JPS6323796Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cassette tape recorder, and particularly to an accidental erasure prevention claw detection device for a cassette tape recorder in which each operation is performed by operating a switch.

Conventionally, in a cassette tape recorder in which each operation is performed by a so-called feather touch switch operation, the presence or absence of an accidental erasure prevention claw provided on the cassette is also detected by operating a switch using a detection lever. .

For example, as shown in FIG. 1, a detection lever 3 is located on the side of the cassette holder 2 of the tape cassette 1, and has a contact piece 3a at its tip that corresponds to the accidental erasure prevention claw 1a of the tape cassette 1. The detection lever 3 is rotated by a spring 6 whose one end is locked to the support piece 5 in a direction (clockwise in FIG. 1) so that the abutment piece 3a is always in contact with the accidental erasure prevention claw 1a. The operating element 7a of the pawl detection operation switch 7 is always brought into contact with the rear edge of the detection lever 3 by a built-in spring.

Further, the spring 6 that rotationally biases the detection lever 3 has a biasing force that overcomes the biasing force of the built-in spring of the claw detection operation switch 7, but the rotation of the detection lever 3 is regulated by the cassette holder 2, and the opening of the cassette holder 2 is prevented. At this time, the contact piece 3a is rotated overcoming the biasing force of the spring 6 so as to be separated from the cassette holder 2.

In such a structure, the operating force of the pawl detection operation switch 7, that is, the biasing force due to the built-in spring of the operating element 7a, is quite large, so naturally the biasing force of the spring 6 that rotationally biases the detection lever 3 is also large. The movement of the cassette holder 2 or the eject button that operates against the biasing force is quite heavy, and the contact piece 3a of the detection lever 3 strongly contacts the tape cassette 1, causing the tape cassette 1 to swing or tilt. This may cause problems in the running of the tape.

To eliminate this inconvenience, the stroke of the detection lever 3 can be increased. To increase this stroke, the detection lever 3 must be lengthened, and the sliding range of the actuator 7a of the pawl detection operation switch 7 must be increased. Therefore, it requires a large amount of space and cannot be used in a small tape recorder. Furthermore, in this configuration, a microswitch is used as the claw detection operation switch 7, which has the disadvantage of increasing costs.

SUMMARY OF THE INVENTION Accordingly, the present invention provides an accidental erasure prevention pawl detection device for a cassette tape recorder which overcomes the drawbacks of the prior art and is simple in construction and reliable in operation.

An embodiment of the present invention will be described below with reference to FIG. 2 and subsequent figures.

In this example, 11 is a tape cassette, and a breakable accidental erasure prevention claw 11a is provided protruding from the rear side of the tape cassette. A window hole 12a is formed at the rear of one side of the cassette holder 12 to face the accidental erasure prevention claw 11a of the tape cassette 11, and an accidental erasure prevention claw detection device 13 is installed corresponding to one side of the cassette holder 12. has been done.

This accidental erasure prevention claw detection device 13 consists of a detection lever 14 on the movable side and a base plate 15 on the fixed side.The detection lever 14 is formed in a substantially L shape, and the tip thereof faces the window hole 12a of the cassette holder 12, and the detection lever 14 is formed into a substantially L-shape. A contact piece 14a that comes into contact with the accidental erasure prevention claw 11a of the cassette 11 is provided in a protruding manner, a U-shaped bearing 14b is formed at the central bending part, and a locking piece 14c is provided upright at the rear end. has been done. On the other hand, a shaft 16 inserted into the bearing 14b of the detection lever 14 is implanted at one end of the substrate 15, with its lower end 16a protruding toward the back side, and a long hole 15a is formed near the shaft 16. A mounting piece 15b is provided upright on the other end side, and a wiring connection board 17 on which a required conductive pattern 17a is formed is fixed to this mounting piece 15b with screws 18. A linear contact 19 is tightened and fixed with a screw 20, and this linear contact 19 is attached to a conductive pattern 17a with a screw 20'.
It is electrically connected to the lead wire 21 connected by.

The substrate 15 configured in this way is connected to the chassis 22.
The lower end 16a of the shaft 16 is fitted into the through hole 23 bored in the shaft 16, and the screw 25 is screwed into the screw hole 24 of the chassis 22 through the elongated hole 15a, thereby fixing the shaft 16.
The bearing 1 of the detection lever 14 is attached to the shaft 16 of this board 15.
4b is pivotally supported by fitting and inserting a torsion coil spring 26 inside, and one end 26a of the coil spring 26 is
The end of the winding is opposed to the linear contact 19 of the wiring connection board 17, and the other end 26b is connected to the one end 26a. The mounting piece 15b of the board 15 is crossed with the
It is fixed by screws 18'. In this way, the torsion coil spring 26 is interposed between the detection lever 14 and the board 15, so that the detection lever 14
is biased so as to be rotated outwardly with respect to the substrate 15, that is, counterclockwise in FIG.
Through the tape cassette 11's accidental erasure prevention claw 11
a, and the accidental erasure prevention claw 11a is broken off, it is rotated counterclockwise, and as a result of this rotation, the locking piece 14c at the rear end comes into contact with the wiring connection board 17 of the board 15, and the coil spring is released. One end 26a of 26 is brought into contact with the linear contact 19.

That is, the detection lever 14 and the coil spring 26 shown by solid lines in FIGS. 2 and 3 show the operating state when the accidental erasure prevention claw 11a of the tape cassette 11 is broken off, and in this state, the detection lever 14 is in its normal state. The contact piece 14a enters the tape cassette 11 and is rotated counterclockwise, and one end 26a of the coil spring 26 comes into contact with the linear contact 19 and is tangential to the linear contact 19 via the conductive pattern 17a of the wiring connection board 17. The recording circuit is configured in such a way that conduction is established between the lead wire 21 and the chassis 22, which turns the switch on, and in this state, even if the record button (not shown) on the main unit is pressed, the recording state does not start. do.

On the other hand, the accidental erasure prevention claw 11a of the tape cassette 11
is present, the detection lever 14 and the coil spring 24 are in the operating state shown by the two-dot chain line, and the detection lever 14 is in the state where the abutment piece 14a is in contact with the tape cassette 1.
1 and is pressed inward (clockwise), and one end 26a of the coil spring 26 and the linear contact 19 are held slightly apart, so that the lead wire 21 and the sheath 22 is cut off, the switch turns off, and when the record button is pressed, it enters the recording state.

The above operation is performed between the detection lever 14 and the board 15, but in order to utilize the slight amount of rotation of the detection lever 14, one end of the coil spring 26
It is desirable to maintain the relative position between 6a and the linear contact 19 accurately and to a small extent.

To perform this adjustment, first attach the tape cassette 11 with the accidental erasure prevention pawl 11a to the cassette holder 12, and with the contact piece 14a of the detection lever 14 in contact with the accidental erasure prevention pawl 11a, press one end of the coil spring 26. The lower end 16a of the shaft 16 and the through hole 23 are connected to the chassis 22 with the screws 25 loosened so that the distance between the contact 26a and the linear contact 19 can be visually confirmed (0.2 to 0.3 mm). The screw 25 is rotated around the fitting part with the screw 25 as the center of rotation, and is fixed by tightening the screw 25 at a predetermined position.

Next, for confirmation, the tape cassette 11 with the accidental erasure prevention claw 11a broken off is placed in the cassette holder 12.
The detection lever 14 will be rotated counterclockwise when attached to the
One end 26 of the coil spring 26 before finishing rotating the coil spring 26
Since the contact point a and the linear contact point 19 come into contact with each other, stable operation as a switch to which a predetermined pressure (approximately 20 g) is applied by the coil spring 26 can be obtained.

Furthermore, it is best to plate the one end 26a of the coil spring 26 and the wire contact 19 with gold plating or the like to avoid corrosion and improve contact continuity, but stainless steel wire may also be used as is. It was confirmed that it is sufficiently durable for practical use. Further, in this example, the linear contact 19 is fixed to the conductive pattern 17a of the wiring connection board 17 with the screw 20, but it may also be fixed by soldering.
Instead of the contact between the one end 26a of the detection lever 14 and the linear contact 19, a contact may be made in which the rear end locking piece 14c of the detection lever 14 is brought into direct contact with the conductive pattern 17a of the wiring connection board 17.

In this example, a protrusion 27 is provided protruding near the contact piece 14a at the tip of the detection lever 14, and this protrusion 27 is inserted into the side window hole of the cassette holder 12 when the cassette holder 12 is raised and lowered. Contact piece 14 of detection lever 14 continuous from 12a
a is in sliding contact with the edge 12c of the guided guide hole 12b, and the detection lever 14 is rotated in a direction in which the contact piece 14a is separated from the side surface of the tape cassette 11.

As described above, according to the present invention, a part of the detection member of the tape cassette's accidental erasure prevention claw is used as one contact of the detection operation switch, and the other contact is arranged on the support member of the detection member, thereby preventing accidental erasure. The nail detection device can be significantly smaller than those using conventional microswitches and can be placed in a limited space, and since the detection member and switch are integrated, the detection member can make small movements. Since it is operated by force, the tape can run smoothly without any hindrance without applying a large pressing force to the tape cassette and causing the tape cassette to swing or tilt, and the support member can be adjusted in position relative to the chassis. By doing so, it is possible to accurately adjust the distance between both contacts as a detection operation switch to the required distance, and stable switch operation can be obtained, and the effect is extremely large especially when applied to a microcassette tape recorder.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of the erroneous erasure prevention claw detection device in a conventional cassette tape recorder, FIG. 2 is a plan view of the erroneous erasure prevention claw detection device in the cassette tape recorder according to the present invention, and FIG. 3 is a part of the same. FIG. 4 is a cutaway front view and an exploded perspective view. In the figure, 11 is a tape cassette, 11a is an accidental erasure prevention claw, 12 is a cassette holder, 14 is a detection lever as a detection member, 14a is an abutment piece, 14c is a locking piece, 15 is a substrate as a support member, and 15a is a detection lever. 16 is a shaft, 17 is a wiring connection board, 19 is a linear contact, 22 is a chassis, 25 is a screw, 26 is a coil spring, and 26a is one end on the contact side.

Claims (1)

[Scope of utility model registration request] A cassette tape recorder in which each operation is performed by operating a switch includes a detection member for detecting the presence or absence of an accidental erasure prevention claw on a tape cassette, and a support member that rotatably supports the detection member and is attached to the chassis side. a part of the detection member is used as one contact point as a detection operation switch, and the other contact point is formed on the support member, and the support member is attached to the chassis side so that its position can be adjusted between the two contact points. 1. An accidental erasure prevention claw detection device for a cassette tape recorder, characterized in that the interval between the two can be adjusted.