Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Physical dimension specified
Reexamination Certificate
2001-10-18
2003-10-07
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Physical dimension specified
C428S332000, C428S412000, C428S430000, C428S441000, C428S442000
Reexamination Certificate
active
06630235
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a bulletproof glass screen which is used for applications requiring protectiveness and transparency and a bulletproof glass screen device based on such a bulletproof glass screen.
A conventional bulletproof glass generally consists of a laminate of heat-treated, annealed glass plates whose thickness is from 10 to 12 mm. This kind of bulletproof glass as a laminate of, for example, four glass plates has an overall thickness of 40 to 50 mm. A laminate like this requires a high production cost and is poor in machinability and also weighty, which leads to poor workability. There are bulletproof screens which use polycarbonate resin plates instead of glass plates. However, this type of bulletproof screen requires a very high production cost and the surface may become yellowish for aged deterioration. In addition, since it takes the form of a plate, the yellowish surface or other part as a phenomenon of deterioration with time tends to be conspicuous.
An example of conventional bulletproof glass is the published Japanese translation of PCT international publication for patent applications No. 506056/1991. This bulletproof glass screen device is structured of a plurality of glass plates. Each surface of glass plates is covered by fracture-proof safety film. The glass plates are spaced at regular intervals. However, when this structure is used, the device must be wide and relatively heavy, resulting in a deterioration in workability.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above circumstances and provides a bulletproof glass screen and a bulletproof glass screen device which are relatively lightweight and workable and provide a relatively high protectiveness and transparency.
In order to achieve the above-described object, a structure of the present invention is explained by reference to drawings illustrating embodiments of the invention. Each of these bulletproof glass screens
1
(
1
-
1
to
1
-
7
) is characterized in that at least one of the front and rear faces of a laminated glass
2
is covered by at least one sheet of plastic fracture-proof film
3
. The fracture-proof film
3
can be attached only to at least one of the front and rear faces of the bulletproof glass screen
1
. It is desirable to attach the fracture-proof film
3
to the rear side of the bulletproof glass screen
1
, or the opposite of its impact surface. There are cases in which the condition of the surroundings including the inside or outside of a building or room is known and which direction bullets are most likely to come from is obvious. Usually it is thought that bullets are more likely to come from the outside of a building than from the inside or more likely to come from the outside of a room than from the inside. Therefore, in such cases, it is effective that the bulletproof glass screen's inside surface which is inside the building or room is covered by fracture-proof film. However, if the building is used as a shooting gallery or the like, it is more likely that bullets come from the inside of the building; thus in this case it is effective that the bulletproof glass screen's outside surface which is outside the building or room is covered by fracture-proof film.
The fracture-proof film
3
can be attached to both the front and rear faces of the bulletproof glass screen
1
. If the fracture-proof film
3
is attached to both the front and rear faces of the screen, it is useful for a situation in which bullets may impact against both the front and rear faces of the bulletproof glass screen
1
. When it is predictable that under some condition (during a certain period or time zone, etc.) bullets fly from a specific direction (for example, if shooting galleries are located on both sides of the screen and are alternately used for firing in the morning and afternoon for the reason of time-consuming preparation of the shooting galleries or other reason), covering of both the front and rear faces of the bulletproof glass screen
1
by the fracture-proof film
3
is effective. Also there is another situation in which, although bullets usually fly from a fixed direction, bullets can fly from the opposite direction in some special occasions. Covering of both the front and rear faces of the bulletproof glass screen
1
by the fracture-proof film
3
is also effective that not only the case where bulletproofing is primarily intended as a countermeasure against shooting from the outside of the building, but also the case where it is required to prevent bullets or splinters of a bullet from hitting a passer-by outside the building due to shooting or an explosion inside it.
Further, in the case of a bulletproof glass screen device as mentioned later, if the bulletproof glass screen
1
is assembled in the field where the device is installed, covering of both the front and rear faces of the bulletproof glass screen
1
by the fracture-proof film
3
is effective because there is a possibility of assembling the screen the wrong way.
The fracture-proof film
3
is generally made to adhere to all or virtually all the above-said surface of the bulletproof glass screen
1
. All or virtually all the above-said surface refers to all or virtually all the surface of the screen except the rim for fitting the bulletproof glass screen
1
, for example, into a window frame. If, for fitting into the window frame or in connection with any other thing pertaining to the building, some part of the surface of the bulletproof glass screen
1
is substantially exposed to the outside, it is a good idea to cover it by the fracture-proof film
3
. It is also possible to attach the fracture-proof film
3
to
20
part of the above-said surface of the bulletproof glass screen
1
. This means that the fracture-proof film
3
may be attached to the part of the bulletproof glass screen
1
which bullets may hit. If part of the bulletproof glass screen surface exposed to the outside is covered by the fracture-proof film
3
, a bulletproof material as mentioned later like a metal net or metal board may be provided facing the surface of the bulletproof glass screen
1
which is not covered by the fracture-proof film
3
.
The above-mentioned fracture-proof film
3
is plastic film: it may be, for example, polyethylene resin, polyester resin, vinyl chloride resin or polycarbonate resin film.
At least one sheet of above-said fracture-proof film
3
is used; however, the number of sheets used may be as desired or varied depending on the structure of the laminated glass
2
of the bulletproof glass screen
1
or the environment or situation in which it is installed. As the environment or situation in which the laminated glass
2
is installed changes, the number of sheets of fracture-proof film
3
may be increased or decreased later. Furthermore, the fracture-proof film
3
may be later attached to the already installed laminated glass
2
with no fracture-proof film
3
in order to make up a bulletproof glass screen
1
according to the present invention. When more than one sheet of fracture-proof film are attached to the laminated glass
2
, the fracture-proof film sheets may be of the same type or of different types.
One sheet of fracture-proof film
3
may comprise a single layer of film. Alternatively, it may be a multi-layered film in which a plurality of single film layers of the same plastic material are laminated, or a multi-layered film in which a plurality of single film layers of different plastic materials are laminated. It is desirable that one sheet of fracture-proof film
3
is a multi-layered film for the sake of increased strength and comprises layers of the same plastic material for manufacturing ease. For instance, it is recommended that it be a multi-layered film as a laminate of plural polyethylene plastic film layers.
In manufacturing a sheet of multi-layered fracture-proof film
3
, a plurality of single layer plastic films are laminated, pressed and bonded to each other in a way that their dra
Oshima Yasunobu
Yoshida Kenji
Bunka Shutter Co., Ltd.
Kanesaka & Takeuchi
Nakarani D. S.
LandOfFree
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