Slab formwork systems

Abstract

A slab formwork system for casting ceilings has panel support beams underlying and supporting formwork panels; and shores supporting the panel support beams. The panel support beams have upwardly facing top surfaces with upwardly open, longitudinally extending recesses and resiliently deformable strips of elastomeric material extending along the recesses. The formwork panels having marginal edge undersurface portions mounted on the panel support surfaces and downwardly protruding panel retainer projections embedded in the resiliently deformable strips. The formwork panels each have a pair of parallel, elongate intermediate members extending between and interconnecting parallel elongate side members and a sheet of material supported on the side and intermediate members, and the side members have undersides formed with a longitudinally extending, downwardly open recesses. Connecting clips retained in the downwardly open recesses are engaged with the support beams to secure the formwork panels to the support beams. The panel support beams are telescopically longitudinally adjustable to allow corresponding variation of the spacings of the shores which have dropheads each having a first component forming a prophead extending between an adjacent pair of the formwork panels and a second component in supporting engagement with the formwork panels. The first and second components have mutually engaged screw threads allowing the second component to be lowered relative to the first component for releasing the formwork panels.

1 . A slab formwork system, comprising: 
 formwork panels;    panel support beams underlying and supporting the formwork panels; and    shores supporting the panel support beams;    the panel support beams having upwardly facing top surfaces; upwardly open, longitudinally extending recesses between the top surfaces and resiliently deformable strips of elastomeric material extending along the recesses; and    the formwork panels downwardly protruding panel retainer projections embedded in the resiliently deformable strips.    
   
   
       2 . A slab formwork system has claimed in  claim 1 , wherein the panel retainer projections are tapered so as to urge adjacent pairs of the panels towards one another as the panel retainer projections become embedded in the strips.  
   
   
       3 . A slab formwork system has claimed in  claim 1 , wherein the beams have pairs of flanges spaced apart by gaps, the recesses being upwardly open through the gaps, and wherein the gaps are closed by the resiliently deformable strips.  
   
   
       4 . A slab formwork system as claimed in  claim 3 , wherein the flanges are shaped, within the recesses, to interfit with and retaining the resiliently deformable strips.  
   
   
       5 . A slab formwork system as claimed in  claim 1 , including connectors securing the formwork panels to the panel support beams.  
   
   
       6 . A slab formwork system as claimed in  claim 5 , wherein the panel support beams have laterally outwardly projecting flanges and the contactors comprise connector strips secured to the formwork panels and engaging the outwardly projecting flanges.  
   
   
       7 . A slab formwork system as claimed in  claim 1 , wherein the formwork panels have elongate side members formed as extrusions, the extrusions have longitudinal, downwardly open recesses and the panel retainer projections extend from ends of the downwardly open recesses.  
   
   
       8 . A slab formwork system as claimed in  claim 7 , including connectors engaged in the downwardly open recesses and in retaining engagement with the panel support beams.  
   
   
       9 . A slab formwork system, comprising: 
 formwork panels;    the formwork panels each having a pair of parallel, elongate side members, elongate intermediate members extending between and interconnecting the side members and a sheet of material supported on the side and intermediate members;    the side members having undersides formed with a longitudinally extending, downwardly open recesses:    support beams carrying the panels; and    connecting clips retained in the downwardly open recesses and engaged with the support beams to secure the formwork panels to the support beams.    
   
   
       10 . A slab formwork system as claimed in  claim 9 , wherein the connecting clips include bolts having heads retained in the downwardly open recesses and U-shaped retainer members secured to the framework panels by the bolts, the panel support beams having laterally outwardly projecting flanges and the retainer members being held in clamping engagement with the outwardly projecting flanges.  
   
   
       11 . A slab formwork system as claimed in  claim 9 , including panel retainer projections extending from the downwardly open recesses into engagement with the panel support beams.  
   
   
       12 . A slab formwork system as claimed in  claim 11 , wherein the panel support beams have upwardly open recesses in the tops of the panel support beams and the panel retainer projections engage in the upwardly open recesses.  
   
   
       13 . A slab formwork system, comprising: 
 formwork panels;    panel support shores spaced from one another;    panel support beams underlying the formwork panels and supported by the shores;    the panel support beams being telescopically longitudinally adjustable to allow corresponding variation of the spacings of the shores.    
   
   
       14 . A slab formwork system as claimed in  claim 13 , wherein the panel support beams have telescopically extendable extension members and fasteners for securing the extension members relative to the panel support beams, the dropheads having bearing members for supporting engagement with the extension members.  
   
   
       15 . A slab formwork system, comprising: 
 formwork panels;    panel support beams;    panel support shores;    the shores having dropheads and the dropheads each having a first component, the first component having a prophead between an adjacent pair of the formwork panels and a second component in supporting engagement with the formwork panels; and the first and second components having mutually engaged screw threads allowing the second component to be lowered relative to the first component for releasing the formwork panels.    
   
   
       16 . A slab formwork system as claimed in  claim 15 , wherein the first component comprises a screw and a nut in threaded engagement with the screw, the prophead being at an upper end of the screw, and the second component comprises a sleeved extending around the screw and supported on the nut, first beam supports projecting from opposite sides of the sleeve and supporting the panel support beam and second beam supports projecting to opposite sides of the sleeve at right angles to the first beam supports, the slab formwork system further comprising filler beams extending between the formwork panels and supported on the second beam supports.  
   
   
       17 . A slab formwork system, comprising: 
 formwork panels;    panel support beams underlying and supporting the formwork panels; and    shores supporting the panel support beams;    the panel support beams having upwardly facing top surfaces; upwardly open, longitudinally extending recesses in the top surfaces and resiliently deformable strips of elastomeric material extending along the recesses;    the formwork panels having marginal edge undersurface portions mounted on the panel support surfaces and downwardly protruding panel retainer projections embedded in the resiliently deformable strips;    the formwork panels each having a pair of parallel, elongate side members, elongate intermediate members extending between and interconnecting the side members and a sheet of material supported on the side and intermediate members; and    the side members having undersides formed with a longitudinally extending, downwardly open recesses;    connecting clips retained in the downwardly open recesses and engaged with the support beams to secure the formwork panels to the support beams;    the panel support beams being telescopically longitudinally adjustable to allow corresponding variation of the spacings of the shores;    the shores having dropheads, the dropheads each having a first component forming a prophead extending between an adjacent pair of the formwork panels and a second component in supporting engagement with the formwork panels; and    the first and second components having mutually engaged screw threads allowing the second component to be lowered relative to the first component for releasing the formwork panels.