JPS6230183Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an improved structure of a playback stylus applied to video discs, etc., and requires less processing than conventional ones, and is therefore suitable for mass production and contributes to lower prices. We try to provide what we can.

FIG. 1 schematically shows the structure of a playback needle applied to a conventional capacitive video disc player. This starts with a quadrilateral prismatic needle made of sapphire, the lower four corners of which are cut off, and the part that contacts the recording medium is processed into a flat surface. Therefore, the lower part of the needle material 1 has a total of five machined surfaces 2, 3, 4, 5,
You will have 6. Note that 7 is an electrode formed on one side of the needle material, the total width 8 of this electrode is defined by the machined surfaces 2 and 3, and the sliding distance 9 of this needle material in the track direction is defined by the machined surfaces 4 and 5. stipulated. As described above, conventional recycled needles require processing at least five times on the ready-made prismatic needle material that is the starting material, making them expensive.

The present invention has been made in view of the above-mentioned points, and is intended to provide an inexpensive recycled needle that requires fewer processing steps than conventional needles.

FIG. 2 shows one embodiment of the present invention, and the present invention will be explained below based on this. Reference numeral 10 denotes a prismatic needle made of diamond or sapphire, with a first machined surface 12 formed at the lower part thereof so as to be inclined with respect to the longitudinal direction 11 of the needle, and a part adjacent to the first machined surface. second and third processed surfaces 13 formed to form electrode forming surfaces within the first processed surface;
14, and a fourth processed surface 15 formed at the lower end of the needle material 10 so as to be adjacent to each of the processed surfaces 12, 13, and 14 and to form a sliding surface for the recording medium.
I am trying to prepare for this.

16 is an electrode. Such a regenerated needle may be molded according to the procedure shown in FIG. First, mark A, B, C, and D on the lower part of the ready-made rectangular prism-shaped needle material 20.
Grinding is performed so that a slope 21 defined by (FIG. 3A) appears, and then an electrode layer 22 is formed on this slope (FIG. 3B). Next, the slopes 2 forming the slope 21 are
From the two vertices B and D, respectively, the slope, that is, the electrode layer 2
the second and third electrodes to form a predetermined electrode width on the second electrode.
After processing, the broken line parts 23, 2 shown in Fig. 4 (b)
Remove up to 3. Thereafter, the lower end of the needle material 20 is machined so as to have a predetermined sliding contact distance 9, and the machined surface (fourth machined surface 15) is approximately perpendicular to the first machined surface 12, as shown in FIG. constitutes a regenerated needle.

In the present invention, the first processed surface, which becomes the electrode surface, is one of the needle materials.
It is formed at an angle with two ridgelines chamfered. Therefore, the amount of processing required for the second and third processed surfaces formed on both sides to specify this electrode surface is relatively small. In contrast, in the prior art (for example, Japanese Patent Laid-Open No. 53-90917), the ridgeline of the needle material is not chamfered in advance. Therefore, the amount of machining on both sides of the electrode surface must become large. Moreover, since the structure is such that the electrode surface is formed after forming the processed surfaces on both sides,
Excessive machining of this surface directly affects the electrode width, making it difficult to set the electrode width.

As mentioned above, the recycled needle of the present invention uses an existing prismatic needle material as a starting material and is formed into a predetermined shape by processing four sides, so it is easier to process than the conventional five-sided process. Needles can be formed with less man-hours, and inexpensive recycled needles can be provided. In addition, the side surface of this scanning needle on the track entry side on the recording medium is symmetrical with respect to the track center line and is divided by one ridgeline of the prismatic needle material, so that dust and the like on the recording medium do not adhere to the scanning needle. It is possible to prevent tracking errors due to adhesion of dust, etc.

[Brief explanation of the drawing]

FIG. 1 shows a conventional regenerated needle, in which A is a front view and B is a side view. Figure 2 is part 1 of this invention.
An example is shown in which Figure A is a perspective view and Figure B is a side view. Figures 3A and 3B are diagrams explaining the manufacturing method; Figure 3A is a diagram explaining the process of forming the first processed surface, and Figure 3B is a diagram explaining the process of forming the electrode and forming the second and third processing surfaces. . Explanation of main symbols, 10, 20...Needle material, 12...
...First processed surface, 13, 14... Second and third processed surfaces, 15... Fourth processed surface.

Claims (1)

[Scope of utility model registration request] A first machined surface formed on the lower part of a prismatic needle material made of sapphire or diamond so as to be inclined with respect to the longitudinal direction of the needle material and chamfer one ridgeline, and a first machined surface adjacent to the first machined surface. a second and third machined surface formed to constitute an electrode forming surface within the first machined surface; a fourth molded to form a sliding surface against the medium;
A recycled needle structure comprising a processed surface.