US2534960A - Foldable frame for screens - Google Patents

Description

Dec 19, F550 A. v. DITTY FOLDABLE FRAME FOR SCREENS 2 Sheets-Sheet 2 Filed May 26, 1945 iii (Ittornegs I Patented Dec. 19, 1950 Allan V..-Ditty,-'Grosse Pointe, Mich., assignor, by mesne,-assignments, to Arthur J Bradford, Chicago, .Ill.

Application-Ma'y -26, 1945,:Serial 16055965023 ZCIaims. 1

This. invention relatesto collapsiblescreens; and particularly to a'rfoldablevframe =for projection screens for use with optical projection appa- 'ratus.

One object of this invention is to :providea col- :lapsiblescreen with ;a foldableframe havingan extensible and collapsible support, the ;opposite portions of .which. aremechanically synchronized so as to be extended and :retracted in unison.

Another object is to provide =a.foldable.'frame for a screen supported by ,pivoteid .arms which are, mechanically interconnected bya mechanism which positively guaranteesitheir beinggextended and retracted in synchronism.

,An'other obie-ctqis to provide a-gioldable frame for a screen zasset forth.inlthejpreceding :ohject 'Whereinmeans-is provided by @the samemechanism for holding the arms in theirrextended positions without danger of accidental collapse.

Another object is to provide a :fold-ableframe iorca screeny-having a flexible. sheet capable of being wound upon a roller and 'ha-Vinga supporting-bar along one edge connected .topivoted arms which aremechanically interconnected to 'be ,extended :and retracted in unison.

.Anot-her objectis to provide a 'foldable frame for :a screen asset. forth. in j-the preceding object whereinrtheerms and bar are. adapted to hereceived in the housing whichwcontains the. roller.

.In the drawings:

jFigurel is a rear elevation of apreferred embodiment of the -oollapsibleaframe for a screen of the ipresentinvention, with'a .portion of the housing broken away to expose thellower'en'ds of the supporting arms, and with "the screen .extended.

.Figure 2 is a right-handside elevation of the screen shown in Figure 11.

Figure 3:is.a rear elevation similar to Figure 1, :but with thescreen retracted and collapsed.

Figure 4 is a horizontalsection through the screen of-Figure 1 takenaalongthe line '44 therem.

Figure '5 is a fragmentary .vertical: longitudinal sectionthrough the housing WiththescreenQeX- tended, taken along the :broken line 5-15; in. Figure 4.

Figure 6 -is a verticalcross-section through-the screen housing with the screen extended, taken along'the line :6-6 in Figure 1.

.Figure'? is a cross section similarto. Figure-6, but with the screen retracted .into its housing.

Figure 8 is aleft-hand end elevation r-of the screen housing of Figure 1 with the screen -extended.

Figure 9 (-is a horizontal section through the pivotal connection of' the supporting arms, taken :along the line 99,in Figure 1.

Fi ure :10 is-a vertical section through the-piv- =otal;'connection -of;one set of the sup orting arm-s takenalong-the line !.!-l6 in/Figure :2.

In eneral, the -invention consists of 1a flexible sheet member WhiGhjiS wound 1upon ,a'-r.0 11er in a yhousing. The sheet member is ;;provided with a supporting bar a'longyi-ts upper oriree edge. To this {bar aregsecured :a pair of ydownwardly ;ex-- tendinglarms .pivotally connected ;to the :upper ends ofyagpa'ir of upwardly extendingarms :piv- =ot'a1ly mounted on a bracket-in the; screen housing. The upper ends. .ofs-the IAPDBIJfll-IIlSfflIld the :lower. ends of.a:the lower arms'are interconnected by toothed gearing in such a manner that the two sets. of arms will be extendedand retracted in unison. When retracted, the "pivoted a'rm's told-downward into the housingas the screen is wound up on="the roller, a-nd the bar comes down onftop of the housing.

Hitherto, it has been difficult to provide -a collapsible screenwherein the opposite ends-0f the screen'proper would always be eXtendedto-the 'samepositions; thereby preventing wrinkles; and also wherein the extended sc'reenwould, he rigid- 1y supported without sagging and yet would be capable of instant retractionin'to a small housing. "The screen of the present invention-overcomes theseprevious .difiiculties, and solves the problem by providing apair of sets of pivoted arms which arejgeared together torise andffalll in unison. 7

Referring-to ,thewidrawings in detail, Figure l shows apre'ferred embodiment of .theffoldable Jframefor a screen havinga 'boxelike housing generally .designated le with; a screen member generally designated] 1 v capable of being wound upon a roller, generally designated-l-2 andsustained in its extendedposition by a supporting vstr ucture generally. designated I3.

Thehousing Ill is inthe form of abox having abottom 14,.front and reariwalls. l5land N; (Fig-- ures 6 and 7)., a toplland ends. Band H). The ends 18 and 19 are provided with apertures 20 fromwhich tubular bracketsZl and 22 extend inwardly-and are secured by rivets 23-to the ends t8 ,and. I9. lbebracketZ-i is provided with an -elongated holefland the bracket 22 with .a circular hole 2 5.

Theholes 2-4 andf25 receive thecorrespondingly shaped-end pins 2-6 and-21 respectively (Figure ,-5)

r of the roller. The pin 2 'l of circular GI'QSS? edges 58 of the channel arms 52.

section is inserted directly in the end cap 28 at one end of the roller whereas the pin 26 of elongated cross-section is at the end of a shaft 29 passing loosely through a bore 30 through the other end cap 3| and havin an enlarged head 32 engaging an enlargement 33 at the end of the bore 30. The shaft 29 at its inner end is provided with a head 34 having a socket 35 for receiving the inner end of a spiral spring 36, which encircles the shaft 29 and has its opposite end secured in a socket 3'! in the end cap 3|. The end caps 28 and 3| are interconnected by a hollow tubular roller barrel 38 rigidly secured thereto as at 39.

The roller barrel 38 is provided. with a longi tudinal groove 46 (Figure 6 and '1 within which is anchored the inner edge 41 of the screen member H, as by the retaining bar 42 secured to the roller barrel 38 as at 43. The opposite edge of the screen member-H is wound around a tubular cross-bar 44 and secured to itself as at '45 (Figure '7) by a suitable adhesive or other means. Secured as at 46 to the center of the tubular cross-bar 44 is a bracket 4'5 which extends over the top of the cross-arm 44 and has a downwardly extending arm 48 forming a plate with apertures 49 (Figure '7) for receiving a pair of threaded studs 50. These studs 56 pass through apertures 5| in a pair of upper channel arms 52 forming the upper portions of the supporting structure [3. Each stud within the channel portion of the channel arm 52 carries a quadrant gear 53 meshing with the quadrant gear 53 on the other stud 56 (Figure 1). The quadrant gears 53 are firmly secured to the channel arms 52 by the pins 54 passing through both.

The channel arms 52 are pivoted to the lower arms 55 by means of pivot pins 56 passing through apertures 51 in each pair (Figure 10). The channels in the channel arms 52 face inwardly toward one another, and the pivot pin holes 5'? are so arranged that when the screen is extended to its fully raised position, the lower arms 55 move past the position of alignment with the channel arms 52 and come to rest against the lower back In this way the pivoted arms 52 and 55 are moved past dead center into self-sustaining positions.

The lower ends of the lower arms 55 are provided with bores 55 (Figure 6) for receiving a stud bolt 60 passing therethrough and through an aperture 5! in an angle bracket 62 secured as at 53 to the bottom E4 of the housing ill. The stud bolt 60 also passes through the side wall E6 of the housing I D and is provided with lock nuts 64 and 65 on opposite sides thereof. Mounted on the stud bolt 86 and secured as at 66 to the lower arms 55 are two meshing gears 61 which operate in a similar manner to the quadrant gears 53 described above (Figure 5).

In operation, to extend the screen from its folded position of Figure 3 the operator pulls 'upward on the tubular cross-bar 44 of the bracket 41, causing the upper and lower arms 52 and 55 to move from the position of Figure 3 upwardly into the positions of Figure l, meanwhile crossing the aligned position just prior to halting with each lower arm 55 coming to rest against the back lower edge 58 of each channel arm 52. As the arms 52 and 55 swing upwardly and their pivots 56 swing in arcs from the outer ends of the casing l0 (Figure 3) to the central positions of Fig. 1, the intermeshing teeth of the gears 53 and 61 drivingly interconnect the two 4 sets of arms 52 and 55 in such a manner that the arms move in unison.

Since the pivots 5D, 56 and 60 are spaced laterally from each other, the cross bar 44 is supported, in effect, by a pair of rigid but foldable spaced pillars. The geared interconnection of the two sets of arms 52 and 55 prevents one set of arms from moving independently of the other set, hence the cross-bar 44 is raised and lowered by a linkage which causes it to move through successively parallel positions. As the screen member I l is raised and unwound from the roller i2, the coil spring 36 (Figure 5) is wound up and stores up energy. This maintains the screen member II in a taut position. The screen member I l is preferably made of a resilient material, such as white rubber, so that it is free from wrinkles and maintains itself in that condition.

To lower the screen member II, the operator grasps the supporting structure l3 adjacent the pivots 56 and pushes the latter away from each other. The pivots 56 and arms 52 and 55 then move past their aligned position and downwardly into the folded position shown in Figure 3. Here again the intermeshing gears 53 and 61 cause the arms 52 and 55 to move downwardly in synchronism, causing the cross-bar 44 to move downwardly through successive parallel positions. The cross-bar 44 comes to rest immediately over the slot 68 in the top I! of the housing ill, partially closing this slot. The screen is thus foldable into very compact form and is protected by the housing It against dust and damage.

While a specific embodiment of the invention has been described and illustrated, it will be understood that various modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

What I claim is:

l. A foldablevframe for a collapsible screen comprising a base, a cross bar spaced above said base, and two pairs of foldable uprights arranged adjacent one another and having their lower and upper ends pivotally connected to the central portions of said base and cross bar respectively, each of said uprights including a lower and an upper arm having a common pivotal connection to one another and disposed alongside one another in the folded position of said arms, said common pivot lying substantially at the outer extremity thereof, one of said arms having an extension overlapping the other arm beyond said common pivot and having an abutment engageable with said other arm at a location spaced away from said common pivot when said arms are extended, said common pivot and said abutment being disposed inwardly of a line joining the centers of the pivotal connections of the upright with the base and cross bar respectively when said frame is fully extended, thereby rendering said frame self-sustaining in its fully extended position.

2. A foldable frame for a collapsible screen comprising a base, a cross bar spaced above said base, and two pairs of foldable uprights arranged adjacent one another and having their lower end and upper ends pivotally connected to the central portions of said base and cross bar respectively, each of said uprights including a lower arm and an upper arm having a common pivotal connection to one another, one of said arms being of channel cross-section and the other arm being received within the channel portion thereof in the folded position of said arms, said common pivot lying substantially at the outer extremity 2,534,960 5 6 thereof, one of said arms having an extension REFERENCES CITED overlapping the other arm beyond said common The following references are of record in the pivot and having an abutment engageable with file of this patent: said other arm at a location spaced away from said common pivot when said arms are extended, 5 UNITED STATES PATENTS said common pivot and said abutment being (115- Number Name Date posed inwardly of a line joining the centers of 1,116,562 Calmes Nov. 10, 1914 the pivotal connections of the upright with the 1,820,739 Heck Aug. 25, 1931 base and cross bar respectively when said frame 1,915,944 Nagel June 27, 1933 is fully extended, thereby rendering said frame 10 1,946,639 Ridden Feb. 13, 1934 self-sustaining in its fully extended position. 1,981,444 Wittel Nov. 20, 1934 ALLAN V. DITTY.

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