JPH0455488B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an overhead projector;
More specifically, the present invention relates to a portable overhead projector.

[Conventional technology]

Conventionally used overhead projectors have a transparent original set on the top of the base of the main body, which is illuminated from below by a lamp installed inside the main body, and this projection light is directed onto a screen by a projection head and projected. There is something I tried to do. Most of these overhead projectors are of the portable type, and when not in use, the projection head is folded down toward the base of the main body and can be stored or carried around.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned overhead projector, in order to radiate the heat generated by the lamp to the outside of the main body, a cooling fan is provided inside the main body of the overhead projector, and a cooling fan is installed on the side of the main body. An exhaust hole is provided to exhaust the air to the outside of the main body. However, such exhaust holes are covered with a net or the like, and no special cover is provided even when the projection head is folded and stored or carried when not in use. For this reason, dust can easily enter the main body through the exhaust hole, or the exhaust hole can easily break or become deformed due to impact, and in such cases, the internal unit could be damaged.

The present invention has been made to solve the above-mentioned problems, and provides an overhead projector that can protect the exhaust hole and prevent dust from entering the exhaust hole. The purpose is to

[Means for solving problems]

In order to achieve the above object, the present invention forms an exhaust hole on the side surface of the main body base to exhaust heat from a light source for document illumination provided in the main body base, and also forms an open part on the upper surface side of the main body base. A protruding wall surrounding the exhaust hole is provided, and when the arm is folded down after using the overhead projector, the projection head held at the tip of the arm moves to a storage position surrounded by the protruding wall and opens the exhaust hole. It is configured to cover.

[Effect]

When the overhead projector is not in use, the projection head moves to a storage position surrounded by a protruding wall to cover the exhaust hole. When in use, the projection head is raised and the exhaust hole is opened to discharge the heat of the light source to the outside of the main body base.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

〔Example〕

In FIG. 1 showing the external appearance of an overhead projector according to the present invention in use, a transparent Fresnel plate 2 is mounted on the top of a box-shaped base 1.
is fixed. A transparent original 3 is placed on the upper surface of this Fresnel plate 2 while maintaining its flatness. Four hooks 4a to 4d are provided around the Fresnel plate 2 for attaching and detaching a cover 38 covering the upper surface of the base 1 with one touch when not in use.

An arm 7 that is rotatable along the right side surface 6 of the base 1 is pivotally attached to the rear side of the right side surface 6 of the base 1 by a shaft 8. This arm 7 is bent at a right angle at a corner 7a, and a projection head 9 is attached to the tip. When the arm 7 is rotated to the illustrated upright position, the projection head 9 is
It comes to be supported at a predetermined projection position directly facing the Fresnel plate 2.

A projection lens 11 is fitted into the projection head 9 for enlarging and projecting the light collected by the Fresnel plate 2. Above the projection lens 11 is a projection mirror 1 tilted at 45 degrees with respect to the optical axis of the projection lens 11.
2 is provided. This projection mirror 12 reflects the light from the projection lens 11 toward the screen.
is fixed to a mirror holder 13, and this mirror holder 13 is attached to the upper surface of the projection head section 9 so as to be able to rise and fall freely. On the front of the projection head section 9,
Dial 1 for focusing the projected image
6, and a zoom dial 17 for adjusting the size of the projected image.

On the other hand, on the side surface 6 of the base to which the arm 7 is pivoted, there is an arm receiver 18 that receives the arm portion 7b and stops its downward movement when the arm 7 is laid down along the side surface 6. It is provided. A handle 19 for carrying the overhead projector is provided approximately at the center of the side surface 6. A protection plate 21 is provided above the handle 19 and parallel to the handle 19. This protection plate 21 is for preventing the arm 7 that is laid down from being grasped instead of a handle.

A storage section 23 is provided on a side surface 22 of the base 1 facing the projection direction, in which the projection head section 9 is stored when the arm 7 and the projection head section 9 are laid down. The storage section 23 is surrounded on three sides by a rectangular frame-shaped protruding wall with an open upper section.
At the back of this storage section 23 is an exhaust hole 2 that is covered with a net.
4 is provided, and a projection head part 9 is provided for projection.
When the lamp is raised, heat generated by a lamp (not shown) provided in the base 1 is exhausted from here. Also,
A power switch 26 is also provided on this side surface 22.

In FIG. 2 showing a cross section of the base 1, a lamp 31 is provided as a light source approximately at the center of the interior of the base 1. This lamp 31 lights up when the power switch 26 is turned on. Light from the lamp 31 and reflector 32 is focused toward the Fresnel plate 2 by a condenser lens 33. This illumination light passes through the transparent original 3 placed on the upper surface of the Fresnel plate 2, is further condensed by the Fresnel plate 2, and is directed toward the projection lens 11 of the projection head section 9.

On the other hand, a fan 26 is provided inside the side surface 22 facing in the projection direction in order to forcibly exhaust the air inside the base 1 through the exhaust hole 24. This fan 26 is turned on when the power switch 26 is turned on.
When the engine is activated, air is sucked through the intake hole 37 provided on the rear side surface 36 and the air is discharged through the exhaust hole 24.

The operation of the overhead projector having the above configuration will be described below. First, as shown in FIG. 1, the arm 7 is pulled up until the projection head section 9 is almost parallel to the base 1, and the click stop is applied. Then, when the transparent original 3 is placed on the Fresnel plate 2 and the power switch 26 is turned on to cause the lamp 31 in the base 1 to emit light, the image of the transparent original 3 illuminated by the lamp is projected. An image is formed on a screen via a lens 11 and a mirror 12. At this time, the dial 16 is operated to adjust the focus, and the zoom dial 17 is operated to adjust the size of the projected image.

During this time, the fan 26 switches the power switch 26
It starts operating at the same time as the switch is turned on, sucks in air from the intake hole 37 provided on the side surface 36 on the rear side, and forcibly exhausts this air from the exhaust hole 24.

When the projection is completed, the click stop of the arm 7 is released and the arm portion 7b is lowered down until it reaches the arm receiver 18. Due to this lowering operation, the projection head section 9 is stored in the storage section 23 surrounded by a protruding wall.
Cover the exhaust hole 24. In this manner, by covering the exhaust hole 24 with the projection head section 9 itself which is laid down when not in use, the exhaust hole 24 can be covered without using any other maintenance member. Further, since the protruding walls surrounding the storage section 23 on three sides partially surround the projection head 9, external forces are less likely to be applied to the projection head 9 when not in use.

〔Effect of the invention〕

As explained in detail above, in the overhead projector of the present invention, when not in use, at least a portion of the projection head is inserted into the storage position surrounded by the protruding wall, and the projection head is provided at the back of the protruding wall. The exhaust hole is covered by the projection head. Therefore, when the projection head is raised up when in use, the exhaust hole is opened and a heat dissipation effect is obtained, and when the projection head is not in use, the exhaust hole can be reliably covered by the projection head, making it possible to add new parts. It is possible to protect the exhaust hole and prevent dust and foreign matter from entering the base of the main body from the exhaust hole. Furthermore, since the projection head is at least partially surrounded by the protruding wall in the storage position, the projection head can also be protected.

[Brief explanation of the drawing]

FIG. 1 is an external view showing an example of the form in use of an overhead projector embodying the present invention. FIG. 2 is a sectional view of a main part of the base of the main body in FIG. 1. FIG. 3 is an external view of the overhead projector shown in FIG. 1 when it is not in use. 7... Arm, 9... Projection head section, 23...
Storage part, 24...Exhaust hole, 26...Fan, 31
... Lamp, 32 ... Reflector, 33 ... Condenser lens, 37 ... Suction hole.

Claims (1)

[Scope of Claims] 1. A light source that is provided inside the main body base and illuminates the transparent original set on the upper surface of the main body base from below, and a light source that is formed on the side surface of the main body base and that directs the heat from the light source to the outside of the main body base. a protruding wall formed on the side surface of the main body base so as to surround the exhaust hole with the upper surface side of the main body base being an open part; an arm rotatably provided on the main body base; It is held at the tip of the arm, and when in use, is set above the base of the main body by raising the arm, and projects the projection light from the transparent original toward the screen, and when not in use, when the arm is folded down, the projecting light passes through the opening. and a projection head that moves to a walled storage position and covers the exhaust hole. 2. The overhead projector according to claim 1, wherein the exhaust hole is provided on a side surface of the main body base on the projection side. 3. The overhead projector according to claim 1 or 2, wherein the exhaust hole exhausts air from a cooling fan provided in the base of the main body.