JPH0356927Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention is ideal for application to tape cassettes for video tape recorders, for example, and uses a locking member with an integrally formed spring portion. The present invention relates to a tape cassette in which the front lid of the cassette housing is locked in a closed state.

[Summary of the idea]

In the present invention, a lock member is movably attached to the cassette casing, a spring part having a flexible arc-shaped part is integrally molded from synthetic resin, and the free end of the spring part is attached to the cassette casing. The front cover, which is rotatably attached to the cassette case, can be held in the closed state by elastically abutting the spring contact surface of a rib provided on the body and moving the locking member forward by the elasticity of the spring. In a tape cassette that is configured to release the lock in the closed state of the front cover by moving the locking member back against the elasticity of the spring, the spring In order to prevent the middle part between the free end of the spring part and the arcuate part from coming into contact with the spring abutting surface of the rib, the slope is gradually spaced away from the middle part of the spring part as it approaches the arcuate part. By forming the surface on the spring abutting surface of the rib, when the locking member is moved back, the effective length of the spring section that exerts elasticity is shortened, and at the same time, the arcuate section is prevented from bending at a steep angle. This is designed to prevent this from happening.

[Conventional technology]

The conventional technology for this type of tape cassette is
There is a technique disclosed in Japanese Utility Model Publication No. 58-34623.
Therefore, this conventional example will be explained based on FIGS. 3 to 5.

First, in FIG. 3, a pair of left and right reels 5 on which tape 4 is wound are rotatably stored in a cassette housing 3 consisting of upper and lower halves 1 and 2, and the tape 4 is guided by a pair of left and right tape guides 6. It is guided and stretched along the front opening 7 of the cassette housing 3. The front opening 7 is opened by a front cover 9 rotatably attached to the cassette housing 3 by a hinge 8.
The front cover 9 is disposed inside the front wall 3a of the cassette housing 3 and is configured to be locked in the closed state by a locking member 11.
The lid 9 is urged to close by a spring (not shown).

Next, as shown in FIG. 4, the lock member 11 is
A main body 12 having a substantially rectangular frame shape, a lock portion 13 at one end, and a spring portion 14 at the other end are integrally molded from synthetic resin. The spring portion 14 has a flexible arc-shaped portion 14a, and is approximately U-shaped from the fixed end 14b to the free end 14c, and is formed so as to exhibit elasticity as a whole. Also, the spring part 14
A plurality of arc-shaped protrusions 15 are formed on the surface. The locking member 11 is attached to the front wall 3a of the cassette housing 3.
A spring portion is provided on the spring abutment surface 17a of the rib 17, which is disposed slidably left and right (in the directions of arrows a and b) between the lower half 2 and the vertical wall 16 in the cassette housing 3, and is integrally formed with the lower half 2. The free ends 14c of 14 are elastically abutted.

Therefore, the locking member 11 is normally moved forward in the direction of the arrow a as shown by the dashed line by the elasticity of the spring portion 14, and the locking portion 13 of the locking member 11 is moved approximately toward the rear surface of the front cover 9. By being engaged with the L-shaped locked portion 18, the front lid 9 is locked in the closed state.

When the tape cassette is installed in the video tape recorder, the front wall 3a of the cassette housing 3
The lock release pin 20 is inserted into the pin insertion hole 19 (see Fig. 3) provided in the lock member 11, and the lock release pin 20 presses the slope 21 formed on the main body 12 of the lock member 11, thereby releasing the lock member. 11 is moved back in the direction of arrow b, as shown by the solid line, against the elasticity of the spring portion 14. As a result, the locking member 1
The first locking portion 13 is removed from the locked portion 18 of the front cover 9, and the front cover 9 is unlocked in the closed state.

[Problem that the invention attempts to solve]

However, the conventional tape cassette described above has the following problems.

That is, as shown in FIG. 5, the rib 17 with which the free end 14c of the spring portion 14 of the locking member 11 is elastically abutted prevents the free end 14c of the spring portion 14 from moving even if vibration or the like is applied to the tape cassette. In order to prevent the rib 17 from being accidentally climbed over, a certain level of height _H1 is required. The conventional rib 17 has a spring contact surface 17a that is substantially vertical.

Therefore, when the lock member 11 is moved back in the direction of arrow b as shown by the solid line against the elasticity of the spring portion 14, the spring portion 14 moves between its free end 14c and the arc-shaped portion 14.
It comes into contact with the spring contact surface 17a of the rib 17 over a large range up to the intermediate portion 14d between the rib 17 and the rib 17a. Due to this contact, the effective length of the spring portion 14 that exhibits elasticity is in the forward movement state shown by the dashed line.
At the same time, the arcuate portion _14a is bent at a steep angle and the bending radius of the arcuate portion 14a becomes _R1 in the forward movement state _.
It becomes significantly smaller from R to ₂ in the reciprocating state. As a result, when the locking member 11 moves back, a large stress is concentrated on the arcuate portion 14a, which is a part of the spring portion 14, and the strain increases as time passes while the locking member 11 is in the back-moving state, which is called creep. It was becoming a problem.

In particular, since the locking member 11 is moved back when the tape cassette is installed in a high-temperature video tape recorder, creep occurs significantly in this high-temperature environment, and the predetermined elastic force of the spring portion 14 Not only would it not be possible to obtain this, but the repeated reciprocation of the locking member 11 would lower its fatigue limit, and in some cases there was a risk that the spring portion 14 would be damaged.

Therefore, the present invention is designed to prevent the arcuate portion from bending at a steep angle at the same time as the effective length of the spring portion that exhibits elasticity becomes shorter when the lock member is moved back. be.

[Means for solving the problem] The present invention provides the above-mentioned tape cassette.
An inclined surface is formed at a portion of the spring contacting surface of the rib that faces the intermediate portion between the free end of the spring portion and the arc-shaped portion, and this inclined surface is on the arc-shaped portion side with respect to the intermediate portion of the spring portion. The spring portion is formed into an inclined surface that is gradually spaced apart from the intermediate portion as the locking member reaches , and the angle of inclination of this inclined surface is set to be smaller than the inclination angle of the intermediate portion of the spring portion due to the backward movement of the locking member. It is something that is.

[Effect]

In the present invention, since an inclined surface is formed on the spring abutting surface of the rib, when the locking member is moved back and the spring portion is bent, the intermediate portion between the free end of the spring portion and the arcuate portion is not contacted by the spring contact surface of the rib. Therefore, the effective length of the spring portion that exhibits elasticity does not change at all from the forward movement state, and the arcuate portion is not bent at a steep angle. As a result, it is possible to prevent large stress from being concentrated on the arcuate portion that is a part of the spring portion when the lock member moves back.

〔Example〕

An embodiment in which the present invention is applied to a tape cassette for a video tape recorder is shown in Figs. 1 and 2 below.
This will be explained based on the diagram. In addition, the above-mentioned [prior art]
Components that are the same as those in the conventional example described in section 2 will be designated by the same reference numerals, and their explanation will be omitted.

In the present invention, the spring contact surface 17a of the rib 17 integrally formed with the lower half 2 is connected to the free end 14c of the spring portion 14 of the lock member 11 and the arcuate portion 14a.
An inclined surface 23 is formed at a portion facing the intermediate portion 14d. This inclined surface 23 is the locking member 1
1, that is, the intermediate portion 14 of the spring portion 14 as it approaches the arcuate portion 14a with respect to the intermediate portion 14d of the spring portion 14.
It is inclined so as to gradually move away from d. Further, in this embodiment, the portion of the spring contact surface 17a of the rib 17 facing the free end 14c of the spring portion 14 is a vertical surface 24 (however, in reality, due to the draft angle for molding, Center plane (in the case shown, the cassette housing 3 to which the rib 17 is attached)
(parallel to the rib mounting surface) is slightly inclined with respect to the vertical direction perpendicular to the rib mounting surface. Next, in this embodiment, the free end 14 of the spring portion 14
A circular projection 25 is formed at c, and this circular projection 25 is elastically abutted against the vertical surface 24 of the rib 17. In this embodiment, the effective length of the spring portion 14 that exhibits elasticity, that is, the length _L3 from the fixed end 14b to the free end 14c, is approximately 38.6 mm, and the reciprocating stroke S of the lock member 11 is approximately 5 mm. It's summery. Further, the height H ₂ of the rib 17 is approximately 10 mm, the height H ₃ of the vertical surface 24 is approximately 3.3 mm, and the inclination angle θ ₁ of the inclined surface 23 is approximately 66°. In this text, the term "angle of inclination" refers to the angle formed by the rib mounting surface of the cassette casing 3 to which the rib 17 is attached.

In the tape cassette constructed as described above, locking and unlocking of the front cover 9 in the closed state by the reciprocating movement of the locking member 11 is performed in substantially the same manner as in the prior art example described above.

However, according to the present invention, the lock member 11 resists the elasticity of the spring portion 14 and moves in the direction indicated by the arrow b as shown by the solid line.
Even if the spring portion 14 is bent to the maximum by moving backward in the direction, the free end 14c of the spring portion 14 and the arcuate portion 14a
The inclination angle θ ₁ of the inclined surface 23 of the rib 17 is smaller than the inclination angle θ ₂ of the intermediate portion 14d with respect to Only the circular protrusion 25 of the rib 17 remains in contact with the vertical surface 24 of the rib 17. Therefore, the effective length of the spring portion 14 that exhibits elasticity
L ₄ does not change at all from L ₃ in the forward movement state shown by the dashed line, and the arcuate portion 14a is not bent at a steep angle, so its bending radius R ₄ hardly changes from R ₃ in the forward movement state. do not. As a result, the lock member 11
The arcuate portion 14a, which is a part of the spring portion 14,
This prevents large stress from concentrating on the spring portion 14, and the entire spring portion 14 can receive elastic force due to the double movement.

Further, according to this inclined surface 23, even if the free end 14c of the spring portion 14 tries to climb over the rib 17 due to vibration or the like being applied to the tape cassette,
Since the circular protrusion 25 of the free end 14c is guided by the inclined surface 23, the free end 14c is smoothly returned to the vertical surface 24 side of the rib 17.

Incidentally, the inclined surface 23 of the rib 17 may be extended as it is to the lower half 2, but in this case, the rib 1
The width W ₁ of the lower end of the lower half 7 increases, and sink marks are likely to occur on the surface of the lower half 2 at the portion where the rib 17 is present when the lower half 2 is molded. Therefore, in this embodiment, the rib 1
By forming the vertical surface 24 on the lower end side of the spring contact surface 17a of the rib 17, the lower end of the rib 17 can be
W ₂ is used to prevent sink marks on the surface of the lower half 2 as much as possible. By the way, when the vertical surface 24 is formed as described above, when the lock member 11 is moved back, the spring portion 14 is at the height of the vertical surface 24.
Although there is a risk of contact with the H ₃ portion, in this embodiment, a circular projection 25 is formed on the free end 14c of the spring portion 14, so that only this circular projection 25 will come into contact with the vertical surface 24. This prevents the spring portion 14 from coming into contact with the height _H3 portion of the vertical surface 24.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and various effective changes can be made based on the technical idea of the present invention.

For example, in the embodiment, the front cover is locked and unlocked by sliding the lock member, but this lock member may also be of a rotating structure, or the lock member may be of a spring type. The portion is not limited to the approximately U-shape shown in the embodiment, but may be S-shaped.
Character shapes etc. are also applicable.

The present invention is not limited to tape cassettes for video tape recorders, but can be applied to tape cassettes for various recording and reproducing devices that record or reproduce various types of information using various recording or reproducing methods.

[Effect of idea]

As described above, according to the present invention, when the locking member is moved back, the effective length of the spring portion that exhibits elasticity is shortened, and at the same time, the arcuate portion is prevented from being bent at a steep angle. As a result, large stress is not concentrated on the arcuate part of the spring part when the locking member moves back, significantly improving creep resistance (especially creep resistance in high temperature environments). I can do it. Therefore, it is possible to prevent the deterioration of the elastic force of the spring part and the decrease in the fatigue limit due to repeated reciprocation of the locking member, and to ensure that the front cover is always locked and unlocked in the closed state. A highly reliable tape cassette is obtained.

Furthermore, according to the inclined surface of the present invention, even if the free end of the spring part rides on the inclined surface due to vibrations etc. applied to the tape cassette, the free end can be smoothly returned to its original position by the inclined surface. Therefore, the elasticity of the spring portion can always be effectively exhibited, and the lock member can reciprocate reliably.

[Brief explanation of drawings]

1 and 2 show an embodiment in which the present invention is applied to a tape cassette for a video tape recorder. FIG. 1 is an enlarged front view showing the operation of the main parts, and FIG. It is a partially cutaway perspective view of the section. 3 to 5 show conventional examples of tape cassettes for video tape recorders, in which FIG. 3 is a perspective view of the tape cassette, FIG. 4 is a partially cutaway front view of the main part, and FIG. FIG. 5 is an enlarged front view showing the operation of the main parts. In addition, in the symbols used in the drawings, 3...Cassette housing, 9...Front cover, 11...Lock member, 13
... Lock part, 14 ... Spring part, 14a ... Arc-shaped part, 14c ... Free end, 14d ... Middle part, 17
. . . Rib, 17a . . . Spring contact surface, 18 . . . Locked portion, 23 . . . Inclined surface.

Claims (1)

[Claims for Utility Model Registration] A locking member 11 is movably attached to the cassette housing 3, and a spring portion 14 having a flexible arc-shaped portion 14a is integrally molded with the locking member 11 from synthetic resin. , a spring contact surface 17 of a rib 17 provided on the cassette housing 3 with the free end 14c of the spring portion 14
The front lid 9, which is rotatably attached to the cassette housing 3, is locked in the closed state by elastically abutting the front lid 9 on the cassette housing 3 and moving the locking member 11 forward by the elasticity of the spring portion 14. , in the tape cassette configured to release the lock of the front lid 9 in the closed state by moving the locking member 11 backward against the elasticity of the spring portion 14, the spring of the rib 17 An intermediate portion 1 between the free end 14c of the spring portion 14 and the arcuate portion 14a at the contact surface 17a.
An inclined surface 23 is formed at a portion facing the spring portion 14, and the inclined surface 23 becomes closer to the arcuate portion 14a with respect to the intermediate portion 14d of the spring portion 14.
Further, the inclination angle of this inclined surface 23 (the angle formed with the rib mounting surface of the cassette casing 3 to which the rib 17 is attached) θ ₁ is determined by the return of the locking member 11 . The inclination angle of the intermediate portion 14d of the spring portion 14 due to the movement (rib 17
A tape cassette characterized in that the tape cassette is set at an inclination angle smaller than θ ₂ (the angle formed by the rib mounting surface of the cassette casing 3 to which the tape cassette is attached).