JPH0441422B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a cassette tape recorder using a cassette tape, and more particularly to a detection device for detecting the end of a magnetic tape.

(B) Prior Art Cassette-type tape recorders that use cassette tapes, in which magnetic tape is stored in a container called a cassette, have become popular, but such cassette-type tape recorders do not operate until the magnetic tape reaches its end. It is equipped with a device called an automatic stop device that switches the state, for example, from the reproducing operation state to the stop state. Such automatic stop devices include those that detect the tension of the magnetic tape and those that detect the stoppage of rotation of the reel shaft, but recently a system that detects the stoppage of rotation of the reel shaft has become common. There are two types of methods for detecting the stoppage of rotation of the reel shaft: electrical and mechanical.However, since the electric method is expensive, popular tape recorders mechanically stop the rotation of the reel shaft. The most common method is to detect the
There is one disclosed in Publication No. -49245. In addition, some recent cassette tape recorders do not only play or record in the first direction, but also play or record in the second direction, which is the opposite direction to the first direction, in order to perform long-term playback or recording. There are things that are configured so that they can perform actions. A cassette tape recorder having such a bidirectional playback or recording function is configured to automatically reverse the running direction, but such a tape recorder must perform the reverse operation quickly. Therefore, the reversing operation is performed by detecting a leader tape provided at the end of the magnetic tape. A technique for detecting such a leader tape is disclosed, for example, in Japanese Utility Model Publication No. 19720/1983.

(C) Problems to be Solved by the Invention In a cassette-type tape recorder configured to detect the end of a magnetic tape by detecting the leader tape, when the leader tape is detected, a reversing operation or an automatic operation is performed. A stop operation is performed, but some cassette tapes are not equipped with a leader tape, and when such a cassette tape is used, the reversal operation or automatic stop operation will not be performed. Therefore, such a cassette tape recorder is generally equipped with a device for detecting the stoppage of rotation of the reel shaft in addition to a device for detecting the leader tape. The reversal operation of the running direction of the magnetic tape upon detection of the leader tape is performed using the suction force of the plunger, and the plunger used for this operation is
There are problems in that a large suction force is required and the configuration is complicated. The present invention aims to provide an end detection device that is improved in this respect.

(d) Means for Solving the Problems The end detection device of the present invention includes a rotating body that is rotationally driven regardless of the rotation of the reel shaft and is provided with an eccentric cam and a switching pressing protrusion, and a first position. a sliding member that is mounted so as to be displaceable between the first position and the second position and receives a displacement force in the first position direction when the reel shaft is in rotation; and the sliding member is displaced to the first position. The operation causes the sliding member to be displaced to a non-switching position where it does not come into contact with the switching pressing projection, and is also displaced by the eccentric cam to a switching position where it comes into contact with the switching pressing projection, and the sliding member is displaced in the first direction. A control lever is moved to an operating position by contact with the switching pressing protrusion as the force disappears, and a control lever is caused to perform a suction operation when a non-magnetic portion provided at an end of the magnetic tape is detected. and a plunger for displacing and holding the sliding member in the second position.

(E) Effect The present invention provides a plunger that causes a sliding member provided to detect rotation stoppage of a reel shaft to be operated to attract when a non-magnetic portion provided at an end of a magnetic tape is detected. Thus, the terminal end detection operation is performed by sliding displacement.

(f) Examples The drawings all relate to the termination detection device of the present invention.
Figures 1 and 2 are plan views showing different states when the reel shaft is in a rotating state, Figure 3 is a plan view showing a state where the reel shaft has stopped rotating, and Figure 4 is detection of rotation stoppage of the reel shaft. FIG. 5 is a plan view showing the state of the switching operation accompanying the operation, and FIG. 5 is a plan view showing the state in which the plunger is in suction operation. In the figure, reference numeral 1 denotes a sliding member that is attached to a fixed board so as to be able to be displaced in the directions of arrows A and B, and that receives a displacement force in the direction of arrow A when the reel shaft (not shown) is in a rotating state. It is movable between a first position shown in FIG. 1 and a second position shown in FIG. 2, and is provided with an abutting portion 2 and a switching piece 3. 4 is a drive gear that is rotated when the electric motor (not shown) is in a rotating state; 5 is a first gear that is always in mesh with the drive gear 4; and 6 is a gear that rotates integrally with the first gear 5. A second gear 7 is a rotary body which is rotatably mounted on a shaft 8 and is provided with an eccentric cam 9 and a switching pressing protrusion 10. 2 teeth 11 in mesh with gear 6
is formed. Reference numeral 12 denotes a switching lever which is normally in the non-operating position shown in Fig. 1 and is displaced to the switching operating position shown in Fig. 4 during switching operation, and is automatically stopped by the displacement force to the switching operating position. Alternatively, the running direction of the magnetic tape is reversed. 13 is the switching lever 1
2 is a control lever rotatably attached by a shaft 14 to a pressing piece 15 that is pressed by a contact portion 2 formed on the sliding member 1 and a control lever formed on the rotating body 7. A control pin 16 is formed which abuts against the eccentric cam 9 and engages with the switching pressing protrusion 10. Reference numeral 17 denotes a plunger which is supplied with power and enters a suction operation state when a non-magnetic material portion such as a leader tape provided at the end of the magnetic tape is detected; and 18 is rotatably mounted on a shaft 19. Spring 2
0, which is rotatably biased in the clockwise direction, and is rotatably displaced counterclockwise by the suction action of the plunger 17, and is a switching lever formed on the sliding member 1. It has the effect of coming into contact with the piece 3 and displacing the sliding member 1 in the direction of arrow B, which is the second position. The termination detection device of the present invention is constructed as described above, and the operation of this device will be explained next.

First, a detection operation for detecting rotation stop of the reel shaft will be explained. When the reel shaft is in a rotating state due to a reproducing operation or the like, the sliding member 1 is constantly subjected to a displacement force in the direction of arrow B. On the other hand, since the driving gear 4 is in a clockwise rotationally driven state, the rotating body 7 to which the rotation of the driving gear 4 is transmitted via the first gear 5 and the second gear 6 is rotationally driven clockwise. It turns out. When the rotating body 7 rotates clockwise, the eccentric cam 9 and the switching pressing protrusion 10 formed on the rotating body 7 also rotate clockwise. In this state, the control lever 13, which is rotatably attached to the switching lever 12, receives the force of displacement of the sliding member 1 in the direction of arrow A, and thus receives a counterclockwise rotation biasing force. in a state. Therefore, the control pin 16 formed at the other end of the control lever 13 is pressed into contact with the eccentric cam 9 formed on the rotating body 7. In the state shown in FIG. 1, the sliding member 1 is
In this state, the control pin 16 formed on the control lever 13 is in contact with the short diameter portion of the eccentric cam 9. From this state, the rotating body 7
When the eccentric cam 9 rotates clockwise, the eccentric cam 9 rotates clockwise, but since the diameter of the eccentric cam 9 gradually increases, the control lever 13 resists the pressing force received from the sliding member 1. At the same time, the sliding member 1 is moved to a second position in the direction of arrow B against the pressing force received from the reel shaft. The state shown in Figure 2 is
The control pin 16 formed on the control lever 13 is in contact with the longest diameter portion of the eccentric cam 9, and in this state, the sliding member 1 is in the most displaced state in the direction of arrow B. From this state, the rotating body 7
When the eccentric cam 9 rotates clockwise, the eccentric cam 9 rotates clockwise, but since the diameter of the eccentric cam 9 gradually becomes shorter, the control lever 13 is moved by the pressing force received from the sliding member 1. Then, it is rotated counterclockwise and becomes the state shown in FIG. When the reel shaft is in a rotating state as described above, the sliding member 1 is moved as shown in FIG. The control lever 13 is reciprocated between the first position shown in FIG. 2 and the second position shown in FIG.
is caused to reciprocate between the non-switched position shown in FIG. 1 and the switched position shown in FIG. When the reel shaft is in a rotating state, the control pin 16 formed on the control lever 13 follows the eccentric cam 9 and is displaced. It never comes into contact with. Therefore, the switching lever 12 to which the control lever 13 is rotatably attached is not moved to the switching operation position, and operations such as playback of the tape recorder continue to be performed. When the magnetic tape runs to the end in this operating state, the reel shaft stops rotating.
The pressing displacement force of the sliding member 1 in the first position direction, that is, in the direction of arrow A disappears. When the pressing displacement force of the sliding member 1 in the direction of the arrow A disappears, the sliding member 1 and the control lever 13 are at the position pressed and displaced by the longest diameter part of the eccentric cam 9, that is, the position shown in FIG. It becomes stationary at . When the rotating body 7 rotates clockwise in this state, the switching pressing protrusion 10 formed on the rotating body 7 comes into contact with the control pin 16 formed on the control lever 13, as shown in FIG. come into contact with When the rotating body 7 further rotates clockwise from this state, the switching pressing protrusion 1
0, the control pin 16, ie, the control lever 13, receives a displacement force in the direction of arrow C. As a result, the switching lever 1 to which the control lever 13 is attached
2 receives the displacement force and is displaced to the switching operation position as shown in FIG. The switching lever 12
An automatic stop operation or a reversal operation of the running direction is performed by the displacement operation to the switching operation position.

The magnetic tape end detection operation for detecting the stoppage of rotation of the reel shaft is performed as described above.Next, we will explain the end detection operation by detecting a non-magnetic part such as a leader tape provided at the end of the magnetic tape. explain. When the cassette tape recorder is in an operating state such as playback, the reel shaft is in a rotating state, so that the sliding member 1 is subjected to a displacement force in the direction of arrow A, which is the first position direction. Therefore,
The sliding member 1 and the control lever 13 are reciprocated between the position shown in FIG. 1 and the position shown in FIG. 2 by the action of an eccentric cam 9 formed on the rotary body 7. It is in. In this state, when the magnetic tape travels to the end, a non-magnetic part such as a leader tape provided at the end is detected by a detection circuit (not shown), and power is supplied to the plunger 17. Ru. Said plunger 17
When power is supplied to the plunger 17, the plunger 17 performs a suction operation, and the pivot lever 18 is pivoted counterclockwise against the biasing force of the spring 20. When the rotating lever 18 rotates counterclockwise, the protruding piece 21 formed on the rotating lever 18 comes into contact with the switching piece 3 formed on the sliding member 1, causing the sliding member 1 to move in the direction of the arrow. It is displaced to the second position in the direction of arrow B against the biasing force in the direction A and is held at that position until a switching operation is performed. When the sliding member 1 is displaced and held in the second position, the counterclockwise rotational displacement force of the control lever 13 disappears as described above, so that the control lever 13 is moved by the longest diameter part of the eccentric cam 9. It comes to a resting state at the position where it is pressed and displaced, that is, the position shown in FIG.
When the rotating body 7 rotates clockwise in this state, the switching pressing protrusion 10 formed on the rotating body 7 comes into contact with the control pin 16 formed on the control lever 13, as shown in FIG. come into contact with When the rotating body 7 further rotates clockwise from this state, the control pin 16, ie, the control lever 13, receives a displacement force in the direction of arrow C by the switching pressing protrusion 10. As a result, as described above, the control lever 1
The switching lever 12 to which the switch 3 is attached receives a displacement force and is displaced to the switching operation position shown in FIG. By moving the switching lever 12 to the switching position, an automatic stop operation or a reversal operation of the running direction is performed. After this operation is performed, the power supply to the plunger 17 is cut off. In this manner, the end detection operation in this embodiment is performed by detecting the non-magnetic material portion provided at the end of the magnetic tape.

In this embodiment, the switching lever 12, which is moved to the switching operation position by the control lever 13, is rotated, but it can also be configured to slide linearly. Further, a mechanism that performs an automatic stop operation or a mechanism that performs a reversal operation in the traveling direction by the displacement force of the switching lever 12, and a mechanism that selects and performs an automatic stop operation and a reversal operation can be constructed using well-known technology. I have omitted the explanation.

(G) Effects of the Invention The end detection device of the present invention detects the sliding member provided for detecting the stoppage of rotation of the reel shaft when a non-magnetic portion provided at the end of the magnetic tape is detected. A plunger with a suction action is used to slide and displace the reel shaft to bring it into a state similar to when it stops rotating, and this action is used to detect the end of the reel, so a plunger with a large suction force is not required. This has the advantage that not only is the structure simple, but also the structure is simple.

[Brief explanation of drawings]

The drawings all relate to the termination detection device of the present invention,
Fig. 1 is a plan view showing the state when the reel shaft is in a rotating state, Fig. 2 is a plan view showing a state different from Fig. 1 when the reel shaft is in the rotating state, and Fig. 3 is a plan view showing the state when the reel shaft is in a rotating state. A plan view showing a state where rotation has stopped,
FIG. 4 is a plan view showing a state of switching operation accompanying the rotation stop detection operation, and FIG. 5 is a plan view showing a state where the plunger is in suction operation. Explanation of main drawing numbers, 1...Sliding member, 4...Drive gear, 7...Rotating body, 9...Eccentric cam, 10...
Switching press protrusion, 12...Switching lever, 13...
...Control lever, 16...Control pin, 17...Plunger.

Claims (1)

[Claims] 1. A rotary body that is rotatably driven regardless of the rotation of the reel shaft and is provided with an eccentric cam and a switching pressing protrusion, and a rotary body that is mounted so as to be displaceable between a first position and a second position, and a reel shaft. a sliding member that receives a displacement force in a first position direction when the sliding member is in a rotating state; and the sliding member is displaced to a non-switching position where it does not come into contact with the switching pressing protrusion by the movement of the sliding member toward the first position. At the same time, it is displaced by the eccentric cam to a switching position where it comes into contact with the switching pressing projection, and as the displacement force of the sliding member in the first position direction disappears, the sliding member comes into contact with the switching pressing projection. a control lever that can be moved to an operating position;
A terminal end detection device for a cassette type tape recorder comprising a plunger which is operated to attract when a non-magnetic material portion provided at the end of a magnetic tape is detected, and which displaces and holds the sliding member at a second position.