Patent ID: 7814632

Claim:
A method for break separation of pieces that can be re-assembled or their starting materials, whereby the piece or its starting materials is to break separate at a selected break surface, the method comprising: applying to a piece to be subjected to break separation a break force perpendicular to the selected break surface; and before the time at which the piece is subjected to the break force, applying a non-deforming compressive force to the piece perpendicular to said break force to induce a tensile stress, wherein said tensile stress is aligned to the break force and thereby supports the break force, wherein the tensile stress has a maximum that occurs in the plane of the selected break surface perpendicular to the break surface, such that the level of stress produced is still below the elastic limit of the material of the piece such that the piece does not undergo a material deformation as a result of the break separation, wherein the compressive force is applied to the piece that is to subjected to break separation by means of wedges or shear plates that simultaneously act upon the perimeter line of the selected break surface in a pointwise or linear manner with a sharp tip or edge, wherein said wedges or shear plates face one another on opposite sides of the selected break surface, wherein the compressive force continues at least until the piece is first subjected to the break force, and wherein sub-pieces formed from the break separation are configured to be reassembled by being re-fitted together along corresponding edges of said break surface.