JPH0410588Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a safety device for folding a reflective overhead projector (hereinafter referred to as OHP).

[Conventional technology]

In a reflective OHP that has a basic structure consisting of a head, a column, and a base, the column that supports the head is pivoted at its base end and can be folded using this as a fulcrum.When in use, it opens from the folded state and is used as a locking means. It is now held and available for use. Conventionally, when folding such an OHP, the locked state was immediately released by a simple operation such as simply pressing a lock release plate or the like.

[Problem that the invention attempts to solve]

However, with this type of locking mechanism, once the lock is released, the column begins to rapidly rotate due to its own weight, which is not only dangerous for operation, but also causes damage or failure of the device. . In view of these circumstances, the present invention provides a reflective OHP having a locking mechanism that is highly safe and has excellent operability.

[Means and actions for solving problems]

In the reflective OHP according to the present invention, the first engaging member installed on the column and the base are rotatably supported, and the column is rotated in the folding direction by engaging with the first engaging member during projection. a lock lever provided on the base and having a second engagement member that prevents the column from moving and is disengaged from the first engagement member only when the column is rotated in a direction opposite to the folding direction; a release plate that allows the lock lever to rotate in the folding direction by interlocking the lock lever by performing a release operation in a state where the first and second engagement members are disengaged; Control that allows the Fresnel lens to be engaged and detached, and when the Fresnel lens is in the normal position, the Fresnel lens is pushed to release the engagement with the release plate, and when the Fresnel lens is in another rotational position, the release plate is locked. It is equipped with a member.

Therefore, the release plate cannot be operated unless the support column is once rotated in the anti-folding direction, and furthermore, the release plate cannot be operated unless the Fresnel lens is in a normal position where it can be stored.

〔Example〕

1 to 7 are diagrams showing one embodiment of the reflective OHP of the present invention. In FIGS. 1 and 2, 1 is a base, and 2 is installed at one end of the base 1. 3 is a Fresnel lens that is slidably and rotatably supported on the base 1; 4 is a Fresnel lens whose base end is rotatably pivoted from the upright position shown in the cover 2 to the base 1 side; A head 5 having a built-in light source, a projection lens, etc. at its tip is rotatably supported via a shaft 6. A lock pin 9 implanted at one end is rotatably supported by the head 5 via a shaft 10 and engaged with the lock pin at one end to rotate the head 5 in the folding direction (direction of arrow A).
It has a recess 9a and a lock release piece 9b that protrudes downward from the head 5, and the other end has a lock release piece 9b that prevents the lock pin 7 from rotating when the lock pin 7 is disengaged from the recess 9a and the head 5 is rotated in the folding direction.
The lock lever has a key-shaped pin holding portion 9c that can be engaged with the head 5 to hold the head 5 in a predetermined position, and is given a left-handed rotation behavior by a spring 11.

Therefore, since the structure is as described above, if the columns 4, 4 are raised from the base 1 and the recess 9a of the lock lever 9 is engaged with the lock pin 7,
Due to the weight of the head 5, it is supported by the supports 4, 4 at a predetermined position as shown in FIG. When folding the head 5 in such a state, the recess 9a and the lock pin 7
Since the lock release piece 9b cannot be moved to the left in this state, the head 5 is engaged with the lock release piece 9b.
cannot be folded, but once the head 5 is lifted in the anti-folding direction (in the direction of arrow B), the lock pin 7 will be disengaged from the recess 9a, so it is impossible to operate the lock release piece 9b to the left. This makes it possible to rotate the head 5 in the folding direction. The lock pin 7, which has been disengaged from the recess 9a, slides on one side edge of the lock lever 9 and engages with the pin holding portion 9c, whereby the head 5 is folded into a predetermined position relative to the columns 4, 4. Retained. Furthermore, the head 5 can be rotated in the anti-folding direction by operating the lock release piece 9b against the spring 11 and disengaging the lock pin from the pin holding portion 9c, thereby opening the fold. can.

Therefore, when the head 5 is folded, it is not possible to simply operate the lock release piece 9b as in the conventional case.
cannot be rotated in the folding direction, and once this
Since the lock release piece 9b cannot be operated until it has been pushed in the anti-folding direction, the head 5 will not suddenly start rotating due to careless operation of the lock release piece 9b, and the folding operation will be prevented. safety can be improved.

Further, in FIG. 3, reference numeral 12 indicates a lock pin implanted at one end of a support lock plate 13 fixed to the support support 4 whose base end is supported on the base 1 side via a shaft 14, and 15 indicates an upright position of the support support 4. At times, as shown in the figure, the recess 15a that engages with the lock pin 12 to prevent rotation of the support column 4 in the folding direction (in the direction of arrow A') and the right-handed movement provided by the spring 17 cause the release plate 18 to come into contact with the bottom of the release plate 18, which will be described later. Contacting lock release piece 15b
The lock lever 18 is a release plate mounted within the cover 2 so as to be slidable by a predetermined stroke relative to the base 1. In this embodiment as well, since the lock pin 12 is engaged with the recess 15a when the support 4 is folded up and the support 4 is raised, the engagement cannot be released as it is even if the release 18 is operated. cannot be folded. That is, from this engaged state, the support column 4 is moved in the anti-folding direction (arrow
B' direction) Lock pin 12 is stopped by stopper 15c
The recess 15a and the lock pin 12 are rotated until it comes into contact with the lock pin 12, and the release plate 18 pushes the lock release piece 15b against the spring 17.
can be disengaged, and then the strut 4 can be rotated in the folding direction and folded. Therefore, the support column 4 cannot be folded only by operating the release plate 18, and safety can be improved.

Further, in FIGS. 4 to 7, 18a is a lock piece fixed to the release plate 18 and extended downward, and 19 is a pedestal 20 fixed to the base 1 side.
The control has elongated holes 19c, 19c guided by guide pins 21, 21 fixed to the pedestal 20, is slidably mounted on the pedestal 20, and is given a movement habit to the right in FIG. 5 by a spring 24. The plate 22 is fixed to one end of the control plate 19 and protrudes from the inside of the cover 2 toward the base 1 side. When the Fresnel lens 3 is in the normal position (retractable position) on the base 1 as shown in FIG. The control plate 19 is brought into contact with one side end of the Fresnel lens 3 and moved against the spring 24 to the position shown by the broken line in FIG. A hook 23 is fixed to the other end of the control plate 19 and is moved to the predetermined position shown in the figure by a spring 24 together with the control plate 19 without contacting the Fresnel lens 3 when the Fresnel lens 3 is not in contact with the Fresnel lens 3. When it is in the position, it cannot come into contact with the lock piece 18a, and when it is not in the normal position, the lock piece 18a
This is a lock piece that comes into contact with a and prevents the release plate 18 from being pushed. Therefore, when the Fresnel lens 3 is not in the correct position on the base 1, the release plate 1
Since the column 8 cannot be pushed, even if the column 4 is rotated in the anti-folding direction in order to fold the column 4, the engagement between the recess 15a and the lock pin 12 cannot be released, and in this case, the column 4 cannot be folded. Cannot be operated. That is, in this case, a simple release plate 1
Not only can the support column 4 not be folded only by the operation 8, but it also cannot be folded even when the Fresnel lens 3 is not in its normal position, so a double safety measure is taken when folding the support column 4.

In the above embodiment, the lock lever 9, the support column 4, and the lock lever 15 may be provided with either a lock pin or a recess that engages with the lock pin, but the present invention is not limited to the embodiment described above.

The lock pin 12 or the recess provided on the support column 4 constitutes a first engagement member, and the recess 15a or lock pin provided on the lock lever 15 constitutes a second engagement member.

[Effect of idea]

As mentioned above, the reflective OHP safety device according to the present invention can improve the safety of operation when folding the support, is easy to operate, and furthermore prevents damage to Fresnel lenses and equipment failure. It has excellent practical advantages.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing a reflective OHP to which the present invention is applied, Figure 2 is a partial sectional view of a head to which the safety device of the present invention is applied, and Figure 3 is a view of the head to which the safety device of the present invention is applied. 4 and 5 are partial sectional views of the safety device with a control member, and FIGS. 6 and 7 are partial sectional views of the base and support of the safety device of the present invention. FIG. 3 is a plan view showing the relationship between the position of the 1... Base, 2... Cover, 3... Fresnel lens, 4... Support, 5... Head, 7, 12...
Lock pin, 9, 15...Lock lever, 9a,
15a... recess, 9b... lock release piece, 18...
...Release plate, 19...Control board, 22...Hook, 2
3...Lock piece.

Claims (1)

[Claims for Utility Model Registration] A head containing a light source and a projection lens, a column that pivots the head at its tip, a base that pivots the column, and a base that is horizontally rotatable on the base. A reflection type overhead projector having a Fresnel lens supported by the support and whose head and support can be folded, wherein a first engaging member installed on the support and a rotatable member attached to the base. The first engaging member is supported and engaged with the first engaging member during projection to prevent rotation of the support in the folding direction, and only when the support is rotated in the opposite direction to the folding direction. a lock lever having a second engaging member that is disengaged; and a lock lever provided on the base and operating the lock lever in a state in which the first and second engaging members are disengaged. a release plate that allows the lock lever to rotate in the folding direction of the column; and a release plate that is removable from the release plate and that is pushed by the Fresnel lens when the Fresnel lens is in a normal position. 1. A safety device for an overhead projector, comprising: a control member that disengages the Fresnel lens from engagement with the release plate and locks the release plate when the Fresnel lens is in another rotational position.