JPH0240571Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a magnetic head rotation device for a reverse type tape recorder, which is equipped with a forward/reverse switching mechanism that switches the tape between forward and reverse constant speed running states. It is related to.

(Prior Art) In a reverse type tape recorder, since the tracks of the tape to be recorded and played back are different between the forward recording and playback mode and the reverse recording and playback mode, it is necessary to switch the magnetic head. In this magnetic head switching method, a magnetic head having a core for all the tracks (for example, 4 tracks for a stereo cassette type) used for reciprocating recording and playback is fixed, and the core is electrically switched between forward and reverse. Switching method and tracks required for one-sided recording playback (e.g. 2 tracks)
There are two methods: a method in which a magnetic head having cores corresponding to the number of tracks required for one side of the track is shifted vertically, and a method in which a magnetic head having cores corresponding to the number of tracks required for recording and reproducing one side is reversed vertically.

However, the method described above is disadvantageous in terms of cost because many cores must be incorporated into one head, and it is difficult to match the characteristics of all cores, so it is difficult to It is not suitable for high-grade tape recorders that require uniform characteristics during reverse and reverse operations. Furthermore, in the above method, the drive mechanism and positioning mechanism for shifting the head up and down are complicated, and
In a cassette tape recorder, the core must be electrically switched between the left and right channels in forward recording and playback mode and reverse recording and playback mode, and in this case too, the performance differs between forward and reverse, and it is still a high-quality tape recorder. Not suitable for tape recorders.

According to this method, there is no need to switch the core between the left and right channels when forwarding and reversing, so there is no inconvenience that the performance differs, and therefore it is used relatively often in high-end tape recorders. . It also has the advantage of being relatively simple mechanically.

FIG. 4 shows an example of a conventional magnetic head rotation mechanism according to the above method, in which a tubular bearing 2 is held by an appropriate holder, and the magnetic head 1 is rotated by the bearing 2. A gear 5 is held by the head storage case 4 of the rotary shaft 3 which is rotatably supported, and is fitted and fixed to the rear end of the rotary shaft 3.
By meshing the partial gear formed at the tip of the lever 6 and rotating the lever 6 around its support shaft 7, the gear 5 and the rotating shaft 3 substantially integral therewith are rotated.
The head 1 is turned upside down by rotating it 180 degrees. The one described in Japanese Utility Model Publication No. 49-24412 is one example.

In the case of the magnetic head rotation mechanism according to the above method, the azimuth angle of the head gap must be correctly adjusted to a predetermined angle at each rotational position of the magnetic head. Therefore, a positioning protrusion is provided on the member that integrally supports the magnetic head, and the azimuth angle is adjusted by bringing the positioning protrusion into contact with the tip of the adjustment screw at each rotational position of the magnetic head. . In this case, the head of the adjusting screw is held down by a leaf spring to prevent the adjusting screw from loosening during use and causing the adjusted position to go out of order. In the example described in the above-mentioned publication, the central portion of the leaf spring is fixedly attached with a screw, and the head of the azimuth adjustment screw is held down at both ends of the leaf spring. Furthermore, as described in Japanese Utility Model Publication No. 54-18181, a plate body whose inclination can be adjusted using a spherical or cylindrical protrusion protruding from the holding stand as a fulcrum is provided, and both ends of this plate body have an azimuth angle. There is also a configuration in which an adjustment screw is passed through the holder and this screw is screwed through the holder.

(Problem to be Solved by the Invention) According to the magnetic head rotating device described in the above-mentioned Japanese Utility Model Publication No. 49-24412, a leaf spring is attached with a screw to prevent the azimuth adjustment screw from loosening. Since the head of the azimuth adjustment screw is held down at both ends of the leaf spring, the number of parts increases due to the number of screws required to install the leaf spring, and the assembly process becomes troublesome. It was hot. Furthermore, according to the one described in Japanese Utility Model Publication No. 54-18181, since the plate through which the azimuth adjustment screw passes is in point contact with the protrusion of the holding base,
The plate will wobble and be unstable until the azimuth adjustment screw is passed through the plate and screwed into the holding base.
There is a problem that the mounting workability of the plate is poor, and there is also another problem that the head of the azimuth adjustment screw protrudes above the projection, resulting in an increase in the vertical dimension.

The purpose of this invention is to reduce the number of parts, simplify assembly work, and
An object of the present invention is to provide a rotating device for a magnetic head in a tape recorder that can prevent the vertical dimension from increasing.

(Means for Solving the Problems) The present invention comprises: a magnetic head mounting member that supports a magnetic head and has a positioning protrusion; a base that rotatably supports the magnetic head mounting member;
an azimuth adjustment screw provided on the base so that its tip is located on the rotation path of the positioning protrusion; a leaf spring whose center portion contacts the base and pushes the azimuth adjustment screw with both ends; and a mechanism for rotating the magnetic head mounting member, the base having a convex portion, the leaf spring having an inscribed surface along the convex portion, and the inscribed surface being attached to the convex portion. It is characterized by surface contact.

(Function) A leaf spring whose center is in contact with the base can be biased by moving both ends of the leaf spring, and the head is pressed down by the biasing force of both ends of the leaf spring. The azimuth adjustment screw is prevented from loosening.

(Embodiment) Hereinafter, an embodiment of a rotating device for a magnetic head in a tape recorder according to the present invention will be described with reference to FIGS. 1 to 3.

In FIGS. 1 to 3, the magnetic head 11
is fixed to the front end (right end in FIG. 1) of the head mounting member 13. Head mounting member 13
has a substantially circular contact portion 12 on the rear end surface. A rotating shaft 14 is integrally formed on the axis of the head 11 at the rear end side of the head mounting member 13. The rotating shaft 14 has a shaft hole 16 bored in the rising part of the head base 18 which is L-shaped when viewed from the side as shown in FIG.
It is rotatably fitted into the A circular protruding contact portion 17 is formed on the rising portion of the base 18 and is in contact with the contact portion 12 of the head mounting member 13 .
The contact portion 17 serves as a reference surface for determining the position of the magnetic head 11. The center of the circle along which the hole 16 and the contact portion 17 lie is the cassette 20 containing the tape.
It is processed to match the top and bottom center lines of the The head base 18 can move forward and backward together with the head base 15 by having its horizontal portion fixed onto the head base 15, which advances to the right in FIG. 1 in the recording/playback mode and retreats to the left in other modes. It is provided. The shaft 1 of the head mounting member 13 passes through the shaft hole 16 in the rising portion of the base 18.
A gear 19 is further press-fitted into the head 4 to prevent the head mounting member 13 from coming off. A lever 2 is attached to the base 18 so as to be rotatable about a shaft 29.
1 is supported, and a fan-shaped partial gear 30 formed at the upper end of the lever 21 meshes with the gear 19. Therefore, when the lever 21 is rotated, the gear 30 causes the gear 19 to rotate, which in turn causes the head mounting member 13 and the magnetic head 11 to rotate. A pin 31 is fixed to the lever 21, and a spring 22 is hung between the pin 31 and an angle 32 fixed to the base plate 27 of the tape recorder.
The lower arm of the lever 21 enters between the two protrusions 28, 28 of the forward/reverse switching member 23, and when the switching member 23 moves in the left-right direction in FIG. Rotate. At this time, due to the action of the thinking spring 22, when the thinking point is exceeded, the lever 21 quickly rotates and maintains its tilting position to the right or left. A flange 35 is formed at the end of the shaft 14 of the head mounting member 13, and at the shaft 14 portion between the flange 35 and the gear 19, a tip end of a leaf spring 26 whose base is fixed to the base plate 27 is formed. The prongs 36 are fitted. When the magnetic head 11 is retracted, the leaf spring 26 is in a natural state with no external force acting on it, as shown by the chain line in FIG. 3, but when the magnetic head 11 moves forward, as shown by the solid line in FIG. In this state, the leaf spring 26 is bent by the flange portion 35 of the head mounting member 13, and the elasticity of the spring 26 causes the head mounting member 13 to move backward (leftward in FIG. 1).
The abutting portion 12 of the head mounting member 13 abuts the abutting portion 17 of the head base 18 serving as a reference surface.

A positioning projection 24 is formed on the abutting portion 12 of the head mounting member 13, with a portion of the projection protruding laterally. On the other hand, a pair of azimuth adjustment screws 25, 25 are provided in an eave-like portion formed on the head base 18.
is provided. Azimuth adjustment screws 25, 25
is screwed into the base, and its tip protrudes downward from the eave-shaped portion. The tips of two azimuth adjustment screws 25, 25 are located on the rotation path of the positioning protrusion 24 of the head mounting member 13, and by bringing the protrusion 24 into contact with the tips of these screws 25, 25, The rotation range of the head block, in which the head 11, head mounting member 13, etc. are integrally formed, is limited to 180 degrees, and the attitude of the rotated head 11 can be adjusted to a predetermined attitude. The upper end of the head base 18 is a partially arc-shaped protrusion 81, and this partially arc-shaped protrusion 81 has a partially arc-shaped inscribed surface 38 formed at the center of the leaf spring 33. being contacted. The leaf spring 33 is used to prevent the azimuth adjustment screws 25, 25 from loosening, and both ends of the leaf spring 33 are penetrated by the azimuth adjustment screws 25, 25, and the adjustment screws 25, 25 are connected to the base 18. is screwed into. The center portion of the leaf spring 33 contacts the position of the base 18, and both ends of the leaf spring 33 are pressed down by the adjusting screws 25, 25, so that both ends are loaded with energy.
The adjustment screws 25, 25 are pushed up by the leaf spring 33 due to this accumulated force. This leaf spring 3
Each azimuth adjustment screw 25,
No. 25 locking mechanism is used to prevent loosening.

Next, the operation of the above embodiment will be explained. Assume that the recording/playback operation button is now operated. The head base 15 is moved to the position shown in FIG. 1 by a drive source such as a motor or a solenoid plunger (not shown), and the head base 18, head block, and lever 21 are also moved to move the head 11 into the cassette 20. touch the tape. Also, at this time, the elasticity of the spring 26 acts, and as described above, the contact portion 12 of the head mounting member 13 is pressed against the contact portion 17 of the head base 18, which is the positioning reference surface, thereby preventing the head 11 from wobbling. This is prevented, and the attitude of the head 11 is maintained accurately and stably, and recording and playback are performed in this state. When the tape is transported to the end in this way, the head base 15 returns to the stop position and the head 11 returns to the cassette due to this end detection signal or by inputting a manual reverse signal even while the tape is running. 20, the switching lever 23 is moved to the left in FIG. 2, and the lever 21 is rotated clockwise in FIG. As described above, the lever 21 is rotated quickly once the consideration point is exceeded by the action of the consideration spring 22, and the posture after rotation is maintained stably. Rotation of the lever 21 rotates the gear 19, and the head mounting member 13 and the head 11, which are substantially integral with the gear 19, rotate together. The rotation of this head 11 is controlled by the azimuth adjustment screw 2 as described above.
Since the angle is limited to a range of 180° by 5, the head 11 will be upside down. When the head 11 is reversed in this way, the head base 1 is turned again.
5 moves and assumes the position for recording and playback. At this time, the tape in the cassette is transported in the reverse direction, and recording and playback is performed in reverse. Also in this case, the elasticity of the spring 26 acts to press the contact portion 12 against the contact portion 17, which is the positioning reference surface, to prevent the head 11 from wobbling, and to prevent the head 11 from wobbling.
The posture of No. 1 is held accurately and stably.

According to the above embodiment, the azimuth adjustment screw 25,
Since the leaf spring 33 for preventing loosening of No. 25 is brought into contact with the base 18 at its center and the azimuth adjustment screws 25, 25 are pushed up at both ends to prevent the leaf spring 33 from loosening, the leaf spring 33 There is no need for screws or the like for attachment, which has the effect of reducing the number of parts and simplifying assembly work.

The tape recorder to which the magnetic head rotating device according to the present invention can be applied may be a reverse type tape recorder, and can be applied not only to an auto-reverse type but also to a tape recorder having a manual reverse device. Further, in the illustrated embodiment, the head base and the head base, which are made separately, are joined together, but the head base and the head base may be made as one piece from the beginning by molding or the like. .

(Effect of the invention) According to the invention, the center of the leaf spring for preventing the azimuth adjustment screw from loosening is brought into contact with the base, and both ends of the leaf spring are pressed against the azimuth adjustment screw to prevent the azimuth adjustment screw from loosening. Therefore, there is no need for screws or the like to attach the leaf spring, which has the effect of reducing the number of parts and simplifying the assembly work. In addition, since the inscribed surface of the leaf spring was brought into surface contact with the convex part formed on the base, the leaf spring would ride stably on the convex part of the base, and the leaf spring would not wobble on the convex part. This can improve assembly workability. Furthermore, since both ends of the leaf spring through which the azimuth adjustment screw passes are located at a position lower than the convex portion, the head of the screw can be located at a position lower than the convex portion. It is possible to provide a head rotation device with a small height dimension.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view showing an embodiment of a magnetic head rotating device in a tape recorder according to the present invention, FIG. 2 is a rear view of the same, and FIG. 3 is a partially simplified version of the same embodiment. The plan view and FIG. 4 are side sectional views showing an example of a rotating device for a magnetic head in a conventional tape recorder. DESCRIPTION OF SYMBOLS 11... Magnetic head, 13... Head mounting member, 18... Base, 24... Positioning protrusion, 25
...Azimuth adjustment screw, 33...Plate spring.

Claims (1)

[Claims for Utility Model Registration] A tape recorder equipped with a forward/reverse switching mechanism for switching the tape between forward and reverse constant speed running states, comprising: a magnetic head mounting member that supports a magnetic head and has a positioning protrusion; a base that rotatably supports the head mounting member and has a convex portion; an azimuth adjustment screw provided on the base so that its tip is located on the rotation path of the positioning protrusion; and a convex portion of the base. an inscribed surface along which the inscribed surface is brought into surface contact with the convex portion of the base, and a leaf spring that presses the azimuth adjustment screw at both ends; and a mechanism for rotating the magnetic head mounting member. The tape is characterized in that the magnetic head is rotatably moved to two positions corresponding to constant speed running of the tape in the forward and reverse directions, respectively, with the tape sliding surface of the magnetic head facing the tape. A rotating device for the magnetic head in a recorder.