JPH0146928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cassette tape recorder having a mechanism (hereinafter referred to as a "shut-off mechanism") for returning the magnetic tape from the playback or recording state to the stop state when the magnetic tape reaches its end during tape running. .

Conventionally, there have been mechanisms for shut-off mechanisms that electrically detect the end of the tape and use the driving force of a plunger, or detect the end of the tape by detecting an increase in tape tension and use the rotational power of the flywheel. A mechanism has been developed. There are also circuits that simply stop the motor electrically.

However, a mechanism using a plunger or the like tends to increase the size and cost of the device, and also has drawbacks such as the tendency to pick up noise when the plunger operates. Furthermore, the mechanism that relies on tape tension not only causes deterioration in sound quality but also has defects that place a large load on tape running. Also, the one that turns off the motor power had a defect in that if the pinch roller was left pressed against the capstan for a long time, the pinch roller would become deformed.

The present invention was invented in view of these points, and it mechanically detects the end of the tape and mechanically performs the shut-off operation.It is said that the structure is simple and the time required for shut-off is extremely short. This provides an ideal mechanism. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of the main parts of a micro-sized cassette tape recorder, and the state shown is in a stopped state. FIG. 2 is an explanatory view of the main parts of the shut-off mechanism, which is in a regenerating state. The position of the microcassette 8 indicated by the two-dot chain line is regulated by guide pins 9a and 9b, and the reel hubs 8b and 8c are loosely fitted to the reels 6 and 5, respectively. Motor 1 shown in broken line
is fixed to a chassis (not shown), and a motor pulley 1a is fixed to the output shaft. The capstan 4 is press-fitted into the center hole of the flywheel 3 and supported by a bearing (not shown) so as to rotate together with the flywheel. The pinch roller 14 rotates integrally with the pinch roller shaft 14b and is freely rotatably supported by one end of the pinch arm 15. The other end of the pinch arm 15 is pivoted to a fixed shaft 21b fixed to a chassis (not shown). In addition, a spring (not shown) is attached to the pinch arm 15.
The fixing pin 16 implanted in the regeneration lever 18 is attached so that it can be rotated counterclockwise.
This prevents the pinch roller 14 from coming into contact with the capstan 4.

The stop lever 17, the playback lever 18, and the recording lever 19 are supported so that they can slide in the direction of arrow A and in the opposite direction, and springs (not shown) are attached to each lever so as to elastically repel each lever in the direction opposite to arrow A. . Although the remaining fast forward levers, rewind levers, etc. are omitted, they are provided in the same way.

A magnetic head 11 and a tape guide 12 are fixed to the front side of the playback lever 18, and a lock pin 18 that engages with a lock plate 20 is fixed to the back side of the playback lever 18.
A is planted. A lock pin 17a that engages with a lock plate 20 is implanted on the back side of the stop lever 17. The lock plate 20 includes a stop lever 17,
It is arranged below the reproduction lever 18 and the recording lever 19. Further, the lock plate 20 is formed with elongated holes 20c and 20d which fit into guide pins 10a and 10b installed in a chassis (not shown). The lock plate 20 is normally pulled to the left by a spring 23. A slope 20b is formed on the lock plate 20 so that when the release pin 17a moves in the direction of arrow A, the lock plate 20 moves to the right, and when the lock pin 18a moves in the direction of arrow A, it engages with the lock pin 18a. A matching cam step portion 20a is formed as shown by the broken line.

When the regeneration lever 18 is pushed in the direction of arrow A and the lock pin 18a is locked to the cam stepped portion 20a,
The pinch roller 14 pinches the magnetic tape 8a and presses it against the capstan 4, and the magnetic head 11 pinches the magnetic tape 8a and presses the pressure pad 8b. At this time, the tip of the regeneration lever 18 engages with another lever (not shown), causing the intermediate gear 25 (second figure) to mesh with the large reel gear 5b, and the intermediate gear 25 and the capstan gear 4a. Therefore, the magnetic tape 8a fed at a constant speed by the capstan 4 and the pinch roller 14 is wound around the hub 8c without slack.

Next, when the stop lever 17 is pressed in the direction of arrow A, the release pin 17a presses the slope 20b and moves the lock plate 20 to the right against the elastic force of the spring 23, causing the lock pin 18a and the cam step 20a to move. release the engagement.

The lever 21 is rotatably mounted around a fixed shaft 21b, and a return pin 2 is attached to the lower end of the lever 21.
1a, and an intermediate gear 26 is rotatably attached to the upper end of the lever 21 about a shaft 21c. Further, a spring 24 is tensioned on the lever 21, and a rotational force acts on the lever 21 in a clockwise direction to press a fixing pin 22 installed in a chassis (not shown). During regeneration, the return pin 21a counteracts the tension of the spring 24 and acts counterclockwise on the lever 21, causing the lock plate 20 to move to the right and return the regeneration lever 18 to its spring state.

Next, a mechanism for detecting a tape end state and shutting off the tape will be explained using FIG. Components that are the same as those in FIG. 1 are expressed using the same symbols.

The capstan gear 4a rotates together with the capstan 4 and meshes with the intermediate gear 25. The intermediate gear 25 meshes with the reel large gear 5b during playback (including recording) or fast forwarding, and meshes with the intermediate gear 25a during rewinding. The reel large gear 5b and the reel small gear 5a are integrally molded, and the reel shaft 5a
The first
Torque is transmitted to the illustrated reel 5. Intermediate small gear 2
7a and the intermediate large gear 27b are integrally molded, and the fixed shaft 2
1b, and the intermediate small gear 27a is always meshed with the intermediate gear 26. The pinch roller shaft 14b is rotatably supported by the pinch arm 15 (first illustration) and rotates together with the pinch roller 14. A pinch roller gear 14a is fixed to the lower end of the pinch roller shaft 14b, and the pinch roller gear 14a meshes with the intermediate large gear 27a.

The intermediate gear 25 is rotated by the capstan gear 4a, and the large reel gear 5b is rotated by the intermediate gear 25. (referred to as first transmission) Also, the pinch roller 14 and the pinch roller gear 14a are rotated by the capstan 4, and the pinch roller gear 1
4a, the intermediate large gear 27b and the intermediate small gear 27
a, the intermediate gear 26 is rotated, and the reel small gear 5c is rotated by the intermediate gear 26. (referred to as second transmission) The reduction ratio is determined so that the rotational speed of the reel pinion 5c due to the first transmission and the rotational speed of the reel pinion 5c due to the second transmission are the same. Therefore, while the tape is running, the pinch roller 14 is subjected to two forces: the frictional force from the capstan 4 and the gear transmission force from the first and second transmissions.

When the magnetic tape 8 reaches the end and stops, the pinch roller 14 is stopped by friction with the magnetic tape 8, and the pinch roller gear 14a, intermediate large gear 27b, and intermediate gear 26 are also stopped. However, at this time, the capstan 4 continues to rotate, and the reel small gear 5c attempts to rotate. Therefore, intermediate gear 26
At the meshing portion between the reel pinion 5c and the reel pinion 5c, the teeth of the reel pinion 5c push aside the teeth of the intermediate gear 26. Therefore, the lever 21 is rotated in the direction of arrow B using the fixed shaft 21b as a fulcrum. By rotating the lever 21, the lock plate 20 is moved to the right, and the engagement between the lock pin 18a and the cam stepped portion 20a is released.

As is clear from the above description, according to the present invention, the objects stated at the beginning are achieved and the effects are significant. Although the embodiments have been explained using a micro cassette tape recorder, it goes without saying that the present invention can also be applied to a normal cassette tape recorder.

Furthermore, according to the present invention, the pinch roller 14 is not rotated only by the friction between the capstan 4 and the magnetic tape 8, but is reliably rotated by the first transmission and the second transmission, so that the magnetic tape 8 does not slip. The tape is fed at a constant speed, and tape speed deviation is also improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the main parts of an ultra-small cassette tape recorder, and FIG. 2 is an explanatory diagram of the main parts of a shut-off mechanism. 1... Motor, 2... Belt, 3... Flywheel, 4... Capstan, 5, 6... Reel, 8... Micro cassette, 9a, 9b... Guide pin, 11
... Magnetic head, 12 ... Tape guide, 13 ... Erase head, 14 ... Pinch roller, 15 ... Pinch arm, 17 ... Stop lever, 18 ... Playback lever, 1
9... Recording lever, 20... Lock plate, 21... Lever, 25, 26... Intermediate gear, 27a... Intermediate small gear.

Claims (1)

[Claims] 1 In a cassette tape recorder that winds a magnetic tape that is fed at a constant speed using a capstan and a pinch roller, a capstan gear that rotates in synchronization with the capstan, a pinch roller gear that rotates in synchronization with the pinch roller, and a magnetic tape are A reel gear that drives the reel to be wound, a first intermediate gear that transmits the power of the capstan gear to the reel gear, and a first intermediate gear that transmits the rotational force of the reel gear to the pinch roller gear and that controls the circumferential speed of the capstan and the pinch during recording and playback. A second intermediate gear and a third intermediate gear are arranged so that the circumferential speeds of the rollers are the same, and the second intermediate gear is pivotally attached to one end and rotatably pivotally attached to the support shaft of the third intermediate gear. and a lever that is biased in the direction of gear meshing,
A cassette tape recorder characterized in that when the pinch roller stops due to the end of the tape, the aforementioned lever is rotated and the lock plate is moved by the lever to return the playback state to the stop state.