JPH0554594A - Production of video tape cassette - Google Patents

Abstract

PURPOSE:To obtain the process for production of the video tape cassette which is simple in an assembly operation and can attain a cost reduction. CONSTITUTION:A slit 31b for mounting a front cap spring 32 to a turning shaft 31a is formed in the drawing direction of a front cap forming mold 23 at the time of molding the front cap 31. The front cap spring 32 is formed of a leaf spring and is provided with a stationary end 32a, a curved part 32b and a free end 32c. This front cap spring 32 is mounted by mounting the stationary end 32a on the turning shaft 31a in such a manner that the curved part 32b bulges to a lower half 5 side. The front cap 31 is assembled to the upper half 4 to bring the free end 32c into pressurized contact slidably with the upper half 4. The curved part 32b is brought into pressurized contact with the part 33b to be pressurized to energize a front cap detaining member 33 in a front cap detaining direction. The upper half 4 and a lower half 5 are then fixed by means of screws 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a video tape cassette.

[0002]

2. Description of the Related Art FIGS. 4 to 6 relate to a conventional video tape cassette used in a home video tape recorder or the like. FIG. 4 is a partially cut bottom view of the video tape cassette viewed from the lower half side. 5 and 5 are sectional views taken along line VV of FIG. 4, and FIG. 6 is a plan view of a lower half corner portion corresponding to the cutout portion of FIG.

In the video tape cassette 1, a spiral front cover spring 3 is mounted on a rotary support shaft 2a of the front cover 2, and the front cover 2 is attached to the upper half 4 and a magnetic tape is attached to the lower half 5. A winding reel 7 for supply and a winding reel 8 for winding the tape 6 are accommodated, and the magnetic tape 6 is fed to the front surface of the tape guide portions 5a, 5a of the lower half 5, and A coiled front lid locking spring 10 is attached to the support shaft 9a of the lid locking member 9, the front lid locking member 9 is assembled to the lower half 5, and the upper half 4 and the lower half 5 are connected to each other. It is manufactured by fixing with screws 11.

[0004]

However, the front lid 2
In order to mount the spiral front lid spring 3 that biases the front lid 2 in the closing direction on the rotary support shaft 2a,
A locking projection 2b for locking the front lid spring 3 is formed integrally with the rotation support shaft 2a at the time of molding the front lid 2. The locking projection 2b is formed on the peripheral surface of the rotation support shaft 2a. Since it protrudes in a direction different from the drawing direction of the split mold for molding the rotation support shaft 2a, a separate split mold for molding the locking projection 2b is separately required, and therefore, the mold for the front lid 2 is formed. Since the whole is composed of a large number of split molds, the structure and operation of the molding mold are complicated, the mold cost is increased, and the productivity is poor.

The coiled front lid spring 3 is
It is formed by bending a wire material having a spring property, and has a fixed portion 3a which is locked to the locking projection 2b at one end and which is externally fitted to the rotary support shaft 2a continuously to the fixed portion 3a. The winding part 3b is slid in a guide groove 4a of the upper half 4 at the tip of the free arm 3c, a bent part 3d abutting the inner surface of the top plate of the upper half 4 in the middle of the free arm 3c continuous to the spiral winding part 3b. Since the sliding contact portion 3e is provided in contact with the sliding contact portion 3e, the shape is peculiar and a processing technique is required, which is disadvantageous in terms of cost.

Moreover, when the front lid spring 3 having a spiral shape is attached to the rotation support shaft 2a of the front lid 2 and the front lid 2 is assembled to the upper half 4, as shown in FIG. Since the bent portion 3d of the spring 3 contacts the inner surface of the top plate of the upper half 4, the spring force of the spiral winding portion 3b is transmitted to the inner surface of the top plate of the upper half 4, and the reaction force thereof causes the front lid 2 to rotate. Support shaft 2a
However, in FIG. 4, it becomes easier to move downward, and the side of the rotation support shaft 2a of the front lid 2 is lifted up from the upper half 4, and the upper half 4 with the front lid 2 and the lower half 5 are assembled. In the pre-assembling step, the front lid 2 is easily removed from the upper half 4, and the assembling work of the upper half 4 and the lower half 5 is troublesome.

Further, since the front lid spring 3 and the front lid locking spring 10 are both in the vicinity of each other, they are required, so that the mounting work is complicated and the cost is disadvantageous. there were.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method of manufacturing a video tape cassette which is easy to assemble and can reduce the cost.

[0009]

In order to achieve the above object, the present invention accommodates an upper half having a front lid with a front support spring attached to a pivot shaft and a winding reel having a magnetic tape wound thereon. In the method for manufacturing a video tape cassette in which the lower half having the front lid locking member attached thereto is fixed with a screw, an axial slit is formed in the pivot shaft at the time of molding the front lid. Direction, the front lid spring is formed of a leaf spring, and a fixed end which is inserted into the slit at one end thereof and embraces the rotation support shaft for substantially a half circumference is formed continuously with the fixed end. A free end is continuously provided on the curved portion, and the front lid spring is mounted on the pivot shaft so that the curved portion bulges to the lower half side, and the front lid spring is mounted. Attach the front lid to the upper half and attach the free end of the front lid spring. When the upper half and the lower half are fixedly slidably contacted with each other and the upper half and the lower half are fixed to each other, the curved portion of the front lid spring is brought into pressure contact with the pressed portion of the front lid locking member, and the front lid engagement is performed. It is characterized in that the stopper member is biased in the front lid locking direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The reference numerals used in FIGS. 4 to 6 are used as necessary.

As shown in FIG. 1, the fixed die 21 and the movable die 2
The front lid 31 is molded on the molding die 23 made of two. At this time, the rotation support shaft 31a of the front lid 31 is fixed to the fixed mold 21 and the movable mold 2.
The rotation support shaft 31a is formed by the two joint surfaces 21a and 22a.
A slit 31b formed in the axial direction of the rotation support shaft 31a at the tip side of the is provided in the direction of arrow A, which is the drawing direction of the movable die 22.

On the other hand, the front lid spring 32 is formed of a leaf spring, and one end thereof has a fixed end 32a which is inserted into the slit 31b and holds the rotary support shaft 31a for a half circumference. The curved portion 32b is continuously connected to the curved portion 32
A free end 32c is provided continuously to b.

The fixed end 32a of the front lid spring 32 is attached to the rotary support shaft 31a so that the curved portion 32b bulges toward the lower half 5 side (downward in FIG. 3). The front lid 31 attached with is attached to the upper half 5. As a result, the free end 32c of the front lid spring 32 is guided to the left and right by the guide groove 4a formed on the inner surface of the upper half 4, and the tip end surface is brought into contact with the locking projection 4b of the upper half 4 so as to contact the upper half 4. 4 is pressed and supported.

The lower half 5 accommodates the winding reels 7 and 8 around which the magnetic tape 6 is wound, and the front lid locking member 3 is provided at a corner opposite to the mounting portion of the front lid spring 32.
Assemble 3. The front lid locking member 33 is provided on the both sides of the upper part at the time of fixing the support shafts 33a, 33a rotatably suspended by the ribs 5b, 5b of the lower half 5 and the upper half 4 to the lower half 5. The pressed portion 33b against which the curved portion 32b of the lid spring 32 is pressed, and the locking portion that protrudes from the side wall of the lower half 5 and locks the front lid 31 when the pressed portion 33b is pressed by the curved portion 32b. It has a protrusion (not shown) and a releasing protrusion (not shown) for releasing the engagement with the front lid 31.

Then, the upper half 4 having the front lid 31 with the front lid spring 32 mounted therein is accommodated with the winding reels 7 and 8 around which the magnetic tape 6 is wound, and the front lid locking member 33.
Is assembled to the lower half 5 and the screws 4 and 5 are fixed by screws 11 to manufacture a video tape cassette.

When the video tape cassette 1 thus constructed is loaded in the VTR device, the working claw of the VTR device pushes the releasing projection of the front lid locking member 33 to move the front lid locking member 33 and the front lid. While the lock of 31 is released, another action claw opens the front lid 31 by rotating it upward in FIG.

As a result, the rotation support shaft 31a of the front lid 31 is rotated clockwise in FIG. 3, the front cover spring 32 is wound around the rotation support shaft 31a, and the bending portion 32b is located on the upper half 4 side. It retreats slightly and the free end 32c is the upper half 4
It slides on the inner surface of and is retracted to the side of the rotation support shaft 31a.

Then, the video tape cassette 1 is connected to the VTR.
When it is taken out from the device, the restoring force of the front lid spring 32 causes the rotation support shaft 31a to rotate in the direction opposite to the opening direction motion, and the free end 32c advances to the side opposite to the rotation support shaft 31a. Then, the front lid 31 returns to the closed position, and the front lid locking member 33 is
The curved portion 32b of the front lid spring 32 presses the pressed portion 33b.
Is pressed and pushed, the locking projection engages with the front lid 31, and the front lid 31 is held in the closed state.

As described above, in this embodiment, since the slit 31b for mounting the front lid spring 32 is formed in the removing direction of the movable die 22, a dedicated molding die for molding the slit 31b is required separately. In addition, the structure and operation of the entire forming die of the front lid 31 are simplified, the die cost is reduced, and the productivity is improved.

The front lid spring 32 is a leaf spring, and is connected to the fixed end 32a, which is inserted into the slit 31b at one end thereof and holds the rotary support shaft 31a substantially half around, and the fixed end 32a. Since the curved portion 32b and the free end 32c that is continuous with the curved portion 32b are integrally formed, the shape is simple and the processing technique is not required so much, so that the cost can be reduced.

Moreover, the front lid spring 32 is attached to the rotary support shaft 3
When the front lid 31 attached to 1 a is assembled to the upper half 4, the spring force of the curved portion 32 b of the front lid spring 32 causes the fixed end 32 to move.
Since the rotation support shaft 31a and the inner surface of the upper half 4 are approximately averaged through the a and the free end 32c, the front lid 31 is securely attached to the upper half 4 and is difficult to come off, and the upper half 4 and the lower half 4 are not easily separated. Assembly work with the half 5 becomes easy.

Further, since the front lid spring 32 also functions as a front lid locking spring, the mounting work can be simplified and the cost can be reduced.

[0023]

INDUSTRIAL APPLICABILITY As described above, according to the present invention,
A slit for mounting the front lid spring is formed on the pivot shaft of the front lid in a direction of removing the front lid molding die, and the front lid spring is a leaf spring and is inserted into the slit at one end of the front lid spring. A fixed end that holds the shaft about half the circumference, a curved portion that is continuous with the fixed end, and a free end that is continuous with the curved portion are formed, and the front lid spring is formed such that the curved portion bulges toward the lower half side. So that the fixed end is attached to the rotary support shaft, the front lid is assembled to the upper half, and the free end of the front lid spring is slidably pressed against the upper half. When the winding reel wound around the front cover spring is housed and the lower half having the front cover locking member assembled is fixed, the curved portion of the front cover spring is pressed against the pressed portion of the front cover locking member. Let me
Since the front lid locking member is biased in the front lid locking direction and the upper half and the lower half are fixed with screws, a separate split mold for molding the slit for mounting the front lid spring is separately provided. It is not necessary, and the structure and operation of the entire front die are simplified, the die cost is low, and the productivity is improved.

Further, the front lid spring is a leaf spring, and is inserted into the slit at one end thereof so that the pivot shaft 31a is rotated.
Since the fixed end that holds the semicircle for about half a turn, the curved portion that is continuous with the fixed end, and the free end that is continuous with the curved portion are integrally formed, the shape is simple and processing technology is not required so much. The cost can be reduced.

Moreover, when the front lid in which the front lid spring is mounted on the rotation support shaft is assembled to the upper half, the spring force of the curved portion of the front lid spring is rotated through the fixed end and the free end. Since the inner surfaces of the support shaft and the upper half are approximately averaged, the front lid is securely attached to the upper half and is hard to come off, and the assembling work of the upper half and the lower half becomes easy.

Further, since the front lid spring also functions as a spring for locking the front lid, the mounting work thereof is simplified,
And the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing molding of a front lid.

FIG. 2 is a cross-sectional bottom view of a main part of the upper half viewed from the inner surface side.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a partially cutaway bottom view of the video tape cassette seen from the lower half side.

5 is a cross-sectional view taken along line VV of FIG.

6 is a plan view of a lower half corner portion corresponding to the cutout portion of FIG. 4. FIG.

[Explanation of symbols]

1 ... video tape cassette, 4 ... upper half, 5 ... lower half, 6 ... magnetic tape, 7 ... winding reel for supply, 8 ... winding reel for winding, 21 ... fixed type, 22 ... movable type, 23
... Mold, 31 ... Front lid, 31a ... Rotating support shaft, 31b ... Slit, 32 ... Front lid spring, 32a ... Fixed end, 32
b ... curved portion, 32c ... free end, 33 ... front lid locking member, 3
3b ... Pressed portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Okubo 801 Nakatetsu, Tamabo-cho, Nakakoma-gun, Yamanashi Prefecture Konica Magnetics Co., Ltd.

Claims (1)

[Claims] 1. A winding reel in which a magnetic tape (6) and an upper half (4) having a front lid (31) having a front lid spring (32) mounted on a pivot shaft (31a) are assembled. (7) In the manufacturing method of the video tape cassette (1) in which (8) is housed and the lower half (5) with the front lid locking member (33) assembled is fixed with screws (11), At the time of molding (31), an axial slit (31b) is formed in the rotary support shaft (31a) in the removal direction of the front lid molding die (23), and the front lid spring (32) is a leaf spring. Formed, and is inserted into the slit (31b) at one end of the rotary support shaft (3
1a) holding the fixed end (32a) for about half a turn, the fixed end (32a)
The curved portion (32b) is continuously connected to the curved portion (32b), the free end (32c) is continuously provided to the curved portion (32b), and the front lid spring (32) is attached to the lower half (5) of the curved portion (32b). Attach the fixed end (32a) to the rotation support shaft (31a) so that the front cover spring (3a)
Assemble the front lid (31) equipped with 2) to the upper half (4), and slidably press the free end (32c) of the front lid spring (32) to the upper half (4). When fixing the half (4) and the lower half (5), the curved portion (32b) of the front lid spring (32)
Is pressed against the pressed portion (33b) of the front lid locking member (33) to bias the front lid locking member (33) in the front lid locking direction. Tape cassette manufacturing method.