US2307678A

US2307678A - Collapsible wall form

Info

Publication number: US2307678A
Application number: US242506A
Authority: US
Inventors: Hayes Hal
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-11-26
Filing date: 1938-11-26
Publication date: 1943-01-05
Anticipated expiration: 1960-01-05

Description

/NI/E/VTOR v HAL HA YES ATTORNEYS 5 Sheets-Sheet 1 HA HAYES COLLAPSIBLE WALL FORM Flled Nov 26, 1958 Jan. 5, 1943.

Jan-5, 1943. H1 HAYES 2,307,678

COLLAPSIBLE WALL FORM Filed Nov. 2e, 1.958 5 sheets-Sheet 2 Jan. 5,

Filed Nov. 2'6, 193s H. HAYES coLLAPsIBLENwALL FORM i 5 Sheets-Sheet 3 Hll wvl/avro@ y HAL HAYE Arron/Veys Jan. 5, 1943. HAYES coLLAPsIBLE WALL FORM Filed` Nov. 26, 1938 /NVE/VTOP vHAL. HAY/'55 A ATTORNEY Jan. '5, 1943. H: HAYES CLLAPSIBLE WAL;I BORM 5 sheets-Sheet 5 Filed Nov. 2e, 1938 /fvV/VTOR HAL HAYES Patented Jan. 5, 1943 UNITED STATESPATENT OFFICE COLLAPSIBLE WALL FORM Hal Hayes, Los Angeles, Calif. Application November 26, 1938, Serial No. 242,506

8 Claims.

This invention relates to building construction and particularly pertains to collapsible wall forms.

Heretofore, buildings have been made of concrete in which temporary moulds have been built to receive poured concrete and which segmental pre-formed moulds have been builtto be erected and dismantled or moved in units. Such structures have been shown in my patent entitled Concrete forms issued by the United States Patent Oice September 29, 1936, and bearing the Number 2,055,977. These structures necessitate the separate erection of a plurality of wall sections which are assembled as erected to form a wall of predetermined area and must thereafter be separately removed. In connection with these sections it is necessary t provide means to properly align the sections with relation to each other so that the corners of the walls will be square and so that the wall surfaces will be plumb. It has been found desirable to design a concrete form in which all of the wall sections are permanently assembled with relation to each other so that the form for a complete room or building section may be manufacturedand thereafter set in place, and it is the principal object of the present invention to provide a building form stmoture having elements which may be moved as a unit to delineate and form the walls of a room or series of rooms and which will cooperate with other form elements to provide form spaces into which cementitious material may be poured, the invention having the further object in view of providing cooperating members to form wall openings and in constructing the forms so that they may be withdrawn from contact with the cast wall surfaces and thereafter withdrawn from position within the cast structure by simple and direct acting means.

The present invention contemplates the provision of a form structure which is collapsible in arrangement and which collapsible structure cooperates with other form elements to provide a hollow Wall for a room of any given dimension and to cast wall openings therein as required.

The invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a view in transverse vertical section through a wall formed with the present apparatus and indicates the positions of the inside and outside forms with which the present invention is concerned.

Fig. 2 is a fragmentary view in vertical transverse section showing another form of footing construction than that disclosed iny Fig. 1.

Fig. 3 is a view in transverse section as seen on the line 3 3 of Fig. 2 showing a oor or ceiling construction.

Fig. 4 is a fragmentary view similar to that disclosed in Fig. 3 showing a form of footing and anchor for the form elements.

Fig. 5 is a view in plan showing the construction of the inside room form.

Fig. 6 is a view in vertical section and elevation through the inside form as seen on the line 6 6 of Fig. 5.

' Fig. 7 is a fragmentary View in elevation as viewed in the direction of the arrow 'I in Fig. 5

and discloses the adjusting and aligning means of the form.

Fig. 8 is a fragmentary view in vertical section and elevation showing a wall footing construction.

Fig. 9 is a fragmentary view in vertical section showing a temporary positioning means for wall forms.

Fig. 10 is a view similar to Fig. 9- showing another form of wall forming positioning means.

Fig. 11 is a view in plan showing an inside wall form in which wall slabs are hinged together.

Fig. 12 is a view in elevation showing this particular form as collapsed. Y

Fig. 13 is a fragmentary view of a wall showing means provided for casting a wall opening in a wall section.

Fig. 14 is a view in transverse section as seen on the line |4-I4 of Fig. 13, showing the construction of the frame and wall opening.

Fig. 15 is a fragmentary Aview in perspective showing the means of locking wall form elements together along their contiguous edges.

Fig. 16 is a fragmentary view in plan showing the manner in which the corners of wall form elements are secured together.

Fig. 17 is a view drawn at a reduced scale showing the construction of one of the outer wall form elements.

Fig. 18 is a fragmentary ViewV yin perspective showing an expanding unit for increasing the length of a form and the manner in which it is locked.

Fig. 19 is an enlarged fragmentary View in perspective showing the form locking and centering means along contiguous edges.

Fig. 20 is a view in perspective showing the upper portion of the form structure as assembled as indicated in Fig. 1 but more particularly disclosingt the manner in which a lling hopper is placed in position.

Referring more particularly to the drawings,

I9 indicates a concrete footing. This footing delineates the outline of the rooms of a dwelling and provides a foundation therefor. In the form of the footing, as shown in Fig. l, it is constructed with a relatively wide portion seated within a trench in the ground and an upper relatively narrow portion projecting above the ground. This upper portion has a horizontal face II and side faces I2. The footing, as will be understood, is preferably made of cementitious material. Disposed at opposite sides of the upwardly projecting portion of the footing and lying against the faces l2 are supporting rails I3 and I4. These rails may be secured in position in any desired manner. The rail I3 may support a floor slab I5, the upper face of which lies in the same horizontal plane as the face II of the footing.

Extending across the face I I and over the upper face of the floor slab, as shown in Fig. l, are spacing bars IG which may be held in position in any suitable manner such as for example by driving a nail I'I through an opening therein and then driving the nail into the rail I4. Thev spacing bars I9 are formed with angle elements I3 at their outer sides with relation to which outer wall forms I9 are held against spreading action and with their plane surfaces in vertical alignment with the face I2 of the footing.

Detachably mounted on the upper face of the inner ends of the spacing bar I6 are channel members 29. These members are secured in position upon the bars by cap screws 2l. The outermost leg of these channel members stands vertically and abuts against the back face of inner wall forms 22. Locking pins 23 extend horizontally from the outer legs of the channels 20 and interlock with the form 22 to be held against movement. The opposite legs of the channel elements20 are engaged by a spacing bar 24.

Detachably secured to the outer extending ends of the bars I6 are diagonal bracing members 25 which are fitted with jaws 26 and a set screw 21 for clamping them in position where required. The upper ends of these members are secured by elements 28 to the frame structure I9. The frame structure I9 is formed with a continuous smooth surfaced plate 29 whichrepresents the area to be moulded. As here shown, this plate is of a height equal to the height of the wall to be cast. It is bounded around its edges by reinforcing angles 30, and as shown in Fig. 17 of the drawings may be vertically and horizontally reinforced by structural members 3| and 32. Suitable vertically Vextending trusses 33 are provided and where required horizontally extending trusses 34 are used. This insures that although the plate 29 is of relatively thin gauge that it will be reinforced to withstand considerable pressure uniformly exerted by the mass of concrete being cast into the wall. This general type of form was shown in United States Letters Patent No. 2,055,977 issued to me on September 29, 1936.

Resting upon the spacing bars I6 are removable core structures 35 which are preferably of the type shown in my co-pending application entitled Collapsible core, Serial No. 169,098, filed by me on October 15, 1397. This type of core is characterized bythe fact that its side walls 3B are articulately connected to each other and may be held in their expanded positions by suitable expanding means 3.1 and 38 which bear against reinforcing ribs 39. The upper end of the core is held in its expanded position and in its spaced relation to the form elements I9 and 22 by spacing bars 49, which carry lugs 4I and 42 extending downwardly into the mouth of the core and between the walls 36. The lug 42 is mounted upon a swinging lever 42. The member 40 carries a cover plate 43 which closes the space between the plate 29 and the wall plate 36.

After the forms have been set a hopper structure is placed over the open top of the forms as shown in Fig. 2i). This structureincludes cross members 49 and-a leverr 4,0' having a catch 44 which fits beneath the upper angle element 39 of the frame E9 and holds the bar down and in position. An angle hook 44 is carried at the opposite endV of the bar 49 and when disposed beneath the flange of a frame element 54 will cooperate with the lever 49 in holding the bar 49 in place. Carried by one or more of the spacing bars 49 is a hopper 45 by which concrete may be filled into the spaces 46 and 4l occurring around thecores 35 and between the form elements i9 and 22. Thus', it is possible to quickly fill these spaces while holding the various form elements in proper assembled and spaced relation to each other.

A feature of particular importance in the present case is the construction of the inside forms, generally indicated at 22 and shown in particular in Figs. 5 and 6of the drawings. These forms dene the inside wallof a room. Heretofore, at least four forms have been required to delineate theinside wall-surface. Withthe present invention one form unit is provided, around which the outside forms I9 are arranged and which inside form unit may be set in position as aunit and removed therefrom in the same manner as removing a collapsible core 35 ina wall section. The inside form 22 comprises

side wall sections

49, 59, 5I and 52, as here shown, for producing a room space of' rectangular shape. It is to be understood that the dimensions of the various walls might be changed or that other room configurations might be made without departing from the spirit of theA invention.

As shown in Fig. 5, the various wallsections 49 to 52, inclusive, are each constructed from continuous sheet plates 53 which'are bent at the corners and which are reinforced b-y horizontal angle'members 54 and 4vertical trusses 55.v The sheet plates 53 bent around thecorners abut against each other along vertical lines as at 53. These edges'are reinforced by the angle members 32. The angles areheld together as shown in Fig. 19 and in a manner to be hereinafter explained. v

Attention is directed to the fact that the horizontal angle members 54 are of a length shorter than that represented by the wall form upon which they are applied so that'spaces 56 may occur at the corners of the form 22, thereby allowing a limited amount` of articulate action between the various form sections at the corners so that the entire form structure 22 may be contracted sufficiently after a form has been made to draw it out of contact with the moulded surface and to permit it to be lifted from the enclosure without frictional engagement between the surfaces of the member 53 and the wall which has been cast.

The form structure 22v is braced between opposing walls by collapsible bracing elements 51 and is braced diagonally from points adjacent the corners of the form by adjustable' braces 58. The Gellapsible braces 51 are hinged at 59 to vertical truss members 55 of the form and are hinged also at 60 to a vertical draw-bar 6|. This draw-bar extends to a point above the top of the form structure 22 and is provided with an eye 62 in which a hoisting hook maybe placed.

The cross brace members 51 when pulled inwardly, as'their upper pivoted ends are pulled upwardly by the member 6I, will tend to deflect the plate 53 between its corners and will pull the plate away from the surface of the moulded mass of cementitious material so that thereafter the form 'may be elevated from the confined area produced by the moulded wall. This flexure extends entirely to the corners which may ex also to accommodate the action. In order to hold the wall structure against flexure while the concrete is being poured the brace members 51 may be moved to a horizontally aligned position, as shown in Fig. 6 of the drawings. This action will be supplemented by the action of the diagonal members 58 which comprise a horizontal compression element 63 resting upon the end of a compression element 64. The element 63, as particularly shown in Fig. '7 of the drawings, is formed with a flange 65 through which a bolt 66 is threaded. This bolt bears against a stop member 61 rigidly secured to th'e compression member 64 so that pressure may be exerted to hold the

compression members

63 and 64 in a rigid distended position between their points of contact with the wall form sections. A lock nut`68 is provided on each of the bolts. Rigid horizontal members 51 are carried by the post 62 and their outer ends serve as stops against which members 55 may move when the form is being collapsed; n

In the form of the invention shown in Figs. 11 and 12 the inside form structure 22 is shown as being collapsible so that it may be more readily transported from place to place. In this particular device the

side wall sections

49, 50, and 52 are each made with a permanent corner 69 adjacent to which is a vertical hinge 1Il.v The vertical hinge thus does not occur in the corner but adjacent thereto, thus insuring that the corner which is moulded will not be irregular or broken, and at the same time insuring that the frame may be collapsed and readily withdrawn from position within the moulded structure.

It may be found desirable to vary the construction of the footing I0 and to temporarily anchor the form elements by different arrangements. Such variations are shown in Figs. 2, 4, 8, 9 and 10. In Fig. 2 it will be seen that the footing I9 is formed with a shoulder 1|, upon which a fioor joist 12 may rest. This beam is indicated in Fig. 3 as being cast of cementitious material and tied to the floor slab I5 by suitable reinforcing and tie means 13. The wooden members I3 and I4 are Varied accordingly and are here shown as secured together by tie bolts 14 which extend through the mass of concrete and carry

plates

15 and 16 to hold the form sections I9 and 22 in position.

In the form of the invention shown in Fig. 4 the construction of Fig. 2 is varied slightly and the floor slab is supported upon a transverse beam I3 Separate fastening and seat members `11 and 18 are provided which receive the lower edges of the frame structures I9 and 22 and are bolted together by the bolts 14.

In the form of the invention shown in Fig. 8 side beams I3 and |4 carry

angle members

19 and 89 which are secured in place by bolts 14. Theangle members thus present a horizontal face upon which the 4form sections I9 and 22 may rest. Angle bars 8| and 82 are carried on the angle'members and limit outward movement of the form elements during the moulding operation.

Figs. 9 and 10 show structures in which the form elements are set up on a oor. l In Fig. 9 the floor slab I 5 is shown as being formed with'

channels

83 and 84 in which the form elements I9 and 22 may be positioned. In Fig. 10 lock screws` 85 havingT-heads are positioned in the oor to limit outward movement ofthe form structures I 9 and 22 and to hold the lower edges of the form structures against the floor during the moulding operation. Y

As previously explained, it is desirable to provide form means by which door and window openings may be cast by the use of th'e moulds here disclosed. This is accomplished by providing a metal window frame 88 whichrnay be set in a position and filled with concrete permanently so that when the forms I9 and 22 are removed the window frame will be a permanent part of the wall. The window frame structure Vis held in position by a frame 81 which fits within the opening of the window frame. Bolting Vplates 98'are provided and may receive bolts 89 .extending through openings in the plates of the form structures VI9 and 221to properly support and position the frame. The frame l81 is indicated as being of angle sectioned material and carries a plurality of saddle members 90. These members, as shown in Fig. 14 of the drawings,extend over the face of the'inner perimeter of the window frame 86 to position the same. The saddles are suitably secured to the frame structure 81 by cap screws 9|. Plates 92 are secured to the frame structure for the purpose of withdrawing the supporting frame 81 after the wall frames I9 and 22 have been removed. It will thus be seen that by this varrangement it is not necessary to cut wall openings after the concrete has been set, for these open'- ings are cast utilizing the permanent window frame as the mould therefor.

In some instances it may be necessary to conneet aplurality of frame sections I9 along their A vertical edges. A suitable arrangement is shown in Fig. 15 of the drawings where the contiguous vertical anges 30 carry overlapping structural` elements 93 andy 94 which when assembled, as shown in Fig. 15, will receive a `pin 95 to hold them together. The-upper edges of the frame structuresmay be held together by a channell plate 96 which has overlapping flanges 9 1 extending downwardly along opposite faces of the forms.

' `In order to secure the forms together at the corners an angle member 98 is provided, as shown in Fig. 16 of the drawings. This member is formed with openings to receive pins 99 which fit into the corner between the angles 38 ofthe frame structures.

In operation of the present invention a footing or base structure may be made as required. It has been found in practice that it is only necessary to provide arrelatively shallow foundation trench `which delineates the oor plan of the building, after which the footings I0 are cast to form the foundation. These footings may be as desired, such for example as shown ini Figs. 1, 2, 4 and 8. When a floor has already been laid the form elements may be erected on the floor and in the caseV of concrete flooring means for positioning the forms may be utilized as shown in the Figs. 9A and 10. In any event the inside form V221s set in position with its transverse brace members 51 disposed horizontally as shown in Fig. 6 of the drawings and with the diagonal bracing 58 set by the adjusting screws 66 to hold the structure rigid. This internal frame may be locked and held by any of the means shown in Figs. l, 2, 4 and 8 and will thus retain its position when the force of poured concrete is exerted against it.

In the form of the invention shown in Fig. 1

a lower cross brace 24 is provided to extend from one side wall of the room to the other and to hold the positioning means 20 in place. It may also be found desirable to brace the form at intervals throughout its height and space the core structures 35 with means such as the transverse brace rod lf2-0 shown in Fig. 1 of the drawings. Here it will be :seen that this brace rod extends into a sleeve IUI and may project through an opening in the plate 53 of the form 22 to be imbedded temporarily in the concrete, as indicated by dotted lines. After the concrete has been poured it may be withdrawn to the position indicated in solid lines and the pin |62 inserted through another opening in the member |012 to hold it in place and prevent leakage of concrete. The outer form elements may then be erected with reference to the positioning member I3, as shown in Fig. 1 of the drawings. If the outer forms require more than one form section the contiguous vertical edges may be fastened together, as shown in Fig. 15, and at the corners the edges of the form sections may be fastened together as shown in Fig. 16. The cores 35 may then be lowered into position, after which the bars 40 are disposed over the top ofthe cores so that their spacing lugs .43 will extend between the

form walls

29 and 53 and the core walls 36. The bars 4B may then be secured in position, as shown in Fig. 1 of the drawings. y

As previously explained, a hopper 45 is carried by certain of the bars 4l! so that concrete may be easily poured into the hopper and directed into the spaces 4S and 41 occurring at opposite sides of the core. In the event that wall openings are required, the frames 86 for such openings may be secured in position by the holding frames 81. The concrete may then be poured.

After the concrete is set the forms I9 and 22 may be removed. The inner form 22 is removed by releasing the compression of the adjusting bolt 66 on the diagonal member 58 and removing braces suchas indicated at 24 and IDB. The vertical bar 6I may then be grasped and pulled upwardly. This will pull the outer ends of the transverse brace members 51 inwardly and will fiex the plate 53 between the corners, after which further upward movement will cause the entire form structure to be lifted from position. The outer frame elements I9 may then be taken down. It is to be understood that the wall opening frames 81 will have been detached from the form structure I9 or 22 to which it had been secured so that it will remain in place until after the side forms have been taken down. 'Ihe saddle members 90 will then be detached from the frame structure 87 so that the frame structure and the saddle members can be removed from the position shown in Fig. 14.

In the form of the invention shown in Fig. it has been described that the plates 53 are bent around the corners of the form so that they will flex and so that the edges of the plates meet as is shown at 53. These meeting edges are reinforced by the vertical angle elements 30, which elements include means for readily aligning the plates with relation to each otherfand means for locking the plates. Such means are shown in Figs. 18 and 19 of the drawings, where it will be seen that the angle member 30 of one plate 53 carries a series of aligningpins H0 which are preferably square or rectangular in section and project into corresponding openings IH in the parallel flange of a contiguous angle member, Also carried by the flange of an angle member 30 is a plurality of lock pins H2 which project through openings H3 in the adjacent ilange of a contiguous angle plate. The projecting portion of the pins. I I3 are formed with vertically extending slots H4 which receive wedge members H5. These wedge members may be driven down into position and will tightly draw the adjacent flanges of the contiguous angles 3U against each other.

t is to be understood that. due to variation in the lineal dimensions of rooms it may be desirable to increase the length of a side of a room over the length created by the plates 53. This is accomplished by providing intermediate members H6 which are in the shape of wall form slabs and which may t between the contiguous edges 53 of the wall forms. These slabs may be of any desired width and are provided with the interlocking and holding means shown in Figs. 18 and 19. It will thus be seen that due to this particular arrangement it is possible to quickly assemble a form unit which will take care of a wall, defining the perimeter of a room of any desired dimensions.

It will vthus be seen that by the construction here disclosed a complete building including any desired number of rooms and any desired room arrangement may be quickly built in a monolithic structure, whichinsures that a building of suitable strength -may be constructed at a relatively small cost both.- as to material and labor.

While I have shown the preferred form of my invention and method of using the same, it will be understood that various changes may be made in combination, construction and arrangement of parts by those skilled in the art, without departing from the spirit of my invention as claimed. Y

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

1. In combination, an outer form element resting upon a foundation footing, means holding said outer form elementagainst relative movement with relation to said footing, an inner collapsible form unit resting upon said footing and including all wall sections corresponding to the wall of an enclosure to be formed, means holding said inner form element against lateral movement relative to the footing and the first form element, means at the upper edges of said form elements for spacing and holding said elements with their opposing faces in spaced parallel relation to each other, an intermediate core element resting upon the footing and positioned between said form members, and means extending through the wall of a form member for temporarily holding the intermediate core in a fixed position while cementitious material is being poured around it, after which said intermediate core may be collapsed and retracted from the mass of material forming the wall.

2. In combination with an outer wall form dening the vertical outer face of a wall of an enclosure such as a room. an inner wall form spaced from the outer wall form with vertical faces parallel to thefaces of the outer wall form, said inner wall form being characterized as comprising a continuous form. unit including inner wall form sections for each of the wall surfaces to be formed, said sections having limited ilexibility between wall corners, means associated with said wall form sections whereby force may be exerted against said sections to cause the same to flex, means connected with said force exerting means for lifting the entire wall form structure bodily from the enclosure, and means for limiting the flexing movement of the wall form sections.

3. In combination with an outer wall form defining the vertical outer face of a wall of an enclosure such as a room, an inner wall form spaced from the outer Wall form with vertical faces parallel to the faces of the outer wall form, said inner wall form being characterized as comprising a continuous form unit including inner wall form sections for each of the Wall surfaces to be formed, said sections having limited ilexibility between wall corners, means associated with said wall form sections whereby force may be exerted against said sections to cause the same to flex, means connected with said force exerting means for lifting the entire wall form structure bodily from the enclosure, and separate means for positively and temporarily holding said Wall form sections against exure.

4. In combination with an cuter wall form defining the vertical outer face of a wall of an enclosure such as a room, an inner wall form spaced from the cuter wall form with Vertical faces parallel to the faces of the outer wall form, said inner wall form being characterized as comprising a continuous form unit including inner wall form sections for each of the wall surfaces to be formed, said sections having limited flexibility between wall corners, means associated with said wall form sections whereby force may be exerted against said sections to cause the .same to flex, means connected with said force exerting means for lifting the entire wall form structure bodily from the enclosure, and separate means for positively and adjustably holding said wall form sections against flexure.

5. In combination with an outer wall form structure adapted to define the outer vertical surfaces of a wall forming an enclosure such as a room or the like, an inner form structure comprising panels defining the inner wall faces of the enclosure, said panels including sections articulately associated at their corners and capable of limited flexibility throughout the horizontal length of the wall sections, separate means connected with said panels intermediate their ends and extending diagonally of the inner form structure whereby the panels will be positively locked against iiexure and whereby movement of said means to unlocked positions will flex the panels and contract the form, and lifting means associated therewith to lift the form thus contracted.

6. In combination with an outer wall form structure adapted to define the outer vertical surfaces of a wall forming an enclosure such as a room or the like, an inner form structure comprising panels defining the inner wall faces of the enclosure, said panels including sections articulately associated at their corners and capable of limited flexibility throughout the horizontal length of the wall sections, separate means connected with said panels intermediate their ends and extending diagonally of the inner form structure whereby the panels will be positively locked against flexure and whereby movement of said means to unlocked 4positions will flex the panels and contract the form, lifting means associated therewith to lift the form thus contracted, and diagonal brace members adjustably positioned within the form structure at points adjacent to the corners thereof whereby the form will be held against collapse when cementitious material is being poured around it.

7. In combination with an outer wall form structure adapted to dene the outer vertical surfaces of a wall forming an enclosure such as a room or the like, an inner form structure comprising panels defining the inner wall faces of the enclosure, said panels including sections articulately associated at their corners and capable of limited flexibility throughout the horizontal length of the wall sections, separate means connected with said panels intermediate their ends and extending diagonally of the inner form structure whereby the panels will be positively locked against flex-ure and whereby movement of said means to unlocked positions will flex the panels and contract the form, -form splicing slabs adapted to be interposed between contiguous vertical edges of the panel members, and means for locking said slabs in position.

8. In combination an outer Wall form structure adapted to define the outer vertical surface of a wall forming and enclosure such as a room or the like, an inner form structure comprising panels :defining the inner wall faces of the enclosure, said form structures being in spaced relation to one another between which cementitious material may .be poured, collapsible means carried by said form elements and bridging the space therebetween to block out a' desired area between the forms whereby when the wall is cast a wall opening will be formed completely therethrough, said inner form structure comprising panels defining the inner Wall Afaces of the enclosure, said panels including sections articulately associated at their corners and capable of limited, flexibility throughout the horizontal length of the wall sections,

means connected with said panels intermediate' their ends whereby the panels will be positively locked against flex-ure and whereby movement of said means to unlocked positions will flex the panels and contract the form, and lifting means associated with the panels to contract and lift the form.

HAL HAYES.