JP2000243055A - Magnetic tape cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deflection of a brake member and to assure the smooth operation of the brake member by providing the flank erected with a brake arm of a thin part with a recessed part extending in a longitudinal direction near the boundary between the thick part and thin part in the horizontal plate part of the brake member. SOLUTION: The surface on the side erected with the brake arm 23 of the thin part is provided with a slit (recessed part) 22g in the longitudinal direction near the boundary part of the thick part and thin part of the horizontal plate part 22c to allow the stress at the time of resin solidification to escape. The rate of the solidification varies in the thick part 22d and the thin part 22e when the resin solidifies at the time of molding and, therefore, the thick part 22d shrinks and generates the stress to pull the thin part 22e to an inner side when the thin part 22e solidifies first, then the thick part 22d solidifies. The inner side of the horizontal plate part 22c of the brake member 22 is provided with the slit 22f or the slit 22g, by which the force to pull the thin part 22e is shut off and the inclination of the brake arm 23 may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape cassette, and more particularly to a magnetic tape cassette having an improved brake member for restricting the rotation of a take-up hub to prevent the magnetic tape housed in the magnetic tape cassette from becoming loose. About.

[0002]

2. Description of the Related Art As is well known, a magnetic tape cassette comprises a pair of take-up hubs or take-up reels around which a magnetic tape is wound after fixing the respective ends of a long magnetic tape. It is housed in a case (half) that exposes only the portion of the magnetic tape stretched between the hubs, and further covers the portion of the magnetic tape that is exposed from the half to protect the magnetic layer surface of the magnetic tape. And a front lid (lid) which is rotatably supported between a closed position where the magnetic tape is exposed and a spring biased to the closed position. The magnetic tape cassette rotates the front cover to the open position in conjunction with the loading of the recording / reproducing apparatus, and the rotation of one of the take-up hubs causes the magnetic tape from the other take-up hub to rotate. Information is recorded on or reproduced from the magnetic tape by an operation such as bringing the magnetic head of a recording / reproducing apparatus into contact with the magnetic tape that has been sent and exposed.

[0003] The magnetic tape wound around the take-up hub may be loosened due to vibration, impact or the like during conveyance, and may protrude little by little from the cassette and loosen between the two take-up hubs. When the loosened magnetic tape is loaded into a recording / reproducing apparatus as it is, the loosened magnetic tape may cause a failure of the recording / reproducing apparatus or expansion of the magnetic tape.

Therefore, a magnetic tape cassette provided with a brake device (brake member) for surely stopping the rotation of the winding hub when the magnetic tape is not used has been developed. For example, D
A brake device used in a DS cassette, a DAT cassette, or the like includes a gear integrally formed on the upper end surface of each winding hub coaxially with each winding hub of the magnetic tape, and a winding gear engaged with each gear. The take-up hub is movable between a braking position where the rotation of the take-up hub is prohibited in the winding loosening direction and a release position where the take-up hub is separated from the gear and allows the rotation of the take-up hub. A front cover is rotated to an open position in conjunction with loading into the recording / reproducing apparatus, and a brake member is moved to a release position by a protrusion provided on a part of the inside of the front cover. Has adopted.

FIG. 6 shows a perspective view of a conventional brake member 90, and FIG. 7 shows the brake member 90 and one of the winding hubs 9.
2 shows a plan view. The brake member 90 is composed of a long band-shaped horizontal plate portion 91 and brake arms 93 erected vertically at both ends in the longitudinal direction. The brake arm 93 is provided with legs 93 a provided vertically to the horizontal plate 91.
And an arm 93b extending from the leg 93a vertically and horizontally with respect to the longitudinal direction. The horizontal plate portion 91 has a gear 92 a provided on a winding hub 92.
A braking piece 91a is provided for inhibiting rotation of the winding hub 92 by engaging with the engaging piece. The center of the horizontal plate portion 91 is a thick portion 91b for receiving a brake spring (not shown) that urges the brake member 90 toward the take-up hub 92, and a brake arm 93 is provided upright outside the center. The portion 91c is a thin portion 91c.

[0006] The brake arm 93 is provided with a hook 93c at the tip of the arm 93b which engages with the projection of the front cover as the front cover rotates. The ends of the ribs that form the upright vertical portions are bent vertically to form horizontal portions, and an L-shaped contact portion 93d is provided between the vertical portions and the horizontal portions. This contact portion 93d
When the front cover is in the closed position for covering the magnetic tape, the front cover comes into contact with the projection of the front cover, and inhibits the brake member 90 from moving forward. Thus, even if a slight impact is applied to the cassette case, the brake member 90 moves forward to release the locking of the winding hub 92, and the winding hub 92 rotates, so that the magnetic tape does not loosen.

FIG. 8 is a transparent side view of the cassette case for explaining the operation of the front lid 94 and the brake member 90. In FIG. 8, reference numeral 96 denotes an upper half, and 98 denotes a lower half. When the magnetic tape cassette is not loaded in the recording / reproducing device (not shown), the brake member 90 is urged in the direction of arrow L 'by a brake spring (not shown),
The leading end of the brake piece 91a of the brake member 90 is
The second gear 92a engages with the second gear 92a to prohibit the rotation of the winding hub 92 (see FIG. 8A), and the end face of a projection 94b provided on the side plate 94a of the front cover 94 when the front cover 94 is in the closed position. Abuts against a contact portion 93d provided on a brake arm 93 of the brake member 90, and prevents the brake member 90 from moving to a release position allowing rotation of the winding hub 92 due to an impact or the like. I do.

On the other hand, when the magnetic tape cassette is loaded in the recording / reproducing apparatus, the front cover 94 is rotated around the support shaft 95 in the direction of arrow K as shown in FIG.
Moves to a position different from the closed position, the protrusion 94b provided on the side plate 94a of the front lid 94 moves away from the contact portion 93d of the brake member 90, and the brake member 9
0 is engaged with the gear 92a of the winding hub 92 only by the spring force of the brake spring. The rotation of the front cover 94 further proceeds, and when the rotation angle reaches a predetermined angle, the front cover 9 is rotated.
The fourth protrusion 94b abuts on the hook 93c at the tip of the leg 93b of the brake arm 93. As the front lid 94 further rotates, the projection 94b pulls out the hook portion 93c in the direction of the arrow L while hooking the hook portion 93c, and moves the brake member 90 to the release position (see FIG. 8C). As a result, the braking piece 91 is separated from the gear 92a, and the braking of the winding hub 92 is released. When the magnetic tape cassette is removed from the recording / reproducing apparatus, the above operation returns to the non-loaded state, that is, the front cover 94 is closed, the brake member 90 returns to the braking state, and the rotation of the winding hub 92 is prevented.

[0009]

As described above, the brake member 90 engages the projection 94b of the front cover 94 with the hook 93c of the brake arm 93, and moves along the upper half in accordance with the rotation of the front cover 94. Slide. However, when the brake member is formed by injection molding, the member may be deformed due to stress when the resin solidifies. As shown in FIG. 9A, a front view of the brake member 90 as viewed in the direction of arrow X in FIG. 6 has a thick portion 91b at the center and a thin portion 91c at the outside. Therefore, as shown by reference numerals A and B in FIG.
At the boundary of c or at the base of the brake arm 93, it may be bent inward (tilted).

When the brake arm 93 is tilted as shown in FIG. 9 (b), the projection 94b of the front lid 94 is hooked on the hook 93c at the tip of the brake arm 93 and pivots to move the brake member 90 to the release position. At this time, the projection 94b cannot hook the hook 93c and swings. Brake member 90 when missed
Cannot be moved to the release position, and the rotation of the take-up hub 92 remains blocked, resulting in a serious failure that the magnetic tape cannot be fed. Regarding the inclination of the brake arm 93,
As shown in JP-A-13798, this can be improved by providing a thin portion in the vicinity thereof, but such an effect cannot be achieved if the boundary is inclined.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is intended to prevent the brake arm from tilting inward.
An object of the present invention is to provide a magnetic tape cassette capable of preventing deformation of a brake member and ensuring smooth operation of the brake member.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-described problems, the present invention is directed to a housing for accommodating a pair of winding hubs wound with a magnetic tape, the portion being stretched between the pair of winding hubs. The lid is joined together to expose only the magnetic tape,
An upper half and a lower half forming a cassette case are rotatably supported between a closed position covering the exposed portion of the magnetic tape and an open position exposing the magnetic tape, and a protrusion is formed on the inner side wall. And engaging the front lid spring-biased to the closed position with a gear provided on the winding hub to inhibit rotation of the winding hub and release the engagement with the gear. A long strip-shaped horizontal plate portion having a braking piece that allows rotation of the winding hub by doing so, and a brake arm vertically erected at both longitudinal ends of the horizontal plate portion, A plate-like horizontal plate portion, a magnetic tape cassette including a central portion having a thick portion and a brake member having an outer portion having a thin portion up to the base of the brake arm, wherein a horizontal portion of the brake member is provided. Near the boundary between the thick and thin parts of the plate The surface on which the brake arm is erected of the thin-walled portion, to provide a magnetic tape cassette, characterized in that a recess extending in the front-rear direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magnetic tape cassette according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a perspective exploded view showing a schematic configuration of a magnetic tape cassette according to this embodiment. The magnetic tape cassette mainly comprises an upper half 10 and a lower half 12,
Meanwhile, the winding hub 14a on the supply side and the winding hub 1 on the winding side
4b is accommodated therein.
On the front side of the upper half 10, a front lid 18 for covering and protecting the magnetic tape 16 when the cassette is not used is rotatably mounted around a support shaft 18a. Further, a slider 20 is attached to the outer lower surface of the lower half 12 so as to cover the open portion on the lower side of the case and to improve the sealing performance so as to be slidable in the front-rear direction.

When the cassette is not used, the winding hubs 14a, 1
A brake member 22 is attached to the upper half 10 to prevent the magnetic tape 16 wound around 4b from becoming loose. The brake member 22 includes two braking pieces 22a and 22b.
And engages the braking piece 22a with a gear 15a provided on the upper portion of the supply-side winding hub 14a.
2b is engaged with a gear 15b provided above the winding hub 14b on the winding side, so that the winding hubs 14a, 14b are engaged.
b, the rotation of the magnetic tape 16 is prevented. The brake member 22 is moved by a brake spring 24
When the cassette is not used, the brake pieces 22a and 22b are biased to positions where they are engaged with the gears 14a and 14b, respectively. The brake spring 24 is locked on a projection 10 a provided on the upper half 10.

The lower half 12 has a rectangular bottom surface 12a.
And a reel shaft insertion hole 12b for inserting the reel shaft into the cassette case when the cassette is used, and a projecting portion 12 extending forward from both left and right ends of the bottom surface 12a.
c, 12c. Left and right overhang 1
2 c and 12 c are provided with cylindrical ribs 12 d and 12 d for guiding the magnetic tape 16. The space between the left and right overhangs 12c, 12c is a space into which a so-called tape loading device provided on the deck side in which the magnetic tape cassette is loaded enters.

The slider 20 is mounted on the bottom surface 12 of the lower half 12.
a, and slides in the front-rear direction of the cassette, but when positioned forward, the space between the left and right overhanging portions 12c of the lower half 12 and the reel shaft insertion hole 12b
Is closed by the bottom surface 20a of the slider 20 for dust prevention. When the slider 20 is located rearward, the space between the left and right overhangs 12c, 12c is released, and two holes 20b, 20b formed on the bottom surface 20a of the slider 20 are inserted into the reel shaft. Hole 12
b, 12b. Slider 20
When the cassette is mounted on the deck, the cassette is automatically positioned rearward by the action of the device in the deck, but when the cassette is not used, the biasing means (leaf spring 26) provided on the lower half 12 moves forward. Is located.

Two split-tube-shaped ribs are formed continuously on the bottom surface 12a of the lower half 12 perpendicularly to the side facing the space between the left and right overhangs 12c, 12c (the side where the magnetic tape is exposed). A wall-shaped member 12e provided in a U-shape is erected. The U-shaped curved portion of the wall-shaped member 12e has a shape that follows the magnetic tape 16 wound around the winding hubs 14a and 14b when the magnetic tape 16 is placed thereon. Then, a columnar rib 12g is disposed substantially perpendicularly to a substantially central portion of a bottom portion 12f divided into a triangular shape by a wall-shaped member 12e.
Is erected. A leaf spring 26 for urging the slider 20 forward is fitted between the columnar rib 12g and the wall-like member 12e. Also, the slider 20
Is biased by a leaf spring 26 to be fixed at a front position when the cassette is not used.
A vertical rib 20c is provided in front of the bottom surface 20a to receive the urging force.

FIG. 2 shows the details of the upper half 10 and the brake member 22. FIG. 2 is a perspective view showing the upper half 10 and the brake member 22 of FIG. 1 upside down, with the other side facing forward. When the upper half 10 and the lower half 12 are joined, a protrusion 10a for fixing the brake spring 24 is provided at a position of the bottom surface 10b of the upper half 10 corresponding to the position of the rib 12g of the lower half 12, and both sides thereof , Wall-shaped ribs 10c are erected. The ribs 10c, 10c are ribs 1 of the lower half 12.
It corresponds to a 2g stepped shape. Also, the ribs 10c,
Ribs 10d, 10d are provided on both sides of 10c. When the upper half 10 and the lower half 12 are joined, the rib 10d is in contact with the wall-like member 12e of the lower half 12 to increase the rigidity of the case.

The brake member 22 includes a winding hub 14a, 1
Brake pieces 22a, 2 engaged with the gears 15a, 15b
The horizontal plate 22c has a long horizontal plate portion 22c, and a brake arm 23 is provided vertically at both ends in the longitudinal direction of the horizontal plate portion 22c. The brake arm 23 includes a leg 23a provided vertically to the horizontal plate 22c, and an arm 23b extending from the leg 23a vertically and horizontally in the longitudinal direction of the horizontal plate 22c. A hook 23 at the tip of the arm 23b which engages with the projection of the front lid 18.
c and a substantially L-shaped contact portion 23d are provided.

In this embodiment, in order to prevent the brake arm 23 from tilting inward, a thin portion of the brake arm 2 is provided near the boundary between the thick portion and the thin portion of the horizontal plate portion 22c.
A concave portion (groove, slit) 22g is provided in the front-rear direction on the surface on which the 3 is erected, so as to release the stress at the time of resin solidification. Further, a similar slit 22f may be provided at the root of the brake arm 23. However, the slit 22f at the base of the brake arm 23
Need not necessarily be provided.

FIG. 3 shows the brake member 22 in an enlarged manner.
FIG. 3A is a plan view, and FIG. 3B is a front view. FIG.
As shown in (b), the horizontal plate portion 22 of the brake member 22
The center of “c” connects the brake member 22 to the winding hubs 14a, 14b.
A thick portion 22d is formed to receive the brake spring 24 for biasing the outer portion, and a thin portion 22e is formed outside the thick portion 22d.
It has become. As shown in FIG. 3A or 3B, the thick portion 22d of the horizontal plate portion 22c of the brake member 22
A recess 22g is provided on the inner surface of the thin portion 22e in the front-rear direction (width direction) near the boundary between the thin portion 22e and the horizontal plate portion 22c at the base of the brake arm 23.
Is provided with a slit (groove) 22f in the width direction.

FIG. 4 is an enlarged view of a portion surrounded by a broken line C in FIG. 3B, and FIG. 5 is an enlarged view of a portion surrounded by a broken line D in FIG. 3B. Show. When the resin is solidified at the time of molding, since the solidification speed is different between the thick portion 22d and the thin portion 22e, the thin portion 22e solidifies first, and then when the thick portion 22d solidifies, the thick portion 22d shrinks. Although a stress is generated that pulls the thin portion 22e inward, the slit 22f or the concave portion 22g is provided inside the horizontal plate portion 22c of the brake member 22, so that the pulling force of the thin portion 22e is cut off, and the braking force is reduced. Arm 23
Can be prevented from tilting.

The sectional shape of the slit 22f or the concave portion 22g is not limited to a trapezoid as shown in FIGS. 4 and 5, but may be a semicircle. The method for forming these slits and grooves such as recesses is not particularly limited, and may be formed using an ejector pin (projection pin) at the time of molding, or may be another method.

As described above, according to the present embodiment, since the concave portion is provided in the thin portion of the horizontal plate portion of the brake member, the tilting of the brake arm can be prevented, and the front lid attempts to move the brake member. In this case, the brake member can be reliably moved without swinging. As described above, the magnetic tape cassette of the present invention has been described in detail.
The present invention is not limited to the above examples, and various improvements and changes may be made without departing from the spirit of the present invention.

[0026]

As described above, according to the present invention, since the concave portion is provided in the thin portion of the horizontal plate portion of the brake member, the brake arm can be prevented from tilting, and the front lid moves the brake member. When trying to do so, it is possible to reliably move the brake member without swinging.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a schematic configuration of a magnetic tape cassette according to the present invention.

FIG. 2 is a perspective view showing the details of the upper half and the brake member of FIG.

FIG. 3A is an enlarged plan view showing a brake member of the present embodiment, and FIG. 3B is a front view thereof.

FIG. 4 is an enlarged view of a portion denoted by reference numeral C in FIG. 3 (b).

FIG. 5 is an enlarged view of a portion denoted by reference numeral D in FIG.

FIG. 6 is a perspective view showing a conventional brake member.

FIG. 7 is a plan view showing the operation of a conventional brake member.

8 (a), (b), and (c) are side views showing the functions of a conventional front lid and a brake member, respectively.

FIG. 9 is a front view of a brake member showing a problem of a conventional brake member, (a) is a front view thereof, and (b) is an enlarged view of a right half thereof.

[Explanation of symbols]

 Reference Signs List 10 Upper half 12 Lower half 14a Supply-side take-up hub 14b Take-up-side take-up hub 15a, 15b Gear 16 Magnetic tape 18 Front lid 20 Slider 22 Brake member 22a, 22b Brake piece 22c Flat plate part 22d Thick part 22e Thin part 22f Slit (at base of brake arm) 22g (at thin portion) 23 Brake arm 23a Leg 23b Arm 23c Hook 23d Contact portion 24 Brake spring 26 Leaf spring

Claims (1)

[Claims] 1. A pair of winding hubs each having a magnetic tape wound thereon are housed, and are coupled in a lid-like manner so as to expose only a portion of the magnetic tape stretched between the pair of winding hubs. An upper half and a lower half forming a cassette case, rotatably supported between a closed position covering the exposed portion of the magnetic tape and an open position exposing the magnetic tape, and having a projection on the inner side wall. A front cover that is spring-biased to the closed position, and engages with a gear provided on the winding hub to inhibit rotation of the winding hub and release engagement with the gear. A long strip-shaped horizontal plate portion having a braking piece that allows rotation of the winding hub by doing so, and a brake arm vertically erected at both longitudinal ends of the horizontal plate portion, The plate-shaped horizontal plate is thick at the center,
A magnetic tape cassette including a brake member having a thin portion at the base of the brake arm, and a thin portion near a boundary between a thick portion and a thin portion of a horizontal plate portion of the brake member. A magnetic tape cassette provided with a concave portion extending in the front-rear direction on a surface on which the brake arm is erected.