US3850435A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gramophone pickup guidance mechanisms
Assignee: Individual
•
Filing: 1973-12-20
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Granted: 1974-11-26
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Expires: 1993-12-20
Abstract
Abstract A pickup guidance mechanism for gramophone disc records comprising a pickup which can receive a stylus for engaging a groove on the record, an arm on which the pickup is carried for guidance across the record and which is pivoted for rotation in a plane parallel to the record, a source of radiation which emits radiation in a path, part at least of which extends in a radial direction with respect to the record rotation axis and sensing means responsive to said radiation and adapted whenever the pickup arm departs from a mean position in which tracking error is zero, to produce a command signal which effects return movement of the arm towards said mean position.
Inventors
- 👤 R Birch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:02
CPC Classifications
G; G11; G11B; G11B3/00; G11B3/02; G11B3/10; G11B3/12; G11B3/28; G11B3/34; G11B3/38
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
372 words
A pickup guidance mechanism for a gramophone disc record player in which a gramophone disc record having a spiral groove containing a recorded signal is rotatable by turntable means which define a record axis of rotation and a record plane at right angles thereto, comprising: A. a pickup which can receive a stylus for engaging said spiral groove on the record and which experiences deflections to opposite sides of a symmetry plane when engaged with said groove upon rotation of the record on the turntable means; B. a first or pickup arm holding the pickup for guidance thereof across the record and pivoted for rotation in a plane parallel to the record plane about an axis which lies in the symmetry plane and is remote from the pickup; C. a slave arm mounted for rotation in a plane parallel to the record plane and pivotally supporting said first arm at said first arm axis; D. a radiation propagation and sensing system having elements so disposed in relation to the first arm and the record axis as to afford, in a position of the first arm in which tracking error is zero, i.e., when the symmetry plane is normal to the radial plane of the record containing an axis parallel with the record axis and passing through the point of engagement with the record of the stylus in its undeflected position a radiation path which includes a line joining the record axis with said axis parallel with the record axis or a segment of that line, one of said elements of the system being mounted in said radiation path on said axis parallel with the record axis so as to be movable with said first arm and to effect, during operative engagement of the stylus on the record, on movement of said first arm, a change in the distribution of radiation sensed by the system thereby to produce, when said first arm is in a position other than said position thereof in which tracking error is zero, a command signal; and E. correcting means responsive to said command signal and adapted to rotate the slave arm to effect movement of said first arm towards said position thereof in which tracking error is zero.
Claim 2
Dependent Claim
372 words
A pickup guidance mechanism for a gramophone disc record player in which a gramophone disc record having a spiral groove containing a recorded signal is rotatable by turntable means which define a record axis of rotation and a record plane at right angles thereto, comprising: A. a pickup which can receive a stylus for engaging said spiral groove on the record and which experiences deflections to opposite sides of a symmetry plane when engaged with said groove upon rotation of the record on the turntable means; B. a first or pickup arm holding the pickup for guidance thereof across the record and pivoted for rotation in a plane parallel to the record plane about an axis which lies in the symmetry plane and is remote from the pickup; C. a slave arm mounted for rotation in a plane parallel to the record plane and pivotally supporting said first arm at said first arm axis; D. a radiation propagation and sensing system having elements so disposed in relation to the first arm and the record axis as to afford, in a position of the first arm in which tracking error is zero, i.e., when the symmetry plane is normal to the radial plane of the record containing an axis parallel with the record axis and passing through the point of engagement with the record of the stylus in its undeflected position a radiation path which includes a line joining the record axis with said axis parallel with the record axis or a segment of that line, one of said elements of the system being mounted in said radiation path on said axis parallel with the record axis so as to be movable with said first arm and to effect, during operative engagement of the stylus on the record, on movement of said first arm, a change in the distribution of radiation sensed by the system thereby to produce, when said first arm is in a position other than said position thereof in which tracking error is zero, a command signal; and E. correcting means responsive to said command signal and adapted to rotate the slave arm to effect movement of said first arm towards said position thereof in which tracking error is zero.
Claim 3
Dependent Claim
47 words
A mechanism as claimed in claim 1, wherein the record plane and said line of the radiation path are spaced apart and said line or said segment thereof lies within the radiation when the first arm is in the position thereoF in which tracking error is zero.
Claim 4
Dependent Claim
46 words
A mechanism as claimed in claim 1, wherein the radiation propagation and sensing system includes a source of radiation and sensing means, the source of radiation being arranged so that the sensing means are scanned by the radiation from the source during rotation of a record.
Claim 5
Dependent Claim
30 words
A mechanism as claimed in claim 1, wherein the radiation propagation and sensing system includes a radiation source which is a light source and sensing means which are photocell means.
Claim 6
Dependent Claim
25 words
A mechanism as claimed in claim 1, wherein said line of the radiation path is disposed above the level of a baseboard of the mechanism.
Claim 7
Dependent Claim
38 words
A mechanism as claimed in claim 5, wherein the radiation propagation and sensing system includes a radiation source and/or sensing means carried on a turret removably mounted on a spindle of the turntable means of the record player.
Claim 8
Dependent Claim
53 words
A mechanism as claimed in claim 6, wherein the radiation propagation and sensing system includes a radiation reflector mounted in fixed relationship with respect to the pickup, and the turret carries both the source of radiation and sensing means of said system towards which sensing means the reflector directs radiation from the source.
Claim 9
Dependent Claim
25 words
A mechanism as claimed in claim 1, wherein said line of the radiation path is disposed below the level of a baseboard of the mechanism.
Claim 10
Dependent Claim
91 words
A mechanism as claimed in claim 8, wherein there is provided, mounted for rotation together with the pickup arm, in a plane parallel with the record plane and located below the level of a baseboard of the mechanism, a further, so-called, ''''ghost'''' arm contained in the same plane normal to the record plane as the pickup arm, the ghost arm carrying one of the elements of the radiation propagation and sensing system on the axis parallel with the record axis through the point of engagement of the stylus with the record.
Claim 11
Dependent Claim
114 words
A mechanism as claimed in claim 9, wherein the radiation propagation and sensing system includes a radiation source which is a light source and sensing means towards which the light source is directed and which comprises a pair of photocells and a mask which cooperates with the photocells so that in the position of the pickup arm in which tracking error is zero, the cells are equally illuminated by the light source while in positions of the pickup arm departed from the zero tracking error position in respective opposite senses the cells are differentially illuminated in opposite manners corresponding with the senses of departure from its zero tracking error position of the pickup arm.
Claim 12
Dependent Claim
61 words
A mechanism as claimed in claim 10, wherein the light source is mounted at the record rotation axis and the photocells are disposed symmetrically on opposite sides of the light source with their sensing surfaces coplanar and containing the record rotation axis, the ghost arm carrying, below the pickup stylus, a mirror for reflecting light from the source to the photocells.
Claim 13
Dependent Claim
45 words
A mechanism as claimed in claim 11, wherein the light source and/or photocells are mounted so as to rotate with the record whereby scanning of the photocells by the light beam from the source is effected at least once during each revolution of the record.
Claim 14
Dependent Claim
102 words
A mechanism as claimed in claim 10, wherein the radiation propagation and sensing system includes a reflector mounted on the ghost arm and further includes a plurality of light sources mounted in equiangularly spaced relationship round the record rotation axis and a plurality of pairs of photocells, the cells of each pair of which are symmetrically arranged with respect to a light source, the light sources and the cells being mounted so as to rotate with the record whereby scanning of the photocells by the light from the sources being reflected by the reflector is successively effected during revolution of the record.
Claim 15
Dependent Claim
80 words
A mechanism as claimed in claim 4, wherein the radiation propagation and sensing system includes a reflector fixed with respect to the pickup anD disposed on the axis parallel with the record axis through the point of engagement with the record of the stylus and the radiation path extends from the record rotation axis to the rotation axis of the pickup arm on the slave arm, the light source and sensing means being located at opposite ends of said path.
Claim 16
Dependent Claim
87 words
A mechanism as claimed in claim 4, wherein the radiation propagation and sensing system includes a reflector fixed with respect to the pickup and disposed on the axis parallel with the record axis through the point of engagement with the record of the stylus, the radiation path extending from the record rotation axis to a point on the circumference of a circle which intersects the record rotation axis and said axis parallel thereto, the light source and sensing means being located at opposite ends of said path.
References Cited (Backward Citations)
US2915315A
Cited
US3272513A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |