JPS6331255Y2 - - Google Patents

Description

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

Generally, a video magnetic tape cartridge has a reel brake means that directly engages the tape reel to prevent the tape reel from rotating in the tape slack direction when not in use.

However, in reality, even when the reel brake is applied, there is room for the tape reel to wobble or for tape slack to occur in the tape running system due to play in the brake itself. It only applies a rotational brake, but does not have a function to actively rotate the tape reel in the direction of tape tension when the tape is slack. Therefore, if the tape slack remains and the magnetic tape is loaded into the video deck with the tape loosened at the front of the case, it often occurs that the tape pulling out operation by the tape pulling pin on the video deck side is hindered.

In addition, when the tape reel is locked in rotation with the magnetic tape in a tensioned state by the reel brake means, if the tape reel shakes due to a strong impact, the magnetic tape will stretch due to the instantaneous tensile load applied to the magnetic tape. There was a risk of deformation or, in the worst case, the tape breaking.

This invention focuses on this fact, and even if the magnetic tape becomes slack due to the rattling of the tape reel when not in use, the tape can be loosened and returned to a taut state. The purpose is to prevent deformation and damage to the product. The principle is that the tape reel is allowed to rotate in the tape loosening direction by applying rotational resistance, and the tape reel is rotated back in the tape tensioning direction by the amount of rotation in the tape loosening direction.

The details will be explained below based on the video magnetic tape cartridge shown in the drawings.

In FIG. 1, 1 is a main body case. This is made up of upper and lower plastic cases 1a and 1b screwed together with their lids mating, and has drive shaft insertion holes 3, 3 on the left and right sides of the center of the bottom wall 2 of the case.

Inside the main body case 1, on the left and right sides, tape reels 5, 5, on which the magnetic tape 4 is wound, are rotatably positioned over the respective drive shaft insertion holes 3, 3.

As shown in FIG. 2, each tape reel 5 is a plastic molded product having flanges 8 and 9 on the upper and lower sides of a hub 7 having a top plate 6, and an annular rib 10 at the lower end of the hub 7 is inserted into each drive shaft. It is loosely fitted into the hole 3 and is freely movable within a certain range in the radial direction, as well as vertically movable.

Various guide members 11, 11 are arranged at the front left and right end portions of the main body case 1, and the magnetic tape 4 is guided by these guide members 11 and unwound from the supply side tape reel 5 on the right side in the figure, and then the magnetic tape 4 is fed out from the supply side tape reel 5 on the right side of the figure. The tape passes through the front and is wound onto the winding side tape reel 5 on the left side.

12 is a front cover for protecting the tape. This is rotatably supported in front of the main body case 1 so as to be openable and closable, and when the magnetic tape cartridge is not in use, it covers and protects the outside of the front surface of the magnetic tape led out to the front of the case. When the magnetic tape cartridge is loaded into the video deck, the front cover 12 opens upward and the magnetic tape 4 is placed in a standby state in which it can be pulled out to the front of the case.

A tape drawer pocket 13 with an open bottom and front side is recessed in the front of the main body case 1, and a tape drawer pin on the video deck side can be inserted into the pocket 13 when the front lid 12 is open. The magnetic tape 4 is inserted into the inside of the magnetic tape 4, and by movement of the tape pull-out pin, the magnetic tape 4 is pulled out to the front of the case and wound around the rotating head on the video deck side.

In this basic structure, the present invention is characterized by a reel brake means.

2 and 3 show a first embodiment of the reel brake means 15. First, each tape reel 5 has a protrusion at the end of the drive shaft 16 on the video deck side at the center of the top plate 6 of the hub 7. A through hole 17 into which the portion 16a fits is provided. And the top plate 6 of the hub 7
An engagement plate 18 that removably engages with the upper surface of the top plate 6 is placed on top so as to be movable up and down, and a compression coil spring 20 is installed between the case upper wall 19 and the engagement plate 18. The compression coil spring 20 has one end 20a inserted and fixed into the case upper wall 19, and the other end 20a.
0b is inserted and fixed into the engagement plate 18, and the engagement plate 18 is urged to engage with the upper surface of the hub top plate 6. In the illustrated example, a large number of engagement holes 21 having a vertical engagement surface 21a and an inclined surface 21b following the vertical engagement surface 21a are recessed at regular intervals on an imaginary circle concentric with the through hole 17 on the upper surface of the hub top plate 6, By protruding on the lower surface of the engaging plate 18 a protrusion 22 that corresponds to and engages with the engaging hole 21, the engaging plate 18 engages with the upper surface of the top plate 6 in a concave-convex fit. did.

In this case, when the magnetic tape cartridge is not in use, the engagement plate 18 is always fitted and engaged with the upper surface of the hub top plate 6 under the spring pressure of the compression coil spring 20, and rotational resistance is imparted to each tape reel 5. has been done. Therefore, each tape reel 5 rotates freely in response to a slight external impact, and the running system of the magnetic tape 4 does not become slack. However, since the rotation of each tape reel 5 is not completely locked, the tape reel 5 may wobble due to a large external shock, and if abnormal tension is momentarily applied to the magnetic tape 4, compression may occur. The coil spring 20 is twisted and the tape reel 5 rotates in the tape loosening direction (in the direction of arrow B in FIG. 3), thereby buffering the tension applied to the magnetic tape 4. Next, under the dynamic restoring force of the twisted compression coil spring 20, the tape reel 5 rotates back in the opposite tape tensioning direction (in the direction of arrow A in FIG. 3) by the amount of rotation in the tape loosening direction B.
The magnetic tape 4 wound between both tape reels is always maintained in a tensioned state.

When a magnetic tape cartridge is loaded into a video deck, the drive shaft 16 on the video deck side engages with the hub hole 7a of each tape reel 5 through the drive shaft insertion hole 3, and the tip stepped surface 16b of the drive shaft 16 engages with the hub hole 7a of each tape reel 5.
comes into contact with the lower surface of the hub top plate 6, and the tip protrusion 16a fits into the through hole 17 to push up the engagement plate 18 against the compression coil spring 20.
is removed from the hub top plate 6, and each tape reel 5 becomes freely rotating.

In addition, in the present invention, the reel brake means 1
5 may be provided only on one of the left and right tape reels 5, 5.

FIG. 4 shows another embodiment of the present invention, in which the tape reel 5 has a lower flange 9 integrally connected to the outer periphery of the lower end of the hub 7, and a separate upper flange at the upper end of the hub 7. 8 are fixed by ultrasonic welding, the through hole 17 is transparently provided in the center of the top plate 6 of the hub 7 and the upper flange 8, and an engagement plate 18 is provided on the upper surface of the center part of the upper flange 8 as in the above embodiment. They are designed to engage in a similar configuration.

Further, FIG. 5 shows yet another embodiment of the present invention, in which a recessed hole 24 into which the engagement plate 18 is fitted is formed on the upper surface of the central part of the upper flange 8 which is ultrasonically welded to the hub 7. The outer peripheral side of the engagement plate 18 has a recessed hole 24
Engagement teeth 2 provided on both 18 and 24 on the inner circumferential side of the
5 and 26 so as to be removably engaged.

Furthermore, the engagement plate 18 is connected to the hub top plate 6 or the upper flange 8.
It may be in a form that simply frictionally engages with the upper surface of the holder.

As explained above, since the reel brake means 15 according to this invention is arranged between the hub top plate 6 of the tape reel 5 and the case upper wall 19, it does not require a large space in terms of plane, and is particularly This is advantageous when trying to downsize the magnetic tape cartridge. In addition, since the tape reel 5 is allowed to rotate in the tape loosening direction B, and then returns to rotate in the opposite tape tensioning direction A, the magnetic tape 4 can be kept in a constant state by responding well to momentary external shocks. In addition to maintaining the magnetic tape 4 in a tensioned state, deformation and damage to the magnetic tape 4 can be effectively prevented.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view showing a specific example of a magnetic tape cartridge to which the present invention is applied, Fig. 2 is a vertical cross-sectional view of its main parts, and Fig. 3 is a tape that is a component of the present invention. FIG. 6 is a developed view illustrating the state of engagement between the upper surface of the top plate of the hub of the reel and the engagement plate. FIGS. 4 and 5 are longitudinal cross-sectional views of essential parts showing different embodiments of the present invention. 1... Main body case, 2... Case bottom wall, 4...
Magnetic tape, 5... Tape reel, 7... Tape reel hub, 6... Hub top plate, 16... Drive shaft, 17... Through hole, 18... Engagement plate, 19...
Case upper wall, 20... Compression coil spring, 20a...
...one end of the compression coil spring, 20b...the other end of the compression coil spring.

Claims (1)

[Scope of utility model registration request] A tape reel 5 on which magnetic tape 4 is wound around the main body case 1 is inserted into a transparent drive shaft insertion hole 3 in the bottom wall 2 of the case.
In a magnetic tape cartridge rotatably located above and built in, a protrusion 16 at the tip of a drive shaft 16 on the deck side is attached to the top plate 6 of the hub 7 of the tape reel 5.
A through-hole 17 into which a is inserted is provided, and an engagement plate 18 is arranged on the top plate 6 of the hub 7 so as to be movable up and down. A compression coil spring 20 whose other end 20b is fixed to the engagement plate 18 is attached to 19, and when not in use, the compression coil spring 20 elastically biases the engagement plate 18 into a position in which it engages with the tape reel 5 side. . A magnetic tape car characterized in that, when loading onto a deck, the engagement plate 18 is pushed up to a position where it floats away from the tape reel 5 by the tip protrusion 16a of the drive shaft 16 on the deck side that fits into the through hole 17. Tritsuji.