JP2875528B2 - Reel stand brake device for magnetic recording and reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention applies a load to a take-up or supply reel table in a magnetic recording / reproducing apparatus to apply a back tension to a tape wound around the pair of reel tables. The present invention relates to a reel base brake device provided. [Summary of the Invention] The present invention relates to a reel stand brake device for a pair of reel stands in a magnetic recording / reproducing apparatus, wherein a first gear provided on at least one of the pair of reel stands, and a limiter clutch is provided on the first gear. A second gear provided via a second gear, a third gear meshed with the second gear, a fourth gear provided on the third gear via a one-way clutch comprising a ball, And a stopper having a claw portion detachably provided with the fourth gear so as to be separated from the fourth gear during the loading, so that the FWD system mode at the time of tape recording, reproduction, etc. At the same time, one of the reel bases can be rotated with substantially no load, and a speed load is applied to the one reel base during the RVS mode such as when rewinding the tape. Reel stand empty It is obtained to be able to suppress Ri. 2. Description of the Related Art For example, in a video tape recorder (VTR) as a magnetic recording / reproducing apparatus, when a magnetic tape is rewound, an appropriate load is applied to a take-up reel table, and extra tape caused by idling of the take-up reel table. And a reel base brake device for preventing the drawer from being pulled out. Referring to FIGS. 4 and 5, reference numeral 1 denotes a chassis rotatably supporting a rotary head drum (not shown). On the chassis 1, a take-up reel base 2 and a supply reel base 3 are provided at predetermined intervals with respective spindles 4, 5.
It is rotatably supported via. Each of these reel stands 2,
Gears 6 and 7 are provided on the lower surface side of 3, respectively. These gears 6 and 7 mesh with a drive gear 8 linked to a motor (not shown), and form a swinging gear 10 which swings right and left in FIG. 4 around a support shaft 9 of the drive gear 8. By meshing, one of the reel bases 2 and 3 can be driven to rotate. Further, between the take-up reel base 2 and the gear 6,
The brake drum 12A is interposed via the clutch 11A. A pad 1 made of rubber or the like of a brake arm 14A biased by a spring 13A or the like is provided on an outer peripheral surface of the brake drum 12A.
5A is provided to be able to contact and separate. The brake drum 12A, the brake arm 14A and the like constitute a reel-unit brake device. When the video tape recorder, for example, rewinds a tape (in the RVS mode), the swing gear 10 is switched to mesh with the gear 7 of the supply reel base 3 so that the supply reel base 3 is engaged.
To rotate the brake drum 12A on the take-up reel base 2.
By applying an appropriate load (braking) to the take-up reel table 2 by bringing the pad 15A of the brake arm 14A into contact with the pad, the idling of the take-up reel table 2 at the time of rewinding the tape is suppressed and extra tape is used. Are not drawn out to the supply reel table 3 side. [Problems to be Solved by the Invention] In recent years, it has been desired to reduce the thickness and weight of a video tape recorder. However, the reel stand brake device in the conventional video tape recorder employs a gear for rotating the take-up reel stand 2. 6 and take-up reel base 2 when rewinding tape
And the brake drum 12A that applies braking to the gear reel 2 has a two-tier structure, so that the height from the upper surface of the take-up reel base 2 to the lower surface of the gear 6 (indicated by reference numeral H in FIG. 5) is increased. There was a drawback, and it was not possible to reduce the thickness of the device by the height of the brake drum 12A. Also, the operation mode of the reel stand brake device is distinguished between the RVS system mode and the FWD system mode, and the take-up reel base 2 is braked only in the RVS system mode. , Brake arm 14A
Since a large number of mechanical and electrical parts for driving the components are required, and the number of parts increases accordingly, there has been a problem that their mechanisms and processing become complicated. In addition, since a load is applied to the outer peripheral surface of the brake drum 12A by a pad 15A made of rubber or the like,
The fluctuation of the torque due to the wear of the pad 15A or the like causes the stability of the brake torque to be low, and there is a problem that the management of the torque is difficult. Accordingly, the present invention provides a reel stand brake device of a magnetic recording / reproducing apparatus which can always obtain a stable brake torque characteristic only when a braking force is required on the reel stand with low cost, space saving and power consumption. It is. [Means for Solving the Problems] A first gear provided on at least one of a pair of reel stands of a magnetic recording / reproducing apparatus, a second gear provided on the first gear via a limiter clutch, A third gear meshed with the second gear, a fourth gear provided on the third gear via a one-way clutch made of a ball, and separated from the fourth gear at the time of stopping and during loading. And a stopper having a claw portion, which is provided so as to be freely disengageable with the fourth gear. [Operation] A first gear provided on at least one of the pair of reel bases and a second gear provided via a limiter clutch mesh with a third gear, and a FW for recording and reproducing a tape.
In the D-system mode, the third gear rotates together with the first gear of the one reel base under substantially no load. In the RVS mode such as when the tape is rewound, the one-way clutch stops the fourth gear, and the third gear does not rotate. As a result, the second gear engaged with the third gear stops, and at this time, an appropriate load torque is applied to the first gear by the action of the limiter clutch interposed between the second gear and the first gear. In addition, idle rotation of the reel base is suppressed. As a result, the thickness of the portion corresponding to the conventional brake drum is eliminated, and the device is correspondingly thinned. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 3 show a case where the present invention is applied to a video tape recorder (VTR) as a magnetic recording / reproducing apparatus. A take-up reel base 2 and a supply reel base are provided on a chassis 1 at predetermined intervals. 3 are rotatably supported via the respective support shafts 4 and 5, and the gears 6 and 7 provided on the lower surface side of the respective reel bases 2 and 3 are centered on the support shaft 9 of the drive gear 8. This is similar to the above-described conventional one in that one of the reel bases 2 and 3 is rotatably driven by meshing with a swinging gear 10 that swings left and right. Here, below the gear 6 (first gear) of the take-up reel base 2, a gear 12 (second gear) is rotatably supported by the support shaft 4 via a plate-shaped limiter clutch 11. I have. The limiter clutch 11 is mounted on the take-up reel base 2.
A disk-shaped magnet 13 fixed to the lower surface of the gear 12 and a metal disk 14 forming the body of the gear 12 opposed to the magnet 13 via a predetermined clearance. When the gear 12 is stopped by an input gear 18a (third gear) of a gear 18 having a one-way clutch 17 described later, the gear 6 of the take-up reel base 2 is appropriately braked. At a position near the take-up reel base 2 of the chassis 1, a support shaft 15 is provided upright at a predetermined distance from the support shaft 4 of the take-up reel base 2, and a long hole 16 is formed. It is formed. The support shaft 15 has a gear 18 having a one-way clutch 17 which meshes with the gear 12 below the take-up reel base 2.
Is rotatably supported. The gear 18 is composed of an input gear 18a meshing with the gear 12 of the take-up reel base 2, and an output gear 18b (the first gear 18b) laminated on the input gear 18a via the well-known one-way clutch 17 composed of a ball 17a or the like. 4 gear). When the one-way clutch 17 stops the output gear 18b at the claw portion 20a of the stopper 20, which will be described later, the input gear 18a rotates only in the counterclockwise direction in the figure. The stopper 20 is rotatably supported via a pin 21 on the lower surface of the chassis 1 near the slot 16.
The stopper 20 is formed in a substantially L-shape, and a claw portion 20a at one end thereof is projected from the long hole 16 to the upper surface of the chassis 1 so as to be freely detachable from the output gear 18b. That is, the other end 20b side of the stopper 20 is urged by the spring 22 in a direction in which the claw portion 20a is separated from the output gear 18b, and the intermediate portion 20c is linked to a driving mechanism (not shown) including a cam or the like. Spring the stopper 20 around the pin 21
It is designed to rotate against the biasing force of 22. The rotation of the stopper 20 causes the RV during tape rewind
The claw 20a of the stopper 20 is locked by the output gear 18b in the S-system mode and in the FWD system mode such as recording, reproduction, and quick return, while the claw 20a of the stop 20 is stopped by the output gear 18b at the time of stopping and during loading. It is set apart from 18b. The gear 18 having the one-way clutch 17, the stopper 20 and the gear 12 having the limiter clutch 11 of the take-up reel base 2 constitute a reel base brake device in a video tape recorder. Reference numeral 30 denotes a cassette, 31 denotes a take-up reel of the cassette 30, 32 denotes a supply reel of the cassette 30, and 33 denotes a tape. According to the apparatus of the embodiment described above, when the tape 33 of the cassette 30 mounted on each of the reel bases 2 and 3 of the video tape recorder is rewound to the supply reel 32, the claw portion 20a of the stop 20 is pressed by the drive mechanism. The gear 18 having the direction clutch 17 is engaged with an output gear 18b. From this state, when the tape 33 is rewound (running the tape 33 in the RVS direction) by a capstan (not shown) or the like, the rotation of the output gear 18b is stopped by the claw portion 20a of the stopper 20, and The input gear 18a is not rotated by the direction clutch 17. As a result, the gear 12 below the take-up reel base 2 engaged with the input gear 18a stops. At this time, due to the magnetic force of the magnet 13 of the limiter clutch 11 interposed between the gear 6 of the take-up reel base 2 and the gear 12 therebelow,
An appropriate load torque is applied to the gear 6. As a result, the take-up reel base 2 is braked at a speed, so that the take-up reel base 2 can be prevented from running idle when the tape 33 is rewound, so that the tape is unnecessarily necessary.
33 is not pulled out to the supply reel 32 side. Thus, the gear 12 provided on the take-up reel base 2
The gear 18 having the one-way clutch 17 is meshed with the reel unit brake device, and the reel unit brake device is expanded in the lateral direction of the chassis 1, thereby increasing the thickness of the take-up reel unit 2 in the vertical (height) direction. Since there is no need to provide a thin brake drum or the like, the thickness of the take-up reel base 2 in the height direction can be reduced, and the entire apparatus can be made thinner. Further, since the braking (brake) torque generated on the take-up reel base 2 is based on the magnetic force of the magnet 13 and the like, a stable brake torque can be always obtained, and wear and the like are taken into consideration as in the conventional pad 15A. Since it is not necessary, the management for maintaining the brake torque is very easy. FWD for recording and playback of video tape recorders
When the tape 33 runs in the direction (at the time of the FWD system mode), the swing gear 10 is switched and meshed with the gear 12 of the take-up reel base 2. At this time, the claw portion 20a of the stopper 20 is locked to the output gear 18b as described above. When the take-up reel base 2 is rotated clockwise in the drawing from this state, the input gear 18a of the gear 18 having the one-way clutch rotates only in one direction counterclockwise. The upper gear 6 rotates with the gear 12.
As a result, an extra load is hardly applied to the take-up reel base 2 and power consumption is reduced. Also, the claw portion 20a of the stopper 20 is in the RVS mode, FWD
Regardless of the system mode switching, the gear 18 having the one-way clutch 17 is always locked to the output gear 18b, and switching operation or the like according to each mode is unnecessary. The number of electrical parts can be reduced, and the structure of the entire brake device and its processing can be simplified. According to this embodiment, a gear 18 having a one-way clutch 17 is provided on the take-up reel table 2 side to prevent the take-up reel table 2 from running idle when rewinding the tape. It may be provided on the side to suppress idle rotation of the supply reel table 3 to prevent the extra tape from being pulled out. Also, the case where the magnetic recording / reproducing apparatus is applied to a video tape recorder has been described. However, the present invention is not limited to this, and it is needless to say that the present invention can be applied to a cassette tape recorder. [Effects of the Invention] As described above, according to the present invention, the first gear provided on at least one of the pair of reel stands of the magnetic recording / reproducing apparatus, and the first gear provided via the limiter clutch. A second gear, a third gear meshed with the second gear, a fourth gear provided on the third gear via a one-way clutch made of a ball, By having a stopper having a claw portion detachably provided with the fourth gear so as to be separated from the fourth gear, the respective reel bases can be moved during the RVS direction running such as when the tape is rewound. An appropriate load is applied to at least one of the reel bases to suppress idle rotation of the reel bases, thereby preventing extra tape from being pulled out, and reducing the thickness of the reel bases in the height direction to reduce the overall thickness of the apparatus. Can be further promoted it can. Further, only by keeping the second gear and the third gear provided on the first gear of the reel base via the limiter clutch in mesh with each other, it is possible to switch each mode to the RVS mode or the FWD mode. Since it is unnecessary, the number of parts can be reduced correspondingly, the structure and electric processing can be further simplified, and a stable braking torque can be obtained by power saving.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 3 show an embodiment of the present invention. FIG. 1 is an exploded perspective view of a main part of a magnetic recording / reproducing apparatus, and FIG. 2 is a plan view of the same. FIG. 3 is a sectional view of the same, FIG. 4 is a plan view of a conventional example, and FIG. 5 is a side view of the conventional example. 2,3 ... Supply reel base, 12 ... Gear, 17 ... One-way clutch, 18 ... Gear.

Claims (1)

(57) [Claims] A first gear provided on at least one of a pair of reel stands of the magnetic recording / reproducing apparatus; a second gear provided on the first gear via a limiter clutch; and a third gear meshed with the second gear. A fourth gear provided on the third gear via a one-way clutch made of a ball; and a fourth gear, which is separated from the fourth gear during stop and during loading. I was provided so that it could be disengaged,
A reel stand brake device for a magnetic recording / reproducing device, comprising: a stopper having a claw portion.