Optical: systems and elements – Projection screen – Roll up screen
Reexamination Certificate
1998-08-28
2001-06-19
Mahoney, Christopher E. (Department: 2851)
Optical: systems and elements
Projection screen
Roll up screen
C160S265000
Reexamination Certificate
active
06249377
ABSTRACT:
BACKGROUND OF THE INVENTION
1. (Field of the Invention)
The present invention relates generally to a screen for displaying, on an enlarged scale, an image projected by a projector or a projection TV set and in particular but not exclusively to a portable screen assembly that is easy to carry and can be installed at an optional location such as, for example, on a floor, a table or the like.
2. (Description of Related Art)
An image projected by a projector or, in some cases, a projection TV set is generally displayed, on an enlarged scale, on a reflection type screen or a transmission type screen.
Of such screens, some are generally accommodated in a housing mounted on a ceiling or a side wall, and are electrically or manually extended as occasion demands. Hanging screens or screens with a tripod are used by hanging or locating them at a desired place.
Portable screen assemblies are today available in which a screen is wound around a roll housed in a housing. When such screen assemblies are in use, the housing is initially installed at a desired place, and the screen is subsequently extended by, for example, an extension means somewhat similar to a pantograph by the action of the biasing force of a spring mounted therein.
Recently, the number of meeting or conference increases in companies or offices and there is an increasing demand for a portable screen assembly of a simple structure that is easy to carry with a projector and can be installed on a floor, a desk or a table in a conference room to display an image projected by the projector.
SUMMARY OF THE INVENTION
The present invention has been developed in view of such a demand.
It is accordingly an objective of the present invention to provide an inexpensive portable screen assembly of a simple construction that is handy and easy to carry with a projector.
In accomplishing the above and other objectives, the portable screen assembly according to the present invention includes first and second frames extending parallel to each other, a spring-biased roll rotatably mounted in the first frame, a screen bonded at one end thereof to the second frame and wound around the spring-biased roll, an extender for biasing the first and second frames away from each other to impart a predetermined tension to the screen, and a plurality of support legs for supporting the first and second frames generally vertically during use.
This construction is simple, facilitates carrying and handling of the portable screen assembly, and reduces the manufacturing cost thereof.
Advantageously, the extender includes an elastic member having an elastic force, which is determined appropriately relative to an elastic force of a spring mounted in the spring-biased roll so that the first and second frames can be retained at a desired interval.
By this construction, the width of the screen can be adjusted according to the distance between the screen and a projector.
Conveniently, the extender includes a first pair of rails extending parallel to each other and a second pair of rails extending parallel to each other, with the first pair of rails hingedly connected to the second pair of rails.
Alternatively, the extender includes a pair of rails hingedly connected to each other at first ends thereof and also hingedly connected to the first and second frames, respectively, at second ends thereof.
Because only a pair or two pairs of rails are needed for the extender, extension or folding of the extender prior to or after the use of the portable screen assembly can be readily performed.
Advantageously, the first and second frames are used as casings for accommodating and protecting the spring-biased roll, the screen, and the extender when the portable screen assembly is not in use.
By this construction, the two frames service both as the supporting members for supporting the screen and the casings for protecting internal component parts and, hence, the portable screen assembly can be made compact and inexpensive.
Again advantageously, each of the plurality of support legs includes a plurality of first walls formed thereon and having respective projections formed therewith, while each of the first and second frames includes a plurality of second walls formed thereon.
By this construction, the support legs are retained as extended by causing the first walls to abut against the second walls, respectively, while the support legs are folded by releasing abutment of the first walls against the second walls. Because a force applied to each support leg can be dispersed by virtue of engagement between the plurality of first walls and the plurality of second walls, even a soft and fragile material such as, for example, a resin can withstand a relatively large force, reducing the manufacturing cost of the support legs.
Conveniently, each of the projections has a first inclined surface formed on one side thereof, wherein a lead-in force of each support leg onto an associated one of the first and second frames is generated during folding of the support leg by causing the first inclined surface to abut against an edge of an associated one of the second walls.
This construction requires no additional leg locking means to lock the support legs at their rest positions, making it possible to simplify the construction of the support legs and to manufacture the support legs at a low cost.
Also conveniently, each of the projections has a second inclined surface formed on the other side thereof, wherein the second inclined surface is in abutment with the edge of the associated one of the second walls when each support leg has been extended, preventing an external force from damaging the support leg.
In the above-described construction, the first and second inclined surfaces extend so as to cross each other.
REFERENCES:
patent: 354450 (1886-12-01), Tripp
patent: 1915944 (1933-06-01), Nagel
patent: 1981444 (1934-11-01), Wittel
patent: 5438780 (1995-08-01), Winner
patent: 5581401 (1996-12-01), Takamoto et al.
patent: 5706130 (1998-01-01), Rosen
patent: 5798861 (1998-08-01), Doat
patent: 5839706 (1998-11-01), Liu
patent: 4-331943 (1992-11-01), None
Omura Tetsujiro
Seki Kazuharu
Takamoto Hideo
Izumi-Cosmo Co., Ltd.
Mahoney Christopher E.
Wenderoth , Lind & Ponack, L.L.P.
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