Apparatus in and relating to building formwork

Claim 1

A building block formwork element to be used in building a structure, comprising: a. a hollow rectangular shaped block member having first and second oppositely disposed parallel side walls and first and second oppositely disposed parallel end walls; b. said first side wall containing a multiplicity of mating grooves and ribs which extend along the height of the wall; c. said second side wall containing a multiplicity of mating grooves and ribs which extend along the height of the wall; d. said first end wall containing a multiplicity of mating grooves which extend along the height of the wall; e. said second end wall containing a multiplicity of ribs which extend along the height of the wall and correspond to the multiplicity of mating grooves in the first end wall; f. said second end wall containing a multiplicity of mating grooves which extend along the height of the wall; g. said first end wall containing a multiplicity of ribs which extend along the height of the wall and correspond to the multiplicity of mating grooves in the second end wall; h. the ribs and grooves in said first and second end wall also corresponding to selected grooves and ribs in said first and second side walls; i. said first end wall containing an upper arcuate cut-out portion extending downwardly from its top and a lower arcuate cut-out portion extending upwardly form its bottom; j. said second end wall containing an upper arcuate cut-out portion extending downwardly from its top and a lower arcuate cut-out portion extending upwardly from its bottom; k. a first upper removable insert member corresponding to the upper arcuate cut-out portion of said first end wall and removably inserted therein; l. a first lower removable insert member corresponding to the lower arcuate cut-out portion of said first end wall and removably inserted therein; m. a second upper removable insert member corresponding to the upper arcuate cut-out portion of said second end wall and removably inserted therein; n. a second lower removable insert member corresponding to the lower arcuate cut-out portion of said second end wall and removably inserted therein; o. the top of said first side wall containing a longitudinal ridge extending the length of the wall; p. the bottom of said first side wall containing a longitudinal groove extending the length of the wall and corresponding to the ridge on the top of the wall; q. the top of said second side wall containing a longitudinal ridge extending the length of the wall; r. the bottom of said second side wall containing a longitudinal groove extending the length of the wall and corresponding to the ridge on the top of the wall; s. the top of said first side wall containing a multiplicity of slots adjacent its exterior surface; t. the bottom of said first side wall containing a multiplicity of tongues adjacent its exterior surface and corresponding to the slots at the top of the wall; u. the top of said second side wall containing a multiplicity of slots adjacent its exterior surface; v. the bottom of said second side wall containing a multiplicity of tongues adjacent its exterior surface and corresponding to the slots at the top of the wall; w. the outwardly facing wall of said first upper removable insert member containing ribs and grooves in alignment with the ribs and grooves in said first end wall; x. the outwardly facing wall of said first lower removable insert member containing ribs and grooves in alignment with the ribs and grooves in said first end wall; y. The outwardly facing wall of said second upper removable insert member containing ribs and grooves in alignment with the ribs and grooves in said second end wall; z. the outwardly facing wall of said second lower removable insert member containing ribs and grooves in alignment with the ribs and grooves in said second end wall; aa. the top of said first upper removable insert member containing ribs extending along the width of the top and along the thickness of the top; bb. the bottom of said first lower removable insert member containing grooves along the width of the bottom and along the thickness of the bottom to correspond with the ribs at the top of the first upper insert member; cc. the top of said second uper removable insert member containing ribs extending along the width of the top and along the thickness of the top; dd. the bottom of said second lower removable insert member containing grooves along the width of the bottom and along the thickness of the bottom to correspond with the ribs at the top of the second upper insert member; ee. the arrangement of ribs and grooves in the first and second side walls, first and second end walls, first and second upper removable insert members, and the first and second lower removable insert members being arranged so that adjacent blocks can be interlocked end to end, end to side, in complete alignment with top to bottom or offset in alignment with a portion of the bottom interlocked with each of two adjacent tops; ff. said hollow rectangular shaped block further comprising a multiplicity of transverse walls disposed between said first and said second side walls to thereby form a multiplicity of chambers within the block; gg. each of said transverse walls containing an upper arcuate recess corresponding to the upper arcuate recess in the first and second end walls; hh. each of said transverse walls containing a lower arcuate recess corresponding to the lower arcuate recess in the first and second end walls; and ii. said first and second end walls and said transverse walls containing aligned grooves in their upper arcuate recess portions.