TRUSS ASSEMBLY

Abstract: The present invention discloses a new concrete forming system and components therefor, particularly adapted for forming of vaulted ceilings and for use in buildings wherein the floors at the edges thereof have upwardly extending sills and/or wherein the ceilings have been dropped by a similar ledge or sill thereby significantly reducing the clear area through which a truss can be removed. The truss comprises a top chord and a bottom chord interconnected by upright members and diagonal bracing members. A number of adjustable extension legs are associated with the upright members and are telescopically received within an upright member such that a leg extending to the upper side of the truss can overlap with a leg extending to the lower side of the truss, whereby the legs extending above the truss can be adjusted and maintained independent of the legs extending below the truss. In contrast to the prior art practise of having the upper chord of the truss at the lowest level of the ceiling with "packing" thereabove to define and support the con­ crete forming surface. The present system provides load collecting support beams adjustably secured above the upper chord of the truss by extendable legs whereby the position of the support beam can vary relative to the top chord of the truss. The height of the truss is used to accommodate the extendable legs which position the truss above the floor as well as the extendable legs supporting the load collecting beam, whereby the amount of packing and the time required to initially set up the system for a given building are reduced. Therefore, the present invention relates to improvements in flying forms and components thereof and in particular to a system which is more flexible and adjustable for the forming of vaulted ceilings.

Description: BACKGROUND OF THE INVENTION The present invention relates to forms and components thereof for use in concrete forming and in particular, forms and components thereof which include trusses for forming of concrete floors. The forms preferably are of the type that are adapted to be lifted by crane between floors of a building during the construction thereof, thereby substantially reducing the time required to set up the form for pouring of the next floor. In particular, the invention is directed to forms which provide additional flexibility and convenient adjustment to define a system for forming of ceilings of different heights or vaulted ceilings. Flying forms, which are essentially a number of interconnected truss structures adapted to be moved on rollers or the like beyond the building and lifted to the next floor, greatly reduce the required labour necessary for set-up of the forms. Forms of this type include United States Patent 4,077,172, United States Patent 3,966,164, United States Patent 3,787,020 as but some examples. Recent architectural design to provide additional strength has used concrete ceilings provided with concrete beams which require a stepped ceiling. It is also common to provide a concrete sill at the edge of the floor and a downwardly extending edge portion from the ceiling to reduce the window size. Such structures present additional problems as "packing" is required on the top surface of the truss to accomodate the changing heights of the ceiling. This "packing" is commonly made of wood and beams and as such is very labour intensive and costly. The amount of"packing" can be quite substantial as the top chord of the truss can only be located below the lowest position of the ceiling. When the truss is collapsed for movement between floors, by the lower legs being retracted within the truss, the effective height of the truss is the extent to which the legs may extend below the truss, the height of the truss and the height of any "packing" material secured above the truss. Often this effective height is such that flying forms cannot be used due to the reduced clear area between the concrete sill and downwardly extending ceiling edge. A further prior art is AT-B-324 663. In this document there is disclosed a four legged support structure, these four legs being interconnected by diagonal and horizontal bracing members. In the bottom of each leg there is mounted a lower extendable member whereby the whole structure can be adjusted in height. In the top of each leg there is mounted an upper extendable member, these upper extendable members being co-axial with the lower extendable members and serving to support a pair of spaced apart beams on which a support surface for accepting a poured concrete floor may be laid. There is no indication that the horizontal bracing means are intended to carry any load therealong. The present invention resides in a truss, as defined in the accompanying Claim 1, for use in a concrete forming. The invention is also directed to an upright member, as defined in the accompanying Claim 12, for use in a concrete forming truss. The invention is also directed to a system for concrete forming as defined in the accompanying Claim 17. BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are shown in the drawings, wherein: Figure 1 is a partial perspective view of a truss used in concrete forming; Figure 2 is a partial perspective view of a portion of a truss illustrating the co-operation of the upright support members with the top and bottom chords of the truss; Figure 3 is a partial perspective view showing additional details of the co-operation between the upright member and the top and bottom chords of the truss; Figure 4 is a partial front view of the concrete forming system showing a partial section of a vaulted ceiling; Figure 5 is a partial front view of a portion of the truss system adapted for forming of a ledge at the edge of the floor; Figure 6 is view similar to Figure 5 with the truss in its retracted state for removal from between concrete floors. Figure 7 is a partial cut-away perspective view of the truss system with a modified construction; Figure 8 is a top view of the modified upright; and Figure 9 is a partial sideview of the modified upright. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete forming system generally shown as 2 in Figure 1 has parallel trusses 3 and 4, each having a top chord member 6 and a bottom chord member 8, spaced by upright members 10 and truss diagonal braces 12. The trusses are interconnected by the braces 14. Load collecting beams 22 preferrably run parallel with the top chord 6 of each truss or perpendicular to the top chords 6. The sheeting material 20 is secured atop the beams 18 and at least partially defines the concrete form. A number of trusses 6 can be interconnected for forming larger areas and can be moved as a unit depending upon the construction site and the crane capacity. In the system shown in Figure 1, 3 different concrete forming levels are shown for accomodating concrete beams and stepped areas formed as part of the floor. Load collecting beams 22 are appropriately positioned by extendable legs 24 or screw jacks as shown, of a size for receipt within an upright member 10. Extendable legs 26 are positioned adjacent the bottom edge of the truss, support the truss at the required height above a support floor. Therefore, the truss, defined between the top chord member 6 and the bottom chord member 8, is positionable at various spacings above a support floor by adjusting the lower extendable legs 26. Extendable legs 24 allow for fast positioning of load collecting beams 22, in accordance with the desired ceiling profile. The legs 24 and 26 are telescopically received within the upright members 10 without interference between leg 24 and 26. This occurs as the legs are adjacent to each other and each upright member 10 has the capacity for receiving two legs. This in effect allows the maximum height of the concrete forming system to be substantially increased relative to the spacing between the top chord 6 and the bottom chord 8 and results in a more efficient and flexible system as the amount of "packing" required has been reduced and the ability to easily define different concrete support levels has been improved. In the system as shown in Figure 1, "packing" 29, illustrated as 2 x 4's (2 x 101,6 mm) nailed to the sheeting material 20, is provided at each change in level of the form. The packing for a given level has been replaced by load collecting beams 22 supported by legs 24. Normally it will not be necessary for all uprights 10 to receive extendable legs and some may merely act as a structural member such as upright 10a. Details of the telescopic receipt of extendable leg 24 and extendable leg 26 within one of the upright members 10 can be appreciated from Figure 2, where upright member 10 has two opposed members 32 and 34, each of a size for receiving an extension leg. Webs 36 and 38 in combination with members 32 and 34, define a closed cavity 40. This cavity is advantageously used to receive bolts 92 for connecting the upright member 10 to the chord members 6 and 8. As the bolts pass through the cavity 40, the hollow portion within each of the tube members 32 and 34 remains clear and allows extendable legs 24 and 26 to collapse or telescope within the full length of each tube member. To the exterior of web members 36 and 38, bolt slots 42 and 44 are provided. Bolt slot 42 has exterior flanges 46 and 48 which define a planar face for engaging the interior surface of the side plate 62 of the bottom chord member 8 and the interior surfaces of the side plate 82 of the top chord member. Bolt slot 44 includes similar flanges and cooperates with side plates 64 and 84. In addition each tube member includes opposed thickened portions 50 and 52 having a planar outer face. The face of portions 50 are co-planar with flanges 48 and 46 which also engage the interior surface of the bottom chord member and the top chord member to provide a more secure fit of the upright member within the chord members. Portion 52 cooperates with the flanges of bolt slot 44 to engage the opposite side plates of the top and bottom chord. The bolts 92 pass through the side plates of the chord members and through the bolt slots to apply the pressure adjacent these planar engaging faces to increase the structural integrity of the system. The uprights are preferrably extruded of a magnesium or aluminum alloy although not limited thereto. The top chord member 6 includes a top plate 80 which extends beyond the side plates 82 and 84 to define downwardly extending lips 86, either side of the longtitudal axis of the top chord member 6. These lips 86 are used for clamping of additional components to the top chord member. The top plate 80, includes a circular opening 81 to allow access to the hollow interior portions of the tube members 32 and 34 whereby the extendable leg 24 can be received in either of the tube members 32 and 34. The bottom chord member 8, is open on the bottom and as such the hollow interior portions of tube members 34 and 36 are exposed at the bottom of the chord member. However, the bottom chord does include inwardly extending lips 66 and 68, which bearingly engage with the lower surfaces of the thickened portions 50 and 52 and the lower portion of the bolt slots 42 and 44. The top plate 60 of the bottom chord member has an aperture therein for receiving the upright member 10, which is held within the bottom chord member by the bolts 92. The lips 66 and 68 reduce the shear stress that must be carried by the bolts 92. The bottom chord member also includes outwardly extending lips 70 and 72 having the edge thereof flared upwardly. This lip arrangement is used for securing of components to the bottom chord member and increases the stiffness of the bottom chord member. The top chord member 6, the bottom chord member 8 and the upright members 10, are preferrably extruded of a light weight alloy of aluminum or magnesium although a version of the system made of steel can be used if the increased weight can be accomodated. The extendable legs 24 and 26 can be of many different forms and the form shown for leg 24 includes a support plate 94, having a externally threaded stub tube 100, having a rotatable member 101, thereabout. The leg 24 includes an extension leg rod 95, having a number of holes 102 therein, for receiving the pin member 96. Therefore, the leg is roughly adjusted according to the length required, by proper placement of pin member 96 in one of the holes 102 and member 101 is then adjusted to more accurately position the channel bracket 74 which supports the load collecting beam 22. In this case, the extension leg rod 95, is telescopically received within tube member 34 and the extension rod member 105 of the lower leg is telescopically received within tube member 32. Rod 95 and rod 105 will overlap when the system is arranged in its most compressed or compacted state. A similar type leg arrangement 104, has been shown at the bottom edge of the bottom chord 8, however, these legs are but examples of what can be used and the invention is not limited to these legs. The important point to note, is that the position of the extendable leg rods 95 and 105 intermediate the top chord 6 and the bottom chord 8 can overlap and, therefore, the effective maximum height of the system without considering screw jacks etc securable to the legs is generally significantly greater than twice the spacing between the bottom chord 8 and the top chord 6. The lower leg can be fully received within the truss when the system is "compacted" independent of the amount of upper leg received within the truss. Figure 3 shows a similar type arrangement, however, in this case the tube members 32 and 34 of the upright member 10 have a number of holes 110 through the thickened portions 50 and 52 which are alignable with holes 112 of leg 24a and 104a. A locking U-bar 108 is receivable in adjacent holes 110 of the upright member 10 for passing through holes 112 in the leg 24a or 104a for providing a rough adjustment of the position of the channel bracket 74 above the top chord member 6 or for spacing of the support plate 106, a certain distance below the bottom chord member 8. More accurate adjustment is achieved by turning of the threaded collars 113 of leg 24a or collar 115 of leg 104a. In contrast to the structure of Figure 2 top plate 80 has a somewhat elongate opening 117 to allow leg 24a to telescope within the hollow interior of tube member 32. This allows the user to position leg 24a to telescope within tube 32 or within tube 34 and appropriately position the bottom leg to telescope within the other tube. Therefore, in the preferred embodiment both tubes 32 and 34 are opened to the upper side of the top chord 6, and are opened to the lower periphery of the bottom chord 8. The elongate opening 117 is not oversized and, therefore, the thickened portions 50 and 52 of each upright member 10 will engage the underside of top plate 80 and similarly the bolt slots 42 and 44 will also engage the top plate. The advantage of two openings rather than one elongate opening 117, is that the portion of the upper chord generally between the tubes remains intact and provides additional bearing surface for upright 10. Figures 4, 5 and 6 illustrate how the concrete forming system of the present application can advantageously be employed. In Figure 4 a portion of a vaulted ceiling 120 is shown, where load collecting beam 22b supports beam 18b which in turn supports the sheeting material 20b for defining a portion of the form defining the multi-level ceiling. Beams 18c can be directly supported on the top chord member 6 of the truss and support sheeting material 20c for defining the lower surface of the ceiling. Load collecting beam 22a supports beams 18a and sheeting material 20a for defining another step in the ceiling. In addition, sheeting 20d and 20e are shown deleting the vertical surfaces of the vaulted ceiling and nailed to the upper and lower level via a number of 2 x 4's. When it is desired to remove the system 2 from between the lower floor 200, the lower legs 26 are essentially fully telescoped within the upright members 10 and the legs 24a and 24b preferrably remain at their adjusted position with a certain portion thereof within the upright member 10. Thus the surface 20b, 20c and 20a and any packing will maintain their position relative to the top chord member 6. The system is most effective when the truss is of a height whereby the legs 26 and associated jack screw are close to fully extended whereby the system can pass through a gap slightly larger than the truss and the structure thereabove defining the concrete forming surface. If the height is still too great, packing for surface 20e and 20d may be removed and legs 24a and 24b telescoped within the truss. Normally this is not required but is advantageous in that the ability of the system to move through a narrow space is further increased. In Figures 5 and 6, the system is shown supporting a portion of the concrete floor adjacent the edge of a building. In this case, the floor of the building has a bottom sill 126 projecting upwardly therefrom, and a downwardly projecting portion 124 which extends below the lower surface of the newly poured floor 122. Therefore, the gap between portion 124 and 126 is defined by the spacing "A", and as such the system must compress or collapse to a height less than the spacing "A" to allow the truss to be moved as a unit outwardly through the gap "A" to allow flying of the form to the top surface of the newly poured floor 122. In Figure 5, it can be seen that end 27 of leg 26 and end 25 of leg 24, are positioned such that there is an overlap between legs 24 and 26. In this case, the full height capacity of the system was not required. From a consideration of Figure 6, it can be seen that the end 25 remains at the adjusted position within the upright member 10 and end 27 telescopes to move to be adjacent the top chord 6. Therefore, the ability of the system to compress is independent of legs 24 as each leg 24 and 26 moves independently within the upright member 10. The overall height of the truss can greatly be reduced in its compressed state by telescopic receipt of legs 24 in the truss. This provides a ratio of maximum height of the combined truss and legs independent of jack screws relative to minimum height substantially greater than two and up to about three. This is particularly advantageous in the present design of buildings as it is desirable to have vaulted-type ceilings with downwardly extending ledges where the actual space for moving of the truss exterior of the building has been substantially reduced. A modified structure is shown in Figures 7 through 9, which can be fabricated from commonly available components. The upright 210 has two spaced square tube members 234 and 236 secured and spaced by plates 242 and 244 to define cavity 240 intermediate the tube member 234 and 236 and the top chord 204 defined by opposed channels 205 and 206. Plates 242 and 244 are preferrably welded to tube members 234 and 236. The bottom chord 208 defined by channels 207 and 209, is similiarly attached to the upright 210 secured either side by plates 215 and 217. Bolts 292 pass through the channels and the plates to secure upright 210 to the bottom chord 208 and the top chord 204. The use of tubes 234 and 236 of square or rectangular section is preferred as welding of plates 242, 244, 215 and 217 thereto is simplified. It is also possible to use tubes of other cross section such as circular and oval although securement to the top and bottom chord is slightly more difficult. The use of welded plates as above will adequately secure the chords to the upright member.

Claims: A truss (3, 4) for use in concrete forming comprising a top chord (6) and a bottom chord (8) interconnected by upright members (10) and diagonal bracing members (12); at least some of said upright members (10) having two individually telescopically adjustable extension legs (24, 26); one extension leg (24) being at one end of its upright member for supporting a load exerted thereon and the other extension leg (26) being at the other end of said upright member for supporting said truss; characterized in that each upright member (10) comprises paired upright members (32, 34); one of the paired members (32) having at its upper end one of said two extension legs (24), and the other of the paired members (34) having at its lower end the other of said two extension legs (26). each extension leg (24, 26) being of a length substantially greater than half the length of its associated upright member (32, 34); the arrangement being such that each of the two extension legs (24, 26) of an upright member (10) can, at the same time, be in a retracted setting in the upright member, each by an amount greater than half the length of the upright member. A truss according to Claim 1, charcterized in that the paired members (32, 34) of an upright member (10) are two tubes (32, 34) connected to each other by webs (36, 38) defining in association with the two tubes (32, 34) an enclosed cavity (40) running the length of the upright member (10). A truss according to claim 2, characterized in that said webs (36,38) are opposed and each partially defines bolt slots (42,44) to either side of and exterior to said cavity (40) running in the length of said upright members (10). A truss (3,4) according to claim 2, characterized in that each tube member (32,34) includes two planar faces (50,52) for engaging opposite interior areas of each of said top (6) and bottom chords (8). A truss (3,4) according to claim 2, characterized in that said top chord (6) has a channel open towards said bottom chord (8) which receives said paired upright members (10), and said bottom chord (8) has a planar top surface (60) and a channel open on the bottom of said bottom chord (8), said channel of said bottom chord (8) including lips (66,68) partially closing a lower edge of said channel of said bottom chord (8) for bearingly supporting an end of said paired upright member (10) which passes through an opening in said top surface (60) of said bottom chord (8) and engages said lips (66,68) either side of said channel of said bottom chord (8). A truss (3,4) according to claim 4, characterized in that said webs (36,38) are opposed and each partially defines bolt slots (42,44) to either side of and exterior to said cavity (40) and orientated in the length of said upright member (10), each of said bolt slots (42,44) having an exterior planar face (46,48) running the length thereof which is co-planar with one of the planar faces (50,52) on each extension means (24,26) all of which engage an interior area of said top (6) and bottom chord (8) members, said interior areas of said top (6) and bottom chord (8) being brought into pressing engagement with said planar faces (46,48,50,52) by tightening bolts (92) which pass through said top (6) and bottom chord (8) members generally perpendicular to the length thereof and pass through said closed cavity (40) of each upright member (10), each upright member (10) at the ends thereof bearingly engaging said top (6) and bottom chord (8) members to reduce the shear force carried by said bolts (92) when said truss (3,4) is loaded. A truss according to claim 1, characterized in that said certain upright members (10) each include two elongate hollow tubes (32,34) each for receiving an extension means (24,26). A truss (3,4) according to claim 7, characterized in that each extension means (24,26) has a cross section to permit telescopic movement of said extension means (24,26) within an associated hollow tube (32,34) with said tube limiting substantial lateral movement of said extension means (24,26) within said tube. A truss (3,4) according to claim 8, characterized in that said hollow tubes (32,34) of each upright member (10) are interconnected by web means (36,38). A truss (3,4) according to claim 9, characterized in that said upright members (10) are extruded of an aluminum alloy. A truss (3,4) according to claim 1, characterized in that a structural chord member (6,8) of an extruded light weight aluminum or magnesium alloy, said structural member in cross section comprising a top plate (60,80), two side plates (62,64,82,84) generally perpendicular to said top plate (60,80) and disposed intermediate the width of said top plate (60,80) to define lip regions (86) either edge of said top plate (80) beyond said side plates (82,84), each of said side plates terminating in bottom flanges which extend outwardly, each bottom flange being at the same spacing from said top plate (60) and having an upwardly extending lip (70,72) beyond the associated side plate (62,64) to provide a 'U' shaped recess for engaging clamping components intermediate said associated side plate (62,64) and said upwardly extending lip (70,72), each of said bottom flanges including an inwardly extending lip (66,68) region intermediate said side plates (62,64) which provide opposed bearing surfaces for engaging either side adjacent the end of a further structural member which passes through said top plate (60). An upright member (10,210) for use in a concrete forming truss (3, 4) having a top chord (6) and bottom chord (8); the upright member having two individually adjustable extension means (24, 26); one extension means (24) being at one end of the upright member and the other extension means (26) being at the other end of the upright member; characterized in that the upright member (10) comprises two members (32,34;234,236) disposed in parallel relationship and of a size and shape for slidably receiving, at the same time, each of the two adjustable extension means (24, 26) by an amount up to a length greater than half the length of the upright member; there being means for limiting lateral movement of retracted portions of the extension members (24, 26) within upright member (10), and connecting means capable of transferring supporting load between said two members disposed in parallel relationship. An upright member (10) according to claim 12, characterized in that said connecting means is a web (36,38) portion generally intermediate said two opposed portions. An upright member (10) according to claim 12, characterized in that said member is of a shape for telescopically receiving extension means (24,26), said members being interconnected by web means (36,38) between said members, each of said members including generally planar opposed parallel bearing surfaces (46,48,50,52), each bearing surface on one member being colinear with a bearing surface on the other tube member. An upright member (10) according to claim 13 or 14, characterized in that said web means (36,38) includes opposed webs which define a generally closed cavity (40) between said webs (36,38) and said members (32,34). An upright member (10) according to claim 15, characterized in that said members each define a circular hollow core for receiving a leg extension or jack screw (24,26) and wherein bolt slots are (42,44) provided to either side of said opposed web members (34,38) intermediate said members. A system (2) for concrete forming comprising at least two trusses (3, 4) interconnected to maintain the relative positions thereof; each truss (3,4) having a first set of extension means (26) telescopically associated within upright members (10) of each truss (3,4) for positioning the truss at a height above a support surface (200); and having a second set of extension means (24) telescopically received within said upright members (10) of each truss (3,4) for supporting means for forming a concrete support surface at various heights above said truss (3,4); characterized in that each upright member (10) comprises paired upright members (32,34); one of the paired members (32) having at its upper end one of said two extension legs (24), and the other of the paired members (34) having at its lower end the other of said two extension legs (26) each extension means (24, 26) being of a length substantially greater than half the length of its associated upright member (10); the arrangement being such that each of said extensions means (24, 26) associated with an upright member (10) can, at the same time, be in a retracted setting in the upright member, each by an amount greater than half the length of the upright member; the first set of extension means (26) of each truss being of such a length that they can be extended to position said truss above a support surface (200) up to about the height of the truss; and said upright members (10) are such as to permit vertical overlap of said first and second extension means (26, 24) in preparation for moving said system (2) to a different level. A system (2) according to Claim 17, characterized in that said upright members (10) are hollow and receive said extension means (24, 26) therewithin, said extension means (24, 26) and the hollow of said upright members (10) being of a complementing shape to permit sliding extension means (24,26) movement and limit extension means movement laterally within said upright members (10). A system (2) according to claim 17, characterized in that said second set of extension means (24) are adjustable legs adapted to support load collecting beams and permit adjustment of said load collecting beams (22) above said trusses (3,4), the load collecting beam (22) of one truss (2,4) being connected to a load collecting beam of the other truss (3,4) by a plurality of joists (18) which support said support surface, said second set of adjustable legs (24) being telescopically received within said trusses (3,4) to permit said load collecting beams (22) to be generally immediately adjacent said trusses (3,4) for moving of the system (2) when necessary. A system (2) according to claim 18 or 19, characterized in that said trusses (3,4) are parallel opposed, each of said trusses (3,4) including a top chord (6) and a bottom chord (8) interconnected by said upright members (10). A system (2) according to claim 18 or 19, characterized in that said upright members (10) including two parallel elongate members (32,34) extending between said top (6) and bottom chord (8) with said members secured to the top and bottom of said truss for telescopically receiving extension means (24,26) extending above and below said truss (3,4).

Inventors: JOHNSON, RONALD J.
Applicants: ALUMA INTERNATIONAL
Application year: 1985
Main classification: E04G11
IPC codes: E04G11