JPS60157521A - Braking device for rotor - Google Patents

Abstract

PURPOSE:To obtain high braking effect with a simple structure, by providing rotatably a brake arm made of an elastic material, in the midst of which a U- shaped part is formed, in a brake of a rotor such as a reel stand of a magnetic recording reproducer. CONSTITUTION:Brake arms 9 made of synthetic resin material having appropriate elasticity respectively are arranged against a supply reel stand 2 and a winding reel stand 3 in a video cassette tape recorder. Each of the brake arms 9 is formed by providing a U-shaped part 9a, which is in about a U-shaped state, on a side on a confronting side of an L-shaped reel stand, brake pads 6 are stuck to parts abutting against each of the reel stands 2, 3 and both the arms 9 are energized in a braking direction by a main brake spring unit 11. The titled brake is so constituted that a braking state can be released by making a brake releasing arm 10 arranged against the other end parts of the respective brake arms 9 overlapping with each other actuate in the B direction against a spring 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a braking device for a rotating body that brakes the rotation of a reel stand of a magnetic recording/reproducing device such as a video cassette tape recorder. Background] FIG. 1 shows an explanatory view of magnetic tape transport in a video cassette tape recorder, etc., in which 1 is a magnetic tape, 2 is a supply reel stand, and 3 is a take-up reel stand.

The magnetic tape 1a stored in the cassette half 1 is transferred to the supply reel stand 2 or take-up reel stand 3 in the direction of arrow R and F in FIG. 1 via a drive system (not shown). When stopping the supply reel 2 and take-up hv
The rotation of the reel stand must be stopped. Rapidly transporting the magnetic tape 1a by the supply reel stand 2 in the direction of the arrow in FIG. 1 is generally called "rewinding", and rapidly transporting it in the direction of arrow F is called "fast forward". When changing from the "fast forward" state to the stopped state, the inertia of the magnetic tape 1a, the supply reel stand 2, and the winding IJ
- Since the inertia of the magnetic tape 1a becomes very large, various measures have been taken to prevent excessive loads from being applied to the magnetic tape 1a when stopping the magnetic tape 1a.

FIG. 2 shows a plan view of a conventional braking device for a rotary body in a stopped state. 4 is a main brake arm in which an approximately 5-shaped corner 11 is rotatably supported on a rotation shaft 8; It has a sub brake arm 5 rotatably supported by the main brake arm 5, and a sub brake arm spring body 12 is suspended between the sub brake arm 5 and the main brake arm 4. Further, the sub brake arm 5 is attached to one side of the L-shape facing the supply reel stand 2 and the take-up reel stand 6, respectively, and rotation regulation by the sub brake arm 5 is performed at the locking portion of the sub brake arm 5. 5a comes into contact with the main brake 7-me 4.

The auxiliary brake arm 5 has a brake pad 6 that comes into contact with a rotating body for braking using frictional resistance, that is, a supply reel stand 2 and a take-up reel stand 6. A raw brake arm spring body 11 is attached between the other sides of the main brake arm 4 and is biased so as to rotate the other side of the figure 5 shape inward. Although FIG. 2 is a diagram showing a stopped state, when operating the equipment, the sub brake arm 5 is released via the main brake arm 4 by moving the brake release arm 10 in the direction of arrow B against the tension of the spring 15. As a result, the supply reel stand 2, take-up reel stand 3, and brake pad 6 are separated from each other.

The conventional braking device is constructed as described above and has the following functions. As an example, a case will be described in which the rewinding state is stopped.

As mentioned above, when the equipment is in operation, the brake pads 6 are separated from the rotating body, but when the equipment is stopped, the brake release arm 10 rotates, so that the brake pads 6 of the sub-brake arm 45 are separated from the supply reel stand 2, Take-up) Abuts on reel stand 3.

At this time, each reel stand rotating in the direction of the broken line arrow C in FIG. 2 is braked. First, the supply reel stand 2
Considering the braking state on the side of When they come into contact, braking force is applied. The state of the main brake arm 4 at this time is generally a so-called relief state, and the braking force is not very strong.

On the other hand, considering the braking state on the take-up reel stand 3 side, firstly, the main brake arm 4 is braked by the tension of the main brake arm spring body 11 with the rotation shaft 8 as a fulcrum. Second, the auxiliary brake arm 5, which rotates integrally with the main brake arm 4, connects a line connecting the center of the take-up reel table 3 and the contact center of the brake pad 6, and the contact center of the brake pad 6 and the contact center of the brake pad 6. By appropriately selecting the angle θ formed with the line connecting the centers of the rotating shaft 8, a generally so-called automatic biting state is achieved. Therefore, the braking force in this state, which is unrelated to the tension of the main brake arm springing body 11, is exerted by the tension of the secondary brake arm springing body 12 using the pin 7 as a fulcrum, and the braking force is very strong, but it is a secondary brake force. By appropriately selecting the tension of the brake arm spring 12, a stable braking force can be obtained. That is, when stopping from the rewinding state, the braking state on the supply reel 2 side is in the "escape" state, and the braking state on the take-up reel 3 side is in the "biting" state, and the sub-brake arm springing body 12 is very stable. Therefore, the magnetic tape 2 is not subject to any slack or abnormal load.

In addition, in the case of fast forwarding or stopping, the same process is performed conversely on the supply reel stand.

As described above, it is very suitable as a braking device, but it requires the sub-brake arm 5, the sub-brake spring body 12, pin 7, etc., and has the drawback that it has many parts, is structurally complex, and costs are high.

[Purpose of the invention]

The present invention was made in view of the above-mentioned situation, and an object of the present invention is to provide a braking device for a rotating body that can simplify the structure and reduce the number of parts.

[Summary of the invention]

The braking device for a rotating body of the present invention may be formed such that the brake arm is attached to a rotary shaft so as to be rotated around a rotation axis to brake the rotating body, or the brake arm may be formed of a multi-layered elastic material. At the same time, one side of the brake arm on the side facing the rotating body is formed into a U-shaped portion, with one side being in contact with the rotating body and the other side being the side to which the rotating shaft of the brake arm is attached.

[Embodiments of the invention]

Hereinafter, an embodiment of the braking device for a rotary body according to the present invention will be described with reference to FIG. 3, where the same parts as those in the conventional system are denoted by the same reference numerals, and explanations of the same parts will be omitted. FIG. 6 shows the stopped state, and a brake arm 9 made of synthetic resin or a material having substantially the same elasticity as the synthetic resin is disposed facing the supply reel stand 2 and take-up reel stand 3. Brake arm 9 has
A substantially U-shaped portion 9a is provided on one side of the L-shaped reel stand opposite to the rotating body, and the other side is the brake arm body side. A deflection regulating portion 9b is provided for regulating deflection on the side that contacts the rotating body. And supply reel stand 2
, winding) A brake butt 6 is fixed to a brake arm 9 by an appropriate method on the part of the reel stand 5 that comes into contact with the rotating body,
A main brake spring body 11 is suspended between one side of the two brake arms 9 opposite to the side facing the reel stand.

Taking as an example the case where this braking device is stopped from the rewinding state, when the brake release arm 100B is stopped, the biasing force in the arrow direction of the brake release arm 100B is released, the brake arm 9 rotates, and the brake pad 6 contact the supply reel stand and the take-up reel stand 3, respectively. At this time, each reel stand rotating in the direction of the dashed arrow C in FIG. The brake arm 9 is rotated about the rotation axis q as a fulcrum, and the brake pad 6 comes into contact with the supply reel stand 2 to apply a braking force.

At this time, the brake arm 9 is in a "relief" state, and the braking force is not very strong.

Next, considering the braking condition on the take-up reel table 6 side, the first
The brake arm 9 is braked by the spring force of the main brake arm spring 11 with the rotation shaft 8 as a fulcrum. However, by appropriately selecting θ in FIG. 3, the brake arm 9 becomes automatically wedged in, so it is unrelated to the tension of the main brake arm spring 11. In this state, the braking force is U-shaped. U-shaped portion 9a due to the elastic force of shaped portion 9a
Acts as a fulcrum near the center of curvature.

Although the braking force is strong, the width of the U-shaped portion 9a,
By appropriately selecting the thickness, stable braking force can be obtained. In order to prevent the U-shaped portion 9a from becoming so-called sagging (a state in which the elastic limit is exceeded), the deflection regulating portion 9b is arranged with an appropriate gap K within the elastic deformation range of the U-shaped portion 9a. As a result, a highly durable braking device can be obtained.

It goes without saying that the same applies when stopping from the fast forward state. Furthermore, it is clear that if the brake arm 9 is not provided with the U-shaped portion 9a, an abnormal biting state will occur when braking is applied suddenly, resulting in an extremely unstable braking state. It is generally known. That is, the U-shaped portion 9a functions as a conventional sub brake arm spring body 120.

As described above, in the braking device for a rotating body according to the present embodiment, an L-shaped brake arm made of an elastic material such as resin is rotatably supported at substantially the corner portion, and one side in contact with the rotating body is supported on one side. Since the U-shaped part is configured such that one side is in contact with the rotating body and the other side is the brake arm main body side, the rotating body can be elastically braked. Eliminating the need for pins reduces the number of parts, simplifies the structure, and improves economic efficiency.

The above embodiment described the case of braking the reel stand, but
Similar effects can be obtained when braking other rotating bodies.

〔Effect of the invention〕

As described above, the braking device for a rotating body of the present invention has the advantage of being able to reduce the number of parts and simplifying the structure.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of magnetic tape transfer in a general cassette, Fig. 2 is a plan view of a conventional reel stand braking device when the reel stand is stopped, and Fig. 3 is an embodiment of the rotary body braking device of the present invention. FIG. 3 is a plan view of the rotating body in a stopped state. 1a... Magnetic tape, 2... Supply reel stand, 6...
・Take-up reel stand, 9...brake arm, 9...
・U-shaped part, 10...Brake release arm, 11
・Main brake arm spring body. ke/Figure 72

Claims (1)

[Scope of Claims] t. A braking device for braking a rotating body in which a brake arm is attached to be rotated about a rotation axis, the brake arm being formed of an elastic material,
A braking device for a rotating body, characterized in that one side of the brake arm facing the rotating body is formed into a U-shaped portion, with one side being in contact with the rotating body and the other side being a side on which the rotating shaft of the brake arm is attached. Z: Between the supply reel stand and the take-up reel stand provided in the magnetic recording/reproducing device, one side of an approximately L-shape facing the reel stand is located in the escape direction and the other in the automatic bite direction with respect to the reel stand. The two arranged brake arms and the other side of the brake arm are rotated inwardly to urge the other side opposite to the reel stand to approach the reel stand. a main brake arm spring body,
A brake release arm is provided which is formed to resist the tension of the main brake arm spring and rotate one side of the above-mentioned shape on the side where the main brake arm spring is mounted outward to release the brake. A braking device for a rotating body according to claim 1.