JPS5845081B2 - Turntable manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a turntable, and is particularly characterized by a method for forming strobe stripes.

In order to determine the rotational speed of a turntable of a record player, a strobe device is known in which strobe stripes are provided directly on the turntable and the stripes are irradiated with light from a strobe light source.

Figure 1 shows such a strobe device, in which strobe stripes 2 are provided on the bottom surface of a turntable 1 according to the frequency and the number of revolutions of the record, and light from a strobe light source 3 is irradiated onto the stripes. By looking into a mirror 5 through a see-through window 4, strobe stripes are observed.

In this case, it is of course necessary to accurately define the interval between the strobe stripes at a predetermined interval, but it is also necessary to arrange the strobe stripes on the same circumference around the rotation axis 6 of the turntable. .

When actually manufacturing a turntable, the applicant believes that the use of a strobe device is difficult because the strobe stripes are not aligned on a constant circumference around the rotation axis 6 of the turntable, rather than because the strobe stripes are unevenly spaced. In view of the fact that the strobe stripes are often aligned on a constant circumference centered on the rotation axis of the turntable, it is an object of the present invention to provide a turntable in which strobe stripes are accurately aligned on a constant circumference centered on the rotation axis of the turntable.

FIG. 2 shows the strobe stripes of a conventional turntable.

The method for forming it is to first paint the turntable 1 molded in a turntable mold with a color that does not reflect light, such as black, and then cut it with a diamond band to cover the entire surface of the dotted convex parts. The strobe stripe 2 was formed by finishing it in a reflective mirror shape.

However, when the dot-like protrusions are integrally molded with the turntable, it is difficult to mold the protrusions so that they are accurately aligned on a constant circumference around the rotation axis of the turntable.

In other words, ■It is difficult to obtain sufficient precision of the mold■
During molding, sink marks (a type of depression) and warpage occur near the convex part for the strobe, making it impossible to position the convex part correctly.■
If the rotation axis of the turntable is not centered correctly, even if the strobe protrusions are arranged on the same circumference, the center of the circle of the strobe protrusions and the center of the turntable's rotation axis may be misaligned when turning. It is difficult to accurately set the strobe stripes because of the eccentricity of the strobe stripes with respect to the rotation axis of the chiffle.

According to the present invention, the protrusions 7 for strobe stripes are formed to be slightly wider in the radial direction of the turntable.

Then, grip the outer periphery of the turntable 1 and rotate it, make a hole in the turntable by applying a drill, fit the shaft into the hole, form a rotating shaft 6, and turn around the rotating shaft. While rotating the table, a cutting tool (not shown) having a width a narrower than the above-mentioned width is brought into contact with the convex portion 7, and the paint on the surface of the convex portion is peeled off by the width a, thereby creating strobe stripes 2. form.

Of course, the result is the same even if the turntable is fixed and the cutting tool is rotated.

If formed in this way, the strobe stripes will be precisely aligned on a constant circumference centered on the rotation axis of the turntable,
The occurrence of defective products can be significantly reduced.

As described above, the present invention involves molding a turntable having convex portions for strobe stripes on the bottom surface spaced apart by a predetermined distance in the circumferential direction, and applying anti-reflection coating to the turntable. The strobe stripes were formed by applying a cutting tool to the top surface of the convex part and performing the only cutting process, and removing the paint from the center, leaving both ends of the convex part intact. Strobe stripes can be formed by cutting.

■Since the strobe stripes are accurately aligned on a constant circumference centered on the rotation axis of the turntable, the occurrence of defective products can be reduced.

■The strobe stripes are on the bottom of the turntable, and when using the strobe device, the cut parts cannot be seen directly, so it looks good.

You can expect this effect.

Additionally, in the past, a protrusion having a constant width was first formed by applying a tool such as a cutting tool to both ends of the protrusion for strobe stripes integrally molded on the turntable surface. Then, an anti-reflection coating is applied to the turntable having such a convex portion, and then the entire surface of the convex portion that has been painted is cut again to form strobe stripes. However, in such conventional methods, there is a possibility that the center of rotation during the first cutting process and the center of rotation during the second cutting process may be misaligned. However, in the present invention, such inconvenience does not occur because cutting is performed only once.

In addition, the place where the cutting process is performed and the place where the painting process is performed are usually far apart, and inserting the painting process between two cutting processes increases the distance the product must travel. However, the manufacturing method of the present invention does not have such inconvenience.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the strobe device, Figure 2 is a diagram showing the back side of a conventional strobe striped turntable, and Figure 3 is a diagram for explaining the strobe device.
The figure is a diagram showing the back side of a strobe striped turntable manufactured by the method according to the present invention. Explanation of main drawing numbers, 1...Turntable, T.
...Protrusion, 6...Rotation axis, 2...
- Strobe stripes.

Claims (1)

[Claims] 1. A step of molding a turntable having protrusions on the bottom surface that form strobe stripes arranged at predetermined intervals on substantially the same circumference, a step of applying anti-reflection coating to the bottom surface of the turntable, and a step of forming the turntable. While rotating the cutting tool relatively, apply a cutting tool with a smaller diameter to the upper surface of the protrusion and cut it, leaving both ends of the protrusion intact and painting the central part. A method for manufacturing a turntable comprising the step of forming strobe stripes arranged on the same circumference around the turntable rotation axis by peeling off the turntable.