JPS61240464A - Tape end detecting mechanism - Google Patents

Abstract

PURPOSE:To avoid the locking between an island-shaped cam and a guide pin as well as the breakdown of a drive system or a detection mechanism, by using an elastic member for a check link and adding a spring part. CONSTITUTION:A check link 11 is made of an elastic member like synthetic resin, etc. and a U-shaped spring part 50 is formed at the middle part of an arm 11a of the link 11. The arm 11a is deformed at the part of the spring part 50 and a guide pin 12 can get out of the front of an island-shaped cam 8 with application of a force larger than a fixed level even in case the pin 12 provided at the tip of the arm 11a engages the front of the tip part of the cam 8.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a tape end detection mechanism in a tape player that detects that a running tape has reached its end and the reel base has stopped. be.

[Technical Background of the Invention] One tape end detection mechanism used in tape players utilizes a check plate that is frictionally fitted to a rotating reel base. This means that while the reel base is rotating, the check plate is biased in the rotating direction by its frictional force, and while this check plate is biased at a certain angle, it detects that the tape is running. When the rotation of the reel base stops, the frictional force from the reel base is lost, and when the check plate is no longer biased to a certain rotation angle, the end of the tape is determined. In addition, in order to detect the angle of the check plate, the check link is moved using a cam gear that constantly rotates using the driving force of the motor, and the change in the angle of the check plate is detected as a change in the amount of swing of the check link. There is.

An example of this type of tape end detection mechanism is shown in FIG.

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

On the other hand, the cam gear 5 for tape end detection has its spindle 6
The surface has an inner cam 7 centered on the shaft 6 and a starting point near the small diameter part 7a of the inner cam 7,
An island-shaped cam 8 separate from the inner cam 7 is formed. The first check link 11 rotates around 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 arm 11a. Also check link 1
A pin 13 that is inserted into the Y-shaped groove 3 of the check plate 2 is provided at the tip of the second arm 11b. Furthermore, the guide pin 12 is connected to the cam gear 5 on the third arm 11C.
A spring 14 biasing the fourth arm 11 toward the support shaft 6 side
d is formed with a pressing portion 15 that operates a channel change mechanism (not shown).

On the other hand, a drive gear 20 interlocked with a motor is provided adjacent to the cam gear 5, and the cam gear 5 meshes with the drive gear 20, so that the cam gear 5 constantly rotates.

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

First, in the play state, the tape end detection cam gear 5 rotates counterclockwise in the figure in conjunction with the motor. On the other hand, if the reel base (not shown) is rotating counterclockwise in the figure due to the driving force of the motor, then the check plate 2 frictionally interlocked with the reel base
is kept rotated in the right direction in the figure about the support shaft 1.

In this state, the check link 11 is urged counterclockwise in the figure by the spring 14 around the support shaft 10, and since the check plate 2 is held rightward, the check link 11 2 arm 11t)
Since the pin 13 is movable to the tip P1 of the branch part of the Y-shaped groove 3, the first arm 11a of the link 11 is always biased to the left, and as the cam gear 5 rotates, the guide pin 12 Move the inner cam 7. By the way, when the guide pin 12 is at the minimum diameter P1 and the maximum diameter P4 of the inner cam 7, the pin 13 of the second arm 11b is at the tip P1 of the branch part on the Y-shaped groove 3 and the intermediate position of the straight part. It's on P4.

That is, since the movement range of the check link 11 in the play state is limited to the range in which each pin 12° 13 moves within P1 to P4, the check link 11 cannot rotate clockwise at the maximum in the figure. Therefore, the fourth arm 1
The channel change mechanism is not operated via the pressing portion 15 provided at 1d.

On the other hand, when the reel base stops rotating at the tape end, the check plate 2 rotates to the neutral position. In this state, since the protrusion 4 is on the movement path of the pin 13 of the second arm 11b of the check link 11, the pin 13 is controlled to move only in a straight line from the branch point P3, and therefore the guide pin 12 is also controlled to be closer to the outer diameter than P3. In this state, when the cam gear 5 further rotates, the guide pin 12 separates from the inner cam 7 at the small diameter portion of the inner cam 7 and rides on the island-shaped cam 8 . Then, when the guide pin 12 reaches the maximum diameter P5 of the island-shaped cam 8,
The pin 13 of the second arm 11b moves to the end P5 of the straight part on the Y-shaped groove 3, and therefore the check link 11 rotates in the maximum clockwise direction in the figure. The channel change mechanism operates via the pressed pressing portion 15.

[Problems with the Background Art] However, in the conventional tape end detection mechanism as described above, the angle of the check plate 2 may shift due to uneven rotation of the reel base caused by slack in the tape, or external vibrations may occur in the tape player. If this happens, the check link 11 may swing away from the inner cam 7, and the guide pin 12 may no longer follow its original trajectory. In this case, since the tip of the island-shaped cam 8 is formed into an acute angle,
Even if such an inconvenience occurs, there is usually no problem because the tip of the island-shaped cam 8 will guide you back to the original trajectory (inner cam or surface of the island-shaped cam), but depending on the timing, the guide pin 12 hits the tip of the island-shaped cam 8 and locks the two, and the force of the drive gear is forcibly applied to the check link 11, potentially causing damage to the drive system and tape end detection mechanism. In particular, in the conventional detection mechanism, since both the check link 11 and the cam gear are constructed of rigid bodies, once locking occurs, it is inevitable that serious damage will occur.

[Object of the Invention] The object of the present invention is to prevent the check link from elastically deforming even if the island-shaped cam and the guide pin of the check link become locked and an unreasonable force is applied between them. Another object of the present invention is to provide a tape end detection mechanism that prevents damage to the drive system and detection mechanism by letting the guide pin escape from the front of the tip of the island-shaped cam.

[Summary of the Invention] The tape end detection mechanism of the present invention has a check link made of an elastic member such as a synthetic resin, and a deformable spring portion is formed in a part of the check link, so that the tape end detection mechanism can be used as an island-shaped cam. When the check link engages with the guide pin and an unreasonable force is applied, the check link is elastically deformed and the guide pin is released from the entire surface of the tip of the island-shaped cam.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. Note that the same members as those in the conventional tape end detection mechanism shown in FIG. 2 are designated by the same reference numerals, and a description thereof will be omitted.

In this embodiment, the check link 11 is made of an elastic member such as synthetic resin. A U-shaped spring portion 50 is formed in the middle of the first arm 11a of the check link 11.

Therefore, the guide pin 12 provided at the tip of the first arm 11a can move as the first arm 11a deforms from the spring portion 50.

In the mechanism of this embodiment having such a configuration, for some reason, the front end of the island-shaped cam 8 and the guide pin 1
2 are engaged with each other, if a force equal to or greater than the negative chamber is applied, the first arm 11a deforms from the spring portion 50, allowing the guide pin 12 to escape from the front of the island-shaped cam 8.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and instead of deforming the arm of the check link itself, only the mounting portion of the guide pin 12 may be deformed.

[Effects of the Invention] As described above, according to the present invention, locking between the island-shaped cam and the guide pin can be prevented by a simple structure in which the check link is made of an elastic member and a spring portion is provided in the check link. , it is possible to provide a tape end detection mechanism without fear of damage to the drive system or detection mechanism.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the tape end detection mechanism of the present invention, and FIG. 2 is a plan view showing an example of a conventional mechanism. 2... Check plate, 3... Y-shaped groove, 5...
Cam gear, 7...Inner cam, 8...Island cam, 11
... Check link, 11a... First arm of check link, 50... U-shaped spring portion provided on check link, 12... Guide pin, 13... Pin, 2
0... Drive gear. 111Figure 11c14 Figure 2

Claims (2)

[Claims] (1) a. A check plate that is frictionally interlocked with the reel base and biased in its rotational direction. b, Y-shaped groove provided in the check plate. c. A cam gear that has an inner cam on its surface and an island-shaped cam separated from the inner cam and is constantly driven to rotate. d. A check link rotatably supported by a support shaft and comprising a pin inserted into the Y-shaped hole and a guide pin that follows the cam on the surface of the cam gear. A tape end detection mechanism, characterized in that 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. (2) A claim in which the check link has an arm extending from its support shaft, a guide pin is provided at the tip of the arm, and a U-shaped curved spring portion is formed in the middle of the arm. The tape end detection mechanism according to item 1.