JPH06160978A - Overhead projector - Google Patents

Abstract

PURPOSE:To provide an overhead projector provided with a mechanism for preventing the end part of a projection mirror for an overhead projector from coming into contact with an original platen and also for preventing a head part from coming into contact with a cover. CONSTITUTION:A pop-up cover is rotated up to a position where the pop-up cover does not come into contact with the projection head part 1 even in the case that the projection head part 1 starts to rotate under the rotation of a supporting arm part 2 when a pop-up lever 25 is operated. After the projection head part 1 is set on a projection allowable position and a main switch 24 is turned on and the original 29 is set on a stage 20, the original 29 is enlarged and projected. A mirror stopper 31 is installed on the lower part of the supporting arm part 2 in order to prevent the projection mirror 21 from coming into contact with the original platen 20 when the overhead projector is folded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead projector for enlarging and projecting an image of a document.

[0002]

2. Description of the Related Art Overhead projectors that illuminate an original document on which characters and figures are recorded on a transparent sheet and project the image of the original document on a screen in an enlarged manner are classified into a reflective type and a transmissive type due to the difference in illumination method. There are types. In the reflection type, the light source for illuminating the original is built in the projection head section, and the original is illuminated from the lower surface by the reflected light from the mirror Fresnel plate provided on the stage, and the projection lens provided in the projection head section. And project through a projection mirror. In the transmissive type, a light source for illuminating an original is provided on the lower surface side of the stage, the original is irradiated from the lower surface side through a Fresnel lens provided on the stage, and is also projected through a projection lens and a projection mirror.

In many of these overhead projectors, a support arm is rotatably attached to a pedestal portion provided with a stage, and a projection head portion is rotatably attached to a tip end portion of the support arm for easy carrying. Is pivoted on. The support arm and the projection head unit can be folded along the pedestal when being carried. Many of them work together with the support arm so that the projection head comes to the set position directly facing the stage when the support arm is raised upward to enable the overhead projector. There is.

As an interlocking mechanism for rotating the projection head portion to the set position by the standing motion of the support arm, the applicant of the present invention rotates the projection head portion with respect to the rotating direction when the support arm stands up to the use position. I am proposing that the direction is reversed. According to this, even if the projection head unit is rotated from the time when the rotation of the support arm is started, the projection head unit does not hit the stage, so there is an advantage that the interlocking mechanism between the two can be simplified.

[0005]

However, since the projection mirror provided in the projection head portion is erected at an angle of about 50 ° in the used state, the projection mirror moves in the rotating direction of the support arm as described above. On the other hand, when the rotation direction of the projection head unit is interlocked in the opposite direction, when the support arm is rotated to a position near the unused position, the tip of the projection mirror standing upright from the projection head unit will move to the stage. The problem of hitting and damaging the stage arises.

Further, a cover is used to protect the stage and projection head section of the overhead projector when not in use. A part of such a cover is also used as an anti-glare cover so that bright light from the stage does not reach the surroundings when the overhead projector is used, and in many cases, it is integrally connected to the support arm. However, as described above, when the rotation direction of the support arm and the rotation direction of the projection head section are interlocked in opposite directions, the projection head section rotates so as to traverse the cover fixed to the support arm. Cannot be increased. Therefore, there is a drawback that the cover on the supporting arm side cannot have a sufficient antiglare effect.

The present invention has been made to solve the above-mentioned problems, and in using a mechanism for rotating the projection head portion in the opposite direction in conjunction with the rotation of the support arm, a projection mirror and a stage, or a projection unit is used. It is an object of the present invention to provide an overhead projector that prevents interference between the head portion and the antiglare cover.

[0008]

In order to achieve the above object, when the support arm is rotated in a direction in which the projection head part and the support arm are folded along the pedestal part, the projection head part is rotatable about the projection head part. To prevent the end of the attached projection mirror from contacting the stage, a pressing member is formed on the support arm to prevent the projection mirror from rotating, and the projection head and support arm are folded along the pedestal. In addition, when rotating the support arm of the overhead projector from the state where the upper cover covers the upper surface of the overhead projector main body to the use position, keep the upper cover so that part of the projection head part does not contact the upper cover. A mechanism for urging the projection head to rotate to a position where a part of the projection head does not contact the upper cover is provided before the projection head is rotated. It is.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 shows a reflection type overhead projector embodying the present invention in which a support arm stands upright,
FIG. 3 is an external perspective view showing a state in which a document can be projected. The support arm 2 pivotally mounted on the pedestal portion 33 including the Fresnel mirror and the stage 20 is set in a predetermined position by rotating the projection head portion 1 in the direction opposite to the rotation direction of the support arm 2. . Then, if the projection mirror 21 is folded up by a mirror stopper 31 provided below the support arm 2 so that the projection mirror 21 does not come into contact with the stage 20 when the overhead projector is folded, the overhead is raised. The projector can project.

FIG. 5 is an exploded perspective view showing the outline of the interlocking mechanism of the projection head portion and the support arm in the reflection type overhead projector embodying the present invention. Base 3
Brackets 17a, 17
b is fixed, and the shaft 13, which is the rotation center of the support arm 2, is fixed to the brackets 17a and 17b so as not to rotate. In addition, in this figure, illustration of one side cover of the support arm 2 is omitted.

A boss 18 through which the shaft 13 is inserted is integrally provided at the lower end of the support arm 2, and the support arm 2 is provided with a shaft 13.
It is rotatable around. Further, a gear 10 is non-rotatably attached to the shaft 13. A pair of pulley shafts 11a and 11b is rotatably inserted in the support arm 2. Pulleys 4 and 8 are fixed to the pulley shafts 11a and 11b, respectively, and they rotate together. The wire 5 is plowed between the pulleys 4 and 8, and the rotation of the pulley 8 is transmitted in the opposite direction to the other pulley 4. Reference numeral 6 indicates an adjusting component for preventing the wire 5 from loosening.

The pulley shaft 11b has the number of teeth of the gear 10
The gear 9 of less than half is fixed and meshed with the gear 10. When the gear 9 rotates, the pulley shaft 11b and the pulley 8 rotate together. The other pulley shaft 11a is a shaft integrally fixed to the projection head unit 1, and when the pulley 4 rotates, the projection head unit 1 rotates in the same direction via the pulley shaft 11a.

The support arm 2 is partitioned by a partition wall 16, and a gas spring 7 is incorporated inside the partition wall 16. One end of the gas spring 7 is attached to the inner wall of the support arm 2, and the other end is the pin 1 planted in the bracket 17a.
It is attached to 2. As is well known, the gas spring 7 is a cylinder in which a gas is sealed and a piston is fitted in such a manner that the piston can freely move in and out. By applying an appropriate load in the compression direction, the support arm 2 can support the weight of the projection head unit 1. It prevents them from falling abruptly. The gas spring 7 may be rotated around the pin 12 by the rotation of the support arm 2 and partially protrude from the notch 3 of the support arm 2. However, the gas spring 7 appears in appearance by the front cover 32 shown in FIG. There is no such thing.

FIG. 6 is a plan view showing a mechanism for erecting the cover of the overhead projector embodying the present invention. The pop-up cover 19 is biased upward by a spring 37, and an arm speed control gear 40 is fixed to the lower part of the pop-up cover 19. The arm governing gear 40 meshes with the governor gear 39 of the governor 38, and prevents the pop-up cover 19 from rapidly rotating upward due to the bias of the spring 37.

A locking claw 35 is provided on the pop-up cover 19 so as to project downward, and when the pop-up cover 19 is in a closed position along the pedestal, a spring 36 engages the locking claw 35. Engaging the pop-up lever 25 biased in the direction,
Against the spring 37 urging upwards, is locked at a closed position along the pedestal.

FIG. 3 is an external perspective view showing the reflective overhead projector embodying the invention in a folded state. The support arm 2 and the projection head unit 1 are lying down at a position directly facing the stage 20. From this state, if the main body cover 26 is rotated toward the projection head unit 1 to cover the whole, it becomes convenient for transportation. The pop-up cover 19 is biased by the spring 37 shown in FIG. 6 so as to rotate in the upright direction, and is shown in FIG. 6 to keep the pop-up cover 19 in a position directly facing the stage 20. When the pop-up lever 25 for releasing the mechanism is operated, the pop-up cover 19 pops up in the upright direction.

FIG. 2 is an external perspective view showing a state in which the pop-up cover stands up in the reflective overhead projector embodying the present invention. The pop-up cover 19 pops up in the upright direction by the biasing force of the spring 37 shown in FIG. 6 and does not come into contact with the projection head unit 1 even if the projection head unit 1 starts to rotate due to the rotation of the support arm 2. It has rotated to the position. The projection head unit 1 is
Contrary to the state in which projection is possible, the document irradiation port 28 and the projection light incident part 27 face upward. It should be noted that the pop-up cover 19 also functions as a cover for preventing glare of a user on the rear side of the overhead projector when the overhead projector is projected when the pop-up cover 19 is upright.

Next, the operation of the above configuration will be described. Support arm 2 when storing the overhead projector
Is laid down substantially horizontally, and the projection head unit 1 is also folded in a posture with its upper surface facing downward, and is completely covered by the main body cover 26. It should be noted that when the support arm 2 is laid down to the storage position shown in FIG. 3, the stage 20 is also lowered by an interlocking mechanism (not shown), and a storage space for the projection head unit 1 is secured.

In use, the body cover 26 is first opened as shown in FIG. Next, when the pop-up lever 25 shown in FIG. 6 is operated against the spring 36, the locking claw 35 engaged with the pop-up lever 25 is released, and the spring 37 is released.
The pop-up cover 19 is rotated upward by the bias of. At this time, the arm speed governing gear 40 fixed to the lower portion of the pop-up cover 19 meshes with the governor gear 39 and interlocks with the governor 38, so that the pop-up cover 19 suddenly rotates upward and becomes an overhead projector. No damage is done. It should be noted that the governor generally suppresses the action of the mechanism interlocking with the action of the hydraulic pressure or the like and controls the speed.

After the pop-up cover 19 has rotated to a predetermined position, the support arm 2 is then gripped and rotated in the upright direction about the shaft 13 so that the gear meshes with the gear 10 fixed to the shaft 13. Thus, the gear 9 rotates clockwise while rolling around the outer periphery of the gear 10. While the support arm 2 is rotated from the fall position to the upright position, the gear 9 moves only on the outer circumference of the gear 10 within a range of half a circumference or less, but the number of teeth of the gear 9 is less than half of the gear 10. , The gear 9 makes almost one rotation during this period, and the pulley shaft 11b and the pulley 8 also rotate clockwise in unison therewith.

When the pulley 8 rotates clockwise in this way, the rotation is transmitted in the reverse direction of the pulley 4 via the wire 5, and the pulley 4 rotates counterclockwise. Since the pulley shaft 11a is integrally connected to the pulley 4 and the projection head portion 1 is fixed to the pulley shaft 11a, when the pulley 4 rotates in the counterclockwise direction, the projection head portion 1 moves toward the tip side of the support arm 2. To rotate counterclockwise. It should be noted that even if the hand is released while the support arm 2 is being raised, the support arm 7 does not fall down due to the action of the gas spring 7.

As described above, if the direction of rotation of the projection head unit 1 is set to be opposite to the direction of rotation when the support arm 2 is erected, from the initial point of the standing operation of the support arm 2. Even if the projection head unit 1 is rotated from the non-use position to the use position, the projection head unit 1 does not hit the stage 20. Therefore, the entire rotation range of the support arm 2 from the fall position to the standing position can be used as an interlocking range between the support arm 2 and the projection head unit 1. Since the load generated when the projection head unit 1 is rotated in conjunction with the support arm 2 can be dispersed evenly over the entire rotation range of the support arm 2, the support arm 2 can be rotated over the entire rotation range. There is no load fluctuation, and the turning operation of the support arm 2 is smooth and agile.

Further, since the projection head unit 1 rotates counterclockwise, there is a possibility that the projection head unit 1 may come into contact with the end of the pop-up cover 19 unless the pop-up cover 19 is completely rotated to a predetermined position. Since the pop-up cover 19 is mechanically rotated to a predetermined position by the mechanism shown in FIG. 6, the pop-up cover 19 does not stop during the rotation. Therefore, after operating the pop-up lever 25 from the state where the pop-up cover 19 is closed as shown in the plan view (A) shown in FIG. 7, the support arm 2 is rotated as shown in the plan view (B). Even if the projection head unit 1 is rotated, the projection head unit 1 is not covered by the popup cover 19
Never come into contact with.

When the support arm 2 is rotated about 80 °, the support arm 2 is locked in the use position by a click mechanism (not shown). Along with this, the projection head unit 1 is shown in FIG.
The overhead projector is set to the use position shown in, and the overhead projector is ready for use. Also, the support arm 2
Since the stage 20 is raised to the use position while standing up, the original 29 is set on the stage 20 and the projection mirror 21 folded up by the mirror stopper 31 provided below the support arm 2 is raised upward. When the main switch 24 is turned on, the image of the original document 29 can be projected on the screen.

FIG. 4 is a schematic view showing the relationship between the support arm 2, the projection mirror 21 and the mirror stopper 31 when stored. During storage, the support arm 2 is unlocked from the position shown in FIG. 4 (A), and then the support arm 2 is laid down toward the stage 20. This allows gear 9
Rolls along the outer periphery of the gear 10 in the opposite direction to that when the support arm 2 stands up. When the gear 9 rolls, the pulley shaft 11
b, the pulley 8 rotates counterclockwise, and the pulley 4 and the pulley shaft 11a rotate clockwise through the wire 5.

When the support arm 2 is laid down toward the stage 20, the end of the projection mirror 21 eventually comes into contact with the mirror stopper 31 and extends along the projection head 1 as shown in FIG. 4 (B). Is rotated to. When the support arm 2 is laid down to the storage position shown in FIGS. 1 and 4 (C), the projection mirror 21 moves to the mirror stopper 3
It is folded in a direction along the projection head unit 1 by 1 and does not contact the stage 20 and damage the mirror Fresnel surface of the stage 20. Then, the projection head unit 1 can be housed in the space after the stage 20 has descended, in a storage posture with its upper surface facing downward.

Further, the fall of the support arm 2 is performed while compressing the gas spring 7, but the load in the compression direction of the gas spring 7 is such that the weight of the support arm 2 and the projection head portion 1 is supported. Therefore, the support arm 2 can be laid down with a light operating force. Of course, even if the user releases his or her hand during the fall, the support arm 2 and the projection head unit 1 will not fall down suddenly due to their weight.

[0028]

As described above, by using the folding mechanism of the overhead projector of the present invention, when the support arm is rotated, the projection head portion is at the same time relatively opposite to the rotation direction of the support arm without delay. In an overhead projector with a structure that rotates in conjunction with the direction, when the support arm is rotated in a direction in which the projection head and the support arm are folded in such a manner as to face the pedestal part, The end of the rotatably mounted projection mirror is prevented from contacting the stage, and the support arm is rotated from the state where the upper cover covers the entire top surface of the overhead projector body to a position where the original can be projected. It is possible to prevent a part of the projection head unit from coming into contact with the upper cover when moving.

[Brief description of drawings]

FIG. 1 is an external perspective view of a reflective overhead projector embodying the present invention in a state in which a document can be projected.

FIG. 2 is an external perspective view of a reflective overhead projector embodying the present invention with a pop-up cover raised.

FIG. 3 is an external perspective view of the reflective overhead projector embodying the present invention in a state in which the support arm is laid down and folded.

FIG. 4 is a schematic view of a cross section of a reflective overhead projector embodying the present invention when seen from the side, showing how the projection mirror moves.

FIG. 5 is an exploded perspective view showing an outline of the interlocking mechanism of the projection head unit and the support arm in the reflective overhead projector embodying the present invention.

FIG. 6 is a schematic diagram showing an outline of a pop-up cover rotating mechanism in a reflective overhead projector embodying the present invention.

FIG. 7 is a plan view showing the outline of the relationship between the pop-up cover and the projection head section in the reflective overhead projector embodying the present invention.

[Explanation of symbols]

 1 Projection Head 2 Support Arm 19 Popup Cover 20 Stage 21 Projection Mirror 25 Popup Lever 31 Mirror Stopper 35 Locking Claw 37 Spring 38 Governor

Claims (2)

[Claims] 1. A pedestal portion on which a stage for placing a document is provided on an upper surface, and a non-use position which is erected from the pedestal portion from an unused position which is axially attached to the pedestal portion and falls down along the pedestal portion. Between a support arm that is rotatable between the two, and a projection lens that is built-in, and that is pivotally attached to the free end side of the support arm and is folded along the support arm from the stored position to the set position facing the stage. In the overhead projector having a projection head that is rotatable between the projection mirror and pivotally mounted under the action of friction between the upright position and the fall position, the support arm is not used. From the storage position to the set position, and a linkage mechanism that rotates the projection head portion from the storage position to the set position in the direction opposite to the rotation direction of the support arm, and is fixed to the support arm. When the projection head rotates from the set position to the retracted position in conjunction with the rotation of the support arm from the used position to the unused position, the projection mirror is brought into contact with the rear surface of the projection mirror in the upright position and the projection mirror is laid down. An overhead projector comprising: a mirror pressing member that rotates toward a position. 2. A pedestal portion on which a stage for placing a document is provided on an upper surface, and a non-use position which is erected on the pedestal portion from an unused position axially attached to the pedestal portion and lying down along the pedestal portion. Between a support arm that is rotatable between the two, and a projection lens that is built-in, and that is pivotally attached to the free end side of the support arm and is folded along the support arm from the stored position to the set position facing the stage. In an overhead projector having a projection head unit that can be freely rotated between the projection head unit, the projection head unit is supported from a storage position to a set position in conjunction with rotating the support arm from a non-use position to a use position. An interlocking mechanism for rotating the arm in a direction opposite to the rotating direction, and a support arm that is axially attached to the pedestal part and is in a closed position partially covers the support arm from the axial attachment part side and is in the storage position. A cover that partially covers the free end side of the projection head unit and that rotates in the open position to outside the use position of the support arm, a biasing means that biases the cover from the closed position toward the open position, and this cover. Lock means for locking the lock head at the closed position against the biasing means, and by moving the cover to the open position by releasing the lock of the lock means, The overhead projector according to claim 1, wherein the cover is compared from a rotation range.