JPH0424548Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic tape cassette used in VTRs and the like.

[Conventional technology]

Figures 6 and 7 show conventional magnetic tape cassettes used in household VCRs. Figure 6 is a partially cutaway bottom view of the magnetic tape cassette seen from the lower half side, and Figure 7 is a 6 shows a cross-sectional view of FIG.
The magnetic tape cassette 1 has a cassette body 4 composed of an upper half 2 and a lower half 3 made of synthetic resin, and inside the cassette body 4 are a pair of windings of a magnetic tape 5, a supply reel 6 and a take-up reel 7. times reels are stored. A front cover 8 made of synthetic resin is provided at the front of the cassette body 4 so as to be openable and closable, and covers the magnetic tape 5 fed out from the supply reel 6 to the front surfaces of the tape guide sections 4a, 4a.

This front lid 8 is formed in a U-shape in plan with side plates 8c, 8c extending on both sides of a front plate 8a and a top plate 8b.
A rotation support shaft 9 protruding from the inside of both side plates 8c, 8c,
10 is mounted by being pivotally supported in a shaft hole drilled in the front side of the side wall of the upper half 2, and the long shaft rotation support shaft 9 has a helical winding that biases the front lid 8 into the closed state. A shaped spring 11 is locked.

The spring 11 is formed by bending a wire rod having spring properties, and has a coil portion 11a.
was fitted onto the rotation support shaft 9, one end 11b was locked to a locking pin 12 protruding from the rotation support shaft 9, and the other end 11c having a substantially linear shape was formed on the inner surface of the upper half 2. The front cover 8 is assembled to the upper half 2 by being slidably pressed into the guide groove 13, and both halves 2 and 3 are screwed together with screws 14 to form the cassette body 4.
The front lid 8 is always biased in the closing direction by the torsion force.

However, this spring 11
The rotation support shaft 9 of 1a is fitted externally, and the rotation support shaft 9
Since one end 11b is locked to a locking pin 12 protruding from the spring 11, it is troublesome to assemble the spring 11.
Furthermore, since the pivot shaft 9 had the locking pin 12, the structure of the molding die was complicated.

Therefore, as disclosed in JP-A-60-119680, a slit is formed in the pivot shaft of the front cover from its tip to its base, and both or one of the opposing surfaces of the slit are formed. An engaging recess wider than the slit is formed from one side edge to the other by stealing the flesh at the back of the slit, and the coil part of the helical spring made of wire is externally fitted onto the rotation support shaft. In addition, there is one in which one linear end is engaged with the engagement recess.

[Problem that the invention attempts to solve]

However, in the above-mentioned rotational support shaft, an engagement recess that is wider than the slit is formed in the deep part of the slit, so its strength is weakened and the cross-sectional area changes significantly at the engagement recess. This resulted in poor resin flow during molding, resulting in defective products. Furthermore, since the spring is made of wire and has a helical shape, it sometimes lacks stability when attached to the rotation support shaft.

Therefore, the purpose of the present invention is to provide a magnetic tape cassette in which the strength of the rotating shaft is maintained, resin flow is good during molding, and a spring is stably attached to the rotating shaft. It is said that

[Means for solving problems]

In order to achieve the above object, the present invention has a cassette main body consisting of an upper half and a lower half. In the magnetic tape cassette, a spring is provided on a pivot shaft of the front cover to always bias the front cover in a closing direction. At the same time, a tapered engagement recess is formed at one side edge of the deep part of one opposing surface of the slit, the spring is formed of a plate spring, and one end of the spring is engaged with the engagement recess. a slit mounting part that is inserted into the slit in succession to the claw part, and a holding part that holds approximately half the circumference of the pivot shaft continuously from the slit mounting part; A pressure contact portion is formed on the other end of the spring to be slidably pressed against the upper half, and a curved portion that bulges toward the lower half is formed between the holding portion and the pressure contact portion. It is characterized by having a section.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

A slit 16 is formed in the rotation support shaft 15 of the front lid 8, extending from the tip 15a to the base end 15b, and one opposing surface 1 of the slit 16 is formed.
A tapered engagement recess 17 is formed at one side edge of the inner part of the recess 6a.

A spring 18 attached to the pivot shaft 15 and biasing the front cover 8 to the closed state is attached to the engagement recess 17.
It is formed from a leaf spring with approximately the same width as the width of the . One end side of the spring 18 includes a claw portion 18a at the tip that engages with the engagement recess 17, a slit mounting portion 18b that is inserted into the slit 16 continuously from the claw portion 18a, and the slit mounting portion. A holding part 18 that holds approximately half the circumference of the rotation support shaft 15 continuously from 18b.
c is formed. A pressure contact portion 18d is formed at the other end of the spring 18 and is slidably pressed against the upper half 2. Further, the spring 18 is connected to the holding portion 18c and the pressure contact portion 18.
A curved portion 18e that bulges toward the lower half 3 is provided between the lower half 3 and the lower half 3.

The spring 18 has a curved portion 18e.
Holding portion 18c bulges toward the lower half 3 side.
holds approximately half the circumference of the rotation support shaft 15, inserts the slit mounting part 18b into the slit 16, and inserts the claw part 18a into the slit 16.
is engaged with the engagement recess 17 and is prevented from coming off from the rotation support shaft 15, and the left and right sides of the press-contact part 18d are guided by guide grooves 19 formed on the inner surface of the upper half 2, and the press-contact part 18d is The distal end surface is brought into contact with the locking protrusion 20 of the upper half 2 and is supported by the upper half 2 in pressure contact.

Furthermore, a front lid locking member 21 is provided at a corner of the lower half 3 corresponding to the mounting position of the spring 18 to lock the front lid 8 in a closed state when not in use. This front lid locking member 21 has support shafts 2 on both sides of the upper part.
1a and 21a are rotatably suspended from the ribs 3a and 3a of the lower half 3, and the protrusion 21b is pushed by the curved portion 18e of the spring 18 to lock the front lid 8 from the side wall of the lower half 3. The locking protrusion and the front cover 8
A release protrusion is protruded to release the lock from the lock.

A magnetic tape cassette constructed in this way is
When the VTR device is loaded, the working claw of the VTR device pushes the release protrusion of the front cover locking member 21 to release the locking between the front cover locking member 21 and the front cover 8, and another working claw pushes the front cover locking member 21 and the front cover 8. Open the lid 8 by rotating it upward in FIG.

As a result, the rotation support shaft 15 of the front cover 8 rotates clockwise in FIG. The pressure contact portion 18d slides on the inner surface of the upper half 2 and retreats toward the rotation support shaft 15 side.

When the magnetic tape cassette is removed from the VTR device, the pivot shaft 15 is rotated counterclockwise in FIG. 3 due to the restoring force of the spring 18, and the front cover 8 is returned to the closed position. The locking member 21 is pushed by the curved portion 18e, and the locking protrusion engages with the front lid 8, so that the front lid 8 is held in the closed state.

Since the magnetic tape cassette according to this embodiment is constructed as described above, the spring 18 that biases the front cover 8 in the closed state is prevented from coming off by the rotation support shaft 15 and is stably mounted. , works reliably,
A magnetic tape cassette of stable quality can be obtained at low cost.

[Effect of idea]

As described above, the present invention forms a slit extending from the distal end to the proximal end on the pivot shaft of the front cover that covers the front surface of the cassette main body, and also forms a slit on the inner side of one of the opposing surfaces of the slit. A tapered engagement recess is formed on the edge, a spring that always biases the front cover in the closing direction is formed of a leaf spring, and one end of the spring has a claw portion at the tip that engages with the engagement recess. , forming a slit mounting part that is inserted into the slit continuously from the claw part, and a holding part that holds approximately half the circumference of the rotation support shaft continuously from the slit mounting part; A pressure contact portion is formed on the other end side to be slidably pressed against the upper half, and a curved portion that bulges toward the lower half is provided between the holding portion and the pressure contact portion. The strength of the pivot shaft is maintained, and due to the tapered engagement recess, there is little change in the cross-sectional area of the pivot shaft, and the flow of resin during molding is good, reducing the occurrence of defective products. Moreover, since the spring is a leaf spring, it can be stably attached to the rotation support shaft.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the present invention. Figure 1 is a perspective view of the spring and front cover pivot shaft, and Figure 2 is a schematic diagram of the upper half viewed from the inside. Figure 3 is a cross-sectional view of Figure 2, Figure 4 is a cross-sectional view of Figure 2,
The figure is a plan view of the rotation support shaft viewed from the upper half side.
The figure is an enlarged view of the main part of FIG. 3, FIGS. 6 and 7 show a conventional example, FIG. 6 is a bottom view of the magnetic tape cassette, and FIG. 7 is a cross-sectional view taken along the line shown in FIG. 1... Magnetic tape cassette, 2... Upper half,
3...lower half, 4...cassette body, 5...magnetic tape, 6...supply reel, 7...take-up reel, 8...front cover, 15...rotation shaft, 15a...
Tip, 15b... Base end, 16... Slit, 16
a... One opposing surface, 17... Engaging recess,
18...Spring, 18a...Claw portion, 18b...
...Slit attachment part, 18c...Holding part, 18d...
... Pressure contact portion, 18e... Curved portion.

Claims (1)

[Scope of utility model registration request] A magnetic tape 5 is unwound from a pair of winding reels 6 and 7 housed in a cassette body 4 consisting of an upper half 2 and a lower half 3 to the front of the cassette body 4.
A front lid 8 covering the front lid 8 is pivotally supported on the upper half 2 so as to be openable and closable,
In the magnetic tape cassette 1, the rotation support shaft 15 of the front cover 8 is provided with a spring 18 that always biases the front cover 8 in the closing direction. A tapered engagement recess 17 is formed at one side edge of the inner side of one opposing surface 16a of the slit 16, and the spring 18 is formed of a plate spring. On one end side, a claw portion 18a at the tip that engages with the engagement recess 17;
a slit mounting part 18b that is inserted into the slit 16 continuously from 8a; and the slit mounting part 18b.
A holding part 18c is formed continuously to hold approximately half the circumference of the rotation support shaft 15, and a pressure contact part 18d is formed on the other end side of the spring 18 to slidably press against the upper half 2. A magnetic tape cassette characterized in that a curved portion 18e bulging toward the lower half 3 is provided between the holding portion 18c and the pressing portion 18d.