DE3243503A1 - FLAT TURNTABLE PICKUP ARM - Google Patents

Description

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TESLA koncernovy podnik Prague, CSSR

Flat turntable pickup arm

The invention relates to a turntable pickup arm, in particular for turntables of the "High fidelity "class.

Currently known turntable pickup arms of this quality are available in various mechanical Execution made. However, they are currently being made as stiff and strong as possible in all directions, about their natural vibrations and thus also unwanted natural resonances in the acoustic and subacoustic range to limit as much as possible. The requirements mentioned have so far been best met by a pipe that has a support element of all known arms for cartridges of this class. Growers strive to get the total weight to reduce these tubes and so also the whole pickup arms as possible, as this weight is one has a direct influence on the undesired lower resonance of the tonearm, the frequency of which is due to the flexibility of the stylus holder of the respective cartridge and the effective weight of the cartridge arm will. Modern pickup arms of the quality class mentioned usually have a small vertical force

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the needle point, which today seldom exceeds 20 mN, and also a very flexible needle carrier. It is therefore necessary to keep the weight of the pickup arm small enough to achieve the lower resonance maximum is not too low, as the bandwidth between 8 and 12 Hz is based on many years of experience was determined to be optimal for the lower resonance of pickup arms of this class. It is demonstrated that turntables with built-in pickups that resonate in the optimal range around 10 Hz vibrate, withstand vibrations better than pickup arms, whose lower resonance is lower than with 8 Hz. With these low subacoustic vibrations occur z. B. Vibrations of buildings, of floors and furniture caused by traffic or footsteps and also vibrations caused by uneven, very curled records are often produced. Although these unwanted components are outside of the audible Area are, they can nevertheless noticeably influence the quality of the reproduced sound in that So above all the signal-to-noise ratio, the ability of the pick-up needle and the values of the intermodulation distortion of the useful signal are deteriorated. That is why lately there is an increased level of attention the suppression of unwanted resonances in the subacoustic range, using various dynamic Dedicated to vibration dampers or anti-resonators, which are common along with oil damping systems, possibly also work with arrangements for adjusting the vertical force on the needle tip of the turntable pickup arm.

A certain reduction in the undesirable lower resonance maximum is used in currently known mechanical

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Solutions either by applying an effective damping in the vicinity of the pickup arm by a vibrating Antiresonator or dynamic vibration damper on the rear part of the pickup arm at the counterweight or achieved by combining these two basic measures. In practice, however, it is difficult to find one To form a pickup arm whose unwanted resonance is optimally dampened in all directions. A vote a possible anti-resonator on the frequency of the lower resonance is also not clear; because the Most of the pickups have a stylus holder with different flexibility in the vertical and horizontal Direction, so that the lower resonance of tubular arms usually has two pronounced maxima at different Has oscillation numbers. Disadvantages of these mechanical solutions are, to a large extent, of the pickup arms fixed in the highest price category, which are based on the electronic and electrodynamic principle and their movements and resonance controlled by a complicated electronic system with a servo loop will. All of these known cases with a similar solution are expensive individual products, which are only produced in small series for a small group of special customers. In practice only mechanical solutions of anti-resonators or vibration dampers come into play for which a mechanical resonance circuit is essential, which consists of a compliant element, e.g. B. a steel spring, and from a weight, e.g. B. part of a counterweight. The task of the dynamic vibration damper is to reduce the lower resonance maximum, this is the result of the interaction of the weight of the arm and the resilience of the built-in needle holder Pickup is. A correct way of working

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of the dynamic vibration damper is based on the fact that the largest possible part of the weight of the counterweight, which is resiliently arranged on the rear part of the pickup arm behind the support bearing, at a Vibration number begins to vibrate that is equal to that is undesirable lower resonance maximum. Since the dynamic vibration damper oscillates in opposite phase, it is reduced its effect reduces the amplitude of undesired vibrations and thus acts as an anti-resonator for the pickup arm. · This also increases the resistance of the entire turntable to vibrations increased in the subacoustic range.

The dynamic vibration dampers acting in all directions, usually as part of a counterweight executed, but are difficult to execute for production, especially with regard to the effect the gravity, which influences the operation of an anti-resonator in the vertical direction and therefore a complicated one Compensation for achieving a sufficiently stable position of the counterweight is conditional. There is also a change of mind such anti-resonator systems on the number of vibrations of the lower resonance maximum of the pickup arm very difficult and practically impossible for the user. The requirement to use the largest possible part of the weight To set the counterweight in vibrations is currently known solutions in all directions act, practically impossible to achieve, where with dynamic vibration dampers only a smaller part of the total weight of the counterweight can swing. Therefore, even with optimal setting, the optimal number of vibrations a sufficiently great suppression of the undesired lower resonance is not achieved, even at very expensive pickup arms no lower maximum than 10 dB for any number of vibrations in the subacoustic

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see tape owns. Classic tubular tonearms, on are already expensive to manufacture if an anti-resonator is designed that acts in all directions or a vibration damper system technically and in production even more demanding, so that they only for the highest price brackets. A typical example is a set of five pickup arms with different effective weights, of which one is the most suitable for a given cartridge selects according to the flexibility of the needle holder with the needle. Has such an exclusive solution however, of no practical significance for the common user and music listener.

The arrangement for adjusting the vertical force on the stylus tip of the pickup is usually at the rear Part of the pickup arm behind its support bearing, usually attached as part of the counterweight, the main purpose of which is to balance the weight of the front part with the built-in pickup and are an achievement of equilibrium. The required vertical forces on the needle tip are achieved by that the whole counterweight or its part along a thread out of equilibrium in Direction against the support bearing is shifted until the front part with the pickup is overweight achieved the required vertical force on the needle tip according to a scale and an indicator on the weight.

Some pickup arms only give the rear counterweight a balancing function to achieve it a state of equilibrium, where the vertical force

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on the tip of the needle either by a sliding weight on the front part of the pickup arm or by one arranged in the vicinity of the bearing for the vertical oscillation movement of the pickup arm Spring is achieved.

A disadvantage of classic solid pickup arms, which are made from tubes with a sufficiently low weight are to match high quality pickups with very compliant stylus holders is also the fact that they are usually very expensive; because their production requires special materials and processes, such. B. various alloys of aluminum, titanium and, more recently, various laminates, e.g. B. are stiffened by glass or carbon fibers. But despite all the arrangements mentioned, they are also very stiff Tubes made from these materials have a certain, albeit slight, resilience in practically all of them Directions on. This is why the lower resonance of classic tubular tonearms is almost the same in vertical and horizontal direction when measuring, both when recording at the bottom of the tone groove, when measuring in the horizontal direction with recording on the floor and on the side, as well as with a recording below an angle of 45 ° when measuring stereophonic recordings in the left and right channels on the sides the tone groove are provided. Since there is a resonance in all directions, it is difficult to to master and attenuate them in a really effective way that is economically viable, practically at all executable and suitable for use. Currently known and practically implemented solutions for tonearms are therefore always either a compromise for one

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relatively affordable price or exclusive, complicated and so expensive that their price sometimes includes the price by all high fidelity turntables.

Known dynamic vibration dampers of classic tubular pickup arms have a basic one Disadvantage in that they are incapable of vibrating equally in all directions, like those in all of them Direction-acting resonances from tubular pick-up arms. Another fundamental disadvantage currently known dynamic vibration damper is the fact that it is because of the necessary mechanical backup Stability of the counterweight system is not possible, the entire weight of the counterweight can be stored flexibly, but only its small part. The influence of a dynamic vibration damper designed in this way on decreasing the lower resonance maximum is small; because only a small part of the counterweight swings , while it would be necessary for maximum suppression of the unwanted resonance, if possible to vibrate the whole weight of the counterweight. Known dynamic vibration dampers can adjusted to the number of vibrations of the lower resonance only experimentally or by repeated measurements will; because there is no clear aid or an arrangement that would allow the optimal Number of vibrations and the optimal damping factor as specified by the manufacturer of the tonearm concerned and the built-in pickup. If the number of vibrations and the damping are not set correctly are, the effectiveness of the vibration damper is significantly reduced.

Various disadvantages of arrangements for adjusting the vertical force on the needle tip have also commonly used rotatable or slidable counterweights, which are equiaxed on the rear part of the Tube of the pickup arm are stored by moving them out of equilibrium in the direction the required vertical force is set against the bearing. Although this procedure is simple in principle, however, the practical solution is more complicated if one is concerned with the high center of gravity a coaxially arranged counterweight achieve a stable state of equilibrium and likewise the demand for an easy, clear setting that is resistant to undesired interference to meet the vertical force. In particular, it is very difficult to have a counterweight arranged in this way to complement an anti-resonator that is effective in all directions.

Sometimes a small weight is attached to the front of the tonearm to adjust the vertical force is used, but undesirably increases its effective weight.

Disadvantages also have arrangements with springs for adjusting the vertical force, the value of which is connected to one Scale is read. Arrangements with springs are usually more complicated and manufacturing more demanding, and with a possibly very simple structure, they are not very precise.

The invention is based on the object of developing a flat turntable pickup arm,

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whose lower resonance maximum is in the desired range thanks to the reduced weight, that with the portable Effort can be produced and its assembly and operation are simple.

The invention, with which this object is achieved, is a flat pickup arm in the form of a Plate with openings for elements for a mechanical and electrical connection of the pickup arm with the Pick-up with the turntable, marked that the flexible front longer part and the shorter one rear part of the pickup arm with a row of auxiliary elements, d. H. with openings and / or cutouts for attaching, possibly also for making accessible work elements on the pickup arm and for Influencing its mode of operation is provided, with at least one of the two surfaces of the pickup arm at its front longer part with electrically conductive connections from the pickup to open for Elements for electrical connection to the turntable are provided, at least at the level of the lower Surface of the pickup arm are arranged.

The top surface of the pickup arm can be provided with at least one electrically conductive connection forming the upper surface of the pickup arm towers above and from the pickup to openings for elements for an electrical connection with the turntable leads.

The auxiliary element can be in the form of at least one opening or in the form of at least one cutout in the Body of the pickup arm are formed; if necessary, the auxiliary elements are in the form of at least one opening

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and formed at least one cutout.

The end of the front longer part expediently has a bevel, the edge of which with a line parallel connecting the centers of a pair of openings for mounting the cartridge.

The front longer part of the pickup arm is advantageously provided with an opening for a locking element for the pickup arm in its rest position.

On the shorter rear part, the pickup arm can have at least one opening for reaching a Flexibility of this part should be provided in the vertical direction. The pickup arm can be used for the same purpose with at least one section or with a combination of a section and at least be provided with an opening.

The rear part of the pickup arm can either be in a longitudinal direction with a toothing Opening or on one of the longitudinal edges of the pickup arm. The gearing can be used as part of the Body of the pickup arm or be designed as an independent additional part.

At least one surface of the front longer part of the pickup arm can be electrically conductive Connections from the cartridge to openings for elements for an electrical connection to the turntable be provided at least partially with a conductive coating.

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ORIGINAL INSPECTED

The electrically conductive coating and the conductive ones Connections from the cartridge to elements for an electrical connection with the turntable can be formed as foils.

The electrically conductive connections from the cartridge to elements for electrical connection with the turntable can also be carried out in the body of the pickup arm.

At least one surface of the longer front part of the pickup arm can at least partially with an insulating film with a conductive coating with conductive connections from the pickup to openings for elements for an electrically conductive connection to the turntable.

The shorter rear part of the pickup arm can be provided with at least one stiffening element for heightening the rigidity of the adjacent part of the pickup arm in the vertical direction.

The pickup arm can be formed from either a flat insulating plate or a flat metal plate are optionally composed of at least one metal plate and at least one layer of insulating material be.

On the shorter rear part of the pickup arm is an element for adjusting the vertical force on the The needle tip of the pickup is arranged, its pinion with the toothing in an opening in the rear shorter Part of the pickup armGS is in engagement, wherein

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on the movable and rotatable element for adjusting the vertical force on the stylus tip of the pickup a counterweight system is rotatably connected.

Part of the counterweight system in the form of a
dynamic vibration damper is expediently formed by a carrier, which with the displaceable and rotatable element for adjusting the vertical force on the needle tip of the turntable pickup
is connected ', with an upper horizontal part of this beam against at least one stiffening
and / or guide element on the lower side of the
shorter rear part of the pickup arm
and a vertical part of this support is provided with a bearing for a swinging arm to which the actual body of the counterweight is fixed and the free part of the swinging arm is supported by a helical compression spring, the other end of which is attached to a lower fixed horizontal part of the support is attached.

A regulating screw is advantageously mounted on the swinging arm, which turns from top to bottom the helical compression spring engages, the pitch and the diameter of the turns of this helical compression spring in by the weight of the swinging arm with attached body of the counterweight when compressed, correspond to the pitch and the diameter of the turns of the regulating screw.

The body of the counterweight, which is mounted on the swinging arm, is advantageous on the pressure

The side facing the spring is provided with a scale for setting the number of resonance vibrations.

A transparent container that contains a damping medium can be mounted on the swinging arm, above which there is a regulating screw for setting the damping factor. This regulating screw is usually part of the element for adjusting the vertical force on the needle tip of the turntable cartridge . The regulating screw leads into the transparent container through a through opening in the swinging arm and is connected to the non-swinging part of the counterweight system.

The inner wall of this through opening for the regulating screw is expediently widened downwards in such a way that that between this wall and the wall of the transparent container there is a collecting space for the Forms damping medium, which is greater than the content of the damping medium in the transparent container. Of the The body of the counterweight attached to the swinging arm can face the transparent container Side be provided with a scale for setting the damping factor. Otherwise this scale can also be provided on the wall of the transparent container.

The main advantage of the flat pickup arm according to the invention in the form of a plate is that it is practically rigid in the horizontal direction while the flexibility of which can be selected in the vertical direction. This has the following advantages:

- By appropriately selected flexibility of the front longer part of the pickup arm in the vertical direction

Direction can its effective weight compared to known stiff pickup arms about a quarter are reduced, which advantageously increases the number of oscillations of the lower resonance maximum;

- The production of flat pickup arms in the form of a plate is much cheaper than that of classic ones tubular tonearms; because they can be punched from flat material of various types and, if necessary, entirely according to them the process of making printed wiring;

- the arrangement of working elements on the flat pickup arm, ζ. B. the connection socket for electrical and mechanically connecting to the storage system of the turntable, the elements for securing the Pickup, for mechanically locking the arm in the rest position and for attaching the counterweight system is easy and cheap;

- to dampen the undesired lower resonance, a dynamic vibration damper can be used, which only acts in the vertical direction. The solution such a damper is light in weight and inexpensive, and so is the resonance frequency and the damping factor thereof can be easily adjusted according to the pickup applied regardless of the vertical force on the stylus tip will;

- the mode of operation of the dynamic vibration damper in conjunction with the flat pickup arm is only limited to swinging in the vertical direction; because the flat pickup arm has none

Compliance in the horizontal plane, eliminating the need for the lower horizontal Suppress resonance. By restricting the swing of the counterweight to the vertical direction, at the same time allows the entire weight of the counterweight to vibrate, which is a Vibration in all directions is practically impossible on currently known dynamic vibration dampers. With this arrangement, a maximum efficiency of the dynamic vibration damper is achieved;

- Another advantage of the flat pickup arm is the possibility of a mechanical and in the Manufacture of a simple arrangement for adjusting the vertical force on the stylus tip of the pickup; because the rear part of the pickup arm can be arbitrary shaped or optimally prepared for storing the required work items. The flat pickup arm allows the counterweight to be advantageously positioned underneath to arrange its lower surface, regardless of its own element for adjusting the vertical Force provided on the upper surface of the pickup arm. This brings the focus of the Counterweight in an optimal low position opposite the support bearing for the vertical oscillation movement of the Pickup arm, so that a stable state of equilibrium can be easily achieved.

An example embodiment of the flat turntable pickup arm according to the invention is shown in the following is described in more detail with reference to the drawings; show in it:

Fig. 1 is a side view of an arrangement of a flat pickup arm, the by a support bearing for a vertical oscillating movement in a front part with an indicated pickup and is divided into a rear part with an indicated counterweight;

Fig. 2 · a view from below of the pickup arm according to FIG. 1, where in the front Part two openings for attaching the pickup and one opening for one Locking element is provided in the rest position of the pickup arm and openings for elements for in the bearing axis an electrical and mechanical connection between the pickup arm and the Turntables are provided with the end of the pickup arm having a bevel possesses that with the line connecting the centers of the openings to the Attaching the pickup is parallel, and the rear part of the pickup arm is provided with an opening for attaching and operating the counterweight;

Fig. 3 shows an arrangement of the front part of the

Pickup arm in the same view as FIG. 2 with further possible openings for work items;

Fig. 4 in the same view, the front end of the

Pickup arm as in Fig. 2 and 3, where the line connecting the centers of the openings for fastening elements for the pickup with the bevel of the front end of the pickup arm parallel is;

Fig. 5 is a view of the rear end of the pickup arm with an elongated opening, which is provided with a toothing;

6 shows the same view as in FIG. 5 with further elongated openings;

Fig. 7 shows the rear end of the pickup arm

with one or two-sided cutout with a toothing in the longitudinal direction and with openings arranged in the transverse direction;

Fig. 8 shows an arrangement of the rear part of the

Pickup arm, as in FIG. 7, with a spur provided with a toothing;

Fig. 9 shows an arrangement of the rear part of the pickup arm with a system of openings with indicated counterweight;

Fig. 10 shows an arrangement of the rear part of the pickup arm with a "U" -shaped Opening and two cutouts from behind and indicated counterweight;

Fig. 11 shows an arrangement of the rear part of the

Pickup arm with two cutouts lying across from one another with indicated Counterweight;

12 shows an arrangement of the rear part of the pickup arm with an opening and a narrow spur with an indicated counterweight;

Fig. 13 shows an arrangement of the rear part of the

Pickup arm in side view with a cutout for a reduction in the Cross-section in the transverse direction;

14 shows an arrangement of the rear part of the pickup arm in a side view a stiffener attached to the lower surface of the cartridge is;

15 is a side view of a dynamic

Vibration damper and an element for adjusting the vertical force the stylus tip of the pickup on the rear part of the pickup arm in part Cross-section? and

Fig. 16 is a plan view of the rear part of the Pickup arm with an elongated opening with teeth on one side, in which is a pinion of a rotatable element for adjusting the vertical force on the stylus tip of the pickup intervenes.

The flat pickup arm 1 according to FIG. 1 has the shape of a plate, which has a natural resilience has in the vertical direction, while their compliance in the horizontal direction is practically zero. The axis of the support bearing X of the pickup arm 1 for its vertical oscillatory movement divides it into a longer front part L, at the end of which a pickup C is arranged by means of fastening elements can be, and in a shorter rear part W, on which a counterweight system 4 is provided.

The pickup arm 1 is at its longer front part L and at the rear shorter part W, as well as at the point of the support bearing X with auxiliary elements 11 for fastening, possibly to enable access to working elements that are attached to the pickup arm 1, and to influence its properties provided in operation. These auxiliary elements are in the shape of circular or elongated or other openings or lateral and / or deep cutouts or incisions that are in Combined or used for various purposes depending on the required properties of the pickup arm can be. At the location of the support bearing X, the pickup arm 1 has four openings 11d, as in FIG. 2 is indicated for pressing in bolts that have a four-pole fork connection for insertion into a four-pole Form socket on the support bearing X for the vertical swinging movement of the pickup arm 1 at its Pivoting post is arranged to be pivotable.

The longer front part L of the pickup arm 1 has at its end a bevel 12, the edge of which is circular with the line connecting the centers of two Openings 11a for a fastening element of the pickup C is parallel. These openings 11a can also opposed to an elongated shape in the vertical direction

the mentioned connecting line, so that they have a shifting of the pickup C forwards during installation or backwards for a possible setting of the protrusion of the needle tip of the pickup C. The bevel 12 is chosen to be parallel to the front of the built-in pickup C. so that they can be used in practice as a visual aid for inserting the tip of the needle onto the record R (Fig. 15) is used. The opening 11b in the front longer part L of the pickup arm 1 is for fastening a bolt or other locking element in the rest position of the pickup arm 1, where this element is clamped in a locking stand of the pickup arm.

Fig. 3 shows a pickup arm according to FIG. 2, on the front longer part L for the purpose of reaching A series of openings 11c is provided for greater flexibility in bending of this part of the pickup arm which also serve as relief openings.

On the lower surface of the front part L of the flat pickup arm 1 shown in FIG. 2 is means of the printed connection process, an electrically conductive coating 13 with conductive connections 14 in FIG a copper foil, namely between the openings 11d and soldering points 15 for connection to the pickup C. The conductive connections 14 are provided in the center while ground connections are provided in the left and right channel in the remaining part of the film 13 on the lower surface of the pickup arm 1, so that all connections are in one plane. This arrangement is not just dated manufacturing and technological Point of view advantageous, but also because they are a

free lateral adjustment of the flat pickup arm 1 in the raised position with the tip of the needle Pickup C allows above the record, not shown, where a smooth surface on the lower Side of the pickup arm 1 directly on a support element, not shown, of the starting and lifting mechanism of the turntable can be moved so that it is not necessary on the lower side of the pickup arm 1 to attach a mechanical bridging of conductive connections 14. This advantage shows also in the case of embedding the conductive connections 14 on the lower side of the pickup arm 1, where e.g. B. the insulation of embedded wire connections does not exceed the level of its lower surface.

If necessary, the natural flexibility of the front longer part L of the flat pickup arm 1 to limit, it is useful to have the upper side of the required length with a not shown To provide stiffening element that is advantageous for. B. by a semi-rigid strip conductor with four connections from the pickup C to the connector on the support bearing X can be formed.

The auxiliary elements, d. H. openings and / or cutouts 11, individually or in groups of different shapes and sizes, located in the rear shorter part W of the pickup arm 1 are provided, are used to arrange working elements of the pickup arm 1 or to increase the flexural flexibility of its rear shorter part W, possibly simultaneously for both purposes. At Pick-up arms of sophisticated designs, these openings are used primarily for arranging and making them accessible of working elements of the pickup arm 1, which the essential parts of the system 4 of the counterweight of the

Form pickup arm 1. One of those work items is an element 3 (Fig. 15) for adjusting the vertical force on the stylus tip of the pickup C, a Another working element related to this is a dynamic vibration damper. The element 3 to adjust the vertical force on the needle tip of the pickup C is common in an elongated opening 11e arranged, as shown in Fig. 5 and also in Fig. 6, where on both sides of this opening 11e elongated openings' 11g for increasing flexural compliance the shorter rear part W of the pickup arm

I are running. The opening 11e is customary on theirs one side with a toothing 111 for a pinion 31 of the element 3 for adjusting the vertical force the needle tip of the turntable cartridge C. The mentioned element 3 can, however, also in a one-sided recess 11i (Fig. 7) on the rear shorter part W of the pickup arm 1 or in a recess

II j (Fig. 8) may be provided, which is similar with a toothing 111 'is provided.

Furthermore, auxiliary elements 11 are used to form a simple dynamic vibration damper on the rear shorter part W of the pickup arm 1 at the same time Applying a simple counterweight 4 '(Fig. 13) at the end of the rear, shorter part W of the pickup arm 1 arranged for the application of one type of pickup and adjustable once and for all. Dependent on on the type of material for creating the pickup arm 1 can increase the flexural compliance its rear shorter part W a series of openings 11k (Fig. 9) or cutouts 11m or 11n, shown in Figures 10 and 11, or a combination applied from deep side cutouts 11o

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as shown in FIG. An increase in flexural compliance can also be achieved through cutouts 11p can be achieved, which is in the thickness of the Tonabnehraerarmes 1, as shown in FIG. The arrangement of the element 3 for adjusting the vertical Force on the needle tip of the pickup C on the rear part W of the pickup arm 1 is shown in FIG. 15 and 16 shown.

If the dynamic vibration damper in the counterweight system 4 has its own as a flexible element Has spring with adjustable compliance, it is advantageous, however, the rear part W of the pickup arm 1 to leave its natural stiffness or to increase it by a stiffening element 5, as indicated in Fig. 14, which is usually attached to the pickup arm 1 by fasteners that in a group of openings 11f - see FIG. 2 - arranged are.

Instead of the mentioned film 13 with etched connection patterns Any electrically conductive coating can be applied to the lower surface of the pickup arm 1 be applied, the z. B. by printing with a conductive paint, by vapor deposition of a metal and the like is executed, at the same time forming the connection pattern.

The conductive connections 14 do not necessarily have to be on the lower surface of the pickup arm 1 be carried out, as was mentioned in the exemplary embodiment, they can also be in the body profile of the pickup arm 1 embedded, e.g. B. in one carried out on the lower surface of the pickup arm 1

Groove, or they can be placed directly in the body of the flat pickup arm 1 be pressed in, if this is made of plastic, the usual by glass or carbon fibers or by a metal skeleton is stiffened, is pressed.

The flat pickup arm 1 can not only be made of plastic, such as. B. made of glass laminate and other insulating materials similar properties, but also made of metal, e.g. B. from a flat steel spring, and also as a combination of plastic with metal. In the case of a metal pickup arm, it is advisable to to provide this with an insulating film, as mentioned in the exemplary embodiment. These Insulating film with connections can be advantageous with a self-adhesive layer for attaching them to the Surface of the pickup arm. Except the aforementioned designs, it is possible to use the flat pickup arm 1 from at least one metal plate to form at least one layer of insulating material, the thickness of the layers of said materials be selected with consideration of the flexibility requirements of the flat pickup arm.

The pickup arm 1 according to the invention can be produced in various ways. One of the most beneficial Manufacturing process is a simple punching by means of a pressing machine from flat plate material, for. B. off layered glass laminate and the like. By a pressing operation can not only have the desired shape and desired work openings and cut-outs, but also the longitudinal toothing on the rear part of the pickup arm for inserting the rotatable element for adjusting the vertical Force to be formed on the stylus tip of the pickup.

The pickup arm 1 according to the invention has the front one longer part L deliberately compliant in the vertical direction, while its compliance in the horizontal direction is practically zero. The vertically yielding one front part L of the pickup arm 1 together with the resiliently mounted counterweight system 4 in the The system of the dynamic vibration damper reduces the effective weight of the Pickup arm 1. For the effective weight of the pickup arm 1, including the weight of the cartridge, the equation applies:

= M ' _p

4.12 Vl + -W-

where mean:

Μ _φ the effective weight of the cartridge arm with the cartridge (kg),

M 'is the weight of the cartridge (kg),

M ¹ _Λ the weight of the cartridge arm (kg),

L is the distance of the axis of oscillation from the stylus tip of the pickup,

W is the distance of the axis of oscillation from the center of gravity of the counterweight.

The following applies to the effective weight of the counterweight:

YES ² . _M ,

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c ⁺ 4.12

where mean:

Μ- the effective weight of the counterweight (kg),

M ' _{r is} the mechanical weight of the counterweight (kg), determined by weighing.

The coefficient of 4.12 applies to a resilient pickup arm made of one-sided glass laminate a thickness of 1.5 mm is carried out. For stiff pickup arms this coefficient is 3.00. the Values of these coefficients were determined by mathematical Analysis and modeling determined on a calculating machine.

From the conditions mentioned and through practical evaluation of a larger number of flexible pickup arms it follows that flat compliant pickup arms have a quarter less effective weight than have classic stiff pickup arms of the same mechanical weight, so that the lower resonance is advantageous is offset against higher oscillation numbers.

Since the pickup arm is in the form of a flat plate, there is practically no flexibility in the horizontal direction has, in contrast to classic stiff pickup arms, it shows practical measurements on one horizontal recording in the subacoustic range no resonance maximum. In contrast, the vertical flexibility of the pickup arm, which acts as an element of the dynamic vibration damper, to significantly reduce the usual lower resonance maximum when measuring on a vertical recording, if the number of oscillations of the vertically oscillating counter-

weight with the oscillation number of the lower resonance maximum and if the oscillation of the Counterweight is optimally damped. A balanced counterweight oscillates in resonance in opposite phase the front part of the pickup arm with the pickup, its unwanted resonance vibrations so effectively reduced. The advantageous behavior is particularly evident when measuring the lower resonance on the left and right channels of a stereophonic recording on a vinyl record, where both signals on the side walls of the groove at an angle of 45 to the vertical plane in size by a vertical and horizontal components are determined. As with a flat pickup arm in the area of the lower Resonance whose horizontal component is fundamentally absent and the vertical component due to the coordinated dynamic Vibration damper is reduced, the resulting signal, i. H. the resonance maximum in both Channels L and P, about 3 to 6 dB lower than with stiff pickup arms, especially pickups be of high quality, the needle holders are optimally damped.

The lower resonance maximum of such a damped, flat, resilient pickup arm is in both Channels flat and not very pronounced, so that the reproduction and characteristics of the turntable are audible and subacoustic range practically not influenced. The coordination of the number of vibrations and the damping of the Antiresonators, as determined by practical measurements and tests, are common to the majority of pickups not very critical. This advantage of the resilient pickup arm is practically evident when installing of pickups of different quality, where

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the vertical force on the needle tip and thus also the flexibility of the needle holder are significantly different are. Classic stiff pickup arms with more pronounced lower resonance require consideration on their own weight, a pickup with a corresponding resilience in relatively tight Range to be selected if the lower resonance should be in the optimally equally narrow range around 10 Hz. In contrast allows for a flat, resilient pickup arm with properly tuned and dampened dynamic Vibration damper and less pronounced lower resonance, practically any pickup with very different ones vertical force on the needle tip and with a different flexibility of the needle holder to build in; because if the resonance maximum is not pronounced, its own number of oscillations is practical not critical. Then it is also not necessary to produce variants of the pickup arm of different weights or to limit their optimal applicability only to certain pickups, as is usual with high-quality pickup arms classic execution is the case. The simple and clear mode of operation of the compliant Pickup arm with dynamic vibration damper, which only works in the vertical direction, makes it much easier the design and manufacture, which will be significantly cheaper than classic tubular pickup arms can.

In practical designs, most advantageously from layered glass laminate using the usual method of etched surface connections, the flat, resilient pickup arm enables simple press-fit Metal bolts both for attaching the pickup, for a rest position lock, as well as an arrangement of a

simple connection plug. This can can easily be plugged into a corresponding pivoting socket on the rotatable post, so that the whole Pickup arm is easily interchangeable and cheap for different versions of the turntable in addition can be delivered, which significantly increases its scope.

Adjustment elements of the pickup arm for the vertical force on the stylus tip of the pickup, the The number of vibrations and damping of the dynamic vibration damper can be clearly seen on the flat pickup arm and with the possibility of an independent setting also by the user z. B. according to the instructions for use or in the case of discerning discophiles, depending on a particular record that makes it possible to to find the undesired resonance maximum visually and to reduce it optimally.

At the rear part of the pickup arm 1 behind the support bearing X is in the space through the opening 11e for a displacement of the counterweight system 4 is determined, a rotatable adjusting element 3 for adjusting the vertical Force placed on the needle tip of the turntable cartridge C, as shown in Fig. 16, the with is connected to the carrier 41 of the counterweight system 4, as FIG. 15 shows. On the carrier 41 is a bearing 411 for a vertical oscillation movement of a swinging arm 412 with an attached counterweight 42 arranged, which arm 412 is supported at the other end by a helical compression spring 6, the lower end of which is supported on a horizontal lower part of the carrier 41. In a thread that is arranged in the oscillating arm 412 is, a tuning screw 7 for adjusting the number of resonance vibrations of the counterweight 42 is shown in FIG screwed in a scale 421, which is close to the

screw 7 is arranged on the wall of the counterweight 42. On the swing arm 412 is a clear container 8 attached with the displayed scale 811 with details of the damping factor. The transparent container 8 contains a damping medium 81, e.g. B. colored silicone oil, in which, if necessary, a regulating screw 32 for adjusting the damping factor according to scale 811 on the wall of the transparent container 8 can intervene. The scale 811 with details of the damping factor can also be used on the wall of the body of the vibrating counterweight 42, which faces the transparent container 8, is arranged be. The regulating screw 32 is arranged in the body of the adjustable rotatable regulating element 3 in such a way that that the operation of the rotation of the element 3 is independent. The regulating screw 32 is so tight with that non-vibrating part of the counterweight system 4 connected, which the carrier 41 and the mechanical with this connected rear part of the pickup arm 1 and the adjustable represent rotatable element 3. The inner wall of the through opening for the regulating screw 32 in the swinging arm 412 is extended downward into the interior of the transparent container 8, whereby between this inner wall and the wall of the transparent container 8, a collecting space for the damping medium 81 with a Content is formed which is larger than the content of the damping medium 81 in the transparent container 8.

The range of the number of resonance vibrations that can be set on the dynamic vibration damper is according to the effective weight of the pickup arm 1 and the compliance of the stylus holder of various types of "high fidelity" class pickups that to be considered for incorporation. For practical use, the optimal vibration control

found between 7 and 14Hz. The lowest number of resonance vibrations is determined by the difference in the length of the helical compression spring 6 for supporting the vibrating Arm 412 with the body of the counterweight 42 in the unloaded and loaded state through the vertical Force determined by the weight of the counterweight 42. The pitch and diameter of the helical The compression spring 6 in the loaded state corresponds to the mean diameter and the pitch of the tuning screw 7, which can be screwed into the helical compression spring 6 by turning or unscrewed therefrom, without the height of the body of the counterweight 42 being changed. It follows from this that it is possible by means of the tuning screw 7 up to three quarters of the turns of the helical compression spring 6 out of operation to set and so according to the scale 421 the number of resonance vibrations to the required value between 7 and 14Hz to be set.

The transparent container 8 with the damping medium 81 is with the swinging arm 412 and so too with the body of the counterweight 42 fixedly attached to the swing arm 412 so that this with resonates with it in the vertical plane. If the adjusting screw 32 for setting the damping factor is the Damping medium 81 is not touched, the damping factor of the dynamic vibration damper is zero. at Continuous insertion of the regulating screw 32 into the damping medium 81 initially leads to a slight Contact that causes the slightest damping of the vertical vibrations of the counterweight 42. With further continuous insertion of the regulating screw 32 into the damping medium 81, the value of the damping factor can easily be read according to the position of the end of the regulating screw 32, which is against the line mark in question

Scale 811 projected on the wall of the transparent container 8 will.

The arrangement for adjusting the vertical force on the stylus tip of the turntable cartridge is provided on the rear part of the pickup arm 1, which is in the direction of support bearing X with an elongated opening 11 is provided, one side of which as a tooth comb 111 is designed as shown in FIG. A tooth comb 111 'can also be at another point of the rear Part of the tonearm 1, e.g. B. on side edges or in a cutout on a side edge (Fig. 7, 8), arranged If necessary, it can also be attached to the pickup arm 1 as a separate part. At the front end of the pickup arm 1, the pickup C is attached to the needle, which is attached to the record during operation R (Fig. 15) is pressed from above by an adjustable force F. A pinion engages in the tooth comb 111 31 of the adjustable rotatable element 3, which is provided with a scale of the vertical force F, which Element 3 during the rotation along the rear Part of the pickup arm 1 moves towards the support bearing X or away from it. With the adjustable rotatable element '3, the counterweight system 4 is firmly connected to the dynamic vibration damper contains which counterweight system 4 is advantageous below the mechanical axis of vibration of the flat pickup arm 1 in order to achieve a is arranged optimally stable equilibrium. When rotating the adjustable rotatable element 3 is also the counterweight system 4 moved.

The flat pickup arm 1 with the attached sound

BATH ORIGINAL

customer C on its front part and with the dynamic Vibration damper and the element 3 for adjusting the vertical force on the needle tip of the turntable cartridge the rear part is electrically and mechanically in operation by means of four socket pins connected to a socket, not shown, which is pivotably mounted on the rotatable post of the turntable is. The needle tip of the pickup C, by means of an optimal force through the element 3 for adjustment loaded by the vertical force F, runs in the groove of the record R and transfers it to the pickup C both desired vibrations, which correspond to the recorded useful signal, as well as undesirable vibrations, the z. B. caused by an uneven surface of the record, internal vibrations and the like and cause an undesirable lower resonance to occur in the subacoustic region. These undesirable Vibrations are from the front part of the pickup arm 1 on its bearing in its rear part transferred, where they bring the resiliently mounted counterweight 42 of the dynamic vibration damper to vibrate gen. If the counterweight 42 by means of the adjustment screw be 7 and the helical compression spring 6 according to the Ska la 421 tuned to the number of vibrations of the lower resonance is, it vibrates in phase opposition to the front part of the pickup arm 1. As a result, the Amplitude of the vertically oscillating front part of the pickup arm 1 and thus also the undesired resonance maximum decreased. The vibrations of the counterweight 42 are in resonance by moving the regulating screw in the viscous liquid, e.g. B. in colored silicone oil 81, optimally damped, with optimal immersion of the screw 32 depending on the required amount for damping according to the scale 811 of the damping factor.

. I ₉ Q.

is placed either directly on the wall of the transparent container 8 or on the body of the counterweight 42 is provided. With the dynamic vibration damper, its vertical effect also works vertically resilient part of the pickup arm 1, whereby its effective weight is reduced. There is no resonance maximum in the horizontal direction; because the flat pickup arm 1 has in this direction has practically no compliance, which is found in practically all currently known tubular Shows pickup arms. Since the useful signal from the left and right channels, which are on the side walls of the groove below at an angle of 45 ° is a result of a vertical and horizontal component the resulting resonance maximum, which is measured in both channels on this flat pickup arm 1, is essential smaller; because it does not contain the usual horizontal component, while the vertical component is due Effect of the dynamic vibration damper, which acts in the vertical direction, is suppressed to the maximum.

Claims (27)

Expectations M.) Flat turntable pickup arm in the form of a Plate with openings for elements for a mechanical and electrical connection of the pickup arm with the cartridge with the turntable, characterized, that the flexible front longer part (L) and the shorter rear part (W) of the pickup arm (1) with a number of auxiliary elements (11) for fastening, possibly also for making working elements on the pickup arm (1) accessible and for influencing its mode of operation is provided, at least one of the two surfaces of the pickup arm (1) on its front Part (L) with electrically conductive connections (14) from the pickup (C) to openings (11c) for elements for electrical connection to the turntable is provided at least at the level of the lower surface of the pickup arm (1) are arranged. 2. pickup arm according to claim 1,
characterized, that the upper surface of the pickup arm (1) with at least one electrically conductive connection (14) from the pickup (C) to openings (11d) for elements for an electrical connection is provided with the turntable, this connection being the top surface 233- (S 101Q1) -TE of the pickup arm (1) protrudes. 3. Pickup arm according to claim 1 or 2, characterized in that the auxiliary element (11) is in the form of at least one opening is trained. 4. pickup arm according to claim 1 or 2, characterized in that the auxiliary element (11) is in the form of a cutout is trained. 5. pickup arm according to claim 1, characterized in that that the auxiliary elements (11) in the form of at least one opening and at least one cutout are formed. 6. pickup arm according to one of claims 1 to 5, characterized in that the end of the front longer part (L) of the pickup arm (1) has a bevel (12), the edge of which with a line, the centers of a pair of openings (11a) for connecting elements for attaching the pickup (C), is parallel. 7. Pickup arm according to one of claims 1 to 6, characterized in that that the front longer part (L) of the pickup arm (1) with an opening (11b) for a locking element of the pickup arm (1) is provided in its rest position. 8. Pickup arm according to one of claims 1 to 7, characterized in that that the shorter rear part (W) of the pickup arm (1) with at least one opening (11) to achieve an increased flexural flexibility of the rear part (W) of the pickup arm (1) in the vertical direction is provided. 9. Pickup arm according to one of claims 1 to 7, characterized in that that the shorter rear part (W) of the pickup arm (1) with at least one cutout (11) to achieve an increased flexural flexibility of the rear part (W) of the pickup arm (1) in the vertical direction is provided. 10. Pickup arm according to one of claims 1 to 9, characterized in that that the shorter rear part (W) of the pickup arm (1) with at least one opening (11) and with at least a cutout (11) for achieving increased flexural flexibility of the rear part (W) of the pickup arm (1) is provided in the vertical direction. 11. Pickup arm according to one of claims 1 to 10, characterized, that the rear shorter part (W) of the pickup arm (1) in the longitudinal direction with a toothing (111, 111 ') is provided. 12. Pickup arm according to one of claims 1 to 11, characterized, that at least one surface of the front longer part (L) of the pickup arm (1) with electrically conductive Connections (14) from the pickup (C) to openings (11d) for elements for an electrical connection with the turntable at least partially with one electrically conductive coating (13) is provided. 13. Pickup arm according to one of claims 1 to 12, characterized in that that the conductive coating (13) and the conductive connections (14) from the pickup (C) to openings (11d) are formed from foils for an electrically conductive connection with the turntable. 14. Pickup arm according to one of claims 1 to 13, characterized, that the electrically conductive connections (14) from the pickup (C) to openings (11d) for elements for a electrically conductive connection with the turntable in the body of the pickup arm (1) are carried out. 15. Pickup arm according to one of claims 1 to 14, characterized in that that at least one surface of the front longer part (L) of the pickup arm (1) at least partially with an insulating film (13) with a conductive coating with conductive connections (14) from the pickup (C) to openings (11d) for elements for an electrical connection with the turntable is provided. 16. Pickup arm according to one of claims 1 to 7 and 11 to 15, characterized, that the rear part (W) of the pickup arm (1) with at least one stiffening element (5) to increase the stiffness of the adjacent part of the pickup arm (1) is provided in the vertical direction. 17. Pickup arm according to one of claims 1 to 16, characterized, that the pickup arm (1) is formed from a flat insulating plate. 18. Pickup arm according to one of claims 1 to 16, characterized in that that the pickup arm (1) is formed from a flat metal plate. 19. Pickup arm according to one of claims 1 to 16, characterized in that that the pickup arm (1) is formed from at least one metal plate with at least one layer is made of insulating material. 20. Pickup arm according to one of claims 1 to 7 and 11 to 19, characterized, that on the shorter rear part (W) of the pickup arm (1) an element (3) for adjusting the vertical force (F) on the needle tip of the turntable cartridge (C) is arranged, the pinion (31) meshes with a toothing (111, 111 '), with the movable and rotatable element (3) for adjusting the vertical force on the needle tip of the pickup (C) a counterweight system (4) is rotatably connected, a part of which extends laterally against at least one stiffening element (5) on the lower side of the pickup arm (1). 21. Pickup arm according to claim 20,
characterized, that part of the counterweight system (4) in the form of a dynamic vibration damper by a carrier (41) is formed with the sliding and rotatable element (3) for adjusting the vertical force on the The needle tip of the turntable cartridge (C) is connected to the upper horizontal part of the support (41) against the at least one stiffening and / or guide element (5) on the lower side of the pickup arm (1) supports a vertical part of the beam (41) with a bearing (411) for a swinging Arm (412) is provided on which the actual body of the counterweight (42) is fixed, and the free part of the swinging arm (412) by a helical Compression spring (6) is supported, the other end of which is attached to a lower fixed part of the beam (41) is. 22. Pickup arm according to claim 21,
characterized, that on the swinging arm (412) a tuning screw (7) is arranged, which engages from above in turns of the helical compression spring (6), the slope and the diameter of this compression spring (6) connected by the weight of the oscillating arm (412) Body of the counterweight (42) loaded condition of the slope and the diameter of the tuning screw (7) correspond. 23. Pickup arm according to claim 20 or 21, characterized in that that the body of the counterweight (42) connected to the swing arm (412) is close to the the side lying on the helical compression spring (6) with a scale (421) for setting the number of resonance vibrations is provided. _ * 7 24. Pickup arm according to one of claims 20 to 23, characterized in that that a transparent container (8) with a damping medium (81) is attached to the oscillating arm (412), Above which a regulating screw (32) is provided for adjusting the damping factor, which in the transparent Container (8) with the damping medium (81) through a passage opening in the oscillating arm (412) which regulating screw (32) is firmly connected to the non-vibrating part of the counterweight system (4) is. 25. Pickup arm according to one of claims 20 to 24, characterized in that that the inner wall of the through opening in the vibrating Arm (412) for the regulating screw (32) extended downwards into the interior of the transparent container (8) in this way is that between this inner wall and the wall of the transparent container (8) a collecting space for the damping medium (81) is formed, the content of which is greater than the volume of the damping medium (81) in the transparent container (8) is. 26. Pickup arm according to one of claims 20 to 25, characterized, that the body of the counterweight (42) attached to the oscillating arm (412) is attached to that of the transparent container (8) with the side facing the damping medium (81) with a scale for setting the damping factor is provided. 27. Pickup arm according to one of claims 20 to 25, characterized in that :- 8th that the transparent container (8) with the damping medium (81) on its side wall with a scale (811) is provided for setting the damping factor.