JPS6241425Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a magnetic tape cartridge featuring a reel brake means for preventing tape slack.

As a typical conventional reel brake means, the one shown in FIG. 6 is well known. In this method, rectangular engaging teeth 6 are continuously formed at regular intervals on the outer periphery of the lower flange 3b of the tape reel 3, and adjacent engaging teeth 6.
A locking pawl 8 is engaged between the reels 6 and 6 to prevent the reel from rotating when not in use. However, the purpose of this conventional structure is to lock the tape reel 3 from rotating in the tape payout rotation direction A when not in use, and to rotate the tape reel 3 in the tape winding rotation direction B to loosen the tape. It is not intended to be absorbed. Therefore, depending on the degree of contact between the locking pawl 8 and the engagement teeth 6, the rotation of the tape reel 3 may be locked while the tape reel 3 rotates freely in the tape payout rotational direction A by the amount indicated by P in the figure. When the amount of free rotation of the two reels 3 is added to the magnetic tape 2, the magnetic tape 2 is considerably loosened at the front of the main body case 1, causing misloading and damage to the tape.

In order to solve this problem, the system shown in FIG. 7 has been proposed. (Utility Model Publication No. 53-3014).
This has serrated engagement teeth 1 on the outer periphery of the lower flange 3b.
6 is continuously formed, and a locking pawl 8 is formed on this engaging tooth 16.
is engaged and biased to lock the tape reel 3 from rotating in the tape feeding rotational direction A, and
The tape winding device is designed to actively rotate in the tape winding rotation direction B to tighten the tape.

According to this, it is possible to reliably prevent tape slack from occurring when the tape is not in use. However, upon closer observation, the tip trajectory S of the locking pawl 8 crosses the plurality of engaging teeth 16, so the locking pawl 8
When the tape reel 3 is disengaged from one engagement tooth 16, a force acts that interferes with the adjacent engagement tooth 16 and pushes the tape reel 3 back in the tape feeding rotation direction A and rotates it. In addition, since the magnetic tape 2 tends to be tightly wound around the reel 3, the reel itself tends to return to the feeding rotation direction A due to the tape winding reaction force when the reel brake is released. Therefore,
These actions work together, and when the magnetic tape cartridge is pushed into the cassette deck and loaded and the reel brake is released, the tape reel 3 rotates significantly in the tape feeding rotation direction A, and the magnetic tape 2
It is considered that there is a possibility that the tape may become loose at the front of the main body case 1, which may interfere with the next tape loading operation.

This invention focuses on this fact, and when the magnetic tape cartridge is not in use, the tape reel is rotated to a necessary and sufficient extent in the tape winding direction using the locking claw to absorb tape slack as much as possible. The first purpose. A second purpose is to prevent the tape reel from returning to the tape feeding rotation direction and rotating when the reel brake is released.

Hereinafter, a specific example thereof will be explained based on the drawings.

FIG. 1 shows an example of a video magnetic tape cartridge. Inside a main body case 1 consisting of upper and lower divided cases 1a and 1b, there are a pair of left and right tape reels 3 and 3 on which magnetic tape 2 is wound. is rotatably mounted. The magnetic tape 2 is fed out from one reel 3 to the front of the main body case 1 and wound onto the other reel 3. A front cover 4 is attached to the main body case 1 so as to be openable and closable for covering the outer front surface of the main body case 1 and protecting the magnetic tape 2. This front lid 4
When a magnetic tape cartridge is loaded into the VCR, it automatically opens to allow tape loading, and when removed from the VCR, it automatically closes.

A set of reel brake means 5, 5 that act on the left and right tape reels 3, 3 is provided at the rear central portion of the main body case. The details are shown in FIGS. 2 to 4. First, each tape reel 3 has upper and lower flanges 3a and 3b, and rectangular engagement teeth 6 are continuously formed at regular intervals L on the outer periphery of the lower flange 3b. A locking pawl 8, which is urged to rotate toward the engagement tooth 6 by a helical spring 7, is pivotally supported by a post 9 that stands up from the inner bottom surface of the main case 1. The tip of the locking pawl 8 is located on the side of the tape payout rotation direction A of the reel 3 relative to the post 9, and is adapted to engage with a side wall 6a of the engagement tooth 6 facing in the tape payout rotation direction A. Further, the tip of the locking pawl 8 is set to abut against the uneven surface of the engagement tooth 6 at an intersecting angle of 10° or more, preferably 30° to 60°.

When the magnetic tape cartridge is pushed into the video deck and loaded, the pusher 11, which is pushed in through the through hole 10 provided in the lower case 1b, releases the operating tool 12.
is pushed up and swung, and the intermediate swinging member 13 is swung by this operating tool 12, whereby the arm 14 that is integrated with the locking claw 8 is pushed, and the tip of the locking claw 8 is brought into contact with the tape reel 3. The reel 3 is disengaged from the engaging teeth 6 and becomes free rotating.

When the magnetic tape cartridge is removed from the video deck, each reel brake means 5 operates to stop each tape reel 3 from freely rotating. In other words, the locking pawl 8 is pressed against the outer circumferential surface of the reel 3 by the biasing force of the spring 7 and engages between the adjacent engaging teeth 6, so that the tip of the locking pawl 8 feeds out the tape of the engaging tooth 6. The reel 3 is rotated in the tape winding rotation direction B by contacting the side edge 6a on the rotation direction A side. And reel 3
As the hook rotates, the point of contact between the tip of the locking pawl 8 and the side edge 6a moves toward the center of rotation of the reel, and reaches its limit at the base end of the side edge 6a, as shown by the imaginary line in FIG.

From the state shown by the imaginary line in FIG. 4, the locking claw 8
When retracting, the tip trajectory S of the locking pawl 8 is set so that the tip of the locking pawl 8 does not interfere with the adjacent engaging tooth 6 on the tape feeding rotation direction A side. That is, even if the locking pawl 8 is retracted from the state in which the reel 3 is rotated to the maximum extent in the tape winding rotation direction B by the locking pawl 8, the reel 3 is rotated in the tape winding rotation direction by the locking pawl 8. Return to A and set so that it will not rotate.
For this purpose, as shown in FIG. 5, the length l in the circumferential direction at which the distal end trajectory S of the locking pawl 8 intersects the moving area of the engaging tooth 6 having a height h, that is, the reel 3 is attached to the tape by the locking pawl. The maximum amount that can be rotated in the winding rotation direction B is
It is set to be less than the distance L between adjacent engaging teeth 6.

As explained above, according to this invention, when the locking pawl 8 comes into contact with the side edge 6a of the engaging tooth 6,
Since the engagement biasing force of the locking pawl 8 applies a rotational force to the tape reel 3 in the tape winding rotation direction B,
Tape slack can be absorbed as necessary and sufficiently. Also,
Even when the reel brake is released from a state in which tape slack has been absorbed by the reel rotation by the locking pawl 8, the retracting locking pawl 8 interferes with the engagement teeth 6, causing a phenomenon in which the reel 3 is returned to the tape payout rotation direction A. First, it has been possible to prevent tape slack as much as possible when loading a magnetic tape cartridge into a cassette deck.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view of a magnetic tape cartridge according to the present invention, and FIG.
3 is a sectional view taken along the Y--Y line in FIG. 1. Fig. 4 is a plan view showing the engagement state between the engagement teeth and the locking pawl of the tape reel, which is a component of the present invention, and Fig. 5 also illustrates the engagement relationship between the engagement teeth and the locking pawl. FIG. FIGS. 6 and 7 are plan views of main parts of different conventional examples. 1...Body case, 2...Magnetic tape, 3...
Tape reel, 3b...lower flange, 4...front cover, 5...reel brake means, 6...engaging teeth,
6a...Side edge of engaging tooth, 7...Spring, 8...Latching claw, 9...Pivot point (post) of locking claw, A...Tape feeding rotation direction, B...Tape winding rotation direction.

Claims (1)

[Claim for Utility Model Registration] Square engaging teeth 6 are continuously formed at regular intervals L on the outer periphery of the lower flange 3b of the tape reel 3 installed inside the main body case. In a magnetic tape cartridge in which a locking pawl 8, which is engaged and biased by a spring 7, is rotatably supported between the teeth 6 and 6, and the tape reel 3 is prevented from rotating when not in use, The tip of the locking pawl 8 is located on the side of the tape reel 3 in the tape payout rotational direction A from its pivot point, and is urged into contact with the side edge 6a of the engagement tooth 6 facing in the tape payout rotational direction A. The reel 3 is urged to rotate in the tape winding rotation direction B, and the maximum pressing rotation amount l of the reel 3 by the locking pawl 8 is set to be less than the distance L between the adjacent engaging teeth 6. A magnetic tape cartridge characterized in that the locking pawl 8 is separated from the engagement tooth 6 during use.