Pilot device for a suspended knife of a cutting machine for cutting sheet material

In an automatically controlled cutting machine for cutting fabric sheet material spread out on a cutting table in multiple layers, wherein a cutting tool, which includes a cutting knife mounted to a cutting head, is controlled according to a three-dimensional coordinate system by means for moving the cutting tool along the X-and Y-axis and pivoting about the Z-axis for moving the knife tangently along a predetermined cutting path during cutting of the material, said cutting knife being mounted to said cutting head so as to be reciprocally movable along said Z-axis, said cutting tool further including guiding means for guiding the cutting knife and a pressure foot rigidly connected to the cutting head, the improvement comprising that:

• said knife has a first end which is mounted in the cutting head so as to be freely rotatable around the Z-axis and a second end which includes a cutting edge for engaging the sheet material;
• said guiding means is arranged adjacent to the second end of the knife and includes a socket rigidly connected to the cutting head and a support which is freely and rotatably mounted in said socket around a vertical axis, wherein the vertical axis is located adjacent to the cutting edge of said knife and spaced from said knife, and further wherein the vertical axis is parallel and spaced a predetermined distance from the Z-axis of the coordinate system;
• said knife extends through said socket and through a slot in said support, said slot surrounding flanks of the knife and said slot is eccentrically positioned relative to said vertical axis and extends to a trailing edge of the knife;
• and
• said socket further includes a sensor means for detecting at least one of an instantaneous rotation angle and a rotation direction of the support relative to the socket for providing correcting signals for controlling the movement of the knife about the Z-axis to regulate the cutting of the material by the knife along the predetermined cutting path in response to one of the detected rotation angle and rotation direction.