JPH0626034B2 - Tape end detection mechanism - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape end detection mechanism for detecting in a tape player that a tape that has run has reached its end and the reel base has stopped. Is.

(Technical background of the invention) One of the tape end detection mechanisms used in a tape player uses a check plate frictionally fitted to a rotating reel base. This is because when the reel base is rotating, its frictional force urges the check plate in the rotation direction, and while the check plate is urged at a certain angle, it detects that the tape is running. .. On the other hand, when the rotation of the reel base is stopped, the frictional force from the reel base is lost and the check plate is biased to a certain rotation angle, so that the tape end is determined.

In order to detect the angle of the check plate, the check gear is moved by the driving force of the motor using a cam gear that constantly rotates, and the change in the angle of the check plate is extracted as the change in the swing amount of the check link.

An example of this type of tape end detection mechanism is shown in FIGS. 2 and 3.

That is, the check plate 2 rotatably provided on the support shaft 1 is frictionally interlocked with a reel base (not shown). The check plate 2 is provided with a Y-shaped groove 3 and a protrusion 4 is formed at a branch portion thereof.

The cam gear 5 for detecting the tape end rotates about its supporting shaft 6. On the surface of the cam gear 5, an inner cam 7 centered on the shaft 6 and a minimum diameter portion 7a of the inner cam 7 are formed.
An island-shaped cam 8 is formed which has a starting point nearby and is separated from the inner cam 7.

On the other hand, the check link 1 that rotates about the support shaft 10
A guide pin 12 that moves on the surface of the cam gear 5 is provided at the tip of the first arm 11a. Here, P1 to P5 shown on the surface of the cam gear 5 in the drawing are the guide pins 12
Indicates a moving position, and P1 to P4 are located closer to the support shaft 6 side than the maximum diameter portion of the inner cam 7. P2 is located farther from the spindle 6 than the tip portion 8a of the island cam 8 is. P5 is located at a position corresponding to the maximum diameter portion 8b of the island cam 8.

A pin 13 to be inserted into the Y-shaped groove 3 of the check plate 2 is provided at the tip of the second arm 11b of the check link 11. Further, the spring 1 that biases the guide pin 12 toward the support shaft 6 side of the cam gear 5 is provided on the third arm 11c.
The fourth arm 11d has a pressing portion 15 for operating a channel change mechanism (not shown).

A drive gear (not shown) interlocking with the motor is provided in the cam gear 5, and the cam gear 5 meshes with the drive gear so that the cam gear 5 is constantly rotating.

The operation of the tape end detection mechanism having such a configuration is as follows.

First, in the play state, the cam gear 5 for detecting the tape end constantly rotates counterclockwise in the figure by the action of the drive gear that is interlocked with the motor. On the other hand, if the tape player is running in the forward direction and the reel base (not shown) is rotated clockwise by the driving force of the motor, the check plate 2 frictionally linked to the reel base. Is kept rotated in the clockwise direction in the figure about the spindle 1.

In this state, the check link 11 is biased counterclockwise in the figure by the spring 14 about the support shaft 10 and the tip of the check plate 2 is held in the clockwise direction. The pin 13 of the second arm 11b of the Y-shaped groove 3 is the tip P of the Y-shaped groove 3 on the right side in the drawing.
It can be moved up to 1. Therefore, the guide pin 12 at the tip of the first arm 11a of the link 11 is always biased in the clockwise direction, and the guide pin 12 is rotated as the cam gear 5 rotates.
Moves along the surface of the inner cam 7 of the cam gear 5.

By the way, when the guide pin 12 moves between the minimum diameter P1 and the maximum diameter P4 of the inner cam 7, the pin 13 of the second arm 11b causes the tip P1 of the branch portion of the branch portion on the Y-shaped groove 3.
And between the straight line intermediate position P4. That is,
The movement range of the check link 11 in the play state is
Since each of the pins 12 and 13 is limited to the range of movement within P1 to P4, the check link 11 does not rotate to the maximum clockwise direction in the drawing. Therefore, the fourth arm 1
The channel change mechanism is not operated via the pressing portion 15 provided in 1d.

On the other hand, when the guide pin 12 is pressed from the minimum diameter portion 7a of the inner cam 7 toward the maximum diameter portion in the state where the reel base is stopped rotating at the tape end, the pin 13 of the check link 11 becomes Y. The check plate 2 moves from the branch portion of the character groove 3 toward the straight portion P4 and is pushed by the pin 13 to rotate the check plate 2 to the neutral position (position in FIG. 3). In this state, when the pin 13 tries to return to the branch portion side of the Y-shaped groove again, while the reel base is rotating, the friction force causes the check plate 2 to rotate clockwise.
Since the rotational force is lost, the angle of the check plate 2 remains the same as when the pin 13 was at P4. As a result, since the protrusion 4 comes on the movement path of the pin 13, it becomes impossible for the pin 13 to enter the branch portion side from the branch point P3.

That is, when the reel base is rotating, the guide pin 12 can hang along the surface of the inner cam 7 at its minimum diameter portion by inserting the pin 13 into the branch portion. Since the check link 11 cannot be further rotated in the counterclockwise direction because it hits the protrusion 4 at the position, the guide pin 12 stops at the position P2. When the cam gear 5 further rotates in this state, the guide pin 12 separates from the surface of the inner cam 7 as it approaches the smallest diameter portion 7a of the inner cam 7, and the tip end portion of the island cam 8 closer to the support shaft 6 than P2. 8a enters the inside of the guide pin 12 and rides on the island-shaped cam 8.

The guide pin 12 is pushed by the island-shaped cam 8, and accordingly the check link 11 is pushed clockwise in the drawing, and the pin 13 in the Y-shaped groove 3 also leaves the projection 4 and moves to the tip P5 side of the Y-shaped groove. To do. Then, as shown in FIG. 3, when the guide pin 12 comes to the maximum diameter 8b of the island-shaped cam 8, that is, when the guide pin 12 falls to P5, the pin 13 of the second arm 11b of the check link. Moves to the end P5 of the straight portion on the Y-shaped groove 3. When the pin 13 is at P5 of the Y-shaped groove, the check link 11 rotates more clockwise than when the pin 13 is at P4. Therefore, the pressing portion 15 provided on the fourth arm 11d is rotated. The channel change mechanism (not shown) can be operated by.

In the above description, the reel base is rotated in the forward direction, and the check plate 2 is rotated clockwise in the drawing in accordance with the rotation. However, when the reel base is rotated in the reverse direction. Since the check plate 2 rotates counterclockwise in the figure, the pin 13 of the check link 11 moves from the straight portion of the Y-shaped groove 3 in the left branch portion.

(Problems of Background Art) In the conventional tape end detection mechanism as described above, the angle of the check plate 2 may be displaced due to uneven rotation of the reel base caused by the looseness of the tape, or the tape player may experience external vibration. If added, the check link 11 may swing away from the inner cam 7, and the guide pin 12 may not draw the original trajectory. In this case, since the tip 8a of the island-shaped cam 8 is formed in an acute angle shape, even if such an inconvenience occurs, it is normally guided by the tip of the island-shaped cam 8 and the original locus (the inner cam or the island-shaped cam). There is no problem because it returns to the surface of the cam), but depending on the timing at that time, the guide pin 12 hits the tip of the island-shaped cam 8 and both lock, and the force of the drive gear is forcibly applied to the check link 11. The drive system and the tape end detection mechanism may be damaged.

Particularly, in the conventional detection mechanism, the check link 11
Since both the cam gear and the cam gear are made of a rigid body, it is inevitable that a serious damage accident will occur once the lock occurs.

An object of the present invention is to prevent the guide pin from being elastically deformed even if an unreasonable force is applied between the island-shaped cam and the guide pin of the check link even if they are locked. An object of the present invention is to provide a tape end detection mechanism that prevents damage to the drive system and the detection mechanism by letting the tip end of the island-shaped cam escape from the front.

(Summary of the Invention) In the tape end detection mechanism of the present invention, the check link is made of an elastic member such as synthetic resin, and a deformable spring portion is formed in a part of the check link, thereby forming an island cam. When the guide pin meshes with and an unreasonable force is applied, the check link is elastically deformed to allow the guide pin to escape from the front surface of the tip end portion of the island-shaped cam.

(Embodiment of the Invention) One embodiment of the present invention will be specifically described below with reference to FIG. The same members as those in the conventional tape end detection mechanism shown in FIGS. 2 and 3 are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the check link 11 is made of an elastic member such as synthetic resin. A spring portion 50 curved in a U shape is formed in the middle of the first arm 11 a of the check link 11. Therefore, the first arm 11
The guide pin 12 provided at the tip of a is the spring portion 5
The first arm 11a can be moved from the 0 portion as the first arm 11a is deformed.

In the mechanism of the present embodiment having such a configuration, even if the front surface of the tip end portion of the island cam 8 and the guide pin 12 are meshed with each other for some reason, if a certain force or more is applied, the first
Since the arm 11a of the is deformed from the portion of the spring portion 50, the guide pin 12 can escape from the front surface of the island-shaped cam 8.

It should be noted that the present invention is not limited to the above-described embodiment, and the arm itself of the check link may not be deformed, but only the mounting portion of the guide pin 12 may be deformed. Further, as the Y-shaped groove, a hole-shaped groove penetrating the check plate 2 or a groove in which the surface of the check plate 2 is recessed in a Y-shape can be used.

(Effects of the Invention) As described above, according to the present invention, it is possible to prevent the island-shaped cam and the guide pin from being locked by forming the check link from the elastic member and providing the check link with the spring portion. There is an effect that it is possible to provide a tape end detection mechanism in which there is no fear of damage to the drive system or the detection mechanism.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a tape end detecting mechanism of the present invention, FIGS. 2 and 3 are plan views showing an example of a conventional mechanism, and FIG. FIG. 3 shows the reel base in a stopped state. 2 ... Check plate, 3 ... Y-shaped groove, 5 ... Cam gear, 7 ... Inner cam, 8 ... Island type cam, 11 ... Check link, 11a ... Check link first arm, 50
...... U-shaped spring part provided on the check link, 12 ...
… Guide pin, 13 …… pin, 20 …… drive gear.

Claims (2)

[Claims] 1. A check plate which is frictionally interlocked with a reel base to be urged in the rotation direction thereof, a Y-shaped groove provided in the check plate, an inner cam on the surface, and a part separated from the inner cam. The cam gear is provided with an island-shaped cam and is constantly driven, and the first and second arms are rotatably supported by a support shaft and extend in two directions from the support shaft portion. The first arm has a cam gear. A guide pin that follows the cam on the surface is provided, and a check link having a pin that is inserted into the Y-shaped groove is provided on the second arm, and the check link is made of an elastic member such as synthetic resin. The tape end detection mechanism is characterized in that the first arm of the check link is formed with a spring portion that is deformable in a direction that allows the guide pin to escape from the front of the tip of the island-shaped cam. 2. The tape end detection mechanism according to claim 1, wherein the spring portion is formed by bending an intermediate portion of the first arm into a U shape.