JPS5883301A - Suction device for record disk - Google Patents

Abstract

PURPOSE:To suck and release a record disk speedily and to obtain a playback sound with fidelity while correcting the curvature of the record disk by forming air holes of end parts of two annular seals for forming an airtight part between the record disk and a turntable. CONSTITUTION:An outer seal 9 and an inner seal 10 hold a record disk 23 and a discoid body 2 airtight. When a vacuum pump is connected to a check valve 13 by closing an opening-closing valve, an air chamber 3 is decompressed and the air part between the record disk 23 and discoid body 2 is also decompressed through the longitudinal groove of the inner seal 10. At this time, the air of the gap part 26 on the outer seal side 9 is sucked speedily through air holes 2, so the record disk 23 is sucked rapidly. The disk is fixed suctionally so that even if it is curved, the curvature is corrected, so a playback sound with fidelity is obtained while cross modulation due to the curvature of the disk is prevented. When the disk is released, air is supplied from the air holes 27 through the longitudinal groove of the inner seal 10 speedily, so the sucked state is released in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a record adsorption device 5 that is capable of firmly adsorbing a record to be played and placed on the turntable of a record playback device. .

It is well known that cross-modulation distortion occurs due to the warping of a record, and that ripple noise is generated when minute vibrations are induced in the record due to sound pressure, etc., from a speaker's side radiation. It is being

In order to solve this problem, the applicant of the present invention previously proposed a device for fixing a record by the suction action of negative pressure (see Japanese Patent Application No. 56-806J5). Briefly explaining this device, it has a disc body that is removably interposed between a record to be played and a turntable, and the pressure inside the disc body is reduced by a vacuum pump or the like. An air chamber is provided. On the other hand, on the surface side of this disk body, there is an annular outer layer that is in close contact with the outer circumferential edge (group guard) of the record and the inner circumferential edge near the label section, forming an airtight space between them. A seal and an inner seal are provided. This space and the air chamber are communicated with each other via an air intake port, and by reducing the pressure in the air chamber with a vacuum pump or the like, the record placed on the disc body is moved around the circle. It is firmly adsorbed and fixed onto the plate.

According to actual measurements, the adsorption force is quite strong, about 250:9, and as a result, the record is fixed almost integrally on the disc body with the warp corrected. In order to release the record from the disc body, the release valve is opened to open the air chamber to the atmosphere, but this kind of adsorption or release of the record can be done quickly and smoothly. In order to do this, it is necessary to quickly suck in and release the air especially from the attachment base end portions of the outer seal and inner seal. For this reason, in the conventional device, a ventilation groove is formed on the surface of the disc body in connection with the air intake port communicating with the air, and extends in the radial direction from the air intake port to quickly drain the air from the mounting base end of each seal. Like sucking and releasing? It's straining.

However, with this, when the record is picked up, the record may be damaged by the cracks in the ventilation groove, and the record may be deformed due to the ventilation groove itself, which may affect the sound quality and handling. It wasn't clever in that sense.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a record disc suction device that can quickly and smoothly attract and release a record disc without the above-mentioned drawbacks.

The present invention will now be described in detail with reference to embodiments shown in the accompanying drawings.

Referring to FIG. 1 and FIG. 2, this record disc suction device 1 has approximately the same diameter as the turntable of the record playback device, and is configured so that it can be detachably placed on it. There is. That is, this device 1 consists of a disk body 2 formed in a donut shape, and a pot that is assembled from above and below a central opening l of this disk body 2 to form an airtight air chamber 3 therein. It is composed of a pair of center plates 4 and a center frame 5. In this embodiment, the disc body 2 is made by cutting a solid aluminum plate, and a first
an annular groove 6, a spacer ring 7 integrally machined on the inner wall of the central opening, and a second annular groove 8 formed between the spacer ring 7 and the inner wall of the opening.
It is equipped with

An annular outer seal 9 is installed in the first annular groove 6, and a similarly annular inner seal 10 is installed in the second annular groove 8. The disc body 2 also has a pair of through holes 12 bored through its outer peripheral end wall toward the air chamber 3 from opposite directions. , 12b are formed, in which case a check valve 13 connected to a vacuum pump (not shown) is installed in one of the through holes 12a, and an air chamber 3 is installed in the other through hole 12b. An on-off valve 14 that is open to the atmosphere is installed. Note that the spacer ring 7 is also provided with a pair of communication holes 15.15 coaxially bored with the through holes 12a, 1'2b. The center slate 4 and the center frame 5 are composed of disks having the same diameter and are formed so as to be able to sandwich the spacer ring 7 from above and below. Center hole 1 into which the center spindle 19 of the turntable is inserted, as shown by the imaginary line in the figure.
Shaft cylinders 18 and 19 for forming the shaft 7 are provided. In this embodiment, the lower end of one barrel 18 is enlarged in diameter so as to tightly cover the other barrel 19. A plurality of columns 20 are erected on the outer periphery of the center frame 5, and by fixing the center plate 4 to these columns 20, the center plate 4 and the center frame 5 are connected to the spacer link 7. It is firmly fixed to the disc body 2 by sandwiching it, and has an air chamber 3 inside it.
will be formed. In this case, in order to improve the airtightness of the air chamber 3, the joint surface of each shaft cylinder 18, 19 and the spacer link 7 of the center plays 1 and 4 and the center frame 5 are
Grease or the like is attached to the joint surface.

The outer seal 9 is made of a flexible material such as neoprene rubber, and is formed to be forcefully fitted into the first annular groove 6 of the disc body 2, as shown in detail in FIG. A thin flange 22 is formed to extend outward from the base end 21 at a slight upward angle. In this case, the outer peripheral edge of the flange 22 is normally located above the upper surface of the disc body 2, and is in close contact with the outer peripheral edge, including the group guard 24, of the record 23 placed on this device. It looks like this. Further, the base end portion 21 is fitted into the first annular groove 6 so as to be located below the surface of the disc body 2, thereby making a connection between the side wall 25 of the first annular groove 6 and the outer seal 9. A predetermined gap portion 26 is formed between them.

In connection with this, in the present invention, a ventilation hole 27 is provided extending from the side wall 25 toward the through hole 12b, and the void portion 26 communicates with the through hole 12b through the ventilation hole 27. It is configured as follows. In this embodiment, a ventilation hole 27 is similarly provided on the side of the through hole 12a. The inner seal 10 is also made of a flexible material such as neoprene rubber, like the outer seal 9 described above. As shown in FIG. 4, this inner seal 10 includes a base end 28 formed to be forcibly inserted into the second annular groove 8 of the disc body 2, and a base end 28 formed to be forcibly inserted into the second annular groove 8 of the disc body 2. The flange 29 is formed to extend inward from the portion 28 at a slight upward angle. In this case, one inner circumferential end of the flange 29 is normally located above the top surface of the disc body 2, similar to the previously mentioned flange 22, and is a non-recording surface adjacent to the label portion of the record disc 23. It is designed to be in close contact with the The inner seal 10 also includes a plurality of vertical grooves 30 that communicate with the air chamber 3 formed in the outer circumferential wall of the base end portion 28 .

The proximal end portion 28 is installed in the second annular groove 8 so as to leave a predetermined space between it and the bottom of the groove, and there is a pullout on the inner wall of the second annular groove 8 which is held down by the outer peripheral end of the center plate 4. A rib 31 for stopping is provided.

The check valve 13 and the on-off valve 14 have the same structure as that explained in Japanese Patent Application No. 80645, which was previously proposed by the present applicant, and will not be described in detail here, but the outline is as follows. be. That is, as shown in FIG. 5, the check valve 13 includes a cylinder 33 that is airtightly inserted into the through hole 12a, and a gate-shaped frame (not shown) connected to the cylinder 33. It includes a valve body 35 held by a continuous holding ring 34. The valve body 35 consists of a bottomed cylindrical body made of a flexible material such as neoprene rubber and has an outer diameter substantially larger than the inner diameter of the cylinder 33, and its bottom side is mounted within the retaining ring 34 and the other opening The side peripheral wall is inserted into the cylinder 33 in an airtight manner. Therefore, when a hose extending from a vacuum pump is connected to the cylinder 33 and air is sucked, the valve body 35 is deformed so as to collapse inward due to the negative pressure. Then, when the hose is removed and the cylinder 33 is opened to the atmosphere, the air pressure difference causes the cylinder 33 to return to its normal state and close the cylinder 33. On the other hand, as shown in FIG.
8, and a cap 40 made of a flexible material such as neoprene rubber and rotatably placed on the head side of the cylinder 38.
It is equipped with

In this case, a through hole 39 that opens toward the inside of the cylinder is formed in the circumferential wall on the head side of the cylinder 38, and on the other hand, the cap 40 selectively opens and closes the through hole 39 by rotating the cap 40. An opening 41 is provided.

Next, the operation of this invention will be explained. Prior to the start of record performance, this record disc suction device 1 is set on the turntable of a record reproducing device. In this case, the length of the center spindle 16 of the turntable is
The thickness of this device is approximately 95 mm.
Since the center spindle 16 passes through the center hole 17 and protrudes above it by about 5.5 inches.

When the record disc 23 is placed on the disc body 2 using the center spindle 16 as a guide, the space between the record disc r23 and the disc body 2 is airtightly sealed by the outer seal 9 and the inner seal 10.

Next, rotate the cap 40 and insert the opening 41 into the through hole 3.
9, the on-off valve 14 is closed, and a hose from a vacuum pump (not shown) is connected to the cylinder 33 of the check valve 13 to operate the vacuum pump. As a result, the valve body 35 of the check valve 13 is deformed so as to be crushed inward, and the air in the air chamber 3 is depressurized through the through hole 12 a and the communication hole 15 . Air in the space between the record 23 and the disk body 2 is also sucked in through the vertical groove 30, but in this case, in this invention, the air in the gap 26 on the outer seal 9 side is not penetrated. The air is quickly sucked in through the ventilation holes 27 and 27 communicating with the holes 12a and 12b, so that the record 23 is quickly and firmly placed on the disc body 2.
It can be fixed by suction.

After that, when the hose is removed from the check valve 13, the valve body 3
5 performs a valve closing operation to reliably close the through hole 12a. In this way, the inside of the device 1 is maintained at a negative pressure state. In this case, even if a small amount of air flows in from each seal part, the air chamber 3 acts as a negative pressure accumulator with a large volume. Because of this, the record disc 23 can be suctioned and fixed for a long time. and,
By rotating the turntable, this device 1 rotates steadily together with the turntable without slipping, lowers the needle of the pickup cartridge onto the record 23, and enters the playing state. At this time, record 2
3 is firmly suctioned and fixed on the disc body 2 so that the warpage is corrected, so that cross modulation distortion due to the warp of the reflex disc 23 and ripple noise due to secondary radiation sound pressure from the speaker, etc. It is possible to obtain high-fidelity playback sound without the occurrence of

To remove the record 23 at the end of the performance, etc.
The cap 40 is rotated to align the opening 41 with the through hole 39 and open the on-off valve 14. As a result, air is sucked into the air chamber 3 through the through hole 12b and the communication hole 15, and between the record 23 and the disc body 2 through the vertical groove 30 and the above-mentioned ventilation hole 27 in the present invention. Air is quickly introduced into the tank, and the adsorption state caused by the negative pressure described above is released in a short time.

In addition, in the above embodiment, the base end portion 21 of the outer seal 9
A gap portion 26 is formed by providing a step between the outer seal 9 and the disc body 2, and as shown in FIGS. It is also possible to provide longitudinal grooves 42 in the grooves and provide a gap therebetween. (Although the ventilation holes 27 are arranged in relation to the through holes 12a and 12b so as to extend toward them, the present invention is not limited to this arrangement or the number of ventilation holes 27. In some cases, the first annular groove 6 may be bored directly from other parts of the side wall 25 toward the first annular groove 8, and in this way, the inner seal 10 part and the outer seal 9 part can be bored. may be communicated with each other.

As is clear from the description of the embodiments described above, according to the present invention, it can be easily set on an existing turntable in a detachable manner, and even in the case of a record with a warp, the warp can be corrected. A record adsorption device that can firmly adsorb and fix a record disc can be obtained. In this device, ventilation holes are drilled in the disk body to allow communication between the base ends of the inner seal and outer seal, allowing for quick and smooth adsorption and release of records. It can be carried out as well as in the conventional manner (
Compared to a method in which ventilation grooves are provided on the surface of the disk body, there is no need for deburring work, which is also required to form the ventilation grooves, and the surface of the disk body can be finished extremely smooth. , you will be able to obtain higher fidelity playback sound.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a record disc suction device according to the present invention.
FIG. 2 is a sectional view taken along line n-n in FIG. 1, FIGS. 3 to 5 are enlarged sectional views showing main parts of the present invention, and FIG. A partial sectional view, and FIG. 7 is a plan view thereof. In the figure, ■ is a record adsorption device, 2 is a disc body, 3 is an air chamber, 6 is a first annular groove, 8 is a second annular groove, 9 is an outer seal, 1o is an inner seal, 12a, 12b 13 is a through hole, 13 is a check valve, 14 is an on-off valve, 16 is a center spindle, 23 is a record disc, 25 is a side wall, 426 is a gap, and 27 is a ventilation hole. Patent applicant: Takuya Ohara, patent attorney representing Audio-Technica Co., Ltd. Procedural amendment (method) May 7, 1980, 1982 Patent M No. 182106 2, title of invention: Record adsorption device 3, amendment Person 4, Agent 〒102 5, Date of amendment order April 9, 1980 (shipment date: April 27 of the same year) 0
Written amendment (spontaneous) May 7, 1980 1. Indication of the case 1982 Patent Application No. 182106 2. Title of invention ``Record adsorption device 3'' Patent application related to the amended person's case Person 4, Agent 〒102 5, Date of amendment order (voluntary)

Claims (1)

[Scope of Claims] (+1) A record adsorption device that is detachably interposed between the turntable of a record playback device and the record being played, and rotates together with the turntable while holding the record by suction. The turntable includes a disc body having a center hole through which the center spindle of the turntable is inserted, and the disc body has an airtight airtight air hole formed around the center hole in the center of the disc body. a chamber, a through hole passing through the disk body, one end of which is opened at its outer peripheral end wall, and the other end of which is opened to the air chamber; a through hole is fitted with a guard, and is used for a vacuum pump or the like; a valve device capable of selectively communicating the air chamber with a negative pressure source and opening the air chamber to the atmosphere; an outer annular groove and an inner annular groove formed concentrically; an annular outer seal and an inner seal disposed in each of these annular grooves to form an airtight space between the record disc; a first air passage formed in the inner annular groove so as to open from the air chamber toward the space along the base end of the inner seal; and a side wall of the outer annular groove included in the space. A record adsorption device characterized in that a second air passage consisting of a ventilation hole is provided from a portion of the disk body through the inside thereof to communicate with the air chamber. (2) . The record adsorption device according to claim (1), wherein the ventilation hole communicates with the air chamber via the through hole.