JPS6012699B2 - Tape end detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape end detection device for mechanically detecting the end of a tape in a cassette tape recorder, for example, not only during recording and playback but also during fast forwarding and rewinding. The present invention relates to a tape end detection device that mechanically detects the end of a tape during recording and playback with a fast response speed and reliably.

Conventionally, automatic stop devices for tape recorders that detect the end of the tape include those that do so mechanically by detecting the tape tension at the end of tape travel, and those that do so by electrically detecting the end of tape travel. In devices that detect tape tension, since the tension detector is always in contact with the tape, there is a problem that there is dust that can damage the tape, and the end of the tape cannot be detected when the tape is running at high speed during fast forward/rewind operations. In addition, electrical detection devices use a plunger, etc., which consumes a lot of power, making them unsuitable for portable cassette tape recorders in particular. There is a demand for a tape end detection device that purely mechanically detects the end of running, and some devices have been implemented.

That is, such a tape end detection device is shown in FIGS. 1 and 2.
As shown in the figure, a reel shaft 101, which is a rotating body that is applied to a cassette tape recorder and moves to run the tape,
A rotating member 11 consisting of a clutch pulley that rotates as the reel shaft 10 rotates is provided coaxially and rotatably via a slip mechanism consisting of a spring 12. A notch 13 is formed in the rotating member 11 by partially cutting out a peripheral surface thereof, and an intermediate portion of the detecting member 14 is disposed opposite to the notch 13. This detection member 14 is provided with a detection pin 15 at one end, and is rotatably supported at the other end by a pin on a rotating lever 17 which is rotatably supported on a fixed shaft 16. . On the other hand, the detection pin 15 of the detection member 14 slides on an eccentric cam portion 21 that is eccentric with respect to the rotation center axis formed by a cam member 20' that receives rotational driving force from a flywheel 19 that rotates irrespective of tape running. Cam groove 2 so that it touches and follows
2 is coming.

Furthermore, a locking portion 23 is integrally formed on the outside of the cam groove 22 of the cam member 20 at a position at the extreme half-fold position from the rotational center axis, to which the pin 15 of the detection member 14 is locked. Further, a fishing part 24 is provided at the tip of the rotary lever 17.

This fishing portion 24 is connected to a pin 2 at one end of the switching lever 25.
A pin 2M provided on a fishing lever 27 with a fishing end connected at a tip 6 is engaged with the pin 2M. Further, the fishing lever 27 has a fishing part 29 that is connected to the flywheel 19 when the fishing lever 27 is in an operating state.
Engagement protrusions 301 integrally formed with the protrusions 301 are disposed oppositely so as to engage with each other, and a counterclockwise bias force is applied by a spring 31.

In addition, 32 is the stopper. Furthermore, the switching lever 2
5 is rotatable clockwise about a fixed shaft 33, and the other end is engaged with a protrusion 35 of a lock plate 34.

As is well known, this lock plate 34 switches and controls each operation of the tape recorder mechanism such as recording, playback, fast forwarding, rewinding, etc., and operates the operating levers 36 and 3 that drive the magnetic tape.
7... in the pressed operation state, and the locking portions 36-, . . . of the respective operating levers 36, 37
Engagement protrusions 38-, 38-2 that engage with 37-, 37- are provided.

A bias force is applied to the lock plate 34 by a spring 39 in the direction of arrow A in the figure. The secondary tape end detection device is constructed as described above, and its operation will be described next. In the tape running state, "Reel axis 1"
The rotating member 11 is rotated through the slip mechanism 12 along with the rotation of
The tape is rotated in the same direction, and the tape runs in the same manner in recording, playback, and fast-forward operation, and only the rewind operation runs in reverse.

Here, in order to explain the operation in an easy-to-understand manner, the basic operation of ending tape running by the tape end detection device will be described using FIG.

Fig. 3a shows the tape running state during recording, playback, and fast forwarding operations, and Fig. 3b shows the tape running state during rewinding operation.
4 receives the rotational force of the rotation member 11, and receives a biasing force in approximately one direction in the direction of arrow C in the figure with the pin 18 as a fulcrum.

When the detecting member 14 receives an eccentric force, the detecting pin 15 comes into sliding contact with the eccentric cam portion 21 of the cam member 20 and follows the inside of the cam groove 22 . Then the tape reaches the end and
When the tape stops running, the reel shaft 10 stops, and the rotation is transmitted to the rotating member 11 via the slip mechanism.
The detection member 14 is no longer subjected to biasing force.

Accordingly, the pin 15 of the detection member 14 is guided along the cam groove 22 formed in the cam member 2, and is moved to the extreme half position with respect to the rotation center axis, as shown in FIG. It is locked by the locking part 23.

Therefore, the detection member 14 is moved by the rotational force of the cam member 20 in the direction D, which is approximately perpendicular to the direction in which the biasing force is received in the direction of arrow C in the figure. When the detection member 14 moves, the rotation lever 17 rotates counterclockwise about the fixed shaft 16, and the blunting bar 27 is rotated against the spring 3.
1 in the clockwise direction to engage the hook portion 29 with the engagement protrusion 3 of the flywheel 19. As a result, the cutting bar 25 connected to the fishing lever 27 is rotated clockwise by the rotational force of the flywheel 19, and the locking plate 34 is moved in the direction of arrow B in FIG. 1 to operate the operating lever. 36:37 is canceled. As described above, the tape recorder can be automatically stopped by mechanically detecting the tape running stop at the end of the tape end.

However, such a secondary tape end detection device causes problems, especially in reverse type cassette tape recorders.

In other words, since the purpose of a reverse type cassette tape recorder is to perform reciprocating recording and playback, the rotational speed of the reel shaft is small at the tape running speed (constant speed) during recording and playback in both running directions. The movement of the rotating member (clutch pulley) linked to the reel shaft is small (slow).
When the vehicle is traveling in the opposite direction, the detection section no longer follows the cam member.
That is, as shown in FIGS. 3a and 3b, at a constant tape speed, the detection member 14 follows the rotational movement of the rotating member 11 when the tape is running in the normal direction in figure a, while the tape is running in the reverse direction in figure b. Rotating operation of the rotating member 11 (rotating range)
The follow-up operation of the detection member 14, that is, the response speed of the follow-up is slow, and as a result, the movement of the cam member and the detection member cannot be followed, resulting in malfunction. This simply means that in conventional rewinding operations, the rotational speed of the reel shaft is high and the rotating member linked to it has a fast response speed, so it was able to sufficiently follow the movements of the cam member and the detection section, but reverse recording, If the tape is played back at a constant speed in both forward and reverse directions, the drawbacks mentioned above arise. Especially the cassette tape is C-12
Since the rotation speed of the reel shaft is small for tapes such as clams with a large winding diameter, the response speed of the rotating member is slow and it is not possible to follow the movements of the cam member and the detection member.

The present invention has been made in view of the above-mentioned circumstances, and has a simple configuration that reliably detects the end of the tape even when the tape is running at a constant speed in both forward and reverse directions, and automatically stops or automatically stops the tape running. It is an object of the present invention to provide a tape end detection device that performs switching. An embodiment of the tape end detection device according to the present invention will be described in detail below with reference to FIGS. 4 and 5.

The present invention is applied to a reverse-type cassette tape recorder, and its gist generally relates to the conventional improvement shown in FIG. 1, and the same configurations and symbols as in FIG. Here, for convenience of explanation, the gist of the configuration and operation will be explained in detail.

That is, there are two reel shafts, which are rotating bodies that move when the tape runs, and one of the reel shafts, the first rotary body, is the tape winding reel shaft for the forward running of the tape. The second rotating body 41, which is another reel shaft, is a tape supply reel shaft for normal tape running, and is arranged at a predetermined distance from each other. Note that the first and second rotating bodies 40 and 41 are reversed when the tape runs backwards in reverse operation, and the first rotating body 40 is the tape supply reel shaft, and the second rotating body 41 is the tape winding shaft. It operates as a reel axis.

As shown in FIG. 2, the first rotating member 42 consisting of a clutch pulley that rotates in conjunction with the rotation of the first rotating body has a slip mechanism 12 consisting of a spring. It is provided so that it can be freely extended coaxially through the . Similarly, a second rotating member 43 consisting of a clutch pulley IJ that rotates in conjunction with the second rotating body 41 is coaxially rotatable via the slip mechanism 12. It is provided. The first and second rotating members 42 and 43 are both formed with notches 44 and 45 in which a portion of their circumferential surfaces are cut out.
, 45, one end portions of a substantially T-shaped main detection member 46 and a lever-shaped sub-detection member 47 are arranged to face each other. The main detection member 46 and the sub-detection unit 47 both have first and second fixing pins 48 and 49 provided on a rotating lever 17 whose intermediate portion is rotatably supported on the fixed shaft 16. are rotatably supported on the shaft, and each has a long hole 50 at the other end.
is formed, and this elongated hole 50 is connected to the first rotary lever 17.
The second fixing pin 48, 49 and a third fixing pin 51 provided therebetween are rotatably opposed to each other. A detection pin 52 is provided at the end of the main detection member 46 shown hanging down, and this detection pin 52 has the same structure as that shown in FIG. They are shown and related so that they will work.

Note that 53 and 54 are stoppers that prevent rotation of the first and second rotation members 42 and 43 during reverse rotation. In this way, the gist of the present invention is constituted by other related operating components such as a cam member related to the detection section, a fishing lever related to the rotating lever, a flywheel, a cutting bar, etc. As stated at the beginning, the operating lever switching and release mechanism has the configuration shown in FIG. 1, and its operation will be described below with reference to this structure.

In the tape running state, the first and second rotating bodies 40,
41, the first and second rotating members 42 and 43 rotate in the same direction via the slip mechanism 12, and in constant speed running (recording, playback) operation where the tape runs in the forward direction, the first and second rotating members 42 and 43 rotate in the same direction via the slip mechanism 12. The first and second rotating members 42 and 43 rotate in the direction of the arrow shown in FIG.
2 and 43 are configured to rotate in the direction of arrow Y shown in the figure.

Here, in order to explain the operation in an easy-to-understand manner, the basic operation of detecting the end of the tape upon completion of tape running will be described using FIG.

FIG. 5a shows the tape in a forward running state during recording and playback operations, and FIG. 5b shows the tape in a reverse running state. , 43, and receives an eccentric force in approximately 10,000 directions in the direction of arrow EOZ in the figure. That is, in the tape forward running state, the main detection member 46 moves the first fixing pin 48 by the rotational force of the first rotation member 42, which is the reel shaft on the tape winding side, in the arrow EO× direction in figure a. The fulcrum receives biasing force in approximately one direction in the direction of arrow Z in the figure.

When the main detection member 46 receives an eccentric force, the detection pin 52 slides into contact with the eccentric cam portion 21 of the cam member 20 and moves to follow the inside of the cam groove 22. When the tape reaches the end and stops running, the first rotating body (reel shaft) 4
0 stops, the first rotating member 42 to which the rotation is transmitted via the slip mechanism 12 also stops, and therefore the main detection section 46 is no longer subjected to biasing force. Therefore, the detection pin 52 of the main detection member 46 is guided along the cam groove 22 formed in the cam member 20', and is moved to a position at the center of rotation with respect to the central axis of rotation, as shown in FIG. It is locked by the locking part 23 on the outside. Therefore, the main detection member 46
is moved by the rotational force of the cam member 20 in the ◯ direction, which is approximately perpendicular to the direction in which the biasing force is applied in the direction of the arrow Z. When the main detection member 46 moves, the rotation lever 17 is rotated counterclockwise about the fixed shaft 16. Therefore, the next step is to rotate the copper lever 27 clockwise against the spring 31 in accordance with the operation shown in FIG.
9 into engagement with the engagement protrusion 301 of the flywheel 19. As a result, the cutting lever 25 connected to the hook lever 27 is rotated clockwise by the rotational force of the flywheel 19, moves the lock plate 34, and releases the operated operating levers 36 and 37. Incidentally, during the normal tape running operation here, the second rotating member 43 also attempts to rotate in the same direction (X direction), but the rotation is blocked by the stopper 54' and no effect is exerted on the sub-detecting member 47. It is not subject to malfunction.

On the other hand, when the tape is running in reverse, the I
Due to the rotational force of the second rotating member 43, which serves as the J-rule axis, in the direction of the arrow Y in Figure B, the sub-detecting member 47 is now subjected to a biasing force in the clockwise direction in the figure, with the second fixing pin 49 as a fulcrum. .

Then, when the sub-detecting member 47 receives an eccentric force, the main detecting member 46 connected thereto is rotated counterclockwise about the first fixing pin 48, and as a result, the same as in the normal tape running operation shown in the figure. It will be subjected to biased force in approximately one direction in the direction of arrow Z. Therefore, in the tape running state, the main detection member 4
The detection pin 52 of No. 6 slides on the eccentric cam part 21 of the cam member 20 and follows the inside of the cam groove 22, and when the tape reaches the end and tape running stops, the sub-detecting member 47 is moved in the same manner as the normal tape running operation. Due to the indirect action via The end of the tape is detected. In addition, during the tape reverse running operation, the first rotating member 42 also tries to rotate in the same Y direction, but the rotation is prevented by the stopper 53 and does not act on the main detection member 46, so that the operation is stopped. Not applicable.

In this manner, the present invention mechanically and reliably detects the end of the tape when the tape is running in both forward and reverse directions during tape constant-speed running operations during recording and playback operations, thereby solving the conventional inconveniences during reverse operation and improving the tape recorder mechanism. It can be stopped or switched automatically without malfunction.

Since the present invention detects the end of the tape on the tape winding side when the tape is fed at a constant speed in both forward and reverse directions, it is possible to suppress the wow phenomenon as much as possible against load fluctuations, and also to suppress external disturbances as much as possible. It is also possible to easily prevent the tape from winding around the capstan, pinch roller, etc. due to some trouble caused by the tape winding around the capstan, pinch roller, etc.

Of course, it will be easy to understand that the fast forward and rewind operations operate as usual.

In the above-mentioned embodiment, the present invention uses two main and sub-sensing members that are related to each other as detecting members, and the main detecting member is attached to the first rotary member that rotates in conjunction with the forward running of the tape. The secondary detection members correspond to the second rotary members that rotate in conjunction with the running, and as a result, the main detection member is deflected to detect the end of the tape, as shown in Fig. 6. It is also possible to use one detection member for both. That is, the first
An inverted L-shaped detection section 60 is disposed between the second rotation members 42 and 43, and its intermediate portion is rotatably supported on a support pin 61 provided on the rotation lever 17. A first rotating member 42 is associated with one end of the fulcrum, and a second rotating member 43 is associated with the other end, so that the detection unit 42 is connected to the fulcrum of the tape, and the detection unit 42 is associated with the second rotating member 43 at the other end. Also, it is configured to receive biasing force in substantially one direction, the Z direction shown in the figure.

The cam member (detection cam) 62 is biased inward as described above.
The so-called outer cam has a zero-sliding portion and a locking portion at an extremely half-mounted position with respect to the rotational center axis, and has an offset zero-sliding portion 63 on the outside and an extremely small one with respect to the rotational center axis on the inside. A similar operation is performed using an inner cam having locking portions 64 at radial positions. That is, whether the tape is running in the forward or reverse direction, the detection member 60 is connected to the first and second rotating members 42, 4.
3, the cam member 62 receives an eccentric force in substantially one direction in the direction of the arrow Z in the figure, and moves to follow the outer eccentric support portion 63 of the cam member 62. When the tape reaches the end and stops running, the first Since the second rotating members 42 and 43 are stopped, the detection member 60 is no longer subjected to biasing force, and the detection pin 65 is guided to the minimum radius position by the cam groove 66 and is locked in the locking portion 64. The end of the tape is detected by being moved by the rotational force of the cam member 62, which rotates independently of tape running. This embodiment is advantageous in terms of workability because the number of parts in the detection section is only one compared to the embodiment shown in FIG. Since it is constructed in this manner, the mass is heavy and it is slightly disadvantageous in terms of the effect of imparting a biasing force, but this does not pose any problem in actual operation and the same effect can be obtained.

In addition, the present invention aims to detect the end of the tape more reliably. In order to stabilize the following operation of the detection member and the cam member, the embodiment shown in FIG. 4 is modified as shown in FIG. 7 as another embodiment. In addition, if the main detection member 46 and the sub-detection member 47 are made to have substantially the same shape to maintain balance, more effects can be achieved.

Furthermore, the present invention basically includes a first rotating body that rotates in conjunction with forward running of the tape, and a first rotating body that receives rotational force from the first rotating body via a slip mechanism. a second rotating member that rotates by moving in the reverse direction of the tape; a second rotating member that receives rotational force from the second rotating member via a slip mechanism; a detecting member that is related to both of the rotating members and receives a biasing force in substantially one direction due to the rotational force of both the first and second rotating members; When the detecting member is in a state where the detecting member is eccentric in the radial direction with respect to the rotational center axis that it follows, and when the detecting member is not receiving eccentric force, the detecting member is at the extreme radius position at the eccentric portion. a cam member that rotates independently of tape feeding and has an engaging portion that is partially engaged when the cam member is engaged, and when the cam member and the detection member are engaged, the rotational force of the cam member This is a tape end detection device that operates a detection member to detect the end of the tape in both forward and reverse running.Essentially, within the scope of the above-mentioned purpose, the cam member is operated to follow this cam member when the tape is running. When the tape stops running (at the end of the tape), the relative operation structure of the detection member engaged with the engagement portion of the cam member can be modified as shown in FIG. 8 without any problem and the same effect can be obtained. can play. That is, FIG. 8a shows that the tip of the detection member 70 receives a biasing force in substantially one direction of the arrow Z direction in conjunction with the forward and reverse tape running motions, similar to the operation of the embodiment described above. The eccentric sliding saddle part 71 and the locking part 72 provided at the maximum radius position with respect to the rotation center axis are integrally formed between this U-shape, and the rotational driving force is obtained from a flywheel or the like, which is unrelated to tape running. The cam member 73 is configured to face the rotating cam member 73. The detection member 70 is disposed in engagement with an engagement portion 75 of an actuation lever 74 for operation switching. Also in this embodiment, when the tape runs, the detection member 70 receives biased force and moves to follow the cam member 73, so that the locking portion 72 of the cam member 73 locks with the upper U-shaped piece of the detection member 70. Also, when the tape stops running (at the end of the tape), the detection member 70 is no longer subjected to biasing force, so it is pushed by the cam member 73 in the opposite direction to the biasing force, and the maximum radius &
As a result, the locking portion 72 of the cam member 73 locks on the upper U-shaped piece of the detection section 70, and the operating lever 74 is moved in the direction of arrow P in the figure by this rotational force, causing the tape recorder mechanism to operate. Crop switching takes place. In addition, Figure b shows a structure in which the cam member 73 shown in Figure A is slightly modified to have an offset protrusion 76 integrally formed in a part of the circular arc at a position at the extreme half-point with respect to the rotational center axis to perform the same operation. This is what I did.

Note that the actual shape of the cam member shown in Figure B is the same as the cam shape shown in Figure A, but the eccentric sliding contact part is omitted and an eccentric part is simply provided, so it is somewhat unstable in terms of operation. It can be carried out without any problem during normal implementation. As described above, the present invention has described the basic operation related to constant speed running of the tape in both forward and reverse directions, and various embodiments related thereto that are achieved while satisfying the technical intent of the present invention. As shown in Fig. 3, it can be easily implemented outside of a normal reverse type tape recorder. In other words, Fig. 9 shows the anti-rolling type river.
Generally speaking, by pressing an operator 80 for forward running of the tape, a slide board 81 is moved via a spring S to move the magnetic head forward and also to pinch one side. The rollers 82 are pressed against the corresponding capstan shafts 83 to drive the tape in a cassette (not shown) in the forward direction. At this time, the reel shaft 84 is driven by the idler 85 being driven by the capstan 8 by operating the operator 80.
This is accomplished by moving the reel shaft 84 so as to be interposed between the flywheel 86 and the reel shaft 84 to which the reel shaft 84 is integrally attached. On the other hand, the operator 8 for running the tape in reverse
7, the slide board 81 moves and the other pinch roller 88 comes into pressure contact with the corresponding capstan shaft 89 in the same way as in the normal tape running operation, and the idler 90 integrally attaches the capstan 89. The attached flywheel 91 is interposed between the reel shaft 92 and is compressed to drive the tape in the reverse direction.

It should be noted that the locking and operation release of the operators 80 and 90 is similar to that of a normal tape recorder mechanism and will therefore be omitted here.

The essential configuration of the tape end detection of the present invention is as shown in the above-described embodiments, FIGS. This can be easily understood by applying the previous embodiment mutatis mutandis.

That is, the reel shaft 84, which acts in conjunction with the tape running when the tape is running in the forward direction, is the first rotating body, and the reel shaft 92, which acts in conjunction with the tape running when the tape is running in the reverse direction, is the second rotating body.
If the rotating body is used, it is possible to easily realize a reverse-type tape recorder having the configuration according to the gist of the present invention. As described above, the tape end detection device according to the present invention can reliably detect the end of the tape when running in both forward and reverse directions with a simple configuration, and prevents malfunctions that occur when the tape runs backwards. It can be particularly effective when applied to a reverse type tape recorder including an auto-reverse function.

Furthermore, according to the present invention, the end of the tape is detected on the tape winding side when the tape is fed at a constant speed in both forward and reverse directions, so even if there is a problem due to disturbance and the tape gets entangled with a capstan, pinch roller, etc., it can be easily detected. It can also be used to prevent winding.

Furthermore, according to the present invention, since the wow of the rotating body on the supply side has a large influence on load fluctuations, this point is taken into account, and the end of the tape is detected on the tape winding side even when the tape is running at a constant speed in both forward and reverse directions. By doing so, wow can be suppressed as much as possible and more effective in practical use. In addition,
The present invention is not limited to the embodiments described above, and can be easily applied to movie projectors and the like, and can be implemented in various ways without changing the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the operating configuration of a conventional tape end detection device, FIG. 2 is a side sectional view of a portion of the same, FIG. 3 is a plan view showing the basic operating state of the same, and FIG. 4 is the present invention. FIG. 5 is a plan view showing the operating state of the tape end detection device according to the above embodiment, FIG. 6 is a plan view showing another embodiment of the present invention, and FIG. FIG. 8 is a plan view showing a partially modified example of the tape end detection device according to the present invention, and FIG. 9 is a plan view showing a specific configuration in which the present invention is implemented in a tape recorder. FIG. 40...first rotating body, 41...second rotating body, 42.
...First rotating member, 43... Second rotating member,
17...Rotating lever, 19...Flywheel, 20...Cam member, 21...Eccentric sliding part, 23...Locking part, 25...Kirifusuma lever, 27...Fishing lever, 46...
Main detection member, 47... Toyama detection member, 48, 49,
51...first, second, and third fixing pins, 52.
...Detection pin, 53, 54...Stock/g.
Figure 2 Figure 3 Figure 8 Figure 4 Figure 5 Figure 5 Figure 6 Figure 7 Figure 9

Claims (1)

[Claims] 1. A first rotating body that rotates in conjunction with forward running of the tape, a first rotating member that receives rotational force from the first rotating body via a slip mechanism, and a first rotating member that rotates in conjunction with forward running of the tape, and a first rotating member that rotates in conjunction with forward running of the tape. a second rotary body that rotates, a second rotary member that receives rotational force from the second rotary body via a slip mechanism, and a second rotary member that is related to both the first and second rotary members; and second
A detection member that receives a biasing force in approximately one direction due to the rotational force of any of the rotating members, and a rotation center axis that the detection member follows while receiving the biasing force. An eccentric part eccentric in the radial direction and an engaging part in which the detecting member is moved to an extreme radial position at the eccentric part and a part thereof is engaged when the detecting member is not receiving any biasing force. and a cam member that rotates independently of tape feeding, and when the cam member and the detection member are engaged, the detection member is actuated by the rotational force of the cam member to detect the end of both forward and reverse running of the tape. Characteristic tape end detection device.