US3592255A

US3592255A - Automatic tensioning bar for portable picture screens

Info

Publication number: US3592255A
Application number: US803652A
Authority: US
Inventors: Fred S Potter; Walter H Maxson
Original assignee: DA LITE SCREEN CO Inc
Current assignee: DA LITE SCREEN CO Inc
Priority date: 1969-03-03
Filing date: 1969-03-03
Publication date: 1971-07-13
Anticipated expiration: 1988-07-13

Abstract

A vertically extending stretch bar having toggle arrangement therein on the rear of a hanging projection screen to automatically tension the screen surface when the screen is in fully extended position and hidden from view behind the screen case when the screen is rolled up in the case.

Description

United States Patent [54} AUTOMATIC TENSIONING BAR FOR PORTABLE PICTURE SCREENS 7 Clelms, 12 Drawing Figs.

[s2| u.s.c|...... 160/24, 160/351 |51| Int. Cl. i 1 r 1 1 1 1 n 1 1 ..G03b21/58 {50] Field of Search 160/23- [56] References Cited UNITED STATES PATENTS 3,191,663 6/1965 Bieschke 160/24 3,314,467 4/1967 Jacobson .1 160/24 Primary Examiner-J. Karl Bell Attorny- Rummler and Snow ABSTRACT: A vertically extending stretch bar having toggle arrangement therein on the rear of a hanging projection screen to automatically tension the screen surface when the screen is in fully extended position and hidden from view behind the screen case when the screen is rolled up in the case.

PATENTEUJUUBIQH 3,589,255

SHEET 1 OF 2 WALTER H M4 SON PATENTEU JUL 1 3197| 3.592.255

SHEEI 2 [1F 2 I gT/O I/VVENTORS'. FRED S. POTTER WAL TER H. yam W 9 W AUTOMATIC TENSIONING BAR FOR PORTABLE PICTURE SCREENS SUMMARY OF THE INVENTION The provision of a stretch bar incorporated as a permanent part of a hanging-type projection picture screen wherein when the screen fabric is fully wound on its spring roller, i.e., in nonoperative position, the stretch bar will be substantially hidden from view behind the screen casing and when the screen fabric is in operative position, i.e., fully extended, the stretch bar will be out of sight behind the screen, and will automati- :ally tension the screen fabric, and lock the fabric in extended position, and will prevent the fabric from being pulled off the apring roller. The provision of a stretch bar in which both listal ends are pivotally secured, one end to the case, medially at its ends, and the other end to the saddle and medially .hereof. The provision of a stretch bar wherein the same is in we pieces with the end loosely held together by a short link or oggle to hold the screen fabric in fully stretched position inder tension and in locked position, and handle means to vithdraw the fabric from inoperative position to operative and ice versa, and simultaneously operate the stretch bar to lock ll'ld unlock the toggle.

FIG. I is a rear elevation ofa portable screen in inoperative IOSIIIOII and showing our new invention.

FIG. 2 is a rear elevation of the screen in fully extended and ocked position.

FIG. 3 is a rear elevation showing the screen fabric partially olled up in the case.

FIG. 4 is an enlarged perspective view of one end of the casmg with parts broken away.

FIG. 5 is a perspective view of the link or toggle joint with arts broken away.

FIG. 6 is a perspective view of the handle shown secured to he screen when the screen fabric is fully extended with parts hown in phantom.

FIG. 7 is an enlarged elevatiorial view of the stretch bar in My extended position and with the toggle in over the center osition, and with parts broken away.

FIG. 8 is a cross-sectional view taken on the line 8-8 of FIGv FIG. 9 is a cross-sectional view taken on the lines 99 of IO. 7.

FIG. 10 is a cross-sectional view taken on the line III-I0 of IO. 8.

FIG. 11 is a cross-sectional view taken on the line II-II of IG. 1.

FIG. 12 is an end view taken on the line l2-I2 ofFIG. 2. The screen casing 12 is the usual and customary one such as town in US. Pat. No. 259N585 issued Apr. 8, I952, to Du lais, having a spring roller on which the screen fabric I4 is ound. The free end of the fabric is anchored to a slat l6 and spring steel tensioning saddle 18 is anchored adjacent each id to the slat I6. Medial of the ends of the saddle I8 is the ma] bail 20. A hanging bracket 21 is secured to each closure ip 13. All the above is generally found in wall or ceiling ing-type screens on the market today.

The present invention is directed to the toggle-type bar to nsion the screen fabric and lock the spring roller from rther rotation, and the components associated therewith. The stretch bar comprises upper and

lower tubes

22 and 24. he upper end of tube 22 is enveloped in a short tube 26 (See G. 8) and both are pivotally and loosely anchored by means 'a bolt 28 to the usual center band 30 which is provided with l offset portion 32 to accommodate the head 34 of bolt 28 hich is welded to the center band.

The lower end of tube 24 is provided with an offset or goose :ck bar 36, rectangular in cross section, the upper end being lescoped interiorly of the lower portion of the tube 24 and reted thereto in fixed position. The bar 36, a shown in FIG. extends downwardly from tube 24 andsidewardly at about to the axis of the tube 24. The distal end portion 36' lies in a plane normal to the axis of tube 24 and is twisted about to a diamond-like shape (See FIG. 6).

A handle 38 is anchored to the distal end 36' of the bar 36 as clearly shown in FIGS. 6 and 9. In FIG. 6 it is to be noted that the upper surface of the handle is broad and flat for ease in operating the stretch bar. At 40 the surface of the handle is imprinted with the words "press to lock an at 42 the words press to release." the purpose of which will hereinafter be described.

It is to be especially noted that the handle 38 is provided with an integrally formed, rectangular in cross section, sleeve 44 of a size and shape to receive the free end of the bar 36'. The bar is inserted into the sleeve until it reaches the boss 46, and is held therein by a screw 48 which is anchored in an appropriate threaded aperture 50 in the bar portion 36'. Thus the handle 38 rotates 90 from the closed position of the screen (See FIG. I to the fully opened position of FIG. 2.

The bar 36 is provided with a cylindrical groove 37 into which the ball 20 is loosely seated to provide a pivot.

The two tubes 22-24 are loosely held together by a toggle or link 52, of U-shape cross section (See FIG. 10), which embraces the ends of the tubes as clearly shown in FIGS. 5, 7 and 8. A headed pin 54 extends loosely thru the

sidewalls

56 and 58 of the toggle 52 and thru appropriate aligned apertures 22' in the upper end 66 of the lower tube 24 to form a loose pivot. The upper end of toggle 52 as viewed in FIGS. 7 and 8 is provided with spaced apertures 59in wall 56 and complimentary apertures 60 in wall 58.

The lower end 64 of tube 22 (as viewed in FIG. 8) is pivotally secured to the link 52 by headed pin 54' extending thru appropriate apertures 60 in link 52 and offset apertures 24 adjacent end of tube 22. Each pin 54, 54' is retained in position by a speed nut 62. The numerous apertures in the walls 56-58 are of course for adjustment purposes of the

arms

22, 24 to compensate for production variations to increase or decrease the tension on the fabric that might be desired. Also, there may be variations in fabric length with time and usage. 7

Once the adjustment is made the

tubes

22, 24 and link 52 will extend to a fixed length each time they are extended.

It is to be especially noted that the apertures 22' and 24' adjacent the ends of

tubes

22 and 24 respectively, are positioned closer to one end wall then the other, while the apertures 59 60 in the sidewalls 56-58 are positioned substantially medially of the sidewalls 68 and 68' whereby the

ends

64 and 66 of tubes 22-24 will readily clear the inner surface of wall 68 when the tubes are moved from the position shown in FIG. I to that shown in FIG. 2.

As shown in FIG. 2 the toggle or link 52 and the tubes 22-24 extend downwardly from the pivot 28 and offset from the vertical axis extending between

pivot points

28 and 20. This is the result of the goose neck formation in bar 36.

In operation the screen casing is hung on a wall by any suitable means using the figure 8" shaped clip 70, or anchored to the ceiling by the clip 70 and chain 72. If the handle 38 is above reach the pull cord 74 may be employed.

By pulling downwardly on cord 74 or by the handle 38 the screen fabric 14 will be unwound from its roller. Further downward pull will position the screen fabric 14 and tubes 22-24 and toggle 52 in the position shown in FIG. 3. Further downward pressure is exerted on the handle at 40 until the tubes 22-24 and toggle joint 52 are offset from the vertical axis connecting the pivot points formed by bolt 28 and bail 20. This will now limit the downward pull of the screen fabric and forever prevent tearing the fabric 14 from its spring roller. Further the fabric is both properly tensioned and the spring roller locked in viewing position thus preventing further rota tion of the spring roller when the fabric is unrolled the desired length. Former tensioning devices for the screen fabric failed to provide means for preventing either over or under tension ing or the screen fabric. This had been solved by this invention for the first time.

raise the screen, slight pressure is exerted on the handle This will cause the toggle joint 52, as well as tubes 22 4. to move to the right (as shown in FIG, 3) in one moom that shown in FIGS. 2 and 7 and the spring roller will ake over and the entire fabric 14 will be rewound on the roller and move the tubes from the position shown in l and finally to that shown in FIG, 1. )l'dCl' to hold the tubes 22-24 in place behind the screen 12, a C-shaped clip 76 is secured to the saddle to autoally engage tube 24 just prior to the complete rewinding fabric 14 on its spring roller Without this clip 76 the t of the tubes 22-24 and link 52 would cause appreciadeward thrust on the saddle l8, tending to make the [4 roll up crookedly on its spring rollerv Thus the clip sports and retains the tubes 22-24 adjacent to the rear case [2 when the screen is not in use (See FIG. 1) o the wall 68 of the U-shape link 58 is provided with

do

68, 80 extending inwardly into the interior of the inside :e thereof to space the

tubes

22, 24 respectively away the inner face of wall 68, and retain the

tubes

22, 24 and 2 in a straight line when the screen fabric is fully ex d. Also upon closing the screen the over center apertures id 24' and pins 54, 54 through apertures 59 and the

dc

78 and 80 prevent the angle between the link 52 and the 24 from closing very little less than 90 during roll up of bile 14(See Fl(i. 3). is the present invention will allow the screen fabric to be raun, stretched and locked in one continuous move- The fabric l4 cannot be under or over stretched as is \lC with screens on the market,

claim; n a wall or ceiling hang-type portable projection screen a ng, a spring roller mounted in said housing, a screen mounted on and rolled up on said spring roller, a slat )I'Cd to the free end of said screen fabric, a saddle ted on said slat, and a bail mounted on the saddle medifthe ends of the slat; in combination with an automatic ming and stretch means for the screen fabric when in position and positioned on the rear of said housing, said comprising a pair of tubes pivotally joined together in intial endto-end relationship by a link joint, the free end a ofthe tubes pivotally secured to the rear of said casing, illy of the ends thereof, one end of a gooseneck bar ired to the free end of the other tube. the other end of ir being provided with a cylindrical groove to loosely and ally seat the bail and provide means to anchor a handle on, whereby when said screen fabric is withdrawn from ise the tubes and link will automatically move to a posi iffset from the vertical axis formed by the tube pivot on ising and bail slat to lock and tension the screen fabric, The device according to claim I wherein the two tubes ilded in substantially parallel spaced relationship behind .ousing when the screen fabric is positioned therein in in- LII operative position, and means on said saddle to retain said tubes in such position,

1 In a wall or ceiling hang-type portable projection screen having a case, carrying a spring roller for winding the screen fabric thereon, a slat for the free end of the fabric, a saddle mounted on said slat, having a bail positioned thereon medially of the ends of said saddle, in combination with a tensioning stretch and lock bar, said stretch bar comprising a pair of tubes, a short L -shaped link for pivotally securing said tubes together in substantially end to-end relationship, means on said case medially of the ends thereof pivotally securing the free end of one of said tubes to said case, offset means on the free end of said other tube pivotally securing said tube to said bail, a handle on the free end of said last-mentioned means for withdrawing said fabric from said case and moving said link and tubes in an offset position from the vertical when the fabric is withdrawn from said case, and returning said link and tubes in folded position behind said case when the fabric is rewound in the case, and hook means on said saddle to retain said tubes in folded position against said case when said fabric is rewound on said spring roller,

4 The device according to claim 3 wherein the means on the free end of said other tube is a rectangular in cross section bar anchored at one end to said other tube. and bent side weirdly and downwardly away from said tube, and terminating at right angles to said tube, a groove in said bar for pivotally retaining said bail, and the handle secured to the free end of iilld bar,

5. In a ceiling or wall hangtypc pro ection screen compris ing a case. a spring roller secured in said case, a screen fabric wound on said roller, a slat secured to the free end of said screen fabric, a saddle on said slat and a bail secured medially to said saddle; in combination with concealed stretch, tension and locking device mounted in the rear of said case. comprising a pair of tubes. a U shaped in cross section, toggle link pivotally securing said tubes together, a center band on said case positioned medially ofthe ends of said case and having an offset portion therein, the free end of one of said tubes pivotally secured to said offset portion of said case, a bar hav ing one end secured to the free end of said other tube and having a 45 bend substantially medially of its ends in a downwardly and sidcwiiidly tlltt'tlKIn, and beyond said bend said bar is bent at right angles and positioned in horizontal plane terminating beyond \itlt'l slin, a handle affixed to the tlltl of the free end of said bar, a cylindrical gioovi: in said bar or the loose reception t' f\lllt'l bul ti lorin ll illvitl 6. The device of claim 5 wherein the closed portion of said ll-shaped link is provided with inwardly extending detents adjacent each end of said link to space said tubes away from said closed wall of said link 7, The device of claim 6 wherein a clip is anchored to said saddle for supporting said tubes adjacent the rear of said case when in inoperative position

Claims

1. In a wall or ceiling hang-type portable projection screen a housing, a spring roller mounted in said housing, a screen fabric mounted on and rolled up on said spring roller, a slat anchored to the free end of said screen fabric, a saddle mounted on said slat, and a bail mounted on the saddle medially of the ends of the slat; in combination with an automatic tensioning and stretch means for the screen fabric when in open position and positioned on the rear of said housing, said means comprising a pair of tubes pivotally joined together in substantial end-to-end relationship by a link joint, the free end of one of the tubes pivotally secured to the rear of said casing, medially of the ends thereof, one end of a gooseneck bar anchored to the free end of the other tube, the other end of the bar being provided with a cylindrical groove to loosely and pivotally seat the bail and provide means to anchor a handle thereon, whereby when said screen fabric is withdrawn from the case the tubes and link will automatically move to a position offset from the vertical axis formed by the tube pivot on the casing and bail slat to lock and tension the screen fabric.

2. The device according to claim 1 wherein the two tubes are folded in substantially parallel sPaced relationship behind said housing when the screen fabric is positioned therein in inoperative position, and means on said saddle to retain said tubes in such position.

3. In a wall or ceiling hang-type portable projection screen having a case, carrying a spring roller for winding the screen fabric thereon, a slat for the free end of the fabric, a saddle mounted on said slat, having a bail positioned thereon medially of the ends of said saddle; in combination with a tensioning stretch and lock bar, said stretch bar comprising a pair of tubes, a short U-shaped link for pivotally securing said tubes together in substantially end-to-end relationship, means on said case medially of the ends thereof pivotally securing the free end of one of said tubes to said case, offset means on the free end of said other tube pivotally securing said tube to said bail, a handle on the free end of said last-mentioned means for withdrawing said fabric from said case and moving said link and tubes in an offset position from the vertical when the fabric is withdrawn from said case, and returning said link and tubes in folded position behind said case when the fabric is rewound in the case, and hook means on said saddle to retain said tubes in folded position against said case when said fabric is rewound on said spring roller.

4. The device according to claim 3 wherein the means on the free end of said other tube is a rectangular in cross section bar anchored at one end to said other tube, and bent sidewardly and downwardly away from said tube, and terminating at right angles to said tube, a groove in said bar for pivotally retaining said bail, and the handle secured to the free end of said bar.

5. In a ceiling or wall hang-type projection screen comprising a case, a spring roller secured in said case, a screen fabric wound on said roller, a slat secured to the free end of said screen fabric, a saddle on said slat and a bail secured medially to said saddle; in combination with concealed stretch, tension and locking device mounted in the rear of said case, comprising a pair of tubes, a U-shaped in cross section, toggle link pivotally securing said tubes together, a center band on said case positioned medially of the ends of said case and having an offset portion therein, the free end of one of said tubes pivotally secured to said offset portion of said case, a bar having one end secured to the free end of said other tube and having a 45* bend substantially medially of its ends in a downwardly and sidewardly direction, and beyond said bend said bar is bent at right angles and positioned in horizontal plane terminating beyond said slat, a handle affixed to the end of the free end of said bar, a cylindrical groove in said bar for the loose reception of said bail to form a pivot.

6. The device of claim 5 wherein the closed portion of said U-shaped link is provided with inwardly extending detents adjacent each end of said link to space said tubes away from said closed wall of said link.

7. The device of claim 6 wherein a clip is anchored to said saddle for supporting said tubes adjacent the rear of said case when in inoperative position.