JP2000260156A - Magnetic tape cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the satisfied holding function of a leader pin by improving the working accuracy and mountability of a spring member attachably/ detachably holding the leader pin. SOLUTION: In the magnetic tape cartridge, a single reel wound with the magnetic tape 6 is rotatably housed in a cartridge case 4, and a lock member 9 is provided for attachably/detachably fixing and holding both end parts of the leader pin 5 which are fixed to a tip of the magnetic tape 6, to a case 3. This lock member 9 is furnished with a plate-like mounting part 9a and an elastic arm part 9b bent from the mounting part 9a so that a tip restraining part 9c is allowed to abut on the leader pin 5, then the inner angle made by the mounting part 9a and the elastic arm part 9b is formed to the acute angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge case in which a single reel on which a magnetic tape is wound is rotatably housed in a cartridge case, and a leader pin for pulling out the magnetic tape is fixed to the end of the magnetic tape. More particularly, the present invention relates to a lock member for detachably holding the leader pin and an attachment structure thereof.

[0002]

2. Description of the Related Art Conventionally, a magnetic tape cartridge used as a recording medium used in an external storage device such as a computer has a magnetic tape wound around a single reel.
A type in which this reel is rotatably housed in a cartridge case is known. Since this magnetic tape is used for data storage of a computer or the like and stores important information, it is configured so that troubles such as tape jamming do not occur and the magnetic tape is not pulled out carelessly. I have.

A leader member (leader pin in the present invention) is fixed to the leading end of the magnetic tape, and a drive device is constructed so that the leader member is pulled out on the computer side to take up or rewind. The leader member is detachably held in the cartridge case, and using a spring member for holding the leader member is advantageous in terms of structural simplification and the like.

[0004]

By providing a lock member having upper and lower holding portions abutting on the upper and lower ends of the leader pin, the assemblability to the upper and lower cases is improved. When the spring is formed by punching and bending by press working, there is a problem that the working accuracy is reduced depending on the form of the lock member, and the locking force of the leader pin varies.

More specifically, a lock member formed by pressing a leaf spring having a configuration as shown in FIGS. 12 and 13 has been considered. In FIG. 12, the leader pin 5 fixed to the leading end of the magnetic tape 6 is inserted into and removed from an opening 10 formed in the side of the lower case 3 (same for the upper case) of the cartridge case 4. On the upper and lower wall surfaces, a concave storage portion 20 into which the end of the leader pin 5 is inserted and locked is provided, and a tapered insertion guide portion 21 is provided from the storage portion 20 toward the opening 10.
A lock member 50 for detachably holding the leader pin 5 in the storage section 20 is vertically symmetric as shown in FIG. 13, has a substantially U-shaped plane, and has a plate-like mounting section 50a extending along the case side wall 3b. The lower case 3 is sandwiched between the side wall 3b and a mounting boss 51 standing upright on the bottom surface of the lower case 3. Elastic arms 50b extending toward the opening 10 are continuously provided at upper and lower ends curved forward from the rear end of the mounting portion 50a, and a locking portion 50c is provided at a tip of the elastic arm 50b, respectively. The locking portions 50c contact both ends of the leader pin 5. The locking portion 50c is provided in a chevron shape protruding toward the leader pin 5, and is bent and deformed by contacting the leader pin 5 inserted and moved from the opening 10 on the slope on the distal end side, and the leader pin 5 is stored on the slope on the inner side. It is designed to be pressed and held inside.

Since the above-described lock member 50 is deeply U-shaped bent by pressing a leaf spring, the processing accuracy of the angle α (see FIG. 13) formed between the mounting portion 50a and the elastic arm portion 50b cannot be improved. However, the amount of deformation when the leader pin 5 is pressed and held differs, and the leader pin locking force tends to vary. Also, in order to press into a deep U-shape as described above, multiple press workings are required, and the number of steps is increased.
The length of the elastic arm portion 50b is increased and the development area is also large, so that a large amount of waste material is produced when the leaf spring material is punched and formed, which is disadvantageous in cost. Further, since the lock members 50 are curved in a U-shape, when a large number of the lock members 50 are accumulated, they are mutually overlapped and engaged with each other, and it is difficult to separate the lock members 50 into individual pieces, which may make continuous supply by the parts feeder difficult. There is.

On the other hand, in the mounting structure of the lock member 50 to the cartridge case 4, the plate-like mounting portion 50a of the lock member 50 is arranged along the case side wall 3b.
And a mounting boss 5 formed with a gap corresponding to the spring plate thickness
When the lock member 50 is made thinner in order to obtain an appropriate leader pin locking force,
The thickness of the mold portion for molding the gap between the mounting boss 51 and the side wall 3b becomes extremely thin, and there is a possibility that the mold portion may be damaged by the resin injection pressure during molding, and it is difficult to process the mold.
In particular, when the mounting boss 51 is formed to be high or long along the side wall 3b, the above phenomenon becomes remarkable.

Further, when assembling the plate-shaped lock member 50 to the cartridge case 4, depending on the fixing structure, the lock member 50 is set on the lower case 3, and when the upper case is overlaid and closed, the lock member 50 is closed. Member 50
May not be able to engage with the mounting boss 51 of the upper case, and may contact the end surface of the mounting boss 51 to prevent the upper case from being closed. In particular, around the leader pin 5, a drive side take-out mechanism needs a space for entering through the opening 10 and holding the leader pin 5, and the mounting boss 51 has a height so as not to interfere with the take-out mechanism. And the strength of the molding die cannot be increased from the viewpoint of the strength of the molding die, and there is a possibility that the above-mentioned problem due to falling may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has improved a processing accuracy and a mounting property of a spring member for detachably holding a leader pin, thereby obtaining a good leader pin holding function. Is to be provided.

[0010]

According to the magnetic tape cartridge of the present invention, which solves the above-mentioned problems, a single reel on which a magnetic tape is wound can be rotated by a lower case and an upper case superposed on the upper part of the lower case. A leader pin for pulling out the magnetic tape is fixed to the end of the magnetic tape, and a lock member by a leaf spring for fixing both ends of the leader pin to the case detachably is provided. A lock member is provided at the upper and lower ends of a plate-like mounting portion held by the lower case and the upper case, and an edge of the mounting portion on the leader pin side. The locking portion includes an elastic arm portion capable of contacting the leader pin, and an inner angle formed by the mounting portion and the elastic arm portion is obtuse.

[0011] It is preferable that an inner angle formed by the mounting portion of the lock member and the elastic arm portion is 135 ° or more.

Further, another magnetic tape cartridge of the present invention has a lock member formed by a leaf spring for detachably fixing both ends of the leader pin to the case, and the lock member is held by the lower case and the upper case. Plate-shaped mounting portion to be, and at the upper and lower ends of the edge of the mounting portion on the leader pin side,
The cartridge case is provided with a spring mounting portion for holding the lock member, the elastic case being bent from the mounting portion and extending in the direction of the leader pin, the distal end locking portion being provided with an elastic arm portion capable of contacting both ends of the leader pin. The spring mounting portion holds the lock member at a position inwardly away from the side walls of the lower case and the upper case. It is preferable from the viewpoint of mold strength that the spring mounting portion is formed at a distance of 0.4 mm or more from the side walls of the upper and lower cases.

In this case, the lock member has, at the upper and lower ends of the mounting portion, engaging recesses which are fitted and held by projections provided on the spring mounting portion, and are provided in the front-rear direction of the mounting portion. Preferably, positioning is also performed.

It is preferable that the spring mounting portion of the cartridge case is provided with a slope for guiding the lock member toward the projection. Further, in the lock member,
It is preferable to provide a guide portion at the insertion corner of the engagement recess to facilitate engagement with the spring mounting portion.

On the other hand, the spring mounting portion of the cartridge case is provided with a fall restricting portion for holding the end of the lock member mounting portion opposite to the elastic arm portion in an upright state to prevent the lock member from falling. Is preferred.

When assembling the lock member to the cartridge case as described above, screws for fastening the upper and lower cases are tightened through screw holes opened in the upper surface of the upper case, and the lock member is set in the lower case. After the upper case is overlaid, the cartridge case may be assembled without being turned upside down to improve the workability.

[0017]

According to the magnetic tape cartridge of the present invention as described above, the plate-shaped mounting portion bends from the upper and lower ends on the leader pin side and extends in the direction of the leader pin so that the leading end locking portion can contact the leader pin. By providing an obtuse angle between the mounting portion of the lock member formed by the leaf spring and the elastic arm provided with an elastic arm, the pressing accuracy of the deep curve is not required, thereby improving the processing accuracy and pressing and holding the leader pin. The amount of deformation at the time is constant and the locking force of the leader pin can be obtained stably, and the pressing process is easy and the process can be simplified. In addition, the length of the elastic arm is small, the development area is small and the cost is advantageous. Becomes Furthermore, even if a large number of lock members are accumulated, they are hardly engaged with each other, and continuous supply by the parts feeder is possible.

According to another magnetic tape cartridge of the present invention, a lock by a plate spring having a plate-shaped mounting portion and elastic arms bent at the upper and lower ends of the mounting portion in the direction of the leader pin is provided. By holding the lock member at a position inwardly away from the side walls of the lower case and the upper case, the spring mounting portion for holding the member in the cartridge case allows the cartridge case to be thinned even when the thickness of the lock member is reduced. The portion of the mold that forms the wall surface is not thin, so that the mold can be easily processed and breakage can be prevented.

If upper and lower ends of the mounting portion of the lock member are provided with engagement recesses to be fitted to the projections of the spring mounting portion, the positioning of the lock member in the front-rear direction is performed at the same time, and the positional accuracy with respect to the leader pin is increased. .

Further, if the spring mounting portion of the cartridge case is provided with a fall restricting portion for holding the end of the lock member in an upright state, for example, the lock member is set on the lower case, and the upper case is overlaid and closed. In this case, the locking member can be prevented from falling down while securing a space for the drive-side take-out mechanism, and good assemblability can be secured.

At this time, if a screw hole is opened in the upper surface of the upper case so as to assemble without turning the cartridge case upside down, the assembling property is further improved.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is an exploded perspective view of a magnetic tape cartridge according to one embodiment, FIG. 2 is a front view near an opening in a state where a slide door is opened, and FIG. 3 is a sectional view taken along line AA of FIG. FIG. 4 is a perspective view of the lock member, and FIGS. 5 and 6 are cross-sectional views of the spring mounting portion along the line BB and CC in FIG.

The magnetic tape cartridge 1 includes an upper case 2
A single reel 7 on which a magnetic tape 6 with a leader pin 5 fixed to the end is wound rotatably accommodated in a cartridge case 4 in which the lower case 3 is fastened by screws or the like. An opening 10 for drawing out the magnetic tape 6 is formed in one side wall of the upper and lower cases 2 and 3, and the opening 10 is opened and closed by a slide door 11 urged in a closing direction by elastic means (not shown). A groove-shaped door rail 12 (see FIG. 3) on which the slide door 11 slides is formed near the opening 10.

When the magnetic tape cartridge 1 is not in use, the leader tape 5 at the tip is engaged with the concave storage portion 20 formed near the opening 10 in a state where the magnetic tape 6 is completely wound around the reel 7. Is stopped. This storage unit 20
An insertion guide portion 21 (guide surface) formed in an inviting structure toward the opening portion 10 is continuously provided, and
Toward the end of the leader pin 5.

The leader pin 5 is held and pulled in by a drive device of a recording / reproducing apparatus using the magnetic tape cartridge 1 so as to introduce the magnetic tape 6 into a tape running path in the apparatus. The lock member 9 is provided by a leaf spring which detachably holds the storage unit 20 from the storage unit 20.

As shown in FIGS. 2 and 3, the leader pin 5 has, at the center thereof, an axial tape crank portion 5a which is wound around the leading end of the magnetic tape 6 and is clamped by fitting a clamp member 5e having a C-shaped cross section. , This tape clamp portion 5a
Plate-shaped upper and lower flange portions 5b, 5b are continuously provided on both upper and lower sides of the device, and thin engaging portions 5c, 5c which are engaged and held from the recording / reproducing apparatus side above and below the upper and lower flange portions 5b respectively extend in the axial direction. At both ends, fixing portions 5d, 5d for fixing the case are formed. The leader pin 5 is formed, for example, by cutting a metal bar (such as stainless steel), and its tape clamp portion 5 a has a length equal to the width of the magnetic tape 6.

The clamp member 5e is a resin molded product, has an axial length corresponding to the length of the tape clamp portion 5a of the leader pin 5, and has a slit extending in the axial direction over the entire length thereof. It is formed in a C-shaped cross section, and is provided so as to be elastically fitted to the outer periphery of the tape clamp portion 5a.

In FIG. 1, the upper and lower cases 2 and 3 are formed in a substantially rectangular shape, and side walls 2b and 3b are provided around an upper wall 2a and a bottom wall 3a. Arc-shaped inner wall 3c (the upper case 2 is not shown)
Is provided. The lower case 3 includes the side wall 3 b and the inner wall 3.
c and four bosses 3d (opening 10
The nearby boss portion is hidden by the slide door 11) and is brought into contact with a boss portion (not shown) of the upper case 2, and the screws are tightened from the bottom surface and fastened in an overlapping state. The screw may be tightened to the boss 3d from the upper surface as described later.

In the center of the lower case 3, a center hole 3e for rotating the reel 7 by a drive shaft of a drive device is opened.
At the rear end, a write protector member 1 for preventing writing
3 is slidably disposed. At the center of the reel 7, a rotation restricting mechanism 15 for restricting the rotation of the reel 7 when not in use is provided.

In addition, although not shown, a reel plate for attracting and holding the magnet type rotary drive means is attached to the bottom of the reel 7 at the center thereof, and the outer peripheral portion meshes with the drive gear of the rotary drive means. Reel gears are engraved. In a state where the reel gear and the drive gear are engaged with each other, the rotation restricting mechanism 15 is released and the reel 7 is rotatable.

Here, the leader pin 5 is connected to the storage section 20.
The lock member 9 which detachably holds the lock member 9 and its mounting structure will be described.

The lock member 9 is vertically integrated, and a substantially rectangular plate-like mounting portion 9a is provided near the case side walls 2b, 3b when the upper case 2 and the lower case 3 are overlapped. It is engaged with and held by the mounting portion 30 (the upper case 2 is not shown, but has the same shape as the lower case 3). At the upper and lower ends of the edge of the mounting portion 9a on the leader pin 5 side, the mounting portion 9a is positioned in the direction of the leader pin 5.
An elastic arm portion 9b that is bent and extends from the elastic arm portion 9b is connected to the distal end locking portion 9c of the elastic arm portion 9b.
Abuts the outer periphery of The front end locking portion 9c is
It is provided in the shape of a mountain protruding to the side, and the opening 1
The elastic arm 9 contacts the leader pin 5 which is inserted and moved from 0.
b is bent and deformed, and the leader pin 5 is pressed and held in the storage section 20 on the inner slope. An engagement recess 9d is provided at the upper and lower ends of the mounting portion 9a.

The inner angle β (see FIG. 4) formed by the mounting portion 9a and the bent elastic arm portion 9b is formed at an obtuse angle, preferably 135 ° or more. The locking member 9 has a plate thickness of 0.2 in order to obtain an appropriate leader pin locking force, depending on the length of the elastic arm portion 9b and the like.
mm to 0.3 mm. The thickness of the lock member 50 shown in FIG. 13 is about 0.4 mm. Also,
The upper and lower elastic arms 9b, 9b may be provided so as to be vertically connected at a root portion.

The spring mounting portions 30 of the upper and lower cases 2 and 3 for holding the lock member 9 as described above move the lock member 9 to a position distant from the side walls 2b and 3b of the upper and lower cases 2 and 3, preferably of a mold strength. It is provided so as to be held at least 0.4 mm away from the point.

The spring mounting portion 30 is formed integrally with the side wall 3b of the lower case 3 and is formed to project from the side wall 3b in a flat plate shape. And a second support portion 32. The first support part 3
1 is set to the holding position dimension, a gap between the first support portion 31 and the second support portion 32 is formed to be equal to or greater than the thickness of the mounting portion 9a of the lock member 9, and is mounted in this gap. The part 9a is inserted.

The width of the second support portion 32 is
1, and the height is formed higher. Further, the upper surfaces of the first support portion 31 and the second support portion 32
Slopes 31a, 32 that become lower toward the gap between them
a (see FIG. 5) to guide the end of the lock member 9 into the gap.

The first support portion 31 and the second support portion 3
A protrusion 33 (see FIG. 6) projecting from the bottom wall 3a is formed between the second support portion 32 and the second support portion 32. A gap into which the member 9 is inserted is formed, and is formed so as to correspond to the width of the engaging recess 9d formed at the upper and lower ends of the mounting portion 9a of the lock member 9, and is fitted with the engaging recess 9d. It is possible. Further, both sides of the upper end of the projection 33 are inclined surfaces 3.
3a, and furthermore, an engagement recess 9d of the lock member 9
Both side corners of are also obliquely removed to form a guide portion 9e,
Guide the engagement of both.

With the above mounting structure, the lower case 3
As shown in FIGS. 5 and 6, between the first support portion 31 and the second support portion 32 of the spring mounting portion 30, the mounting recess 9d of the lower end of the mounting portion 9a of the lock member 9 is It is inserted and mounted while being guided by the slopes 31a, 32a, 33a and the guide portion 9e so as to be engaged with the projection 33. Then, after assembling other components such as the reel 7 into the lower case 3, the upper case 2 is overlapped on the lower case 3, and the mounting portion 9 a of the lock member 9 is attached to the spring mounting portion 30 of the upper case 2. The upper ends of the upper and lower cases 2 and 3 are engaged, and screws are tightened in a state where the upper and lower cases 2 and 3 are closed.

At this time, the lock member 9 is positioned in the vertical direction by sandwiching the spring mounting portions 30 of the upper and lower cases 2 and 3, and the locking member 9 is moved in the front-rear direction by the engagement between the projection 33 and the engagement recess 9d. Positioning is also performed, and a contact position between the distal end locking portion 9e and the leader pin 5 is secured.

The first support portion 3 of the spring mounting portion 30
1 may be provided in a discontinuous divided structure as shown in FIG. 7, which is advantageous in terms of mold strength.

Next, FIGS. 8 and 9 show another embodiment, in which the lock member 9 is formed in the same manner as the previous example, and the form of the spring mounting portion 30 is different.

That is, the spring mounting portion 30 of the lower case 3
The first support portion 31, the second support portion 32, and the protrusion 33 are formed in the same manner as described above, and the elastic portion of the mounting portion 9 a of the lock member 9 is provided at the inner end of the first support portion 31. A fall restricting portion 34 for holding the end opposite to the arm 9b in an upright state is provided. A first support portion 31, a second support portion 32, and a protrusion 33 similar to those described above are formed on a spring mounting portion 30 of the upper case 2, and a fall restricting portion 34 is not formed.

The fall restricting portion 34 extends vertically in a rib-like shape and is formed higher than the first support portion 31 and the second support portion 32. The locking member 9 extends vertically so as to form a gap corresponding to the thickness of the lock member 9 and holds the lock member 9 in a vertical state. Note that an inclined guide portion 34a is formed at the upper end of the fall restricting portion 34.

In the present embodiment, when the lock member 9 is set on the spring mounting portion 30 of the lower case 3, the fall of the lock member 9, particularly the fall toward the inside of the case, is regulated by the fall regulation portion 34, and the upper case 3 When the two are overlapped, the lock member 9 is securely engaged with the spring mounting portion 30 of the upper case 2 to improve workability.

FIGS. 10 and 11 show another embodiment of the above embodiment, in which the first support portion 31 of the spring mounting portion 30 in FIGS. 8 and 9 is provided in a discontinuous divided structure. In particular, the first support portion 31 of the lower case 3 is
4 is provided at a position distant therefrom. In such a structure,
This is advantageous in securing the strength of the mold during molding.

In the above description, the lower case 3 is placed upward, the lower end of the lock member 9 is set on the lower case 3, and then the upper case 2 is overlaid. Alternatively, the lock member 9 may be set by placing the upper case 2 upward, and the lower case 3 may be overlapped. In this case, it is necessary to provide the fall restricting portion 34 on the upper case 2.

In the case where a screw hole is formed in the lower surface of the lower case 3, when the lower case 3 is placed upward and the lock member 9 is set as described above, the upper case 2 is overlapped. After that, the screws are tightened by turning the cartridge case 4 upside down, but if the screw holes are provided on the upper surface of the upper case 2, the screws can be tightened without turning the cartridge case 4 upside down. Since the working process can be simplified, it is preferable to dispose the screw holes corresponding to the assembling process.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a magnetic tape cartridge according to one embodiment of the present invention.

FIG. 2 is a front view of the vicinity of an opening with a sliding door opened.

FIG. 3 is a plan view of a cross section taken along line AA of FIG. 2;

FIG. 4 is a perspective view of a lock member.

FIG. 5 is a cross-sectional view of the spring mounting portion along the line BB in FIG. 3;

FIG. 6 is a cross-sectional view of the spring mounting portion along the line CC in FIG. 3;

FIG. 7 is a sectional view of a spring mounting portion showing another mode of the embodiment of FIG. 6;

FIG. 8 is a plan view showing the vicinity of an opening in a state where an upper case of a magnetic tape cartridge according to another embodiment is removed.

FIG. 9 is a perspective view of a main part of the lock member shown in FIG. 8 in an attached state.

10 is a plan view of the magnetic tape cartridge according to another embodiment of the embodiment in FIG. 8 in the vicinity of an opening with an upper case removed.

FIG. 11 is a perspective view of a main part in a state where the lock member of FIG. 10 is mounted.

FIG. 12 is a plan view showing the vicinity of an opening in a state where an upper case of a magnetic tape cartridge according to a conventional embodiment is removed.

FIG. 13 is a perspective view of the lock member of FIG. 12;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic tape cartridge 2 Upper case 3 Lower case 2b, 3b Side wall 4 Cartridge case 5 Leader pin 6 Magnetic tape 7 Reel 9 Lock member 9a Attachment part 9b Elastic arm part 9c Tip locking part 9d Engaging concave part 9e Guide part β Inner angle 10 Opening Part 20 Storage part 30 Spring mounting part 31 First support part 32 Second support part 33 Projection 34 Fall-down regulating part 31a, 32a, 33a Slope 34a Guide part

Claims (5)

[Claims] A cartridge case for rotatably accommodating a single reel on which a magnetic tape is wound by a lower case and an upper case superimposed on an upper portion of the lower case;
A magnetic tape cartridge having a leader pin for pulling out the magnetic tape fixed to a leading end of the magnetic tape, comprising: a locking member formed of a leaf spring that removably fixes both ends of the leader pin to a case; Is
A plate-shaped mounting portion held by the lower case and the upper case, and upper and lower ends of an edge of the mounting portion on the leader pin side, the bending portion extends from the mounting portion in the direction of the leader pin, and a distal end locking portion is provided. A magnetic tape cartridge comprising: an elastic arm portion capable of contacting a leader pin; and wherein an inner angle formed by the attachment portion and the elastic arm portion is provided at an obtuse angle. 2. The magnetic tape cartridge according to claim 1, wherein an inner angle between the mounting portion and the elastic arm portion of the lock member is 135 ° or more. 3. A cartridge case for rotatably accommodating a single reel on which a magnetic tape is wound by a lower case and an upper case superimposed on an upper portion of the lower case,
A magnetic tape cartridge having a leader pin for pulling out the magnetic tape fixed to a leading end of the magnetic tape, comprising: a locking member formed of a leaf spring that removably fixes both ends of the leader pin to a case; Is
A plate-shaped mounting portion held by the lower case and the upper case, and upper and lower ends of an edge of the mounting portion on the leader pin side, the bending portion extends from the mounting portion in the direction of the leader pin, and a distal end locking portion is provided. An elastic arm portion capable of abutting a leader pin, wherein the cartridge case is provided with a spring mounting portion for holding the lock member, and the spring mounting portion places the lock member at least 0.4 mm from the side walls of the lower case and the upper case. A magnetic tape cartridge which is held at a remote position. 4. The locking member according to claim 1, wherein upper and lower ends of a mounting portion are provided with engaging recesses which are positioned and held by being fitted to projections provided on the spring mounting portion. 4. The magnetic tape cartridge according to 3. 5. The spring mounting portion of the cartridge case is provided with a fall restricting portion for holding an end of the mounting portion of the lock member opposite to the elastic arm portion in an upright state. 4. The magnetic tape cartridge according to 3.