JPH0210569Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a helical scan rotary head device used in video tape recorders, etc.
In particular, a cylindrical guide drum is used and the magnetic head is brought into good contact with the magnetic tape.

Conventionally, in a helical scan type rotary head device, the magnetic tape is scanned by the magnetic head by arranging the rotation axis of the magnetic head in an upright direction and winding the magnetic tape obliquely around a guide drum. However, the height of the magnetic tape before being guided by the guide drum and the magnetic tape after being guided in the axial direction of the guide drum differs, and it is necessary to provide a step between the two. Therefore, the structure around the guide drum is more complicated than in the case without this step, which may cause a problem. By the way, in order to eliminate this level difference in the magnetic tape and realize a parallel tape path, it is best to set the rotating axis of the magnetic head at an angle and run the magnetic tape parallel to the guide drum, but as shown in Figure 1, the rotation of the magnetic head Since the locus A becomes an ellipse B when viewed from an angle, the outline of the side surface of the guide drum needs to be an ellipse B. However, such an elliptical guide drum is difficult to process and is not suitable for mass production. Furthermore, simply replacing the cylindrical guide drum with an elliptical one poses a problem because the magnetic head cannot make good contact with the magnetic tape.

In view of this, the present invention uses a cylindrical guide drum in a helical scan type rotary head device and improves the contact of the magnetic head with the magnetic tape.

An embodiment of the rotary head device of the present invention will be described below with reference to the drawings.

In FIG. 2, reference numeral 1 denotes a cylindrical guide drum, and as is well known, a space 1a is formed in this guide drum 1 for movement of a head bar 3 to which a head base 2 is fixed and rotated at the same time.

This head base 2 is fixed to a head bar 3 fixed to a motor shaft 4, and serves as a substrate on which a magnetic head 5 is mounted.

In this example, as shown in FIG. 3, a recess 2a is formed in the head base 2 for mounting the magnetic head 5 with a degree of freedom.
A stopper 2b is provided for determining the limit of the outward protrusion of the magnetic head 5. In this case, the length ₁ of the recess up to the stopper 2b is such that when the magnetic head 5 rotates and scans, even at the point where the tip of the head bar 3 is farthest from the magnetic tape 6, the force due to the spring 2c and the centrifugal force, which will be described later, will cause the magnetic head to move. 5 should be long enough to make sufficient contact with the magnetic tape 6.
Reference numeral 2c indicates a spring which biases the magnetic head 5 in the direction of arrow C with a very small force, and both ends of the spring 2c are attached to the recess 2a of the head base 2 and a predetermined position of the magnetic head 5 as shown in FIG.

Reference numeral 5a denotes a convex portion formed on the magnetic head 5 corresponding to the stopper 2b, and this convex portion 5a engages with the stopper 2b, causing the magnetic head 5 to protrude more than necessary toward the tape 6 side, so that running of the magnetic tape is not hindered. It is intended to do so. In this way, the magnetic head 5 has an appropriate degree of freedom when protruding due to the force of the spring 2c and the centrifugal force. By attaching the magnetic head 5 to the head base 2 with suspension in this manner, the contact of the magnetic head 5 with the magnetic tape 6 can be stabilized as will be described later. A head base 2 and a magnetic head 5 having the same structure are attached to the 180° opposite side of the head bar 3.

In the rotating head device of the present invention constructed as described above, when the head bar 3 is rotated by a motor (not shown), when there is no magnetic tape 6, the magnetic head is rotated as shown in FIG. 4 when viewed from the top surface of the guide drum 1. The locus of 5 becomes an ellipse 5b. Furthermore, when the magnetic tape 6 is in contact with the cylindrical guide drum 1, it is attached with an appropriate suspension, except for the part where the tip of the magnetic head does not reach the magnetic tape 6, as shown in FIG. magnetic head 5
contacts the magnetic tape 6 with appropriate pressure to helically scan the magnetic tape 6. Therefore, the farther the magnetic tape 6 is from the tip of the head bar 3, the more the magnetic head 5 is moved by the force of the spring 2c and the centrifugal force.
This allows the magnetic head 5 to stably come into contact with the magnetic tape 6 over a predetermined scanning section. As shown in FIG. 5, the magnetic head 5 can contact the magnetic tape 6 with an appropriate pressure in the recording area 6a of the magnetic tape 6.

As described above, according to the present invention, in a helical scan type rotary head device, the magnetic tape 6 is
are wound in parallel through the cylindrical guide drum 1, eliminating the step difference, simplifying the guiding mechanism for the magnetic tape near the guide drum 1, and making good contact between the magnetic head 5 and the magnetic tape 6. It has the advantage of being able to record and play back. Further, even if there is a slight processing error in the guide drum 1, since the magnetic head 5 has suspension, good recording and reproduction can be performed.

It goes without saying that the present invention is not limited to the one embodiment described above, and that various other configurations may be adopted without departing from the gist of the present invention.

[Brief explanation of the drawing]

1, 2, and 4 are diagrams for explaining the present invention, FIG. 3 is an enlarged cross-sectional view showing an example of the essential parts of the rotary head device of the present invention, and FIG. FIG. 6 is a plan view showing the embodiment, and FIG. 6 is a side view of one embodiment of the present invention. 1 is a guide drum, 2 is a head base, 2c is a spring, 3 is a head bar, and 5 is a magnetic head.

Claims (1)

[Scope of utility model registration request] A magnetic tape is wound around a cylindrical guide drum arranged perpendicularly to a reference plane from a direction perpendicular to the axis of the guide drum, and a head base to which a magnetic head is attached is provided inside the guide drum. The rotating shaft of the head bar is arranged at a predetermined inclination angle with respect to the axis of the guide drum, and the magnetic head is attached to the head base so as to be able to protrude and displace in the rotational radial direction of the rotating shaft. A rotating head device of a helical scan type, wherein an elastic member is interposed between the head base and the magnetic head to adjust the amount of protrusion displacement of the magnetic head according to rotation.