JPH0115001Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cassette sensor hole detection device used in a cassette type tape recorder or the like.

The cassette used in a cassette-type tape recorder has an accidental erasure prevention claw formed at a predetermined position on the rear side of the cassette. If you have already recorded and do not want to erase the contents, you can break this claw and remove it. The sensor hole is formed to prevent recording, that is, to prevent already recorded data from being erased. And in order to detect this sensor hole,
A switch is provided in the cassette accommodating portion of the tape recorder to turn it on and off depending on the presence or absence of a sensor hole.
The housing position of the cassette is regulated by fitting a guide hole formed in the cassette into a guide pin provided in the cassette accommodating part, but if the dimensions of the guide hole of the cassette and the rear side where the sensor hole is formed vary. , the relative position between the sensor hole and the switch may vary, causing the switch to malfunction.

FIG. 1 is an explanatory diagram of the operation of a conventional cassette sensor hole detection device, where a shows the state in normal operation and b shows the state in malfunction. In the figure, 1 is a cassette, 2 is a sensor hole formed by breaking a claw on the rear side of the cassette, 3 and 4 are lead pieces, 5 is an insulator that insulates and holds the bases of lead pieces 3 and 4, and 6 is a lead. A detection body is fixed to the tip of the piece 3, and 7 is a contact provided on the lead piece 4. When the dimensions of the cassette 1 are accurately formed, the detection body 6 enters the sensor hole 2 and the contact point 7 does not come into contact with the lead piece 3, as shown in a. Therefore, the switch made up of the lead pieces 3, 4, etc. remains off, and a state is detected that prevents erroneous erasure. In addition, as shown by the chain line, the claw 8
If there is, the detecting body 6 is pushed by the claw 8, the switch is turned on, and a state in which recording is possible is detected.

However, when the dimensions of the cassette 1 vary, as shown in FIG. Sometimes the switch turns on. In this case, even though the sensor hole 2 for erasure prevention is formed in the cassette 1, the switch is turned on and recording becomes possible, causing the content recorded in the cassette 1 to be erased. It was hot.

In order to solve this problem, an idea has been proposed in which the micro switch is operated based on the distance between the rear surface of the cassette and the sensor hole (Utility Model Application No. 51-25940). .

However, such a device has disadvantages in that the operating mechanism is very complicated, the operation becomes unstable, and the cost increases.

This invention was made in view of the above points, and its purpose is to provide a cassette sensor hole detection system that can accurately detect sensor holes for preventing accidental erasure of cassettes with a simple configuration using a small number of parts. The goal is to provide equipment.

In order to achieve such a purpose, this invention provides a first lead piece and a second lead piece that are held parallel to each other and insulated so that the contact portions at their tips touch or separate. An engaging portion that engages with the rear side of the cassette is provided at the tip of the reed piece, and the second
A detecting section to be inserted into the sensor hole is provided at the tip of the lead piece.

This invention will be explained in detail below based on the drawings.

FIG. 2 is a front view of an embodiment of the cassette sensor hole detection device according to this invention, and FIG. 3 is a plan view. In the figure, 1 is the cassette, 2 is the cassette 1
A sensor hole is formed on the rear side to prevent accidental erasure.
Similarly, 2a and 2b are sensor holes for detecting metal tape and sensor holes for detecting chrome tape. Further, 9 is a capstan hole of the cassette 1, 10 is a cassette accommodating part of a tape recorder, 11 is a support frame provided on the top side of the cassette accommodating part 10, 12 is a board provided on the bottom, and 13 is the bottom side. The guide pieces 14, 14a, 14b that support the front side of the cassette 1 provided on the support frame 1
Frame upper piece protruding forward of 1, 15, 15
Reference numerals a and 15b designate switch units fitted and fixed in the support frame 11 so as to face the positions of the sensor holes 2, 2a and 2b, respectively.

Note that 16 is the erase head and 17 is the recording (playback) head.
The head 18 is a pinch roller, which moves in the direction of the arrow in FIG. 2 and connects to the tape in the cassette 1 during recording (playback). 19 is a capstan.

Next, the structure of the switch unit which characterizes this invention will be explained in detail with reference to FIG.

In Figure 4, a is a plan view, b is a side view, and c
is a bottom view, d is a DD sectional view of a, e is a E-
It is an E sectional view. 21 is a first plate made of an elastic metal plate;
, 22 is a second lead piece made of an elastic metal plate, and 23 and 24 are lead pieces 21 and 22.
25 and 26 are terminal parts for connecting lead wires formed at the base ends of the lead pieces 21 and 22, respectively, and 27 is a lead piece. 2
a cam as an engaging portion provided at the tip of 1;
8 is a cam as a detection unit provided at the tip of the lead piece 22; 29 is a holder made of plastic that molds the bases of the lead pieces 21 and 22 and holds them insulated so that they are arranged parallel to each other;
Reference numeral 30 indicates a protrusion disposed between the lead pieces 21 and 22 and protrudes upward; 31 and 32 indicate the lead pieces 21 and 2;
Clampers 33 and 34 are grooves formed on the outer surfaces of the clampers 31 and 32 to prevent them from coming off, respectively. 35 and 36 are lead pieces 21 and 36, respectively. The lower supports are formed in a long manner so as to be in contact with the lower surfaces of 22. protrusion 30, clamper 31,
32, the lower supports 35 and 36 are made integrally with the holder 29. When no force is applied to the cams 27 and 28, the contact portions 23 and 24 are in contact and the switch is turned on. Note that the cam 28 is formed higher than the cam 27.

This switch unit 15 is supported by a frame 11.
When inserted into the mounting hole from the front (from the bottom in Figure 3), the clampers 31 and 32 are pushed inward against elasticity, and the grooves 33 and 34 are fitted into the protrusions in the mounting hole, positioning them in the front and back direction. At the same time, the switch unit 15 cannot be removed from the support frame 11.

The structure of the switch units 15a and 15b is exactly the same.

5 and 7 are side views showing the relationship between the sensor hole 2 of the cassette 1 and the switch unit 15. When attaching the switch unit 15 to the support frame, the protrusion 30 is guided by the tapered lower surface of the upper frame piece 14 and enters from the front (from the left in FIGS. The lower supports 35, 36 and the protrusion 30 are held between the frame upper piece 14 and the switch unit 15 is positioned in the vertical direction.

FIG. 5 shows an example in which the claw 8 of the cassette 1 is not bent and the sensor hole 2 is not formed, and the cassette 1 is inserted from the direction of the arrow and the guide piece 13 and the board stand 38 are inserted. When the cassette 1 is positioned and set, the cam 27 contacts the rear side of the cassette 1 and the lead piece 21 is pushed up.
The cam 28 comes into contact with the claw 8 and the lead piece 22 is pushed up. Therefore, as shown in FIG. 6, since the cam 28 is higher than the cam 27, the contact portions 23 and 24
leaves and the switch turns off.

FIG. 7 shows an example in which the sensor hole 2 is formed by folding the claw 8 of the cassette 1, and when the cassette 1 is set, the cam 27 comes into contact with the rear side of the cassette 1. The lead piece 21 is pushed up, but the cam 28 enters the sensor hole 2 and the lead piece 22 is not pushed up. Therefore, the lead piece 22 is pushed up by the lead piece 21, and the contact portions 23 and 24 come into contact, turning on the switch. The operation of the switch units 15a and 15b is exactly the same.

In this embodiment, the switch is turned off when there is no sensor hole 2, and the switch is turned on when there is, but by reversing the overlapping state of the contact portions of the lead pieces, the switch is turned off when there is no sensor hole 2. It is also possible to configure the operation in the opposite way so that the switch is turned on and turned off at other times.

Figure 9 shows switch units 15, 15a, 15.
FIG. 2 is a block circuit diagram of an example of a tape recorder using the B. In the figure, 40 is a power switch;
1 is a power transformer, 42 is a power circuit, 43 is a capstan motor, 44 is a recording plunger, 45 is a control box, 46 is a control switch block, 4
7 is a reel motor, 48 is a head plunger, 4
9 is a brake plunger; 50, 51, and 52 are recording and playback switching switches that operate in conjunction with the recording plunger 44; 53 is a recording/playback head;
4 is an erase head, 55 is a microphone amplifier, 56 is a playback amplifier, 57 is an equalizer, 58 is a bias oscillator, 59 is a bias trap, 60 is a recording amplifier, 61 is a recording equalizer, and 62 is an on/off switch for switch units 15a and 15b. Tape selector that detects tape types such as normal, metal, chrome, etc. depending on the condition, 63 is Dolby amplifier, 64
65 is a multiplex filter, 66 is a filter switch, 67 is a meter amplifier, 68 is a meter, 69 is an output volume, and 70 is a headphone amplifier.

The control box 45 enables normal recording operation when the switch unit 15 is off, but performs various controls such that when the switch unit 15 is on, playback is performed but recording is not performed.

As described above, the cassette sensor hole detection device according to this invention is low in cost due to its simple structure with only a few parts, and since the detection reference is placed on the rear side of the cassette, it has no effect on dimensional errors of the cassette. This has the excellent effect of accurately detecting the presence or absence of a claw, that is, the presence or absence of a sensor hole, without being detected.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the operation of a conventional cassette sensor hole detection device, FIG. 2 is a front view of an embodiment of the cassette sensor hole detection device according to this invention, FIG. 3 is a plan view, and in FIG. A plan view of the switch unit, b is a side view, c is a bottom view, d is a sectional view taken along line DD in a, e is a sectional view taken along line EE in a, and Figure 5 shows the cassette and switch unit without a sensor hole. FIG. 6 is a front view of the main parts, FIG. 7 is a side view showing the relation between the cassette and the switch unit when there is a sensor hole, and FIG. 8 is a front view of the main parts. FIG. 9 is a block circuit diagram of a tape recorder using a switch unit. 1... Cassette, 2, 2a, 2b... Sensor hole, 8... Claw, 15, 15a, 15b... Switch unit, 21, 22... Lead piece, 23, 2
4...Contact portion, 27, 28...Cam, 29...Holder, 30...Protrusion, 31, 32...Camper, 33, 34...Groove, 35, 36...Lower support.

Claims (1)

[Claims for Utility Model Registration] (1) A first lead piece and a second lead piece are arranged parallel to each other and have contact parts that touch or separate from each other at their tips, and whose base parts are insulated from each other. The leading end of the lead piece is provided with an engaging part that engages with the rear side of the cassette, and the leading end of the second lead piece is provided with a detecting part that is inserted into a sensor hole formed in the rear side of the cassette. A cassette sensor hole detection device in which a contact portion is brought into contact or separated depending on the presence or absence of a hole. (2) The cassette sensor hole detecting device according to claim 1, wherein the engaging portion and the detecting portion are formed by cams.