JPH0355885B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an azimuth adjustment mechanism for an auto-reverse type cassette deck.

[Conventional technology]

The angle between the magnetic head and the magnetic tape (azimuth angle) affects the reproduction frequency characteristics, and there is an optimal azimuth angle. However, this is the case when the tape runs in the same direction, and in an auto-reverse type in which the same head handles forward and reverse runs, the best points for both runs generally do not match.

Figure 3 is a typical example of a conventional azimuth adjustment mechanism.
31 is a magnetic head; 32 is a head support base on which it is mounted; 33 is a head base for moving the head 31; 34 is a spacer; The head fixing screw 36 is an azimuth adjustment screw that uses a helical spring 37 instead of a fixed length spacer to adjust the height of the other end of the head support base 32. When the inclination of the support base 32 changes depending on the amount of engagement of the azimuth adjustment screw 36, the angle formed between the head 31 and the magnetic tape 38 also changes.

[Problem that the invention seeks to solve]

However, in the auto-reverse type in which the tape 38 runs not only in the forward direction F but also in the reverse direction P, the peak of the reproduction frequency characteristic level in each running direction occurs at different azimuth angles θ _F and θ _R as shown in FIG. It is common for this to occur. Therefore, conventionally, the adjustment is made to the intermediate point θ _M , which has the disadvantage that neither of the values is at the best level. (ΔL is the level difference from the peak). Moreover, finding this intermediate point requires changing the tape running, which results in extremely poor work efficiency.

The present invention attempts to improve these points.

[Means for solving problems]

The present invention provides an azimuth adjustment mechanism for an auto-reverse type cassette deck that reproduces signals from magnetic tapes running in different running directions using a common magnetic head.
A head holder on which the magnetic head is mounted, a mechanism that rotatably supports one end of the holder relative to the head mount, and two azimuth adjusters that are screwed onto the other end of the holder to define the inclination of the holder. an azimuth cam that moves the screw abutting part in conjunction with the screw and the tape running direction switching lever, and provides one of the two azimuth adjustment screws with a reference height by the screw abutting part; and a dowel provided on the lower surface of the other end side of the holder that engages with the holder ascending part and lifts the holder when the azimuth cam moves. It is.

[Effect]

Two azimuth adjustment screws that can be adjusted individually are provided, which are screwed into the head holder, and an azimuth cam is provided that moves the screw contact part in conjunction with the tape running direction switching lever. By giving a reference height to the azimuth adjustment screw (the other is unsupported), two azimuth angles can be achieved with one head, and the azimuth cam rotation where the screw contact part is not located below the azimuth adjustment screw is possible. During movement, the dowel rides on the holder rising part and the holder rises, so that wear on the screw contact part and the azimuth adjustment screw can also be prevented. This will be explained in detail below with reference to illustrated embodiments.

〔Example〕

FIG. 1 is a configuration diagram showing an embodiment of the present invention, and FIG. 2 is a detailed diagram of each part thereof. In Figure 1,
1 is a magnetic head, 2 is a head support base on which it is mounted, 3 is a head mount for moving the head 1 forward or backward, and 7 is a head support base 2 connected to screws 24, 2.
This is the head holder installed in step 5. This head holder 7 is elastically supported by the head mount 3 in the vertical direction.

That is, the left end is pressed from above by the L-shaped leaf spring 5. 23 is a screw for fixing the leaf spring 5, and 21 is a spacer. However, if the bottom surface of the holder 7 is brought into direct contact with the head mount 3, the azimuth adjustment can only be made upwards.
There is a spherical head rotation fulcrum (dowel) 22 on the lower left surface of the
, so that the holder 7 can rotate up and down centering on the left end. Therefore, this part 5, 21, 2
2 and 23 can also be realized by other pivot mechanisms.

On the other hand, the right end of the holder 7 is always pressed from above by a helical spring (head bias spring) 19. This spring 19 is supported by a screw 20 screwed into the upper part of a fixed shaft 20' fixed to the head frame 3. FIG. 2d shows this part enlarged. However, since the holder 7 has a through hole through which the fixed shaft 20' passes, the right end of the holder 7 will tend to rotate toward the head frame 3 if there is no member to support it from below. The two azimuth adjustment screws 8 and 9 and the azimuth cam 4 are used to appropriately prevent this movement and adjust the inclination of the head 1, and thus the azimuth angle.
The screws 8 and 9 are screwed into the holder 7, and their tips protrude downward. Reference numerals 10 and 11 indicate springs that lock the protruding lengths of the screws 8 and 9 to maintain the azimuth adjustment angle.

The azimuth cam 4 rotates on the head mount 3.
Its rotating shaft is the aforementioned fixed shaft 20', and the driving force is applied from the tape running direction switching lever 12. 26 is a shaft protruding from the lower surface of the cam 4 for linking with the switching lever 12. Reference numeral 15 denotes a screw contact portion that moves below the screws 8 and 9 when the cam 4 rotates. This is a part of the cam 4 that protrudes upward. The leaf spring 6 is an interposition that allows the screw contact portion 15 to easily slide below the spaced apart screws 8 and 9.

In the above configuration, the screws 8, 9 make it possible to separately adjust the azimuth in different tape running directions. That is, by rotating the screw 8 in the illustrated state, the azimuth can be adjusted in the tape running direction (rightward direction) according to the state of the switching lever 12 at this time. This adjustment may be made to bring out the peak of the reproduction frequency characteristics. Then, when the switching lever 12 is switched and the screw contact portion 15 is positioned below the screw 9, the screw 9 is adjusted so as to produce the peak of the reproduced frequency characteristic. At this time, the tape running direction is opposite to that of the screw 8. Therefore, as explained using the characteristic diagram of FIG. 4, the screws 8 and 9 are adjusted to produce the azimuth angles θ _F and θ _R , respectively. After this adjustment, the cam 4 rotates in accordance with the movement of the switching lever 12, so that regeneration is automatically performed at the best point.

The operating principle of the present invention has been described above, and the details of each part will be explained next. First, the leaf spring 6 has the shape shown in FIG. 1b, and although a portion thereof is engaged with the holder 7, it is basically in a free state. Therefore, the fixed shaft 20' also passes through the through hole of the leaf spring 6. The shaft 26 of the azimuth cam 4 passes through the long hole 27 of the head mount 3 and engages with the switching lever 12. In addition to the elongated hole 27, the head mount 3 is provided with a screw hole 28 into which the two locking holes 16, 16 and the screw 20 are screwed, as shown in FIG. 2a.

The azimuth cam 4 has a through hole 29 through which the screw 20 passes, as shown in FIGS. 2b and 2c. In addition to the above, this example has the following two structural features. 1st
is provided with a holder rising part 17 having a trapezoidal cross section higher than the screw abutting part 15, and when the cam 4 rotates when the screw abutting part 15 is not located below the screw 8 or 9, the spring 19
The force is absorbed by the holder rising part 17, and the screw contact part 1
5 and screw 8 or 9 from wear. In order to make this effect more noticeable, a dowel 18 is also made to protrude downward from the holder 7. That is,
When the cam 4 rotates, the dowel 18 moves to the holder rising part 17.
The holder 7 rides up and rises. As the screws 8 and 9 also rise accordingly, the contact between the screws 8 or 9 and the plate spring 6 is lost, and the screw contact portion 1
The pressing force of the leaf spring 6 against the plate spring 5 is also weakened. Eventually,
When the cam 4 rotates to a predetermined position, the dowel 8 is removed from the holder rising portion 17 and the holder 7 is lowered.
As the screws 8 and 9 also descend accordingly, the screws 8 or 9 come into contact with the leaf spring 6 while facing the screw contact portion 15. In this way, when the cam 4 rotates, the lower ends of the screws 8 and 9 do not come into contact with anything, and the pressing force of the leaf spring 6 against the screw contact portion 15 is also weakened, so that the screw contact portion 15 and the screw 8 or 9 are not in contact with each other. can prevent wear. The second is
In order to protect the state in which the screw contact portion 15 is located below the screw 8 or 9 from overstroke or vibration of the switching lever 12, the cam stop pin (or bearing) 13, which receives the downward elastic force of the spring 14, is placed in a vertically long position. The pin 13 is housed in the cylindrical portion 30, and the tip of the pin 13 is engaged with either of the locking holes 16, 16 of the head frame 3 shown in FIG. 2a. However, the head of the pin 13 is hemispherical, and its diameter is larger than the hole 16.

〔Effect of the invention〕

As described above, according to the present invention, the azimuth angle of an auto-reverse type cassette deck can be adjusted to the best point in any direction of travel, making it possible to make maximum use of the playback frequency characteristics of the heads, and making individual adjustments possible. It has the advantage of good workability. Further, when the azimuth cam is rotated so that the screw contact portion is not located below the azimuth adjustment screw, the dowel rides on the holder rising portion and the holder rises, so that wear of the screw contact portion and the azimuth adjustment screw can be prevented.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
3 is a structural diagram of a conventional azimuth adjustment mechanism, and FIG. 4 is an explanatory diagram of reproduction frequency characteristics and azimuth angle of an auto-reverse type cassette deck. In the figure, 1 is a magnetic head, 3 is a head mount, 4 is an azimuth cam, 6 is a leaf spring, 7 is a head holder,
Reference numerals 5, 21 to 23 are mechanisms for rotatably supporting one end of the holder 7, 8 and 9 are azimuth adjustment screws, 19 is a holder pressing spring, 12 is a tape running direction switching lever, and 15 is a screw contact portion.

Claims (1)

[Claims] 1. In an azimuth adjustment mechanism for an auto-reverse type cassette deck that reproduces signals from magnetic tapes running in different running directions using a common magnetic head, a head holder on which the magnetic head is mounted and one end of the holder are connected to the head mount. A mechanism for rotatably supporting the
two azimuth adjustment screws that are screwed onto the other end of the holder to define the inclination of the holder, and a screw contact portion that moves in conjunction with a tape running direction switching lever;
an azimuth cam that provides one of the two azimuth adjustment screws with a reference height by the screw contact portion; a holder lifting portion provided protruding from the upper surface of the azimuth cam; and a holder rising portion provided on the lower surface of the other end side of the holder. An azimuth adjustment mechanism comprising: a dowel that engages with the holder lifting portion and lifts the holder when the azimuth cam moves.