Method and apparatus for forming a contoured surface

A method of forming a contoured surface with a compound curvature on a block comprising the steps of:

• mounting the block to be contoured on a cradle having a translational direction and a rotational axis substantially parallel with the translational direction;
• presenting a substantially linear cutting member substantially perpendicular to the translational direction and non-parallel with the rotational axis;
• simultaneously effecting selective translation and rotation of the cradle relative to the cutting member;
• and,
• cutting the block with the cutting member in response to the simultaneous relative translation and rotation to form a contoured surface on the block.

Apparatus for forming a saddle-shaped contoured surface on a block comprising:

• cradle means adapted to support the block;
• said cradle means having axle stubs to define a rotational axis;
• carriage means for supporting said cradle means for rotation about said rotational axis;
• said carriage means being translatable along a translational direction;
• linear cutting means disposed substantially perpendicular to said rotational axis;
• means for providing relative linear motion between said carriage and said cutting means;
• and,
• means for effecting rotation of said cradle relative to said cutting means in response to translation of said cradle.

Apparatus for forming a contoured surface on a block comprising:

• cradle means having a first rotational axis;
• means for supporting the block relative to said rotational axis;
• a guide member rotatable about a second rotational axis;
• carriage means for supporting said cradle means;
• a base for supporting said carriage means;
• means for moving said carriage means along a translational direction;
• means for supporting said guide member on said base at a predetermined orientation with respect to said translational direction;
• means for effecting rotation of said cradle through a predetermined range;
• cutting means disposed in a plane substantially perpendicular to said first rotational axis.

Apparatus for forming a contoured surface on a block, said apparatus comprising:

• cradle means to support a block of material on which the contoured surface is to be formed;
• means to rotate said cradle means about a rotational axis;
• means to move said cradle along a translational direction;
• means to control rotation of said cradle in response to translation of said cradle according to the function tan .THETA.=kx, wherein .THETA. designates the incremental angular rotation of said cradle, "k" represents a constant and "x" is the incremental distance the cradle has been translated from a reference position;
• and,
• linear cutting means disposed parallel to said first reference plane and intersecting said rotational axis.

Apparatus for forming a contoured surface on a block, said apparatus comprising:

• cradle means to support a block of material on which the contoured surface is to be formed;
• linear cutting means;
• means to effect relative rotation between said cradle means and said linear cutting means about a rotational axis;
• means to effect relative translation between said cradle and said cutting member along a translational direction;
• means to control said relative rotation in response to said translation according to the function tan .THETA.=kx, wherein .THETA. designates the incremental, relative angular rotation, "k" represents a constant which is determined by the nature of the means to control said relative rotation between said cradle means and said cutting means and "x" is the incremental distance achieved by said relative translation.

A method for forming a contoured surface in the nature of a hyperbolic paraboloid to serve as a back cushion for humans, the cushion having a sagittally oriented lumbar supporting portion and lateral wings, the cushion being cut from a square block of material and the method comprising the following steps:

• determining the side dimensions "A" of the square block of material;
• selecting the desired minimal thickness "T.sub.L " of the desired cushion measured along a sagittal plane of what will be the lumbar supporting portion;
• selecting the desired maximum thickness "T.sub.W " of the desired cushion measured at the wings;
• mounting the block to be contoured on a cradle having a translational direction and a rotational axis;
• presenting a substantially linear cutting member substantially perpendicular to the translational direction;
• interfacing the cradle with a rotational rate selector in order to control relative rotation of the cradle in response to relative translation thereof;
• disposing the centerline of the rotational rate selector at an angle .PHI. relative to the translational direction;
• determining the distance "d" from the rotational axis of the cradle to the centerline of the rotational rate selector;
• adjusting the angular disposition of the rate selector by the formula ##EQU3## simultaneously effecting selective translation and rotation between the cradle and cutting member;
• and,
• cutting the block with the cutting member in response to the simultaneous relative translation and rotation to form the desired contoured surface on the block.