JPS624950Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pad device for a cassette tape that supports the contact force of a magnetic head against the magnetic tape from the back side of the magnetic tape, and particularly relates to a pad device for a cassette tape that supports the magnetic tape's signal recording and playback characteristics. This prevents deterioration of the magnetic tape and effectively avoids damage to the magnetic tape.

For example, in a so-called Philips type cassette tape and other types of cassette tapes, a pad device is disposed via the magnetic tape at a portion that contacts the magnetic head of a tape recorder.

FIG. 1 shows a conventional example of the above-mentioned Phillips type cassette tape, and is a plan view with the upper half of the cassette tape removed. In FIG. 1, reel hubs 2a and 2b for supply and winding, which are engaged with the reel drive shaft of a tape recorder and driven to rotate, are rotatably mounted at symmetrical positions in the center of the lower half 1. It is being
Each end of a magnetic tape 3 is clamped to these reel hubs 2a, 2b and wound in opposite directions, and the magnetic tape 3 disposed between these reels 2a, 2b is 3 is
It is guided through guide rollers 4a and 4b provided near the left and right corners of the half 1 so as to face opening windows 5, 6, and 7 for insertion of magnetic heads (including erasing heads). Here, the magnetic head 8 for recording and reproducing signals is inserted toward the inside of the half 1 (in the direction of arrow A) from the central opening window 6. A pad device consisting of a pad member 10 attached to a leaf spring 9 is disposed on the back side of the magnetic tape 3 of this opening window 6, and when the magnetic head 8 is inserted in the direction of arrow A, the magnetic tape By supporting the magnetic head 3 from the back side, the contact force between the magnetic head 8 and the magnetic tape 3 is increased, and the efficiency of recording and reproducing signals is increased. This is because, without the above-mentioned pad device, the magnetic head 8 would be damaged while the magnetic tape 3 is running.
This is clear from the fact that the magnetic tape 3 is temporarily slightly separated from the surface of the magnetic tape 3, and the signal recording/reproducing efficiency is greatly reduced.

However, in the case of such a conventional padding device, since the surface of the pad member 10 is always in sliding contact with the back surface of the magnetic tape 3 (during tape running), the tape tension is reduced due to the frictional effect caused by this sliding. becomes large, and adverse effects such as damage to the magnetic tape 3 and torque loss of the motor are likely to occur. Also,
Since minute mechanical vibrations occur during sliding contact, there is a drawback that modulation noise and the like are mixed into the signal. Furthermore, due to the charging phenomenon caused by friction,
It also has the drawback that dust and the like tend to adhere to it, and characteristics such as the S/N ratio deteriorate due to the influence of electric charge.

The present invention was developed to eliminate these conventional drawbacks, and improves electromagnetic conversion characteristics by avoiding sliding between the magnetic tape and the pad member, and prevents negative effects such as damage to the magnetic tape. It is an object of the present invention to provide a padding device for a cassette tape that can prevent such problems.

Preferred embodiments of the present invention will be described below with reference to the drawings.

2 and 3 show a first embodiment of the present invention, FIG. 2 being a perspective view with the upper half removed, and FIG. 3 being a sectional view of the main parts of the embodiment. First, in FIG. 2, at a symmetrical position approximately in the center of the lower half 11d, reel hubs 12a and 12b for supply and winding are rotatably engaged with the reel drive shaft of the tape recorder and driven to rotate. It is located in These reel hubs 12
The magnetic tape 13 wound around the magnetic tapes a and 12b is guided to the magnetic head 18 via guide rollers 14a and 14b provided near both the left and right joints of the lower half 11d.
It is guided so as to face opening windows 15, 16, and 17 for inserting an erase head (not shown). A magnetic head 18 for recording and reproducing signals is inserted in the direction of arrow A through the central opening window 16 and comes into contact with the surface of the magnetic tape 13. On the back side of the magnetic tape 13 at the position of this opening window 16, there is a rotary pad 20.
A pad device 25 is provided.

As shown in FIG. 3, this rotary pad 20 has a flexible member 21 made of felt or rubber on its outer periphery, and has a magnetic shielding effect inside the flexible member 21. It has a concentric double structure in which a high magnetic permeability member 22 having a structure is arranged. Further, the width t of the outer peripheral surface of the flexible member 21 is set to be less than or equal to the width w of the magnetic tape 13 (t≦w). A shaft 23 passing through the center of the rotary pad 20 is rotatably supported by thrust bearing portions 24d and 24u of the upper and lower halves 11d and 11u, forming a pad device 25.

When the magnetic head 18 is inserted in the direction of arrow A through the opening window 16 in the center of the cassette half, the tip of the magnetic head 18 comes into contact with the surface of the magnetic tape 13, and the back surface of the magnetic tape 13 where the magnetic head 18 has come into contact comes into contact with the outer circumferential surface of the flexible member 21 of the rotating pad 20, so that the magnetic tape 13 is clamped between the magnetic head 18 and the rotating pad 20. When the magnetic tape 13 is driven to run, the rotating pad 2 follows suit.
The pad rotates to help the tape travel. At this time, there is no sliding between the tape and the pad as in the conventional method.

According to the pad device 25 according to the present invention, the outer circumferential surface of the flexible member 21 of the rotary pad 20 rotates following the running of the magnetic tape 13 while contacting the back surface of the magnetic tape 13, so that it is different from the conventional pad device. This eliminates sliding or slipping and reduces friction. Therefore, damage and wear on the back surface of the magnetic tape 13 can be prevented, and torque loss of the drive motor can be prevented without increasing tape tension due to friction. Further, since no charging occurs due to friction, there is no adhesion of dust, etc., and adverse effects such as signal deterioration due to charged charges are prevented. Furthermore, it goes without saying that minute mechanical vibrations caused by slippage during sliding contact can be effectively prevented. Furthermore, rotating pad 2
The axial width t of the outer peripheral surface of the flexible member 21 of
Since the width is set to be less than or equal to the width w of the magnetic tape 13 (t≦w), the magnetic head 18 and the outer circumferential surface of the flexible member 21 of the rotary pad 20 do not come into direct contact with each other, and are always connected via the magnetic tape 13. Since the rotating pad 20 makes indirect contact with the rotating pad 20, the rotating pad 20 rotates smoothly.

Next, FIG. 4 is a perspective view showing the main parts of a second embodiment of the present invention, and since the cassette half, reel hub, etc. are the same as those of the first embodiment, they are not shown and their explanation will be omitted. The pad device 35 of this second embodiment supports the rotary pad 30 by a spring member 33, and also has a guide groove 3 in the cassette half 24.
4 is formed to guide the end of the cylindrical high magnetic permeability member 32 of the rotary pad 30. Spring member 33
rotatably supports a high magnetic permeability member 32 of the rotary pad 30, and the end of this spring member 33 is supported by a pin 36 implanted in the cassette half 24. In the rotating pad 30, a cylindrical high magnetic permeability member 32 is directly used as a rotating shaft, and a soft flexible member 31 such as felt or rubber is formed around the high magnetic permeability member 32 to cover it. . The axial width t of the outer peripheral surface of the flexible member 31 is less than or equal to the width w of the magnetic tape 13 (t≦w).

When the magnetic head 18 is inserted in the direction of arrow A,
The rotating pad 30 is pressed through the magnetic tape 13, and the spring member 33 is elastically deformed, so that the magnetic tape 1
3 is held between the rotating pad 30 and the magnetic head 18 with a constant force. Further, when the magnetic tape 13 is driven to run, the rotary pad 30 rotates accordingly, so that the running of the magnetic tape 13 is not obstructed. That is, sliding as in the conventional case does not occur, and similar to the first embodiment, effects such as reducing damage to the magnetic tape 13 and torque loss of the motor, and preventing charging can be obtained.

It should be noted that the present invention is not limited to the above-mentioned embodiment, but can be easily applied to various types of cassette tapes other than the Phillips type cassette tape. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional cassette tape with the upper half removed. 2 and 3 show a first embodiment of the present invention,
FIG. 2 is a perspective view of a cassette tape to which this embodiment is applied, with the upper half removed, and FIG. 3 is a sectional view of the main parts. FIG. 4 is a perspective view showing the main parts of a second embodiment of the present invention. 13... Magnetic tape, 15, 16, 17... Opening window, 18... Magnetic head, 20, 30... Rotating pad, 21, 31... Flexible member, 22, 32
... High magnetic permeability member, 25, 35 ... Pad device.

Claims (1)

[Scope of utility model registration request] A rotary pad is provided on the back side of the magnetic tape at the position where the magnetic head is inserted in the cassette half and rotates while contacting the magnetic tape,
This rotating pad has a concentric double structure of at least an outer flexible member and an inner high magnetic permeability member that acts as a magnetic shield, and the flexible member directly contacts the magnetic head. A pad device for a cassette tape, characterized in that the width of the outer peripheral surface of the flexible member in the axial direction is formed to be less than the width of the magnetic tape.