JPS5830655B2 - head drum sofa - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a head drum device for a VTR or the like.

For example, in a cassette type VTR, etc., the tape running loop L is formed as shown in Fig. 1 by the action of the loading mechanism and tension regulator that operate at the start, and the tape T is stabilized within this tape running loop L. Running is required.

That is, when the pinch roller 1 of the loading mechanism presses the capstan 2 by the loading operation and drives the tape at a constant speed, and the tension post 3 of the tension regulator operates, the tape T against the erasing head 4, audio head 5, and control head 6 is moved. It is relatively easy to provide stable running of the tape T for the head drum device.
Considering the functional aspects of VTRs and the like, which normally require running in diagonal directions, stable running is not easily achieved and is usually accompanied by difficulties.

To ensure stable running in the head drum device, accurate regulation of the height of the tape T in the width direction and smooth running of the tape T in the length direction are required.

Accurate regulation of the height of the tape T is carried out by a tape guide step provided obliquely on the fixed lower drum constituting the head drum device.

On the other hand, there are two types of tapes that are expected to run smoothly in the longitudinal direction of the tape T. Some have a structure in which the contact surface is stopped, and each has advantages and disadvantages.

In other words, in the case of a rotating drum whose drum-contacting surface is rotated, an air film is formed on the drum-contacting surface as it rotates at high speed, and an air film effect that allows the tape T to run smoothly can be expected. Although it has advantages such as low torque, it has disadvantages such as once the tape T sticks due to partial loss of air film or dew condensation for some reason, it is carried away and tape tangles occur. There is.

Furthermore, a stationary drum whose drum contact surface is stopped is almost the opposite of the above-mentioned rotating drum, and its unique advantage is that the drum itself has other components, such as those already proposed by the present applicant. Although it is possible to easily attach a tape presser spring, etc., which will be described later, it has the disadvantage that it is difficult to adjust the positions between the drums.

Therefore, in view of the above characteristics of the rotating drum and the fixed drum, the present invention provides an ideal head drum device for ensuring stable running of the tape T while taking advantage of the advantages of both drums.

The gist of this is that a fixed lower drum has a tape guide stepped portion diagonally disposed on its outer periphery and has a tape contacting surface of a predetermined width; a fixed upper drum has a tape contacting surface of a predetermined width;
A rotary head drum having a tape contacting surface of a predetermined width between the two drums and supporting the head chip along its outer periphery is coaxially provided.

That is, the fixed lower drum, the rotary head drum, and the fixed upper drum have a three-layer structure.

Next, an embodiment shown in FIG. 2 and subsequent figures will be described.

FIG. 2 shows the entire head drum device according to the present invention, where DU is a fixed lower drum, D□ is a rotating head drum, DT is a fixed upper drum, and a housing is provided on the lower surface of the fixed lower drum DU. 7 is fixed, for example, by a screw 8, located at the lower end of the housing 7, and fitted with a bearing adjustment nut 9.
After setting, the drum shaft 14 is rotatably supported by the lower bearing part 12 which is filled with adhesive 11 from the injection hole 10 and fixed, and the upper bearing part 13 of the fixed lower drum DU. At the lower part of the housing 7, a drum pulley 17 and a brake rotor core 18 are fixed with screws 16, and a flywheel 15 is fixed with screws 19 and 20, while the upper part of the fixed lower drum DU is fixed with screws 19 and 20. After fitting the flange member 21 into the upright portion, it is fixed with a hexagonal nut 22, and the rotary head drum DR is fixed to the flange member 21 with screws 23.

Therefore, when the power from the drive source is transmitted by the belt 24, the drum shaft 14 rotates and the rotary head drum DR is rotated.
rotates.

To control the rotation at this time, the brake coil bracket 25 is placed facing the brake rotor core 18 using a washer 26 made of synthetic resin or the like in advance.
Attachment is performed by forcefully fitting the housing 7 to prevent it from falling, by fixing it to the housing 7 with screws 27 and operating the brake coil 28.

The fixed upper drum DT is attached to the fixed lower drum DU by the coupler 30 fixed with the screw 29.
Similarly to U, it is mounted by screwing with screws 31 to support and fix while adjusting the position.

Therefore, the assembly (assembled) of each of the drums DU, DR, DT is schematically shown in FIG.
A tape contacting surface 33 of a predetermined width formed by diagonally disposing a tape guide crotch portion 32 on the outer circumferential edge of the fixed lower drum DU, and a head chip attached to the tip of the head base 34 on the outer circumferential edge of the rotating head drum D□. A tape running loop L having a three-layer structure is formed by a tape contacting surface 35 of a predetermined width facing H and a tape contacting surface 36 of a predetermined width of the fixed upper drum DT.

Next, to explain the details of each of the drums DU, D□, and DT in more detail, the fixed upper drum DT is shown in FIGS.
, an oval long hole 38 is bored in the peripheral edge of the drum symmetrical to the opening 37 in the center of the drum, and a tape guide 39, for example, a tape guide that elastically supports a tape presser spring, is provided on the upper surface of the drum. Attach holder 40 with screw 4
1, and fit the tape guide 39 into a guide groove 42 cut into a curved shape in the drum wall thickness.A wear-resistant tip 43 is attached to the tip of the tape guide 39, and a screw 44 is attached above the tip 43. The upper drum DT is covered with a cover 45 made of synthetic resin or the like and fixed to the drum DT.
The upper edge of the tape T running on the tape contacting surface 36 of the tape T is pressed and regulated.

The rotary head drum DR is shown in FIGS. 5A and 5B, and a relay printed circuit board 46 is attached to the flange member 21 at the center of the upper surface of the drum. Lead wire 4 from 34
7 and lead wires 48a of the coils 48 and 49 of the rotary transformer TR.

49a is connected.

The wiring portion of the lead wire 47 is connected to the upper surface of the rotating head drum DR which rotates at high speed, and the upper drum D is fixed above the rotating head drum DR.
Since the fixed upper drum DT is provided with the guide groove 42 of the tape guide 39 as described above, there is no space available at all.

Therefore, as shown in FIGS. 6A and 6B, the lead wire 47
There is a large chamfered portion 5 above the connecting hole 50 through which the
It is desirable to provide 0a.

The rotary transformer TR shown in FIG. 5B above is as clear in relation to FIG. 7 showing the fixed lower drum DU.
During recording or playback, electrical connection between the head chip H and the external circuit is made between the rotating head drum DR and the fixed lower drum D.
As shown in FIG. 8, a trivet-shaped rotary transformer adjusting plate 51 having an elastic standing leg piece 51a is attached to the lower surface of the flange member 21 of the rotary head drum DR. is fixed with screws 52, and a ferrite disk 53 with coils 48 and 49 concentrically wound around the center of the adjustment plate 51 is attached, while a pedestal member 54 is attached to the inner surface of the fixed lower drum DU. is fixed with screws 55, and a ferrite disk 56 is attached to the base member 54, on which coils 48', 49' corresponding to the coils 48, 49 on the rotary head drum DR side are wound.

Therefore, by raising and lowering the adjusting screw 57 screwed onto the flange member 21, the rotary transformer TR operates optimally in both coils 48:48'.

49: 49' interval, for example, ferrite disk 53
It can be adjusted by lowering from position X1 to position X2.

In this case, it is convenient to use because the adjustment can be made directly from the outside through the opening 37 of the fixed upper drum DT.

Further, the head base 34 has a distal end extending portion 34a located in a notch 58a of a skirt portion 58 raised below the peripheral edge of the rotary head drum DR, and is fixed to one surface of the drum DR with screws 59. Rotating head drum D
R is provided with an acid screw hole 60 penetrating to the head base 34 side and a head adjustment through hole 61 symmetrical to the acid screw hole 60, and each of these acid screw holes 60 and through hole 6
1 is the elongated hole 3 of the fixed upper drum DT as shown in FIG.
8 and at a position where the through hole 61 is partially blocked by the outer wall surface 34b of the head base 34.

Therefore, the head adjustment implant screw 6 is inserted into the acid screw hole 60.
2 is screwed on and raised and lowered, the height position of the head chip H can be changed from, for example, position ¥1 to Y, as shown in FIG.
It can be adjusted by lowering it to 2.

In addition, the head adjustment through hole 61 of the rotating head drum D□
A predetermined jig, for example, an elliptical eccentric jig, which passes through the elongated hole 38 formed as a through hole as shown in the figure of the fixed upper drum DT, is inserted from the opposite side facing Kazume with the head chip H attached. If the outer wall surface 34b of the head base 34 is pressed by inserting it into the through hole 61 and rotating it, the entire head base 34 moves laterally, so that the lateral position of the head chip H can be adjusted. .

In this case, it is convenient to use because adjustment can be made directly from the outside via the elongated hole 38 of the fixed upper drum DT.

The above head chip H is at an angle of 18 to the rotating head drum D□.
There are two head chips with 00, and these two head chips H
The switching operation is detected by a magnet 64 fixed to a support member 63 installed on the rotating head drum D□ and a fixed lower drum DU.
This is done by the PG coil 65 arranged on the inner surface of the
It is connected to an external electric circuit via a relay printed circuit board 68 fixed to the inner surface of the fixed lower drum DU with mounting screws 67.

Here, in order to correct the weight deviation of the rotary head drum DFL as a rotating body due to the provision of the support member 63 and the magnet 64, it is desirable to provide a balancer 69 in a balanced manner.

Further, as described above, since the skirt portion 58 is provided on the rotary head drum DR and the distal end extension portion 34a of the head base 34 is positioned in the notch portion 58a of the skirt portion 58, as shown in FIGS. 15A and 15B, rotating head drum DF
The adjoining gap g between L and the fixed lower drum DU can be kept as small as possible, for example, when the rotary head drum IyR and the fixed lower drum without a skirt part, as shown in FIGS. Distortion of the tape T' due to a large gap between the tape T' and the drum D'o can be prevented.

As shown in FIG.
The rotating head drum D slides into approximately 120°
R and fixed lower drum DT by approximately 180°.

In the case of the head drum device of the present invention, sliding contact is made approximately 4 degrees forward or approximately 4 degrees rearward on the tape inlet side and tape outlet side, respectively.

As is clear from the above, according to the present invention, the head drum D is controlled by the fixed lower drum DU, the rotary head drum DR, and the fixed upper drum DT. Accurate regulation of the height in the width direction of the tape guide stepped portion 3 of the fixed lower drum DU
2 and the fixed upper drum DT, and the tape guide 39 of the fixed upper drum DT, smooth running in the longitudinal direction of the tape T is achieved by maintaining the advantages of the fixed upper and lower drums DT and DU and the rotating head drum DR, respectively. Therefore, an extremely excellent head drum device can be provided.

In particular, according to the present invention, even after the fixed lower drum DU, rotary head drum DR, and fixed upper drum DT are integrated, the position of the head chip H can be adjusted using a jig, so that the above-mentioned The above adjustments can be easily made during the assembly process of each drum DU and DR2DT, and after assembly is completed.
Proper installation of the head chip H can always ensure its position.

Incidentally, the above-mentioned head drum device is a cassette type V.
It goes without saying that the present invention is not limited to TR, but can be applied to head drum devices of other magnetic recording and reproducing devices as long as the technical gist is not changed.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing a tape running loop in a cassette type VTR, Fig. 2 and the following shows an embodiment of the present invention, Fig. 2 is a longitudinal sectional view, and Fig. 3 shows each drum. 4A and 4B are plan views showing the upper and lower surfaces of the fixed upper drum; 5A and 5B are plan views showing the upper and lower surfaces of the rotating head drum; Figures 6A and B are partially cutaway plan views and vertical sectional views showing the assembly of the fixed upper drum and rotary head drum, Figure 7 is a plan view of the fixed lower drum, and Figure 8 is a diagram of the rotary transformer. Figure 9 is an exploded perspective view, Figure 9 is a plan view of the adjusting plate of the rotary transformer, Figure 10 is a schematic vertical sectional view showing the assembled state of the rotary transformer, Figure 11 is the head base of the fixed upper drum and the rotating head drum. FIG. 12 is an exploded perspective view showing the mounting position of the base; FIG. 12 is a partially cutaway longitudinal sectional view showing the assembled state of the fixed upper drum and rotary head drum shown in FIG. 11; FIG. 13 is the same as shown in FIG. FIG. 14 is a partially cutaway perspective view of the rotary head drum, and FIGS. 15A and B are partially cutaway side surfaces showing the state of sliding contact of the tape at the attachment part of the head base. Figures 16A and 16B are partially cutaway side views and longitudinal sectional views showing the state of tape sliding in the mounting area of a conventional head base, and Figure 17 is a tape pair of each drum. FIG. 2 is a conceptual diagram showing an expanded contact surface. DU...Fixed lower drum, 32...Tape guide stepped portion of fixed lower drum DU, 33...Tape contact surface of fixed lower drum DU, DR... ... Rotating head drum, 34... Head base of rotating head drum DR, H... Head chip, 35...
...Tape contact surface of rotating head drum D□, DT...
... Fixed upper drum, 36 ... Tape contact surface of fixed upper drum DT, 39 ... Fixed upper drum DT
tape guide.

Claims (1)

[Claims] 1. A fixed lower drum having a tape-contacting surface of a predetermined width with a tape guide stepped section disposed obliquely on the outer peripheral edge, a fixed upper drum having a tape-contacting surface of a predetermined width, and a tape of a predetermined width between the two drums. A head drum device comprising a rotating head drum coaxially provided with a contact surface and supporting a head chip so as to face the outer periphery, the head chip being screwed to one surface of the rotating head drum. The rotary head drum is also provided with a plurality of through holes for adjusting the position of the head chip from the opposite surface facing the - surface, and the fixed upper drum is provided with a plurality of through holes corresponding to the through holes of the rotary head drum. A hole having a size that includes the plurality of through holes is provided at a radial position, and the position of the head chip can be adjusted by a predetermined jig that passes through the through hole of the rotary head drum and the hole of the fixed upper drum. A head drum device characterized by: