JPH0528626Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a magnetic tape cassette, and more particularly to a locking mechanism for a front cover of a magnetic tape cassette.

More particularly, the present invention relates to a locking mechanism that occupies less space.

(Prior art and its drawbacks) A magnetic tape cassette used for VHS video, 8mm video, DAT tape, etc. has a case with a front part where the magnetic tape is exposed, and a case that protects the magnetic tape exposed on this front part. For this reason, it is composed of a front lid which is pivotally attached to the main body on both sides of this front part.

The front cover is closed when not in use, such as when storing the cassette, and pivots to open when in use.
When this front cover is closed, it is locked to prevent it from being opened accidentally by external force, and when it is attached to a recorder, it is equipped with a locking mechanism that automatically releases the lock with a lock release pin that comes in from the recorder side. ing.

Several types of locking mechanisms have been proposed, but the typical one, as seen in VHS video cassettes, is a locking mechanism that is pivotable by a bearing or shaft installed in the case orthogonal to the axis of the front cover. A locking protrusion capable of engaging with a locking hole in the front cover is provided near the tip of the rocking plate supported by the front cover, and the rocking plate is always deflected toward the end plate of the front cover by a spring. . When the lock release pin on the recorder side swings this rocking plate, the locking protrusion is disengaged from the locking hole. However, the oscillating plate occupies a relatively large space, so if you want to design a case with as much winding capacity as possible while downsizing the case, the oscillating plate of the locking mechanism should be used as a guide for the magnetic tape running path. There was a limit because it interfered with pins, etc. For example, in the recently put into practical use VHS-C (used for illustrating the present invention), a large hub is used that is close to or even inside the side wall of the case. For this reason, the location where the locking mechanism can be accommodated is limited to the area near the pivot point of the front cover, but since guide rollers, guide pins, etc. are placed in this area, the space for the locking mechanism becomes increasingly limited. Become.

Another type of locking mechanism is shown in U.S. Pat. No. 51-15909. In this example, the locking member is attached to the case body so as to be able to slide toward the front lid at right angles to the pivot axis of the front lid, and is always biased toward the front lid by a spring. When the recorder-side release pin that enters from the bottom surface of the lock member acts on the inclined surface of the lock member, the lock member is disengaged from the front cover. The locking member must be placed far enough back from the magnetic tape to avoid interference with the magnetic tape, and this has a large impact on the internal structure, making it impossible to get a large tape winding hub, and affecting guide pins, etc. There is a problem.

A similar method is also described in Utility Model Application No. 51-51718, but in this example the locking member is provided along the front of the case and slides in the axial direction of the pivot shaft of the front cover. The exposed length of the front magnetic tape is greatly limited.

In order to avoid the complexity of the locking mechanism, it is also possible to directly contact one of the two perpendicular surfaces of the front cover with a sliding rod-shaped member depending on the opening/closing position of the front cover, and press the rear end with a leaf spring. It is. In this case, the front cover is opened and closed by means on the recorder side. However, this method has the disadvantage that since there is no locking mechanism, the front cover can be easily opened by hand or by a small external force when the recorder is removed from the recorder and not in use.

OBJECTS OF THE INVENTION It is an object of the invention to provide a locking mechanism for a front cover that occupies a minimum amount of space in a magnetic tape cassette. The specific purpose of this invention is to provide a locking mechanism for the front cover with a locking lever that can be easily installed in complicated areas such as the tape running path, tape hub, and guide rollers in one corner of the cassette case without interfering with them. The purpose is to establish

(Summary of the invention and its effects) The invention includes a cassette case consisting of an upper case and a lower case, a front cover attached to the front part of the cassette case so as to be able to be opened and closed about a rotating shaft, and a front cover locking mechanism. In the magnetic tape cassette, the locking mechanism has a protrusion that is provided at at least one of both ends of the case and protrudes from an opening in a side wall of one of the upper and lower cases so as to be operated by a lock release means on the recorder side. A lock lever, an elastic member that constantly deflects the lock lever toward the end plate, a presser of the elastic member provided on one of the cases to press the rear end, and a retainer of the elastic member that can be engaged with the locking pawl of the lock lever. and a lock lever regulating and guiding means formed between the upper and lower cases to guide sliding of the lock lever in the locking direction and the releasing direction. , there is provided a locking mechanism for a magnetic tape cassette, wherein the lock lever further has an inner hole for accommodating the elastic member and a slot for pushing the elastic member.

In a preferred example, the sliding member of the lock lever is
It has a cylindrical part with an open rear end and a part of the rear wall cut out, the compression spring is housed in the inner hole of the cylindrical part, and the rear end extends from the case side to the rear of the lock lever. The cylindrical portion is restrained by a spring holder, and the spring holder is configured to relatively fit into the inner hole along the notch when the cylindrical portion is retreated by the release means.

According to the structure of the present invention, the lock lever is assembled into the cassette case by first assembling the compression spring and the lock lever, and then sliding the protrusion of the lock lever along the groove provided on the inner surface of the side wall of the case while sliding the lock lever to one side. For example, the protrusion is inserted into the recess of the upper case, the protrusion is inserted into the opening in the side wall, and the spring is held down by a spring holder. Next, when the lower cases are combined, the guide means and position regulating ribs of both cases stably hold and guide the lock lever. According to the present invention, the spring presser can be positioned close to the side wall, and the rear end of the lock lever can also be close to the side wall during assembly work of the lock lever, without interfering with internal parts or the tape running path. In other words, the front cover locking mechanism of the present invention requires minimal space and has little interference with other parts. Furthermore, according to the structure of the present invention, the compression spring is housed in the inner hole of the lock lever, compressed through the slot for holding the spring, and can be assembled into a predetermined location in the case as it is, so there is no need for the spring to fall off or other difficulties. This makes it extremely easy to incorporate the lock lever into the machine, improving work efficiency.

(Specific description of the invention) Hereinafter, embodiments of the invention will be described in detail in connection with a VHS-C type magnetic tape cassette, but the invention can be applied to any type of magnetic tape cassette with a front cover. It is clear that it can also be applied to

Regarding the overall structure, FIG. 1 is a perspective view of a magnetic tape cassette according to an embodiment of the present invention, and FIG. 2 is an exploded view of the same.
FIG. 3 is an enlarged perspective view showing the main part at the lower left corner of FIG. 1, and FIG. 4 is an enlarged perspective view showing the lock lever in dotted lines.

As shown in the figure, the magnetic tape cassette consists of a case 3 in which an upper case 1 and a lower case 2 are joined together at the outer periphery, and a pivot pin 7 at both ends of the case 3 (upper case 1 in this example) at the front part 4 of the case 3. , 7 and is constantly pushed in the closing direction by a spring 8. Note that 9 is a transparent window of the upper case 1. Inside the case 3 are lower flanges 12 and 13 that integrally have reel hubs 10 and 11, and a tape clamp 1.
Reels 18 and 19 having upper flanges 6 and 17 and upper flanges 14 and 15, respectively, are rotatably housed, and magnetic tape (not shown) is wound around them. The flanges 14 and 15 are held down by leaf springs 20 fixed to the upper case 1. Lower case 2
is provided with an axle 21 for the reel 18 and a circular opening 22 for the reel 19. There are other means for joining the upper and lower cases 1 and 2 together, but they are omitted because they are not related to the subject matter. A pin 23 for supporting a guide roller 24, a pin 26 for supporting a guide roller 25, and a pin 27 for supporting an auxiliary guide roller 28 are provided at the left corner of the front part 4 of the lower case 2, and a guide roller is provided at the right corner. 30 and a guide roller 32
A pin 31 is provided to support the. The magnetic tape runs from the reel 18 through the guide rollers 24, 26, the case front part 4, and the guide rollers 30, 32 to the reel 19. The auxiliary guide roller 28 serves to guide the tape laterally when the cassette is attached to a VHS recorder using an adapter.

As can be seen from the figure, the areas with some margin in the front part 4 of the case 3 of the cassette are the left and right corners, but the flanges 12, 13, 1 of the reel
4 and 15 are relatively large with respect to the case 3, and the lower flange 12 extends to the middle of the thickness of the case side wall 33, so there is little margin at the corner, and
Since the guide rollers 24, 26, and 28 are provided, the width becomes narrower. Figures 3 and 4 show the state of the left corner. Therefore, there is no room to install a conventional sliding lock mechanism or swing lock mechanism in this location, so a fundamental improvement is required. The locking mechanism 40 of the present invention solves this problem. Although the lock mechanism 40 is illustrated as being provided at the left end of the front part, it may also be provided at the right end.

Regarding the Lock Mechanism Next, the lock mechanism 40 of the present invention will be explained with reference to FIGS. 5 to 9 in addition to FIGS. 3 to 4. The lock mechanism 40 consists of a lock lever, a locking portion on the front lid side, lock lever regulating and guiding means on the upper and lower cases, and a compression spring.

Referring to FIGS. 3, 4, and 7, the left end of the front cover 5 has an end plate 34 (the right end is similar, but a description thereof will be omitted), and a pivot pin 7 is provided thereto to attach the upper case side wall 33. It is pivotally mounted at the front end and adapted to pivot between the closed position shown in FIG. 1 and the open position shown in FIG. A portion of the inner surface of the end plate 34 is recessed to provide a locking portion 43 (FIG. 7) for the locking pawl 42 of the lock lever 41.

The lock lever 41 includes a protrusion 45 that protrudes from an opening 44 in the side wall 33 of the upper case and is pressed by a lock release pin (not shown) on the recorder side, a positioning wall 46 of the upper case 1 that extends rearward from this protrusion, A cylindrical portion 52 (square in this example) that is guided by contacting the guide surfaces 49 and 50 of the position regulating rib 47 of the lower case 2 and a guide rib 53 of the upper case 1
The support plate 56 has a slot 54 that fits into the support plate 56 and a locking pawl 42 via an arm 55. The forward stroke of the support plate 56 is restricted by the inner surface of the side wall 33, and the backward stroke is restricted by the restriction rib 47. Furthermore, the lower surface 6 of the support plate 56
2 is guided by the upper surface 51 of the regulating rib.

An inner hole 57 is formed in the cylindrical portion 52 of the lock lever 41, and a compression coil spring 58 is accommodated therein. When the compression spring 58 is free, it protrudes from the open end of the bore 57 as shown in FIG. Inner hole 5
The upper surface of the rear portion of 7 has a notch 59 (FIG. 7), into which a spring retainer 6 extending downward from upper case 1 enters and presses the rear end of compression spring 58.
The cylindrical portion 52 further includes a vertical slot 61. This is when installing the lock lever 41.
This is because the compression spring 58 is held down by a thin jig, and this jig is further passed through the slot 61 to compress the spring, and in this state, the spring is pushed into a predetermined location in the upper case 1, thereby assembling the spring. This allows easy and quick assembly.

Assembling the Lock Lever As shown in FIG. 8, the lower side of the opening 44 provided in the side wall 33 of the upper case has a groove 63 on the inner surface of the side wall so as to be thinner than the other portions of the side wall. This groove connects the lock lever 41 to the upper case positioning wall 4.
6. When the lock lever is assembled into the guide and support structure formed by the guide rib 53 and the opening 44, it provides an escape for the protrusion 45 of the lock lever to slide thereon. Using this escape,
The lock lever guide/regulating structure is made smaller, and the position of the rear end of the lock lever when it is retracted is closer to the side wall 33, saving space.

To assemble the lock lever 41, as shown in FIG.
1 through the inner hole 5 of the lock lever.
7 and compress it. The compression spring is thus held stably within the bore 57. This is then pushed into the recess at the front of the spring holder 60. As shown in FIG. 8, the slot 61 is located on the open side of the upper case 1 (towards the left in the figure), so the lock lever can be positioned at a predetermined position while the jig is inserted into the slot 61. In this position the spring is extended and the protrusion 4
5 is exposed through the opening 44 of the side wall 33.

(Operation and Effect) As shown in Figs. 8 and 10, assemble the compression spring 58 into the lock lever, press the spring 58 through the slot 61 with a jig such as tweezers, and hold the spring 58 in the upper case as shown by the arrow. 60 into the void surrounded by the positioning wall 46 and the side wall 33. At this time, the support plate 56
The slot 54 on the upper end side fits into the guide rib 53. When pushed all the way, the protrusion 45 will open at the opening 44.
The rear end of the spring 58 is held down by a spring retainer 60 inserted into the open end of the inner hole of the cylindrical portion 52 of the lock lever (see FIGS. 6 and 7). In order to save space, it is preferable for the spring retainer 60 to protrude into the inner hole of the cylindrical portion 52 as shown in FIGS. Even if the lock lever 41 is configured to fit into the inner hole when retracting, the effect of saving space is significant.

Next, when the lower case 2 and the upper case 1 are combined, the surfaces 49, 50, 5 of the position regulating ribs 47, 48
1 is the surface of the cylindrical part 52 of the lock lever and the support plate 5
6, respectively, to provide reliable support and guidance of the lock lever.

The assembled state is shown in FIGS. 1, 3, 5, and 9, and the state in which the front cover 5 is closed and locked by the locking mechanism is shown in FIGS. 1, 3, and 6. , 7, and the state in which the front cover is released and opened is shown in FIG. 5.

Now, when the lock release pin on the recorder side acts on the protrusion 45 of the lock lever 41 and pushes it, the lock lever retreats to the chain line position in FIG. It comes off from section 43. The front cover is opened by means on the recorder side. Conversely, from the state shown in Fig. 5, the front cover 5 is
When the lock is pushed into the closed position, the lock automatically engages and locks.

When the lock lever retreats from the state shown in FIGS.
or remain largely within the bore. Therefore, the space occupied by the compression spring 58 and the spring presser 60 almost coincides with the space occupied by the lock lever itself.
Thus, the present invention has the great advantage of being able to function satisfactorily in a very small space.

According to the present invention, the compression spring is reliably held during the assembling operation of the lock lever, thereby significantly streamlining the assembling operation.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an example of a magnetic tape cassette equipped with the locking mechanism of the present invention, Fig. 2 is an exploded view of the same, and Fig. 3 is an enlarged partially broken view of the left front end of the cassette having the locking mechanism. A perspective view, FIG. 4 is a perspective view similar to FIG. 3 with the lock lever shown in dotted lines,
Figure 5 is a side view of the same side with the front lid open, and Figure 6 is the same side view of the front cover in the open state.
A sectional view taken along the line A-A in the figure, FIG. 7 is a plan sectional view of the main part,
FIG. 8 is a perspective view of the upper case and lock lever, FIG. 9 is a perspective view of the lock mechanism on the lower case side, and FIG. 10 is a sectional view showing the process of assembling the compression spring. DESCRIPTION OF SYMBOLS 1... Upper case, 2... Lower case, 3... Case, 5... Front cover, 7... Pivot pin, 40... Lock mechanism, 41... Lock lever, 42... Locking claw, 43... ... recess, 44 ... locking part, 45 ... protrusion, 46 ... positioning wall, 47 ... regulating rib,
48... Regulatory rib, 49... Horizontal surface, 50... Vertical surface, 51... Horizontal surface, 52... Cylindrical portion, 53...
... Guide rib, 54 ... Slot, 55 ... Arm, 56 ... Support plate, 57 ... Inner hole, 58 ... Compression spring, 59 ... Notch, 60 ... Spring holder, 6
2...Bottom surface.

Claims (1)

[Scope of utility model registration request] A magnetic tape cassette including a cassette case consisting of an upper case and a lower case, a front cover having end plates pivotally attached to both ends of the front part, and a front cover locking mechanism, wherein the locking mechanism is configured to lock the cassette case at both ends of the case. a lock lever having a protrusion protruding from an opening in a side wall of one of the upper and lower cases so as to be operated by a lock release means on the recorder side; and a lock lever that is always directed toward the end plate. a compression spring to be deflected; a spring retainer provided on the one case to press the rear end; and a lock provided on one end plate of the front cover so as to be able to engage with a locking pawl of the lock lever. Department and
The lock lever includes a lock lever regulating and guiding means formed between the upper and lower cases so as to guide the sliding movement of the lock lever in the locking direction and the releasing direction, and the lock lever further includes an inner hole that accommodates the compression spring, and a lock lever that accommodates the compression spring. 1. A locking mechanism for a magnetic tape cassette, characterized in that it has a slot for pushing into the magnetic tape cassette.