JPH01136135A - Overhead projector - Google Patents

Abstract

PURPOSE:To protect a discharge hole and to prevent dust, etc., from invading to the inside of a main base from the discharge hole by pushing a projecting head down and housing it in the main base when an overhead projector is not used, and providing the discharge hole dissipating heat generated by a light source in the recess of the housing part to the outside of the main base. CONSTITUTION:The title device is provided with the housing part 23 which houses the projecting head 9 when the head 9 is pushed down in the direction of the main base at the end of the use of the overhead projector, and with the discharge hole 24 in the recess of the housing part 23. The projecting head 9 is pushed down and housed in the housing part 23 when the overhead projector is not used, therefore the projecting head 9 covers the discharge hole 24. When the overhead projector is used, the projecting head 9 is pulled up, thereby opening the discharge hole 24 so that the heat of the light source is dissipated to the outside of the main base. Thus the discharge hole can be protected, and the invasion of dust, etc., into the discharge hole can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overhead projector, and more particularly to a portable overhead projector.

[Conventional technology]

Some overhead projectors that have been used in the past include a system in which a transparent original set on the top surface of the base of the main body is illuminated from below by a lamp installed inside the main body, and the projected light is projected toward a screen by a projection head. There is something I did. Most of these overhead projectors are of the vertical type, and when not in use, the projection head is folded down toward the base of the main body, and the projector is stored or carried.

[Problem that the invention seeks to solve]

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

The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide an overhead projector that can protect the exhaust hole and prevent dust from entering the exhaust hole. This is the purpose.

[Means for solving problems]

In order to achieve the above object, the present invention provides a storage section in which the projection head is stored when the overhead projector is used and the projection head is laid down toward the base of the main body, and an exhaust hole is provided at the back of this storage section. This is what I did.

[Effect]

When the overhead projector is not in use, the projection head is folded down and stored in the storage section, so the exhaust hole is covered by the projection head. When in use, the projection head is raised and the exhaust hole is opened to release 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, which shows the external appearance of an overhead projector embodying the present invention in use, a transparent Fresnel plate 2 is fixed to the top of a box-shaped base 1. As shown in FIG. 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.

At the rear of the right side surface 6 of the base 1, an arm 7 rotatable along this side surface 6 is pivotally attached with a shaft 8.

This arm 7 is bent at a right angle at a corner 7a, and a projection head section 9 is attached to the tip. When the arm 7 is rotated to the illustrated upright position, the projection head section 9 is supported at a predetermined projection position directly facing the Fresnel plate 2.

A projection lens 11 for enlarging and projecting the light condensed by the Fresnel plate 2 is fitted into the projection head 9. Above the projection lens 11, there are 4
A projection mirror 12 is provided tilted by 5 degrees. This projection mirror 12, which 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. A dial 16 for focusing the projected image and a zoom dial 17 for adjusting the size of the projected image are provided on the front surface of the projection head section 9.
is provided.

On the other hand, when the arm 7 is laid down along this side surface 6, the arm portion 7b is attached to the side surface 6 of the base to which the arm 7 is pivoted.
Arm holder 1 that stops the holder from moving downward.
8 is provided. A handle 19 used 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 which is laid down from being grasped as 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. This storage section 2
An exhaust hole 24 that is covered with a net is provided at the back of the base 1.
Heat generated by a lamp (not shown) installed inside is exhausted from here. Also, on this side 22, a power switch 26 is provided.
Also provided.

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 irradiation 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 l from the exhaust hole 24.

The fan 26 is activated when the power switch 26 is turned on, sucks air through an intake hole 37 provided on a side surface 36 on the rear side, and discharges this air through an exhaust hole 24.

The operation of the overhead projector having the above configuration will be described below. First, as shown in FIG.
Pull up to apply a click stop. Then, place the transparent original 3 on the Fresnel plate 2, and turn on the power switch 26.
ONL, and the lamp 31 in the base 1 emits light, the image of the transparent original 3 illuminated by the lamp is formed on the screen via the projection lens 11 and 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 starts operating at the same time as the power switch 26 is turned on, sucks air through the intake hole 37 provided on the rear side surface 36, and transfers this air to the exhaust hole 37.
Forced exhaust from 4.

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. This lowering operation causes the projection head section 9 to be housed in the housing section 23 and cover the exhaust hole 24. In this way, when not in use, the projection head section 9 itself, which is laid down, closes the exhaust hole 2.
4, the exhaust hole 24 can be covered without using any other protective member.

〔Effect of the invention〕

As described in detail above, in the overhead projector of the present invention, when not in use, the projection head is folded down and stored in the storage section provided at the base of the main body, and the light source is located at the back of this storage section. An exhaust hole is provided to release the generated heat to the outside of the base of the main body. Therefore, when the projection head is used in an upright position, the exhaust hole is opened to provide heat dissipation, and when the projection head is not in use, the exhaust hole can be reliably covered by the projection head.
It is possible to protect the exhaust hole and prevent dust from entering the base of the main body from the exhaust hole without adding any new members or the like.

[Brief explanation of the drawing]

FIG. 1 is an external view showing an example of the form in use of an overhead blower 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. Figure 3

Claims (3)

[Claims] (1) A light source that is installed inside the main body base and illuminates the transparent original set on the top surface of the main body base from below; There is a projection head that projects toward the camera, and when not in use, the projection head is folded down toward the base of the main body and stored in a designated storage section.The projection head is installed at the back of this storage section and is covered by the projection head when not in use, but is opened when in use. and an exhaust hole for discharging heat from the light source. (2) The overhead projector according to claim 1, wherein the storage section 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.