose and only to explore the possibilities of mechanical science.
They are studies of simple machines, evolutions or different ways to obtain the development and transmission of motion.
Some of these mechanisms are powered by a spring-loaded helical gear motor.
On the fourth page of the manuscript we find the first system with a motor that makes use of the use of springs:
the spring motor with helical transmission.
This mechanism assumes that a charged spring yields its maximum force at the beginning and becomes weaker and weaker as it discharges.
This force is defined by the value of stiffness R, expressed as force / space. The final aim is therefore to make this energy transfer linear and constant.
The particular type of spring, designed by Leonardo for this application, is still widely used today (for example in shutters, handles and drill presses) and is still called "Archimedes' spiral spring", as it is based on the concept archimedeo.
Returning to the theme, this object, 400 years after its invention, became the kinetic energy of both phonographers and gramophones.
Music box: the official history of the carillon begins in 1796, when the Swiss watchmaker Antoine Favre perfected the concept of musical devices of reduced dimensions.
To begin with, toothed wheels were used to strike the specially tuned metal blades; later these wheels were replaced by more practical and stable toothed cylinders.
At that time the manufacture of music boxes was handcrafted.
The parts, in fact, were performed manually by home craftsmen. The latter were often farmers who took advantage to earn a little with a 2nd job.
The musical mechanisms were then assembled and inserted into the caskets (music boxes) by other people hired by the manufacturers themselves. Around 1820 the idea was to replace the segmented plates with a comb or keyboard made of a single axis to increase the resonance. The most important improvement was later the invention of dampers whose function was to limit the vibrations of the blades. These dampers were initially constructed from chicken feathers.
Around 1875, Charles Paillard, the Nicole brothers and many other Swiss manufacturers began producing music boxes industrially. The methods changed and the miracles of industrialization made it possible to invent machinery capable of reproducing cylinders in large quantities and at low costs and to compete with French production.
Other innovations aimed at accentuating the rhythm of the melodies and making the music boxes richer, from the point of view of sound performance.
The most coveted musical boxes are now composed (such as phonographs and gramophones) of wood and metal and of rollers capable of containing more "musical sculptures" (high reliefs), that is, more melodies (even 8 for example) using the sound box of the box itself and a relative selection and start / stop mechanism.
Phonoautograph: invented by the French Édouard-Léon Scott de Martinville , was patented on March 25, 1857. The phonautograph was the first instrument capable of "writing"
the sound, that is to give it a different graphic representation.
Previously, traces of the vibratory motions produced by were obtained tuning fork and other objects, but not sound waves that propagate through air or other media.
It was only able, however, to trace sound waves such as undulations or other deviations in a line drawn on blackened paper or glass. carbon black .
Intended exclusively as a laboratory instrument for the study of acoustics , it may have been used to study and visually measure the amplitude and sound waveform of words and other sounds or to determine the frequency of a given musical intonation for comparison with a simultaneously recorded reference frequency.
The "recordings", called phonoautograms, for the above, could not contain information such as to allow their re-transformation into the main source (input). Since the plot was a phonautogram consisting of a two-dimensional line, direct physical reproduction of the sound was impossible in any case.
For the above, this enlightening invention did not generate a reversible writing process: no drawing, in fact, could have gone back to being a “vibration and then a sound.
For this reason we had to wait a few more years for the arrival of Edison's Phonograph.
Phonograph: Edison announced the invention of the phonograph on November 21st 1877 and on 6 December of the same year he gave a practical demonstration to his collaborators.
They were faced with an object consisting of a brass roller ( phonograph cylinder ) whose surface was covered with a sheet of tinfoil.
During recording, the cylinder rotated and the foil was touched by the stylus attached to the vibrating membrane. The stylus, following the oscillations of the membrane, engraved a deep trace in the foil which, stretched over the groove, could yield under the pressure.
For reproduction, the process would have been reversed, with the only difference that in this case a second membrane, much more elastic, was used, placed at the other end of the device. The groove in the foil with its variations in depth, it made the membrane vibrate, returning the recorded sound. The operation was therefore alternatively of recorder or reproducer.
Edison thus began to turn the crank that set the system in motion and speaking in the direction of the diaphragm he hummed
" Mary had a little lamb ". Once the cylinder was brought back to its starting point, he placed the needle on the second membrane in the groove imprinted in the foil by the first, resumed turning the crank and the phonograph repeated a sound vaguely similar to the phrase pronounced just before. The quality was bad, but the foundations for an epochal change had now been laid.
February 19 1878 Edison got the patent of his own invention and together with some financiers he created the "Edison Speaking Phonograph Company", to install it in the country fairs and in the funfair , where the public could make it work using tokens. This choice was made in light of the need to further improve the quality of the recording before it could become really useful for the offices for which Edison had designed it.
In this way one could begin to exploit the curiosity created by the novelty and begin to spread a certain knowledge of the possibilities of the new invention.
Edison saw a future for the phonograph, not so much for recording music, but above all for dictating letters in offices, creating books for the blind and teaching diction. Indeed, without knowing it, he had hypothesized the first answering machine , here is one of his thoughts: "A telephone subscriber can install a phonograph on a device which, at each call, will notify the central office that he has left, and that he will be back at a certain time. In the same way a subscriber, calling another and not finding him at home, will be able to make his communication and record it on the phonograph of the person called ".
This purely "professional" orientation of the Phonograph was justified by the fact that Edison counted on the existence of thousands of offices which its invention would allow to increase profits by reducing the time needed to complete certain operations. Music recording, on the other hand, would have been a totally new market and Edison, who a few years earlier had been "burned" by the failure of his innovative electronic voting system, was no longer willing to take risks by betting resources on an unknown world. .
Gramophony
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