JPS6146883B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tone arm assembly for a record player.

A tone arm in a record player is electrically and mechanically integrated with a rotating mechanism such as a tone arm rotating shaft and a bearing that receives the rotating shaft. Therefore, the cartridge is replaced by removing the plug-in head shell, cursor, etc. from the tone arm, but in such a structure, the connection part with the tone arm is not strong and harmful partial resonance may occur. There are drawbacks that arise. Additionally, since the tone arm rotates horizontally and vertically, the lead wires installed in the tone arm and rotation shaft must be as thin and flexible as possible to reduce the mechanical resistance caused by the lead wires. . However, if the lead wires are thin and soft, the electrical resistance will increase, which may adversely affect the output voltage, S/N, sound quality, etc., especially when using cartridges with low internal impedance. This also reduces the mechanical strength of the lead wires and causes wire breakage.

Furthermore, with integrated pickups in which the tone arm body and cartridge etc. are integrated, the entire tone arm must be replaced when replacing the cartridge, but the tone arm cannot be separated from the rotation mounting mechanism. The drawback is that it is difficult to replace.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tone arm assembly that eliminates the above-mentioned drawbacks, allows for extremely easy replacement of the tone arm, and allows for a reduction in the effective mass of the arm body.

The present invention will be explained below using the drawings.

FIG. 1 shows an embodiment of the tone arm main body of the present invention, and is a side view including a partial cross section. In the figure, a cartridge 4 is attached to a fixing screw 18 at the tip of the arm 1, and the pickup output of the cartridge 4 is led out by a lead wire 8, passes through the inside of the arm 1, and is guided to the vicinity of the rotation center of the arm. Near the center of rotation, there is a contact 7 that serves as a connector.
is provided and connected to the lead wire 8.

An arm mounting screw 5 is provided substantially on the vertical axis of rotation of the tone arm 1 and is inserted through the arm so as to be slidable up and down. A stopper 6 is provided to prevent the mounting screw 5 from coming off the arm 1. Reference numeral 3 denotes a weight, and by sliding it on a sliding groove 2 provided in the arm 1, the stylus pressure of the cartridge can be adjusted.

FIG. 2 is a diagram showing an embodiment of the tone arm mounting mechanism according to the present invention, in which a is a plan view and b is a side view. In the figure, a rotation shaft 14, which is the center of rotation of the tone arm in the horizontal direction, is rotatably attached to an arm stand 13 and fixed to a cabinet or the like via the stand 13. An outer holder 12 attached to the rotation shaft is provided above the rotation shaft, and this holder 12 is provided with a horizontal shaft 11 perpendicular to the rotation shaft 14 . Arm mounting base 9
is rotatably supported in a vertical direction about a shaft 11, and the tone arm is mounted on a plane substantially perpendicular to the rotation shaft 14. In order to fix the tone arm on the mounting base 9, a mounting base 9 is placed on the mounting base 9, which is located on the almost vertical axis of rotation of the tone arm, for example, the mounting base 9.
An opening 17 is formed at the location where the axis of rotation intersects the center line of the rotating shaft 14
are provided to serve as screw holes, and terminals 10 for electrical connection serving as connectors are provided on the mounting surface. At the other end 15 of the terminal 10, the rotating shaft 14
It is connected to a lead wire 16 wired inside.

As described above, the fixing means for fixing the vicinity of the rotation center of the tone arm 1, that is, the mounting portion, to the arm mounting base 9 includes the screw hole 17 provided on the mounting base 9;
Mounting screw 5 provided through the mounting part of the arm
The tone arm is located approximately on the vertical axis of rotation of the tone arm. in this way,
By locating the fixing means almost on the vertical axis of rotation of the tone arm, the mass of the weight 3 can be reduced by the mass of the fixing means, so the effective mass of the tone arm body consisting of the tone arm 1, weight 3, and cartridge 4 is reduced. do. By reducing the effective mass, the tracing performance of the tone arm main body, that is, the ability to follow the eccentricity and warpage of a record, is improved, and the low-frequency resonance frequency ₀ can be set to a desired frequency. Here, the desirable frequency refers to a frequency of around 10Hz. After all, if the low resonance frequency ₀ is too high, the musical tone (20 to 20,000
Hz), and if it is too low, cross-modulation distortion will occur due to frequency components (around 5Hz) based on the eccentricity and warpage of the record, so 10Hz.
The front and rear are preferable.

FIG. 3 shows a partially cross-sectional side view of the tone arm 1 shown in FIG. 1 when it is attached to the attachment mechanism shown in FIG. 2. In FIG. 3, the same parts as those in FIGS. 1 and 2 are given the same reference numerals, and the arm stand 13 is omitted for simplicity. As shown in the figure, the mounting screw 5 of the arm 1 is inserted and fitted into the screw hole 17 of the arm mounting base 9, so that the arm 1 is fixed. At this time,
The contact 7 of the arm 1 is the connection terminal 1 on the mounting base 9
0, which electrically connects the lead wire 8 of the tone arm 1 and the lead wire 16 inside the rotating shaft 14 of the mounting mechanism, and these contacts 7 and the connection terminal 10 This means that they form a connector.

With this configuration, the tone arm 1 rotates horizontally with the rotation of the rotation shaft 14, and since the arm mounting base 9 is rotatable around the horizontal axis 11, the tone arm 1 also rotates vertically around the horizontal axis. It is possible to rotate in the direction.

In order to determine the mounting direction and mounting position of the tone arm 1 on the mounting base 9, the structure of the mounting base 9 is shown in a plan view in FIG. 4a and in a side view in FIG. 4b, for example. That is, sloped portions 19 directed outward are formed on two sides of the mounting base 9 parallel to the axial direction of the arm 1. As shown in the schematic cross-sectional view of FIG. 5, a tone arm is mounted on this inclined portion 19 so that both lower edge portions parallel to the axis of the tone arm 1 are aligned with each other and screwed. The mounting direction and mounting position are determined regardless of the mounting error between the screw 5 and the screw hole 17. Therefore, the inclined portion 19 of the mounting base 9
serves as a guide when attaching the arm.

As described above, according to the present invention, the tone arm body can be attached to and detached from the arm attachment mechanism using only the attachment screws, and electrically, it can be easily separated and connected using the connectors 10 and 7. Replacement is very easy, and the lead wire 8 can be made of a thick wire, so that the electrical resistance of the lead wire can be reduced. In addition, by locating the means for fixing the arm body to the mounting base almost on the vertical axis of rotation of the arm, the effective mass of the arm body can be reduced, thereby improving tracing performance and lowering the low-frequency resonance frequency to _10Hz . You can set the desired frequency before or after. Furthermore, the cartridge can be replaced while the arm body is separated from the attachment mechanism. Further, since the cartridge, tone arm, and weight are replaced as one unit, it is possible to always select a tone arm and weight for various cartridges according to the characteristics such as mass and compliance of the cartridge. Furthermore, since the bearing portion can be shared by all tone arms, if the bearing portion is manufactured with high precision, a highly sensitive tone arm assembly can always be provided.

[Brief explanation of the drawing]

FIG. 1 is a side view including a partial cross section of the tone arm according to the present invention, FIG. 2 is a diagram showing the arm mounting mechanism section according to the present invention, a is a plan view, b is a side view, and FIG. FIG. 4 is a side view including a partial cross section of an embodiment of the invention; FIG. 4 is a diagram showing an example of an arm mounting base; a is a plan view; b is a side view; FIG. 5 is a schematic diagram showing the relationship between the arm mounting base and the arm. FIG. Explanation of symbols of main parts, 1...Tone arm,
4... Cartridge, 5... Mounting screw, 7... Contact, 8, 16... Lead wire, 9... Arm mounting base, 10... Connection terminal, 11... Horizontal axis, 14
... Rotating shaft, 17 ... Screw hole, 19 ... Inclined part.

Claims (1)

[Scope of Claims] 1. A tone arm having a weight at its rear end, capable of supporting a cartridge at its tip, and having a mounting portion at an intermediate portion; an arm mounting base that cooperates to determine the mounting direction and mounting position of the tone arm unit; a rotation bearing unit that supports the arm mounting base so as to be rotatable in horizontal and vertical directions; and the mounting unit. A tone arm assembly comprising: fixing means for fixing to the arm mounting base, the fixing means being provided so as to be positioned substantially on a vertical axis of rotation. 2. The fixing means comprises a screw hole provided on the arm mounting base, and a mounting screw provided through the mounting portion and screwed into the screw hole. The tone arm assembly according to item 1.