JPH08212628A - Falling preventing mechanism for reel base - Google Patents

Abstract

PURPOSE: To reduce the number of parts and to lighten rotational load imposed on a reel base in a falling preventing mechanism for reel base. CONSTITUTION: A locking piece 73 is projected from the lower surface of the reel base 2 and a pawl is provided at the edge of the locking piece 73. A flange 5 with which the pawl can be engaged is formed on a shaft 3 to which the reel base 2 is fitted. In a state where the lower surface of the reel base 2 is placed on the flange and the reel base 2 is attached to the shaft 3, the lower surface of the flange and the upper surface of the pawl are somewhat separated so as to prevent the reel base 2 from falling off from the shaft 3 and prevent the rotational load from being imposed on the reel base 2 because both surfaces are rubbed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus using a cassette containing a magnetic tape, and to a retaining mechanism for a reel stand for winding or sending out the magnetic tape.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus, a reel base (2) for winding a magnetic tape is rotatably mounted on a shaft (3) fixed on a chassis (1) as shown in FIG. It is common to be fitted. At the upper end of the reel stand (2), there is a fin (24) to which the hub of the cassette fits. If the reel base (2) is rotatably fitted to the shaft (3), the reel base (2) easily falls off the shaft (3) when an impact is applied from the outside. It is necessary to have a mechanism for preventing the shaft from easily escaping from the shaft (3). The reel base (2) retaining mechanism includes the following.

As shown in FIG. 7, a collar (5) is formed in the lower portion of the shaft (3) in contact with the upper surface of the chassis (1), and the collar (5) is loosely fitted to the shaft (3). A washer (4) is placed.
The washer (4) is made of graphite nylon, and the lower surface of the reel stand (2) contacts the washer (4) to reduce the rotational load. A retaining ring (40) is fitted to the upper end of the shaft (3) in contact with the upper surface of the reel stand (2), and the retaining ring (40) allows the shaft (3) of the reel stand (2) to move from the shaft (3). Is prevented from coming off. In addition, as a retaining mechanism for the reel base (2), as shown in FIG. 8, the tip of the shaft (3) is formed into a spherical surface, and the upper surface of the reel base (2) is closed to close the tip of the shaft (3). It is also practiced to provide a stopper (12) on the chassis (1) so as to abut on the chassis (1) and to face the upper surface of the outer peripheral portion of the reel stand (2).

As another retaining mechanism, a mechanism shown in FIGS. 9 and 10 has been proposed (JP-A-62-510).
No. 60). This is a sliding groove at the lower end of the shaft (3).
(30) is formed, and the sliding groove (30) is formed at the bottom of the reel stand (2).
Position the retaining ring (40) that fits in. The retaining ring (40) is mounted in the receiving portion (41) press-fitted on the lower surface of the reel base (2) with a margin in the vertical direction and the radial direction of the shaft (3). A screw (33) abutting on the tip of the shaft (3) is screwed onto the upper part of the reel base (2).

When the reel stand (2) is attached to the chassis (1), the reel stand (2) is fitted from above the shaft (3). The retaining ring (40) fits into the sliding groove (30) while opening the retaining portion (41) by a margin in the axial direction. The lower end of the screw (33) contacts the tip of the shaft (3). The reel stand (2) has a receiving part (4
Up and down play is allowed by the vertical gap between the retaining ring (40) and the retaining ring (40) to prevent retaining from the shaft (3). Reel stand
When the screw (33) is rotated while restraining the rotation of (2), the height of the reel stand (2) can be finely adjusted because the tip of the screw (33) is in contact with the shaft (3). The height adjusting mechanism is a reel stand (2)
Since it has nothing to do with the retaining mechanism, detailed description thereof will be omitted.

The applicant has previously proposed a mechanism for preventing the reel stand (2) from being pulled out as shown in FIG. 11 (see Japanese Utility Model Laid-Open No. 61-111043). This has a groove (30) at the upper end of the shaft (3) and a reel stand.
A through hole (29) fitted in the shaft (3) is formed in the center of (2). An elastically deformable locking piece (73) at the upper end of the through hole (29)
And a claw (74) is formed on the upper end of the locking piece (73). When the reel base (2) is fitted onto the shaft (3) and lowered, the locking piece (73) is elastically deformed, and the pawl (74) fits into the sliding groove (30).

[0007]

In the retaining mechanism shown in FIGS. 7 to 10, a retaining washer (40) and a retaining tool (12) are required to retain the reel base (2). The number of parts is increased as a whole structure. Further, in the configuration shown in FIG. 11, the claw (74) is engaged with the sliding groove (30), and
The lower surface of the and the lower end surface of the sliding groove (30) are in contact with each other. Therefore,
The reel base (2) rotates with the pawl (74) and the sliding groove (30) in contact with each other, which becomes a rotational load of the reel base (2). SUMMARY OF THE INVENTION It is an object of the present invention to reduce the number of parts and the rotational load on a reel stand in a reel stand-out prevention mechanism.

[0008]

[Means for Solving the Problem] The reel base retaining mechanism is
Locking piece having claw (74) from the lower surface of the reel stand (2) to the tip
(73) projects close to the shaft (3), and a small-diameter step portion that can engage with the claw (74) is formed on the lower peripheral surface of the shaft (3) so that the reel stand (2) can rotate the shaft (3). Attached to the lower surface of the small-diameter step and the claws (7
The upper surface of 4) is slightly separated. Further, another retaining mechanism is that the shaft (3) is made of an elastic body, and a washer (4) having a diameter larger than that of the shaft (3) is fitted at a position facing the lower surface of the reel base (2), While the reel stand (2) is attached to the shaft (3), the locking piece (73) having the claw (74) at the tip is projected from the lower surface of the stand (2) close to the outer circumference of the washer (4). , The washer
(4) The lower surface and the upper surface of the claw (74) are slightly separated.

[0009]

[Operation and Effect] With the reel base (2) attached to the shaft (3), the lower surface of the small-diameter step portion of the shaft (3) and the upper surface of the pawl (74) are slightly separated from each other. Therefore, when the reel base (2) rotates,
(74) and the lower surface of the peripheral portion of the shaft (3) are not rubbed against each other, and the reel base (2) is not given a rotational load. Further, since the pawl (74) is provided so as to be able to engage with the washer (4) made of an elastic body, when the reel stand (2) is attached to the shaft (3), the washer (4) is attached.
Can be elastically deformed and workability is improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. An 8 mm VTR is exemplified as the recording / reproducing apparatus. As shown in FIG. 1, this type of VTR is such that a reel chassis (1) on which a cassette (6) is to be mounted is slidable back and forth on a main chassis (9) on which a rotary cylinder (90) is mounted. It is provided in. In the cassette mounting position of the reel chassis (1), there are provided reel stands (2) and (2) to be fitted to the reels of the cassette (6), and the reel stands (2) and (2) are mounted on the reel chassis (1). )
Further, it is rotatably fitted on a shaft (3) fixed by crimping. Both reel stands (2) (2) are rotationally driven by an idler mechanism (8) provided between both reel stands (2) (2).

(First Embodiment) FIG. 2 is a cutaway view of the reel stand (2), FIG. 3 is an enlarged view of the essential parts thereof, and FIG. 4 is a perspective view of the reel stand (2). The reel stand (2) is generally used in a recording / reproducing apparatus such as an 8 mm VTR that is required to be downsized, and is of a type that incorporates a slip mechanism. Reel stand
(2) is an upper reel stand (20) with a gear part (20a) formed on the outer periphery.
And a press-fitting piece (7) provided with a protruding shaft (70) in the central portion thereof, and a cylindrical shaft (21) projects upward from the central portion of the upper reel stand (20). At the center of the cylindrical shaft (21), a first hole (22) slightly larger than the diameter of the shaft (3) and a protruding shaft of the press-fitting piece (7) continuous to the lower side of the first hole (22). The second hole (23) into which the (70) is press fitted is opened. A through hole (71) having the same diameter as the first hole (22) is formed in the center of the salient shaft (70). A fin (24) is fitted on the cylinder shaft (21) so as to be vertically slidable. The fin (24) is urged upward by a compression spring (26) wound around the cylinder shaft (21),
The upward movement is restricted by the restricting piece (27) protruding from the (21).

A gear plate (25) having substantially the same diameter as that of the gear portion (20a) of the upper reel stand (20) is rotatably fitted to the lower end portion of the protruding shaft (70) so that the gear plate (25) and the upper portion of the gear plate (25). The gear plate (25) is urged downward by the compression spring (28) mounted between the gear plate (25) and the reel stand (20). The felt (72) is placed on the upper surface of the press-fitting piece (7), and the gear plate (25) is pressed against the felt (72) by the compression spring (28). When the gear plate (25) is rotated by the idler mechanism (8), a rotational torque is generated due to the rotational friction between the felt (72) and the gear plate (25). Such torque is transmitted to the upper reel stand (20) via the press-fitting piece (7), and the magnetic tape in the cassette is smoothly wound up.

As shown in FIG. 3 (a), the shaft (3) has a collar (5) at its lower end as in the conventional case. Above the tsuba (5), the shaft
A washer (4) loosely fitted in (3) is placed, and the washer (4) is placed.
(4) The bottom surface of the reel stand (2) is in contact with the top. The collar (5) is continuous with the small diameter step shaft (50) formed below, and the lower surface of the step shaft (50) is in contact with the surface of the chassis (1). From the lower surface of the press-fitting piece (7), a locking piece (73) having a claw (74) at its lower end projects downward.
The claw (74) has a flat surface (74a) that extends horizontally inward and a flat surface.
An inclined surface (74b) inclined downward from the edge of (74a) is integrally provided. The distance L from the edge of the flat surface (74a) to the central axis of the through hole (71) is shorter than the radius of the collar (5).

When the reel stand (2) is attached to the main chassis (1), the through hole (71) is fitted on the shaft (3), and the reel stand (2) is attached.
Lower (2) along axis (3). The first hole (22) of the upper reel stand (20) fits on the shaft (3). When the reel stand (2) is further lowered, as shown in FIG. 3 (b), the inclined surface (74b) of the claw (74)
Comes into contact with the outer peripheral edge of the collar (5), and the locking piece (73) opens outward.
When the pawl (74) passes through the collar (5), the locking piece (73) elastically returns, and the flat surface (74a) is slightly separated from the lower surface of the collar (5), and the lower surface of the reel stand (2). Is placed on the washer (4). Therefore, the reel base (2) is prevented from coming off the shaft (3) by the claw (74) and the collar (5). Since the pawl (74) is slightly separated from the collar (5), the pawl (74) is rotated when the reel base (2) is rotated.
There is no sliding load due to the friction between the reel and the collar (5), and the reel stand (2)
Can rotate smoothly.

Below the pawl (74), the chassis (1) has a hole (1
0) has been opened. Shaft (3) to replace reel stand (2)
To remove it from the bottom, first insert a jig (11) such as a driver from the lower side of the hole (10) and open the locking piece (73) outward. In this state, pull the reel stand (2) upwards
(2) can be pulled out from the shaft (3). In addition, as described above, since the reel chassis (1) can be pulled out forward, a sufficient space can be obtained for inserting the jig. In the above embodiment, the reel base (2) is placed on the washer (4) to reduce the rotational load of the reel base (2).
As shown in Fig. 8, the tip of the shaft (3) is made spherical and the reel stand
The retaining mechanism can be applied even if the rotation load of the reel base (2) is reduced by closing the upper surface of (2) and contacting the tip of the shaft (3).

(Second Embodiment) As shown in FIG. 5, a reel stand
The shaft (3) into which the (2) is fitted is a slender upper shaft (31) and an upper shaft (3
A lower shaft (32) slightly larger than 1) is integrally provided. Lower shaft
A collar (5) contacting the chassis (1) is formed at the lower end of the (32), and a slit (30) for fitting the washer (4) is formed at the center of the lower shaft (32). There is. The washer (4) is made of an elastic material such as graphite nylon and has a shaft similar to that described above.
Although it is inserted from above (3), since the upper shaft (31) is thin,
Easy to insert washer (4).

Similar to the above embodiment, a locking piece (73) projects from the lower surface of the reel base (2) (see FIG. 6). Fit the reel stand (2) onto the shaft (3) and lower it, and the pawl (74) should be
The locking piece (73) elastically returns in the state of passing through (4). The lower surface of the reel stand (2) contacts the upper surface of the washer (4) with the flat surface (74a) slightly separated from the lower surface of the washer (4). In this way, the reel stand (2) is prevented from slipping off the shaft (3). In the present embodiment, the locking piece (73) is engaged with the washer (4) on which the reel base (2) is placed, and by inserting the washer (4) having a different outer diameter, the pawl ( It is possible to change the engagement margin of 74). Further, not only the locking piece (73) but also the washer (4) is formed of an elastic body, so that when the reel stand (2) is attached to the shaft (3), the washer (4) is
(4) can also be elastically deformed, which improves workability.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[Brief description of drawings]

FIG. 1 is a plan view of a main chassis and a reel chassis.

FIG. 2 is a cutaway view of a reel stand attached to a shaft.

3 (a) and 3 (b) are partially cutaway views showing a state in which a reel stand is attached to a shaft, and FIG. 3 (c) is a partially cutaway view showing a state in which a reel stand is attached to a shaft.

FIG. 4 is a perspective view of a reel stand.

FIG. 5 is a cutaway view of a reel stand according to another embodiment.

FIG. 6 is a cross-sectional view of an essential part of the above.

FIG. 7 is a cutaway view of a conventional reel stand mounted on a shaft.

FIG. 8 is a cutaway view showing a state in which another conventional reel stand is attached to a shaft.

FIG. 9 is an exploded perspective view showing a state in which another conventional reel stand is attached to a shaft.

FIG. 10 is a cutaway view showing a state where the above reel stand is attached to a shaft.

FIG. 11 is an exploded view of a state in which another conventional reel stand is attached to a shaft.

[Explanation of symbols]

 (1) Chassis (2) Reel stand (3) Shaft (4) Washer (73) Locking piece (74) Claw

Claims (2)

[Claims] 1. A reel base (2) for preventing a reel base (2) rotatably fitted on a shaft (3) erected on a chassis (1) from falling off the shaft (3). In the stopping mechanism, a locking piece having a claw (74) at the tip from the lower surface of the reel stand (2)
(73) projects close to the shaft (3), and a small-diameter step portion that can engage with the claw (74) is formed on the lower peripheral surface of the shaft (3) so that the reel stand (2) can rotate the shaft (3). Attached to the lower surface of the small-diameter step and the claws (7
A mechanism for preventing the reel stand (2) from coming off, characterized in that the upper surface of 4) is slightly separated. 2. A reel base (2) is removed to prevent a reel base (2) rotatably fitted on a shaft (3) erected on a chassis (1) from falling off the shaft (3). In the stopping mechanism, a washer (4) made of an elastic body and having a diameter larger than that of the shaft (3) is fitted to the shaft (3) at a position facing the lower surface of the reel stand (2).
Locking piece having claw (74) from the lower surface of the reel stand (2) to the tip
(73) projects close to the outer periphery of the washer (4) and
With the washer (2) attached to the shaft (3), the washer (4)
A mechanism for retaining the reel base (2), wherein the lower surface and the upper surface of the claw (74) are slightly separated from each other.