JP3332547B2 - Reflective overhead projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective overhead projector.

[0002]

2. Description of the Related Art Overhead projectors, which illuminate a document in which characters, figures, and the like are recorded on a transparent sheet and project the image of the document on a screen in an enlarged manner, are widely and generally used in various meetings and presentations. . Such overhead projectors are classified into two types, a reflection type and a transmission type, according to the difference in the illumination method of the original. For the reflective type, the light source for illuminating the original is built into the projection head,
The original is illuminated from below by a reflected light from a mirror Fresnel plate provided on the stage, and is projected via a projection lens and a projection mirror provided in a projection head unit. In the transmission type, a light source for illuminating the document is provided on the lower surface side of the stage, the document is irradiated from the lower surface side through a Fresnel lens provided on the stage, and is also projected via a projection lens and a projection mirror.

[0003] Of these, in particular, in the reflective overhead projector, the light source is located above the mirror Fresnel plate, so that the light source is located below the mirror Fresnel plate compared to the transmissive overhead projector where the light source is located below the mirror Fresnel plate. It is possible to reduce the thickness of
It is easy to reduce the size and weight of the overhead projector. For this reason, most portable overhead projectors are reflection-type overhead projectors that employ a reflection-type illumination method for a document.

[0004] By the way, in order to make the overhead projector easy to carry, it is natural that the overhead projector is lightened,
In addition, the external dimensions must be reduced, especially the thickness must be as small as possible. For this reason, in a reflective overhead projector, since there are no components such as a light source below the mirror Fresnel plate, the projection head unit is placed in a retracted state in which the arm holding the projection head unit is folded down. It is stored in the dead space at the bottom of the box, achieving small size and light weight during storage.

For example, 1991 Utility Model Application Publication No. 69
In No. 04, one end of a mirror Fresnel plate is rotatably mounted on a stage, and when the overhead projector is used, the mirror Fresnel plate is held horizontally by a locking device, and when the arm is stored with the arm folded down, this lock is used. Release the holding by the stopper and rotate the mirror Fresnel plate to the bottom,
A method for storing the projection head unit in the space created by this is disclosed.

[0006]

However, in the above-described method, when the overhead projector is used, the mirror Fresnel plate is supported horizontally at one point by a locking member in addition to the shaft attachment portion. Therefore, for example, when a pen or the like adds or corrects a document placed on the stage, the mirror Fresnel plate is deflected by pressing, making it very difficult to write. Also, at this time, a pen, a pointing stick, or the like may be caught in a gap created between the bent mirror Fresnel plate and the main body of the overhead projector, or may fall below the mirror Fresnel plate.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art. In a reflection type overhead projector in which the mirror Fresnel plate can be rotated, the mirror Fresnel plate is used when the mirror Fresnel plate is held horizontally. It is an object of the present invention to provide a reflection type overhead projector which does not bend or rotate downward even when it is pressed from above.

[0008]

In order to achieve the above object, a reflection type overhead projector according to the present invention is provided.
Projector book with one end of mirror Fresnel plate attached
Holds the body and the projection head with projection optics at one end
And the other end of the arm is a mirror.
-The professional center of rotation of the Fresnel plate
Attached to the ejector body and the arm
When the arm is standing, the slide that is linked to the
The mirror fresnel plate is turned to the horizontal position by the lever.
When the arm falls down, the mirror Fresnel
Rotate the plate into the projector body, and
Is stored inside the projector body,
A mirror Fresnel plate attached to the projector body
Supports the mirror Fresnel plate in the horizontal position on the lower surface on the other end side of the
A supporting member for slidably mounting the arm
In conjunction with the slide of the slide lever when standing up,
Place the support member in the direction opposite to the center of rotation of the mirror Fresnel plate
And slide the tip inside the projector body.
Wall of the portion different from the rotation center side of the mirror Fresnel plate
By inserting the mirror into the recess provided on the surface,
This is to hold the Renel plate in a horizontal position.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part showing a lock mechanism of a mirror Fresnel plate in a reflection type overhead projector embodying the present invention. FIG. 2 is an external perspective view of the reflective overhead projector according to the present invention in use. A stage 4 composed of a Fresnel mirror 3 is provided on the upper surface of the pedestal 2 of the reflection type overhead projector 1, and a document 5 having an image recorded on a transparent sheet is placed thereon. At both ends of the pedestal portion 2, upper covers 6a and 6b are pivotally mounted, respectively, to cover the upper portion of the stage 4 when the reflection type overhead projector 1 is stored, so that the stage 4 can be easily carried.

A support arm 7 composed of two arms is rotatably mounted on a main shaft 13 to be described later on the pedestal portion 2, and a projection head portion is provided on the distal end side (free end side) of the support arm 7. 8 is rotatably mounted on the shaft. A projection lens 9 is incorporated in the projection head unit 8, and a projection mirror 11 is pivotally mounted on the upper surface along the projection head unit 8 so as to be foldable. When the switch is turned on, a light source built in the projection head unit 8 is turned on, and illumination light is given to the stage 4. The illuminating light passes through the document 5 and is reflected by the Fresnel mirror 3, and the image of the document 5 is projected on a screen via the projection lens 9 and the projection mirror 11.

The projection head 8 rotates in the same direction as the support arm 7 in conjunction with the operation of raising and lowering the support arm 7. For example, when the support arm 7 is turned clockwise from the illustrated use position to fall down, the projection head unit 8 is also turned clockwise, and when the support arm 7 is The mirror 3 rotates inside the pedestal portion 2 around the left end shaft attaching portion 3a, and together with this, the projection head portion 8
Is also stored inside the pedestal portion 2 so as to overlap the Fresnel mirror 3 with the upper surface facing down. Conversely, the support arm 2
Is raised from the storage position, the projection head 8 also rotates counterclockwise, and when the support arm 7 has been raised to the illustrated use position, the projection head 8 also comes to the illustrated position.

A shaft attachment portion 7a provided integrally with the lower portion of the support arm 7 is provided with a main shaft 12 provided at the left end inside the pedestal portion 2.
Is rotatably mounted on the shaft. One end of an interlocking lever 14 of the lock mechanism 13 is mounted on the protruding piece 7b provided integrally with the shaft mounting portion 7a. An L-shaped washer 15 is fixed to the pedestal 2. Further, a cam 16 and an interlock gear 17 are rotatably mounted on the washer 15, respectively, and a pin 18 is fixed thereto.

A projection 14 is provided near the center of the interlocking lever 14.
a is provided integrally, and the interlocking lever 14 is urged rightward by a spring 19 provided between the pin 18 and the projection 14a. A sliding groove 14b is provided at the other end of the interlocking lever 14, and a protrusion 16 protruding from the cam 16 is provided.
a is slidably engaged with a.

A portion around the cam 16 is provided with a tooth portion 16b, which meshes with the interlocking gear 17. Further, the interlocking gear 17 is integrally provided with an L-shaped rotating rod 17a. The pivot rod 17a is in contact with and engaged with one end of a lock rod 21 slidably held by a support gutter 4a provided integrally on the back surface of the stage 4.

A protrusion 21a is provided near the center of the lock rod 21.
Are provided integrally. The lock rod 21 is
It is urged to the left by a spring 22 provided between 1a and a projection 4b projecting from the back surface of the stage 4.

Further, at the right end of the lock rod 21, a tapered fitting portion 21b is formed. When the lock bar 21 slides rightward against the bias of the spring 22, the fitting portion 21b fits into the fitting groove 2a provided in the inner left wall of the pedestal portion 2. Thereby, the Fresnel mirror 3
Lock rod 21 so that it does not bend even when pressed from the top.
The Fresnel mirror 3 is horizontally supported on the entire upper surface of the.

The operation of the above configuration will be described. In order to use the reflective overhead projector 1 from the housed state as shown in FIG. 3, first, the upper cover 6b is opened in the direction of arrow A in the figure. Then, the exposed arm 7 is rotated counterclockwise so as to be slowly pulled up. Then, the projection head 8 also rotates counterclockwise in conjunction with the rotation of the arm 7. Further, the spring 23 provided at the end of the Fresnel mirror 3 causes the Fresnel mirror 3 that has entered the inside of the pedestal portion 2 to rotate upward about the shaft attachment portion 3a.

With the rotation of the arm 7, the shaft attachment portion 7 of the arm 7
a also rotates, and accordingly, the projecting piece 7b also rotates counterclockwise. By the rotation of the projecting piece 7b, the interlocking lever 14 is pushed rightward, and the projection 1 engaged with the sliding groove 14b is formed.
By the rotation of the counterclockwise 6a, the cam 16 rotates upward and stands up. At this time, by the bias of the spring 19,
The arm 7 can be rotated with a small force.

When the cam 16 rotates upward, the teeth 16b
The interlocking gear 17 meshing with rotates in the clockwise direction. Then, the rotating rod 17 a provided integrally with the interlocking gear 17 also rotates clockwise, and the lock rod 2 is pressed against the bias of the spring 22.
Slide 1 to the right.

When the arm 7 is completely rotated to the use position shown in FIG. 4, the projection head 8 is also rotated half a turn, and the projection mirror 11 is set in a horizontal state in which it is positioned above. At the same time, the fitting portion 2 of the lock rod 21 slid rightward.
1b is fitted into the fitting groove 2a of the left wall of the pedestal portion 2. As a result, the Fresnel mirror 3 is horizontally supported on the entire upper surface of the lock bar 21, and does not bend or rotate downward even if the Fresnel mirror 3 is pressed.

Thereafter, when the main switch is turned on and the original 5 is placed on the stage 4, a clear enlarged image of the original 5 is projected on the screen. In addition, even if the original 5 is modified by a pen or the like during use, the Fresnel mirror 3 is stably held horizontally without bending as described above.

When the folding operation is performed by rotating the arm 7 clockwise after the use of the reflection type overhead projector 1, the lock mechanism 13 performs an operation reverse to that at the time of setting to the use position described above. At the same time as the rotation rod 17a rotates counterclockwise, the lock rod 21 slides leftward by the bias of the spring 22. Thereby, the fitting portion 21b
Is pulled out from the fitting groove 2a, and the locked state is released. When the arm 7 is lowered, the projection head 8 rotates so that the projection mirror 11 faces downward, contrary to the state in use.

When the arm 7 is further rotated, the corner of the projection head 8 and the projection mirror 11 come into contact with the upper surface of the Fresnel mirror 3, and the Fresnel mirror 3 is rotated inside the pedestal 2. Thereby, in the housed state, the projection head unit 8 is housed inside the pedestal unit 2 together with the Fresnel mirror 3, and the reflection type overhead projector 1 becomes compact.

The lock mechanism of the Fresnel mirror does not operate by mechanical engagement as in the above-described embodiment, but operates an electromagnetic magnet (solenoid) or the like in conjunction with the rotation of the arm, for example. Thus, the locking member of the Fresnel mirror may be operated.

In the overhead projector of the above-described embodiment, the projection head rotates in the same direction as the rotation of the arm, but the projection head rotates in the direction opposite to the operation of rotating the arm. Of course, the present invention can similarly be applied to an overhead projector of a type that rotates in conjunction with it. Further, the Fresnel mirror is configured to rotate into the pedestal portion by pressing the projection head portion. Of course, this can also be rotated into the pedestal portion in conjunction with the rotation operation of the arm. Good.

[0026]

As described above , according to the reflective overhead projector of the present invention, the projector head
A mirror fresnel plate attached to the body
A support member for supporting the Raffle panel in a horizontal position
The arm is slidable and slides when the arm is raised.
The support member is moved to the mirror in conjunction with the slide of the bar.
Slide in the direction opposite to the center of rotation of the Fresnel plate,
The tip of the mirror frame inside the projector body
In a recess provided on a wall surface different from the rotation center side of the
By inserting the mirror Fresnel plate into the horizontal position
Because I was holding it, I needed to raise the arm
The mirror Fresnel plate can be set to the horizontal position simply by performing
In addition to being able to be held, even if the mirror Fresnel plate is pressed from above, it does not bend or rotate downward. Therefore, it is possible to stably modify the original with a pen or the like while using the reflective overhead projector.

Further, it is possible to prevent a pen, a pointing stick or the like from being caught in a gap created between the mirror Fresnel plate and the main body of the overhead projector or falling below the mirror Fresnel plate.

[Brief description of the drawings]

FIG. 1 is a perspective view of a principal part showing a lock mechanism of a mirror Fresnel plate in a reflection type overhead projector embodying the present invention.

FIG. 2 is an external perspective view of a reflective overhead projector embodying the present invention in use.

FIG. 3 is an explanatory diagram of a reflection type overhead projector embodying the present invention in a housed state.

FIG. 4 is an explanatory diagram in a use state of a reflective overhead projector embodying the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reflective overhead projector 2 Pedestal part 3 Fresnel lens 4 Stage 7 Arm 8 Projection head 13 Lock mechanism 14 Interlocking lever 16 Cam 17 Interlocking gear 21 Lock bar

Claims (1)

(57) [Claims] A mirror having a mirror Fresnel plate on which one end is axially mounted.
The projector body and the projection head with the projection optical system
And an arm held at one end.
Of the mirror Fresnel plate on the rotation center side, and
When pivotally attached to the projector body
In both cases, when the arm is standing, it is linked to the standing motion of the arm.
The mirror fresnel plate is moved horizontally by the slide lever
Position, and when the arm falls down, the mirror
-Rotate the Fresnel plate inside the projector
The projection head is stored inside the projector body.
In a projection type overhead projector, a mirror Fresnel plate which is axially attached to the projector body
Supports the mirror Fresnel plate in the horizontal position on the lower surface on the other end side of the
A supporting member for slidably mounting the arm
In conjunction with the slide of the slide lever when standing up,
Place the support member in the direction opposite to the center of rotation of the mirror Fresnel plate
And slide the tip inside the projector body.
Wall of the portion different from the rotation center side of the mirror Fresnel plate
By inserting the mirror into the recess provided on the surface,
The feature is that the Rnel panel is held in a horizontal position.
Reflective overhead projector.