JPS596495Y2 - Arm base plate for record player - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an arm base plate for a record player, and more particularly to an arm base for a record player that is rigid, has a large internal loss, and can prevent excitation by elastic waves.

Among the conventionally known arm base plates for record players, there is an aluminum die-cast plate which has relatively high rigidity and can prevent excitation by elastic waves.

However, even with an arm base plate made of die-cast aluminum, it does not have the ideal rigidity as an arm base plate,
The reality is that internal loss and excitation prevention characteristics are not achieved.
Since the internal loss of the metal part is smaller than the ideal value, it is necessary to install a plastic plate to form a double structure, and furthermore, the cost is relatively high.

In order to improve this drawback, various new materials suitable for arm base plates have been proposed in the past, but it is technically difficult to mix metal powder or mineral substances into plastic materials in large quantities in arbitrary amounts. Therefore, the problem remains that it is difficult to obtain materials with sufficiently large internal loss or sufficiently low resonant frequency.

Therefore, this idea aims to improve the drawbacks of the arm base plate used in conventional record players and make it ideal by using new materials. We succeeded in making the base plate have a large internal loss and a low resonant frequency.

The material constituting this arm base plate can be made by freely mixing any amount of mineral substances, such as metal materials, with plastic, and can fully satisfy the required characteristics.

The arm base plate, which is a structural member of a record player, supports the tone arm unit, so it has high rigidity, can sufficiently absorb internal and external vibrations, and has a large so-called internal loss. Specific gravity, low resonant frequency, and less affected by elastic waves;
The material is required to have excellent workability.

The material itself that makes up the arm base plate of this invention uses thermoplastic resin to improve impact resistance and shapeability, and it also uses fine particles to increase specific gravity and rigidity. Sulfate is selected as the base material for reasons such as the smooth surface of the barrel or shaped product, and this base material is bonded with the resin described above, thereby creating an ideal arm base plate. It is.

Powders of precipitated sulfates such as barium sulfate, lead sulfate, calcium sulfate, etc. have suitably large specific gravity;
The granules are used as a base material, and the weight ratio is approximately 30 as a binder for this base material.
% or less of a composite resin such as a thermoplastic resin, and the resulting mixture is formed into a desired shape by compressing it or by a molding method such as injection.

Synthetic resins such as thermoplastics and thermosetting resins have the function of binding sulfate particles, albeit indirectly, and are so-called binders for sulfate particles, such as polyethylene, polypropylene, vinyl chloride resin, etc. Use.

The thermoplastic resin used as the bonding material may be a thermosetting resin, but it requires more steps during shaping than the thermoplastic resin.

Furthermore, in addition to the base material and the binder, a coupling agent is used to strengthen the bond between the base material and the binder.

Next, a blending example of sulfate and thermoplastic resin will be shown.

Mixing example 1 (weight ratio) Barium sulfate 75% Polyethylene 23% Plasticity (viscosity reducing agent) 1.4% Antioxidant 0.5% Coupling agent 0.1% Mixing example 2 (weight ratio) Barium sulfate 80% glass Fiber strength polypropylene 18.0% plasticizer (viscosity reducing agent) 1
．． 4% Antioxidant 0.5% Coupling agent 0.1% Formulation example 3 (weight ratio) Barium sulfate (trade name Baride) 95% Polypropylene 3% Plasticizer (viscosity reducing agent) 1.4% Antioxidant 0 .5% Coupling agent 0.1% In addition, formulation examples 1, 2. In step 3, it is preferable to add glass fiber or carbon fiber to improve the mechanical strength of the precept-shaped article.

The above formulation examples 1 and 2. In No. 3, the coupling agent is used to further strengthen the bond between polyethylene and barium sulfate.

In addition, the specific gravity of barium sulfate as a sulfate is 4.0~
4.5, and in order to further increase this specific gravity, a metal oxide such as titanium iron (trade name Illuminite, specific gravity 4.5 to 5.0) is added to create an arm base plate for record players. Improve the properties by adjusting the specific gravity (weight) as required.

A blending example in this case is as follows.

Barium sulfate (trade name Barite) 60% Metal oxide (titanium iron trade name Illuminite) 25% Polypropylene 13% Plasticizer (viscosity reducing agent) 1.4% Antioxidant 1.5% Cutting agent 0.1% In addition to titanium iron, metal oxides include ferrite, lead oxide, ferroalloy, ferrosilicon, and other metal oxides, and it is also possible to substitute other metals.

Typical combination examples have been shown above, and the actual shape of an arm base plate for a record player using these examples will be explained.

■ Barium sulfate and other substances other than the coupling agent, specifically polyethylene, plasticizer, and antioxidant, are kneaded.

III Separately from I, barium sulfate and a coupling agent are kneaded.

III The kneaded materials of I and II are further kneaded.

The mixed material obtained in step IV III is kneaded using an extruder until it becomes fluid, and the material obtained in this step is pressurized and shaped into a desired shape.

That is, the arm base plate 1 has a shape as shown in the cross-sectional view in the attached drawing, and has an arm bearing part 2 erected thereon, the lower end is fixed with a nut 3, and a tone arm pipe 4 is supported on this bearing part 2. has been done.

A cartridge 5 is attached to one end of the tone arm pipe 4, and a counterweight 6 is attached to the other end.

Therefore, when external vibration is transmitted to the arm base plate 1,
The vibration propagates from the arm base plate 1 to the arm bearing 2, tone arm pipe 4, and cartridge 5, causing problems such as howling and deterioration of sound quality, but the arm base plate 1 itself has a large internal loss. This prevents deterioration of sound quality and reduction of S/N ratio.

As is clear from the above explanation, the record player arm base plate of this invention has a large internal loss, can reliably prevent abnormal vibrations caused by elastic waves, and has excellent shapeability, making it ideal for complex shapes. However, it is easy to form and suitable for mass production.

[Brief explanation of drawings]

The accompanying drawing is a schematic sectional view showing the main parts of a record player using the arm base plate according to this invention. 1...Arm base plate, 2...Arm bearing part, 4...Tone arm pipe, 5...
····cartridge.

Claims (1)

[Scope of utility model registration request] An arm base plate for a record player, which is formed by adding a binder such as resin to a base material of sulfate, such as barium sulfate, for the purpose of increasing specific gravity, and adding a binder such as resin for the purpose of binding base material particles.