Dynamic information storage or retrieval – Specific detail of information handling portion of system – Mechanical modification or sensing of storage medium
Patent
1980-08-26
1983-08-02
Cardillo, Jr., Raymond F.
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Mechanical modification or sensing of storage medium
369147, H04R 916
Patent
active
043970125
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to means for reproducing recorded sound by the use of a stylus and in particular to electrodynamic pickup cartridges.
PRIOR ART
Known in the art are electrodynamic pickup cartridges with coils moving back and forth in a magnetic field set up by a magnetic system (cf. Orthophone SPUT cartridge; A. N. Bektabegov "Stereophonic Pickups," "Energy" publishers, Moscow, 1964).
The aforesaid cartridges comprise a constuctionally intricate and bulky magnetic system composed of a permanent magnet and cores to produce a uniform magnetic field. As stated above, such cartridges incorporate moving coils which are difficult to manufacture and have a small number of turns, a disadvantage resulting in a low e.m.f. This calls for the utilization of a step-up transformer, which also complicates the construction of the afore-mentioned cartridges. In such cartridges the e.m.f. is produced essentially in the same manner as in systems wherein a frame is moved back and forth in a magnetic field.
Also known in the art are electrodynamic pickup cartridges comprising two reproduction channels provided with cylindrical coils accommodating permanent magnets installed on a stylus holder which is common to both channels and carries the stylus so that unlike poles thereof project on both sides of the stylus holder and their axes along the N-S line are found in planes crossing at a standard recording angle (cf. cartridge disclosed in U.S. Pat. No. 4,237,347 obtained by, among others, the present inventor).
In such cartridges the coil of each reproduction channel represents a two-section structure. Each section of the coil encompasses one of the pokes of a respective magnet. The coil is so disposed relative to its magnet that the longitudinal axis thereof coincides with the magnet axis along the N-S line. This substantially complicates production and construction of the cartridges and prevents replacement of a stylus holder by the user in operation since the coil sections are to be drawn apart to enable stylus holder replacement, a disadvantage necessitating disassembly of the cartridges.
BRIEF SUMMARY OF THE INVENTION
The present invention resides in providing an electrodynamic pickup cartridge wherein a coil structure permits substantially simplifying construction and production of the cartridge and assures easy replacement of a stylus holder by the user in operation.
The foregoing object is accomplished by that in an electrodynamic pickup cartridge comprising two reproduction channels provided with cylindrical coils accommodating permanent magnets installed on a stylus holder which is common to both channels and carries a stylus so that unlike poles thereof project on both sides of the stylus holder, while their axes along the N-S line are found in planes crossing at a standard recording angle, according to the invention, the coil of each reproduction channel represents a single-section structure so disposed relative to its magnet that it encompasses both poles of said magnet and longitudinal axis thereof is perpendicular to the axis of said magnet along the N-S line.
Preferably the cylindrical coil of each reproduction channel is elongated in cross-section and oriented so that turns thereof are close to the poles of the magnet of its channel and far from the poles of the magnet of the other channel.
The electrodynamic pickup cartridge forming the subject of the present invention boasts of simplier construction and easier production procedure. Furthermore, it permits bringing the magnet of one channel closer to the magnet of the other channel, which generally improves dynamic properties of the stylus holder, another advantage being the possibility of stylus holder replacement without disassembly of the cartridge.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described further with reference to specific embodiments thereof, taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a general view of an electrodynamic pickup cartridge according to the
REFERENCES:
patent: 1768377 (1930-06-01), Serduke
patent: 3014993 (1961-12-01), Narma
patent: 4209669 (1980-06-01), Hayashi
patent: 4237347 (1980-12-01), Burundukov et al.
High-Class Pickup Cartridge; Praktiker, 1977, vol. 33, N24, Asterr., p. 37.
cf. Orthophone SPUT Cartridge; A. N. Bektabegov; "Stereophonic Pickups", Energy publishers, Moscow, 1964.
Electromagnetic Pickup; E. Ahrens, Erhard, Dr., 2300 Kiel; Knospe, Dieter, 2308 Preetz, Wichmann, Burkhard, 2300 Kiel 1979; No. 17.
High-Class Pickup Cartridge; Spitzenklasse-Tonabnehmersystem, "Praktiker", (Asterr.), 1977, 33, No. 24,37.
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