JP3749988B2 - Single reel type magnetic tape cartridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a single reel type magnetic tape cartridge in which a reel lock mechanism is provided inside a reel boss.
[0002]
[Prior art]
A single reel type magnetic tape cartridge (hereinafter simply referred to as a tape cartridge) is known, for example, in Japanese Patent Application Laid-Open No. 11-7747. There, a reel drive mechanism that also serves as a reel presser is provided inside the reel boss, and a reel lock mechanism is provided facing the flange peripheral surface of the reel in order to prevent reel play and tape sagging when not in use. .
[0003]
Since the above tape cartridge is provided with a reel lock mechanism separately, the number of parts increases accordingly. Therefore, the present inventors have previously proposed a tape cartridge in which a reel lock mechanism is incorporated inside the reel boss as shown in FIG. 8 (Japanese Patent Application No. 10-56226). In this case, the reel presser 42 arranged inside the boss 41 of the reel 40 is pressed down and biased by a spring 43 to prevent the reel 40 from rotating. The reel presser 42 is engaged and guided by a cross-shaped guide 44 provided in the upper case so as to be freely slidable up and down. The lock teeth 45 provided on the bottom surface of the reel presser 42 are engaged with the lock teeth 46 on the inner bottom of the boss 41. This prevents the reel 40 from rotating and floating.
[0004]
Between the reel retainer 42 and the inner bottom wall of the boss 41, there is provided a lock release tool 47 press-molded in a trifurcated shape. When the lock release tool 47 is pushed up against the biasing force of the spring 43, the engagement of the lock teeth 45 and 46 is released, so that the reel 40 can be driven to rotate. When the reel is driven, the unlocking tool 47 rotates along with the reel 40. In order to reduce the frictional resistance at this time as much as possible, a protrusion 48 that swells in a mountain shape is provided at the center of the plate surface of the unlocking tool 47. A concave portion 49 having a partially spherical shape is provided at the center of the bottom surface of the presser 42. The spherical radius of the recess 49 is larger than that of the protrusion 48.
[0005]
[Problems to be solved by the invention]
As described above, in the tape cartridge having the reel presser 42 pressed and biased by the spring 43, the reel presser 42 that remains stationary when the reel is driven and the unlocking tool 47 that rotates along with the reel 40 are interposed. Large sliding friction acts. Furthermore, while the lock release tool 47 is formed of a stainless steel plate material, the reel presser 42 is made of a plastic molded product, and there is a large difference in the hardness of both. Therefore, although the protrusion 48 and the concave portion 49 are joined in a point contact manner, the concave portion 49 is gradually scraped with the use of the tape cartridge. The scraped plastic powder adheres to the signal recording surface of the tape and causes noise, and also causes the recording signal to be lost. As wear of the recess 49 progresses, the contact area between the protrusion 48 and the recess 49 increases, and the drive torque of the reel 40 may increase abnormally.
[0006]
The object of the present invention is to improve the connection structure between the reel presser and the unlocking tool that must be rotated relative to each other, thereby changing the friction form between the two from sliding friction to rolling friction or semi-rolling friction. Therefore, it is intended to prevent the wear and plastic powder from being generated at the joint portion due to tape use, and improve the reliability of the tape cartridge during long-term use.
[0007]
[Means for Solving the Problems]
In the tape cartridge of the present invention, as shown in FIG. 1, a reel 2 around which a magnetic tape 3 is wound is disposed inside a box-shaped case body 1, and the inside of a boss 12 provided at the center of the reel 2. A reel lock mechanism is provided between the bottom and the upper wall of the case main body 1 to prevent idle rotation of the reel 2 when not in use. As shown in FIGS. 1 and 4, the reel lock mechanism is slidable up and down by a guide projection 15 projecting from the inner surface of the upper wall of the case main body 1, but the reel presser 16 is engaged and guided so that relative rotation is impossible. And a spring 17 that presses and urges the reel presser 16 and a facing surface between the lower surface of the reel presser 16 and the upper surface of the bottom wall of the boss 12, and abuts and engages with each other to prevent the reel 2 from rotating. And lock teeth 19 and 20. Between the reel presser 16 and the bottom wall of the boss 12, there is disposed an unlocking tool 18 that is pushed up by the drive shaft D to unlock the reel presser 16 against the biasing force of the spring 17. A ball 26 is rotatably held on the lower surface of the reel presser 16. Therefore, the reel presser 16 and the lock release tool 18 are joined via the ball 26 so as to be relatively rotatable.
[0008]
Specifically, a socket portion 25 having a cross-sectional arc is provided on the base wall 21 of the reel retainer 16 facing the bottom wall of the boss 12, and the ball 26 is press-fitted and attached to the socket portion 25 in a rotatable state. The lock release tool 18 is formed of a metal plate press-formed product, and the ball 26 is a steel ball. As shown in FIG. 7, a rotation receiving surface 25 a for receiving the peripheral surface of the ball 26 is formed on the inner surface of the socket portion 25 in a circular shape.
[0009]
[Operation and effect of the invention]
Since the reel presser 16 and the lock release tool 18 are joined via a ball 26 held rotatably, the friction form between the reel presser 16 and the lock release tool 18 when the reel 2 is driven to rotate is rolling friction. Or, it can be a half-rolling friction, and it is possible to prevent the wear of the joint part and the generation of plastic powder due to the friction. Therefore, compared to the conventional type in which the friction form between the reel presser and the lock releaser is sliding friction, the reliability during long-term use is improved, and the driving torque when the reel 2 is rotationally driven can be reduced. It is. Incidentally, the half-rolling friction means a friction form when the ball 26 rotates intermittently and irregularly even if the ball 26 does not always rotate.
[0010]
When the socket portion 25 is provided on the base wall 21 of the reel presser 16 and the ball 26 is press-fitted and mounted in a rotatable state, the ball 26 can be integrated with the reel presser 16, so that the reel lock mechanism is assembled. It can be simplified. It is possible to prevent the ball 26 from being separated from the reel presser 16 even when the reel presser 16 receives a drop impact and moves in a direction to float against the spring 17.
[0011]
When a steel ball is used as the ball 26 and the unlocking tool 18 is formed of a press-molded product made of a metal plate such as a stainless steel plate, the ball 26 and the unlocking tool 18 are joined without being locally deformed. The friction form between 18 and 26 can be brought as close as possible to an ideal point contact state, and, for example, compared with the case of using a plastic ball 26, the frictional force can be reduced and the durability of the joint can be improved.
[0012]
If the rotation receiving surface 25a is formed in a circular shape on the inner surface of the socket portion 25, the ball 26 is received in a line contact manner by the rotation receiving surface 25a, and the frictional resistance between the socket portion 25 and the ball 26 is reduced. Accordingly, the driving torque of the reel 2 can be reduced. Since the ball circumferential surface is received by the ring-shaped rotation receiving surface 25a and the ball 26 can always be rotated at a fixed position, the ball 26 is prevented from rotating while swinging precessively inside the socket portion 25. Thus, the rotation fluctuation of the reel 2 can be suppressed by that amount.
[0013]
【Example】
1 to 7 show an embodiment of a single reel type magnetic tape cartridge according to the present invention. In FIG. 2, the magnetic tape cartridge contains a reel 2 inside a rectangular box-shaped case body 1 formed by joining upper and lower cases 1a and 1b in a lid-like manner. Tape). A loading pin 4 for pulling out the tape 3 is connected to the feeding end of the tape 3. The loading pin 4 is positioned and accommodated inside a tape outlet 5 opened at the front right corner of the case body 1, and the upper and lower ends thereof are holders 6 and 6 provided on the inner surfaces of the upper case 1a and the lower case 1b. Engagement is held. The tape outlet 5 can be opened and closed with a slidable lid 7 which is closed and urged by a spring (not shown).
[0014]
In FIG. 3, the reel 2 includes an upper flange 10, a lower flange 11, and a boss 12 that is formed integrally with the lower flange 11 and opens upward. Between the inner bottom of the boss 12 and the upper wall of the upper case 1a. In addition, a reel lock mechanism for preventing the idle rotation of the reel 2 when not in use is provided. The upper flange 10 is welded and fixed to the upper end of the boss 12 so as not to be separated. A circular suction plate 13 is welded and fixed to the center of the bottom surface of the bottom wall of the boss 12, and drive teeth 14 are provided in a circular manner so as to surround the suction plate 13 (see FIG. 6). The adsorption plate 13 is formed of a metal plate capable of magnetic adsorption such as an iron plate or a steel plate. The drive teeth 14 are formed of a group of sawtooth-shaped gear teeth extending in the radial direction, and are engaged with the drive teeth provided on the shaft end face of the drive shaft D of the tape drive as shown in FIG. Inherits the rotational force of axis D. The drive teeth 14 are exposed to the outer surface of the case through drive holes 8 provided in the bottom wall of the lower case 1b.
[0015]
In FIG. 3, the reel lock mechanism includes a reel presser 16 which is slidably engaged with the guide protrusion 15 provided on the inner surface of the upper case 1a but cannot be relatively rotated, a reel presser 16 and the upper case 1a. And a compression coil spring 17 disposed between them, and lock teeth 19 and 20 provided on the upper surface of the bottom wall of the boss 12 and the lower surface of the reel presser 16. As shown in FIG. 4, the guide protrusion 15 is formed in a cross-shaped cross section with two guide walls that intersect perpendicularly. An unlocking tool 18 is disposed between the reel presser 16 and the bottom wall upper surface of the boss 12 in order to unlock the reel presser 16.
[0016]
In FIG. 4, the reel presser 16 is formed of a round dish-shaped plastic molded product that is open upward and has an annular regulating wall 22 for tilting regulation protruding from the periphery of a circular base wall 21. Four L-shaped ribs 23 project from the center of the upper surface of the base wall 21, and these ribs 23 define a cross-shaped slide groove 24. By fitting the guide protrusion 15 in the slide groove 24, the reel presser 16 is guided only in a vertical slide manner. As shown in FIG. 3, a socket portion 25 is provided at the center of the bottom surface of the base wall 21, and a group of lock teeth 20 project around the socket portion 25 in a circular shape. The lock tooth 20 is formed of a tooth body having a mountain-shaped cross section extending in the radial direction, and its outer edge diameter dimension is set to be sufficiently smaller than the outer diameter dimension of the regulating wall 22. The spring 17 is mounted so as to be fitted on the guide protrusion 15, and the lower end thereof is received by the upper surface of the base wall 21.
[0017]
In FIG. 7, the socket portion 25 is formed of a spherical recess having a cross-section with an arc-like shape, and a ball 26 is rotatably fitted in the inside thereof. On the inner surface of the socket portion 25, a rotation receiving surface 25a for receiving the upper half side peripheral surface of the ball 26 is formed in a circular shape. Further, a rib 25b that bulges the ball 26 and keeps it from detaching is formed near the lower end of the inner surface. The rotation receiving surface 25a is formed as an upwardly tapered surface, and therefore circumscribes the ball 26 in a line contact manner. The lower peripheral surface of the ball 26 attached to the socket portion 25 protrudes downward from the lower surface of the base wall 21. In order to avoid contact interference with the socket portion 25, the intersecting portion of the guide protrusion 15 is recessed in a circular shape.
[0018]
As shown in FIG. 4, the unlocking tool 18 is made of a press-molded product made of a steel plate such as a stainless steel plate, and three arms 28 are radially extended from the periphery of the circular main surface wall 27 at regular intervals. A leg piece 29 that is bent downward is integrally formed at the tip of the arm 28. In the center of the main surface wall 27, a horizontal joint 30 that receives the previous ball 26 is formed to bulge upward. The lock release tool 18 in the normal state receives the urging force of the spring 17, and the main surface wall 27 is received and supported by the base wall 21. In this receiving state, in order to prevent each arm 28 from contacting and interfering with the lock teeth 19 on the boss 12 side, as shown in FIG. 5, the annular row of the lock teeth 19 is divided at three locations in the circumferential direction. Each arm 28 is positioned in the divided portion 19a. Further, three openings 31 are provided in the bottom wall of the boss 12 in a vertically penetrating manner so that the leg pieces 29 provided at the tips of the arms 28 protrude from the lower surface of the reel 2.
[0019]
The drive teeth 14 provided on the bottom surface of the bottom wall of the boss 12 are engaged with the drive shaft D of the tape drive and inherit the rotational force. In order to push up the unlocking tool 18 using this engagement operation, the opening 31 is formed in the formation region of the drive teeth 14 and the leg piece 29 is projected to the reel lower surface side. By providing the opening 31, the strength of the drive teeth 14 intersecting with the opening 31 is reduced, and the drive teeth 14 are easily lost. In order to avoid such a decrease in strength of the drive teeth 14, as shown in FIG. 6, three missing tooth portions 32 are provided corresponding to the positions where the openings 31 are formed. The missing tooth portion 32 is formed by omitting several drive teeth 14 in a state of reaching the root surface. When the reel is locked, the leg piece 29 protrudes into the missing tooth portion 32, but its lower end surface is located on the tooth tip plane of the drive tooth 14.
[0020]
In the reel lock mechanism having such a configuration, the reel presser 16 is held non-rotatably by the guide projection 15 and is always pushed down by the spring 17. Further, lock teeth 19 and 20 provided on the reel presser 16 and the bottom wall of the boss 12 are engaged with each other. Therefore, the reel 2 in the non-use state can be locked and held so as not to rotate.
[0021]
In use, the lid 7 is opened on the tape drive side and the loading pin 4 is captured by the loading mechanism. At the same time, the drive shaft D is pressed against the lower surface of the bottom wall of the boss 12 as shown in FIG. 1, and the drive teeth are engaged with the drive teeth 14 on the reel 2 side. By this joining operation, the lower surface of the reel 2 is lifted from the bottom wall of the lower case 1b. Further, the leg piece 29 is pushed up by the drive teeth of the drive shaft D and pushed upward in the opening 31. As a result, the lock release tool 18 pushes up the reel presser 16 against the urging force of the spring 17 via the ball 26 and releases the lock teeth 19 and 20 engaged so far to release the reel lock state. To do. As a result, the reel 2 can be rotated and the tape 3 can be fed out or driven. Thereafter, when the drive shaft D is separated from the reel 2, the reel 2 can be locked again.
[0022]
In order to prevent the reel presser 16 from tilting and engaging the lock teeth 20 with the lock teeth 19 on the boss 12 side in the unlocked state, the gap between the upper end periphery of the restriction wall 22 and the inner surface of the upper case 1a is prevented. The tiltable vertical gap, that is, the tilting gap E is set smaller than the vertical tilting gap e between the tips of the pair of lock teeth 19 and 20.
[0023]
When the reel 2 is driven to rotate, the lock release tool 18 rotates along with the reel 2, and the reel presser 16 continues to maintain a stationary state. For this reason, the ball 26 held in the socket portion 25 rotates due to a slight deviation of the rotation center axis, or remains stationary. Thus, since the ball 26 rotates relative to the unlocking tool 18 to release the relative friction, the frictional resistance between the two 18 and 16 can be reduced. Wear during long-term use can be suppressed to a negligible level.
[0024]
In the above embodiment, the ball 26 is press-fitted to the socket portion 25, but this is not necessary. For example, the socket portion 25 can be formed in a cylindrical shape, and the ball 26 loaded therein can be retained by a retaining ring. The socket portion 25 is formed as a separate part, and this is press-fitted to the reel retainer 16 so that the ball 26 can be rotatably held between the socket portion 25 and the base wall 21. The balls 26 can be formed of a durable plastic material such as polyacetal, polyamide resin, or polyethylene terephthalate.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an unlocked state of a reel lock mechanism.
FIG. 2 is an internal plan view of the tape cartridge.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is an exploded perspective view of a reel lock mechanism.
5 is a cross-sectional view taken along line BB in FIG.
6 is a view taken along the line CC in FIG. 3. FIG.
FIG. 7 is a cross-sectional view of a socket portion.
FIG. 8 is a longitudinal sectional view showing a comparative example of a reel lock mechanism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Case main body 2 Reel 12 Boss 15 Guide protrusion 16 Reel presser 17 Spring 18 Lock release tool 19/20 Lock tooth 25 Socket part 26 Ball

Claims (4)

Inside the box-shaped case body (1), one reel (2) wound with a magnetic tape (3) is arranged,
A reel lock mechanism is provided between the inner bottom of the boss (12) provided at the center of the reel (2) and the upper wall of the case body (1) to prevent the reel (2) from rotating freely when not in use. A magnetic tape cartridge provided,
The reel lock mechanism is slidable up and down by a guide projection (15) provided on the inner surface of the upper wall of the case body (1), but is engaged and guided so that relative rotation is impossible. A spring (17) that presses down and presses the presser foot (16), and is provided on opposing surfaces of the lower surface of the reel presser (16) and the upper surface of the bottom wall of the boss (12). Lock teeth (19) and (20) for preventing rotation of
Between the reel presser (16) and the bottom wall of the boss (12), the drive shaft (D) is pushed up to unlock the reel presser (16) against the biasing force of the spring (17). An unlocking tool (18) is arranged,
The ball (26) is rotatably held on the lower surface of the reel presser (16),
A horizontal joint (30) for receiving the ball (26) is formed at the center of the main surface wall (27) of the unlocking tool (18),
A single reel type magnetic tape cartridge in which a reel presser (16) and a lock release tool (18) are joined via a ball (26) so as to be relatively rotatable. The joint (30) is formed to bulge upward,
The base wall (21) of the reel presser (16) facing the bottom wall of the boss (12) is provided with a socket part (25) having a cross-sectional arc shape.
The single reel type magnetic tape cartridge according to claim 1, wherein the ball (26) is press-fitted to the socket portion (25) so as to be rotatable. The unlocking tool (18) is formed of a metal plate press-molded product,
3. A single reel type magnetic tape cartridge according to claim 2, wherein the ball (26) comprises a steel ball. 4. A single reel type magnetic tape cartridge according to claim 2, wherein a rotation receiving surface (25a) for receiving the peripheral surface of the ball (26) is formed in a circular shape on the inner surface of the socket portion (25).

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