US 2571382 A
Description (OCR text may contain errors)
Oct. 16, 1951 'A. L. RAVEN PROJECTION SCREEN SUPPORT 2 Sheets-Sheet 1 Filed Sept. 29, 1945 INVENTOR ALBERT L. RAVE/V I BY fwd 30 x 1 HIS ATTORNEYS Oct. 16, 1951 2,571,382
PROJECTION SCREEN SUPPORT Filed Sept. 29, 1945 2 Sheets-Sheet 2 INVENTOR ALBERT L. BA VEN HIS ATTORNEYS Patented Oct. 16, 1951 UNITED STATES PATENT OFFICE Claims.
This invention relates to projection screen stands or supports and more particularly to an improved construction of the sectional framework type of screen support for screens of large size frequently having dimensions as large as 18ft. by 24 ft.
With the sectional type of projection screen supports heretofore used outdoors, for example for military or naval instruction and entertainment programs, difiiculty has been experienced because of grit andsand particles lodging in or adhering to the joint structures between the sections of the framework. The presence of such particles in these joints causes jamming and renders it most difficult either to set up or take down the framework. The prime object of the present inventionis to provide a sectional screen supporting framework which is so constructed as to eliminate this trouble.
Difiiculty has also been experienced with the outdoor type of screen supporting stand as heretofore ,constructedbecause of their large number of separate parts and the consequent danger of loss in stowing ortransport, as well as complication of the setting .up and take-down processes. Afurther object of the invention is to provide a construction of sectional screen support for holding the screen stretched in operative condition in which the number of parts is greatly reduced, thereby overcoming such difficulties.
.A still further object of the invention is to provide ,a sectional screen support construction in which the mountingand dismounting of the projection screen .on the support is rendered easier and more quickly accomplished than heretofore.
. The invention will be understood from examination of the accompanying drawings showing one embodiment thereof by way of example and taken together with the following description. In h s drawings:
Fig. 1 is a .view inside elevationof the improved Screen supporting-stand or framework set up and witha projection screen mounted in place thereon;
Fig. 2 is .an.,enlarged cross-sectional view of a typical joint taken .on any of the lines .22 of Figs. 1, 3, or 4 Fig. 3 is .a view, also drawn to an enlarged scale, of the lower portion of the screen stand shown in Fig. 1, looking from the right of that fi ure, partly in s e e e at on and partly in sectionon the line "3T3 of that figure;
ig- .4 .ai egmentary vi w cor sponding to th l wer rieh ran cerne efj a drawn to .2 about the same scale as Fig. 3 and with parts shown in section;
Fig. 5 is a side view of the preferred form of sectional side unitof which the supporting framework shown in Fig. lmay be constructed;
Fi 6 is a view similar to Fig. 5 of a modified form of side unit;
Fig. 7 is a view partly in section of a sectional unit connector;
Fig. 8 is an end view of the connector shown in Fig. 7;
Fig. 9 is a view of a combined corner and upright side unit;
Fig. 10 is a View similar to Fig. '7 of a form of connector used with the sectional unit of Fig. 5 and Fig. 11 .is a cross-sectional view .of a detail taken .on line I.ll I .of Fig. 4.
Referring now to these drawings, the supportin fram w r ind a e generally b numeral l in Fig. 1 arranged to stretch the projection screen ,2. between the upper and lowerhorizontal side membersand the two upright side members of the frame, so .that the screen is held flat without wrinkles. In order to support framework l at a suitable distance from the ground it is provided at each end, that is at the oppositesides of screen 2, with standards indicated generally by numeral 3 having two spreadin legs .held at right angles to the .surface of the screen, thus giving the structure stability.
The rectangular portion of the supporting framework .shown in Fig. 1 is made up of the sectional units shown in ,detail in Figs. 5 to 10 inclusive. Thus the upright side portions each comprise two units ,4 of. a corner type shown in Fig. 9 joined together by two connector units 5 of the type shown Fig. 7. The top horizontal portion of the rectangular framework is made up of four side units .6 shown in Fig. 5 with .a single connector unit v l (Fig. 10) at its center. The bottom,horizontalportion is assembledwith a modified form of side unit ,8 illustrated in Fig. 6, three of these units being used andconnected together by means of two of the connector units 5 (Fig. 7.).
It will be understood thatin practice both the top and bottom horizontal side portions of the rectangular framework structure are made-up of only one type of sectional side unit, that is to say, of either the preferred form of side unit 6 and connectors l or of the modified form of side unit 8 withconnectors 5, instead of makin up the bottom portion with units 6 and the top portion with units 5, as has been shown in Fig. 1 for simplicity of illustration.
The basis of construction of this framework is the assembly of a plurality of sectional members each having a circular opening at one end and a polygonal projection at the other adapted to be telescoped into the opening of an adjacent member. Thus, for example, the sectional side unit 6 (Fig. comprises a suitable length of circular tubing 9 having an internal circular opening or bore In at its right-hand end and a polygonal projection II at its left-hand end. Tubing 9 may be made of steel or any other suitable material which possesses the required degree of strength as well as lightness of weight, alumi num or magnesium alloy being preferred.
Polygonal projection II may be triangular, square, or have any-suitable number of flattened sides. As shown in the drawings this projection consists of a short length of hexagonal tubing (also preferably of aluminum) permanently fixed in the end of tubing 9 as, for example, by means of a through bolt or pin I2. The principal requirement of projection II is that its outside diameter across the corners shall be such as to permit it to fit snugly within the right-hand end bore ID of a similar unit 6, or other member of the framework structure having a similar circular opening. This fit should be such as to permit the two parts to be telescoped together or separated by hand.
As sho n in Fig. 2 the interior surface of the right-hand end of opening ID of an adjacent sectional unit or other frame member of the supporting framework fits snugly against the corners of the hexagonal projection II, and the length of this projection (for example about 4 to 6 inches) is sufiicient to rigidly connect the two members. The engagement of the hexagonal projection II and interior surface of the tube is along the six linear regions of contact at the corners, and should grit, sand. or the like, become lodged in or adhere to either of the interfitted members. the operation of telescoping the two members to ether will displace such particles from the linear regions of contact into the spaces I3 which occur between adjacent corners of the poly onal pro ection and the interior circular surface of the tube.
In order to lock the two inter-fitted members together the polygonal plug II of unit 6 is provided with a re iliently mounted pin or buttton I4 which proiects through a small hole in one of the fiat sides of the hexagonal plug and is adapted to be received in a similar hole I5 provided in the wall of circular bore Ill. This is shown in detail in Fig. 4 where corner unit 4 is provided with one of the polygonal plug members I I as will be described later. Button or pin I4 is riveted or welded at the center of an arched spring member I6 having two equal legs H, the outer ends of which bear against the inner surface of the hexagonal projection.
This assembly of pin and spring, when once forced into the interior of projection II and the pin received in the opening through one of the flat walls of this member, is for all intents and purposes permanently fastened in place. Should it become broken or damaged, however, such assembly can be easily replaced with a new one.
Completing the description of the sectional unit 6, there are permanently mounted upon this unit a plurality of screen attaching devices indicated generally by numeral I8. These each comprise a helical sprint. I9, normally closed,
having an integral loop '20 which loosely encircles tubing 9 of the unit. The opposite end of helical spring I9 terminates in a combined hook 2| and finger loop 01' pull ring 22 which is preferably pivoted, as shown at 23 in Fig. 4, to the end of spring I9. This permits hook members 2I to be folded parallel with the unit tubing which facilitates stowing the units in compact bundles for storage or transportation.
The finger loops or pull rings 22 afford a convenient means for manipulating hooks 2! into engagement with grommets 24 which are provided in suitably spaced relation throughout the perimeter of screen 2. While loops 20 slide freely along the surface of tubing 9 so that the attaching devices I8 may accommodate themselves to changing positions of grommets 24 caused by shrinkage and expansion under changes in atmospheric conditions, nevertheless loops 20 fit the surface of tubing 9 snugly enough so that they are permanently held on the unit by means of protuberances such as the heads 25 of the bolt or pin I2 which secures the projection I I in place, and such as the heads of a second through pin 26 placed at the right-hand end of unit 6 for this purpose. .However, should any of the attaching members I8 become damaged or broken they can readily be replaced inasmuch as loops 20 are constructed as spring loops. They can be forced over the bolt heads 25 or screwed past them as in removing a key from a coil type key ring.
Corner units 4 are constructed of a bracket 21 which can conveniently be made in the form of a casting with two legs 28 at right angles to each other and preferably strengthened by a brace portion 30. Leg portion 28 has an opening extending part way through it into which one of the polygonal projections II is secured, for example, by means of a through bolt 3 I. The opening through the other leg portion 29 is circular and large enough to receive a circular tube 32 which is permanently secured within it in any suitable manner. This opening and tube 32 extend entirely through leg portion 29, for a reason which will presently appear.
Tube 32 may have any suitable length but its length is preferably such that two of these corner members 4 when connected together by means of a single connector 5, as shown in Fig. 1, will correspond with the height of the screen 2. The length of connector unit 5 may be varied to give the desired height to the upright portions of the framework. For extra large screens a side unit 6 may be added to connector 5. It will be understood that the opposite end of tube 32 has a circular bore ID adapted to receive one of the polygonal projections I I of connector 5 and for this purpose is provided with a locking hole I5 for receiving one of the locking pins I4 on the connector.
Connector 5 itself comprises a section of polygonal tubing at the center of which is fixed a short encircling sleeve 33 of circular tubing of the same diameter as sectional units 4 and 6. This sleeve may be permanently fixed in position by means of a pair of pins 34, as shown in Fig. '7. The length of sleeve 33 usually is just sufiicient to serve as a connector between two sectional units but may be varied to change the length of the connector.
The top horizontal side of the supporting framework shown in Fig. 1 is made up of four of the side units 6 (Fig. 5), the two units adjacent the center having their polygonal projece tions II facing one another and inter-connected by =means of aconnector (-Fig. 10) "This connector comprisesmerely'a short lengthof circular tubing 35, just a little longer than the combined lengths of the two projections II and provided near each end with one of the pinholes 15 for receiving the locking pins 14 of projections II.
The bottom side porticn of the screen supporting framework'of Fig. 1 is shown as being made up of three ofthe side units :8 (Fig.6). These units are similar to connector I but are of suitable length tobe-employed as aside unit instead of a connector. That is to say, side unit 8 consists'ofa length of tubing '36 of-comparable length "'totubingflpf unit-'6' and having circular openings in at each end -to receive polygonal projections H and provided-with pin-holes 1-5 for these locking pins. Permanently mounted on tubing '36 are a plurality of the screen attaching devices l8 which are held thereon by means of two pins '26 having rounded heads 25 at each end.
As previously mentioned, it will be understood that in practice both the top and bottom side portions of the screen supporting framework of Fig. l are made of only one type of side unit instead of making up the bottom section with units 6 and top section with units 5.
The rectangular sectional framework described above is mounted and held in upright position by means of the standards 3 (Figs. 1 and 3). These each comprise a three-forked bracket 31 which may conveniently be made in the form of a casting having two downwardly directed extensions 38 preferably arranged at about right angles to each other as shown in Fig. 3, and a single upward extension 39. Extensions 38 each have permanently secured therein one of the hexagonal projections II with their locking pins l4. Onto each of these projections ll may be telescoped a leg member 40 of any suitable length consisting of an appropriate length of tubing of circular section and of the same diameter as the tubing 9, 32, or 36 used for the other parts of the sectional framework. Legs All may be provided with plug 4! at their lower ends to serve as feet.
The upward extension 39 of each of the standards 3 has permanently fixed to it an elongated polygonal tubular projection 42 similar to projection l l in size, but of such a length as to telescope for some distance, some three or four feet, into the interior of tubular member 39 of the corner units 4 when the framework is supporting the screen 2 at the minimum distance from the surface of the ground. This enables the height of the screen as a whole to be adjusted with respect to the ground in order to elevate it to the proper height so that it can be seen to the best advantage. The framework is held in adjusted position by means of thumb screws 43 which are threaded through the walls of both leg portion 29 and tubular member 32 of each of the units 4. These thumb screws 43 in the two units 4 at the top corners of the framework will be idle but the corner units are all made alike so as to prevent confusion.
It will be understood that the spacing of the grommets 2 of screen 2 may be made to suit differing conditions and that the top and bottom side units 5 and 8 may be provided with any suitable number of screen attaching devices [8; also that connectors 5 and I may have one or more of these devices. As shown in the drawings, each of units 6 and 8 has three such devices but either a greater or lesser number may be used as desired. Even if some particular screen 2 which it is desired to mount on the screen support has a greater or less number of grommets than there are-attaching devices, 'thisis not important since any-attaching devices 18 not in use will not interfere with the :proper stretching of the screen.
In order to stretch the cornersof screen! and hold them Lfla't, either a tie cord 44 or aspring attaching device l8 may be used between the corner grommets and brace members '30 of the 'corner'units 4, the former being shown in Fig. 4. A spring friction clip '45 may be used tosecure the ends of this cord together.
The adjustable framework of the present invention, while having its principal utility as a support for projection screens, is Well adapted to support and display various sheet-like articles such as maps, backgrounds and the like. Accordingly the term projection screens as used :in the appended claims is intended to include such other :articles.
It will be understood that this inventionisnot limited to the particular forms of construction illustrated in the accompanying drawings but that other forms may be devised to accomplish the objects of the invention without departingfrom the spirit -thereof,.and that its scope is therefore intended to be set forth in the following claims.
1. In a support for projection screens having a sectional framework to hold the screen in stretched condition, a pair of tubular framework members, one having a polygonal axial projection having relatively sharp corners at one end and the other having a cylindrical internal bore adapted to telescope onto said projection to support said members the one by the other, whereby the polygonal axial projection makes only substantially linea1 contact with the surface defining the circular bore.
2. In a support for projection screens having a sectional framework to hold the screen in stretched condition, a pair of tubular framework members, one having a polygonal axial projection at one end having relatively sharp corners and the other having a cylindrical internal bore adapted to telescope onto said projection to support said members the one by the other, whereby the polygonal axial projection makes only substantially lineal contact with the surface defining the circular bore and means fixed to one of said members for releasably locking said telescoped members one to another to prevent relative longitudinal displacement.
3. In a support for projection screens having a sectional framework to hold the screen in stretched condition, a framework section comprising a, tubular member having at one end a polygonal axial projection having relatively sharp corners and at the other a cylindrical bore having a diameter only slightly smaller than the diameter of the circle which will just circumscribe the polygonal projection, whereby the polygonal projection may be inserted into the cylindrical bore of a, like member and when so inserted, the contact between the projection and the surface defining the bore will be substantial- 1y lineal.
4. In a support for projection screens having a sectional framework to hold the screen in stretched condition, a pair of framework members, one having a polygonal axial projection at one end having relatively sharp corners and the other having a cylindrical internal bore adapted to telescope onto said projection to support said members the one by the other, whereby the polygonal axial projection makes only substantial- 1y lineal contact with the surface defining the cylindrical internal bore of the other member, and means carried by the polygonal projection for releasably locking said telescoped members to one another to prevent relative longitudinal displacement, said releasable locking means including a bowed leaf spring having the end portions thereof slidably resting on one inner side of the polygonal member and a latching pin carried by a midpoint of the bowed spring and extending through aligned openings in the opposite side of the polygonal member and the wall defining the circular bore.
5. In a sectional framework for supporting projection screens, a framework section comprising a corner unit including a bracket having two extensions at right angles to one another, each extension having a bore extending from its distal end, a, tubular member having one end permanently secured within the bore of one of said extensions, the other end of said tubular member extending beyond said one of the extensions and having a circular bore extending axially therefrom to receive a framework member, and a member permanently secured within the bore of the other extension and having a polygonal portion having relatively sharp corners extending beyond said other extension adapted to have a tubular member telescoped onto it and to make only substantially lineal contact therewith.
ALBERT L. RAVEN.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,099,959 Wylie June 16, 1914 1,379,064 Welsch May 24, 1921 1,461,441 Davis July 10, 1923 1,844,410 Schalk Feb. 9, 1932 1,965,644 Heffelflnger July 10, 1934 1,983,612 Junkers Dec. 11, 1934 2,249,031 Neely July 15, 1941 2,350,582 Booth June 6, 1944 2,357,819 Greer Sept. 12, 1944 2,403,661 Hurley July 9, 1946 2,408,852 Holman Oct. 8, 1946