RU2463675C1 - Tangential pickup arm - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: tangential pickup arm has a tube mounted on a support with possibility of rotation in the vertical plane, on one end of which there is a sound-reproducing head with a needle, and a counterweight on the other. According to the invention, the pickup arm is provided with a cuvette with liquid and a float which floats on said liquid, on which the support of the tube is mounted, wherein the float is provided with rollers which interact with the inner surface of the wall of the cuvette, where the vertical axes of said rollers are attached to the float, as well as fixing devices for fixing its position, attached to the surface of the float and interacting with a guide mounted on the inner surface of the wall of the cuvette.

EFFECT: high accuracy of operation by providing uniformity and horizontality of movement of the pickup arm, reduced external forces acting on the pickup arm.

4 cl, 2 dwg

Description

The invention relates to equipment for analog playback and can be used to play gramophone records.

To assess the novelty and inventive step of the claimed solution, we consider a number of well-known technical means of a similar purpose.

In the early 90s of the last century, there was a sharp decline in the production of phonograph records due to the cheapening of compact discs and equipment for their reproduction. Some skeptics predicted death as a sound carrier. Many factories that released records shut down production or reprofiled. Manufacturers of equipment for reproducing phonograph records also almost curtailed the release of equipment. However, this medium has not died, and sales of gramophone records are currently growing. This is not only due to DJs for whom the record is the most convenient source of sound. Many artists, along with CDs, began to release their albums on gramophone records again. Industry was not slow in responding to this phenomenon. If four years ago on the market there were no more than a dozen models of record players, now there are more than fifty of them.

One of the most important parts of a turntable is the tonearm. At first glance, this is a fairly simple device that should only provide movement of the pickup head. However, it is not. The design of the modern tonearm is based on overcoming a number of technical contradictions. The tonearm should have an extremely lightweight suspension, allowing it to move smoothly with absolutely no effort. In addition, it should have a minimum inert mass. On the other hand, it should not have its own resonances in the field of sound frequencies, so that even the lowest-frequency needle vibrations during the reproduction of a record do not lead to tonearm vibrations.

There are two types of tonearms: rotary and tangential.

The turntable is currently equipped with most turntables. This is due, first of all, to the fact that such a design has a gyroscopic suspension and is much cheaper.

Almost all modern DJ turntables are equipped with Technics rotary tonearm, or its exact copy. Exceptions are only High End class players, which are equipped with own-developed tonearms. Nevertheless, the design, invented by engineers for Technics, is considered one of the most successful, despite the fact that it was developed more than 25 years ago.

Rotary tonearms are characterized by a follow-up error. This error is compensated by turning and moving part of the arm. Such tonearms are in the form of the letter "J" or "S". For modern tonearms, the horizontal angle of correction is 20-27 degrees, which ensures a minimum following error. Because of this displacement, an effect called rolling occurs, which tends to shift the tonearm to the center of the record being played. To compensate for this, special anti-skating mechanisms are used. If the anti-skating is not correctly adjusted, the needle will exert unequal pressure on the inner and outer surfaces of the groove, which will inevitably lead to signal distortion.

The tangential tonearm, in addition to a more complex mechanical system, can have a rather complex electronic circuit that provides control of its position and controls the servo drive, which moves it during playback of the record.

It is obvious that tangential models lack the drawbacks of lever tonearms - tracking error and rolling. Since the entire tonearm moves, and not just its one end, the relative position of the needle and groove is the same both during recording and during playback, and does not depend on the radial position of the needle. And since there is no tonearm correction angle, there is no rolling force.

Tangential tonarms have a much more complex design and, accordingly, a higher cost than lever ones. The entire device should move along the groove in a tangential direction with respect to the plate, which is a rather complicated engineering task.

Players of medium quality level are known in which the tangential tonearm is moved using an automated drive, the movement of which may not always correspond exactly to the recording step, i.e. the distance between the sound grooves, see http://rw6ase.narod.ru/000/rez1/elektronika_b1_04s.html.

In these tonearms, the pickup needle presses on one side of the groove more than on the other. Although you can try to correct this error, all the same follow-up drives are basically designed so that the error can be corrected only after it has arisen.

High-end tangential tonearms are known in which an air bearing is used, see http://www.audiogallery.ru/item/8608/. The tonearm hovers in a stream of air surrounding the tube along which it moves; in order to move the tonearm from the place, the lightest effort is enough, which comes from the movement of the pickup needle on the plate. Thanks to the use of an air bearing, the friction between the tonearm and the tube is reduced to almost zero. The disadvantage of supplying air to the fixed tube is the different and constantly changing air pressure along the edges of the moving tube, which leads to uneven movement.

This drawback is eliminated in tonearms with air supply to a moving tube, see http://www.fonograf-hifi.ru/catalogue/426/, http://www.inthouse.ru/VYGER/Atlantis/Atlantis.html, http : //www.recordplayer.com/en/turntable/aeroarm/specifications.html.

However, these tonearms have another drawback - the spring action of the air supply tube begins to act on the moving part. At the same time, when pressure is applied, the tube tends to straighten, the spring action increases, which negates the advantages of such an air supply.

The disadvantage of air bearings is the presence of a pump for air, as well as air supply hoses. In addition, air must exit between the tonearm and the tube. Sealing this joint will cause friction. For this reason, the accuracy of these nodes is very high, and accordingly, their cost is high. The air outlet leads to acoustic noise, they can get on the needle through the tube of the arm and amplify in the amplifier. Air bearing tonearms require very precise horizontal positioning. When skewed, the weight of the tonearm will tend to shift the tonearm toward the slope, creating harmful pressure on the needle.

Known tangential tonearms driven by a needle moving along a string, see http://www.kinohouse.ru/catalog/item/4733/.

This tonearm in terms of a set of similar features and the result achieved using the selected as a prototype.

The disadvantage of the prototype is that friction reduces the accuracy, the needle with the eccentricity of the plate fluctuates noticeably in the head, which leads to additional distortion.

The objective of the invention is to ensure uniformity and horizontal movement of the arm, reducing extraneous forces acting on the arm.

The essence of the claimed invention is expressed in the following set of essential features, sufficient to achieve the above result.

According to the invention, the tangential tonearm containing a tube mounted on a rack with the possibility of rotation in a vertical plane, at one end of which there is a sound-reproducing head with a needle, and at the other a counterweight, is characterized in that it is equipped with a cell with a liquid and a float floating in this liquid, on which the tube stand is fixed, while the float is equipped with rollers interacting with the inner surface of the cell wall, the vertical axes of which are mounted on the float, as well as with its position fixers, mounted on the surface of the float and interacting with a guide attached to the inner surface of the wall of the cell.

This is the totality of the essential features of the invention, providing the desired result in all cases to which the requested amount of legal protection applies.

In addition, the claimed technical solution has a number of optional features, namely:

- the tonearm can be equipped with a means to maintain a constant level of fluid in the cell;

- the cuvette can be equipped with a drain valve to ensure transportation conditions;

- the cuvette may be equipped with a cover protection provided with a slot for the stand.

The applicant has not identified sources containing information about technical solutions, the combination of features of which coincide with the combination of distinctive features of the claimed utility model.

The technical result achieved by implementing the totality of the essential features of the invention is that the float moves, perceiving the efforts from the needle, strictly horizontally, uniformly, silently, smoothly and at full speed due to free floating in suspension in the liquid in the cuvette the absence of backlash, which creates ideal conditions for the operation of the needle of the sound reproducing head. At the same time, the possibility of any traditional tonearm adjustments is provided.

The essence of the claimed technical solution is illustrated by drawings, where Fig. 1 schematically shows a cross-section through the claimed device, and Fig. 2 is a top view of the claimed device in the operating position during the reproduction of the gramophone record.

The tangential arm contains a tube 1 mounted on a rack 2 with the possibility of rotation in a vertical plane. A sound reproducing head with a needle 3 is placed at one end of the tube 1, and a counterweight 4 is provided at the other. The tonearm is equipped with a cuvette 5 with a liquid and a float 6 floating in this liquid, on which stand 2 of the tube 1 is mounted. The float 6 is equipped with interacting with the inner surface of the cuvette wall 5 rollers 7, the vertical axis 8 of which is mounted on the float 6. The float 6 is also equipped with latches 9 of its position, mounted on the surface of the float 6 and interacting with a guide 10 attached to the inner surface of the wall of the cell 5. Ig La 3 moves in the grooves of a gramophone plate mounted on a rotating disk 11. To improve the operating conditions of the claimed tonearm, it can be equipped with a means to maintain a constant liquid level in the cell 5, which in turn can be equipped with a drain valve to ensure transportation conditions and cover protection equipped with a slot for rack 2.

The tangential tonearm works as follows.

The needle 3 is located on the radius of the plate, a cuvette 5 is located parallel to this radius. The counterweight 4 provides the necessary pressure on the needle 3 in accordance with the technical data of the sound reproduction head. The float 6 is in a free suspended state in the cell 5 and has some margin of buoyancy. The friction force arising from the pressure of the needle 3 on the clockwise rotating plate mounted on the rotating disk 11 is sufficient to press both rollers 7 of the float 6 against the wall of the cell 5. The float 6 floats in a liquid whose resistance to the slow movements of the float is insignificant. To unconditionally and confidently press both rollers 7 against the wall of the cell 5, the center of gravity of the float 6 with other tonearm design elements mounted on it, namely, stand 2, tube 1, a sound-reproducing head with a needle 3, counterweight 4, should be located above the center of the float 6 or closer to the counterweight 4. Since the rollers 8 are provided with free rotation on their vertical axes 8, the float 6 can move parallel to the radius of the plate. The rack 2 and the horizontal axis of rotation of the tube 1 tonearm fix the tube 1 perpendicular to the direction of movement of the float 6, allowing you to work out vertical irregularities of the plate without movement of the float 6. The latches 9 during the stroke of the float 6 do not touch the guide 10 and do not interfere with the movement of the float 6. Thus, when the needle 3 is displaced along the spiral groove of the plate rotating on the disk 11, the float 6 will move with the needle 3, ensuring the tube 1 is perpendicular to the radius of the plate, which is required from the tangential tonnarm. When removing the tonearm from the plate, the latches 9, interacting with the guide 10, prevent unnecessary movements of the float 6.

The claimed technical solution provides the following advantages over all known solutions of a similar purpose:

- lack of elements consuming energy, except for the energy of the movement of the needle;

- horizontal movement of the float;

- smoothness and accuracy of the float, almost complete absence of backlash;

- the possibility of any adjustments to the tonearm;

- silent operation;

- damping of any disturbances of the tonearm by the liquid in the cell.

The claimed tangential tonearm is simple and cheap to manufacture. The existing models of the tonearm demonstrated the excellent quality of its work and sound.

The possibility of industrial application of the claimed technical solution is confirmed by the known and described in the application means and methods by which it is possible to carry out the claimed invention in the form described in the formula. The claimed device can be implemented industrially using known technical means.

Claims (4)

1. A tangential arm containing a tube mounted on a stand with the possibility of rotation in a vertical plane, at one end of which there is a sound-reproducing head with a needle, and on the other a counterweight, characterized in that it is equipped with a cell with a liquid and a float floating in this liquid, on which the tube stand is fixed, while the float is equipped with rollers interacting with the inner surface of the cell wall, the vertical axes of which are mounted on the float, as well as its position fixers mounted on top awns float and cooperating with the guide attached to the inner surface of the cell wall. 2. The tonearm according to claim 1, characterized in that it is equipped with a means for maintaining a constant liquid level in the cell. 3. Tonarm according to claim 1, characterized in that the cuvette is equipped with a drain valve to ensure transportation conditions. 4. Tonarm according to claim 1, characterized in that the cuvette is provided with a protection cover, provided with a slot for the rack.