Method of forming a cavity structure with a thin bottom base plate

A method for forming a cavity structure according to clam 1, wherein said coupling section is approximately equal to said bottom plate in thickness.

A method for forming a cavity structure according to clam 1, wherein the step of plastically deforming the metal plate is executed by the use of a press and the step of removing said protrusion from the metal plate is executed by cutting.

A method for forming a cavity structure according to clam 1, wherein said oddly bottom surface comprises supporting means for supporting equipment parts to be installed in said cavity.

A method for forming a cavity structure according to clam 3, wherein said press comprises a punch having a shape for defining an outline of said cavity and a die on which the metal plate is supported, said die having a die concave at a position opposite to said punch, said die concave defining an outline of said protrusion and being formed smaller than said punch in such manner that a surface of said die surrounding said die concave is opposing to an edge periphery surface of said punch, and wherein said method comprises the steps of:

• pressing said part of the metal plate by means of said punch so as to form said cavity while forming said protrusion in said die concave;
• and
• stopping said punch at a position where an interval between said surface of said die surrounding said die concave and said edge periphery surface of said punch is equal to a thickness of said coupling section.

A method for forming a cavity structure according to clam 3, further comprising a step of;

• cutting whole surface of said second surface side of the metal plate so as to form said bottom plate thinner.

A method for forming a cavity structure according to clam 3, wherein the step of removing said protrusion from the metal plate is executed in such a manner that said protrusion is cut repeatedly and bit by bit until an cut surface of said protrusion reaches said coupling section.

A method for forming a cavity structure according to clam 7, wherein the step of removing said protrusion form the metal plate is executed by means of a cutting tool which cut alternately into a regular direction and a counter direction.

A method for forming a cavity structure according to clam 1, wherein depth of said subsections of said oddly bottom surface is substantially equal to height of said oddly top surface of said protrusion corresponding to said subsections.

A method for forming a cavity with a thin bottom plate according to clam 10;

• wherein said coupling section is approximately equal to said bottom plate in thickness, and said hollowed section is formed on said first surface side of the metal plate while keeping said second surface side of the metal plate flat.

A method for forming a cavity provided with a thin bottom plate according to clam 10, wherein the step of plastically deforming the metal plate is executed by the use of a press which comprises a punch having a shape for defining an outline of said hollowed section and a die for supporting the metal plate on, said die having a die concave at a position opposite to said punch, said die concave defining an outline of said protrusion and being formed smaller than said punch in such manner that a surface of said die surrounding said die concave is opposing to an edge periphery surface of said punch, and wherein said method comprises the steps of:

• pressing said part of the metal plate by means of said punch so as to form said hollowed section while forming said protrusion in said die concave;
• and
• stopping said punch at a position where an interval between said surface of said die surrounding said die concave and said edge periphery surface of said punch is equal to a thickness of said coupling section at the last step of forming said hollow section as said cavity..

A method for forming a cavity provided with a thin bottom plate according to clam 10, wherein the step of removing said protrusion from the metal plate is executed in such a manner that said protrusion is cut repeatedly and bit by bit until an cut surface of said protrusion reaches said coupling section.

A method for forming a cavity provided with a thin bottom plate according to clam 13, wherein the step of removing said protrusion form the metal plate is executed by means of a cutting tool which cut alternately into a regular direction and a counter direction so that the number of cutting in the regular direction is equal to the number of cutting in the counter direction.

A method for forming a cavity provided with a thin bottom plate according to clam 10, further comprising a step of;

• cutting whole surface of said second surface side of the metal plate so as to form said bottom plate thinner.

A method for forming a cavity provided with a thin bottom plate according to clam 10, wherein said cavity comprises supporting means for supporting equipment parts to be installed therein, said supporting means being defined by said predetermined shape of said bottom plate.

A method for forming a cavity structure according to clam 17, wherein said oddly bottom surface comprises supporting means for supporting equipment parts to be installed in said cavity.

A method for forming a cavity structure according to clam 17, wherein the step of removing said protrusion form the metal plate is executed by means of a cutting tool which cut alternately into a regular direction and a counter direction so that the number of cutting in the regular direction is equal to the number of cutting in the counter direction.