JPH09138996A - Reel base braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a drawing load of a magnetic tape and to keep its tension by making a sliding lever provided with brakes to be in contact with cylindrical projections of reel bases give optimum rotational resistance to both reel bases at the time of drawing the tape. SOLUTION: Brake shoes 2 and 3 at the tips of brake levers 1a and 1b of the sliding lever 1, which are elastically deformed in the sliding direction are brought into contact with outer peripheries of the projecting parts 4a and 4b. The lever 1 is reversibly slid with an engagement pin 8 engaged with a cam groove 7 of a cam gear 6 to be turned by a motor 9, while the magnetic tape 12 is drawn out by the gear 6 with a tape drawing mechanism 13. The groove 7 is continuously changed in direction, so that when the lever is moved in the direction of D or E, elastic deforming amts. of the levers 1a and 1b are increased or decreased, and hence rotational resistance of both reel bases is increased or decreased. Thus, the optimum rotational resistance is obtained for the reel bases, and the operational load of the mechanism 13 is reduced, and then the tension of the tape 12 can optimally be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a video tape recorder for ejecting a magnetic tape from a cassette to a predetermined recording / reproducing position by means of a tape ejecting mechanism during the tape ejecting operation. The present invention relates to a reel stand braking device that applies a continuously changing rotation resistance to a reel stand to reduce the load of the drawing operation of a tape drawing mechanism and to maintain the tension of a magnetic tape.

[0002]

2. Description of the Related Art FIG. 6 shows the structure of a reel stand braking device in a conventional magnetic recording / reproducing apparatus, and FIG. 8 shows the change in the rotation resistance of the reel stand during the tape drawing process. The reel base braking device shown in FIG. 6 controls the rotation of the reel bases 4 and 5 by brake levers 14 and 15 rotatably attached to pins 20 and 21 planted and contacted with a substrate (not shown). Is. The brake levers 14 and 15 respectively have brake shoes 2 and 3 at their tips, and springs 16 and 17 for generating a braking force for the reel base cause the brake shoes 2 and 3 to constantly contact the outer circumferences of the reel bases 4 and 5, respectively. It is elastically biased in the contact direction. Then, the brake levers 14, 1
5 is a cam groove 1 in which the convex portions 2a and 3a provided on each are normally formed in the sliding lever 1 as shown by the solid line in FIG.
The sliding positions of the brake shoes 2 and 3 are regulated by slidably contacting them, so that the brake shoes 2 and 3 do not contact the reel bases 4 and 5.

On the other hand, the sliding lever 1 is decelerated by a motor 9 by a cam groove 7 provided in a cam gear 6 and a pin 8 which is planted in contact with the sliding lever 1 and slidably engaged with the cam groove 7. The rotation is converted into sliding, and the sliding movement is made with the rotation of the motor 9. When the magnetic tape is pulled out from the cassette, the sliding lever 1 slides due to the rotation of the motor 9, and the convex portions 2a and 3a of the brake levers 14 and 15 move to the sliding lever 1 as shown in FIG. When the cam grooves 1c and 1d are located in wide areas, the brake levers 14 and 15 start to rotate by the urging forces of the springs 16 and 17, respectively, and the reel stands 4, 5
It is configured to come into contact with and to obtain a predetermined constant braking force.

The brake levers 13 and 14 have rotation centers of the reel stands 4 and 5, the brake shoes 2 and 3 and the reel stand 4 so that the braking force does not vary depending on the rotation directions of the reel stands 6 and 7. The angle connecting the contact point 5 and the three pivot points of the brake levers 14 and 15 is set to about 90 °.

In the above structure, at the same time, the motor 9
Is transmitted from the cam gear 6 to the tape pull-out mechanism 13 which is a conventionally known means, and the magnetic tape 12 is pulled out from the cassette (not shown) into the tape pull-out posts 10 and 11.
Slot 1 for loading provided on a substrate (not shown)
It is constructed so as to be pulled out to a predetermined recording / reproducing position along the lines 8 and 19. The change in the rotation resistance of the reel stand in the tape drawing process from the start to the end of this drawing is a straight line C shown in FIG. 8, which is different from the ideal reel stand rotation load curve A shown together.

The ideal reel base rotation load curve A will now be described. Since a large force is required to operate the tape pull-out mechanism 13 composed of a toggle mechanism at the tape pull-out start point, the tape is required. It is preferable that the resistance applied to the pull-out posts 10 and 11, that is, the tape tension of the magnetic tape 12 is small.
In the vicinity of the start of pulling out, the amount of pulling out the magnetic tape 12 per unit rotation angle of the toggle mechanism is small, and therefore,
It is preferable that the rotation resistance applied to the reel bases 4 and 5 is small.

Then, the tape pull-out post 10,
Since the pulling-out force of the tape pulling-out mechanism 13 becomes stronger as 11 moves forward in the loading elongated holes 18, 19, even if the tape tension applied to the pulling-out posts 10, 11 increases, its operation is not hindered. In the vicinity of the end point of the tape pulling stroke, although the moving speed of the tape pulling posts 10 and 11 is set to be gradually decreased and set to stop at the end point, inertia of the tape pulling post 10 and 11 is set. In order to prevent a phenomenon in which the magnetic tape is pulled out faster than the moving speed and the magnetic tape cannot be kept wound around the tape pull-out posts 10 and 11, the reel stands 4 and 5 are separated.
Ideally, the rotational resistance imparted to the tape should be continuously increased and maximized at the end of the tape drawing process.

Compared to the ideal reel base rotation load curve A described above, since the load curve C according to the conventional configuration is constant in the entire tape drawing process, the reel base has a large rotational resistance at the drawing start point, and the tape drawing mechanism. A large force is required for the operation of 13, and the necessary reel stand rotation resistance cannot be obtained at the draw-out end point, which is insufficient to suppress the ejection of the magnetic tape from the cassette.

[0009]

As described above, conventionally,
Since the reel stand braking device is configured so that the rotation resistance of the reel stand is constant during the entire tape pulling process, the tension of the magnetic tape acts as a resistance against the movement of the tape pulling post at the pulling start point, and the tape pulling mechanism operates. Requires a large motor output, and at the end point of the drawer, the rotation resistance of the reel stand necessary to stop the movement of the magnetic tape ejected from the cassette cannot be obtained, and the magnetic tape is originally wound around the tape drawer post. There was a problem of leaving.

[0010]

In order to solve the above-mentioned problems, the reel stand braking device of the present invention is provided with a brake shoe on a sliding lever which slides in conjunction with the operation of a tape pulling mechanism, and The rotation resistance of the reel base continuously changes as the drawing process progresses. According to the present invention, it is possible to impart a continuously changing rotational resistance to the reel base with the operation of pulling out the magnetic tape from the cassette with a simple structure, so that the load of the pulling-out operation of the tape pulling-out mechanism is reduced and the magnetic tape is reduced. The tension can be maintained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is arranged on a substrate at a predetermined interval and has a cylindrical shape centered on each rotation center on the lower surface. A pair of first and second reel bases on which protrusions are formed, and a reversible slide below the reel bases at least between a first position and a second position in a direction connecting the reel bases. A slide lever movably disposed on the substrate, and a protrusion of the first reel stand and the second reel stand as the slide lever moves from the first position to the second position. A brake shoe provided on the sliding lever so as to contact the outer peripheral wall and increase its pressing force continuously, and to move the sliding lever in conjunction with the pulling-out operation of the tape pulling-out mechanism. Drawer of the tape pull-out mechanism Create both reel base braking force increases with the can be performed more appropriately load reduction and the magnetic tape tension holding drawer operation of the tape pull-out mechanism.

(Embodiment) The following is a description of claim 1 of the present invention.
An embodiment of the invention described in 1. will be described with reference to FIGS. 1 to 5. In the plan view of FIG. 1 and an enlarged perspective view of an essential part of FIG. 2, reference numerals 4 and 5 are rotatably arranged on a substrate (not shown) with a predetermined spacing, and each of them is arranged on the lower surface. Cylindrical protrusions 4a, 5a centering on the center of rotation
And 1 is a slide table that reversibly slides between a first position and a second position with a shaft (not shown) located at the center of rotation of the reel tables 4 and 5 as a guide. The sliding lever 1 is integrally formed with brake levers 1a and 1b which elastically deform in the sliding direction of the sliding lever 1 as shown in FIG.

At the tips of the brake levers 1a and 1b, the protrusions 4a and 4a of the reel bases 4 and 5, respectively.
Brake shoe 2, which is set to be able to contact the outer periphery of 5a,
3 are provided. The pin 8 planted on the sliding lever 1 is provided with a cam groove 7 of a cam gear 6 rotated by a motor 9.
, And the sliding lever 1 is configured to reversibly slide with the rotation of the motor 9. As in the conventional configuration, the brake levers 1a and 1b are connected to the rotation centers of the reel bases 4 and 5 and the brake shoes 2 and 3 so that the braking force does not vary depending on the rotation directions of the reel bases 4 and 5. Brake lever 1 and contact points of reel stands 4 and 5
The angle connecting the three points of the rotation centers a and 1b is set to about 90 °.

In the above structure, the rotation of the motor 9 is transmitted via the cam gear 6 to the tape pull-out mechanism 13 which is a conventionally known means such as a toggle mechanism, and the tape pull-out posts 10 and 11 are provided on the substrate. The magnetic tape 12 is pulled out from the cassette (not shown) along the loading slots 18 and 19. FIG. 3 shows changes in the reel base rotation resistance in the tape drawing process from the start to the end of the drawing.

The reel base rotation resistance by the reel base braking device of the present invention is a curve B, and in order to substantially match the ideal reel base rotation load curve A shown together, the sliding lever 1 is used.
This is realized by continuously changing the cam groove 7 of the cam gear 6 that regulates the movement distance of the. That is, the brake levers 1a and 1b are elastically deformed due to the movement amount of the sliding lever 1, and the pressing force thereof is the brake shoe 2 and
3, the rotational resistance of the reel bases 4 and 5 is increased or decreased, and the amount of elastic deformation of the brake levers 1a and 1b increases continuously as the sliding lever 1 moves in the direction of arrow D. The reel stand rotation resistance also increases, and on the contrary, arrow E
The rotation resistance of the reel base continuously decreases as it moves in the direction.

FIG. 4 shows the configuration of the present invention at the tape pull-out starting point. Brake lever 1 of the sliding lever 1
The elastic deformation amounts of a and 1b are small, and the reel base rotation resistance is small. The structure of the present invention at the end point of the tape drawing is shown in FIG. The sliding lever 1 is moved in the most D direction, and the brake lever 1a,
The elastic deformation amount of 1b is maximized and the reel stand rotation resistance is also maximized. As described above, the present invention is configured so that it is possible to obtain an arbitrary reel base rotation resistance simply by operating the shape of the cam groove 7.

[0017]

As described above, according to the present invention, by operating the cam groove shape that determines the elastic deformation amount of the brake lever, the optimum reel stand rotation resistance can be obtained over the entire tape drawing stroke. It is possible to reduce the load of the drawing operation of the drawing mechanism and to maintain the tension of the magnetic recording tape.

[Brief description of the drawings]

FIG. 1 is a plan view of a reel stand braking device according to an embodiment of the present invention.

FIG. 2 is an external perspective view of an essential part of the reel stand braking device according to the embodiment.

FIG. 3 is a diagram showing a change in rotation resistance of the reel stand of the reel stand braking device in the embodiment.

FIG. 4 is a plan view of the essential parts of the reel stand braking device in the same embodiment when the tape pulling out is started.

FIG. 5 is a plan view of the essential parts of the reel stand braking device in the same embodiment in a state where the tape drawing is completed.

FIG. 6 is a plan view of a reel stand braking device in a conventional example.

FIG. 7 is a diagram showing a resistance change in rotation of a reel stand of a reel stand braking device in a conventional example.

FIG. 8 is a diagram showing a relationship between a reel base rotation resistance and a tape drawing process.

[Explanation of symbols]

 1 Sliding Lever 1a, 1b Brake Lever 2, 3 Brake Shoe 4, 5 Reel Stand 4a, 5a Projection 6 Cam Gear 7 Cam Groove 8 Engaging Pin 9 Motor 10, 11 Tape Draw Post 12 Magnetic Recording Tape 13 Tape Draw Mechanism

Claims (1)

[Claims] 1. A pair of first and second reels, which are arranged on a substrate with a predetermined spacing, and on the lower surface of which are formed cylindrical protrusions centering on their respective rotation centers. A table, and a slide lever arranged on the substrate so as to be reversibly slidable between at least a first position and a second position below the reel tables in a direction connecting the reel tables. As the sliding lever moves from the first position to the second position, the sliding lever comes into contact with the outer peripheral walls of the protrusions of the first reel stand and the second reel stand, and the contact portion is continuously pressed. And a brake shoe provided on the sliding lever so that the sliding lever is moved in conjunction with the pulling-out operation of the tape pulling-out mechanism.