JP2803387B2 - Clutch mechanism of magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the construction of a clutch mechanism for automatically switching supply or take-up of a magnetic tape in a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art Generally, the supply or take-up of a magnetic tape in a magnetic recording / reproducing apparatus is performed by transmitting the rotation of a motor by a timing belt and switching a clutch mechanism to a supply gear or a take-up gear. Hereinafter, a clutch mechanism in a conventional magnetic recording / reproducing apparatus will be described.

FIG. 3 shows a sectional view of a conventional clutch mechanism. In FIG. 3, reference numeral 1 denotes a fixed stay, both ends (one end of which is not shown) are firmly fixed on a fixed base 3 by screws 2, and a central part is fixedly formed by a pin member. It constitutes the shaft portion 4 of the entire clutch mechanism. Reference numeral 5 denotes an idler arm on a U-shaped flat plate. Both ends (one end is not shown) support an idler gear 6 for winding and an idler gear 7 for supply. A boss 8 as a bearing portion is formed so that the portion 4 can be mounted, and the idler arm 5 can rotate about the shaft portion 4. Numeral 9 is a center gear having tooth shapes 9a and 9b on different outer peripheral portions for transmitting rotation of a motor (not shown) by a timing belt 10 and transmitting the rotation to a winding idler gear 6 and a supply idler gear 7. The end portion is supported by the stopper plate 11 and the screw 12, and can be rotated around the shaft portion 4 of the fixed stay 1.

The operation of the clutch mechanism configured as described above will be described below with reference to FIG. In FIG. 4, reference numeral 41 denotes a cassette such as a C cassette accommodating a magnetic tape 42 therein. First, when the magnetic tape 42 is wound, as shown in FIG. The tooth profile of the winding drive gear 43 is engaged. Here, when a motor (not shown) is driven, the timing belt 10 moves in the direction of arrow A, and accordingly, the center gear 9 rotates counterclockwise (counterclockwise), and the winding idler gear 6 is rotated. The drive drive gear 43 for winding is driven via this. Next, when the magnetic tape 42 is supplied for recording and reproduction, FIG.
As shown in (b), the clutch is switched so that the tooth shapes of the supply idler gear 7 and the supply drive gear 44 mesh with each other, and the timing belt 10 is moved in the direction of arrow B by driving a motor (not shown), thereby the center is moved. The gear 9 rotates clockwise (clockwise), drives the supply drive gear 44 via the supply idler gear 7, and rotates the supply reel base 45.

[0005]

However, in the above-described conventional configuration shown in FIG. 3, the boss 8 of the idler arm 5 is not fixed when the center gear 9 rotates, and the bearing 9 of the center gear 9 moves. Near the center gear 9
The gap A between the bearing 9 'of the center gear 9 and the outer periphery 8' of the boss 8 and the gap B between the shaft 4 of the fixed stay 1 and the inner periphery 8 "of the boss 8 exist. In the vicinity of 9 ', there is eventually a gap (A + B), which is a combination of the gap A and the gap B, which causes surface wobbling when the center gear 9 rotates. First, the timing belt 10
Causes a derailment when the center gear rotates, the second problem is a gap between the winding idler gear 6 and the center gear 9,
In addition, it is necessary to increase the gap between the supply idler gear 7 and the center gear 9 so that the influence of surface fluctuation of the center gear 9 does not affect each of the gears 6 and 7.

Third, if the tooth thickness of the center gear 9 is reduced, the surface runout becomes severe. Therefore, the tooth thickness is required to be a certain degree or more, and there is a problem that it is not suitable for reducing the thickness of the entire clutch mechanism. An object of the present invention is to solve the above-mentioned conventional problem, and to provide a clutch mechanism of a magnetic recording / reproducing apparatus capable of suppressing surface fluctuation during rotation of a center gear 9 and realizing a thin clutch mechanism as a whole. And

[0007]

In order to achieve this object, a clutch mechanism according to the present invention forms a boss as a bearing for an idler arm at the center of a fixed stay having both ends fixed, and fixes the boss. It has a configuration in which a center gear bearing is mounted as a shaft and the center gear is rotated.

[0008]

According to this structure, the boss of the fixed stay is fixed as a shaft of the center gear without being moved, so that a gap which causes surface fluctuation of the center gear is formed between the bearing portion of the center gear and the outer peripheral portion of the boss. Only the gap, the gap near the center gear bearing is smaller than before,
For this reason, surface blur can be suppressed. Further, by suppressing the surface fluctuation of the center gear, the gap between the center gear and the take-up idler gear and the supply idler gear can be reduced, and the tooth thickness of the center gear can be reduced. Can be made thinner.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 11 denotes a fixed stay,
Both ends (one end is not shown) are fixed on a fixing base 13 by screws 12, and have a boss 14 at the center to constitute a bearing. Reference numeral 15 denotes an idler arm on a U-shaped flat plate. The idler arm 16 supports a winding idler gear 16 at one end and a supply idler gear 17 at the other end, and a shaft portion fixedly formed by a pin member at the center. 18
And the shaft 18 is mounted on the boss 14 of the fixed stay 11. Reference numeral 19 denotes a center gear, which has tooth shapes 19a and 19b for transmitting the rotation of the motor transmitted by the timing belt 20 to the take-up idler gear 16 and the supply idler gear 17, as shown in FIG.
It is provided on a different outer peripheral portion, and its end is supported by a stopper plate 21 and a screw 22, so that it can rotate about the boss 14 of the fixed stay 11 as an axis.

The operation of the clutch mechanism of the magnetic recording / reproducing apparatus configured as described above will be described with reference to FIG. In FIG. 2, reference numerals 41 to 45 are the same as those of reference numerals 41 to 45 shown in FIG.

FIG. 2A shows the positional relationship between the clutch and the gear when the tape is wound. When the tape is wound, the tooth forms of the winding idler gear 16 and the winding drive gear 43 mesh with each other. To do. Here, when the motor (not shown) is driven to move the timing belt 20 in the direction of arrow A, the center gear 19
Rotates counterclockwise around the boss 14 of the fixed stay 11 to drive the winding drive gear 43 via the winding idler gear 16, and the magnetic tape 42 is automatically wound. FIG. 2B shows the positional relationship between the clutch and the gear during tape supply. When the magnetic tape 42 is supplied, the clutch is set so that the tooth shapes of the supply idler gear 17 and the supply drive gear 44 mesh with each other. Switch. When the clutch is switched, the rotation of the take-up idler gear 16 and the center gear 19 is suppressed by the vertical pressing force of the spring 23 provided inside the take-up idler gear 16, and the movement of the timing belt 20 is taken up. With the operation of switching from the direction to the supply direction (from arrow A to arrow B), the idler arm 15
This is done by rotating clockwise about 8.
When the clutch switching is completed, a motor (not shown)
Rotates in the direction opposite to the winding direction, and accordingly, the timing belt 20 starts moving in the direction of arrow B in FIG. 2B, and the center gear 19 rotates clockwise about the boss 14 (clockwise). , And drives the supply drive gear via the supply idler gear 17.

As described above, according to this embodiment, the boss 14 is formed at the center of the fixed stay 11 having both ends fixed, and the center gear 19 is rotated with the boss 14 as a fixed shaft. Therefore, the gap existing near the bearing of the center gear 19 is
Only the gap formed between 9 'and the outer peripheral portion 14' of the boss 14 makes it possible to suppress surface fluctuation during rotation of the center gear 19 as compared with the related art.

Further, since the surface fluctuation during rotation of the center gear 19 is suppressed, the gap between the center gear 19 and the winding idler gear 16 and the gap between the center gear 19 and the supply idler gear 17 can be reduced. Further, since the tooth thickness of the center gear 19 can be made smaller than before, the thickness of the entire clutch mechanism can be reduced.

[0015]

As described above, the present invention employs a configuration in which a boss is formed at the center of a fixed stay to which both ends are fixed, and the boss is used as a fixed shaft to mount a bearing of a center gear. The gap existing near the center gear receiving part of the center gear is smaller than before, so that the center gear can be prevented from shaking when rotating, and the gap between the center gear, the take-up idler gear and the supply idler gear is reduced. This makes it possible to realize a clutch mechanism of an excellent magnetic recording / reproducing apparatus in which the thickness of the center gear can be reduced and the overall thickness of the clutch mechanism can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a clutch mechanism of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2A is a diagram illustrating a positional relationship between a clutch and a gear during winding of a magnetic tape according to an embodiment of the present invention; and FIG. 2B is a diagram illustrating a positional relationship between a clutch and a gear during supplying a magnetic tape according to the embodiment.

FIG. 3 is a sectional view of a clutch mechanism of a conventional magnetic recording / reproducing apparatus.

FIG. 4A is a diagram illustrating a positional relationship between a clutch and a gear when a conventional magnetic tape is wound; and FIG. 4B is a diagram illustrating a positional relationship between a clutch and a gear when a conventional magnetic tape is supplied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Fixed stay 14 Boss 15 Idler arm 16 Idler gear for winding 17 Idler gear for supply 18 Shaft 19 Center gear 20 Timing belt 23 Spring

Claims (1)

(57) [Claims] 1. A fixed stay having both ends fixed and a boss formed at a center portion to form a bearing portion, a first idler gear for winding at one end and a second idler gear for supply at the other end. An idler arm having a shaft portion for mounting on the boss of the fixed stay, and a tooth profile on an outer peripheral portion for meshing with the first idler gear and the second idler gear. A clutch mechanism for a magnetic recording / reproducing apparatus, comprising: a center gear that is rotated by a timing belt that transmits rotation of a motor around the boss of the fixed stay.