US 3582035 A
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United States Patent  inventors David R. Wells Westminster, 0110.; James W. Franklin, Albuquerque, N. Mex.  Appl. No. 644,529  Filed June 8, 1967  Patented June 1, 1971  Assignee Structural Voids, lnc.
 CONCRETE PAN FORMING SYSTEM 13 Claims, 14 Drawing Figs.
 US. Cl 249/18, 249/176, 249/194  Int. Cl E04g 11/36  Field of Search 249/32, 31, 28,129,130,26,124,122,ll9,176,177, 219, 194; 25/1 18 (M)  References Cited UNITED STATES PATENTS 2,940,152 6/1960 Riehl 249/194X FOREIGN PATENTS 596,334 1/1948 Great Britain 249/194 522,427 4/1955 Italy 249/194 Primary Examiner-J. Spencer Overholser Attorney-C. B. Messenger ABSTRACT: A pan-forming system and accessories therefore utilizing loose sheet components held together in operative relationship by said accessories, in which lip members on said accessories or elements of the accessories are engaged between adjacent sheet materials as spacers holding said sheet components slightly spaced apart to facilitate stripping of said PATENTEU JUN I |97l SHEEI 1 OF 4 nu nl/l Ill/A o 3 v m 3 Z we 9. a a a m 9 3\ 3. .u u
DAVID WELLS ATTORNEY PATENTEDJuu 1197! 3,582,035
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DAVID R. WELLS BY JAMES w. FRANKLIN PATENTED'JUN new 3582.035
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DAVID R. WRELLKS N JAMES w. F AN Ll EH3. 9 BY W 1 TTORNEY SHEET 4 [IF 4 PATENTEU JUN 1 I97! Z AWN v I INVENTOR.
7 DAVID R. WELLS B JAMES w. FRANKLIN AT TOR N EY 1 CONCRETE PAN FORMING SYSTEM BACKGROUND OF THE INVENTION In order to increase the span between vertical supports in concrete construction, other inventors and engineers have previously recognized the advantage of providing pan-forming systems for localized reduction in the thickness of the concrete section or floor being poured. Previous pan systems have been provided which leave joist like elements extending in oneor more directions across the total span of the floor system being poured. A one way system would provide a plurality of parallel joist structures, while a two way" system would provide intersecting joists to give the underneath side of the poured floor a grid or a waffle like appearance. Over a long period of years different pan-forming systems have been derived to meet such user requirements. Metal, wood and cardboard form elements have been-used to obtain desirable floor systems. At the present time greater spans between vertical supports have become desirable for purposes of economy of construction as well as for convenience of building use. These factors give new impetus to the use of pan floor systems and make it worthwhile to provide a pan form system of greater utility in conventional and long span construction.
The utility of any pan-forming system is determined by several factors: The cost of pan elements; the ease and cost of placement and support; whether or not the pan elements are reusable; the adaptability of the pan elements to provide floor systems having pan voids of varying depth, width or length; the ease with which the pans may be removed and whether the pan-forming system components may be removed before the main support or shoring elements are-removed; the detail, finish or decorative pattern provided by the pan form elements; whether or not the pan form elements are useable for the support, placement and fastening of reinforcing elements or utility components that are to be embedded in the floor system; and the ability of the pan-forming system to withstand loads imposed by poured concrete and personnel or equipment use during construction operations.
No previously used pan-forming system has provided the best possible answer to all requirements, and, accordingly, different systems have been extensively used in connection with different types of construction. Metal and fiberglass pan forms are expensive, and the single size and shape characteristic tends to limit design possibilities in use. Previous wood systems have entailed an excessive labor cost for placement and removal, and it is difficult to efficiently reuse wood elementsthat have been nailed in conventional manner. Wood forms have previously been difficult to strip without incurring some damage to form elements or the poured concrete.
Cardboard form systems have recently attained, more widespread usage, since they are relatively easy to install, the core elements are directly reuseable, and design variations are possible without excessive cost. Limitations include an inadequate depth of pan for long span and high load installations, inadequate anchors for utility placements, and the necessity for form and shore removal before the pans are freed for reuse.
SUMMARY OF THE INVENTION The presentinvention provides brackets and accessories that may be used together with panels-of sheet material to construct pans on either open or closed form work supports and for either one way or two way systems. In general, the accessory items serve to hold plywood sheet components in operative position for forming the desired structural voids in a poured floor system. The panels andbrackets that are used may be easily stripped from set concrete, since each accessory item provides a lip or element extending between adjacent form panels to hold such panels slightly apart in their assem bled relationship. This panel spacing action makes it easier to strip the panels and form components after the concrete has been poured and set. In use of the system the gaps left by said LII spaced-apart panels can, in generaL-be closed through use of tape or other gap spanning elements that are easily removable when the pan system is removed.
The brackets used in connection with open form work support systems provide adjustment features so that they may be used on pans of different depth. When used in connection with an open center forming operation, components of the present pan system can be completely stripped as soon as the concrete has set without disturbing the open center supports and shore elements. Accordingly, a limited number of pan-forming components can be used to form floors at different elevations or at different locations to complete all forming operations in less time and at less cost. The floor can still be fully supported during a prescribed curing period by the left in place shores without tying up the pan-forming components.
Since the plywood panel elements used can be of different thickness and strength, it is possible to provide the deeper pans or voids in a structural floor that are beneficially used when high floor loadings or long spans are desired. The installed pans are sturdy and durable to withstand all concrete or operational loadings, and structural reinforcing and utility installations can be directly anchored to the plywood panel components to securely hold such elements in place during pouring or erection operations. Many beneficial features are derived from this combination of a plywood panel system and metal brackets for holding said panels in desired relationships, in which the required structural strength is cooperatively provided by the strength of the panels themselves and per manence of the metal bracket elements.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view illustrating one wayjoist con' struction on open center soffet shoring,
FIG. 2 is a perspective view illustrating one wayjoist construction on solid decking,
FIG. 3 is a perspective view illustrating two wayjoist construction on open center soffet shoring,
FIG. 4 is a perspective view illustrating two wayjoist construction on solid decking,
FIG. 5 is a perspective view in partial section showing a one way rib pan with a top panel in alternate removed position,
FIG. 6 is a perspective view in partial section showing a two way rib pan with a top panel in alternate removed position,
FIG. 7 is a perspective view of a line or side panel clip,
FIG. 8 is a perspective view in partial section showing a one way pan or open center forming,
FIG. 9 is a perspective view in partial section showing a two way pan on open center forming,
FIG. 10 is a perspective view of a spreader element support clip,
FIG. 11 is a perspective view in partial broken section illustrating a corner bracket for a solid deck-forming system,
FIG. 12 is a perspective view in partial broken section illustrating a side bracket for a solid deck-forming system,
FIG. 13 is a perspective view with partial broken section illustrating a corner bracket for use in an open center-forming system, and
FIG. 14 is a perspective view illustrating a side bracket for use in an open center-forming system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 through 4 illustrate use of the invention in connec tion with the construction of one way" and two way floor pan systems in which pans are supported either by an open center soffet type of forming or on a closed deck.
FIG. I shows a poured floor deck 21 in which longitudinal joists 22 have been provided to extend between elements providing vertical support for the floor deck. The longitudinal joists 22 have reinforcing elements 23 disposed in the lower portions of the joists to increase the tension resistance of the floor system. All of the floor slab elements are supported by form work when the floor is being prepared and poured.
An open center soffet type of forming is used in FIG. I, in which soffet boards 24 provide the main longitudinal support for the floor system. Bracing and form shores will be disposed directly beneath the soffets 24 to hold the form work in elevated position above the building foundation or previously poured lower floors. The floor slab 21 has a reduced cross section in the areas between adjacent joists 22 to reduce the overall weight and cost of the floor. The spaced joists 22, which can be of deep section, provide increased tension resistance for the support of the floorand for support of the working and dead loads that will be applied as the building is used. Where long spans are desirable between vertical supports, the joists 22 will be of deep section, and, accordingly, the voids between adjacentjoists will likewise be of considerable depth.
In order to form, mold and establish such voids, the applicants provide a rib pan-forming system in which panels of plywood are used as the pan-forming elements. The plywood may be of thickness as necessary to support the weight and hydrostatic pressures of the wet concrete that is to be placed as well as personnel or equipment loadings incident to placement and pouring operations. For a way or a rib pan system the main panel components include the side panels 26 and a top panel 27 spanning the distance between the vertical or upwardly disposed side panels 26. In order to provide an efflcient system which may be readily assembled and in which the panel components are reuseable, any nailing of the panels 26 and 27 together is avoided. Support brackets and clips made and used in keeping with this invention are used to hold these panel components in their illustrated assembled relationship.
The construction features of the brackets and clips used in the forming of an open center system, such as that of FIG. I, are shown in FIGS. 7, 8 and I4. Where open center forming is used in connection with a two way" or waffle pan design, the comer brackets 28 as shown in FIGS. 8, 9 and I3 are used in place of or together with the side brackets 29 as shown in FIGS. 1,8and l4.
Identical pan voids can be provided where a solid deck or closed type of forming system is to be used. The longitudinal pans ofa one way rib pan-forming system are shown in FIG. 2. A two way" forming system on solid deck supports provides an interrupted waffle pattern when the form pans of FIG. 4 are used. For these types of forming operations, corner brackets 38 and side brackets 39 are provided to be erected above the platform provided by the solid deck 31. In the erection of said closed form system the clips 32, as shown in FIG. 7, may be placed on the deck 31 to receive and hold the side panels 26. The same clips 32 may also be used to support the side panels 26 of the open center-forming system as shown in FIGS. 1, 3, etc. The detailed construction features of the comer and side brackets and the clips which are used to support the plywood panels of the various forming systems are shown in greater detail in some of the additional drawings herewith presented.
Before reference to such drawings, however, it would be well to note that when the panels are erected a minor gap or open space 33 will be left between adjacent panel elements. Before a floor system is to be poured the gap 33 between the side panels 26 and top panels 27 can be closed to prevent loss of cement or water through said gap. Various types of adhesive tape 34 may be applied along the edges of the positioned pans to close off such gap where a better finish is required on the set concrete. Since the pressure of the poured concrete is exerted against the tape in a direction tending to increase the adhesive bond and since the gap is quite narrow, various types of economical paper or other types may be used to provide good results.
In the forming of a two way" system as shown in FIGS. 3 and 4, end panels 36 will be used to close off individual voids and to form diaphragm elements or cross joists 37 extending between or intersecting the longitudinal joists 22. Separate reinforcing bars 23 may be placed in all of these intersecting channels to increase the support strength of the poured concrete slab. Since gaps 33 will also purposely occur at the joint between the end panels 36 and the top panel 27, tape 34 can likewise be applied to close off such gaps.
As stated, these gaps between the panels making up the pan form system are purposely provided to maintain clearance between all of the form panels. The form system may be removed from a poured and cured slab much easier when the panels are not joined rigidly to each other, as by nailing, and may be even more easily removed when the panels are spacedapart in such manner that they won't be brought into tight contact one with the other under the pressure and weight exerted by the placed concrete. After the concrete has been poured and set and the soffets or the solid deck form supports are removed, the side panels 26 can then be easily pried loose from the concrete for removal. Movement of the side and end panels will also loosen the top panel so that all elements are easily freed from the concrete. The noted ease of removal is in large measure due to the gaps provided between all of the otherwise contacting panel elements.
The bracket and clip components which serve to support the form panels and to maintain the desired gap feature are shown in best detail by the perspective drawings FIGS. 1]- l4. FIGS. 11 and 12 are directed to a solid deck-forming system, while FIGS. 13 and 14 illustrate components for an open center-forming system.
In FIG. 11 a corner bracket 38 is shown. The corner bracket essentially provides an L-shaped or angle-type upright standard 41 having a foot piece 42 at its lower end adapted for engagement with the deck components 31. The foot piece 42 preferably provided with a plurality of holes 43 so that conventional or scaffold-type nails 44 may be engaged therein. The comer bracket 38 is provided with a top support 46 that extends between the elements of the L-shaped standard 41 and is preferably joined to both flanges thereof. The top support 46 is positioned away from the upper end 47 of the bracket 38 a distance less than the thickness of the form material that will be used for the top panels 27. This construction provides flange extensions 48 that continue upwardly past the edges of any top panel positioned on the support 46. Accordingly, the flange extensions 48 create and tend to maintain the desired gaps 33 between the side end and top panels.
One further gap preserving element is provided on the comer brackets 38 by the tabs 49 that are struck out of one side flange. Preferably these tabs are formed by stamping the tab from the tab opening 51 before the angle is bent along the bend line 52. A similar result can be obtained, however, by providing a tab 49 that is struck from or attached to a preformed angle piece. When the tab extends outwardly away from the bracket 38 and in the same plane as one of the component flanges of the bracket, the tab may be positioned between end and side panels to provide a vertical gap 33.
Line clips 32 of the type shown in FIG. 7 may be used to position the side or end panels 26 and 36 on the deck 31. Where such clips are used, a gap 33 will again be left between the panels and deck element 31. Where desired, tabs of thickness corresponding to the thickness of the clips 32 may be positioned on the bracket 38 as continuations of the foot piece 42. These tabs would also extend under the panel members to preserve the gap. The clip 32 shown in FIG. 7 has a back element 53 and upstanding sides 54. Extensions of the back may be provided with openings 56 so that the clips can be easily nailed to the deck pieces 31 or soffet boards 24.
FIG. 12 presents details in the construction of side brackets 39 for closed center form work. It will be seen from this illustration that the side bracket 39 has an upright strap segment 57 and a bent foot 58 providing nail openings 49 for the reception of scaffold or regular nails 44. An angle support element 61 is welded or otherwise fastened to the strap 57 in position away from the top end of the strap to provide a strap extension segment 62 extending above the platform provided by angle support 61. The strap extension 62 again provides a spacer which holds the top panel 27 and side panel 26 in the desired spaced-apart relation.
A corner bracket 28 for open center-type form work is shown in FIG. 13. The bracket is in most constructional details similar to the corner bracket 38 illustrated in FIG. 11. Accordingly, the bracket provides an L-shaped upright standard 41, a top support 46, flange extensions 48 and tabs 49 which are struck from the material of one of the flange sides of the angle standard. For open center form work the corner bracket 28 is not provided with a foot piece. The bracket can be longer and a plurality of sets of paired holes 63 are punched in the bracket 28 so that the bracket maybe raised or lowered with respect to the soffet forms 24 to be held at the desired elevation by application of nails through one set of paired openings 63 directly into the soffet boards 24, as shown in FIG. 13, or through the side panels 26 and into the soffet 24 when the form of construction shown in FIG. 8 is used. With the nails applied, the bracket 28 will be held at desired elevation so that the top panels 27 and end panels 26 and 36 may be applied to complete a pan or void forming element. The plurality of paired openings 63 make it possible to use a single set of open center support brackets for the forming of voids that may be of varied depth, width or length.
In the construction of either corner brackets 28 or 38 a structural T shape may be beneficially used in place of the angle shown and described. One-half of the T crossbar can then be extended between side and end panels to maintain the desired gap in place of the tabs 49.
A side bracket for an open center-forming system is shown in FIG. 14 where the bracket 39 has an upright strap element 57 with an angle support 61 fastened thereto in position to provide the strap extension 62. Paired openings 63 are again provided so that the side bracket may be applied and held at different elevations as desired. The nails 44 used to hold the open center brackets are in general easily removed by initial prying action directed against the strap or brackets or by hammer blows directed against a portion of the bracket extending below the soffet forms 24. After the brackets are initially loosened, a hammer may be used to pull the nails, and the brackets can be completely removed. As soon as the brackets are removed the form pieces 26, 36 and 27 can be easily parted from the cured concrete.
The brackets 28 and 29 as used with an open center system obviously have advantages in addition to the adaptability for use to provide pan elements of different depth. On an open center system all the support brackets and all the pan elements may be removed without disturbing the soffet boards 24 or the upright supports or shores therefor. Accordingly, on any job where roof or floor decks are to be poured in sections or at different levels, the pan panel elements may with this system be removed as soon as the concrete has taken an initial set. Removed panel elements and support brackets can, accordingly, be used for frequent pouring operations, and the contractor is thus required to provide and use a lesser number of pan components than would otherwise be required. The adaptability for frequent reuse substantially reduces the overall cost of pan components without any increase in the cost of labor for installation and removal.
As previously mentioned, the gap separating otherwise contacting elements of the pan system facilitates such early removal of the pan form elements. In most building construction operations using this system, the pan form elements of an open center installation could usually be removed within 24 hours after the concrete has been poured without danger of floor collapse. The main weight of the floor slab will still be supported by the in-place and undisturbed shores and soffets.
Form stripping operations may be further expedited where an open center type of forming as shown in FIG. 8 is used. In this modified system the plywood side panels 26 and end panels 36 extend downwardly past the soffet boards 24. The corner brackets 28 and side brackets 29 are then nailed in place by nails extending through the panels 26 and 36. These panels may be stripped without disturbing the soffets 24 or any clips 32. Panels of one size may be used to form voids of various depths by allowing any excess of panel height to extend past and below the soffet.
A different type of clip 64 is presented in FIG. 10 for use with open center forming operations. The clip 64, as used in FIG. 8, may be applied to the soffet boards 24 or to the surface of the panels so that the channel segments 66 of the clip are disposed inwardly when the extension pieces 67 are engaged against the edge of a soffet board or panel. The channel segments can then support a spreader board 68 that extends between the side panels 26 and up to the level of the bottom surface of the top panel 27. This spreader 68 helps to support any long span side panels 26 or top panels 27.
FIGS. 6 and 9 illustrate preferred installation patterns for waffle pan or two way forming systems. In order to facilitate the stripping of the pan components, it is desirable that the side and end panels be placed in the continuous series shown where each board extends past the end of the adjacent board. With this arrangement the tabs 49 on the brackets 28 or 38 will be in proper position to create the vertical gaps 33. Further, once the brackets are removed the pan upright elements can be more easily removed when this type of overlapped relationship is used.
For uninterrupted long span designs, as shown in FIGS. 5 and 8, corner brackets 38 can be provided in which the tabs 49 are extended in opposite directions to obtain the arrangement of elements as illustrated in these FIGS. With long span installations, no difficulty is experienced in the removal of end or side panels where this modified type of installation arrangement is used. Necessarily, the overlapping arrangement of FIGS. 6 and 9 as described can be used for even the long span elements.
In addition to use of the invention in connection with the building of pans for the formation of voids in concrete floor and deck construction, the teachings of the invention are adaptable for use in the forming of other concrete structural elements. In any poured concrete structure that has an inside corner and in connection with the forming of which there is a possibility that the form elements could become trapped in the poured concrete, use ofa supporting bracket having an extension element or component extending between otherwise contacting form panels is recommended. Where paired inside corners are to be formed and where the corners are spaced apart a distance corresponding to the width of a single form element or panel, the establishment of one or more gaps is desirable to facilitate form removal.
While the use of tape to keep concrete from escaping from the forms is recommended, it should be noted that the system has utility under circumstances where no tape is used and where some of the concrete escapes through the gaps 33. In general, if the gap is of width less than the size of the fine gravels used in the concrete aggregate, the loss of material when the concrete is poured will be within operational limits. Since gravel aggregates are often considered to include all materials retained on a No. 4 screen, the finest gravels would have a particle size of at least three-sixteenths of an inch. The gap 33 should, accordingly, be of this size or smaller.
For the purposes of this disclosure, the terms gap or slight gap are used to designate an opening of size less than the size of the fine gravels used in the concrete admixture if tape or some other gap occluding element is not set forth. Where the gap is bridged or occluded, wider openings may be used without departure from the teachings of this invention. The concrete materials that do escape into a nonoccluded gap and that are retained therein have little strength due to the thin cross section. Accordingly, the forms can still be removed after the concrete has set. In practice it has been found that the use of a gap occluding element is preferred, since the pouring operations will be cleaner and the forms may be more readily stripped.
1. A forming system for use in the construction of poured concrete structural elements having inside corners comprising panel members disposed in intersecting planar relationships to provide a lap joint corner, support brackets disposed inwardly of said panel members and away from concrete being poured for contacting at least two such intersecting panel members to hold said panels in operative concrete excluding positions, and extension elements on said brackets extending between panel members in otherwise butting contact at said lap joint for maintaining a slight gap therebetween to facilitate removal of said panel members after the concrete has set.
2. Structure as set forth in claim 1 wherein paired inside comers are to be formed in spaced-apart relationship not greater than one panel width and three panel thicknesses apart.
3. Structure as set forth in claim 1 and further comprising a gap occluding element to prevent intrusion and escape of poured concrete into and through said gap.
4. Structure as set forth in claim 1 wherein said system is used to provide pan forms for the creation of voids in concrete decks and floors that are to be poured above supporting false work form elements and wherein said panel members are inclusive of side and top panel elements.
5. Structure as set forth in claim 4 wherein a plurality of brackets are used with each bracket being disposed in contacting relationship with side and top panel elements and wherein said extensions are positioned to maintain a gap between said side and top panels.
6. Structure as set forth in claim 5 wherein said brackets have a standard component disposed in upright position, and further comprising platform support elements on said standard for engaging and holding said top panels in elevated position.
7. Structure as set forth in claim 6 wherein said extension element is provided by a portion of said standard raised and extending above said platform support.
8. Structure as set forth in claim 7 wherein said extension element is extended above said platform a distance less than the thickness of said top panels.
9. Structure as set forth in claim 4 wherein said supporting false work form elements are of the solid deck type and wherein said brackets are disposed in upright position above said solid deck to hold the side and top panels ofthe pan forms in operative position.
10. Structure as set forth in claim 1 wherein said panel members are disposed to form paired inside corners with at least one panel extending between said corners and subjected to longitudinal compressive stress exerted by poured concrete with said longitudinal compressive stress being transmitted to and by an end of an intersecting panel 1]. Structure as set forth in claim 4 wherein said supporting false work form elements are of an open center type and wherein said brackets are disposed in upright position to extend to a side edge of said open center false work form elements to hold the side and top panels of the pan forms in operative position.
12. Structure as set forth in claim 11 wherein said side panels are aligned to extend into the open center of said false work form elements.
13. Structure as set forth in claim 11 wherein said side panels and brackets are aligned to extend into the open center of said false work form elements whereby said brackets and side panels may be positioned at adjusted elevations with respect to said false work forms.