US20100301190A1

US20100301190A1 - Modular edge form system for cast in place suspended concrete slabs

Info

Publication number: US20100301190A1
Application number: US12/658,164
Authority: US
Inventors: Robert Showers Carney
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-02-03
Filing date: 2010-02-03
Publication date: 2010-12-02

Abstract

A modular edge form system for cast in place suspended concrete slabs, comprising wood or metal edge forms that close gaps between joists when a row of joists is above vertical supporting structures. The edge forms may depend on joists directly, or by means of wood edge form support structures; the joists in turn depend on joist hangers. Areas in front of the butt ends of joists are covered by means comprising the use of notch cover plates and/or bendable notch cover rectangles. The edge form system contains and supports cast-in-place horizontal concrete structures when they are poured and while they cure.

Description

I claim the benefit of the filing date of provisional application 61/206,697 filed on Feb. 3, 2009.

BACKGROUND OF THE INVENTION

Cast In Place suspended concrete slabs often have a haunch where the slab intersects vertical support structures, such as beams, girders, or walls. Formwork for constructing slabs often comprises a series of parallel joists that support top plywood sheathing. The joists are typically supported directly by the vertical support structures. Joist support means comprise re-useable adjustable hangers, and one-time use hangers or saddles, having elements that become permanently embedded in the structure. Because the top plywood sheathing is above the horizontal surfaces of vertical support structures, there is an edge gap from each joist to one or both adjacent joists. Edge forms are used to close this edge gap. One simple means often used by contractors is to nail or screw vertical plywood sections, or 1× lumber (such as 1×4's, 1×6's) to the bottom edge of the top plywood sheathing. This technique has limitations: the top plywood sheathing can deflect between the joists, and for higher haunches there is no means for supporting the bottom against the beam or girder.
Closing the edge gap should be seen as the minimum requirement of an edge form or edge form system. A more optimal modular edge forming system of the present invention comprises these structural and design elements: means for use with adjustable and reusable hangers suspended on a top surface of a vertical support structure; means for closing the edge gap for a range of haunch heights from zero to eight inches, or more; deflection support for the edges of top plywood sheathing; means for bracing an edge form against a vertical support structure to prevent or minimize leaking of concrete; means for forming suspended concrete slabs with curved perimeters; cooperative modular elements that can be combined in one or multiple way(s), as needed for a particular application; design and/or structural integration with other modular systems for forming suspended slabs; minimal or no use of nails and/or screws, resulting in faster and easier assembly and tear down, and no rusted nails remaining on the site for years.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises means for closing edge gaps between rows of joists used for concrete formwork, when the joists are above vertically supporting structures.
In a first embodiment, metal edge forms, having front faces, a top flange which depends on the ends of joists, one or more bottom reinforcing flange sections, and optionally a bottom flange reinforcing fold, and notches and/or side half-notches, sized with respect to the outer width of joist hangers, are held against the edge of a vertically supporting structure by sized notch cover plates having faces that are wider than the metal edge form notches and/or adjoining half-notches, and having tongues that are inserted between the butt end of a joist and the inner central wall of its supporting joist hanger. A wedge shim may be inserted behind the notch cover plate, to effect a tight fit of the joist within a pair of joist hangers. The joist hanger depends on the vertically supporting structure. The metal edge form flanges and joists are covered with dimensioned top sheathing, such that the edge of the sheathing is aligned with the front face of the metal edge forms. Surfaces of the supporting vertical structures, the metal edge forms, the notch cover plates, and the top sheathing contain and support cast-in-place horizontal concrete structures, typically including rebar and/or other structural elements, when they are poured, and while they cure.
In a second embodiment, wood edge forms, having front faces and upper support structures on each side, depend upon top wood edge form support structures, having wood edge form upper support housings on each side which engage with and support the wood edge form upper support structures, and having a top plate which depends on a joist. The joists in turn are supported by joist hangers; the joist hangers in turn depend on a vertical support structure. Embodiments of the top wood edge form support structures comprise a variant having gaps between a front face central tongue and outer front surfaces, allowing the central tongue to be inserted within a joist hanger when low haunches are required, and a variant with a continuous front face, used when the haunch height is high enough for the entire side face to be above the top of the joist hanger. When needed, at each joist butt end, sized notch cover plates having a central lower tongue may be inserted between the butt end of a joist and the inner central wall of its supporting joist hanger, supported from behind by the joist, and comprising faces that are sized to the outer width of the joist hangers, and recessed outer flanges sized to hold the wood edge forms against the edge of the vertically supporting structure. The two top wood edge form support structure embodiments can also be modified by adding angled support side plates that are perpendicular to the edge of the vertical support structure, to provide additional support in holding the wood edge forms against the edge of the vertically supporting structure. A wedge shim may be inserted behind the notch cover plate, to effect a tight fit of the joist within a pair of joist hangers. Additional bendable notch cover rectangles, or in some cases duct tape, may be used to close gaps. The wood edge forms and joists are covered with dimensioned top sheathing, such that the edge of the sheathing is aligned with the front face of the wood edge forms. Surfaces of the supporting vertical structures, the wood edge forms, the top wood edge form support structures, the notch cover plates, additional bendable notch cover rectangles, duct tape, and the top sheathing contain and support cast-in-place horizontal concrete structures, typically including rebar and/or other structural elements, when they are poured, and while they cure.
Wedge shims used to effect a tight fit of a joist supported within and between a pair of joist hangers may further comprise symmetrical horizontal slits and slit depth alignment lines, dimensioned to allow upper portions of the shim to be snapped off if necessary.
It will be understood that embodiments of joist hangers of the present invention may be adjustable. It will be further understood that while embodiments of the present invention presented are rendered with respect to vertical edge gaps, the present invention can, with suitable modifications, also be practiced for edge gaps that are set at an angle to the vertical plane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a joist hanger of the present invention, having a vertical hanger support structure, and depending on a vertical support structure.

FIG. 2 is a perspective view of a metal edge form of the present invention, with additional isometric perspectives.

FIG. 3 is an exploded and perspective view of notch cover plates of the present invention, together with shim, joist, and joist hanger elements, with additional isometric perspectives.

FIG. 4 is a perspective view of wood edge form elements of the present invention, with additional isometric perspectives.

FIG. 5 is a perspective view of top wood edge form support elements and wood edge form elements of the present invention, with additional isometric perspectives.

FIG. 6 is a perspective view of top wood edge form support elements and wood edge form elements of the present invention, with additional isometric perspectives.

FIG. 6A is a perspective view of top wood edge form support elements and wood edge form elements of the present invention, with additional isometric perspectives.

FIG. 6B is a perspective view of top wood edge form support elements and wood edge form elements of the present invention.

FIG. 7 is an exploded and perspective view of notch cover plates of the present invention, together with shim, joist, and joist hanger elements, with additional isometric perspectives.

FIG. 8A is an exploded view of metal edge form, notch cover plates, shim, joist, and joist hanger elements, of the present invention, situated with respect to a vertical support structure edge line.

FIG. 8B is a partially exploded and partially assembled view of metal edge form, notch cover plate, shim, joist, and joist hanger elements, of the present invention, situated with respect to a vertical support structure edge line.

FIG. 8C is an assembled view of notch cover plate, shim, joist, and joist hanger elements, of the present invention, situated with respect to a vertical support structure edge line, and prior to final positioning of a metal edge form element.

FIG. 8D is a fully assembled view of metal edge form, notch cover plate, shim, joist, and joist hanger elements, of the present invention, surmounted by top plywood sheathing, and situated with respect to a vertical support structure edge line.

FIG. 9A is a partially exploded and partially assembled view of wood edge form, notch cover plate, shim, joist, joist hanger, and notch cover rectangle elements, of the present invention, situated with respect to a vertical support structure edge line.

FIG. 9B is an assembled view of notch cover plate, shim, joist, joist hanger, and top plywood sheathing elements, of the present invention, situated with respect to a vertical support structure edge line, prior to final positioning of notch cover rectangle elements.

FIG. 9C is an assembled view of notch cover plate, shim, joist, joist hanger, notch cover rectangle, and top plywood sheathing elements, of the present invention, situated with respect to a vertical support structure edge line.

FIG. 9D is an assembled view of a low haunch configuration of shim, joist, joist hanger, and top plywood sheathing elements, of the present invention, situated with respect to a vertical support structure edge line, and prior to final position of a notch cover rectangle element with tongue.

FIG. 10 is a perspective view of a wedge shim of the present invention having symmetrical horizontal slits and slit depth alignment lines.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a modular haunch forming system for forming cast in place suspended concrete slabs. Elements comprising the system will first be presented and illustrated individually, followed by explanations and illustrations of the elements in use, individually, in combination with other elements, and in combination with other modular systems for forming suspended slabs. It should be noted that while dimensions will be indicated for certain embodiments based on U.S. construction industry standards, the present invention can be practiced with embodiments having other dimensions.
FIG. 1 illustrates an embodiment of one modular element of the present invention, comprising an adjustable and reusable joist hanger, 101, supported vertically by a top lip, 102, depending on top surface of a vertical support structure, 151. The embodiment of the vertical support structure of FIG. 1 is a steel I-beam, 152, having a horizontal top flange, 153, and a recessed inner web, 154. A vertical hanger support structure, 104, in this embodiment a section of 2×4 lumber, is attached to central face, 103, of the joist hanger, 101. The vertical hanger support structure, 104, provides vertical support for the joist hanger, 101. Some vertical support structures, such as walls or preformed concrete girders, have a vertical side of sufficient length such that a vertical hanger support structure, 104, is not required. The joist hanger, 101, supports a joist, 130, resting on a top plate within the hanger body (not shown). The height of the joist, 130, can be adjusted by means of the screw part, 120.
FIG. 2 illustrates an embodiment of a metal edge form, 201, of the present invention, comprising a front face, 202, a central hanger notch, 203, a right hanger half notch, 204, a left hanger half notch, 205, a central upper notch cover, 206, a right upper half notch cover, 207, a left upper half notch cover, 208, a top flange, 209, a top flange central nailing hole, 210, bottom reinforcing flange sections, 211, and bottom flange reinforcing folds, 212.
FIG. 3 illustrates three embodiments of sized notch cover plates of the present invention, for use with the metal edge form, an embodiment of which is shown in FIG. 2. Referring to FIG. 3, all three notch cover plate embodiments comprise a central metal edge form notch cover bottom tongue, 254. The metal edge form 2″ notch cover plate, 251, comprises a metal edge form 2″ notch cover upper plate, 256, that is 4″ wide and 2″ high. The metal edge form 4″ notch cover plate, 252, comprises a metal edge form 4″ notch cover upper plate, 257, that is 4″ wide and 4″ high. The metal edge form 6″ notch cover plate, 253, comprises a metal edge form 6″ notch cover upper plate, 258, that is 4″ wide and 6″ high.
The assembly of the sized notch cover plates is similar for the three embodiments, 251, 252, and 253, illustrated in FIG. 3. Referring to the top left exploded view, the bottom edge of the metal edge form notch cover shim, 255, is aligned with the bottom edge of the upper plate, 256, and is between the upper plate, 256, and the notch cover bottom tongue, 254. The upper edge of the notch cover bottom tongue is aligned with the upper edge of the notch cover shim, 255. Both the notch cover bottom tongue, 254, and the notch cover shim, 255, are centered with respect to the center point of the bottom edge of the upper plate, 256. The three elements can be spot welded at the center. For additional reinforcing, the notch cover shim, 255, can also be spot welded on each side to the upper plate, 256. All elements comprising the sized notch cover plates for the metal edge forms can be made of mild steel. Embodiments of the sized notch cover plates may have upper plates in a sized range of heights.
The thickness of the upper plates, 256, 257, and 258, must be such as to provide sufficient stiffness when the notch cover plates support the metal edge forms from behind against the weight and impact of poured concrete. The thickness and dimensions of the notch cover bottom tongue, 254, must be both thick enough to securely anchor the notch cover plates, 251, 252, and 253, between the inside of the joist hanger body, 105, of an adjustable and reusable joist hanger, 101, and the butt end of a joist, 130, and must be thin enough to ensure they can be inserted even when joists, 130, are already snug against the inside of the hanger body, 105. The thickness and dimensions of the notch cover shim, 255, must be such as to provide sufficient added stiffness to the bottom of the of upper plates, 256, 257, and 258, when the notch cover plates, 251, 252, and 253, support metal edge forms from behind against the weight and impact of poured concrete, and to provide space for an upper section, 172, of a wedge shim, 171, that may optionally be placed between the notch cover plates, 251, 252, and 253, and the butt end of a joist, 130, such that an upper section, 172, of a wedge shim, 171, that may be above the top edge of the bottom tongue, 254 will not engage with the back of the upper plates, 256, 257, and 258, pushing the notch cover plate away from the butt end of a joist, 130.
FIG. 4 illustrates three embodiments of rectangular wood edge forms of the present invention. Embodiments of wood edge forms can be made of three quarter inch thick plywood, or 1× lumber, (examples: 1×4, 1×8). A first embodiment, 301, comprises a sized rectangular section of three quarter inch plywood, having a front face, 304, four sides perpendicular to the front face, 304, two vertical support top slits, 305, and two upper support structures, 307. Multiple embodiments of the upper support structure, 307, are illustrated in FIG. 4. The vertical support top slits, 305, are approximately 1.5 inches deep. The first embodiment of the upper support structure, 308, further comprise a side edge that is perpendicular to both the front face, 304, and the upper side, 306, and is planar with the vertical sides. The second embodiment of the upper support structure, 309, further comprises an upper support structure angled side, 311, rendered such that the wider bottom side, 314, of the second upper support structure, 309, is recessed from the perpendicular side, 315, no more than half the depth of the vertical support top slit, 305, when this slit depth is measured from the perpendicular side, 315. The third embodiment of the upper support structure, 310, further comprises a right rear beveled side, 312, having an angle of approximately 20 degrees to 30 degrees, and running the length of the right perpendicular side, 316, and a right upper support structure front chamfer, 313, with a depth of approximately one quarter inch, and running no more than half the depth of the vertical support top slit, 305.
FIG. 5 illustrates a first embodiment of a top wood edge form support, 351, rendered from a flat formed plate, 358, of 16 gauge mild steel, and further comprising a top plate, 352, that is supported by the upper edge of a joist, a nailing hole; 353, in the top plate, 352, a central tongue, 356, two hanger side slots, 357, a left wood edge form upper support housing, 354, having a front face, 359, and a right wood edge form upper support housing, 355, having a front face, 360; the front faces 359 and 360 are in the same plane, and together define a rectangular area that is the front face of the top wood edge form support, 351, The central tongue, 356, may be recessed back from the plane of the front faces 359 and 360, such that the wood edge form, now referring to FIG. 9D, is held more closely against a vertically supporting structure edge line, 155.
FIG. 5 further illustrates upper support structures, 307, of a first wood edge form, 301, engaged with a left wood edge form upper support housing, 354, and a right wood edge form upper support housing, 355, of a top wood edge form support, 351, of the present invention. A side view and a top view of a wood edge form support, 351, of the present invention are also illustrated in FIG. 5.
FIG. 6 illustrates a second embodiment of a top wood edge form support, 371, rendered from a flat formed plate, 378, of 16 gauge mild steel, and further comprising a top plate, 372, that is supported by the upper edge of a joist, a nailing hole, 373, in the top plate, 372, a left wood edge form upper support housing, 374, a right wood edge form upper support housing, 375, and a front face, 376. FIG. 6 further illustrates upper support structures, 307, of a first wood edge form, 301, engaged with a left wood edge form upper support housing, 374, and a right wood edge form upper support housing, 375, of a top wood edge form support, 371, of the present invention. A side view and a top view of a wood edge form support, 371, of the present invention are also illustrated in FIG. 6.
FIG. 6A illustrates a third embodiment of a top wood edge form support, 381, identical to the top wood edge form support, 371, of FIG. 6, except, referring again to FIG. 6A, for the addition of two lower angled edge form support side plates, 382, attached by means such as welding to the top wood edge form support, 371. The lower angled edge form support side plates, 382, have lower front edges, 383, that are aligned with the plane of the rear inner wall, 384, of the left and right wood edge form upper support housings, 374 and 375, respectively. These lower front edges, 383, hold wood edge forms such as the wood edge form, 301, parallel to the top wood edge form support front face, 376, when pressure is applied to the front of the edge forms, 301, as during concreting.
FIG. 6B illustrates a top wood edge form support, 391, comprising the top wood edge form support, 351, of FIG. 5, and, referring now to FIG. 6A, the angled edge form support side plates, 382. Referring now to FIG. 6B, the left and right wood edge form upper support housings, 354 and 355 of the top wood edge form support, 391, function in an identical way, referring now to FIG. 6A, as the left and right wood edge form upper support housings, 374 and 375, referring again to FIG. 6B, with respect to the lower front edges, 383, of the angled edge form support side plates, 382. The top wood edge form supports, 381 and 391, hold the wood edge form against the edge of the vertically supporting structure, 155. For some low haunch applications, the top wood edge form supports 351 of FIG. 5, and/or the top wood edge form supports 371 of FIG. 6, may be substituted for the top wood edge form supports 381 and/or 391 of FIG. 6B. This can be structurally adequate for low haunches; however, as the haunch height increases, the weight and impact force of poured concrete can push the bottom of the wood edge form, 301, away from the edge of the vertically supporting structure.
FIG. 7 illustrates three embodiments of sized notch cover plates of the present invention, for use with the wood edge forms of FIG. 4. Referring to FIG. 7, all three notch cover plate embodiments comprise a central wood edge form notch cover bottom tongue, 454. The wood edge form 2″ notch cover plate, 451, comprises a metal edge form 2″ notch cover upper plate, 456, having a front face, 459, that is 4″ wide and 2″ high, adjoining right and left side wood edge form support structures, 460, further comprising a recessed side, 461, approximately perpendicular to the front face, 459, and dimensioned to the width of the wood edge forms, and a wood edge form support flange, 462, approximately perpendicular to the recessed side, 461, and sufficiently wide to support wood edge forms such as those of FIG. 4 from behind. The wood edge form 4″ notch cover plate, 452, comprises a metal edge form 4″ notch cover upper plate, 457, having a front face, 459, that is 4″ wide and 4″ high, adjoining right and left side wood edge form support structures, 460, further comprising a recessed side, 461, approximately perpendicular to the front face, 459, and dimensioned to the width of the wood edge forms, and a wood edge form support flange, 462, approximately perpendicular to the recessed side, 461, and sufficiently wide to support wood edge forms such as those of FIG. 4 from behind. The wood edge form 6″ notch cover plate, 453, comprises a metal edge form 6″ notch cover upper plate, 458, having a front face, 459, that is 4″ wide and 6″ high, adjoining right and left side wood edge form support structures, 460, further comprising a recessed side, 461, approximately perpendicular to the front face, 459, and dimensioned to the width of the wood edge forms, and a wood edge form support flange, 462, approximately perpendicular to the recessed side, 461, and sufficiently wide to support wood edge forms such as those of FIG. 4 from behind. The upper plates, 456, 457, and 458, for the illustrated embodiments, may be formed from rectangles of mild steel, 463, by bending along the illustrated dashed lines, using means such as a punch press, or a press brake.
The assembly of the sized notch cover plates is similar for the three embodiments, 451, 452, and 453, illustrated in FIG. 7. Referring to the top left exploded view, the bottom edge of the metal edge form notch cover shim, 455, is aligned with the bottom edge of the upper plate, 456, and is between the upper plate, 456, and the notch cover bottom tongue, 454. The upper edge of the notch cover bottom tongue, 454, is aligned with the upper edge of the notch cover shim, 455. Both the notch cover bottom tongue, 454, and the notch cover shim, 455, are centered with respect to the center point of the bottom edge of the upper plate, 456. The three elements can be spot welded at the center. For additional reinforcing, the notch cover shim, 455, can also be spot welded on each side to the upper plate, 456. All elements comprising the sized notch cover plates for the metal edge forms can be made of mild steel. Embodiments of the sized notch cover plates may have upper plates in a range of heights.
The thickness of upper plates, 456, 457, and 458, must be such as to provide sufficient stiffness when the notch cover plates support the metal edge forms from behind against the weight and impact of poured concrete. The thickness and dimensions of the notch cover bottom tongue, 454, must be both thick enough to securely anchor the notch cover plates, 451, 452, and 453, between the inside of the hanger body, 101, and the butt end of a joist, 130, and must be thin enough to ensure they can be inserted even when joists, 130, are already snug against the inside of the hanger body, 101. The thickness and dimensions of the notch cover shim, 455, must be such as to provide sufficient added stiffness to the bottom of the upper plates, 456, 457, and 458, when the notch cover plates, 451, 452, and 453, support metal edge forms from behind against the weight and impact of poured concrete, and to provide space for an upper section, 172, of a wedge shim, 171, that may optionally be placed between the notch cover plates, 451, 452, and 453, and the butt end of a joist, 130, such that an upper section, 172, of a wedge shim, 171, that may be above the top edge of the bottom tongue, 454 will not engage with the back of the upper plates, 456, 457, and 458, pushing the notch cover plate away from the butt end of a joist, 130.
FIG. 8A illustrates an exploded view of embodiments of elements of the present invention comprising three adjustable and reusable joist hangers, 101, situated with respect to a dashed vertical support structure edge line, 155, three joists, 130, three wedge shims, 171, three metal edge form 4″ notch cover plates, 252, and a metal edge form, 201.
FIG. 8B illustrates a partial assembly of the exploded elements of FIG. 8A. Referring to FIG. 8B, on the left, a metal edge form 4″ notch cover plate, 252, is inserted into an adjustable and reusable joist hanger, 101, and rests against the butt end of a joist, 130. In the middle, a lower section, 173, of a wedge shim, 171, has been inserted between the inside of the body of an adjustable and reusable joist hanger, 101, and the butt end of the joist, 130. As previously noted, the use of wedge shims is optional, but may be desirable to ensure a tight fit for formwork elements.
FIG. 8C shows all three adjustable and reusable joist hanger, 101, having metal edge form 4″ notch cover plates inserted, as described with respect to FIG. 8B.
FIG. 8D illustrates a completed assembly, comprising a metal edge form, 201, supported vertically by the joists, 130, and supported against the weight and impact of the concrete by the metal edge form notch cover plates, 252, which in turn are supported by the butt ends of the joists, 130. Top plywood sheathing, 161, is placed on top of the joists, 130, and the metal edge form top flanges, 209, such that the dimensioned edge of the top plywood sheathing, 161, aligns with the front face, 202, of the metal edge form, 201. The joists, 130, and the top flange, 209, of the metal edge forms, support the top plywood sheathing, 161, against deflection caused by the weight and impact of poured concrete, reinforcing elements, and live loads during concreting. The height of the central upper notch cover, 206, and the opposite left and right upper half notch covers, 208 and 207 respectively, as measured down from the adjoining top flange, 209, is such that, referring now to FIG. 3, the height of a series of upper notch cover plates, 256, 257, and 258, is in increments less than or equal, now referring again to FIG. 8D, to the height of the central upper notch cover, 206, and the opposite left and right upper half notch covers, 208 and 207 respectively. Therefore, whatever the height of the notch gap, measured with respect to the lower edge of the notch covers or notch half covers, 206, 207 and 208, and the upper surface of the top lip, 102, of the adjustable joist hanger, 101, that is covered by a sized notch cover plate, such as the 4″ notch cover plate 252, one embodiment of a sized notch cover plate will be available that will fully cover the notch gap, but will not be as high as the distance from the metal edge form top flange, 209, and the upper surface of the top lip, 102.
The FIG. 9 series, illustrating deployment of embodiments of wood edge forms of the present invention, is similar to the FIG. 8 series, illustrating deployment of embodiments of metal edge forms of the present invention. FIG. 9A illustrates a partial assembly and a partial exploded view of embodiments of elements of the present invention comprising adjustable and reusable joist hangers, 101, positioned with respect to a vertical support structure edge line, 155, joists, 130, a first wood edge form, 301, a second wood edge form, 302, a third wood edge form, 303, a top wood edge form support, 351, top wood edge form supports, 371, wood edge form 2″ notch cover plates, 451, a wood edge form 4″ notch cover plate, 452, a middle notch cover rectangle, 481, a middle notch cover rectangle bent, 482, and a middle notch cover rectangle with tongue, 483, further comprising a tongue, 485.
FIG. 9B illustrates the assembled elements of FIG. 9A, further comprising top plywood sheathing, 161, but without the use, referring now to FIG. 9A, of the middle notch cover rectangle, 481, or the middle notch cover rectangle with tongue, 483. Referring now to FIG. 9B, the deployment of the wood edge form 4″ notch cover plate, 452, illustrates that in combination with the top wood edge form support, 371, the space between wood edge forms, 301 and 303, adjacent to the left adjustable and reusable joist hanger, 101, is completely covered. The height of the top wood edge form supports, 351 and 371, is such that, referring now to FIG. 7, the height of a series of upper notch cover plates, 456, 457, and 458, is in increments less than or equal, now referring again to FIG. 9B, to the height of the top wood edge form supports, 351 and 371. Therefore, whatever the height of the notch gap, measured with respect to the lower edge of the top wood edge form supports, 351 and 371, and the upper surface of the top lip, 102, of the adjustable joist hanger, 101, that is covered by a sized notch cover plate, such as the 4″ notch cover plate 452, one embodiment of a sized notch cover plate will be available that will fully cover the notch gap, but will not be as high as the distance from the lower surfaces of the top plates, 352 of FIG. 5, and 372 of FIG. 6, now referring to FIG. 9B, of the top wood edge form supports, 351 and 371, and the upper surface of the top lip, 102.
Continuing to refer to FIG. 9B, the center adjustable and reusable joist hanger, 101, illustrates the deployment of a top wood edge form support, 371, and a wood edge 2″ notch cover plate, 451. While these two elements provide top and bottom support for the wood edge forms, 301 and 303, and hold the bottom of the edge forms tight against the vertical support structure edge line, 155, there is a gap between the top wood edge form support, 371, and the wood edge 2″ notch cover plate, 451. This gap can be covered with duct tape in some cases. Alternatively, as illustrated in FIG. 9C, this gap can be covered with a middle notch cover rectangle, 482, placed at the bottom between the wood edge 2″ notch cover plate, 451, and the butt end of the joist, and bent at the top of the joist. Referring now to FIG. 9B, the right adjustable and reusable joist hanger, 101, illustrates the deployment of a top wood edge form support, 351, and a wood edge 2″ notch cover plate, 451. While these two elements provide top and bottom support for the wood edge forms, 301 and 303, and hold the bottom of the edge forms tight against the vertical support structure edge line, 155, there is a gap between the top wood edge form support, 351, and the wood edge 2″ notch cover plate, 451. In addition, referring now to FIG. 5, the hanger side slots, 357, must be covered, referring now to FIG. 9B, to close up the formwork structure. These gaps and openings can be covered with duct tape in some cases. Alternatively, referring now to FIG. 9C, these gaps and openings can be covered with a middle notch cover rectangle, 482, placed at the bottom between the wood edge 2″ notch cover plate, 451, and the butt end of the joist, and bent at the top of the joist, covering the central area, of the top wood edge form support, 351.
FIG. 9D illustrates the use of a top wood edge form support, 351, where a low haunch is required. The central tongue, 356, of the top wood edge form support, 351, is partially inserted between the adjustable and reusable hanger, 101, and the butt edge of the joist. The top wood edge form support, 351, can be used for haunches such that the central tongue, 356 is fully inserted. The openings left by the hanger side slots, 357, can be covered by duct tape, or by the use of a middle notch cover rectangle with tongue, 483, also illustrated as bent, 484, comprising a lower tongue section, 485, that is inserted at the bottom between the body of the adjustable and reusable joist hanger, 101, and the central tongue, 356, of the top wood edge form support, 351, and that is bent at the top of the joist. The middle notch cover rectangle with tongue, 483, may also be used with the top wood edge form support, 371, of FIG. 6, with higher haunches, and also, referring now to FIG. 6B, with the top wood edge form supports having angled edge form support side plates, 381 and 391.
FIG. 10 illustrates an embodiment of an element of the present invention, comprising a wedge shim 171, having a series of horizontal slits, 174, symmetrically on each side of the central vertical axis of the wedge shim, 171. The depth of these horizontal slits, 174, can be dimensioned with respect to wedge shim slit depth alignment lines, 175, such that the depth of the horizontal slits, 174, decreases as the width of the wedge shim decreases, and the depth of the horizontal slits, 174, increases as the width of the wedge shim increases. These shims can be used to advantage with respect to embodiments of other elements of the present invention, because a top section of the wedge shim can be broken off by pulling the top portion of the wedge shim to either side. Standard shims can typically be broken off by pulling forward, but cannot be broken off by pulling to either side. Referring now to FIG. 3, the advantage of limiting the height of an upper section, 172, of a wedge shim, 171, is that a short upper section, 172, will not tend to push notch cover plates away from the butt ends of joists, while a longer upper section, 172, may do so.
Referring to FIG. 1, while this specification has focused on embodiments of the present invention deployed with adjustable and reusable joist hangers, 101, having a top lip structure, 102, that is wider than the joist, 130, it should be understood that alternative embodiments of the present invention may be deployed with other means for suspending joists, and variants of embodiments of the present invention may comprise notch widths sized to the width of joists, or other supporting members, rather than to the width of the top lip structure, 102, of the embodiment of the adjustable and reusable joist hanger, 101.
It will be understood that embodiments of joist hangers of the present invention may be adjustable. It will be further understood that while this specification has focused on embodiments of the present invention rendered with respect to vertical edge gaps, alternative embodiments of the present invention may be employed when edge gaps are set at an angle to the vertical plane. It will be further understood that embodiments of the wood edge forms may have curved surfaces.
The modular edge form system of the present invention offers these advantages with respect to the prior art:

- It is suitable for use with adjustable and reusable hangers suspended on a top surface of a vertical support structure.
- It provides means for closing the edge gap for a range of haunch heights from zero to eight inches, or more.
- It provides deflection support for the edges of top sheathing.
- It provides means for bracing an edge form against a vertical support structure to prevent or minimize leaking of concrete.
- It provides means for forming suspended concrete slabs with curved perimeters.
- It comprises cooperative modular elements that can be combined in one or multiple way(s), as needed for a particular application.
- It is design for structural integration with other modular systems for forming suspended slabs.
- It can be practiced with minimal or no use of nails and/or screws, resulting in faster and easier assembly and tear down, and no rusted nails remaining on the site for years.

Claims

1. A modular edge form system for cast in place suspended concrete slabs, comprising:

a. metal edge forms, having a front face, a top flange which depends on a joist, one or more notches and/or side half notches sized to the outer width of a joist hanger, one or more upper notch covers and/or half notch covers, and one or more bottom reinforcing flange sections between the notches, and

b. a series of sized notch cover plates having faces wider than the metal edge form notches and/or adjoining half-notches, and having a range of heights such that the height increments are equal to or less than the height of the said upper notch covers and/or half notch covers of the said metal edge forms, and having tongues that are inserted between the butt end of a joist and the inner central wall of a joist hanger depending on a vertically supporting structure, such that the sized notch cover plates hold the said metal edge forms against the edge of the said vertically supporting structure, and

c. top sheathing placed on top of the joists and on the metal edge form top flanges, and dimensioned such that the edge of the sheathing aligns with the front face of the metal edge forms.

2. The modular edge form system of claim 1 further comprising front faces of the said metal edge form that are vertical.

3. The modular edge form system of claim 1 further comprising bottom reinforcing flanges of the said metal edge form that further comprise a reinforcing fold.

4. The modular edge form system of claim 1 further comprising a nailing hole in the said metal edge form top flange.

5. The modular edge form system of claim 1 further comprising a said joist hanger that is adjustable.

6. The modular edge form system of claim 1 further comprising a wedge shim having a series of horizontal slits symmetrically on each side of a central vertical axis, the depth of these horizontal slits being dimensioned with respect to the varying thickness of the wedge.

7. A modular edge form system for cast in place suspended concrete slabs, comprising:

a. wood edge forms, comprising a front face and upper support structures on each side, and

b. top wood edge form support structures, comprising a front face, and further comprising wood edge form upper support housings on each side which engage with and support the wood edge form upper support structures, and further comprising a top plate which depends on a joist, and

c. the joist depending on a joist hanger, the said joist hanger in turn depending on a vertically supporting structure, and

d. top sheathing placed on top of the joists and on the wood edge forms, and dimensioned such that the edge of the sheathing aligns with the front face of the wood edge forms.

8. The modular edge form system of claim 7, further comprising one or a series of sized notch cover plates, the said notch cover plates further comprising a central lower tongue, and further comprising faces that are sized to the outer width of the said joist hangers, recessed outer flanges sized to hold the said wood edge forms against the edge of the said vertically supporting structure, and, for a series of the said sized notch cover plates, front face height increments that are less than the height of the front face of the said top wood edge form support structures.

9. The modular edge form system of claim 7, further comprising a said top wood edge form support top plate having a nailing hole.

10. The modular edge form system of claim 7, further comprising a said top wood edge form support top plate having a recessed front face central tongue sized to be inserted within a said joist hanger, and further comprising, between the said central tongue and the said upper support housing front faces, gaps sized to the width of the outer sides of the said joist hanger.

11. The modular edge form system of claim 7, further comprising a said top wood edge form support top plate having a continuous rectangular front face comprising the said upper support housings.

12. The modular edge form system of claim 7, further comprising a said top wood edge form support having lower angled support side plates perpendicular to edge of the vertical support structure, and having lower front edges that are aligned with the plane of a rear inner wall of the said upper support housings.

13. The modular edge form system of claim 7 further comprising front faces of the said wood edge form that are vertical.

14. The modular edge form system of claim 7 further comprising a said joist hanger that is adjustable.

15. The modular edge form system of claim 7 further comprising a wedge shim having a series of horizontal slits symmetrically on each side of a central vertical axis, the depth of these horizontal slits being dimensioned with respect to the varying thickness of the wedge.

16. The modular edge form system of claim 7 further comprising a bendable middle notch cover rectangle, having a lower tongue section.