JP2005070716A - Braille display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems wherein the expansion and contraction due to the temperature of a wire of a shape memory alloy are utilized directly for appearance and disappearance of a braille pin and therefore there is a need for arranging the wire of the shape memory alloy in the direction coaxial with the braille pin and the dimensions in a height direction increase and also, the need for the holding current for the purpose of continuation of heating arises, in order to hold the state of the elongation or contraction of the wire of the shape memory alloy and the current consumption increases. <P>SOLUTION: The expansion and contraction of the wire of the shape memory alloy are changed to the rotation of a cam, and the braille pin is ejected by the cam, by which the wire of the shape memory alloy can be arranged, in a direction nearly perpendicular to the braille pin, and the height thereof becomes smaller. Further, the state of the appearance of the braille pin can be maintained, without passing the holding current by the shape of the cam or by combining springs to actuate the cam as a toggle and therefore the current consumption can be reduced. The obtained braille display device is a thin type and therefore has advantages, in that the display device can be easily built into another equipment and the electric power consumption of the equipment can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a braille display device used by a visually impaired person using a shape memory alloy.

  Braille display devices that use shape memory alloy wires, coils, rods, etc. that have been proposed in the past patent documents, etc., only use the properties of shape memory alloys, and are easy to use when incorporated into devices. It did not consider the point of miniaturization and energy saving.

  Specifically, in order to simplify the structure, the expansion / contraction direction of the shape memory alloy is set to the same direction as the direction in which the Braille pins come in and out. (For example, see Patent Document 1 to Patent Document 5)

  In addition, the shape memory alloy is expanded and contracted by heating from the outside or energizing, but there is a proposal that the heating or energizing heating must be continued in order to keep the Braille pin in and out, especially in the “out” state. Many. (For example, see Patent Document 2 to Patent Document 5)

An example (see Patent Document 1) in which a mechanism for holding the braille pin in and out is provided (see Patent Document 1).
JP 2001-265213 A Patent No. 2914348 JP-A-11-212446 JP-A-11-184369 JP 2000-112339 A

  As described above, the braille display device using the shape memory alloy proposed in the conventional patent document has a high height because the direction of expansion and contraction of the shape memory alloy is the same as the direction in and out of the braille pin. However, it is desirable that the braille display device be as thin as possible when it is incorporated into a device. Also, in order to keep the braille pin in and out, the current had to be passed to keep the shape memory alloy working, but this was a problem from the viewpoint of energy saving.

  In addition, the above-described mechanism (see Patent Document 1) that holds the state where the Braille pins are brought in and out using a magnetic field requires a strong driving force to resist the adsorption force necessary for holding. There was a problem. In other words, the magnetic attraction force decreases rapidly when a gap is formed on the attracting surface. Therefore, in order to obtain a certain level of restoring force, the magnetic field must be strengthened, and as a result, the attraction force is separated when the braille pin enters and exits. Only a strong driving force is required.

  An object of the present invention is to solve the problems of the conventional configuration, and an object of the present invention is to realize an energy-saving Braille display device that has a low height and does not require a holding current.

  In order to achieve the above object, the first problem solving means of the present invention is to provide a cam that rotates in accordance with the expansion and contraction of the wire of the shape memory alloy and pushes up the braille pin.

    In the second problem solving means, a cam is combined with a spring to cause the cam to perform a toggle operation.

  The operation of the first problem solving means is as follows. When a cam that allows the Braille pin to enter and exit is provided, the direction of installation of the shape memory alloy wire that rotates the cam increases the degree of freedom. In addition, when the Braille pin is in the “out” state, that is, when the Braille pin is pushed out on the cam surface, it will not be retracted even if the Braille pin is pushed with a finger. Will be.

  However, when the center of rotation of the cam is away from the axis of the braille pin, even if the braille pin in the `` out '' state is on the cam surface, when the braille pin is pushed with a finger, a rotational moment acts on the cam, I will not back up because it rotates.

  The second problem solving means solves this. By combining a spring with the cam so that the cam performs a toggle operation, the spring force becomes a resistance force when the braille pin is pushed with a finger and the cam rotates. In addition, even if the braille pin pressed by the finger is once retracted, the cam that tries to return by the force of the spring pushes up the braille pin when the finger is released. Another advantage of having the cam toggle is that if you try to put the braille pin in the “out” state while holding the braille pin with your finger, you can first put the spring in the “out” state Therefore, when the finger is released, the cam rotates by the force of the spring and pushes out the braille pin.

  As described above, according to the present invention, it is possible to provide a braille display device that can be thinned and thus can be easily incorporated into equipment, and realizes energy saving that does not require holding current.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The shape memory alloy wire is described as having a property that it is extended at a normal temperature and returns to its original length and shortens when energized and heated.

  1 and 2, the Braille pin 1, the guide plate 13 having a hole so that the Braille pin 1 can slide up and down, the guide plate 14, the cam 2, the pulley 3 integrated with the cam 2, and one end of the wire fixing portion to the pulley 3. 6, the shape memory alloy wires 4 and 5, the switch 7, the contact 8, the contact 9, and the drive power supply 10, the other ends of which are fixed to the frame 15.

  In FIG. 1, when the switch 7 is tilted to the contact 8 side, the shape memory alloy wire 4 generates heat and shortens its length when energized, so the pulley 3 is rotated clockwise. The cam 2 integrated with the pulley 3 pushes out the braille pin 1 guided by the plate 13 and the plate 14 with holes for guiding the braille pin. Thereafter, even when the energization is stopped and the temperature is lowered and the length of the shape memory alloy wire 3 is extended, the cam 2 is stopped as it is due to shaft friction or the like, so the Braille pin 1 is in the “out” state. It remains. At this time, even if the braille pin 1 is pushed with a finger to read the braille, the cam 2 is supported underneath, so that it is not retracted.

  Next, in FIG. 2, when the switch 7 is tilted to the contact 9 side, the shape memory alloy wire 5 is heated when it is energized and its length is shortened, and the cam 2 integrated with the pulley 3 is moved counterclockwise. Rotate. At this time, since the surface of the cam 2 escapes from the braille pin 1, the braille pin 1 falls by gravity and enters an “entering” state. At that time, even if it does not drop immediately due to the influence of friction or the like, the Braille pin 1 is lightly lowered by the force when it is pushed with a finger to read the Braille. Even when the energization is stopped and the length of the shape memory alloy 4 is extended, the cam 2 is stopped as it is due to shaft friction or the like, and the braille pin 1 once in the “on” state is also left as it is.

  3 and 4 show a configuration in the case where the rotational center position of the cam 2 is not located at a position close to the axis of the Braille pin 1 but is slightly separated for convenience of configuration. In this state, when the braille pin 1 in the “out” state is pressed with a finger, the cam 2 rotates counterclockwise and does not support the braille pin 1 below.

  FIG. 3 shows a state in which the switch 7 is tilted to the contact 8 side. The shape memory alloy wire 4 rotates the cam 2 clockwise, and the cam 2 pushes the braille pin 1. Since one end of the spring 13 is attached to the cam 2 and the other end is attached to the stud 10 of the frame 15, the hook interval at both ends of the spring 13 changes according to the rotation of the cam 2, and the place where the hook interval is the narrowest is shown. At the boundary, the spring 5 performs a so-called toggle operation that works to push the cam 2 upward or downward. In FIG. 3, the braille pin 1 is pushed out by pushing the cam 2 in the direction of arrow A.

  At this time, when the braille pin 1 in the “out” state is pushed with a finger, the cam 2 is rotated, but the spring 13 gives a restoring force to the cam 2 by designing the cam 2 so as not to exceed the neutral point. When the finger is released, the braille pin 1 returns to the “out” state. The finger pressing the braille pin 1 can feel the restoring force of the spring 13 at the fingertip and read that the braille pin 1 is in the “out” state.

  From this, the operation when the cam 2 is driven from the “in” to “out” state when the braille pin 1 is pressed by the finger 15 can also be explained. When the cam 2 is driven and the neutral point is exceeded, the force of the spring 13 works to push up the braille pin 1, so it is clear that the braille pin 1 is in the “out” state when the finger is released.

  As described above, even when the rotation center position of the cam 2 is away from the axis of the Braille pin 1, it is possible to maintain the "out" state of the Braille pin 1 by adding only one spring 13. In addition, the braille pin 1 can be switched in and out even while the braille pin 1 is pressed with a finger.

  FIG. 4 shows a state in which the switch 7 is tilted to the contact 9 side. When the shape memory alloy wire 5 rotates the cam 2 counterclockwise, the cam surface of the cam 2 moves away from the braille pin 1, so that the braille pin 1 falls by gravity and enters an "entering" state. Since the spring 13 applies a force to rotate the cam 2 in the direction of arrow B, the rotation is stopped by the stopper 14.

  As described above, according to the present embodiment, a Braille display device with a small thickness and low power consumption can be obtained by the present invention.

The figure which shows the structure which provided the cam of this invention, and the operation | movement which pushes out a braille pin Diagram showing the operation to retract the same braille pin The figure which shows the operation | movement which pushes out a braille pin by the structure which provided the cam and spring of this invention. Diagram showing the operation to retract the same braille pin

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Braille pin 2 Cam 3 Pulley 4, 5 Shape memory alloy wire 6 Wire fixing part 7 Switch 8, 9 Contact 10 Power supply 11, 12 Braille pin guide plate 13 Spring 14 Stopper

Claims (2)

  A display device that displays Braille pins by entering and exiting Braille pins from a surface that displays Braille, and includes Braille pins, a shape memory alloy wire member, and a cam. A braille display device, wherein the cam is rotated by utilizing any one of the contracted states and the braille pin is pushed out by the cam.   2. The braille display device according to claim 1, wherein a spring is combined with the cam so that the cam is toggled by the force of the spring when the cam rotates.

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