US2579892A

US2579892A - Outdoor projection screen

Info

Publication number: US2579892A
Application number: US61231A
Authority: US
Inventors: Chauncey S Wright
Original assignee: C S Wright & Co
Current assignee: C S Wright & Co
Priority date: 1948-11-20
Filing date: 1948-11-20
Publication date: 1951-12-25
Anticipated expiration: 1968-12-25

Description

Dec. 25, 195] c, s, wm -r OUTDODR PROJECTION SCREEN 2 SHEETS-SHEET 1 Filed Nov. 20, 1948 lirt INVENTOR WM ATTORNEYS Dec. 25, 1951 c. s.- WRIGHT 2,579,892

QUTDOOR PROJECTION SCREEN Filed Nov. 20, 194B 2 SHEETS-SHEET 2 PJg-J 56 54 5'8 52 3 )35/57/ 59 ss nbm- -s I I 57 PLYWOOD 51 F1 4 N CAULK/NG y\ A I {w 59 7 25 TRANSIT F/N/SH COAT LEAD BASE PAINT CANVAS ON ZINC BASE PAINT iNVENTOR ATTORNEYS Patented Dec. 25, 1951 OUTDOOR PROJECTION SCREEN Chauncey S. .Wright, Dayton, Ohio, assignor to C. S. Wright & Company, Dayton, Ohio,.a partnership.

Application- November 20, 1948', Serial No. 61,231

4 Claims. t i 1 This invention: relates to. projection screens and in particular to projection screens: such as are used, for example, in outdoor theaters".

One of the principal objects of the invention is to provide a smooth surfaced projection screen foroutdoor theaters and the like which. is durable, requires a minimum. of maintenance, and which retains a high quality surface during long periods of use under varied weather conditions without objectionable warping, buckling, cracking or peelmg.

Another object of the" invention is to provide an outdoor projection screen. having a framework or base on which there is mounted a fabric material which is suitably secured. to-the. base, affording asuperior surface for receiving a paint constituting the projection surface, the fabric retaining its continuity and. assuring a smooth image receiving surface.

Still another object of the. invention is to provide sealing means for fabric material mounted on such projection; screens: in order to: protect the same against deterioration by entrance of mois ture or rain and subsequent temperature changes.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings- Fig. 1 is a perspective view of a typical outdoor projection screen;

Figs. 2 and 3 are fragmentary views in elevation of projection screens constructed in accordance with the present invention, broken away at different areas thereof to show the interior-structure of the screens;

Fig. 4 is an enlarged cross-sectional view taken on line 4-4 of. Fig, 3 showing details of construction of the screen shown in Fig. 3.

One of the serious difficulties in connection with the construction of outdoor projection screens is to secure a surface satisfactory for projection which, when exposed to varied weather conditions, particularly rain, moisture, frost and temperature changes, will be durable and will not deteriorate causing warping, buckling, cracking or peeling to such an extent as to distort the clearness or outline of the image projection. Where proper provision is not made for positively sealing the projection surface and retaining the backing or main body section of such projection screens in sealed relation, considerable deterioration results after the screens are subjected to varied weather conditions.

The projection screen which forms the subject matter of this invention, successfully overcomes the difficulties heretofore encountered in this field and. is so constructed as to be durable and serviceable and to withstand ordinary as well as severe weather conditions without objectionable warping, buckling, cracking or peeling, and requires minimum maintenance during long periods of use.

According to the present invention, the outdoor projection screen illustrated in Figs. 1 and 2 embodies a vertically positioned wooden structure- [0 having a main body section H formed by superimposing eight feet by four feet sections of plywood sheeting 12 upon a wooden backing or frame structure I 3, the latter being connected to side supporting walls I 4. The backing or frame structure [3 resembles a lattice and is generally constructed by notching, matching and then nailing together suitable lengths of ordinary two by fours so as to form a network of parallel rectangles having an inside dimension of about four square feet. The projection screen subsurface I5 which has a typical dimension of thirty-six feet by forty-eight feet, is produced by securing four feet by eight feet strips of an asbestos sheeting or lumber material It to the main body section H by means of nails H or the like. The strips of asbestos material It are generally arranged in a staggered relationship with respect to each other as shown in Fig. 2, the seams between the asbestos material are filled with a caulking material it, and thereafter the entire outer surface is coated with a flat white paint l9. While other types of frame or supporting structures and projection screen sub-surfaces may likewise be used, as for example frames or supporting structures made from metal parts, the structure described above and illustrated in the drawings has been found highly satisfactory in the practicing of the present invention.

The projection screen sub-surface i6 is then providedwith a fabric material 20 which is sealed or ,keylocked to the asbestos material by means of a composition or coating '2 l. The coating composition 2! is of such character that when it is applied to the surface l6, and the fabric material 20 ,is pressed or rolled thereagainst while the composition is still in a fiowable condition, the composition migrates through the interstices of the fabric material 2G and upon drying unites or keylocks the fabric and the asbestos material together and thereby forms a seal or union therewith. A suitable coating composition for this purpose comprises a mixture of lead base pigment, zinc oxide, and a drying oil. The formula given below is representative of a composition which is highly satisfactory.

Lead base pigment -pounds I Zinc oxide do 22 Linseed oil gailons 1 It has been found that when an asbestos material surface is coated rather freely with such composition and a fabric material such as a fine grained canvas is placed thereagainst and rolled,

the composition while still fiuid will migrate through and be absorbed by the canvas and upon drying will produce a smooth surface and in addition form a unitary bond or seal between the I with this embodiment, the two by fours arepositioned on four foot centers so that open rectangular areas of approximately sixteen square feet are defined by the backing structure. The sections of plywood are secured to the structure 3| by any suitable means such as nails 32 and are preferably of such dimension as to completely cover the open areas defined by the lattice-type backing structure 3| as illustrated in Fig. 3. For this purpose, standard sections of 5-ply marine plywood having dimensions of about four feet by eight feet by one-half inch have been satisfactorily employed. Sections of a fire-proof asbes- 11- .tos material 33 such as asbestos lumber which is made from asbestos fibers and Portland cement and is known commercially as 'Iransite, are

then superimposed upon and securely anchored to the face side of the sub-base 36 by the use of nails 34. The sections of asbestos material 33 may be of any suitable size but are preferably cut to the same dimensional lengths and widths as the sections of plywood 36 so .that the slots or seams between the. adjacent sections of plywood and the adjacent sections of asbestos material may be filled in one operation by a suitable caulking material, indicated at 35.

The outer surface of the asbestos lumber material 33 is then coated with a suitable lead base primer paint 31 and after this primer coat of paint has dried, a binding or sealing composition 38 comprising a lead base pigment and zinc is then applied, over which a sheet of fabric such as a fine grained canvas 39 is laid and rolled onto .be applied an ordinary white resin emulsion type paint coating 49, which further enhances the protection of the screen against weather conditions, and in addition provides a whiter image-displaying surface so that images or movies projected on the screen will appear more prominent andclear to the observer. Moreover, if desired, the periphery-of the canvas material which is not utilized 'for displaying images may be painted with any suitable black paint 41.

The invention disclosed herein not only provides a projection screen for outdoor theaters that withstands varied weather conditions without warping, buckling, cracking or peeling, but

-it also provides a screen which has a smoother 4 image-displaying surface than the outdoor projection screens now in use.

The coatings 2| and 38 may be compounded in any suitable manner to produce' cjcompositions of suitable whiteness which will not detract from the white characteristics of the finished projection screen and which may be coated on an asbestos material surface such as described for use in sealing or keylocking the asbestos material to a fabric material such as fine grained canvas or the like.

Furthermore, it has been found that these coating compositions are adapted to be used upon painted asbestos or plywood outdoor projection screen surfaces which are in use today and such surfaces may thereby be converted into a smooth surfaced, durable outdoor projection screen in accordance with the teachings of this invention.

While the method and article herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise. method and article and that changes may be made herein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A projection screen for outdoor theaters including a lattice-type frame, a sheeting of plywood secured thereto, a sheeting of asbestos material secured to said plywood and a fine grained canvas material adhesively united to said asbestos material to provide a substantially smooth image displaying surface.

2.- As a new article of manufacture, a weather resistant projection screen for outdoor theaters having a smooth image displaying surface, comprising a base formed by a plywood sheeting and a sheet of asbestos material secured to a-latticetype frame, said base having a coating of binding material comprising a lead base pigment, linseed oil and zinc, a canvas material united to said base by said binding material, and a coating'on the surface of said canvas material forming the image displaying surface.

3. A projection screen for. outdoor theaters comprising a base formedof a plywood sheeting secured to a lattice-type frame with a sheeting of asbestos material secured to said plywood sheeting, said base having a coating of binding material and an overlying canvas material secured thereto. r

4. A weather resistant projection screen for outdoor theaters comprising a base formed by a lattice-like frame with a sheeting of plywood and an outer sheeting of asbestos lumber secured thereto, said base having a coating containing lead base pigment, linseed oil and zinc, and a canvas material united to said coating to form a smooth image displaying surface.

CHAUNCEY s WRIGHT.

REFERENCES CITED The following references .are of record in the U-NITED' 'sTATEs PATENTS Name Number Date 1,043,988 Williams Nov. 12, 1912 1,129,933 Wedemann' Nov. 2, 1915 1,347,761 Shay July 27, 1920 1,487,747 Lassen Aug. 26, 1924 1,513,570 Tischer Oct: 28, 1924 1,806,864 Pallemaerts May .26, 1931