JPH0620340A - Brake driving mechanism of reel turn table - Google Patents

Abstract

PURPOSE:To enable a brake action with fast responsiveness by constituting a brake lever of an operating member for energizing the brake lever in the direction of operating the brake on a reel turn table and a shape memory material which is deformed in shape to a memory shape by heating. CONSTITUTION:The shape memory material 7 is heated and shrinks to its intrinsic memory shape by passing a current to the shape memory material 7. The brake lever 3 is turned clockwise around a fulcrum shaft 4 against the spring force of a spring member 6 by the shrinkage of the shape memory material 7. A pawl part 5 is then disengaged from a tooth part 2 of the reel turn table 1 to attain the state of releasing the application of the brake on the reel turn table 1. The shape memory material 7 is cooled and is deformed in the shape in an elongating direction by shutting off the energization to the shape memory material 7. The brake lever 3 is, therefore, engaged again with the tooth part 2 of the reel turn table 1 by the spring force of the spring member 6, by which the state of operating the brake on the reel turn table 1 is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake drive mechanism for a reel base in a magnetic recording / reproducing apparatus, for example, a tape recorder such as a video tape recorder (VTR).

[0002]

2. Description of the Related Art Conventionally, a reel base brake drive mechanism in a tape recorder has been configured to brake the reel base with a driving force from a motor or a solenoid intervening a brake member such as a cam or an arm member.

[0003]

However, in the conventional brake drive mechanism described above, the brake member and the motor or solenoid as the drive source are often separated from each other structurally. There is a problem in that a large space is required for the parts that transmit the driving force to the brake member, and a large number of parts are required. Further, the solenoid is structurally thick in thickness and heavy in weight, which has been a bottleneck in reducing the thickness and weight of the entire apparatus.

The present invention has been made in order to solve the above-mentioned problems, and makes it possible to greatly reduce the number of parts by eliminating the need for a transmission member between a drive source and a brake member, and to operate it. An object of the present invention is to obtain a brake drive mechanism for a reel stand with a quick response.

[0005]

In order to achieve the above object, a reel base brake drive mechanism according to the present invention comprises a brake lever for controlling the reel base to be in a brake state / a brake release state, and a brake lever for the reel base. It is composed of an operation member for urging in the brake operation direction and a brake release member made of a shape memory material that deforms into a memory shape by heating.

[0006]

According to the brake drive mechanism for the reel stand of the present invention having the above-described structure, the braking state of the reel stand is as follows.
The brake lever is biased toward the reel base by the operation member, and the reel base is in the brake state.

To release the brake of the reel base, when the shape memory material is energized and the shape memory material heats and contracts, the brake lever rotates in a direction away from the reel base, and the brake of the reel base is released. It is released.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of the brake drive mechanism of this example. In FIG. 1, reference numeral 1 indicates a reel stand of a tape recorder, and a tooth portion 2 is formed on the peripheral surface of the reel stand 1.
Reference numeral 3 is a brake lever for controlling the reel base 1 to be in a brake operation state and a brake operation release state. The brake lever 3 swings around a fulcrum shaft 4, and a claw portion 5 provided at the tip of the brake lever 3 has the above-mentioned reel. It engages with the tooth portion 2 of the base 1 (brake operation state) and disengages (brake operation release state). Further, normally, the brake lever 3 is biased toward the reel base 1 side by the spring force of the spring member 6, and the claw portion 5 engages with the tooth portion 2 of the reel base 1 to bring the reel base 1 into a braking operation state. ing.

On the other hand, a shape memory material 7 made of a wire material serving as a brake releasing member is arranged on the side opposite to the reel base 1 of the brake lever 3 described above, and the tip end of the shape memory material 7 is a fulcrum shaft 4 of the brake lever 3. Pin 8 provided closer to the claw portion 5 side
It is fixed to. The power source 9 and the switch 10 are connected to the terminals of the shape memory material 7. This shape memory material 7
Is made of, for example, a nickel-titanium (NiTi) alloy, and has the property of returning to the original shape memorized when an electric current flows through the shape memory material 7 and is heated to a predetermined temperature. The action of shortening and shortening the length of 7 is utilized, and the temperature characteristics of the shape memory material 7 are shown in FIG.

Next, the operation of the brake drive mechanism constructed as described above will be described with reference to FIGS. Reel stand brake operating state Since no current is applied to the shape memory material 7,
As shown in FIG. 1, the shape memory material 7 is in an expanded state, so that the brake lever 3 is urged toward the reel base 1 by the spring force of the spring member 6, and the claw portion 5 is engaged with the tooth portion 2 of the reel base 1. Accordingly, the reel base 1 is in the brake operating state.

Reel base brake release operation from reel base brake operating state By supplying a current to the shape memory material 7, the shape memory material 7 is heated and contracts to the original memory shape. The contraction of the shape memory material 7 causes the brake lever 3 to rotate clockwise against the spring force of the spring member 6 with the fulcrum shaft 4 as a fulcrum, and the pawl portion 5 causes the teeth of the reel base 1 to move as shown in FIG. The brake is released from the portion 2 and the reel base 1 enters the brake release operation state.

From the reel stand brake released state to the reel stand brake operating state By cutting off the power supply to the shape memory material 7, the shape memory material 7 is cooled and changes its shape in the extending direction. Therefore, the brake lever 3 is rotated again toward the reel base 1 by the spring force of the spring member 6, and the claw portion 5 engages with the tooth portion 2 of the reel base 1 as shown in FIG. It becomes an operating state.

As described above, the reel base brake drive mechanism utilizes the shape change that expands and contracts due to the heating action of the shape memory material 7, and operates the brake lever 3 to bring the reel base 1 into the brake operating state and the brake releasing state. Since the brake control can be performed and the brake lever 3 can be directly driven by the shape memory material 7 serving as a drive source, the number of parts can be significantly reduced, and accordingly, as in the conventional case. There is an advantage that a large space is not required for the driving force transmission component and the responsiveness of the brake control operation can be accelerated.

FIG. 3 shows another embodiment of the above-mentioned brake drive mechanism. In the case of this example, the brake lever 3 swinging around the fulcrum shaft 4 is rotated in the brake releasing direction with respect to the reel base 1 by the contraction action of the shape memory material 7 due to heating. However, in the case of this example, the toggle spring 11 is used instead of the spring member 6 used in FIG. The toggle spring 11 has a support shaft 1 whose middle portion and one end portion protrude from a chassis (not shown).
2 and a pin 13, and the other end of the toggle spring 11 is hooked on a pin 14 protruding from the brake lever 3.

The spring action of the toggle spring 11 formed in this way acts in the brake releasing direction in which the brake lever 3 is urged toward the reel stand 1 side in the braking operation state of FIG. In the rotating operation, the toggle spring 11 reverses the spring biasing direction beyond its dead point, and acts to bias the brake lever 3 in the direction away from the reel base 1. Reference numeral 15 is an operation lever for rotating the brake lever 3 toward the reel stand 1 by a drive source (not shown).

In the state shown in FIG. 3, the above-mentioned brake drive mechanism urges the brake lever 3 toward the reel base 1 side by the spring force of the toggle spring 11 to bring the reel base 1 into the brake operating state. From this brake operating state, a current is instantaneously applied to the shape memory material 7, the shape memory material 7 is contracted and deformed by heating, and the brake lever 3 is rotated by a predetermined angle in a direction away from the reel stand 1, whereby the toggle spring is rotated. 11
Exceeds the dead point and the spring bias direction reverses,
The brake lever 3 is urged to rotate away from the reel base 1, whereby the claw portion 5 of the brake lever 3 is disengaged from the tooth portion 2 of the reel base 1 and the reel base 1 is released from the brake. Further, in this case, the brake operation state of the reel base 1 is such that the claw portion 5 of the brake lever 3 is moved to the reel base 1 by rotating the brake lever 3 to the reel base 1 side by the operation lever 15 by a drive source (not shown). The reel base 1 can be brought into a brake operating state by engaging with the tooth portion 2.

The brake drive mechanism that operates in this way is
A current is momentarily applied to the shape memory material 7 to rotate the brake lever 3 slightly in the reel stand release direction. Then, the spring force of the toggle spring 11 causes the reel stand 1 to be released from the brake. Therefore, the amount of current supplied to the shape memory material 7 can be reduced, and power can be saved.

The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention. For example, as for the brake mechanism of the reel base 1 by the brake lever 3, the method of engaging the tooth portion 2 of the reel base 1 with the claw portion 5 of the brake lever 3 has been described. A method of contacting the pad provided in 3 may be used. In addition, although the case where the shape memory material 7 is a metal material has been described in the other embodiments, it is also possible to use a synthetic resin material other than the metal material and to deform the shape due to a thermal effect applied thereto. Further, the brake driving mechanism of the reel stand according to the present invention is not limited to a tape recorder such as a video tape recorder (VRT), but can be widely applied to a reel stand of a recording / reproducing apparatus.

[0019]

As described above, the reel base brake drive mechanism according to the present invention utilizes the shape deformation that expands and contracts due to the heating action of the shape memory material, and operates the brake lever to bring the reel base into the brake state and the brake release state. Since the brake control can be performed in the state, the number of parts can be significantly reduced, and a large space can not be taken for the driving force transmitting parts as in the conventional case.

In addition, a brake as a drive source of a brake drive mechanism that has been conventionally used has the advantage of being able to perform a brake operation with a quick operation response, and since no magnet is used at all, a reel stand on It does not adversely affect the magnetic tape.

[Brief description of drawings]

FIG. 1 is a schematic view of a brake drive mechanism in this example.

FIG. 2 is a temperature characteristic diagram of a shape memory material.

FIG. 3 is a schematic view of the brake release state of FIG.

FIG. 4 is a schematic diagram of another example of a brake drive mechanism.

[Explanation of symbols]

 1 reel stand 2 teeth part 3 brake lever 4 fulcrum shaft 5 claw part 6 spring member 7 shape memory material 9 power supply 11 toggle spring 12 support shaft 14 pin 15 operation lever

Claims (2)

[Claims] 1. A brake lever for controlling the reel stand to a brake state / brake release state, an operating member for urging the brake lever in the reel stand brake operation direction, and a shape memory for deforming the shape into a memorized shape by heating. A brake drive mechanism for a reel stand, comprising a brake release member made of a material. 2. The reel stand according to claim 1, further comprising a toggle spring member for urging the brake lever in a reel stand brake operation direction and a reel stand brake release direction in accordance with a rotation angle thereof. Brake drive mechanism.