Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B7/00—Moulds; Cores; Mandrels
  • B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials

Definitions

• This invention relates to moulds for the casting of cementitious mate ⁇ al and more particularly to coffers used for the casting of coffer slabs
• coffers are widely known to provide slabs with strengthening ribs integral with and projecting from the underside of the slab These ribs are often specially used for architectural aesthetic appearance as well as for their functionality
• the coffers which have been used for many years are either fabricated from steel plate or moulded from glass fibre reinforced resin
• the former are necessarily heavy constructions which in practice have had to be fitted with specially formed corner plates in order to provide proper casting and finish to the slabs where these coffers are used
• the coffers are thus expensive and heavy to manipulate
• the glass fibre reinforced resin coffers are readily subject to damage This spoils the surface on which the cementitious material is cast with consequent degrading of the finish of the cast slab Serious damage by cracking through the coffers necessitates the coffer being entirely replaced OBJECT OF THE INVENTION
• edge of the recess to have a peripheral flange projecting away from the recess and for the flanges to terminate in a rib directed away from the recess
• the invention also provides for the flanges to be reinforced and to have gusset plates supporting the corners of the coffer
• Still further features of this invention provide for the flanges to be reinforced by folded angle sectioned members or by having the free ends of the ribs folded back upon itself.
• gusset plates to be triangular and of flat or folde'd plate
• the invention still further provides for the bottom of the recess to be perforated
• FIG 1 is an oblique view of one form of coffer
• FIG 2 an oblique view of an alternative embodiment
• the coffer (1) is made from mild steel plate which can conveniently be 1 2 mm thick
• the material can be a normal drawing quality mild steel such as that supplied by Iscor as "SUPRA 180" and the grid size may be 900 mm by 825 mm with a depth of 325 mm for example Sheets of this material can be deep drawn in a heavy duty die set
• the coffer will have the recess (2) centrally located in a rectangular sheet of material (3) while a peripheral flange (4) projects away from the recess (2) of the coffer
• the edge (5) of the flange (3) is folded to also project away from the recess (2) to form a rib (6)
• the flange (3) and rib (6) are supported by angled sectioned members (7) folded from similar metal and welded into position as shown
• Fig 2 the coffer is illustrated as formed from a square sheet of metal
• Reinforcement of the flange (3) around the recess is effected by having the free end of the rib (6) folded back upon itself.
• Each corner of the coffer is strengthened against damage by a triangular gusset in the form of a bracket (9).
• the reinforcing bracket (9) is folded from steel plate (as indicated in th ⁇ insert in the drawing) and subsequently welded into position
• the side walls (10) of the recess (2) can also be reinforced with either permanent braces welded into place or by braces which may be packed into place to provide the desired support
• the braces will preferably support a substantial area of the inner wall of the recess.
• One advantage of the removable support is that the walls can be allowed to flex once the cementitious mix with which the coffers are used has set. This will facilitate stripping of the coffers.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Mechanical Engineering (AREA)
• Forms Removed On Construction Sites Or Auxiliary Members Thereof (AREA)
• Rod-Shaped Construction Members (AREA)

Applications Claiming Priority (5)

Publications (1)

Family

ID=27145315

Family Applications (1)

Country Status (3)

Family Cites Families (6)

• 2000
  • 2000-05-16 EP EP00974147A patent/EP1115533A2/de not_active Withdrawn
  • 2000-05-16 AU AU14990/01A patent/AU1499001A/en not_active Abandoned
  • 2000-05-16 WO PCT/ZA2000/000096 patent/WO2000073025A2/en not_active Ceased

Non-Patent Citations (1)

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