US2899735A

US2899735A - Wall molding forms for making a reinforced concrete wall

Info

Publication number: US2899735A
Authority: US
Publication date: 1959-08-18
Anticipated expiration: 1976-08-18

Description

Au 18, 1959 L; GRAEF 2,899,735

WALL MOLDING FORMS FOR MAKING A REINFORCED CONCRETE WALL Filed Jan. 24, 1955 4 Sheets-Sheet l INVENTOR. g Eowmzo L. G/eflEF HTTOBNE YS Aug. 18, 1959 E, L, GRAEF 2,899,735

WALL MOLDING FORMS FOR MAKING A REINFORCED CONCRETE WALL- Filed Jan. 24,- 1955 r C 4 Sheets-Sheet 2 Al I v 46 54- .615 a e2 52 j y 66 62 W P p/Cm) I @q INVENTOR. [own/e0 L. GR/IEF HT roe/1E YS E. L. GRAEF Aug. 18, 1959 WALL MOLDING FORMS FOR MAKING A REINFORCED'CONCRETE WALL Filed Jan. 24, 1955 4 Sheets-Sheet 3 INVENTOR. fawn/e0 LCEHEF ,4 r TOBHEYS Aug 18, 1959 GRAEF 2,899,735

WALL MOLDING FORMS FOR MAKING A REINFORCED CONCRETE WALL Filed Jan. '24, 1955 4 Sheets-Sheet 4 INVENTOR.

fowmeo L. GAE/45F v Wrn/ HTTOB/YEYS United States Patent WALL MOLDING FORMS FOR MAKING A REINFORCED CONCRETE WALL Edward L. Graef, Seattle, Wash.

Application January 24, 1955, Serial No. 483,613

6 Claims. (Cl. 25-131) This invention relates to improvements in means for the making of reinforced concrete walls by the operation of placing the fluid concrete mixture into forms in which the reinforcing elements are contained, allowing the mixture to set and then removing the forms from the concrete walls. More particularly, the invention has reference to the utilization of secured reinforcing elements for the support and alignment of the enclosing forms during the Wall forming operation and in the whole providing a form construction that is readily adjustable to the dimensional requirements of the completed structure.

It is one of the principal objects of this invention to provide a novel, practical and economical means for the anchoring, supporting and aligning of the reinforcing elements of the wall, and in the utilization of the anchored and secured elements as the means of support for the enclosing fonns. Furthermore, to provide means for the application of a desired prestressing tension to the reinforcing elements, and for the holding of the elements under the tension as applied by the supporting and aligning means until the concrete has set.

It is also an object of the invention to provide enclosing walls of novel construction for opposite sides of the form; each wall involving a novel overlapping arrangement of corrugated or ribbed nestable sheet metal plates, or sections, which are held in their functional overlapped relationship, and the opposite form Walls accurately spaced from each other, through the use of cross-ties of novel kind which are anchored to the reinforcing elements for support of the forms.

Another object of the invention resides in the utilization of extendable jacks or struts of novel kind for the support and alignment of the reinforcing and walls which constitute the enclosing forms, and in those details of construction of the metal plates, the cross-ties and the wall supporting wales that make possible the locking together of the overlapped edge portions of the assembled metal plates byuse of the opposite end portions of the cross ties. Furthermore, in the utilization of the crossties as the means for the functional support of form bracing wales that are applied along the outsides of the form walls which comprise the enclosing forms normal to the ribs or corrugations therein.

It is a further object of this invention to utilize a concrete wall reinforcing material made in the form of a wire mesh curtain; this curtain being adapted to be attached along its lower edge to a special form of anchoring means that is embedded in the footing or foundation on which the concrete wall is to be built, and to be attached along its upper edge to means through which Patented Aug. 18, 1959 the application of prestressing tension may be applied to the curtain, and the curtain so held and secured under such tension as to give it the rigidity that adapts it for use as the means of alignment and support for the Walls of the enclosing form.

Another object of the invention is to provide wire cross-ties of novel form for use with a reinforcing curtain of the above character, that may be so applied to the crossed wires of the curtain, as to avoid pulling them apart, and which cross-ties are equipped adjacent their opposite ends with accurately spaced stops against which the opposite sidewalls of the enclosing form will be engaged to establish their spaced relationship, and which terminate at their ends in loops adapted to be projected through registering slots in the overlapped edges of the sheet metal plates comprising the form walls and into openings in the wall bracing Wales to receive wedge pins therethrough for the functional seourement of the wales, and to establish the proper spacing of the form Wallis relative to the reinforcing curtain and to each 0 er.

Yet another object of the invention resides in the provision of a novel means for applying the desired prestressing tension to the reinforcing curtain; this means being characterized by novel bracket means of support designed to rest upon the footing to which the reinforcing is anchored, and a series of paired jack equipped struts arranged along and at opposite sides of the curtain upon said brackets and in convergence, for the application of the curtain prestressing force through the mediacy of grapple beams that are extended along and attached to the upper edge of the curtain; the jack of each pair of struts being relatively adjustable to effect controlled lateral adjustments of the curtain as may be required for its accurate alignment.

Still further objects of the invention reside in the dey tails 'of construction and combination of parts involved or embodied in the forms, as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I have provided the improved details of con struction, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is a side view, or elevation, of a section of a form as set up for the making of a concrete wall; certain parts of the form being broken away for better illustration of the reinforcing curtain.

Fig. 2 is a horizontal section of the form structure taken on line 2-2 in Fig. 1.

Fig. 3 is an enlarged plan view of a form, with parts broken away to reduce the size of the view, particularly showing the cross-ties whereby the opposite sidewalls of the enclosing forms are anchored to the reinforcing curtain and held in a definite spaced relationship.

Fig. 4 is a vertical section taken on line 4-4 in Fig. 1, particularly illustrating the arrangement of paired reinforcing curtain tensioning jacks at opposite sides of the wall.

Fig. 5 is a perspective view of the curtain anchoring means to be applied to the footing and indicating, in "dotted lines, the application of the lower edge of the reinforcing curtain thereto.

Fig. 6 is an enlarged, perspective detail showing hooks as formed on the anchoring means to which the lower edge of the reinforcing curtain is attached.

Fig. 6a is a perspective view showing a part of an anchoring means of an alternative form.

Fig. 7 is a view showing the reinforcing anchoring means as applied to a positioning support preparatory to its being embedded in a footing.

Fig. 7a is a sectional detail showing the hooks of the curtain anchoring means exposed in the channel formed in the footing by the positioning support; the channel serving as a key to receive the wall forming concrete.

Fig. 8 is a vertical cross-section through a part of a form, showing bracing wales as applied against form walls, and as secured against the stops by wedge pins applied to the loops at one end of a cross-tie.

Fig. 9 is a perspective view of one of the cross-ties, as applied in use to crossed wires of the reinforcing curtain.

Fig. 10 is a perspective View of a portion of a grid yoke or beam as designed for attachment to the upper edge of the reinforcing curtain for use in the prestressing, alignment and securement of the curtain.

Fig. 11 is a perspective view of a bracket as designed for application to a footing for support thereon of a prestressing strut.

Fig. 12 is a detail, in perspective, of a closure for joining a sidewall of the enclosing form with a soffit sheet.

Fig. 13 is a sectional view showing another form of tie as applied to overlapped wall plates.

Fig. 14 is an enlarged sectional View of the adjusting means for a form supporting strut or jack.

Referring more in detail to the drawings:

The present invention contemplates the use of wall reinforcing material of wire mesh form and it is most practical that the wires thereof extend horizontally and vertically and that they be evenly spaced. Such a reinforcing element is designated in its entirety in the drawings by numeral 10, and it will hereinafter be referred to as the reinforcing curtain. It has further been found most practical in the present invention, that all vertical wires of the reinforcing curtain be parallel and shall cross the horizontal wires at the same side of the curtain, as has been shown in Figs. 3 and 4. The invention is characterized further by the fact that preparatory to the building of the enclosing form to receive the concrete, the reinforcing curtain 10 is anchored along its lower edge to a foundation or footing on which the concrete wall is to be erected, and is then placed and held by means attached thereto along its upper edge under such prestressing tension that it is rendered adequately rigid for use as a means for support and alignment of the enclosing form walls and to control temperature cracks in the completed concrete wall.

For the purpose of anchoring the reinforcing curtain to a footing, I now prefer to employ means such as that shown in Figs. 4, 5, 6 and 7 wherein 12 designates a foundation or footing suitable for the building of a concrete wall thereon. This may be formed in the usual way by the placing of concrete between previously placed forms, 13-13, as shown in Fig. 7. After the form members 1313 have been placed in position to receive the concrete, but before the concrete has been poured, I dispose a reinforcement curtain anchoring means 14, as shown in Fig. 5, in position for being partially embedded therein. The anchoring means 14, comprises a wire of suitable gauge for this purpose, that is bent in zigzag manner to provide a succession of V-shaped portions 14x of the same size and all in the same vertical plane. Across the medial portions of'these V-shaped portions, a continuous wire 15 is applied and welded. The joining end portions of the adjacent legs of the V-shaped parts of this anchoring means are bent laterally and downwardly, each to provide two spaced and downwardly facing hooks 16-16, as seen in Fig. 6. These two hook forming portions are joined by a diagonally directed U-shaped portion 17 approximately on the plane of the downturned hooked portions, that opens in the lateral direction to- 4. ward which the hooks 16-16 are initially bent. The spacing of the hook groups at the joined ends of the V-shaped portions of the reinforcement anchoring means 14 is equal to the spacing of the vertical wires of the reinforcing curtain, for a purpose presently apparent.

As an alternative, the curtain anchoring means may be stamped from a flat sheet metal plate to provide a succession of integral V-shaped anchors 14g, each with an upturned hook it at its lower end, and adjacent parts 14g being joined by a flat portion p from the upper edge of wihch two spaced hooks kk, corresponding to the hooks 1616 of the device of Fig. 6, are bent laterally and downwardly for application to the lower wire of the curtain, as has been illustrated.

For the purpose of properly locating and aligning the curtain anchoring means 14 in the footing 12, I utilize a straight wooden strip 20. This may be a 2"x4" piece of lumber of the length of the footing, or wall section that is to be formed. Its opposite side surfaces are inclined as shown for easy removal of the piece rom the concrete after it has set, and it is formed, in its underface, with a deep cut channel 21 into which the hooks 16-16 of the anchor member may be forced and frictionally held, as has been shown in Fig. 7. The strip 29 is then fixed to the conventional footing crossties 22. and these are secured to the footing wall form members 1313. When the strip 20 has been properly aligned, it is fixed by tacking to the footing ties.

With the anchoring means 14 thus placed in position, the concrete for forming the footing is placed and allowed to set. Then ties 22 are pulled loose from the forms 13 and the strip 20 is lifted out, thus leaving the hook forming portions 16-16 of the anchor exposed, as in Fig. 7a in a channel in the footing. To anchor or attach the lower edge of the reinforcing curtain to the paired anchor hooks 1616 it is applied thereto as has been illustrated in Fig. 5 by engaging the lowermost horizontal wire of the curtain with the downturned pairs of hooks 16-16, with the vertical wires of the curtain passing between the paired hooks and seated in the loops 17. Then the curtain is lifted to a vertical position and drawn taut and secured by use of a plurality of grapple bars employed along the curtain for the application of prestressing tension thereto, constructed as follows. Each bar comprises a T-beam section 25 that is attached to the curtain along a part of its upper edge, as illustrated in Figs. 1 and 4. To provide for such attachment of the beam, a metal plate 26 is fixed, as shown in Fig. 10, to its lower edge to extend to the full length thereof. it has its lower edge portion turned laterally and upwardly and formed with recesses 27 at regular intervals of spacing, corresponding to the spacing of the vertical wires of the curtain, thus to provide a succession of upwardly facing grapple hooks 28 designed to seat the top horizontal wire of the reinforcing curtain therein. Each beam 25 is supported medially of its ends by a short cross arm 29, as shown in Fig. 10, that is bolted thereto. Each cross-arm 29 is supported at its opposite ends upon the upper ends of paired, extendable struts or jacks 3tl30, arranged at opposite sides of the curtain in the manner best shown in Fig. 4. At their lower ends the paired struts rest upon supporting brackets 32 which, in turn, are supported upon or by the footing 12. The spacing of the paired struts is greater at their lower ends than at their upper ends so that they will have a symmetrically converging relationship as positioned at opposite sides of the curtain.

The brackets 32 preferably are of the form shown in Figs. 4 and 11; each comprising a horizontal top plate 32a to the inner end of which an angle iron member 33 is fixed in position to seat the top longitudinal corner portion of the footing 10 therein. Each bracket 32 has a vertical inner edge 34 to the lower end of which a pad 35 is fixed to bear flatly against a side surface of the footing, as in Fig. 4. Paired brackets 3232 are arranged at opposite sides of the footing, in transverse alignment as shown in Fig. 2, and are then joined and supported by a tie strap 36 that is applied across the footing with its opposite end portions hooked through slots 37 in the horizontal flanges of the angle member 33. At their outer ends, the flat plates 32aare formed with short upwardly projecting lugs 38 over which the lower ends of the tubular struts 30 are applied to hold them in place. Likewise, the upper ends of the struts may be held agalnst slippage from the cross-aims 29 in a similar way by the application of their tubular end portions to lugs 39 extended downwardly from the cross-arms.

Each of the struts 30 which I now employ comprise a rather elongated tubular upper end section 30x within the lower portion of which the upper end portion of an extension tube 30y is telescopically contained. Below the lower end of section 30x, a sleeve 40 is slidable on the tube 30y, and is adapted to be supported at different positions therealong by a pin 41 projected through holes 41 formed diametrically through the tube. The sleeve 40 is exteriorly threaded, and adjustable therealong is a nut 42. Supported by the nut is another sleeve 43 that engages at its upper end against a washer 44 that is applied about the tube 30y and against the lower end of the tube 30x. Turning of the nut to move it upwardly on sleeve 40 causes a like lifting of the tube 30x.

It will be understood that with the paired struts 30-30 applied along opposite sides of the reinforcing curtain, in the manner as shown in Figs. 1 and 4, the reinforcing curtain can be drawn taut by extending the struts. Furthermore, the curtain can be placed under any desired amount of prestressing tension, and thereby rendered sufliciently rigid to serve its dual purpose as a support for the form walls.

It is also a function of the jacks or struts, as thus arranged, to adjust the length of the struts to efiect alignment of the curtain. Theoretically, if the brackets are properly set at the same level, and the struts, as applied thereto, are equally extended, the curtain will be held in a vertical plane. However, if for any reason the curtain should be found to vary from a desired vertical plane, this can be corrected by extending the strut at that side toward which the curtain leans and it will be shifted in the opposite direction accordingly. Thus, through the mediacy of the paired struts of adjustable length, and their yokes as applied end to end along the upper edge of the curtain, the curtain can be prestressed, and also brought to vertical position and into alignment from end to end. It follows also that the jacks may be used to effect extension or retraction of the struts as a means for disalignment or efiecting a predetermined leaning of the curtain and form if such should be desired.

With the curtain thus anchored, prestressed and aligned, it can be used for the support of the enclosing form walls in the manner now to be described.

The present enclosing forms are made of rectangular, longitudinally corrugated or ribbed sheet metal plates of a predetermined size. These sheets are arranged in horizontal courses, with adjacent vertical edges overlapped. The courses of plates are also overlapped, and may be placed in position as the concrete wall is built up. This provides that at no time will it he required that the concrete be dropped from any appreciable height in filling the form. The sheets or sections of corrugated sheet metal presently being used are twenty eight inches wide and sixty inches long. Adjacent sheets in the horizontal course are normally overlapped one corrugation or module, or as automatically provided by nesting one or more overlapped corrugations, but may be overlapped as many corrugations as required to fit the dimensional requirements of the structure. The structure should be designed in a module equal to one corrugation. Courses are normally overlapped about one foot, or to other distances as need be to best suit their place of use or height of wall. Ordinarily the corrugations will extend vertically,

and will correspond in spacing to the spacing of the ver tical wires of the reinforcing curtain.

In the present drawings, the opposite sidewalls of the enclosing forms are designated generally by reference numerals 5050. The sheet metal plates are designated individually by numeral 51.

Each of the plates or sections 51 of corrugated sheet metal is formed at the bases of its corrugations, with slots 52 aligned in rows across the plate as shown in Figs. 1, 8 and 12. These rows of slots are spaced apart at predetermined intervals to coincide with spacing of the horizontal members of the reinforcing curtain; the spacing interval to be determined by the particular use for which the form is to be used. When the sheet metal plates are arranged in courses with vertical edges overlapped and nested one within the other, as in Fig. 3, the slots in the overlapped edge portions can be brought into registration. Likewise, in the overlapping of the horizontal courses of assembled sheets, the slots of the overlapped portions can be readily brought into registration.

The means for anchoring the enclosing forms'to the reinforcing curtain, and for insuring an exact spacing of the form walls from each other and from the curtain, comprisesthe cross-ties t; each of which is made as shown in Fig. 9 from a single length of stiff wire of suitable gauge. Each cross-tie is a machine made article of exact and predetermined dimensions. The wire is bent mid-way of its ends to provide the two reversely turned

hook portions

53 and 54; hook 53 being in a horizontal plane and hook 54 being in a vertical plane. The opposite end portions of the wire are bent back upon themselves in such manner as to provide, at each end, an elongated loop or eye 55 which is designed for projection through any of the slots 52 of the corrugated metal plates. In the making of these cross-ties, stops 56 are incorporated in the opposite end portions thereof. These stops are accurately spaced from each other and from the

hook portions

53 and 54, and it is against the outer end surfaces of these stops that the form wall plates can be engaged to limit the extent to which the loops 55 can project through the plate slots and also to establish the exact spacing of the form walls 50-50 at opposite sides of the reinforcing curtain and from each other. I

As seen in Fig. 9, each stop is made from a sheet metal plate bent into conical form. Eachstop has a longitudinal diametrical portion that is disposed between the end of the corresponding loop forming portion and the main portion of the wire, and welded thereto. The stop has an outer end surface that is curved to fit against the curved surface of the base of the plate corrugation to which it is applied.

It is to be further explained that the cross-ties t are to be applied to the crossed wires of the curtain in such manner that they serve to draw the curtain wires together rather than pull them apart as will be understood by reference to Fig. 9. Furthermore, there is no slippage possible in this type of connection.

To build up the opposite sidewalls of the enclosing forms, corrugated metal sheets 51 are assembled to form the lower course at opposite sides of the curtain; the vertical edges of adjacent plates 51 being overlapped and the corrugations nested one within the other as shown in Fig. 3. As the plates are thus assembled, the end loops 55 of the cross-ties t, previously applied to the curtain in the manner shown in Fig. 9, are projected through selected slots 52 of the overlapped edges of the plates, and are anchored in the wall bracing wales 60 that are applied horizontally against the outer faces of the walls at desired levels.

The wales 60 are substantially T-shaped in cross-section, and preferably made of sheet metal strips bent to the cross-sectional form shown in Fig. 8. Each has the stem portion of the T formed by parallel, spaced side plates 60a and 60b, joined at their outer edges by a spacing web 60c, and having out-turned right angle wings 60f along their inner edges. Holes 62 are formed in vertical alignment through the spaced walls 60a and 6% adjacent their flanged edges, in locations to register with the end loops of the applied cross-ties, and wedge pins 65 are applied through these holes and the loops 55 thus to secure'the wales and draw them tightly into position against the form walls. With the wales properly located and thus secured, the walls of the form will be held secure, and straight, and in proper spaced relationship to each other and to the reinforcing curtain.

It is preferred that the sheet metal walls of the form be progressively built up as the concrete is placed. This eliminates the necessity of dropping the cement into the forms from any appreciable height, and gives easier access to the concrete as placed for tamping or packing about the reinforcing wires. Additional reinforcing rods may be placed as desired or required as the structure progresses.

After a form has been completed and filled, and the concrete has set, the jacks are retracted and the struts removed. Then the yokes 25 are detached from the upper edge of the reinforcing curtain. The wales 6d are then released by removal of the wedge pins, and the metal plates stripped from the wall.

The projecting end loops of the cross-ties can be readily snapped off by applying a fiat bar through them and twisting the loop. invariably the wire will break off at the small end of the cone shaped stops. In turning the loop, the diametrical portion of the stop will collapse, thus pulling the conical surface away from the concrete and permitting removal of the stop from the wall. The plates can be easily cleaned and made ready for reuse. The struts, wales and yokes do not ordinarily require cleaning prior to reuse.

Where corners are to be formed, special inside and outside plates, such as shown at 66 and 67 in Fig. 3, are provided. These plates are bent to right angular form and also are longitudinally corrugated and perforated with slots 52 to receive the cross-tie loops. Such corner members are also employed for the joining of partition walls to sidewalls as shown at 66a and 66b in the upper part of Pig. 3.

In Fig. 12, I have shown the manner of connecting a sidewall of a form with a soffit sheet. In this case, the soffit sheet 70 is of corrugated sheet metal with the corrugations transversely of the sheet. To join the parts, I employ an angular closure plate 74 with flanges 75a and 75b extending at right angles to each other and corrugated to fit within the corrugations of the sidewall plates and the soflit sheet. The parts are punched with slots 52 to receive anchoring ties as used for the sidewalls. While I have not herein illustrated such a construction, it is anticipated also that such soflit sheets may also be made to accommodate adjoining plates having corrugations that are parallel to the closure plate 74.

In Fig. 13, I have illustrated a form of plate locking key which is provided by cutting oif one end portion of a cross-tie as seen in Fig. 9. It has a loop portion designed for projection through aligned slots of overlapped plates, and carries the conical stop. When a key is applied through the loop, it locks the plates together.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is:

l. A form structure for use in the making of a poured concrete wall, in combination, a footing, a reticulated wall reinforcing curtain extended along said footing and anchored at its lower edge thereto, tensioning means attached to the curtain along its upper edge, supporting it rigidly and immovably in fixed position, form defining walls disposed at opposite sides of the curtain, and means fixing said walls to the curtain for support in spaced relationship for the reception of a wall forming material between them; said tensioning means being entirely independent of the form defining walls and detachable from the curtain after the poured concrete has set,

2. In combination, a footing, a reticulated wall reinforcing curtain extended along said footing and anchored at its lower edge thereto, tensioning means attached to said curtain along its upper edge and supporting it in fixed position and under tension, form defining walls disposedat opposite sides of the curtain, cross-ties anchored to the curtain and extended to opposite sides thereof and joining said walls in predetermined, spaced relationship to each other and to said curtain for the reception of a wall forming material between them; said tensioning meansbeing in the form of paired, extendable struts located at opposite sides of the footing, and extended above the top of the curtain, a cross-bar extended betweenthe struts at their upper ends and means on the cross bar releasably connected to the curtain.

3. in combination, a footing, a reinforcing curtain extended along the footing and anchored at its lower edge thereto, grapple bars of relatively short length, placed end to end along the upper edge of the curtain and detachably attached thereto, paired struts corresponding to each of said grapple bars arranged at opposite sides of the curtain, and supported from said footing and having connections at their upper ends with opposite ends of the corresponding grapple bar, said struts being extendable to subject the curtain to prestressing tension, and to hold it in a fixed position, cross ties of sufficient section to laterally support and restrain the walls under the fiuid pressure of the concrete upon them, applied to the curtain and extended to opposite sides thereof, and form defining walls supported on the footing at opposite sides of the curtain and held in predetermined spaced relationship to each other and to said curtain by said cross ties.

4. In combination, a footing formed with curtain anehoring means exposed along the top thereof, a reinforcing curtain of wire mesh formation extended along said footing and afiixed at its lower edge to said anchoring means, grapple bars extended end to end along the upper edge of the curtain and detachably fixed thereto, crossarms fixed to said bars and extended to opposite sides of the curtain, paired struts corresponding to the bars, arranged at opposite sides of the curtain, supports for said struts removably applied to and extended to opposite sides of the footing, said paired struts having supporting engagement at their upper ends with said corresponding cross-arms, and each being extendable for the applicatioh of prestressing tension to the curtain and relatively adjustable to effect lateral adjustment and to determine the curtain holding position of the grapple bar, form walls supported on the footing at opposite sides of the curtain, and cross-ties fixed to the curtain and detachably secured to said walls to give support thereto and to establish their spaced relationship to the curtain and to each other.

5. In combination, a footing, a reinforcing curtain extended along and anchored at its lower edge to said footing, laterally spaced form defining walls supported on the footing at opposite sides of the curtain, cross-ties joining said form defining walls, to each other and to the curtain, struts of adjustable length arranged in paired relationship at intervals along the curtain at the outsides of said form defining walls; said struts being supported at their lower ends from said footing and extended upwardly beyond the upper edge of the curtain and walls, cross-arms joining the upper ends of'paired struts, means on each of said cross arms effecting a tensioning connection with an upper edge portion of the curtain, and means associated with the paired struts for adjusting the tension as applied to the curtain thereby.

6. The combination recited in claim 5 wherein brackets corresponding-to the pairs of struts are disposed across said footing for support thereon, and extended beyond the opposite sides thereof, and wherein the paired struts are mounted on theopposite ends of said brackets, and wherein the paired struts are joined to said cross-bars in converging relationship and are independently adjustable in length to tension the curtain and to establish the fixed position of its upper edge as supported by said cross bars.

References Cited in the file of this patent UNITED STATES PATENTS Berry Nov. 30, 1915 Tutwiler June 26, 1917 Wolfe Sept. 6, 1921 Byrd Nov. 16, 1926 Gurley Oct. 8, 1929 Dresser Jan. 17, 1933 Smith Feb. 20, 1934 Kleitz May 8, 1934 10 Simpson Oct. 29, 1935 McDowell Jan. 30, 1936 Spies May 30, 1939 Symons Sept. 21, 1948 Boudousquie May 2, 1950 Hill June 13, 1950 Hawes July 25, 1950 Symons Feb. 5, 1952 Callan Apr. 29, 1952 Reitter July 19, 1955 FOREIGN PATENTS Switzerland Sept. 16, 1936