US3140742A

US3140742A - Portable movie screen

Info

Publication number: US3140742A
Application number: US245600A
Authority: US
Inventors: Edward J Petrick; Hillard J Bieschke
Original assignee: Knox Manufacturing Co
Current assignee: Knox Manufacturing Co
Priority date: 1962-12-18
Filing date: 1962-12-18
Publication date: 1964-07-14
Anticipated expiration: 1981-07-14

Description

y 1964 E. J. PETRICK ETAL 3,140,742

PORTABLE MOVIE SCREEN 2 Sheets-Sheet 1 Filed Dec. 18, 1962 Edward J y 1964 E. J. PETRICK ETAL 3,140,742

PORTABLE MOVIE SCREEN 2 Sheets-Sheet 2 Filed Dec. 18, 1962 \h w% gm hm MK hm, KW Q B k @W 1 i 1: L 9% T 0 mm b .m g 3 MR, wb VYNM w 1 H. .r w w v .Wh \Nv Tm kw United States Patent 3,140,742 PORTABLE MOVIE SCREEN Edward J. Petrick, Park Ridge, and Hillard J. Bieschke, Schiller Park, Ill, assignors to Knox Manufacturing Co., a corporation of Illinois Filed Dec. 18, 1962, Ser. No. 245,600 6 Claims. (Cl. 16024) This invention relates to portable movie screens, and more particularly to a new and unique structure for applying tensioning forces to the screen surface in open position.

Heretofore a problem has existed, especially in the less expensive movie screens, in attempting to provide a movie screen surface which in open position is relatively flat. Wrinkles or creases in the reflecting surface seriously detract from the clarity of the image made by the reflective light. The more expensive screens frequently utilize a tensioning yoke in combination with tensioner mechanisms to pull the screen taut into a substantially planar condition. These devices add substantial amounts to the total cost of such portable movie screens.

The primary object of the present invention is to provide a movie screen having a tensioning structure which functions upon an entirely new principle of operation to afford tautness and planarity to a movie screen surface in open position.

Another object is to provide a portable screen device in which the screen tensioning mechanism functions in a dual role so as to tension the screen surface and also to anchor the free end of the screen to the supporting bar or slat.

A further object is to provide such a tensioning device as above specified which in addition cooperates with stop means on the screen slat to prevent movement of the free end of the screen longitudinally of the supporting bar.

Still another object is to provide a tensioning device formed from a resilient strip of pressed cardboard or fibreboard which has a convexly shaped arcuate marginal edge anchored at the ends and at a point or points intermediate the ends to the free end of a movie screen, the resilient strip being supported at its ends by a supporting bar so that forces applied to the movie screen in open position will cause flexing and straightening of the arcuate marginal edge of the resilient strip whereby reactive forces from the resilient strip Will exert stretching forces in the movie screen surface.

The invention is illustrated in a preferred embodiment in the accompanying drawings in which:

FIG. 1 is a fragmentary front elevational view of the portable screen device showing the flexible screen in extended open position;

FIG. 2 is a side elevational view taken from the left of FIG. 1;

FIG. 3 is an enlarged fragmentary broken longitudinal sectional view of the slat of the movie screen device;

FIG. 4 is an enlarged broken plan view of the resilient strip tensioner showing the central slot, the central longitudinal line of weakening, and the opposite arcuate marginal edge portions prior to folding along the line of weakening for attachment to the free end of the movie screen;

FIG. 5 is an enlarged broken side elevational view of the resilient strip tensioner after the strip has been folded along its longitudinal line of weakening, the view show- 3,149,742 Patented July 14, 1%64 ing the concavely shaped arcuate marginal edge portion and the slot of the folded edge portion;

FIG. 6 is an enlarged sectional view taken as indicated on line 66 of FIG. 5; and

FIG. 7 is an enlarged sectional view taken as indicated on line 7-7 of FIG. 3.

In the embodiment illustrated, a standard, generally designated 10, may be provided at its lower end with a foldable leg assembly (not shown) or with other convenient means for holding the standard in upright position. The standard itself is conventional and includes a lower tubular member 11 which is adapted at its upright end to receive a telescoping rod 12 having a bail support 13 at its free end. The telescoping rod 12 can be held in varying positions of extension by a nipping lever or Swedish clamp 14.

Tubular member 11 is provided with an adjustable handle 15 having arms 16 and 17 which slidably embrace the tubular member 11. The handle 15 is also provided with a conventional spring-urged finger lock 18 adjacent the arm 16 so that the handle can be adjustably positioned longitudinally of the tubular member 11.

A mounting surface 26* joins the forward ends of arms 16 and 17 of the handle structure 15. A hollow screen casing 21 is pivotally secured to the mounting surface 20 so that the casing may be swung from a closed position parallel to the standard 16 to an open position, as shown in FIGS. 1 and 2. A spring-urged roller or reel (not shown) is normally rotatably mounted within the casing 21 and affords an elongated supporting element for one end of a sheet of flexible screen material 22 attached thereto. The roller is normally urged so as to tend to pull the attached screen material 22 inwardly through a longitudinal slot (not shown) so that the screen material 22 is wound upon the roller.

The free end of the screen material 22 is uniquely arranged with respect to an elongated supporting bar or slat 23 so as to provide tensioning or stretching forces throughout the flexible screen structure intermediate its opposite laterally disposed

marginal edges

24 and 25 when the flexible screen 22 is pulled to its open exposed position, as shown in FIG. 1. The supporting bar 23 has a bail member 24 secured centrally thereto for hooking over the bail support 13 and suspending the screen material in open position.

The elongated supporting bar 23, as best shown in FIGS. 3 and 7, is preferably constructed in the form of a split tubular sleeve so as to afford a narrow elongated opening 26 of suflicient width to permit the: free end of the screen material to pass therethrough. Plastic caps 27 may be provided to close the opposite open ends of the tubular support member.

The free end of the screen material 22 is. held within the supporting bar 23 by screen tensioning member, generally designated 28. As best shown in FIGS. 4-6, tensioning member 28 is preferably formed from a piece of pressed cardboard or fibreboard provided with a longitudinal line of weakening 30 about which the cardboard may be folded to provide a pair of long

resilient strips

31 and 32. The cardboard is preferably slotted, as at 33, for a purpose which will later be explained. Opposite

marginal edge portions

34 and 35 are concavely arcuately formed so that the two arcuate edges lie adjacent each other along the same arcuate line when the two

strips

31 and 32 are folded against each other. The cardboard or fibreboard tensioning member 28 possesses resilient flexible qualities which cause it, when deformed, to tend always to regain its original shape.

As best shown in FIGS. 3 and 7, the

resilient strips

31 and 32 are positioned to embrace the free end of the screen material 22 and are secured thereto as by stitching r stapling 36. The maximum height of the

strips

31 and 32 is regulated with respect to the diameter of the tubular support member 23 so that the

opposite end portions

37, 37a and 38, 38a of the two strips will make a snug fit Within the tubular support member 23.

Th strips

31 and 32 are first secured to the free end of the screen material 22 and then the screen material is slid longitudinally through the opening 26 until the two strips are completely housed within the tubular support member 23, as shown in FIG. 3. The strips are of such thickness that each of their opposite end portions bear on the opposite sides of the longitudinal opening 26 and against the inner surface of the support member 23, as best shown in FIGS. 3 and 7.

Means are also provided to prevent longitudinal shifting of the strips within the tubular supporting bar 23 after assembly. As herein shown, a pair of stops ii 4-1 are provided in the form of threaded bolts which secure bail saddle 42 to the tubular support member 23, and the saddle in turn secures the bail member 24 to the elongated support member 23. The stops it; and 41 are of such length that each of their shanks is received loosely Within he slot 33 to prevent shifting movement of

thet strips

31, 32 with respect to the supporting bar 23.

The screen material 22 is shown in fully exposed operative position in FIG. 1. As the screen is stretched taut by either adjusting the telescoping rod 12 upwardly or the handle member 15 downwardly, the opposite end portions 37, 37a and 3%, 38a are initially in engagement with the inner surface of the tubular support member 23. However, as additional force in the vertical plane is applied to the screen surface, the concavely bowed

marginal edges

34 and 35 of the resiliently

flexible strips

31 and 32 are caused to be straightened or bowed outwardly from a line indicated at 43 to a line indicated at 44 (see FIG. 3). Thus, the

resilient strips

31 and 32 are deformed downwardly along substantially their entire length, and as said above, their

arcuate edges

34 and 35 are straightened and bear through substantially their entire length upon the internal abutments disposed on opposite sides of the longitudinal opening 26 in the tubular supporting bar 23.

This deformation of the tensioning device 28 sets up inherent reactive forces Within the

resilient strips

31 and 32 so that each of the

strips

31 and 32, in attempting to regain its original shape, exerts stretching or tensioning forces in the screen material 22 entirely across its surface between its

lateral edges

24 and 25. Such stretching forces have been found to be more uniformly applied than even in former types of tensioning mechanisms which are much more expensive so that the resulting viewing surface is substantially planar and wrinkle free.

The principle of operation of the tensioning device, explained and described herein, can equally well be applied to portable wall screens and to screens of a larger size. In portable screens, pressed cardboard tensioners have been found effective. In larger screen surfaces, other appropriate resilient materials can be selected and appropriately formed to carry out the principle of the invention herein described.

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations should be understood therefrom, for some modifications will be obvious to those skilled in the art.

We claim:

1. A movie screen device comprising: a pair of elon- 70 gated support members adapted to be positioned in spaced substantially parallel relation to each other; a flexible screen having a marginal edge secured to one of said support members; and an elongated resilient strip supported at its end portions by the other of said support members,

said strip having an intermediate arched portion facing and bowed away from said one support member, and being secured to the opposite marginal edge of said flexible screen at points adjacent its end portions and at least one intermediate point, whereby movement of said support members away from each other exposes the screen in viewing position and flexes said arched portion toward a straightened condition so that reactive forces in said resilient strip exert tensioning forces in said screen to 0 stretch said screen taut.

2. A movie screen device comprising: a pair of elongated support members adapted to be positioned in spaced substantially parallel relation to each other, one of said support members being a split sleeve affording a narrow longitudinal opening; a flexible screen of reflective material having one marginal edge secured to the other of said support members and the opposite marginal edge extending through said opening of the split sleeve; and an elongated resilient strip positioned within the split sleeve and having an intermediate arched portion facing and bowed away from said other of the support members so that the strip is supported at its end portions, the opposite marginal edge of said flexible screen being secured to the resilient strip, whereby relative movement of the sleeve away from the other of said support members exposes the screen in viewing position and flexes said arched portion toward a straightened condition so that reactive forces in said strip exert tensioning forces in said screen to stretch said screen taut.

3. A movie screen device as specified in claim 2, in which the strip is provided with a slot, and the sleeve is provided with a stop member positioned to extend into said slot to limit longitudinal movement of the strip with respect to the sleeve while permitting flexing of said resilient strip.

4. A movie screen device comprising: a pair of elongated support members adapted to be positioned in spaced substantially parallel relation to each other, one of said support members being a split sleeve affording a narrow longitudinal opening; a flexible screen of reflective material having one marginal edge securcd to the other of said support members and the opposite marginal edge projecting inwardly through said longitudinal opening of the split sleeve; and a pair of elongated resilient strips positioned within the split sleeve on opposite sides of said opposite marginal edge of the screen, each strip having an arched portion facing and bowed away from said other of the support members so that the strip is supported at its end portions on opposite sides of the longitudinal opening of the sleeve, said flexible screen being secured throughout its length to the pair of resilient strips, whereby relative movement of the sleeve away from the other of said support members exposes the screen in viewing position and flexes said arched portions toward straightened condition so that reactive forces in said strips exert tensioning forces in said screen to stretch said screen taut.

5. A movie screen device as specified in claim 4, in which the pair of elongated resilient strips is formed from a single piece of pressed fibreboard having a longitudinally disposed line of weakening symmetrically dividing the fibreboard into a pair of similar flat strip portions each having a concave arcuate longitudinal edge, the strip portions being foldable about the line of weakening to embrace the opposite marginal edge of the flexible screen for securement thereto.

6. A movie screen device comprising: an upright standard; a screen casing centrally pivoted to said standard and having a longitudinal slot therein; a spring-urged roller journaled in the casing; a flexible screen having one marginal edge secured to the roller, the screen being wound around the roller when in closed position and being adapted to be unwound therefrom to exposed viewing position; and screen tensioning means on the free end 75 of the flexible screen and adapted to be suspended from the standard, the screen tensioning means including a split sleeve having a narrow longitudinal opening for receiving the free end of the flexible screen and a pair of elongated flat resilient strips positioned within the split sleeve on opposite sides of said sleeve opening, each of said resilient strips having a concave arcuate edge facing and bowed away from the roller so that the strips are supported at their end portions on opposite sides of the sleeve opening, the free end of the flexible screen being secured throughout its length between said pair of resilient strips, whereby relative movement of the split sleeve away from the roller when the screen is in viewing position flexes said pair of resilient strips and causes said arcuate edges to straighten and bear against the inner surface of the sleeve so that reactive forces in said strips exert tensioning forces in the screen to stretch the screen surface taut.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. A MOVIE SCREEN DEVICE COMPRISING: A PAIR OF ELONGATED SUPPORT MEMBERS ADAPTED TO BE POSITIONED IN SPACED SUBSTANTIALLY PARALLEL RELATION TO EACH OTHER; A FLEXIBLE SCREEN HAVING A MARGINAL EDGE SECURED TO ONE OF SAID SUPPORT MEMBERS; AND AN ELONGATED RESILIENT STRIP SUPPORTED AT ITS END PORTIONS BY THE OTHER OF SAID SUPPORT MEMBERS, SAID STRIP HAVING AN INTERMEDIATE ARCHED PORTION FACING AND BOWED AWAY FROM SAID ONE SUPPORT MEMBER, AND BEING SECURED TO THE OPPOSITE MARGINAL EDGE OF SAID FLEXIBLE SCREEN AT POINTS ADJACENT ITS END PORTIONS AND AT LEAST ONE INTERMEDIATE POINT, WHEREBY MOVEMENT OF SAID SUPPORT MEMBERS AWAY FROM EACH OTHER EXPOSES THE SCREEN IN VIEWING POSITION AND FLEXES SAID ARCHED PORTION TOWARD A STRAIGHTENED CONDITION SO THAT REACTIVE FORCES IN SAID RESILIENT STRIP EXERT TENSIONING FORCES IN SAID SCREEN TO STRETCH SAID SCREEN TAUT.