JPS6038764B2 - Pickup Cartridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup cartridge, in which a resonant frequency can be adjusted arbitrarily by providing a rigid body that corresponds to a record with a viscoelastic member whose elastic component can be adjusted arbitrarily. An object of the present invention is to provide a pickup cartridge capable of reproducing records with high precision.

In general, the resonant frequency fo of a pickup arm (hereinafter referred to as arm) is expressed by the following equation, where S is the elasticity of the vibration system such as a cantilever or armature, and M is the effective mass of the arm. It is set at an appropriate frequency that does not follow ultra-low frequencies such as warping of a record, and allows reproduction of relatively high-frequency audio signals without cutting them.

Therefore, in order to reliably reproduce the audio signal,
It is common practice to apply a brake to the arm. As a method of applying a brake to the arm, a brake element 2 is provided at the base of the arm 1 as shown in FIG. There is something that brakes the

However, since the vibration of the arm is damped at its base, if the arm 1 vibrates within the range indicated by the broken line as shown in Figure A, the damping effect is small and the damping cannot be achieved reliably. Ta. In addition, as shown in the equivalent schematic diagram and equivalent circuit diagram in B and C of the same figure, respectively, the amount of braking R by the brake element 2 is
When is large, (pickup output i,) = (vibration source output io), which makes it easy to detect unnecessary signals in the ultra-low frequency band such as warpage of the record, and also causes distortion of the cantilever due to warpage of the record. Since the vertical angle changes greatly, the linearity of the output tends to change, which has the disadvantage that the original audio signal in the audible band is modulated. In addition, as another method of applying braking to the arm, conventionally, as shown in FIG. 2A, a cartridge 4 is used.
There is a device in which a support body 5 provided with a brush 5' is provided rotatably in the vertical direction, and the rotation axis of the support body 5 is rotated via a viscous agent to brake the arm.

However, as shown in the equivalent schematic diagram and equivalent circuit diagram in FIG. The effect of cutting off and damping near the resonant frequency fo is better than that shown in FIG. 1A. However, this method cannot adjust the resonance frequency itself, and when the resonance frequency is low, it detects ultra-low frequency components such as warping of a record, or detects the resonance frequency f. If it is high, there will be an inconvenience that the original low frequency signal will be cut. Resonance frequency is generally determined by a combination of the low-frequency conformance of the vibrator and the effective mass of the arm, and the above-mentioned problems are likely to occur when combining vibrators and arms that have different characteristics. However, those with low mechanical impedance, especially in the low range, generally have large compliance near fo, and therefore,
The resonance frequency fo tends to become too low. Therefore, when trying to reduce the mass of the arm in order to eliminate the above-mentioned disadvantages, the rigidity of the arm tends to become rigid.
There were drawbacks such as the generation of high-order split vibrations of the arm in the audible range. In this way, since conventional pickup cartridges only have a brake at the base of the arm or a brake at the tip of the arm, the equivalent elasticity S of the cantilever and armature itself can be adjusted arbitrarily. For this reason, the resonant frequency fo itself cannot be adjusted, and when arms, cartridges, etc. are freely combined, problems tend to occur.

The present invention eliminates the above-mentioned drawbacks, and each embodiment thereof will be described with reference to FIG. 3 and subsequent figures.

FIG. 3 shows the first pickup cartridge according to the present invention.
A perspective view of an example is shown. In the figure, reference numeral 6 denotes an L-shaped support body, which is fixed to the upper surface of the cartridge body 7 with screws or the like. 8 is a bar, one end of which is rotatably supported by a shaft 9 provided as a shield on the side surface of the support body 6, and a felt 11 is attached to the lower surface of the end.

Reference numeral 12 denotes a U-shaped guide rail, which is fixed to the side surface of the support body 6 parallel to the upper surface of the cartridge body 7.

Reference numeral 13 denotes a viscoelastic member support, and as shown in FIG. 4, a viscoelastic member (hereinafter referred to as rubber) 14 having an elastic component and a viscous component is fixed to the lower surface, and is provided on the rail 12 so as to be slidable in the longitudinal direction. The structure is fixed to the rail 12 with screws 15.

The felt 11 provided at the tip of the lever 8 is brought into contact with a record (not shown) with a predetermined pressure due to the downward elastic force of the rubber 14. Reference numeral 16 denotes a stopper, which is protruded at the lower side of the support body 6, and is configured to prevent the lever 8 from rotating unnecessarily when the cartridge 6 is raised above the record.

Here, cantilever 17 and bar 8 are placed on the record.
are supported in parallel, the elasticity S of the vibrating system
is the stiffness Sc at the base of the cantilever 17
It is expressed as the sum (Sc + SR) of the effective stiffness SR seen from the contact point on the record by the bar 8, and as a result, the resonance frequency of the arm, f.

= Abutsu = Mugi Tang Becomes a business owner. On the other hand, as shown in Figure 4,
The elastic component of the rubber 14 is SP, the distance from the fulcrum (screw) 9 to the felt 11 of the bar 8 is
If the distance to the contact point with 4 is s, then the stiffness SR' is expressed as SR=sPX.

Therefore, by appropriately displacing the position of the rubber 14 to vary the distance, the stiffness SR can be freely varied and the resonant frequency fo can be freely adjusted.

As described above, the pickup cartridge of the present invention is
Okayama body lever 8, cantilever 8, cantilever 17
The lever 8 is brought into contact with the record in parallel, and the pressure force applied to the record by the lever 8 can be adjusted by the rubber 14. Can be adjusted freely, the first
Compared to conventional pickup cartridges as shown in Figures A and 2A, the value of the resonant frequency fo itself can be varied, so appropriate resonant frequencies can be set for the arms and vibrators, each of which has a variety of different characteristics. These can be freely combined and used, and have the feature of high versatility.

Regarding braking of the arm, the rotational displacement of the arm is suppressed by the viscous component of the rubber 14. Next, the resonant frequency fo
The adjustment method will be explained below.

A signal with a frequency of 5Hz ~ 30 days 2 is recorded at the same relatively high level at intervals of 2 days from IHz ~ 2 days for a specified period of time, and the fourth
In the figure, the rubber 14 of the rubber support 13 is set at an appropriate position, the screw 15 of the support 13 is tightened, the test record is traced, and the output level is measured.

Here, when tracing the groove in the vicinity of the resonance frequency RA' in this cartridge, the cartridge output level increases, and the frequency at this time is the resonance frequency RA' of this cartridge when the rubber 14 is set at the above position.
Next, the tracing is temporarily interrupted, and if the desired resonance frequency (generally set to approximately 10 days 2 to 15 days 2) is higher than the resonance frequency 9' at the time of the above measurement, the screw 15 of the rubber support 13 Loosen the lever and move the support 13 in the direction of the arrow b in FIG. They are respectively displaced in the a direction, that is, the side marked with the lever 8.

Trace the test record again, set the position of the leaf spring support 13 so that the desired resonance frequency matches the resonance frequency fo' at the time of measurement, and fix the support 13 to the rail 12 by tightening the screw 15. do. FIG. 5 shows a partially vertical front view of a main part of a second embodiment of the pickup cartridge according to the present invention.

In the figure, 18 is a bar support plate, and 18 is a bar support plate, and as shown in FIG. It is attached to the hole 20 with a screw 22 so as to be movable in the vertical direction in FIG. The support plate 18 has grooves 26a and 26b as shown in FIG.
A hole 26 is bored. In addition, support plate 1
The hole 8 is a blank hole, and the hole in the splice plate 21 is provided with a screw. 23 is a roughly L-shaped lever, with felt 24 pasted on the lower surface of one end, and a groove and hole 25 shaped like a pond.
is provided.

27 is a screw, and the sectional view along the W-skin line in Figure 5 is shown in Figure 7.
As shown in the figure, protrusions 27a and 27b that can be joined to grooves 26a and 26b of the support plate 18 are provided, and a threaded portion 28 is provided at the other end.

A wire 30 is fixed to one end of the screw 27 and has a locking portion 29 that is recessed into the groove 25 of the lever 23, and the other end protrudes outside the support plate 18 and is connected to the nut 31
is inserted. 32 is a rubber with a hole bored in the center, and the wire 30 is inserted into the hole to connect the lever 23 and the support plate 18.
is interposed between.

Here, when adjusting the resonance frequency, screw 2 of the support plate 18
2 to fix the support plate 18 at an appropriate height position on the support body 19, rotate the nut 31 to adjust the tensile strength of the wire 30, and adjust the major elasticity of the rubber 32.

As described above, the pickup cartridge of the present invention includes a rigid body provided near the stylus tip in contact with the record surface so as to be freely displaceable in the direction perpendicular to the record surface, and an elastic component and a viscous component provided near the stylus tip. Since the viscoelastic part that can arbitrarily adjust at least the size of the elastic component is provided in contact with the rigid body, by adjusting the elastic force of the viscoelastic part, the elastic force of the viscoelastic part can be adjusted to make it possible to adjust the magnitude of the elastic component arbitrarily. The effective stiffness of the pickup arm can be varied, and the resonance frequency of the pickup arm can be arbitrarily selected. Therefore, the optimal resonance frequency can be set for each vibrator and arm, each having a variety of different characteristics. can be used in any combination,
It can prevent the audio signal from being modulated by unnecessary ultra-low frequency components such as warping of a record, and even when the convergence of the transducer is increased, it can reduce the mechanical impedance of the transducer, which improves the tracing ability. It has features such as being able to improve

[Brief explanation of the drawing]

1A-C and 2A-C are respectively front views, equivalent schematic diagrams, and equivalent circuit diagrams of main parts of conventional pickup cartridges, and FIG. 3 is a first diagram of a pickup cartridge according to the present invention. FIG. 4 is a diagram for explaining the structure of the lever and viscoelastic member of the cartridge shown in FIG. 3, and FIG. 5 is a partial longitudinal section of the second embodiment of the pickup cartridge according to the present invention. The front view, FIG. 6, and FIG. 7 are a diagram for explaining the configuration of the lever support plate of the cartridge shown in FIG. 5, and a longitudinal sectional view taken along the skin line in FIG. 5, respectively. 6, 19... Support body, 7... Cartridge body, 8, 23...
Lever, 9... Shaft, 11, 24... Felt, 12... Guide rail, 13... Viscoelastic member support, 14, 32...
Majority elastic member (rubber), 15... Screw, 17... Cantilever, 18... Lever support plate, 27... Screw, 2
9...Locking part, 30...Wire, 31...Nut. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. A rigid body is provided in the vicinity of the needle tip of the cartridge body, etc., in contact with the record surface so as to be freely displaceable in a direction perpendicular to the record surface, and an elastic component and a viscous component are provided in the vicinity of the needle tip. 1. A pick-up cartridge comprising: a viscoelastic member having a viscoelastic member which can arbitrarily adjust the size of at least the elastic component, and is provided in contact with the rigid body. 2. The rigid body is a lever-shaped body whose one end is in contact with the record surface and the other end is rotatably supported in the vicinity of the needle tip in a direction perpendicular to the record surface, and the viscoelastic member is A pick-up cartridge according to claim 1, characterized in that the pick-up cartridge comprises a member that can be displaced in the longitudinal direction. 3. A rigid body is tensilely supported near the needle tip of the cartridge body etc. via a viscoelastic member having an elastic component and a viscous component so as to contact the record surface, and the tensile force can be adjusted as desired. A pick-up cart cartridge characterized by: