JPH087404A - Reel stand rotation detection device - Google Patents

Abstract

(57) [Abstract] [Object] An object of the present invention is to provide a rotation detecting device for a reel base used in a video tape recorder or the like, which realizes a reduction in the number of parts and a cost reduction. [Structure] Reel gears 3 and 4 meshing with supply-side and take-up-side reel bases 1 and 4 periodically receive the amount of light from a light emitting element 5 with respect to a first light receiving element 6 and a second light receiving element 7, respectively. It has a changing structure. A light emitting element 5 and a first
The light receiving element 6 and the second light receiving element 7 are integrally formed by resin molding and are positionally regulated by the respective rotation center axes of the reel gears 3 and 4, and one light emitting element 5 and two light receiving elements 6 are provided. , 7 for detecting the rotations of the supply-side and take-up-side reel bases 1 and 2, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reel base rotation detecting device used in a magnetic recording / reproducing device such as a video tape recorder (hereinafter referred to as VTR).

[0002]

2. Description of the Related Art In a conventional magnetic recording / reproducing apparatus, many reel stand rotation detecting devices have been devised for controlling the reel stand by detecting the state of the tape winding diameter (for example, Japanese Laid-Open Patent Publication No. 62-62-62). 290334).

A conventional reel stand rotation detecting device will be described below with reference to the drawings. FIG. 5 shows an example of a conventional reel stand rotation detection apparatus, which is an apparatus using a reflection type optical sensor. FIG. 6 is a sectional view showing a driving force transmission system of a conventional reel stand. In FIG. 5, a flat reflecting surface 21e is formed on the bottom surface (lower surface in FIG. 5) of the reel stand 21. A circular reflection sheet 22 is attached to the reflection surface 21e. On the reflective sheet 22, white (reflective portions) and black (non-reflective portions) patterns are alternately formed at predetermined intervals in a radial pattern centered on the center point. The light emitting element 24 is connected to the control circuit 23. The light emitting element 24 is arranged at a position facing and close to the reflection sheet 22 of the reel stand 21. The light from the light emitting element 24 is applied to the reflection sheet 22 at a predetermined angle. This angle is set so that the reflected light is received by the light receiving element 25 described later. When the reflection sheet 22 is irradiated with light, the white pattern formed on the reflection sheet 22 reflects the light, but the black pattern absorbs the light and hinders the reflection. That is, the reflected light is received by the light receiving element 25 arranged in the vicinity of the light emitting element 24 only when the white pattern is irradiated. The signal output from the light receiving element 25 is amplified by the amplifier 26 and then supplied to the control circuit 23. The control circuit 23 detects the presence / absence of rotation of the reel base 21 and performs control such as operating a clutch mechanism (not shown) almost at the same time as the rotation of the reel base 21 is stopped.

In the above structure, when the reel base 21 is rotated, the light reflected by the white pattern of the reflection sheet 22 is supplied to the light receiving element 25 in a predetermined cycle, so that the light receiving element 25 outputs light in a predetermined cycle. The frequency signal is output and supplied to the control circuit 23. On the other hand, when the reel base 21 stops rotating at the end of the tape, the control circuit 23 does not supply a frequency signal of a predetermined period, so that the control circuit 23 operates the clutch mechanism. That is, in FIG. 6, the idler 32 is separated from the peripheral surface of the rotor 21 a, and the rotational force of the flywheel 31 is not transmitted to the reel base 21. Therefore,
When the end of the tape is reached, the reel base 21 does not rotate, and there is no fear of applying excessive tension to the tape.

In the reel stand 21 shown in FIG.
21b is a felt ring, 21c is a reel table, and 21d.
Is a leaf spring, 21e is a reflecting surface, 21f is a coil spring, 21g is a reel hub, and 21h is a stopper.

In general, a rotation detecting device is provided on each of the reel bases on the winding side and the supplying side in order to protect the tape against the end of the tape at the time of fast-forwarding / rewinding the tape and to judge the kind of the tape. By detecting the rotation of each reel stand, the acceleration / deceleration control of the reel stand according to the tape winding diameter condition is performed.

[0007]

However, in the conventional magnetic recording / reproducing apparatus as described above, the tape winding side,
Since a rotation detection device is required for each reel side on the supply side, not only the direct material cost and the number of parts increase, but also the man-hours for soldering terminals to the board according to the number of elements also increase, resulting in cost reduction. Was unsuitable. Further, it is necessary to mount two sensors each, and it is necessary to control the accuracy of the board, mechanical chassis, two sensor holders, and the like.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a low cost reel stand rotation detecting device.

[0009]

In order to achieve this object, a reel base rotation detecting device of the present invention comprises a light emitting element, a first light receiving element disposed so as to be able to receive the light of the light emitting element, and A second light receiving element which is arranged at a position different from that of the first light receiving element so as to be able to receive the light of the light emitting element, and a first light receiving element which changes the amount of light from the light emitting element periodically with respect to the first light receiving element. The supply-side rotating body that synchronizes with the rotation of the supply-side reel stand having the means or the supply-side reel stand having the first means, and the light amount from the light emitting element are periodically changed with respect to the second light receiving element. The winding side reel body having the second means or the winding side rotating body synchronized with the rotation of the winding side reel stand having the second means, and the light emitting element and the first and second light receiving elements. The holder that integrally holds the element is used to A configuration that is positioned regulated by each of the rotation center axis of the take-up reel table or the take-up rotor.

[0010]

In the above structure, the first light receiving element can detect the number of rotations of the supply-side reel stand by receiving the amount of light from the light-emitting element that periodically changes in synchronization with the supply-side reel stand. Similarly, the second light receiving element can detect the number of revolutions of the winding side reel stand by receiving the amount of light from the light emitting element which periodically changes in synchronization with the winding side reel stand. Therefore, one light emitting element and two light receiving elements can detect the rotation of the reel stand on each of the supply side and the winding side.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a reel base rotation detection device according to the present invention. FIG. 2 is a plan view of the reel base rotation detection device according to the present invention. FIG. 3 is a perspective view of the sensor holder according to the present invention.

In FIG. 1, the first light receiving element 6 is located on one side of the light emitting element 5, and the light emitting element 5 and a predetermined space 8 are provided.
Is provided so that the light of the light emitting element 5 can be received.
The second light receiving element 7 is arranged so as to be able to receive the light of the light emitting element 5 by providing the light emitting element 5 and a predetermined gap portion 9 on the side substantially opposite to the side on which the first light receiving element 6 is arranged. . Further, the light emitting element 5, the first light receiving element 6 and the second light receiving element 7 are the same as those in FIG.
The sensor holder 10 is integrated with the sensor holder 10 by resin molding, and each terminal has a substrate 11 arranged below.
It is fixed by soldering to. Further, the positioning hole 10a and the positioning long hole 10b (see FIG. 3) formed on the sensor holder 10 are fitted to the S reel gear shaft 13 and the T reel gear shaft 14 which are set up on the chassis 12, so that the sensor holder 10 is The substrate 11 is fixed to the chassis 12 while its position is regulated. The S reel gear 3 is rotatably supported by the S reel gear shaft 13. On the outer peripheral wall of the S-reel gear 3, there are slit portions in which a portion for transmitting the light from the light emitting element 5 to the first light receiving element 6 and a portion for not transmitting the light (9 portions in FIG. 2) are arranged at equal intervals. 3a is provided, and the slit portion 3a is arranged in the gap portion 8 so that the rotation of the S reel gear 3 can be detected, and meshes with the gear formed on the S reel base 1. Similarly, the T reel gear 4 is rotatably supported by the T reel gear shaft 14. On the outer peripheral wall of the T-reel gear 4, there are slit portions in which a portion for transmitting the light from the light emitting element 5 to the second light receiving element 7 and a portion for not transmitting the light (9 portions in FIG. 2) are arranged at equal intervals. 4a is provided, and the slit portion 4a is arranged in the gap portion 9 so that the rotation of the T reel gear 4 can be detected, and meshes with the gear formed on the T reel base 2.

The operation of the reel base rotation detecting device of the present embodiment having the above-described structure will be described below. Power from a drive source such as a capstan motor (not shown) is selectively transmitted to the S and T reel gears 3 and 4 in accordance with the running direction (each mode) of the tape, and the S reel base 1 or the T reel. The table 2 rotates in a predetermined direction and a tape (not shown) is driven. If the S reel gear 3 and the T reel gear 4 are rotating, the light from the light emitting element 5 is emitted from the slit portions 3a, 4a.
The first, while repeating transmission and shielding at a predetermined cycle by
Since it is supplied to the second light receiving elements 6 and 7, a frequency signal of a predetermined cycle is output from the first and second light receiving elements 6 and 7 and supplied to a control circuit (not shown), and the S reel stand 1 Predetermined control is performed on the T reel base 2.
During fast-forwarding / rewinding of the tape, acceleration / deceleration control of the S-reel base 1 or the T-reel base 2 is performed according to the winding diameter condition of the tape by using the output signals from the first and second light receiving elements 6 and 7. . That is, the S-reel base 1 or the T-reel base 2 is normally controlled at a predetermined speed after the speed-up control at the time of start-up. To be done. Also, when the S reel stand 1 and the T reel stand 2 stop rotating at the end of the tape, the control circuit (not shown) is not supplied with a frequency signal of a predetermined cycle, so that a control circuit (not shown) is provided. ) Stops the rotation of the drive source. At the same time, the types of tape cassettes having different tape lengths (recording time) are determined using the output signals of the first and second light receiving elements 6 and 7.

As described above, according to this embodiment, it is possible to detect the rotation of the pair of reel stands by one light emitting element and two light receiving elements, so that the number of parts can be reduced and the soldering accompanying the reduction of the light emitting elements can be performed. To realize a reel stand rotation detection device that is excellent in reducing man-hours such as work.

In this embodiment, the rotations of the S reel gear 3 and the T reel gear 4 are detected, but the present invention is not limited to this. Alternatively, the sensor holder 10 may be provided so that the rotation of the S reel base 1 and the T reel base 2 can be detected (not shown). Also,
The rotation detecting device of the present embodiment has a transmissive configuration, but FIG.
It may be of a reflection type as shown in FIG.

[0016]

As is apparent from the above description of the embodiments, the reel base rotation detecting device of the present invention includes a light emitting element, a first light receiving element arranged to receive light from the light emitting element, and a first light receiving element. 1
The second light receiving element, which is disposed at a position different from that of the light receiving element of FIG.
The supply side rotating body synchronized with the rotation of the supply side reel stand having the first means or the supply side reel stand having the first means, and the light quantity from the light emitting element. A take-up side reel body having a second means for periodically changing the light-receiving element, or a take-up side rotating body synchronized with the rotation of the take-up side reel stand having the second means. And a holder for integrally holding the light-emitting element and the first and second light-receiving elements are respectively rotated by the supply-side reel stand or the supply-side rotating body and the winding-side reel stand or the winding-side rotating body. By controlling the position by the central axis, it is possible to detect the rotation of a pair of reel stands with one light emitting element and two light receiving elements, reducing the number of parts and man-hours such as soldering work accompanying the reduction of light emitting elements. Is possible. Further, since the positioning accuracy of the sensor holder is improved, not only interference with the slit portion can be prevented, but also a stable output signal can be secured. Furthermore, since the space between the light emitting element and the light receiving element can be made small, the space efficiency of the mechanism is improved due to the miniaturization of the sensor section, and the degree of freedom in design is increased. A rotation detecting device for the reel stand can be realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a reel base rotation detecting device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a main part of the rotation detecting device of the reel stand.

FIG. 3 is a perspective view of a sensor holder in the rotation detection device of the reel base.

FIG. 4 is a perspective view of a main part of a reel base rotation detection device according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a conventional reel stand rotation detection device.

FIG. 6 is a cross-sectional view of a conventional reel base driving force transmission system.

[Explanation of symbols]

 1 S reel stand 2 T reel stand 3 S reel gear 3a Slit part 4 T reel gear 4a Slit part 5 Light emitting element 6 First light receiving element 7 Second light receiving element 8 Void 9 Void 10 Sensor holder 10a Positioning hole 10b Positioning length Hole 11 Substrate 12 Chassis 13 S reel gear shaft 14 T reel gear shaft

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiromi Amano 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A light emitting element, a first light receiving element arranged so as to be able to receive the light of the light emitting element, and light of the light emitting element can be received at a position different from that of the first light receiving element. A supply side reel stand having the second light receiving element disposed in the first light receiving element and the first means for periodically changing the amount of light from the light emitting element with respect to the first light receiving element, or the first means. A supply-side rotating body that is synchronized with the rotation of the supply-side reel stand, and a winding-side reel that includes second means for periodically changing the amount of light from the light-emitting element with respect to the second light-receiving element. A rotation detecting device for a reel base, comprising: a base or a winding-side rotating body that synchronizes with rotation of the winding-side reel base having the second means. 2. A holder for integrally holding one light emitting element and first and second light receiving elements is provided with the supply-side reel base or the supply-side rotating body, and the winding-side reel base or the winding. 2. The reel stand rotation detecting device according to claim 1, wherein the position is regulated by each rotation center axis of the take-side rotating body.