JPS6230224Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a pressure pad mechanism that provides stable head contact between the tape and the head and is designed to reduce modulation noise, externally induced noise, and the like.

Various proposals have been made to improve the head touch of the cassette pressure pad mechanism. These conventional examples will be explained with reference to the drawings.

FIG. 1 is a plan view of a conventional example, in which 1 is a half guide rib, 2 is a regulating pin, and 3 and 4 are ribs. Reference numeral 5 denotes a shield plate whose position is fixed by the half guide ribs 1 and ribs 3 and 4, and serves to reduce externally induced noise. Reference numeral 6 denotes a leaf spring consisting of a flat part 6a and a bent part 6b, which is inserted between the regulating pin 2 and the shield plate 5, and has a pad 7 made of felt or the like adhered to the surface pressed by the head. ing. A tape 8 runs on the opposite side of the regulating pin 2 where the leaf spring 6 contacts.

FIGS. 2a, b, and 3 a, b, and c are operation explanatory diagrams showing only the main parts, and 9 is a head.

Next, the operation will be explained with reference to FIGS. 1 to 3.

When the pad 7 of the pressure pad mechanism having such a structure is pressed through the tape 8, the leaf spring 6 and the pad 7 are deformed as shown in Fig. 2a, and the tape 8 comes into contact with the head 9, and recording or playback is performed. was.

In this configuration, the flat portion 6a of the leaf spring 6 is deformed,
Since the bent portion 6b engages with the shield plate 5, the flat portion 6a must be made longer than the length of the shield plate 5. As a result, due to the deformation of the leaf spring 6, the contact of the pad 7 with the head 9 may shift from the gap in the center of the head 9 and press the tape 8, as shown in Fig. 2b, or the pressing force may change. Or, the pad 7 tends to hit unevenly.

Furthermore, if the leaf spring 6 is deformed by the pressing force of the head 9 and the contact area between the pad 7 and the head 9 increases, it becomes difficult to press the tape 8 moving against the gap of the head 9 with uniform strength. , modulation noise increases.

In addition, since the leaf spring 6 is thin,
As shown in Fig. 3, there were disadvantages such as warping and deformation, and uneven head touch.

FIG. 4 is a plan view of another conventional example, in which the shield plate 5
The elastic body 10 is bonded to the elastic body 10, and the pad 7 is bonded to the surface of the elastic body 10 opposite to the surface bonded to the shield plate 5. Other symbols are the same as in FIG.

In such a configuration, the pad 7 pressed by the head moves back and forth in the direction of the arrow, so the elastic body 10 needs to have a certain thickness in order to exhibit elasticity. For this reason, when the tape 8 runs between the head and the pad 7, the elastic body 10 and the pad 7 are both elastic and deform, causing the pad 7 to shift from the gap in the center of the head and the tape If the pad 8 is pressed or the pressing force is changed, the pad 7 tends to hit unevenly.

Furthermore, when the contact area between the pad 7 and the head increases due to the deformation of the elastic body 10, it becomes difficult to press the tape 8 moving against the gap of the head with a uniform force, resulting in an increase in modulation noise. There were other drawbacks.

FIG. 5 is a plan view of still another conventional example, in which reference numeral 11 denotes a support plate, in which a hole 12 is provided, a pin 13 is inserted into this hole 12, and a stopper 1 is inserted into this pin 13.
4 is provided. A pad support plate 15 is provided on the opposite side of the pin 13 from the stopper 14, and the pad 7 is bonded to the pad support plate 15.
5, a spring 16 is installed so as to separate the two. In addition, support plate 1
1. One or both of the pad support plates 15 can be used as a shield plate. Other symbols are the same as in FIG.

In such a configuration, since the pin 13 is loosely fitted into the hole 12, the support plate 11 and the pin 13 are likely to rattle, and the pad 7 may shift from the gap in the center of the head, causing the tape 8 to slip. The pressure may change or the pressure may change.

Furthermore, if the contact area between the pad 7 and the head increases due to the backlash between the support plate 11 and the pin 13,
Since it becomes difficult to press the tape 8 moving with a uniform force against the gap of the head, there are drawbacks such as an increase in modulation noise.

This invention was developed in consideration of the above points, and provides a pressure pad mechanism for a cassette in which a shield plate to which a pad is attached moves in the pressing direction of the head. This invention will be explained below based on the drawings.

FIGS. 6a and 6b are plan views of an embodiment of this invention, in which 21 is a half guide rib, 22 is an opening provided in the half guide rib 21, and 23 is a pair of openings provided in the half guide rib 21, each perpendicular to the half guide rib 21 and parallel to each other. The rib 24 connects the shield plate to the rib 2.
3 and 23 are a pair of regulating pins that are a means for holding the parts within each other. 25 is a U-shaped shield plate made of permalloy, iron plate, etc., which has a flat part 25a and a bent part 25b.
Therefore, the bent portion 25b comes into sliding contact with the rib 23, the tip of the bent portion 25b moves within the opening 22, and the shield plate 25 can move back and forth in the direction of the arrow. 26 is a pad, 27 is a spring which is an elastic body,
The half guide rib 21 and the shield plate 25
The structure is such that the two are mounted so as to be spaced apart from each other. 28 is a tape, and 29 is a head.

Next, the operation will be explained.

When the head 29 is pressed against the pad 26 through the tape 28 as shown in FIG.
7 and retreat. At this time, the rib 23 and the bent portion 25b are in sliding contact and the guide portions of both sides are long, so that the flat portion 25a maintains a plane perpendicular to the insertion direction of the head 29, that is, the pad 26 applies a uniform pressing force to the gap of the head 29. You can retreat while giving. This state is shown in FIG. 6b.

Since the pad 26 can retreat in the pressing direction of the head 29, the tape 28 can be pressed against the head 29 with a uniform pressing force without causing uneven contact, thereby reducing modulation noise.

Furthermore, the shield plate 25 can be closer to the head 29 than conventional shield plates, and externally induced noise caused by stray magnetic fields can be reduced.

Further, the regulating pins 24, 24 also function to provide appropriate tape tension when the tape 28 runs while contacting the head 29.

An exploded perspective view of the embodiment shown in FIG. 6 is shown in FIG.

FIG. 8 is a plan view of another embodiment of this invention.
5c is means for holding the shield plate 25 on the ribs 23, 23, and is an engaging portion provided on the shield plate 25.

In this embodiment, since the engaging portion 25c engages with the half guide rib 21, the separation distance between the half guide rib 21 and the shield plate 25 can be regulated by the spring 27 similarly to the regulating pin 24 of the embodiment shown in FIG.

FIGS. 9a and 9b are plan views of still another embodiment of this invention, in which a leaf spring is used instead of a coiled spring for the spring 27 as the elastic body.

As explained above, according to the pressure pad mechanism of the cassette of this invention, the shield plate can be moved in the direction in which the head is pressed while maintaining a plane perpendicular to the direction in which the head is pressed, resulting in stable head touch and modulation noise. can be measured to reduce Furthermore, it has the advantage of reducing externally induced noise.

[Brief explanation of drawings]

Fig. 1 is a plan view of the pressure pad mechanism of a conventional cassette, Fig. 2 a, b, Fig. 3 a, b, c.
4 is a plan view of the conventional example, FIG. 5 is a plan view of another conventional example, FIGS. 6 a and b are plan views of an embodiment of the invention, and FIG. 6 is an exploded perspective view of the embodiment, FIG. 8 is a plan view of another embodiment of the invention, and FIGS. 9a and 9b are plan views of still another embodiment of the invention. In the figure, 21 is a half guide rib, 22 is an opening,
23 is a rib, 24 is a regulating pin, 25 is a shield plate, 25a is a plane part, 25b is a bent part, 25c is an engaging part, 26 is a pad, 27 is a spring, 28 is a tape, and 29 is a head.

Claims (1)

[Scope of utility model registration request] A half guide rib, a pair of mutually parallel ribs provided perpendicular to the half guide rib, a flat part and a bent part at both ends, forming a U-shape, and a flat part on the opposite side from the bent part. The shield plate includes a shield plate provided with a pad, an elastic body installed between the half guide rib and the shield plate so as to space them apart, and means for holding the shield plate within the rib, A pressure pad mechanism for a cassette, characterized in that the shield plate is configured to slide in contact with and move within the rib.