Patent ID: 8028482

Claim:
A device ( 1 ) for forming contraction joints in concrete works, comprising: a plurality of stiff linear members ( 7 , 9 , 11 ) connected by supports ( 5 , 5 ′) between them such that the stiff linear members ( 7 , 9 , 11 ) form a three-dimensional triangular structure having two faces and a base; and a plurality of trays ( 3 , 3 ′; 12 , 12 ′) of a concrete divider material, alternately arranged on the two faces of the triangular structure on either side of one of the stiff linear members ( 11 ), having gaps ( 16 ) between the trays ( 3 , 3 ′; 12 , 12 ′), wherein at least one tray is formed by two half-trays ( 14 , 15 ), each half-tray ( 14 , 15 ) having a broken surface formed with an upper portion ( 17 ) and a lower portion ( 19 ) that are parallel to each other and tilted at an acute angle I with respect to a base of the triangular structure, the upper portion ( 17 ) and the lower portion ( 19 ) being connected by a central portion ( 21 ) that is at an angle C with respect to the base of the triangular structure.