JPS6115677Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a pick-up cartridge with an improved magnetic circuit.

Conventional magnetic circuits in pick-up cartridges, especially those in which the magnetic circuit is arranged parallel to the insertion hole of the replacement needle pipe holder, are divided into two pole pieces to which the coil is attached, and the coil is attached to one pole piece. After fitting, the other pole piece is fitted to the coil and integrated.
However, it has been difficult to fix each pair of pole pieces fitted to the coil with the casing, that is, it has been difficult to align the pole pieces with the hole into which the pipe holder is inserted.

This idea was made in view of the points mentioned above.
The purpose of this is to
By fixing the pole piece to the base and fitting the second pole piece into the coil fitted to the first pole piece and the pole piece insertion groove formed on the base, the first and second pole pieces are fixed. To provide a pick-up cartridge capable of fixing a two-pole piece to a base at an accurate position.

Another object of this invention is that by fixing a part of the second pole piece to the base with adhesive, the second pole piece can be securely fixed, and the second pole piece can also be fixed to the base with adhesive. To provide a pick-up cartridge which can effectively prevent pieces from protruding into a pipe holder insertion hole.

Next, an embodiment of this invention will be described with reference to the drawings.

A is a replacement needle, and a knob 1 made of resin is attached to the shield case 11 of the cartridge body, which will be described later, and a pipe holder 2 is fixed to the knob 1.
The cantilever 3 is elastically supported and fixed in the pipe holder together with a magnet (not shown), and the regeneration needle 4 is attached to the tip of the cantilever 3. The above structure is well known. The knob 1 has a guide hole 1a into which a projection _5a2 protruding from the shield case 11 is inserted.

The cartridge body includes a base 5 made of resin, a shield plate 6 placed on a horizontal piece 5b of the base 5, and a first pole piece 7 having a magnetic detection end molded on the vertical piece 5a of the base 5. and a coil 8 fitted into each of the pole pieces 7, and a second pole piece 9 fitted into the coil 8 and the long groove _5b2 of the base 5, and a pick-up device for protecting the pick-up device. In addition, a pedestal 10 is provided with a terminal pin 12 for leading the lead wire from the coil 8 to the outside, and a shield made of a magnetically conductive material such as permalloy, into which the pick-up device and the pedestal 10 are fitted. It consists of case 11.

Next, to explain the details of the structure of the pick-up device, the base 5 is formed in a substantially L-shape, and a protrusion 5a 1 is formed on the upper part of the vertical piece 5a, and a guide protrusion 5a ₂ is formed on the front surface of the protrusion 5a ₁ . is formed, and a square hole _5a3 is bored below into which the pipe holder 2 is inserted. On the other hand, two pole piece guide holes _5b2 are formed in the horizontal piece 5b, communicating with the V-groove _5b1 communicating with the square hole _5a3 . Further, a recess 5b ₃ is formed on the rear side surface of the horizontal piece 5b, in which a claw 6c of a shield plate 6 to be described later is engaged, and a rear end extension piece 5 is formed.
At the tip of c is an engagement recess 10b ₁ of the pedestal 10, which will be described later.
An engaging convex portion _5c1 that is engaged with is formed. Furthermore, an adhesive injection groove _5b4 communicating with the pole piece guide groove _5b2 is bored in the lower surface of the horizontal portion 5b.

The first pole piece 7 is made of a magnetically permeable material, and its magnetic detection end 7a is molded on the vertical piece 5a of the base 5, and a portion thereof is exposed in the square hole _5b2 . Note that a part of the magnetic detection end 7a is cut out _7a1 , and the resin constituting the base 5 gets into this part during molding, so that the pole piece 7 does not fall out. Also, the length of the first pole piece 7 is the horizontal piece 5.
It is formed to have approximately the same length as b.

The shield plate 6 is made of a highly conductive non-magnetic metal such as copper, and has peaks 6 in its longitudinal direction.
a is formed. A square hole is formed by this mountain portion 6a and a V-groove _5b1 formed in the horizontal piece 5b of the base 5, and the pipe holder 2 is inserted into this square hole. Note that the ridge 6a is formed with a protrusion _6a1 that protrudes toward the square hole side, which elastically presses against the pipe holder 2 when the pipe holder 2 is inserted, and firmly secures the pipe holder 2. This is to maintain good contact between the two. Further, the front end of the peak portion 6a is extended and folded back to form a bent piece 6b, and the bent piece 6b has a small hole _6b1 into which the first pole piece 7 is inserted. Furthermore, downwardly bent claws 6c are formed on both rear sides of the shield plate 6, and these are engaged with the recesses _5b3 of the base 5.

The coil 8 is wound around a bobbin 8a, and the bobbin 8a is formed in a size such that the first pole piece 7 and a second pole piece 9 described later are inserted therein.

The second pole piece 9 is made of a magnetically permeable material and has a U-shape. One side 9a of each second pole piece 9 is inserted into the bobbin 8a, and the other side 9b is inserted into the pole piece guide groove 5 of the base 5.
b Inserted into ₂ .

Next, the structure of the pedestal 10 will be described. It is composed of a receiving part 10a, a lid part 10b, and a thin connecting part 10c. A notch 10a 1 is formed at the front end of the receiving portion 10a, and a notch 10a ₁ is formed in which the projecting piece 5a ₁ of the vertical piece 5a of the base 5 is engaged, and a horizontal piece 10a ₂ located above the coil 8, and the horizontal portion 10a are formed at the front end of the receiving portion 10a. Hanging portions 10 hanging on _both rear sides of coil 8 and facing the rear end of coil 8
a ₃ and a separation piece 10a ₄ that hangs down at the rear center of the hanging portion 10a ₃ . Also, the lid part 10
Four terminal pins 12 are implanted in b, and lead wires from the coil 8 are connected to these terminal pins 12. Moreover, the base 5 is attached to this lid portion 10b.
An engagement recess 10b ₁ is formed in which the engagement protrusion 5c ₁ formed on the extension piece 5c is engaged. Note that when this lid portion 10b is bent from the connecting portion 10c,
The rear of the terminal pin 12 is located at the rear of the hanging portion 10a ₃ , that is, on both sides of the separation piece 10b ₄ .

The shield case 11 is made of a magnetically permeable material and is used to prevent magnetism from the outside, and is open at the rear, through which the pick-up device and the pedestal 10 are assembled and clothes are inserted. It's getting old. The base 5 is mounted on the front plate 11b.
A hole 11b ₁ into which the guide protrusion 5a ₂ formed on the protruding piece 5a ₁ is inserted and a square hole 11b ₂ that matches the square hole 5a ₃ of the base 5 are bored.

Next, a method of assembling each component of the above structure will be explained.

First, the small holes 6b1 bored in the bent pieces 6b of the shield plate 6 are fitted into each of the first pole pieces 7 molded and fixed to the base 5, and the claws _6c are engaged with the recesses _5b3 of the base 5. Then, the shield plate 6 is placed on the horizontal piece 5b of the base 5. Next, the bobbin 8a is inserted into each of the first pole pieces 7. Next, a jig formed to the same size as _the pipe holder 2 and whose surface has _been treated to prevent the adhesion of adhesives, etc.
Insert it into the square hole formed by. In this state, while inserting the other 9b of the second pole piece 9 into the guide groove _5b2 of the base 5, the other 9a is inserted into the bobbin 8a. At this time, the second pole piece 9 is inserted so as to cross. Next, when the adhesive is injected from the adhesive injection groove _5b4 of the base 5,
The adhesive flows into the guide groove _5b2 . Therefore, the second
Since the other pole piece 9 9b is adhesively fixed within the guide groove 5b ₂ , the tip end will not protrude beyond the guide groove 5b ₂ . As a result, even if the pipe holder 2 is inserted after the jig is removed, the second pole piece 9 will not be caught, and the magnetic detection end 7a of the first pole piece 7 will be opposed to it. The distance between the tip of the second pole piece 9 and the magnetic detection end can be determined accurately.

Next, attach the protruding piece 5a ₁ of the base 5 to the notch 10 of the pedestal 10.
a ₁ and position the horizontal part 10a ₂ on the coil 8, then connect the lead wire from the coil 8 to the terminal pin 12.
solder to. After that, with the base 5 and the pedestal 10 combined, open the opening 11 of the shield case 11.
The guide protrusion 5a ₁ formed on the protruding piece 5a ₁ is inserted into the hole 11b ₁ of the front plate 11b.
As a result, the base 5 is positioned with respect to the shield case 11, and the square hole 5a ₃ of the base 5 and the square hole 11b ₂ of the shield case 11 match. Further, since the claws 6c of the shield plate 6 come into contact with the shield case 11, the shield plate 6 is grounded by grounding the shield case 11, thereby exhibiting a shielding effect. Then, resin is filled through the opening 11a (taking care not to enter the square hole) and after it is pseudo-hardened, the lid 10b of the pedestal 10 is bent at the connecting part 10c, and the base 5 is engaged. The engaging concave portion 10b ₁ of the lid portion 10b is engaged with the convex portion 5c ₁ to close the lid. The pick-up cart cartridge is now complete.

As mentioned above, this idea fixes one end of the first pole piece to the base and attaches the second pole piece to the first pole piece.
By fitting between the coil fitted to the pole piece and the pole piece insertion groove formed on the base, both pole pieces are fixed at accurate positions with respect to the base, and therefore the pipe The position relative to the holder insertion hole is accurate, allowing for good playback.
In addition, by gluing a part of the second pole piece to the base, it is securely fixed to the base and does not protrude into the pipe holder insertion hole, causing problems such as difficulty in inserting the pipe holder. It's something that doesn't exist.

[Brief explanation of the drawing]

The figures show one embodiment of the pick-up cartridge according to this invention, in which Figure 1 is an exploded perspective view, Figure 2 is a side view showing the relationship between the replacement needle and the shield case, and Figure 3 is an assembled version of Figure 1. 4th cross-sectional view after
The figure is a bottom view of the base, and FIG. 5 is a central vertical sectional view of the same. A... Replacement needle, 2... Pipe holder, 5...
Base, 6...first pole piece, 5b ₄ ...injection groove, 8...coil, 9...second pole piece.

Claims (1)

[Scope of utility model registration request] In a pick-up cartridge having a magnetic circuit parallel to the direction in which the replacement needle is inserted into the pipe holder, the vertical piece of the base formed in a substantially L shape has a pipe holder insertion hole, and the horizontal piece communicates with the pipe holder insertion hole. A first pole piece insertion groove is formed in the vertical piece of the base, and an adhesive injection groove is formed in communication with the pole piece insertion groove.
One end of the pole piece is fixed, a coil is inserted into the first pole piece, a second pole piece is inserted between the coil and the pole piece insertion groove, and an adhesive is injected from the adhesive injection groove. A pick-up cartridge comprising a magnetic circuit in which the second pole piece is fixed to the pole piece insertion groove.