Patent US2890878A successfully refreshed from Google Patents.
US4121837A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Record player having a device for damping vibrations of a tone arm
Assignee: TOMINARI ENGINEERING Ltd NO 8-6 3-CHOME GINZA CHUO-KU TOKYO
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Filing: 1977-06-08
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Granted: 1978-10-24
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Expires: 1997-06-08
Abstract
Abstract A record player comprises a tone arm provided at the distal end thereof with a pickup cartridge, and a vibration damping device for damping a resonance of the tone arm. The damping device comprises a damping member made of an electrically conductive material and provided at the tone arm in a manner to vibrate unitarily therewith, and a damping unit inclusive of permanent magnet means for forming a magnetic field with respect to the damping member. Eddy currents are generated in the damping member when the damping member vibrates in the magnetic field, whereby damping of the vibration of the damping member and the tone arm is accomplished. The damping device may further comprise an elastic member supported at one end thereof at the tone arm and having another free end and a weight secured to the free end of the elastic member.
Inventors
- 👤 Noboru Tominari
- 👤 Hiroshi Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:32
CPC Classifications
G; G11; G11B; G11B3/00; G11B3/02; G11B3/10; G11B3/12; G11B3/125; G11B3/128
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
66 words
A record player comprising: a tone arm having a main arm and a sub-arm, said sub-arm being pivotably mounted with a shaft on a forward end of the main arm to rotate in swinging movement in a vertical plane and having a pickup cartridge mounted thereon; pivoting means for pivoting the main arm with a pivot shaft to rotate in swinging movement in a horizontal plane;
Claim 2
Dependent Claim
66 words
A record player comprising: a tone arm having a main arm and a sub-arm, said sub-arm being pivotably mounted with a shaft on a forward end of the main arm to rotate in swinging movement in a vertical plane and having a pickup cartridge mounted thereon; pivoting means for pivoting the main arm with a pivot shaft to rotate in swinging movement in a horizontal plane;
Claim 3
Dependent Claim
26 words
a damping plate made of an electrically conductive material having a substantially arcuate shape and secured to said main arm projecting in a lateral direction thereof;
Claim 4
Dependent Claim
26 words
a damping plate made of an electrically conductive material having a substantially arcuate shape and secured to said main arm projecting in a lateral direction thereof;
Claim 5
Dependent Claim
119 words
a damping unit having a pair of permanent magnets with a gap therebetween for insertion therein of said damping plate to form a magnetic field within said gap, said damping plate being displacable in the gap between the permanent magnets with swinging motion of the main arm; support means for supporting the damping unit in a position whereby the damping plate being insertable into the gap between the permanent magnets; a leaf spring supported at a first end thereof at said main arm whereby a second free end being adapted to vibrate in a horizontal plane and extends in a longitudinal direction of the main arm; and a weight being secured to said second end of said leaf spring.
Claim 6
Dependent Claim
119 words
a damping unit having a pair of permanent magnets with a gap therebetween for insertion therein of said damping plate to form a magnetic field within said gap, said damping plate being displacable in the gap between the permanent magnets with swinging motion of the main arm; support means for supporting the damping unit in a position whereby the damping plate being insertable into the gap between the permanent magnets; a leaf spring supported at a first end thereof at said main arm whereby a second free end being adapted to vibrate in a horizontal plane and extends in a longitudinal direction of the main arm; and a weight being secured to said second end of said leaf spring.
Claim 7
Dependent Claim
69 words
A record player as claimed in claim 1, further comprising: a first block for holding said pivoting means being rotatable integrally with the main arm in a vertical plane; said support means being defined by a horizontal shaft provided integrally with said first block; and a second block for bearing upon said supporting means so that the main arm, first block, and damping unit rotate in the vertical plane.
Claim 8
Dependent Claim
27 words
A record player as claimed in claim 2 further comprising: a base structure; and means for adjustably supporting the second block with respect to the base structure.
Claim 9
Dependent Claim
143 words
A record player comprising: a tone arm having a main arm and a sub-arm; said sub-arm being pivotably mounted with a shaft on a forward end of the main arm to rotate in swinging movement in a vertical plane and having a pickup cartridge mounted thereon; pivoting means for pivoting the main arm with a pivot shaft to rotate in swinging movement in a horizontal plane; a damping plate formed of an electrically conductive material secured to said sub-arm to project in a vertical direction thereof; a damping unit formed of a pair of permanent magnets having a gap therebetween for insertion therein of said damping plate to form a magnetic field within said gap, said damping plate being displacable in the gap between the permanent magnets with swinging motion of the sub-arm, and said damping unit being supported by the main arm.
Claim 10
Dependent Claim
143 words
A record player comprising: a tone arm having a main arm and a sub-arm; said sub-arm being pivotably mounted with a shaft on a forward end of the main arm to rotate in swinging movement in a vertical plane and having a pickup cartridge mounted thereon; pivoting means for pivoting the main arm with a pivot shaft to rotate in swinging movement in a horizontal plane; a damping plate formed of an electrically conductive material secured to said sub-arm to project in a vertical direction thereof; a damping unit formed of a pair of permanent magnets having a gap therebetween for insertion therein of said damping plate to form a magnetic field within said gap, said damping plate being displacable in the gap between the permanent magnets with swinging motion of the sub-arm, and said damping unit being supported by the main arm.
Claim 11
Dependent Claim
32 words
A record player as claimed in claim 4, comprising: an elastic member being supported substantially at one end thereof at said sub-arm and having another free end and a weight secured thereto.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-23 | 1982-04-24 | 1982-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-23 | 1986-04-24 | 1986-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-23 | 1990-04-24 | 1990-10-24 | $7700.00 | Window Closed / Lapsed |