CA1145267A - Disc - Google Patents
DiscInfo
- Publication number
- CA1145267A CA1145267A CA000372129A CA372129A CA1145267A CA 1145267 A CA1145267 A CA 1145267A CA 000372129 A CA000372129 A CA 000372129A CA 372129 A CA372129 A CA 372129A CA 1145267 A CA1145267 A CA 1145267A
- Authority
- CA
- Canada
- Prior art keywords
- annular recess
- record
- outer annular
- mat
- recess
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
- G11B19/2009—Turntables, hubs and motors for disk drives; Mounting of motors in the drive
- G11B19/2018—Incorporating means for passive damping of vibration, either in the turntable, motor or mounting
Abstract
ABSTRACT OF THE DISCLOSURE
A disc platter for supporting a record on a turntable platter which includes a core having a central aperture for slidable insertion of the spindle of the turntable and a planar top and bottom surface. Both the top and bottom surface each have an inner annular recess and an outer annular recess the respective inner and outer recesses being concentrically aligned. To the top inner annular recess and the bottom outer annular recess there is affixed a soft visco elastomeric material suitable for dampening microvibrations. The top inner annular mat is coextensive with the labelled portion of a record when the record is axially aligned with the turntable platter. To the bottom inner annular recess and the top outer annular recess there is affixed a hard nonreactive visco elastomeric material which dissipates and dampens vibrations. The combination of the foregoing mats and their positioning minimizes reflec-tions back to the record, resonances of the platter and other vibrations while providing a superior dynamic range of sound.
A disc platter for supporting a record on a turntable platter which includes a core having a central aperture for slidable insertion of the spindle of the turntable and a planar top and bottom surface. Both the top and bottom surface each have an inner annular recess and an outer annular recess the respective inner and outer recesses being concentrically aligned. To the top inner annular recess and the bottom outer annular recess there is affixed a soft visco elastomeric material suitable for dampening microvibrations. The top inner annular mat is coextensive with the labelled portion of a record when the record is axially aligned with the turntable platter. To the bottom inner annular recess and the top outer annular recess there is affixed a hard nonreactive visco elastomeric material which dissipates and dampens vibrations. The combination of the foregoing mats and their positioning minimizes reflec-tions back to the record, resonances of the platter and other vibrations while providing a superior dynamic range of sound.
Description
The present invention relates to a disc used to support a record on a turntable.
Records being generally thin and flexible re~uire support when played on a turntable. Various types of discs have been employed to provide the latter-mentioned support.
The major problem to be overcome by such discs is their tendency to undergo mechanical vibration in response to the stylus tracking the grooves of the record. Such vibration is the major source Gf distortion in a turntable system. In order to dampen and isolate these microvibrations some turntable have used a soft disc. A soft disc allows exces-sive movement to occur at the stylus point of contact but suppresses angular microvibrations in the record surface.
The increased deflection of the groove walls thus permitted results in a massive loss of information and dynamic range.
Moreover, most soft discs do not dissipate the energy which they absorb but rather reintroduce it back into the record with only a small decrease in amplitude and a large change in time constant. The latter reintroduction causes the sound to become blurred and indistinct.
Hard discs exhibit a superior dynamic range but also suf~er from an entirely different set of problems~
Angular and linear microvibrations in this case are reflec-ted by the disc back to the record causing resonances in the latter. Moreover, hard discs have a tendency to resonate when mechanically excited by the stylus tracking either therecord or the turntable platter. The sound from hard discs is usually characteristic of large reverberant halls com-plete with irregular and slow decay of airborne vibxations.
The discordant nature and exaggerated size of the sound --1-- .~
image in this case represents a large loss of information.
According to the invention there is provided adisc for supporting a record on a turntable platter. The disc is comprised of a core which includes a central aper-ture for slidably receiving a spindle of the turntableplatter. The bottom surface of the core is planar having a bottom inner annular recess for positioning concentrically with the labelled portion of a record and an outer annular recess for positioning concentrically with the grooved portion of a record. The core has a planar top surface with a top inner annular recess coextensive and concentric with the bottom inner annular recess and substantially parallel thereto. The top surface also has a top outer annular recess coextensive and concentric with the bottom outer annular recess. A top inner annular mat of soft visco elastomeric material suitable for dampening microvibrations is matingly received and bonded to the top inner recess of the core. A top outer annular mat is made of a nonreactive hard visco elastomeric material having particles which dissipate and dampen microvibrations. The latter particles are suspended in a resilient matrix which isolates the particles from one another. The latter mat is matingly received by and bonded to the top outer annular recess of the core. A bottom inner annular mat of the nonreactive material is matingly received by and bonded to the bottom inner recess. A bottom outer annular mat of the soft material is matingly received by and bonded to the bottom outer recess.
Preferably, the nonreactive material is an aggre-gation of cork and jute particles held in a matrix of 6~7 resilient material. The soft material may be nitrogen filled polyvinyl cast foam having a density of 20 pounds per cubic foot.
Advantageously, the core is a hard thermoplastic material which minimizes linear resonance or ringing and tends to restrict annular vibrations on the surface of the record.
To provide a level surface on a top groove portion of a record the top outer annular recess of the disc is tapered away from the bottom outer annular recess in a direction radially outwardly from the center of the core at an angle such that when the center of the record is pressed into contact with the upper inner annular mat, the bottom grooved surface of the record is in intimate contact with the upper outer annular mat and the upper grooved surface of the record is substantially flat.
A suitable angle of taper is such that the diffe-rence in thickness of the core between the outer extremity of the top and bottom outer annular recesses and the inner extremity thereof is 0.025 inches.
A suitable resilient material is neoprene sponge.
The aggregation of cork, jute, in a matrix of resilient material such as neoprene or rubber sponge is useful because of its nonresonance, its resistance to the conduction of microvlbrations and its excellent low mecha-nical impedance characteristics. The different particles in the material dissipate and dampen microvibrations and, by reason of being suspended in a resilient material cannot transfer such microvibrations from cork particle to cork particle. Thus, the aforesaid particles tend to disperse the coherent energy contained in such microvibrations.
The polyvinyl cast foam is a soft material having an extremely long time constant which isolates and dampens microvibrations originating from the spindle which excite the turntable platter. It sits much lower into the surface of the core because of the increase in profile around the label area of records.
The relative differences in the hardness of ~he various materials and the construction of the disc and their different mechanical impedances result in a structure which is stable and resistant to mechanical vibrations present in the turntable system.
In the drawings which present a preferred embodi-ment of the invention:
Figure 1 is a perspective view showing how the platter is used on a turntable system.
Figure 2 is a view in cross section of the disc.
In the following description words such as "outer", "inner", "top", and "bottom" are used in their relative sense only.
As shown in Figure 1 a disc 10 is positioned beneath a record 30 and a turntable platter 40 of a turn-table system (not shown). A clamping device 36 or a weight i5 fitted around the spindle 38 of the turntable system which turns with the platter 40 gripping the spindle and pressing down on the extremities of a labelled portion 34 of the record 30. The stylus then runs along the grooved portion 32 of the record to produce the sound. As seen in Figure 2 the disc 10 has a thermoplastic core 11 with a central aperture 12. The top surface of the core 11 has a ~s~
top inner annular recess 22 and a top outer annular recess
Records being generally thin and flexible re~uire support when played on a turntable. Various types of discs have been employed to provide the latter-mentioned support.
The major problem to be overcome by such discs is their tendency to undergo mechanical vibration in response to the stylus tracking the grooves of the record. Such vibration is the major source Gf distortion in a turntable system. In order to dampen and isolate these microvibrations some turntable have used a soft disc. A soft disc allows exces-sive movement to occur at the stylus point of contact but suppresses angular microvibrations in the record surface.
The increased deflection of the groove walls thus permitted results in a massive loss of information and dynamic range.
Moreover, most soft discs do not dissipate the energy which they absorb but rather reintroduce it back into the record with only a small decrease in amplitude and a large change in time constant. The latter reintroduction causes the sound to become blurred and indistinct.
Hard discs exhibit a superior dynamic range but also suf~er from an entirely different set of problems~
Angular and linear microvibrations in this case are reflec-ted by the disc back to the record causing resonances in the latter. Moreover, hard discs have a tendency to resonate when mechanically excited by the stylus tracking either therecord or the turntable platter. The sound from hard discs is usually characteristic of large reverberant halls com-plete with irregular and slow decay of airborne vibxations.
The discordant nature and exaggerated size of the sound --1-- .~
image in this case represents a large loss of information.
According to the invention there is provided adisc for supporting a record on a turntable platter. The disc is comprised of a core which includes a central aper-ture for slidably receiving a spindle of the turntableplatter. The bottom surface of the core is planar having a bottom inner annular recess for positioning concentrically with the labelled portion of a record and an outer annular recess for positioning concentrically with the grooved portion of a record. The core has a planar top surface with a top inner annular recess coextensive and concentric with the bottom inner annular recess and substantially parallel thereto. The top surface also has a top outer annular recess coextensive and concentric with the bottom outer annular recess. A top inner annular mat of soft visco elastomeric material suitable for dampening microvibrations is matingly received and bonded to the top inner recess of the core. A top outer annular mat is made of a nonreactive hard visco elastomeric material having particles which dissipate and dampen microvibrations. The latter particles are suspended in a resilient matrix which isolates the particles from one another. The latter mat is matingly received by and bonded to the top outer annular recess of the core. A bottom inner annular mat of the nonreactive material is matingly received by and bonded to the bottom inner recess. A bottom outer annular mat of the soft material is matingly received by and bonded to the bottom outer recess.
Preferably, the nonreactive material is an aggre-gation of cork and jute particles held in a matrix of 6~7 resilient material. The soft material may be nitrogen filled polyvinyl cast foam having a density of 20 pounds per cubic foot.
Advantageously, the core is a hard thermoplastic material which minimizes linear resonance or ringing and tends to restrict annular vibrations on the surface of the record.
To provide a level surface on a top groove portion of a record the top outer annular recess of the disc is tapered away from the bottom outer annular recess in a direction radially outwardly from the center of the core at an angle such that when the center of the record is pressed into contact with the upper inner annular mat, the bottom grooved surface of the record is in intimate contact with the upper outer annular mat and the upper grooved surface of the record is substantially flat.
A suitable angle of taper is such that the diffe-rence in thickness of the core between the outer extremity of the top and bottom outer annular recesses and the inner extremity thereof is 0.025 inches.
A suitable resilient material is neoprene sponge.
The aggregation of cork, jute, in a matrix of resilient material such as neoprene or rubber sponge is useful because of its nonresonance, its resistance to the conduction of microvlbrations and its excellent low mecha-nical impedance characteristics. The different particles in the material dissipate and dampen microvibrations and, by reason of being suspended in a resilient material cannot transfer such microvibrations from cork particle to cork particle. Thus, the aforesaid particles tend to disperse the coherent energy contained in such microvibrations.
The polyvinyl cast foam is a soft material having an extremely long time constant which isolates and dampens microvibrations originating from the spindle which excite the turntable platter. It sits much lower into the surface of the core because of the increase in profile around the label area of records.
The relative differences in the hardness of ~he various materials and the construction of the disc and their different mechanical impedances result in a structure which is stable and resistant to mechanical vibrations present in the turntable system.
In the drawings which present a preferred embodi-ment of the invention:
Figure 1 is a perspective view showing how the platter is used on a turntable system.
Figure 2 is a view in cross section of the disc.
In the following description words such as "outer", "inner", "top", and "bottom" are used in their relative sense only.
As shown in Figure 1 a disc 10 is positioned beneath a record 30 and a turntable platter 40 of a turn-table system (not shown). A clamping device 36 or a weight i5 fitted around the spindle 38 of the turntable system which turns with the platter 40 gripping the spindle and pressing down on the extremities of a labelled portion 34 of the record 30. The stylus then runs along the grooved portion 32 of the record to produce the sound. As seen in Figure 2 the disc 10 has a thermoplastic core 11 with a central aperture 12. The top surface of the core 11 has a ~s~
top inner annular recess 22 and a top outer annular recess
2~. The bottom surface of the core 11 has a bottom inner annular recess 21 concentrically aligned with the top inner annular recess 22 and a bottom outer annular recess 23 concentrically aligned with the top outer annular recess 24.
To the top inner annular recess 22 and the bottom outer annular recess 23 there is adhered respective polyvinyl cast foam mats 18 and 16 by means of pressure sensitive adhesive.
To the bottom inner annular recess 21 and a top outer annular recess 24 there is adhered by means of pressure sensitive adhesive a hard visco elastomeric material which consists of an aggregation of cork and jute particles suspended in a matrix of neoprene foam which forms mats 14 and 20, respectively. The core 11 is provided with a taper lS to the upper surface thereof such that the difference in thickness between the outer and inner extremities of the top and bottom outer annular recesses is 0.025 inches. This taper is necessary because the playing surface of a common record tapers up from the first cut to the last resulting in a slight incline from the outer periphery of the record to the label portion thereof. The record has its labelled portion clamped to the top inner mat 18, as a result of which the top playing surface of the record will be sub-stantially horizontal.
In order to achieve the close tolerances required in the outer surface of the disc 10, the upper outer annular mat 20 has its top surface ground after being affixed to the core 11.
Other variations, departures and modifications lying within the spirit of the invention and the scope as ~S~6~
defined in the appended claims will be obvious to those skilled in the art.
To the top inner annular recess 22 and the bottom outer annular recess 23 there is adhered respective polyvinyl cast foam mats 18 and 16 by means of pressure sensitive adhesive.
To the bottom inner annular recess 21 and a top outer annular recess 24 there is adhered by means of pressure sensitive adhesive a hard visco elastomeric material which consists of an aggregation of cork and jute particles suspended in a matrix of neoprene foam which forms mats 14 and 20, respectively. The core 11 is provided with a taper lS to the upper surface thereof such that the difference in thickness between the outer and inner extremities of the top and bottom outer annular recesses is 0.025 inches. This taper is necessary because the playing surface of a common record tapers up from the first cut to the last resulting in a slight incline from the outer periphery of the record to the label portion thereof. The record has its labelled portion clamped to the top inner mat 18, as a result of which the top playing surface of the record will be sub-stantially horizontal.
In order to achieve the close tolerances required in the outer surface of the disc 10, the upper outer annular mat 20 has its top surface ground after being affixed to the core 11.
Other variations, departures and modifications lying within the spirit of the invention and the scope as ~S~6~
defined in the appended claims will be obvious to those skilled in the art.
Claims (8)
1. A disc for supporting a record on a turntable platter, comprising:
(a) a core including:
(i) a central aperture for slidably receiving a spindle of a turn-table platter;
(ii) a planar bottom surface having a bottom inner annular recess for concentric alignment with the labelled portion of a record and an outer annular recess for concentric alignment with the grooved portion of a record;
(iii) a planar top surface having a top inner annular recess concentrically aligned with the bottom inner annular recess and substantially parallel thereto and a top outer annular recess concentrically aligned with said bottom outer annular recess;
(b) a top inner annular mat of soft visco elastomeric material suitable for dampening microvibrations said mat matingly received by and bonded to said top inner recess of said core;
(c) a top outer annular mat of hard nonreactive hard visco elastomeric material made up of particles which dissipate and dampen microvibrations, said particles being suspended in a resilient matrix which isolates the particles from one another and said hard nonreactive material being matingly received by and bonded to said top outer recess of said core;
(d) a bottom inner annular mat of said hard nonreactive material matingly received by and bonded to said bottom inner annular recess;
(e) a bottom outer annular mat of said soft material matingly received by and bonded to said bottom outer annular recess.
(a) a core including:
(i) a central aperture for slidably receiving a spindle of a turn-table platter;
(ii) a planar bottom surface having a bottom inner annular recess for concentric alignment with the labelled portion of a record and an outer annular recess for concentric alignment with the grooved portion of a record;
(iii) a planar top surface having a top inner annular recess concentrically aligned with the bottom inner annular recess and substantially parallel thereto and a top outer annular recess concentrically aligned with said bottom outer annular recess;
(b) a top inner annular mat of soft visco elastomeric material suitable for dampening microvibrations said mat matingly received by and bonded to said top inner recess of said core;
(c) a top outer annular mat of hard nonreactive hard visco elastomeric material made up of particles which dissipate and dampen microvibrations, said particles being suspended in a resilient matrix which isolates the particles from one another and said hard nonreactive material being matingly received by and bonded to said top outer recess of said core;
(d) a bottom inner annular mat of said hard nonreactive material matingly received by and bonded to said bottom inner annular recess;
(e) a bottom outer annular mat of said soft material matingly received by and bonded to said bottom outer annular recess.
2. A disc as defined by claim 1, wherein said hard nonreactive material is an aggregation of cork and jute particles held in a matrix of resilient material.
3. A disc as defined by claim 1, wherein said soft material is a nitrogen filled polyvinyl cast foam having a density of 20 pounds per cubic foot.
4. A disc as defined in claim 1, 2, or 3, wherein said core is a thermoplastic material.
5. A disc as defined by claim 1, 2, or 3, wherein the top outer annular recess is tapered away from the bottom outer annular recess in a direction radially outwardly from the center of said core at an angle such that when the center of the core is pressed into contact with said upper inner annular mat, the bottom grooved surface of the record is in intimate contact with said upper outer annular mat and an upper grooved surface of the record is substantially flat.
6. A disc for supporting a record on a turn-table platter comprising:
(a) a core of thermal plastic material including (i) a central aperture for slidably recei-ving a spindle of said turntable platter;
(ii) a flat bottom surface having a bottom inner annular recess for positioning concentrically and coextensively with the labelled portion of a record and an outer annular recess for position-ing concentrically and coextensively with the grooved portion of a record, (iii) a top surface having a top inner annu-lar recess coextensive and aligned with said bottom inner annular recess and substantially parallel thereto and a top outer annular recess coextensive and concentric with said bottom outer annular recess said top outer annular recess being tapered away from said bottom outer annular recess in a direction radially outwardly from the center of said core at an angle such that when the center of the record is pressed into contact with said upper inner annular mat the bottom grooved surface of the record is in intimate contact with said upper outer annular mat and the upper grooved surface of the record is substantially horizontal;
(b) a top inner annular mat of a nitrogen filled polyvinyl cast foam of a density of 20 pounds per cubic foot;
(c) a top outer annular mat of a nonreactive material being an aggregation of cork and jute particles held in a matrix of resilient material;
(d) a bottom inner annular mat of said nonreac-tive material matingly received by and bonded to said bottom inner recess;
(e) a bottom outer annular mat of said foam material matingly received by and bonded to said bottom outer recess.
(a) a core of thermal plastic material including (i) a central aperture for slidably recei-ving a spindle of said turntable platter;
(ii) a flat bottom surface having a bottom inner annular recess for positioning concentrically and coextensively with the labelled portion of a record and an outer annular recess for position-ing concentrically and coextensively with the grooved portion of a record, (iii) a top surface having a top inner annu-lar recess coextensive and aligned with said bottom inner annular recess and substantially parallel thereto and a top outer annular recess coextensive and concentric with said bottom outer annular recess said top outer annular recess being tapered away from said bottom outer annular recess in a direction radially outwardly from the center of said core at an angle such that when the center of the record is pressed into contact with said upper inner annular mat the bottom grooved surface of the record is in intimate contact with said upper outer annular mat and the upper grooved surface of the record is substantially horizontal;
(b) a top inner annular mat of a nitrogen filled polyvinyl cast foam of a density of 20 pounds per cubic foot;
(c) a top outer annular mat of a nonreactive material being an aggregation of cork and jute particles held in a matrix of resilient material;
(d) a bottom inner annular mat of said nonreac-tive material matingly received by and bonded to said bottom inner recess;
(e) a bottom outer annular mat of said foam material matingly received by and bonded to said bottom outer recess.
7. A disc as defined by claim 6, wherein said angle of taper is such that the difference in the thickness of said core at the outer extremity of said upper and lower outer recesses and the inner extremity thereof is 0.025 inches.
8. A disc as defined by claim 6, wherein said resilient material is neoprene sponge.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000372129A CA1145267A (en) | 1981-03-03 | 1981-03-03 | Disc |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000372129A CA1145267A (en) | 1981-03-03 | 1981-03-03 | Disc |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1145267A true CA1145267A (en) | 1983-04-26 |
Family
ID=4119357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000372129A Expired CA1145267A (en) | 1981-03-03 | 1981-03-03 | Disc |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1145267A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0261895A2 (en) * | 1986-09-20 | 1988-03-30 | Mitsubishi Petrochemical Co., Ltd. | Turntable of thermoplastics polymer for playing recorded discs |
| US5258972A (en) * | 1990-06-25 | 1993-11-02 | Msc Technology Corporation | Magnetic damping disc for improved CD player performance |
| EP1020849A3 (en) * | 1999-01-14 | 2005-01-19 | Vestax Corporation | Record player |
| GB2415824A (en) * | 2004-02-21 | 2006-01-04 | Arthur Haroutoun Khoubesserian | Turntable with foam support surface |
| WO2007077407A1 (en) * | 2006-01-03 | 2007-07-12 | Arthur Haroutoun Khoubesserian | A support member for a disc record |
-
1981
- 1981-03-03 CA CA000372129A patent/CA1145267A/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0261895A2 (en) * | 1986-09-20 | 1988-03-30 | Mitsubishi Petrochemical Co., Ltd. | Turntable of thermoplastics polymer for playing recorded discs |
| EP0261895A3 (en) * | 1986-09-20 | 1989-11-23 | Mitsubishi Petrochemical Co., Ltd. | Turntable of thermoplastics polymer for playing recorded discs |
| US5258972A (en) * | 1990-06-25 | 1993-11-02 | Msc Technology Corporation | Magnetic damping disc for improved CD player performance |
| EP1020849A3 (en) * | 1999-01-14 | 2005-01-19 | Vestax Corporation | Record player |
| GB2415824A (en) * | 2004-02-21 | 2006-01-04 | Arthur Haroutoun Khoubesserian | Turntable with foam support surface |
| GB2415824B (en) * | 2004-02-21 | 2007-04-25 | Arthur Haroutoun Khoubesserian | Sound reproduction apparatus |
| WO2007077407A1 (en) * | 2006-01-03 | 2007-07-12 | Arthur Haroutoun Khoubesserian | A support member for a disc record |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |